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APPENDIX G
Geochemistry Assessment
REPORT
Preliminary Geochemistry ARD/ML Assessment for the Proposed Metsimaholo Underground Mine Seriti Coal (Pty) Ltd
Submitted to:
Seriti Coal (Pty) Ltd 3 On Glenhove c/o Glenhove and Tottenham Ave Melrose Estate Johannesburg
Submitted by:
Golder Associates Africa (Pty) Ltd. Building 1, Maxwell Office Park, Magwa Crescent West, Waterfall City, Midrand, 1685, South Africa
P.O. Box 6001, Halfway House, 1685
+27 11 254 4800
18101804-324369-12
February 2019
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Distribution List 1 x electronic copy Seriti Coal (Pty) Limited
1 x electronic copy e-projects library [email protected]
1 x electronic copy Golder project folder
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Record of Issue
Company Client Contact Version Date Issued Method of Delivery
Seriti Coal (Pty) Ltd Kim McCann Draft 13 March 2019 Email
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GLOSSARY OF TERMS
Term Description
Acid-base accounting
(ABA)
An analytical technique applied to mine wastes and geologic materials that
determines the potential acidity from sulphur analysis versus the neutralisation potential. It is used to predict the potential of that material to be acid producing or acid neutralising.
Acid generating Coal and mine wastes that contain sulphur or sulphides, which produce acid when oxidised. Acid can also be present as acid-bearing sulphates or
generated by their weathering, produced originally from oxidation of sulphides.
Acid potential (AP) The ability of a rock or geologic material to produce acid leachates; may also be
referred to as acid generation potential or AGP.
Acid rock drainage
(ARD)
Low pH drainage that is formed by the natural oxidation of sulphide minerals,
together with reactions of base minerals in the rock, which are exposed to air and water. The drainage produced from the oxidation process contains sulphate and it may be neutral to acidic, with or without dissolved heavy metals.
Acidity The titratable acid as measured in accordance with standard methods. It is
normally reported as milligrams per litre as calcium carbonate (CaCO3).
Alkalinity The titratable alkalinity, using a standard acid titrant, as performed in accordance with standard methods. It is normally reported as milligrams per litre
as calcium carbonate (CaCO3).
Anion An ion with a negative charge.
Amphoteric Amphoteric species is a molecule or ion that has both acid and base properties. Amphoteric oxides affect solubility and will dissolve in either a strong acid or a
strong base. Hydroxides generally form complex ions with four hydroxide ligands attached to the metal: Al(OH3) (s) + OH-(aq) Al(OH)4-(aq) There are a number of metals exhibiting amphoterism, including Zn, Pb, Sn, Cr,
Be, As, Sb, B, Si, Ge, V, Zn and Te.
Backfill Geologic materials returned to an open pit or placed back into an underground
mine, after desirable minerals have been removed, to bring a surface mine back to original contour, partially refill an open pit, or to improve stability of underground workings.
Cation An ion with a positive charge.
Composite sample A sample made by the combination of several distinct subsamples.
Conceptual site model A representation of a site and its environment that represents what is known or
suspected about contaminant sources as well as pathways to potential environmental receptors.
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Term Description
Contaminant Any physical, chemical, biological, or radiological substance or matter that has
an adverse effect on human and ecological receptors as well as environmental media (e.g. air, water, soil, sediment).
Dissolved solids The weight of both organic and inorganic matter, in solution in a stated volume
of water. The amount of dissolved solids is usually determined by filtering water through a glass or 0.45 μm pore-diameter filter, weighing the filtrate residue
remaining after the evaporation of the water, and drying the salts to constant weight at 180°C.
Electrolytic conductivity The ability of a solution to conduct electricity. It is indicative of the concentration of ionised constituents in a water sample or soil matrix. Also referred to as
electro conductivity.
Kinetic Testing A laboratory geochemical procedure to accelerate natural oxidation (weathering) reactions so that the potential rate of the rock to generate acid
drainage can be evaluated.
Leaching The removal by dissolution, desorption, or other chemical reaction of material
from a solid matrix by passing liquids through the material.
Metal Leaching (ML) The release of metals from mineral phases by leaching.
Lithology The character of a rock described in terms of its structure, colour, mineral composition, grain size, and arrangement of its visible features that in the
aggregate impart individuality to the rock.
Neutral mine drainage
(NMD)
A neutral to alkaline pH, metal-laden, sulphate-rich drainage that occurs during
land disturbance where sulphur or metal sulphides are exposed to atmospheric conditions. It forms under natural conditions from the oxidation of sulphide minerals and where the alkalinity equals or exceeds the acidity.
Neutralisation potential
(NP)
The amount of alkaline or basic material in rock or overburden materials that is
estimated by acid reaction followed by titration to determine the capability of
neutralizing acid from exchangeable acidity or pyrite (FeS2) oxidation. Neutralisation potential is comprised of more reactive minerals, such as carbonate, that provide short-term buffering and less reactive minerals such as
alumino-silicates, that provide longer-term buffering.
Net Neutralisation
Potential (NNP)
The difference of Neutralisation Potential (NP) and Acid Potential (AP) that
determines based on criteria weather a material is acid generating or not. The lower the NNP, the higher the potential for acid generation.
Neutralisation potential ratio (NPR)
The NPR is defined as NP/AP. The lower NPR, the higher the potential for acid generation.
Neutralisation reaction A chemical reaction in which an acid and a base or alkali (soluble base) react to
produce salt and water, which do not exhibit any of the acid or base properties.
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Term Description
Ore deposit A mineral deposit that has been tested and found to be of sufficient size, grade,
and accessibility to be extracted for a profit at a specific time, based on economic assumptions.
Overburden Material of any nature consolidated or unconsolidated, that overlies a deposit of
useful and minable materials or ores, especially those deposits that are mined from the surface by open cuts or pits.
Oxidation A chemical process involving a reaction(s) that produces an increase in the oxidation state of elements.
Pathway The physical course a chemical or pollutant takes from its source to a receptor.
pH A measure of the acidity (pH less than 7) or alkalinity (pH greater than 7) of a
solution; a pH of 7 is considered neutral. It is a measure of the hydrogen ion concentration (negative log of the hydrogen ion activity for glass electrodes) of a
soil suspension or solution.
Receptor An ecological entity or water use exposed to a stressor.
Redox Chemical reactions in which atoms have their oxidation state changed, through
the transfer of electrons. Oxidation is loss of electrons, reduction is gain.
Representative sample A portion of material or water that is as nearly identical in content and consistency as possible to that in the larger body of material or water being
sampled.
Saline drainage (SD) Drainage that contains high levels of sulphate at neutral pH without significant
metal concentrations.
Stratigraphy The layering or bedding of varying rock types reflecting changing environments
of formation and deposition. Also, a branch of geology that concerns itself with the study of rock layers and layering (stratification).
Sulphide Sulphur The sulphur component of a solid material that is comprised of sulphide. With
respect to acid base accounting, sulphide sulphur is the component that is most commonly used to calculate the acid potential.
Sulphate Sulphur The sulphur component of a solid material that is comprised of sulphate.
Static Test A procedure such as acid base accounting for characterising the physical and or chemical properties of a sample at a point in time, but not the weathering rates
of the materials.
Total Sulphur The sum of all sulphur species of a solid material.
Vadose zone The portion of earth between the land surface and the water table or zone of saturation. Also named the unsaturated zone.
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Term Description
Waste rock Barren or mineralized rock that has been mined but is of insufficient value to
warrant treatment and is removed ahead of the metallurgical processes and disposed of on site. The term is usually used for wastes that are larger than sand-sized material and can be up to large boulders in size.
Weathering Process whereby earthy or rocky materials are changed in colour, texture, composition, or form (with little or no transportation) by exposure to atmospheric
agents.
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ACRONYMS
Acronym Term in full
ABA Acid-based accounting
AP Acid potential
ARD Acid Rock Drainage
GARD Global Acid Rock Drainage guide
ICP Inductively Coupled Plasma
ICP-MS Inductively Coupled Plasma - Mass Spectrometry
ICP-OES Inductively Coupled Plasma - Optical Emission Spectrometry
ML Metal leaching
NMD Neutral Mine Drainage
MLMH Middle Lower Mining Horizon (Middle seam)
NNP Net neutralisation potential
NPAG Not Potentially acid generating
NP Neutralisation potential
PAG Potentially acid generating
PCoC Potential constituents of concern
ppm Parts per million
QA/QC Quality Assurance / Quality Control
ROM Run of mine
SD Saline Drainage
SNPR Sulphide Neutralisation Potential Ratio
SPLP Synthetic Precipitation Leaching Procedure (US EPA 1312) – a short term LP
SPR Source-pathway-receptor approach
STLP (or SLP) Short-term Leaching Procedure
TCLP Toxicity Characteristic Leaching Procedure (US EPA 1311) – – a short term LP
TDS Total Dissolved Solids
TMH Top Mining Horizon (Top Seam)
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Acronym Term in full
TNPR Total Sulphur Neutralisation Potential Ratio
UGM Underground Mine
WR Waste Rock
XRF X-Ray Fluorescence
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Table of Contents
1.0 INTRODUCTION ...................................................................................................................................... 1
2.0 OBJECTIVES ........................................................................................................................................... 1
3.0 METHODOLOGY AND APPROACH ....................................................................................................... 1
3.1 Legal Framework ............................................................................................................................ 1
4.0 PROJECT DESCRIPTION ....................................................................................................................... 2
4.2 Geology .......................................................................................................................................... 5
4.3 Hydrogeology ................................................................................................................................. 7
5.0 MATERIAL CHARACTERISATION ......................................................................................................... 9
5.1 Sample Availability .......................................................................................................................... 9
5.2 Chemical Properties ..................................................................................................................... 10
5.2.1 Acid-generating and neutralising potential ................................................................................ 10
5.2.1.1 ARD POTENTIAL ..................................................................................................................... 14
5.2.2 Net Acid Generation (NAG) ...................................................................................................... 15
5.2.3 Metal Leaching ......................................................................................................................... 16
5.3 Additional ARD test work .............................................................................................................. 18
5.3.1 Roof and Floor Metal Leaching ................................................................................................. 22
5.4 Kinetic Test work .......................................................................................................................... 23
5.4.1 Particle Size Distribution ........................................................................................................... 24
5.4.2 Mineralogical Composition ........................................................................................................ 24
5.4.3 Acid Base Accounting ............................................................................................................... 25
5.4.4 Kinetic Test Results ............................................................................................................... 27
5.5 Propensity for spontaneous combustion ....................................................................................... 29
5.6 Toxicity ......................................................................................................................................... 29
5.7 Physical properties ....................................................................................................................... 29
6.0 RISK ASSESSMENT ............................................................................................................................. 29
6.1 Preliminary risk assessment for WRD ........................................................................................... 31
6.2 Preliminary risk assessment for Underground Mine ........................................................................... 32
7.0 CONCLUSIONS AND RECOMMENDATIONS ...................................................................................... 33
8.0 REFERENCES ....................................................................................................................................... 35
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TABLES
Table 1: Geochemical samples collected for Metsimaholo as part of the previous New Vaal Lifex EIA (Golder, 2013) ................................................................................................................................................................. 9
Table 2: ARD assessment guidelines as provided by MEND (2009) ................................................................ 14
Table 3: Summary of deionised water leach (S:L of 1:4) results (orange highlight indicate exceedance of Class 0&1) ................................................................................................................................................................. 16
Table 4: Summary of deionised water leach (S:L 1:1) results for Metsimaholo roof & floor samples ............... 22
Table 5: Humidity cell setup composite samples for Vaalbank, Metsimaholo and New Vaal mine blocks ........ 23
Table 6: Summary of ABA results for HC composite samples ......................................................................... 25
Table 7: Summary of characterisation results for Metsimaholo coal and inter-burden/overburden samples .... 31
FIGURES
Figure 1: Flowchart for mine residue characterisation in terms of GN R. 632 of 2015 (as amended) ................. 2
Figure 2: Proposed Metsimaholo Colliery location indicating geochemical boreholes sampled during Golder Lifex Study (2013) .............................................................................................................................................. 3
Figure 3: Preliminary infrastructure layout (Seriti, 2018) .................................................................................... 4
Figure 4: Geological Map for the Proposed Metsimaholo Colliery ...................................................................... 6
Figure 5: Typical Vaalbank and Metsimaholo stratigraphic column (Golder, 2013) ............................................ 7
Figure 6: Geochemical sample locations for Block 1, Vaalbank and Metsimaholo (Coalbrook) (Golder, 2013) 11
Figure 7: Paste pH vs sulphide S% for Metsimaholo (Golder, 2013) ................................................................ 12
Figure 8: Carbonate NP versus bulk NP for Metsimaholo overburden/interburden and coals samples (Golder,2013) ................................................................................................................................................... 13
Figure 9: NP versus SAP for Metsimaholo overburden/interburden and coal samples (Golder, 2013)............. 14
Figure 10: Paste pH versus SNPR for Metsimaholo overburden/interburden and coal samples. ..................... 15
Figure 11: NAG pH versus Paste pH for Metsimaholo overburden/interburden and coal samples (Golder, 2013) ........................................................................................................................................................................ 16
Figure 12: Box whisper plots (paste pH, Sulphide S, NP and NPR) for Metsimaholo roof samples (n=12) ...... 18
Figure 13: Box whisper plots for pH and NP for Metsimaholo floor samples (n=10) ......................................... 18
Figure 14: Plot of Paste pH vs Sulphide S for Metsimaholo roof material ........................................................ 19
Figure 15: Plot of NP vs SAP for Metsimaholo roof material ............................................................................ 19
Figure 16: NAG pH for Metsimaholo roof samples ........................................................................................... 20
Figure 17: Plot of Paste pH vs Sulphide S for Metsimaholo floor material ....................................................... 21
Figure 18: Plot of NP vs SAP for Metsimaholo floor material ........................................................................... 21
Figure 19: Particle size distribution for New Vaal Colliery Humidity cell samples, WRTM4 and WRTM5 ......... 24
Figure 20: Mineralogical composition of HC samples ...................................................................................... 25
Figure 21: New Vaal Lifex HC samples (Golder, 2013) .................................................................................... 26
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Figure 22: Kinetic results for pH, EC and sulphate for Metsimaholo coal composites ...................................... 27
Figure 23: Kinetic results for pH, EC and sulphate Vaalbank overburden/interburden composites .................. 28
Figure 24: Flowchart for mining residue facility environmental risk assessment in terms of GN R. 632 of 2015 ........................................................................................................................................................................ 30
APPENDICES
APPENDIX A Mine design
APPENDIX B Borehole logs and geochemical samples
APPENDIX C Static results summary
APPENDIX D Kinetic results summary
APPENDIX E Metsimaholo roof and floor NAG leach results
APPENDIX F Document Limitations
APPENDIX G Specialist Declaration and CV
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1.0 INTRODUCTION Golder Associates Africa (Pty) Ltd (Golder) was commissioned to conduct a geochemistry risk assessment for
the proposed Metsimaholo Colliery as part of the application for the Metsimaholo (previously Coalbrook) mining rights retention. According to the previous geochemistry specialist study, a risk of Acid Rock Drainage (ARD) and Metal Leaching (ML) is associated with the geological materials that will be disturbed by the planned
underground mining operations. These risks are also associated with the various coal seams (top and middle)
that will be mined, as well as carbonaceous overburden and interburden (mudstone, grit and sandstones) in
contact with the coal seams.
The aim of the previous geochemical study (Golder, 2013) was to characterise the mining-disturbed material with respect to ARD and ML to indicate those materials likely to give rise to environmental risks during the Life
of Mine (LoM) and predict mine water quality.
This report presents the Metsimaholo geochemical characterisation results as a basis for the ARD/ML risk
potential from the proposed Underground Mine (UGM). The available data would be used to provide first order source-term ranges to enhance longer term groundwater quality prediction linked to the simplified flow modelling
and mine water balance proposed.
2.0 OBJECTIVES The objectives of the geochemical assessment are:
To assess ARD and ML potential of the various geological strata that will be disturbed by the planned
mining operations based on previous available geochemical characterisation results; and
To identify potential information and knowledge gaps for studies to be conducted during the subsequent permitting and licencing processes.
3.0 METHODOLOGY AND APPROACH
The approach adopted in this geochemical assessment is based on best practice methodology to characterise
mine drainage consistent with the national and international best practice guidance documents listed below:
Prediction Manual for Drainage Chemistry from Sulphidic Geologic Materials (MEND 2009).
Global Acid Rock Drainage (GARD) Guide (INAP, 2013).
This report is based on existing geochemical results obtained for the Metsimaholo (previously known as Coalbrook) licence area which was part of the previous New Vaal Lifex EIA (Golder, 2013).
3.1 Legal Framework The environmental aspects of the design and management of mine residues (i.e. dumps or stockpiles of waste rock, overburden – carbonaceous and non-carbonaceous material, ROM) are governed by the National
Environmental Management: Waste Act (NEM:WA). The Regulations Regarding the Planning and Management of Residue Stockpiles and Residue Deposits from a Prospecting, Mining, Exploration or Production Operation
(GN R. 632 of 2015) provide for the characterisation of mine residues (all forms of mine waste and stockpiles)
as input to a risk assessment (Figure 1). In addition to minerology and chemical properties, an understanding
of the toxicity and physical properties is required to inform a Source-Pathway-Receptor risk assessment.
According to GN R. 632 of 2015, a pollution control barrier system is to be driven by the Waste Classification and Management Regulations (GN R. 634-636 of 2013), based upon the leachable and total concentrations of
specified constituents of concern. The subsequent amendment to GN R. 632 of 2015 (GN 990, 21 September
2018), removed the reference to the Waste Classification and Management Regulations such that that the
pollution control barrier system be driven by a risk assessment based on the material characteristics.
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The geochemical characterisation of the coal and residue materials produced at the proposed Metsimaholo
Colliery in terms of Regulation 4 of GN R. 632 of 2015 is provided in Section 5.0.
Figure 1: Flowchart for mine residue characterisation in terms of GN R. 632 of 2015 (as amended)
4.0 PROJECT DESCRIPTION The project is situated in the Metsimaholo Local Municipality, in the magisterial district of Sasolburg, in the
northern part of the Free State Province, South Africa. The nearest towns are Refengkgotso (which straddles the north-eastern corner of the project), and Deneysville (which lies a further 3km to the east). The total project area is contained within longitudes Y -86 418 and Y -110 436, and latitudes Х +2 970 212 and Х +2 989 058 in
the Cape Datum (Lo27) survey system. The GPS centroid locality point for the project area is 26°54’43.74” S
and 27°58’43.39” E.
The project area is gently undulating at 1 525 metres above mean sea level (AMSL). The perennial Taaibosspruit River meanders from south to north, through the western side of the project area. The Vaal Dam,
in part, forms the eastern edge of the mining right application area (Figure 2). The Taaibosspruit runs through
the western /central portion of this mining rights area.
The climate is typical of the northern Free State with warm to hot and wet summers and cool to cold, dry winters. The average annual precipitation for this region varies between 580 and 705 mm (Environ-info, 2012). The
mean annual average rainfall for Viljoensdrift is 621 mm (climatic data for Jan 1920 to July 2011 Golder, 2013).
Proposed TDS concentration (95th percentile) Resource Water Quality Objectives (RWQOs) for the Vaal River (Upper Vaal) system; downstream Lethabo weir to Vaal Barrage; and tributaries are as follows: Vaal River 600mg/l, Taaibosspruit 390mg/ℓ; Rietspruit 550mg/ℓ and Kromelmboog 195mg/ℓ (DWAF, 2009). A Reserve WQ
specification of 180 mg/l TDS has been set at the outflow of Vaal Dam (currently being gazetted).
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Figure 2: Proposed Metsimaholo Colliery location indicating geochemical boreholes sampled during Golder Lifex Study (2013)
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The project is based on an independent mine producing thermal coal from one operational decline shaft. The
ROM production profile is approximately 3Mtpa, depleting in 2054. The project is planned to commence in 2023
with the pre-construction and construction phase and initial production in 2025.
Access to the coal seams is planned through a box-cut development (~4.5ha and 1.3 million BCM overburden generated), with a twin decline shaft system to intersect the top seam (Top Mining Horizon - TMH) floor and the
middle seam (Middle Lower Mining Horizon - MLMH) floor from which the shaft bottom development and main
primary development would be initiated (APPENDIX A). MLMH will be accessed from underground via a developed decline. Main access development is planned from the decline shaft floor as a 7-road development providing access to people, material and services.
Bord and pillar mining using continuous miners (CM’s) was selected as the primary extraction method. Once
access is gained into the coal seam, workings are developed by mining a series of roadways (or "headings"). Perpendicular roads, called splits, are developed at predetermined intervals to the parallel roads. These roads
interlink, creating pillars. The road widths were designed at 7.2m wide with an average mining height of 3m. The main development and production sections consist of either seven or nine roadways which constitutes a
mining panel.
Water balance determined that the operations will require total water usage of 2084 m³/day. A total of 50% import water usage for underground will supplement the raw water for reuse in underground operations from
the nearby infrastructure. The following infrastructure information has been provided by Seriti (Figure 3):
Total mining block footprint area is 245ha;
Total infrastructure footprint area required is 60ha with the access footprint ~ 30ha and the infrastructure
area ~ 20ha;
Figure 3: Preliminary infrastructure layout (Seriti, 2018)
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Overburden/Waste rock dump total footprint is estimated at 10ha, of which the overburden dump is 6.5ha
(380m by 170m) and the topsoil dump is 3.5ha (500m by 70m). The total overburden to be excavated from
the box-cut ~ 1.3 million BCM (surface area of 4.5ha);
Coal mining and handling. The CM uses the cutting head which is a rotating drum with cutting picks attached to cut the coal face. A loading mechanism picks up cut coal and deliver it into the central part of the machine. A conveying system, (chain conveyor) is used to run the coal in a steel trough from front to
rear of the miner. A rear jib section capable of vertical and horizontal movement is used to enable the coal to be delivered into a shuttle car. The loaded shuttle car is used to haul the coal to the section feeder
breaker which crush and feed the coal on the conveyor belt system. A conveyor belt system is used to
transport the coal from the mining section to surface silo’s for distribution to the market; and
400Ml balancing dam and 18.5Ml Pollution Control Dam (PCD) at the mine infrastructure to store UGM
mine water and surface runoff water will be captured in open channels/drains that gravitate to the PCD.
4.2 Geology The study area is located in the Vereeniging Sasolburg Coalfield in a large north–south trending palaeovalley. The geology of the area is made up of various lithological successions of mostly the Karoo Supergroup. The
1:250 000 geological map describes the lithologies as recent alluvium with underlying mudstone, sandstones
and shale of the Volksrust Formation and Vryheid Formation of the Permian age Ecca Group.
The whole of the Vaalbank and New Cornelia area and some of the Metsimaholo area is covered by a layer of
alluvium (Figure 4). The alluvium consists of fine to very fine sand, lenses of clay and boulder beds. The main difference in geological succession between Vaalbank and Metsimaholo is the presence of the thick extensive
dolerite sill in the Metsimaholo area (Golder, 2010).
The base of the Karoo sequence in the study area consists of rocks of the Dwyka Group. The Group consist of
a complex mixture of sandstones, feldspathic sandstones, mudstones, conglomerates and both in-situ and reworked tillites. Due to being deposited in a palaeovalley, the Dwyka Group sequence varies from being over 40 m thick in the central parts of the palaeovalley to being absent on the flanks of the palaeovalley. There is
also considerable local variation in the thickness (and nature) of the Dwyka Group sediments due to irregularities in the floor of the palaeovalley. The general dip of the whole sequence in the area is to the south-south-east
following the basin morphology.
Overlying the Dwyka Group is the Ecca Group (~50-100m thick). This Group consist of the sequence between the Dwyka and Soft Overburden (Figure 5) and is made up of the Vryheid and Volksrust Formations. The Vryheid
Formation, consisting of coal seams, mudstones, siltstones and sandstones, rests directly on the Dwyka Group. The Volksrust Formation, consisting of mudstones and siltstones, which very commonly decompose rapidly on exposure, overlies the Vryheid with a gradational contact. The sediments are commonly found in coarsening
upward sedimentary cycles. The non-coal sedimentary rocks constitute the Hard Overburden, Inter-burden and
Parting of coal seams, namely Bottom Seam, Middle Seam and Top Seam (Figure 5).
The Vryheid Formation underlies the Volksrust Formation as the main coal bearing formation. The coal zone in this coalfield is approximately 40 m thick and consists of three coal units. The lower coal unit is underlain by shale and tillite of Dwyka Group sediments which vary in thickness (<20 m). The tillite is normally described as
impermeable (aquitard) and could therefore act as a horizontal barrier to groundwater movement. In the Vaalbank and New Cornelia areas the lower coal layer was found at between 50 and 180 mbgl, and for the
Metsimaholo area it was found at 100 to 300 mbgl (Golder, 2010)
Younger intrusions in the form of dolerite dykes and sills have displaced the sedimentary strata. The geophysical
survey results were successful to locate several of these structures, especially dolerite dyke intrusions. The
main sill in the Metsimaholo area intruded approximately 25 m above the Upper coal unit. A major E -W trending
fault zone provides the boundary between the Vaalbank and Metsimaholo areas.
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Figure 4: Geological Map for the Proposed Metsimaholo Colliery
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Figure 5: Typical Vaalbank and Metsimaholo stratigraphic column (Golder, 2013)
The Bottom Seam (BS) is usually, but not always, present as it directly overlies the Dwyka Group. The average thickness of the seam is 3 m. Directly above the bottom seam is the Parting Seam (PS). This is a non-coal unit
that typically consists of coarse grained sandstone and grit. Carbonaceous, silty to gritty mudstone can also occur in the PS. Overlying the Parting Seam is the Middle seam, which is subdivided into the MUMH (Middle
(seam) Upper Mining Horizon), the MP (Middle Parting) and the MLMH (Middle (seam) Lower Mining Horizon).
The Lower mining horizon (MLMH) is targeted at Metsimaholo. The seam is typically 10 m thick and thins sharply to almost non-existence in the extreme north-eastern corner of this particular area against the eastern flank of
the major palaeovalley. A pronounced thinning of the seam is also evident along the whole of the western side of the Vaalbank mining block, again due to the presence of a flank of the palaeovalley. Locally, particularly on the south western fringe of the Vaalbank Block, the Middle Seam can rest almost directly on the Pre-Karoo floor
(AATC, 2011). APPENDIX B provides the logs for 8 exploration cores in the Metsimaholo Block.
Overlying the middle seam is the inter-burden, which is an upward coarsening sequence, from carbonaceous
mudstone through shale and siltstone to fine grained micaceous sandstone forming the floor of the Top Seam.
A study of exploration borehole logs revealed that the shale, siltstone and sandstone are locally carbonaceous.
The Top Seam is subdivided into the TRF (Top (seam) Roof) and the TMH (Top (seam) Mining Horizon). The seam is typically 5 m thick but thins sharply to being almost non-existent against the eastern flank of the palaeovalley in the north-eastern corner of the Vaalbank reserve. The Top Seam sub crops against the Late
Tertiary-Quaternary alluvial sand deposits on the western flanks
4.3 Hydrogeology The baseline study (Golder, 2010) identified two aquifer systems, a shallow system and a deep system. The
shallow system consists of clay and weathered mudstone, shale, and sandstone. The majority of the water strikes were associated with fracturing of the sandstone. The water strikes recorded below the top coal seam in
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Vaalbank area and below the dolerite sill in Metsimaholo, is considered to represent the deep aquifer system.
The deep aquifer comprises of sandstone, fractured shale and siltstone lenses between coal seams Hydraulic conductivity values of 4 x 10-4 m/d to 0.9 m/d were calculated for the deep aquifer system and 2.4 x 10-5 m/d to 3 m/d were calculated for the shallow system. The depths of the shallow boreholes in the Metsimaholo area
range from 18 mbgl to 30mbgl, whereas deep boreholes are between 100mbgl and 292mbgl. In the Vaalbank and New Cornelia area shallow borehole depths range between 10mbgl and 74mbgl, whereas deep borehole
depths range between 48mbgl and 179mbgl.
Metsimaholo water strikes in the deep boreholes were encountered at depths ranging from 9mbgl to 236mbgl (yields ranging from 0.1l/s to over 12l/s). The shallow water strikes coincided with weathering and associating
shallow fracturing. The deep aquifer show a water strike frequency spread and blow yield frequency spread
throughout the depth range and blow yield range, confirming the anisotropic character of the aquifer.
New Vaal Colliery monitors all boreholes around the mine located in the underground workings, into the spoil material and selected boreholes into the dolomites. The groundwater was found to be good quality (reducing conditions at depth with alkaline pH), and classified as Na-bicarbonate type waters, indicative of mostly recently
recharged water. Exception to these two main groupings are boreholes associated with the old workings, where
elevated sulphate values were measured, and deeper boreholes in the south of Metsimaholo which have a more
NaCl character. Salinity generally increases with depth and towards the southern portion of the study area.
Brief review monitoring data for Betty Shaft borehole (located into the drive of an old mine to the North of New Vaal across the Vaal River) for the period 2000-2005 (n=53) indicates average pH, TDS and SO4 concentrations
as pH = 7.3, TDS = 920 mg/l and SO4 = 327 mg/l respectively.
Structural geology
The main difference in geological succession between Vaalbank and Metsimaholo is the presence of the thick extensive dolerite sill (~50 m thick). Younger intrusions in the form of dolerite dykes and sills have displaced the
sedimentary strata. Displacements of up to 85 meter, by the sills, are a common occurrence in the coalfield. The main sill in the Metsimaholo area intruded approximately 25 meter above the Upper coal unit. Minor faults
with maximum displacements of 5 meter are also reported in the region.
Dolerite sills and dykes were intersected in the Metsimaholo area with the main sill varying in thickness from
40m to >100m. Numerous east - west trending dykes also traverse the area.
Hydrogeological Model
The hydrogeological model developed by Golder (2013) for the New Vaal Lifex and Metsimaholo licence area indicates geology underlying the site constitutes two sedimentary aquifers namely a shallow and deep aquifer.
In the Metsimaholo area the aquifers are separated by a dolerite sill, which changes the nature of the deep
aquifer to a confined system in this area. The shallow system is also semi-confined to confined depending on the characteristics of the shallow sediments and alluvium overlying thicker fractured sandstone sequences. The bottom of the deep aquifer is represented by a Dwyka age tillite which is assumed to act as an aquitard, due to
its low permeability.
Numerical groundwater modelling completed by Golder for Coalbrook (Golder, 2013) consisted of four layers to
account for the two aquifers, dolerite sill and tillite. The existing mine workings was added as high permeability zones and in the case of Metsimaholo, a system which is acting as a hydraulic low for the deep aquifer system
(Golder baseline, 2010).
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5.0 MATERIAL CHARACTERISATION The materials samples and laboratory results from the Golder (2013) New Vaal Lifex EIA study is presented in
the sections that follow.
5.1 Sample Availability Eight (8) exploration core holes selected as part of the Golder New Vaal Lifex study (2013) for the purposes of
geochemical sampling are indicated in Figure 2. Borehole NCLB008 is located close to the proposed shaft,
whilst the NCLB068 and the remaining boreholes are located in the centre and on the western boundary of the Metsimaholo licence area. Based on the mine plan (APPENDIX A) only NCLB008 and NCLB068 fall in the
proposed UGM area. However, assuming geological continuity, all boreholes and samples are deemed
representative the Metsimaholo licence area that is relevant for the proposed Metsimaholo Colliery (Figure 2).
Table 1 summarises the geochemical samples collected and analysed in 2012 by Golder (2013). APPENDIX B
provides the boreholes logs and detailed sample list. Available geochemical characterisation results from the 88 (partings/interburden, coal and overburden (carbonaceous and non-carbonaceous) samples are
summarised in the subsequent sections. Figure 6 provides Vaalbank, Block 1 and Metsimaholo sample
locations.
Table 1: Geochemical samples collected for Metsimaholo as part of the previous New Vaal Lifex EIA (Golder, 2013)
Mining Block
Borehole Sample Name Dominant Lithology1 Lithology Code
Metsimaholo
Overburden Composite Samples (n=8)
NCLB037 NCLB037/01-09 Mudstone-Siltstone MD-ST
NCLB119 NCLB119/01-13 Siltstone-Siltstone/Sandstone ST-SL
NCLB047 NCLB047/01-10 Siltstone/Sandstone-Shale/Sandstone-Dolerite SL-SX-DO
NCLB020 NCLB020/01-10 Mudstone-Carbonaceous Mudstone-Siltstone/Sandstone
MD-MC-SL
NCLB008 NCLB008/01-08 Siltstone/Sandstone-Dolerite SL-DO
NCLB148 NCLB148/01-08 Dolerite-Sandstone DO-SD
NCLB068 NCLB068/01-12 Mudstone-Dolerite MD-DO
NCLB151 NCLB151/01-08 Dolerite-Siltstone/Sandstone DO-SL
Overburden Individual Samples (n=78
NCLB037 See APPENDIX B
Carbonaceous Shale CS
NCLB119 Dolerite DO
NCLB047 Dolerite-Sandstone DO-SD
NCLB020 Grit-Mudstone GR-MD
NCLB008 Gritstone GS
NCLB148 Carbonaceous Mudstone MC
NCLB068 Mudstone-Sandstone MD-SD
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Mining Block
Borehole Sample Name Dominant Lithology1 Lithology Code
NCLB151 Sandstone SD
NCLB151 Sandstone-Sandstone/Shale SD-SX
Shale-Siltstone SE
Shale SH
Siltstone/Sandstone SL
Siltstone/Sandstone-Calcite vein-Sandstone SL-Ca-SD
Sandstone/Siltstone SS
Sandstone/Siltstone-Sandstone SS/SD
Siltstone ST
Shale/Sandstone SX
Individual coal samples (n=7)
NCLB068 NCLB068 Coal 1 Top Seam Coal
NCLB068 Coal 2 Top Seam Coal
NCLB068 Coal 3 Top Seam Coal
NCLB068 Coal 4 Top Seam Coal
NCLB068 Coal 5 Middle Seam Coal
NCLB068 Coal 6 Middle Seam Coal
NCLB068 Coal 7 Bottom Seam Coal
Composite Coal samples (n=2)
NCLB068 NCLB068 Coal Top, Middle and Bottom Seams Coal
NCLB047 NCLB047 Coal Bottom Seam Coal
Notes: 1. Dominant lithologies only included for composite samples (see APPENDIX B)
5.2 Chemical Properties 5.2.1 Acid-generating and neutralising potential
APPENDIX C (Table C1) provides a summary of the Acid Base Accounting (ABA) results for the Metsimaholo
samples only, collected as part of the previous New Vaal Lifex Project (Golder, 2013).
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Figure 6: Geochemical sample locations for Block 1, Vaalbank and Metsimaholo (Coalbrook) (Golder, 2013)
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Acidic paste pH was recorded for the same sandstone, mudstone/grit, carbonaceous mudstone and top seam
coal samples. These have sulphide sulphur concentration ranging between 0.12% and 0.83% and paste pH
varying from 4.5 to 5.8. The acidic paste pH indicates insufficient neutralising minerals to buffer the acidity generated by the sample in the short term. Neutral to alkaline paste pH were recorded in all the other
overburden/interburden and coal (middle and bottom seam) samples indicating the presence of reactive NP. The neutralising minerals contributing to the neutral pH are calcite, dolomite and aluminosilicates (See XRD
results, Figure C1 (APPENDIX C).
Figure 7: Paste pH vs sulphide S% for Metsimaholo (Golder, 2013)
It should be noted that the sulphide sulphur concentration constitutes at least 50% of total sulphur and that few
samples (<10) have total sulphur equivalent to sulphide concentration. Other form to sulphur include organic-S (predominant S form for coal and contact rock units), Elemental-S and Sulphate-S. The highest sulphide sulphur
concentrations were recorded in shale (1.7%), sandstone (0.01-2.3%), top seam coal (0.12-0.83%),
carbonaceous mudstone (0.005-0.59%), sandstone/siltstone (0.005-0.5%), carbonaceous shale (0.36%) and
siltstone/sandstone (0.005-0.31%).
Bulk NP ranged from 0.9 to 67 kgCaCO3/t and CaNP ranged from 0.7 to 107 kgCaCO3/t in the overburden/interburden samples. The bulk NP ranged from 5 to 58 kgCaCO3/t and carbonate NP ranged from
12 to 113 kgCaCO3/t in the coal samples and indicates that the samples have neutralisation potential to buffer
acid generation in the short-term.
Figure 8 shows that the CaNP of the overburden/interburden and coal samples is equal to the bulk NP in few
samples (<15) indicating that the NP is mainly from dissolving carbonates. The CaNP is greater than the bulk
NP in approximately 22 samples (including siltstone, carbonaceous mudstone and one of the coal lithological units) confirming presence of siderite. The remainder samples, mainly dolerite, have CaNP that is less than the
bulk NP indicating that NP is related to non- aluminosilicates.
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Figure 8: Carbonate NP versus bulk NP for Metsimaholo overburden/interburden and coals samples (Golder,2013)
Figure 9 reveals that fewer samples, including coal, siltstone, shale, grit-mudstone, carbonaceous mudstone
and sandstone have Sulphide AP greater than NP and thus have NPR less than 1. These samples (~22%) generally have sulphide sulphur concentrations > 0.3% and are likely acid generating in the short to long term.
The bulk of the samples have NP greater than AP, with most samples having NPR greater than 2.
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Figure 9: NP versus SAP for Metsimaholo overburden/interburden and coal samples (Golder, 2013)
5.2.1.1 ARD POTENTIAL
Classification of acid rock drainage (ARD) potential for the samples was based on guidelines as recommended by MEND (2009) (Table 2) and Price et al (1997).
Table 2: ARD assessment guidelines as provided by MEND (2009)
MEND (2009) * guidelines
Sample
Potential
Criteria Comments
PAG NPR<1 Potentially acid generating material, unless sulphide minerals are non-reactive, or NP is preferentially exposed on surfaces.
Non-PAG NPR>2 Non-potentially acid generation material, unless NP is insufficiently
reactive, extremely reactive sulphides are present, or preferential exposure of sulphides is found in the material.
Uncertain 1<NPR<2 Possibly PAG if NP is insufficiently reactive or is depleted at a faster rate than sulphides.
The potential for acid generation according to MEND (2009) based on sulphide S is indicated in Figure 10. The acid generating lithologies (~10%) in the Metsimaholo area are:
Grit-mudstone, which occurs mainly in the parting between the middle seam coal and the bottom seam coal close to the contact with coal;
Carbonaceous mudstone/shale, which occurs close to the contact with coal mainly in the inter-burden; and
Top seam coal.
Uncertain lithologies (~13%) include sandstone, sandstone-dolomite, siltstone, and shale-sandstone units.
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Figure 10: Paste pH versus SNPR for Metsimaholo overburden/interburden and coal samples.
The neutralisation potential for the samples is from fast reacting carbonate minerals (calcite and dolomite, APPENDIX C, Figure C1) resulting in average SNPR of 45 (SNPR range = 0.04 – 230). The high average SNPR
is consist with most of the samples (77%) being classified as Non PAG.
Kinetic results were conducted to confirm if the acidity in the uncertain samples would be released in the long term. Neutral to alkaline pH (7.2-9.3) during the 21 week kinetic test period was recorded due calcite mineral
buffering in the coal samples. It should be noted that kinetic testing of overburden/interburden uncertain and PAG lithologies (sandstone, shale, carbonaceous shale/mudstone, sandstone/siltstone) was not conducted to
confirm ARD and ML potential.
5.2.2 Net Acid Generation (NAG)
A plot of NAG pH against paste pH (selected composites) is shown in Figure 11. The overburden/interburden samples have slightly acidic to circumneutral NAG pH (5.9 - 6.6) indicating the presence of NP to buffer acidity generated by sulphide oxidation. The coal samples have acidic NAG pH of 2.3 and 3.9 (after complete oxidation)
indicating that there is insufficient neutralising minerals in the coal to buffer acid generation in the long term.
The NAG result implies that the overburden/interburden material is Non-PAG and the coal material is likely to generate acid mine drainage in the long term. Kinetic testing was conducted on coal composites to determine if
the acidity is realised in the long-term (Section 5.4).
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Figure 11: NAG pH versus Paste pH for Metsimaholo overburden/interburden and coal samples (Golder, 2013)
5.2.3 Metal Leaching
Short term leach using deionised water (1:4 ratio) indicated (Table 3) that the pH levels of the overburden/interburden (9.8-10) and coal (8.8-9.1) leachates are alkaline and implying the presence of reactive
NP to buffer acidity generated by the oxidation of sulphides. Leached concentrations of TDS (1 sandstone -
siltstone) NH3, F, Al, As, Pb and Se exceeded Class 0 (most stringent) drinking water guidelines. Arsenic (As), Ni and Se are commonly associated with pyrite present in the coal/overburden/interburden. These metals are expected to be leached from the material under alkaline field conditions. The TDS for the Vaal River is 600 mg/L
(DWAF, 1999) implying seepage/runoff from the WRD and coal stockpiles is expected to comply. Sulphate,
alkalinity and major metals (Ca, Mg, Na, K, Fe, Mn, and Si) contribute to the dissolved salt load.
Table 3: Summary of deionised water leach (S:L of 1:4) results (orange highlight indicate exceedance of Class 0&1)
Material type Overburden Composites Coal Composites
DWAF Domestic water quality
guidelines (1996)
DWAF (1999)
Parameter Unit SL-DO
MD-MC-SL
MD-ST
SL-SX-DO
MD-DO
ST-SL
DO-SD
SD-MD
Coal Coal
Borehole NCLB008
NCLB020
NCLB037
NCLB047
NCLB068
NCLB119
NCLB148
NCLB015
NCLB068
NCLB047
Class 0 Class 1
Vaal River
pH
10.1 10.0 10.1 10.0 10.1 9.9 9.8 10.1 9.1 8.8 6-9 4.5-10
EC ms/m 37 54 58 63 36 80 23 28 54 35 70 150
TDS mg/l 248 362 387 425 243 535 153 188 360 232 450 1000 600
NH3 as N mg/l 1.2 1.0 1.0 1.6 1.0 1.6 1.2 0.8 1.0 0.8 1 2
Alk (CaCO3)
mg/l 124 156 256 228 140 232 60 104 92 112 ng ng
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Material type Overburden Composites Coal Composites
DWAF Domestic water quality
guidelines (1996)
DWAF (1999)
Parameter Unit SL-DO
MD-MC-SL
MD-ST
SL-SX-DO
MD-DO
ST-SL
DO-SD
SD-MD
Coal Coal
Cl mg/l 8 18 8 6 16 2.5 2.5 8 20 11 100 200
SO4 mg/l 72 117 56 128 53 182 55 33 174 55 200 400
F mg/l 0.6 1.0 1.2 1.1 0.8 1.2 0.5 0.6 0.6 0.5 0.7 1
Al mg/l 1.6 1.8 2.4 1.9 1.7 2.3 2.3 1.6 1.4 2.3 0.15 0.5
As mg/l 0.099
0.049 0.10 0.07 0.058
0.061
0.19 0.035
0.019
<0.010
0.01 0.05
Ca mg/l 14 17 28 12 13 20 6.0 8.0 20 8.0 32 80
Cd mg/l <0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
0.003 0.005
Cr mg/l <0.025
<0.025
<0.025
<0.025
<0.025
<0.025
<0.025
<0.025
<0.025
<0.025
0.05 1
Cu mg/l 0.046
0.05 0.087
0.033
0.034
0.042
<0.025
0.026
0.099
<0.010
1 1.3
Fe mg/l 2.91 5.29 8.7 4.01 2.5 7.91 4.47 4.09 2.69 1.06 0.5 1
K mg/l 2.7 2.9 4.5 2.4 2.3 4.2 1.1 1.2 2.7 0.59 25 50
Mg mg/l 3.0 3.0 5.0 3.0 4.0 4.0 3.0 2.0 6.0 1.0 70 100
Mn mg/l 0.18 0.27 0.22 0.30 0.29 0.37 0.10 0.11 0.056
0.014
0.1 0.4
Na mg/l 94 143 172 159 90 211 50 68 85 88 100 200
Pb mg/l 0.021
0.034 0.061
0.027
0.023
0.065
0.01 0.01 0.026
0.010
0.01 0.05
Se mg/l 0.01 0.024 0.033
0.02 0.01 0.024
0.01 0.01 0.043
0.010
0.02 0.05
Si mg/l 5.5 8.9 12.9 6.9 6.8 10 4.7 4.8 3.9 4.9 ng ng
Zn mg/l <0.025
<0.025
<0.025
<0.025
<0.025
<0.025
<0.025
<0.025
<0.025
0.023
3 5
5.2.4 Peroxide leach
Table C2 (APPENDIX C) provides the Golder (2013) summary of the peroxide (1:100 solid to liquid ratio) for
the overburden/interburden and coal samples relative to SANS 241:2011 drinking water quality guidelines. The
results indicated that under acidic to circum neutral pH (pH 2.3 – 6.6) selected chemical constituents exceeded domestic water quality guidelines (DWAF, 1996) namely; Al, As, Cr, Fe, Mn, and NH3.
The NAG result implies that the overburden/interburden material is Non-PAG and the coal material is likely to
generate acid mine drainage in the long term. Kinetic testing was conducted to assess in the acidity is realised
in the coal material in the long-term (results in section 4.2).
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5.3 Additional ARD test work Golder (2013) conducted additional characterisation test work (ABA, NAG and SPLP 1:1 leach tests). Figure 12
and Figure 13) provides the descriptive statistics for the Metsimaholo ABA results roof and floor samples.
Figure 12: Box whisper plots (paste pH, Sulphide S, NP and NPR) for Metsimaholo roof samples (n=12)
Figure 13: Box whisper plots for pH and NP for Metsimaholo floor samples (n=10)
The ABA results indicate that the average paste pH of pH =8.67 and sulphide S concentration of Sulp S= 0.17% for the roof samples (Figure 12). Three roof samples namely (NCLB047-09 -0.65%, NCLB008-6 -0.35%, NCLB119-13-0.27% and NCLB 037-7-0.26% has sulphide S ≥0.3% indicating potential ARD risk depending on
reactive NP minerals present in the samples to buffer acidity generated from sulphide oxidation.
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Figure 14: Plot of Paste pH vs Sulphide S for Metsimaholo roof material
The average NP was recorded as 21 kg CaCO3 eqv/ton indicating available neutralisation potential from carbonates. Figure 15 indicates that five samples have NPR>2 and are Non PAG. Five (5) roof samples have
NPR 1-2 or NPR <1 and sulphide S <0.0.2 classifying as Non PAG.
Figure 15: Plot of NP vs SAP for Metsimaholo roof material
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Based on ABA classification, ~ 17% of the roof samples are classified as likely acid generation and will contribute
acidity and ARD products on oxidation and dissolution with groundwater inflows. Under full oxidation all roof
sample are acid generating based on NAG pH <4.5 (Figure 16, Append E provides the NAG leach results).
Figure 16: NAG pH for Metsimaholo roof samples
Acid Base Accounting (ABA) results for the floor samples indicate that the average paste pH and sulphide S
concentration is pH =7.79 (Figure 13) and Sulp S= 0.16% (Figure 17). The average NP was recorded as 14 kg
CaCO3 eqv/ton indicating limited carbonate neutralisation potential available. Figure 18 indicates that four (4) samples have NPR>2, implying Non-PAG classification. Four (4) samples have NPR 1-2 or NPR <1, and
sulphide S >0.1 %, classifying as likely acid generation. Therefore ~ 40% of the floor material is expected to be
PAG.
Under full oxidation all floor sample are acid generating based on NAG pH <4.5 (APPENDIX E provides the
NAG leach results for the floor materials).
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Figure 17: Plot of Paste pH vs Sulphide S for Metsimaholo floor material
Figure 18: Plot of NP vs SAP for Metsimaholo floor material
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5.3.1 Roof and Floor Metal Leaching
Leach results of the roof and floor materials is indicated in Table 4 indicate that the following chemical constituents are identified as potential constituent of concern (PCoCs) in the UGM water: pH (acidic), EC, TDS,
NH3, NO3, SO4, F, Al, As, Ca, Cu, Fe, Mg, Mn and Na.
Table 4: Summary of deionised water leach (S:L 1:1) results for Metsimaholo roof & floor samples
Chemical Constituents*
NCLB Roof (n=12) NCLB Floor (n=10) DWAF (1996) domestic water quality
DWAF (2009)
Percentile/class/river system
5TH 50TH 95TH 5TH 50TH 95TH Class 0 Class 1 Vaal River
pH 9.6 8.9 4.5 8.9 7.6 3.5 6-9 4.5-10 ng
EC 20 56 362 33 115 442 70 150 ng
TDS 141 375 3196 219 674 3610 450 1000 600
NH3 as N 0.24 0.5 1.7 0.34 0.55 2.0 1 2 ng
Alk (CaCO3) 38 80 118 16 70 103 ng ng ng
NO3 as N 0.72 1.8 3.7 1.0 4.2 7.3 6 10 ng
Cl 5 6 24 5.0 6.0 9.8 100 200 ng
SO4 28 180 2249 73 487 2549 200 400 ng
F 0.2 0.7 2.1 0.20 0.60 1.8 0.7 1 ng
Al 2.2 7.7 19 0.46 3.5 17 0.15 0.5 ng
As 0.025 0.050 0.17 0.020 0.030 0.18 0.01 0.05 ng
B 0.066 0.36 0.59 0.073 0.32 0.97 ng ng ng
Ca 0.065 1.7 192 0.16 7.8 43 32 80 ng
Cd <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 0.003 0.005 ng
Co 0.013 0.29 3.1 0.020 0.15 3.1 ng ng ng
Cr 0.010 0.010 0.14 0.010 0.010 0.15 0.05 1 ng
Cu 0.010 0.010 1.5 0.012 0.035 1.5 1 1.3 ng
Fe 0.60 1.4 17 0.096 1.2 13 0.5 1 ng
K 0.78 2.2 3.7 0.52 1.8 3.8 25 50 ng
Mg 0.95 1.7 133 0.60 2.5 24 70 100 ng
Mn 0.033 0.057 23 0.033 0.078 5.6 0.1 0.4 ng
Mo 0.041 0.11 0.16 0.014 0.072 0.28 ng ng ng
Na 50 116 580 60 130 677 100 200 ng
Ni 0.011 0.031 6.3 0.0177 0.0796 6.62 ng ng ng
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Chemical Constituents*
NCLB Roof (n=12) NCLB Floor (n=10) DWAF (1996) domestic water quality
DWAF (2009)
Pb <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 0.01 0.05 ng
Se 0.010 0.034 0.075 0.011 0.040 0.064 0.02 0.05 ng
Si 4.8 27 43 4.7 14 32 ng ng ng
Zn 0.018 0.11 2.1 0.016 0.11 2.2 3 5 ng
Note:* all units in mg/l unless standard units. orange /red highlight indicate exceedance to 2/3 water quality criteria values
5.4 Kinetic Test work Table 5 provides the composition of the samples subjected to kinetic testing (Humidity Cell - HC method) for Lifex project. Since no overburden/interburden samples were setup for Metsimaholo, the Vaalbank composites
(Figure 6) were used of analogues to assess the metal leaching composition in the long term. APPENDIX D provides the Metsimaholo coal composites kinetic results and Vaal Bank summary graphs for the
interburden/overburden composites.
Table 5: Humidity cell setup composite samples for Vaalbank, Metsimaholo and New Vaal mine blocks
Material type Borehole Humidity Cell Name Dominant lithology Lith code
Vaalbank
Overburden/ Interburden Composite
NVL0015 NVL0015/01-10 COMP Sandstone-Mudstone SD-MD
NVL0017 NVL0017/01-11 COMP Sandstone/siltstone-Mudstone SS-MD
New Vaal/Block 1
WRTM4 WRTM4 Mudstone-Siltstone MD-ST
WRTM5 WRTM5 Mudstone-Siltstone MD-ST
Coal Composite Vaalbank
NVL0015 NVL0015 Coal/01-02 Top seam (47%) Coal TS-MS
Middle seam (53%)
NVL0021 NVL0021 Coal-01 Middle seam (100%) Coal MS
NVL90057 NVL90057 Coal/01-02 Top seam (72%) Coal TS-MS
Middle seam (28%)
Metsimaholo
NCLB047 NCLB047 Coal/01-02 Middle seam (50%) Coal MS-BS
Bottom seam (50%)
NCLB068 NCLB068 Coal/01-07 Top seam (24%) Coal TS-MS-BS
Middle seam (53%)
Bottom seam (23%)
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5.4.1 Particle Size Distribution
Particle size distribution (PSD) was assessed in overburden HC samples WRTM4 and WRTM 5 (Figure 19).
The particles sizes in the humidity cell (HC) composite samples ranged in size from <0.053 mm (silt) to 2.8 mm
(fine gravel). The highest proportion (59%) are sand sized particles (0.6-2mm), followed by fine gravel (31%).
Figure 19: Particle size distribution for New Vaal Colliery Humidity cell samples, WRTM4 and WRTM5
Studies by Van Nierkerk (1997) revealed that particle sizes less than 2mm (sand to clay) constitutes 10-50% of
particle sizes in South African coal spoils. The HC PSD is almost representative of a fraction that will be reactive
in overburden/interburden waste rock reporting to designated WRD. The variation in particle sizes was further assessed by computing the coefficient of uniformity and coefficient of curvature for the two samples. Golder found that the sand and gravel PSD indicated that the material has a wide variation in particle size (well graded).
Well graded materials will tend to compact to a lower porosity (and hence reduce permeability) than uniformly graded materials. This could affect the rate of rainfall recharge and oxygen supply into overburden/interburden
and consequently seepage volume and quantity.
5.4.2 Mineralogical Composition
Mineralogical composition of overburden/interburden/parting and coal humidity cell samples is presented in
Figure 20.
Quartz (51-68%) is the dominant mineral in overburden/interburden/parting while kaolinite (52-84%) was
dominant in coal samples. (Figure 20).
Pyrite was detected as a minor to trace phase in selected coal and in one overburden/interburden/parting sample (WRTM 5). Alunite was detected in one of the coal samples suggesting oxidation of sulphides prior to
kinetic tests. This mineral is likely to influence concentration of SO4 and K in initial drainage from the HC containing the coal sample (NVL90015). No sulphides were noted in this sample suggesting that pyrite was probably present at concentrations that were below the XRD analytical method detection limit.
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Dissolving carbonates were detected in four of the five coal samples indicating available NP to buffer acid
generated from sulphide oxidation. The only carbonate that was detected in overburden/interburden/parting samples is siderite. However, siderite does not have net NP under oxidising conditions that are likely to prevail
in overburden/interburden materials under field conditions.
Figure 20: Mineralogical composition of HC samples
5.4.3 Acid Base Accounting
The ABA results of the HC samples are presented in Table 6 and indicated that the paste pH of both the overburden/interburden/parting and coal samples was alkaline (7.4-8.8).This is attributed to dissolved
carbonates, which buffers acidity up to a pH value of 11.
Neutralisation potential varied between 7.0 and 33 kgCaCO3/ton in the HC samples. Generally, the coal samples
have higher NP values compared to overburden/interburden/parting samples and are attributed to presence of
dissolving carbonate minerals (Figure 20).
Table 6: Summary of ABA results for HC composite samples
Sample ID Material
Type
Rock
Type
Paste
pH
Total
S
Sulphide
S
TAP SAP BULK
NP
SNPR Classifica
tion
s.u % kg CaCO3 eqv/ton no units
NVL90015 Overburden/
interburden
SD-MD-
DO
8.0 0.35 0.17 11 5.3 7.0 1.3 Uncertain
NVL90017 SS-MD 7.7 0.47 0.22 15 6.9 9.1 1.3
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Sample ID Material
Type
Rock
Type
Paste
pH
Total
S
Sulphide
S
TAP SAP BULK
NP
SNPR Classifica
tion
s.u % kg CaCO3 eqv/ton no units
WRTM 4 Overburden/
interburden/
parting
MD-ST 7.4 0.34 0.15 11 4.7 21 4.5 Non PAG
WRTM 5 MD-ST 7.8 0.32 0.14 10 4.4 17 3.9
NVL90015 Coal Coal 8.8 0.23 0.10 7.1 3.2 14 4.4 Non PAG
NVL90021 Coal Coal 8.1 0.25 0.04 7.8 1.3 16 12 Non PAG
NVL90057 Coal Coal 8.5 0.23 0.31 7.2 9.7 7.9 0.81 PAG
NCLB047 Coal Coal 8.2 1.5 0.14 47 4.4 32 7.3 Non PAG
NCLB068 Coal Coal 8.4 0.88 0.53 28 17 33 2.0 Non PAG
Figure 21 indicates the sulphide sulphur range for the HC composite samples and that sulphide S ≤ Total S in
all but one sample indicating presence of other sulphur species. This implies that total sulphur would overestimate AP. Based on SNPR two overburden samples (NVL0015 and NVL90017) classifies as Uncertain
according to MEND (2009) criteria (Table 2).
Figure 21: New Vaal Lifex HC samples (Golder, 2013)
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5.4.4 Kinetic Test Results
The long-term drainage pH conditions was assessed in the humidity cells over a 21-week period and the results are presented in APPENDIX D. The following inferences are made from the Metsimaholo and Vaalbank kinetic
results (Figure 22 and Figure 23):
Coal
The average pH after a 21-week cycle was 7.9. The pH in the coal samples varied from neutral to alkaline (7.2-9.3) during test period and is attributed to the presence of calcite in Metsimaholo coal;
The Metsimaholo top and middle coal seams recorded the highest TDS concentrations (1160 mg/l); and
Salinity in the overburden/interburden (Figure 23) and coal samples was mainly from alkalinity, Ca, Fe, K, Mg, Na, Si and SO4. This is consistent with the short-term leach test results (Table 3).
Figure 22: Kinetic results for pH, EC and sulphate for Metsimaholo coal composites
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Figure 23: Kinetic results for pH, EC and sulphate Vaalbank overburden/interburden composites
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Overburden/Interburden (Figure 23)
The average pH of all the leachate after a 21 week cycle was 5.8 with the weekly leach pH ranging from acidic to alkaline (4.3-8.0) during test period;
The first flush leachate quality was acidic in the Vaalbank sandstone-mudstone (pH=5.8) and is attributed to pre-existing oxidation of pyrite (1-2%) in these samples. The sandstone/siltstone composite was recorded with week 0 pH = 4.3;
The near neutral pH (pH = 6.3-8.0) in the New Vaal Colliery mudstone-siltstone samples is attributed to the dissolution of calcium/magnesium carbonate minerals;
The final week pH (week 21) in the sandstone-mudstone and mudstone-siltstone samples was circum-neutral (6.4- 6.9); and
The TDS ranged from 51 to 2905 mg/l in the overburden/interburden samples and 32 to 1160 mg/l in coal samples. Vaalbank hard overburden/interburden and inter-burden material recorded the highest TDS values (2905 mg/l).
5.5 Propensity for spontaneous combustion Coal and coal discard material is known to have a risk of spontaneous combustion, due to exothermic ARD reactions (heat is generated during the oxidation of pyrite) and from the heat of rewetting of dry or oxidised pyrite. No discard material will be generated since no washing/processing plant is planned since the coal from
the mining section will be hauled and tipped into surface silo’s ready for distribution (4.0).
5.6 Toxicity No information of the following aquatic toxicity tests on WRD overburden/ interburden material and dewatered
UGM mine quality. Therefore, ecotoxicological testing is recommended for surface drainage (toe seep) and
decant water samples.
5.7 Physical properties Bulk material sample test work has not been completed for the WRD and should form part of the engineering
design work. Information is not currently available on the following physical properties of the discard:
PSD;
Water retention;
Moisture content;
Settling behaviour;
Void ratios; and
Strength.
6.0 RISK ASSESSMENT Regulation 5 of GN R. 632 of 2015, as amended by GN 990 of 21 September 2018, requires that a risk assessment of the proposed mine residue facility be conducted. In the case of the current application, this is a
risk assessment for the expanded discard dump. Based upon the requirements of Regulation 9, Golder has
developed a transdisciplinary framework for mining residue facility environmental risk assessment (Figure
24).The framework includes:
1) Characterisation of the mining residue waste streams in terms of Regulation 4:
a) Geochemical characteristics,
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b) Physical characteristics, and
c) Toxicity,
2) Aggregation and integration of the mining residue characterisation into the profile of the completed MRF;
3) Determination – using the source-pathway-receptor modelling approach – of the impact on the receiving groundwater and surface water environment, considering:
a) The characterisation of the mining residues,
b) The vulnerability of the local aquifer(s),
c) The presence of vulnerable ecosystems, and
The predicted runoff and seepage chemistry, with classification of the predicted mine water in terms of baseline water quality, DWAF (1996) water use guidelines and the water quality planning limits (WQPL) applicable to the receiving water bodies;
4) Determination of the impact on biodiversity based upon the impact on groundwater and surface water;
5) Prevention of pollution in order to satisfactorily mitigate the impact on groundwater and surface water and on biodiversity, such prevention measures to potentially include:
a) The minimisation of runoff and seepage – e.g. through dewatering and compaction,
b) The interception of runoff and seepage – this is the pollution control barrier system, which may be a:
- Physical barrier like a liner or stormwater berm, or
- Pressure barrier created in groundwater by a pumping well, prevents groundwater flow and decant, and
c) The reuse or treatment and release of intercepted mine waters.
According to GN R. 632 of 2015 (Regulation 1, GN 990 of 21 September 2018), the risk assessment should be
completed by a geochemist and a hydrogeologist and signed off by a competent person.
Figure 24: Flowchart for mining residue facility environmental risk assessment in terms of GN R. 632 of 2015
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6.1 Preliminary risk assessment for WRD It is understood that minimal waste rock materials will be generated from the development of the decline,
perimeter and galleries for the proposed UGM and be placed in the designated WRD (Figure 3).
Precipitation falling on the WRD will evaporate, flow over the surface of the pile as runoff or infiltrate into the
pile. Saturated conditions may develop within the WRD and there may be development of a perched water table at the base of the pile if the layer underlying the facility is of a low permeability. Seepage may exit either from
the slope face or toe of the WRD or it may infiltrate the subsurface beneath the pile.
The overburden and interburden material comprising WRD will be a mixture of carbonaceous and non-
carbonaceous rock units namely, sandstone, grit, mudstone, siltstone and dolerite. The following potential risks
are identified for the proposed WRD:
Acid generation and neutralisation potential characteristics is summarised in Table 7. Some lithological units reporting to the proposed WRD namely grit, mudstone, carbonaceous mudstone/shale was found to be acid generating (PAG) based on SNPR. The volume of PAG and Non-PAG material reporting to WRD
need to be confirmed by the geological model; and
Circum- neutral runoff / seepage with low to moderate salinity and metal concentrations is expected for the WRD. Mildly acidic runoff and seepage can occur after the dry season i.e. first flush resulting that could
exceed water quality criteria. The following chemical constituents were found to exceed DWAF (1996)
drinking water (Class0-1) guidelines: pH (alkaline), Al, As, Pb, Se and NO3.
Table 7: Summary of characterisation results for Metsimaholo coal and inter-burden/overburden samples
Metsimaholo Licence area
Test parameter Characteristics results
Metsimaholo overburden/ interburden (n=62)
Paste pH The paste pH is acidic to alkaline (4.6-10). Acidic paste pH was recorded in grit-mudstone (5.8), carbonaceous mudstone (5.0 to 8.5) and sandstone (4.6-9.7) constituting mainly the inter-burden material.
Sulphur % The total sulphur and sulphide sulphur content ranges from 0.01 to 2.6% and <0.01 to 1.7%, respectively.
Neutralising potential
The Sobek ranges from 0.9 to 67 kgCaCO3/t.
ARD Classification*
The samples predominantly classify as Non-PAG (90%). The Non-PAG units include dolerite, mudstone, shale/sandstone, siltstone, sandstone (non-carbonaceous), sandstone/siltstone (non-carbonaceous) and shale/siltstone (non-carbonaceous).
The PAG (4.5%) unit and Uncertain (6.0%) units include Grit-mudstone which occurs mainly in the parting between the middle seam coal and the bottom seam coal close to the contact with coal and Carbonaceous mudstone/shale which occurs close to the contact with coal mainly in the inter-burden.
Short-term leach pH, TDS (1 sample), NH3, Al, As, Pb and Se exceeded DWAF (1996) Class0-1
NAG The NAG pH ranged from 5.9 to 6.6. One of the seven samples (siltstone/sandstone-dolerite) classifies as ‘uncertain’.
Metsimaholo Coal (n=9)
Paste PH Paste pH is acidic pH (5.1 to 6.3).
Sulphur (%) The total sulphur and sulphide sulphur concentration ranges from 0.05 to 1.5% and 0.04 to 0.53% respectively.
Neutralisation potential
Total NP ranges from 5 to 58 kgCaCO3/t.
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Metsimaholo Licence area
Test parameter Characteristics results
ARD classification* The top seam coal samples (two samples, 22%) classify PAG.
Short-term leach Al, As, Pb and Se exceeded DWAF (1996) Class0-1.
NAG The NAG pH ranged from 2.3 to 3.9 (both samples PAG).
Notes: *ARD classification according to MEND (2009) and is based on sulphide S (Sulphide Neutralising Potential Ratio SNPR)
PAG=potentially acid generating Non-PAG=not potentially acid generating Uncertain= uncertain whether it is potentially acid generating or
not potentially acid generating n=Total number of samples analysed
No kinetic tests were conducted for Metsimaholo overburden/interburden material. Therefore, the overburden/interburden from Vaalbank was deemed as fair analogue for Metsimaholo material. The initial leachate (after first flush) pH in three (3) of the four (4) overburden humidity cells leachate was acidic (5.1-
5.8) while the final leachate (week 20) pH varied between 6.1 and 6.9. The near neutral leachate pH
indicates buffering by carbonates;
Humidity cells with overburden composites from Vaalbank (NVL 90015 COMP and NVL 90017 COMP) had higher SO4 concentrations (85-1482 mg/l) than overburden humidity cells from New Vaal Colliery (31-
350 mg/l);
Spontaneous combustion of coal remnants and carbonaceous material is expected for the WRD; and
Although the volume of coal and carbonaceous material is expected to be low in comparison to the non- carbonaceous material, coal/carbonaceous material will combust due to pyrite oxidation and thermal
gradients within the dump.
6.2 Preliminary risk assessment for Underground Mine Underground mining could expose reactive sulphides which potentially occur in the roof, floor, hanging wall, footwall and blast fractures to atmospheric oxygen that enters the underground workings via declines and
ventilation shafts. Therefore, the Golder (2013) additional data, has subsequently been used for the UGM risk
assessment.
The primary mineral composition of the hanging wall roof is expected to be the remnant coal from the top/middle coal seams. The floor is expected to be carbonaceous interburden in contact with the bottom coal seams (to be
confirmed by mine planning model).
The geochemical characterisation of individual rock units from the NVC Lifex and Metsimaholo project areas indicated that rock units that occur in close contact with the different coal seams are generally PAG. These units
include grit, carbonaceous shale, carbonaceous mudstone, siltstone and sandstone (Table 7). Coal composites
(NCLB068 and NCLB047) classified as PAG under fully oxidised condition (NAG pH = 2.3-3.9).
The following conclusion are made for the proposed Metsimaholo UGM roof and floor acid generation potential:
UGM Roof
The ABA results indicate that the average paste pH of pH =8.67 and sulphide S concentration of Sulp S= 0.17% for the roof samples. The average NP was recorded as 21 kg CaCO3 eqv/ton indicating available neutralisation
potential from carbonates. Five (5) classified as uncertain with SNPR 1-2 or PAG SNPR <1 (Figure 15).
Based on ABA classification, ~ 17% of the roof samples are classified as PAG and will contribute acidity and
salinity to clean groundwater inflows. Under full oxidation all roof sample are acid generating based on NAG pH
<4.5 (Figure 16).
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UGM Floor
Acid Base Accounting (ABA) results for the floor samples indicate that the average paste pH and sulphide S concentration is pH =7.79 and Sulp S= 0.16%. The average NP was recorded as 14 kg CaCO3 eqv/ton indicating
limited carbonate NP available to buffer acidity ~ 40% of the floor material is expected to be PAG (Figure 18).
Under full oxidation, all floor sample are acid generating based on NAG pH <4.5 (Append E provides the NAG
leach results for the floor materials).
During operation, continuous decanting of the ingress water (infiltrating water) takes place; due to the absence
of flooding waters in the mined-out voids the surrounding walls and pillars gets oxidised. This implies that the
mine water during operational phase and discharge /decant water from the underground workings could require
treatment according to the quality of the discharge.
The quality of underground mine water is typically dependant on one or more of the following factors:
Aquifer and inter-mine flow in the mine workings;
Surface water recharge to the mine workings through shafts and fractures;
The mine flooding/dewatering regime;
Thermal convection in mine cavities, which may result in density variations (due to temperature differences
and/or salinity stratification) between downward circulating and upwelling water;
The presence of bacteria such as Thiobacillus ferrooxidans which occur in many sulphide-rich mineral
environments and are capable of catalysing reaction rates by orders of magnitude;
Geological structures affecting water flow within the mine workings. These may include stress fractures, which commonly develop in and around the mining horizon through blasting or rock pressure. These fractures can add significant reactive surface area to the mine void system and may increase contaminant
loads by an order of magnitude relative to those that would be generated on unfractured mine wall surfaces;
and
The grain morphology of the various reactive rocks and minerals. The grain size of a mineral or rock particle is indirectly proportional to its exposed surface area which is available to react with oxygen (in the case of sulphide oxidation) or dissolved acid species in solution (in the case of neutralising minerals). This, in turn
influences reaction rate, thereby affecting water quality.
The formation of secondary minerals (e.g. hematite and ferric oxyhydroxides such as goethite and lepidocrocite)
as by-products of sulphide oxidation and acid neutralisation reactions. Their formation is common in mines which have been dewatered for extended time periods. These minerals act as stores of acidity and/or salinity, which are released upon exposure to water. It is thus common for the majority of these salts to accumulate in
the mine workings during mining, with a fraction being leached into the water that is moving through the workings. Upon cessation of dewatering, the salts are released into the water that floods the mine. These salts, whether accumulated on walls (including the roof and floor) or in cracks, will determine the post-closure water
quality of the system.
Leach results of the roof and floor materials indicates that the following (PCoCs) in the UGM water: pH (acidic),
EC, TDS, NH3, NO3, SO4, F, Al, As, Ca, Cu, Fe, Mg, Mn and Na.
7.0 CONCLUSIONS AND RECOMMENDATIONS In conclusion, the Metsimaholo geochemical characterisation results from the New Vaal Lifex EIA study has
enabled an initial understanding of the ARD and ML potential of the various geological materials generated by
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Metsimaholo Colliery to be developed. Furthermore, ARD and ML risks associated with the handling and
stockpiling of coal and carbonaceous overburden (hard) waste rock in contact with the top coal seam have been identified as high risk (ARD/ML) materials that could impact the receiving environment. The proposed UGM will have localised areas of ARD and ML based on the 17-40% PAG classification of the roof and floor materials
respectively.
The following recommendations are made for subsequent geochemistry specialist studies as part of the
proposed Metsimaholo Colliery development:
An understanding of the various lithological units comprising the roof and floor (per level/seam) is required.
Remnant coal material is expected to be the roof and floor for the top seam (classified as potentially acid
generating), whereas the parting and bottom seam will comprise the floor (remnant coal will comprise the roof) of the middle seam. Further characterisation and and material property test work for the UGM roof
and floor material is recommended.
Representative samples of roof and floor materials within the mine blocks should be collected and
characterised (static test work) to developed and update the Metsimaholo geochemical database. The
detailed geochemical sampling and characterisation programme should be conducted to identify of localised hotspot area(s) and the ratio of acid potential and availability of NP such that the results can be
included in the geological block model;
Kinetic tests are required for uncertain and PAG overburden/interburden lithologies (top/middle and bottom
coal seam, sandstone-shale, carbonaceous shale/mudstone, sandstone/siltstone) to confirm neutralisation
depletion rates and if acidity (from sulphide oxidation) will be realised in the long-term;
The ratios/volume of the carbonaceous material (coal, and siltstone/sandstone/mudstone roof) to hard/soft overburden needs to be understood from the mine planning to guide the design and placement of the WRD
comprising of development/ shaft rock units;
Ecotoxicology test work is recommended as part of the characterisation, to assess the toxicity of the WRD
seepage /runoff and UGM mine water quality namely:
Vibrio fischeri screening;
Selenastrum capricornutum screening;
Daphnia pulex screening; and
Poecilia reticulata screening.
The Metsimaholo geochemical database should be used to support UGM quality predictions that is required to quantify impacts as part of the groundwater contaminant transport model (Golder, 2018) and
assess treatment requirements;
Confirmatory monitoring of carbonaceous overburden/interburben material reporting to the WRD should
be done on an annual basis as part of the ARD monitoring. This monitoring should include:
Sampling of siltstone/shale/sandstone/mudstone waste rock to confirm the exceeds NP;
Analysis of samples for standard Acid Base Accounting ( including sulphur speciation);
Data basing of results, preferably in the geological model; and
Water quality monitoring of toe seepage/ponded water from the WRD and UGM water dams/standing
water, in addition to standard dewatering quality).
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The above monitoring data is critical to update the mine wide salt balance and future geochemical
modelling work (long term post closure) predictions.
Conduct field testing of material geochemical and geohydraulic properties e.g. construction field humidity
cells of carbonaceous rock units (roof and floor material) not earmarked be mined, to obtain site-specific
drainage quality data under field conditions. Field cells (open 100l polyurethane drums fitted with seepage
containers) should be monitored for seepage rates and qualities; and
Develop an ARD/ML management plan for the site based on the geochemical characterisation, monitoring, mine planning and closure planning of the mine site. This document will be a dynamic document that acts
as a planning tool (contains actions etc) and also interlinks with the site water management and closure
plans.
8.0 REFERENCES DWAF, 2009. The Development of an Integrated Water Quality Management Plan (IWQMP) for the VaalRiver
System Report No.: 36 P RSA C000/00/2305/7, September 1999
International Network for Acid Prevention (INAP), 2012. Global Acid Rock Drainage (GARD) Guide,
www.gardguide.com (30 April 2013).
Golder, 2010. New Vaal Life Expansion Groundwater Baseline Study, Report No. 12111-9878-6, July 2010
Golder, 2013. New Vaal Colliery Life Extension Project - Specialist Geochemistry Study. Report Number 11211-
11362-2, May 2013
MEND, 2009. Prediction Manual for Drainage Chemistry from Sulphidic Geological Materials. Mine Environment
Neutral Drainage Program (MEND) Report 1.20.1,British Columbia, Canada.
Miller S., Robertson, A. and Donohue, T. 1997. Advances in Acid Drainage Prediction using the Net Acid
Generation (NAG) Test. In: Proceedings of the Fourth International Conference on Acid Rock Drainage,
Vancouver, British Columbia, May 31-June 6. Volume 2. Pages 533-547.
Price W.A., Morin K., Hutt N. 1997. Guidelines for prediction of acid rock drainage and metal leaching for mines in British Columbia: Part II. Recommended procedures for static and kinetic tests. In: Proceedings of the Fourth
International Conference on Acid Rock Drainage. Vancouver, B.C. Canada, 1, pp15–30.
Van Niekerk A. M., 1997. Generic Simulation Model for Opencast Mine Water Systems. WRC Report No.
528/1/97.
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Signature Page
Golder Associates Africa (Pty) Ltd.
K. Naicker D. Love
Associate Technical Director
KN/DL/CK
Reg. No. 2002/007104/07
Directors: RGM Heath, MQ Mokulubete, SC Naidoo, GYW Ngoma Golder and the G logo are trademarks of Golder Associates Corporation
g:\projects\18101804 - seritinewvaal ncvmra\6. deliverables\drafts\specialists\geochem\final for public review\18101804_metsimaholo_geochem_v4_2019.03.28.docx
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APPENDIX A
Mine design
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Figure A1: New Vaal MLH: Mine Design Map
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Figure A2: New Vaal TMH: Mine Design Map
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APPENDIX B
Borehole logs and geochemical samples
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Table B1 Geochemical samples (Golder, 2013)
Borehole Sample Name Dominant Lithology1 Lith Code1
NCLB037 NCLB037/01‐09 Mudstone‐Siltstone MD‐ST
NCLB119 NCLB119/01‐13 Siltstone‐Siltstone/Sandstone ST‐SL
NCLB047 NCLB047/01‐10 Siltstone/Sandstone‐Shale/Sandstone‐Dolerite SL‐SX‐DO
NCLB020 NCLB020/01‐10 Mudstone‐Carbonaceous Mudstone‐Siltstone/Sandstone MD‐MC‐SL
NCLB008 NCLB008/01‐08 Siltstone/Sandstone‐Dolerite SL‐DO
NCLB148 NCLB148/01‐08 Dolerite‐Sandstone DO‐SD
NCLB068 NCLB068/01‐12 Mudstone‐Dolerite MD‐DO
NCLB151 NCLB151/01‐08 Dolerite‐Siltstone/Sandstone DO/SL
NCLB037 Carbonaceous Shale CS
NCLB119 Dolerite DO
NCLB047 Dolerite‐Sandstone DO/SD
NCLB020 Grit‐Mudstone GR/MD
NCLB008 Gritstone GS
NCLB148 Carbonaceous Mudstone MC
NCLB068 Mudstone‐Sandstone MD/SD
NCLB151 Sandstone SD
NCLB020 Sandstone‐Sandstone/Shale SD/SX
Shale‐Siltstone SE
Shale SH
Siltstone/Sandstone SL
Siltstone/Sandstone‐Calcite‐Sandstone SL/Ca/SD
Sanstone/Siltstone SS
Sanstone/Siltstone‐Sandstone SS/SD
Siltstone ST
Shale/Sandstone SX
NCLB068 NCLB068 Coal 1 Top Seam Coal
NCLB068 Coal 2 Top Seam Coal
NCLB068 Coal 3 Top Seam Coal
NCLB068 Coal 4 Top Seam Coal
NCLB068 Coal 5 Middle Seam Coal
NCLB068 Coal 6 Middle Seam Coal
NCLB068 Coal 7 Bottom Seam Coal
NCLB068 NCLB068 Coal Top, Middle and Bottom Seams Coal
NCLB047 NCLB047 Coal Bottom Seam Coal
Overburden Composite Samples (n=8)
See borehole logs
Overburden Individual Samples
Individual coal samples
Composite Coal samples
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APPENDIX C
Static results summary
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Table C1: ABA Summary (Golder, 2013)
Coalbrook Paste pH Total carbon Carbonate Total sulphur Sulphide sulphur Sulphate sulphur SAP2 TAP2 BULK NP4 Carbonate NP3 SNNP5 TNNP5 SNPR6 TNPR6
Units s.u %C % CO3 %S %S-2 %
Limit of detection <0.05 <0.01 <0.01 <0.03
N 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Absolute value 8.7 3.7 0.08 0.55 0.36 0.57 11.3 17.2 12.0 1.3 0.8 ‐5.2 1.1 0.7
N 9 9 9 9 9 9 9.0 9.0 9 9.0 9 9 9 9
5th Percentile 8.56 0.02 0.039 0.014 0.005 0.021 0.2 0.4 13 0.7 13 12 18 8
Median 9.4 0.17 0.42 0.04 0.01 0.09 0.3 1.3 19 7.0 17 17 96 21
95th Percentile 10.1 1.49 2.9 0.08 0.038 0.194 1.2 2.5 66 48.4 66 64 228 54
N 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Absolute value 5.8 4.6 0.44 0.25 0.19 0.19 5.9 7.8 5.7 7.3 ‐0.2 ‐2.1 1.0 0.7
N 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Absolute value 8.4 3.3 0.27 0.005 0.005 0.015 0.2 0.2 1.5 4.5 1.3 1.3 9.6 9.6
N 4 4 4 4 4 4 4 4 4 4 4 4 4 4
5th 4.995 2.02 0.1655 0.0115 0.00575 0.02025 0.2 0.4 0.9 2.8 ‐14.8 ‐23.6 2.0 1.7
Median 7.95 5.4 0.45 0.075 0.045 0.1 1.4 2.3 8.1 7.5 7.8 7.6 15.6 12.1
95th 8.525 6.74 2.2135 0.8015 0.5135 0.8725 16.0 25.0 40.1 36.9 37.9 36.5 68.0 18.3
N 6 6 6 6 6 6 6 6 6 6 6 6 6 6
5th 8.5 0.12 0.15375 0.00875 0.005 0.01875 0.2 0.3 14.3 2.6 12.8 8.3 9.7 2.5
Median 8.95 1.35 0.73 0.06 0.015 0.125 0.5 1.9 15.5 12.2 15.3 14.5 40.0 9.1
95th 9.525 5.15 0.8575 0.19 0.0475 0.4125 1.5 5.9 17.8 14.3 17.2 16.3 105.6 78.8
N 8 8 8 8 8 8 8 8 8 8 8 8 8 8
5th 4.615 0.259 0.2375 0.0235 0.0135 0.015 0.4 0.7 4.4 4 ‐42.6 ‐70.6 0.5 0.2
Median 8.3 2.1 1.15 0.09 0.035 0.17 1.1 2.8 18.3 19 12.2 8.9 18.5 8.3
95th 9.665 5.18 2.615 2.64 1.7225 2.695 53.8 82.5 45.8 44 44.8 43.4 48.8 27.9
N 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Absolute value 9.5 2.5 0.75 0.005 0.005 0.015 0 0 16.6 13 16.4 16.4 106.2 106
N 1 1 1 1 1 1 1 1 1 1 1 1 1 1
SH 9.3 3.9 0.54 3 1.7 3.9 53.1 93.8 11.4 9 ‐41.7 ‐82.4 0.2 0.1
N 7 7 7 7 7 7 7.0 7.0 7.0 7 7.0 7.0 7.0 7.0
5th 7.86 0.623 0.599 0.005 0.005 0.015 0.2 0.2 8.0 10 7.8 6.7 3.2 2.6
Median 8.3 1.1 1.1 0.03 0.005 0.015 0.2 0.9 17.0 18 12.1 11.8 45.4 18.1
95th 9.18 9.65 1.74 0.328 0.241 0.282 7.5 10.3 23.9 29 23.4 23.0 137.9 72.0
N 8 8 8 8 8 8 8 8 8 8 8 8 8 8
5th 7.61 0.3165 0.629 0.0135 0.00675 0.015 0.2 0.4 2.9 10 ‐1.4 ‐2.7 1.3 0.7
Median 9.35 1.45 1.05 0.095 0.03 0.11 0.9 3.0 17.4 18 17.0 11.6 17.5 2.9
95th 9.73 4.125 3.63 0.5615 0.3915 0.8285 12.2 17.5 61.5 61 51.2 47.7 103.9 51.9
N 6 6 6 6 6 6 6 6 6 6 6 6 6 6
5th 8.325 1.3 0.3725 0.0325 0.00875 0.02375 0.3 1.0 7.1 6 2.2 0.4 1.5 1.0
Median 9.1 2.4 1.5 0.12 0.08 0.085 2.5 3.8 14.5 25 12.5 9.7 10.5 6.0
95th 9.375 5.875 2 0.3025 0.155 0.5075 4.8 9.5 20.5 33 19.4 19.1 70.0 16.1
N 2 2 2 2 2 2 2 2 2 2 2 2 2 2
Absolute value 7.8 17 6.4 0.23 0.16 0.22 5.0 7.2 11 106.7 6.0 3.8 2.2 1.5
Absolute value 8.6 6.4 1.7 0.13 0.04 0.28 1.3 4.1 16 28.3 14.8 11.9 12.8 3.9
SL‐DO‐NCLB008 9.5 0.057 0.034 1.1 1.8 1.71 0.6 ‐0.1 1.6 1.0
MD‐MC‐SL‐NCLB020 9.5 0.071 0.045 1.4 2.2 6.91 5.5 4.7 4.9 3.1
MD‐ST‐NCLB037 9.7 0.048 0.038 1.2 1.5 17 16 16 14.3 11
SL‐SX‐DO‐NCLB047 9.6 0.12 0.076 2.4 3.7 43 41 39 18.1 12
MD‐DO‐NCLB068 9.5 0.11 0.056 1.8 3.3 15 13 12 8.6 4.6
ST‐SL‐NCLB119 9.6 0.046 0.026 0.81 1.4 67 66 66 82.5 47
DO‐SD‐NCLB148 9.5 0.053 0.026 0.81 1.7 13 12 11 16.0 7.8
DO‐SL‐NCLB151 9.8 0.040 0.007 0.22 1.3 20 20 19 91.4 16
COAL1-NCLB068-TS 5.5 39 6.8 0.75 0.12 1.9 3.8 23 40 113 36 17 10.7 1.7
COAL 2-NCLB068-TS 5.1 39 0.74 1.4 0.83 1.6 26 44 5 12 ‐21 ‐38 0.21 0.12
COAL 3-NCLB068-TS 8.5 41 2.1 0.050 0.040 0.050 1.3 1.6 58 35 56 56 46.1 37
COAL 4-NCLB068-TS 6.3 44 0.96 0.48 0.20 0.84 6.3 15 19 16 12 3.5 3.0 1.2
COAL 5-NCLB068-MS NA 35 1.7 0.23 0.20 0.11 6.3 7.2 38 28 31 31 6.0 5.2
COAL 6-NCLB068-MS 7.6 31 1.1 0.20 0.15 0.15 4.7 6.3 20 18 15 14 4.3 3.2
COAL 7-NCLB068-BS 7.1 48 1.7 0.18 0.16 0.060 5.0 5.6 23 28 18 17 4.6 4.1
COAL ‐ NCLB047 8.2 1.5 0.14 4.4 47 32 28 ‐15 7.3 0.68
COAL ‐ NCLB068 8.4 0.88 0.53 17 28 33 16 5.5 2.0 1.2
Shale (SH)
Siltstone/Sandstone
(SL)
COMPOSITE COAL SAMPLES
kg CaCO3/t
INDIVIDUAL LITHOLOGICAL SECTIONS SAMPLES
Shale/Sandstone (SX)
COMPOSITE OVERBURDEN SAMPLES
INDIVIDUAL COAL SAMPLES
Carbonaceous
Mudstone
Carbonaceous Shale
(CS)
Dolerite (DO)
Grit/Mudstone
Gritstone (GS)
Sandstone/Siltstone
(SS)
Siltstone (ST)
Mudstone
Sandstone
SE
February 2019 18101804-324369-12
Figure C1: Mineralogical composition of Metsimaholo sample (Golder, 2013)
February 2019 18101804-324369-12
Table C2: Summary of NAG test results (1:100 solid to liquid ratio) for Metsimaholo overburden/interburden and coal samples (Golder, 2013)
Material type Overburden/interburden Composites Coal Composites Domestic WQ Parameter Units SL-DO SL-SX-DO ST-SL MD-MC-SL MD-ST MD-DO DO-SD Coal Coal
Borehole NCLB008 NCLB047 NCLB119 NCLB020 NCLB037 NCLB068 NCLB148 NCLB068 NCLB047 DWAF (1996)
NAG pH s.u 5.9 6.6 6.3 6.4 6.5 6.5 6.5 2.3 3.9 6 to 9
NAG SO4 kgH2SO4/t <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 110 96 ng
EC mS/m 40 46 33 38 39 42 39 127 36.3 70
TDS mg/l 266 307 218 255 264 280 262 851 243 450
NH3 mg(N)/l 2.5 1.4 <0.2 2.8 1.7 2.2 4.5 20 0.5 1.0
Alk (CaCO3) mg/l 60 48 20 8 16 56 60 <5 <5 ng
NO3 mg(N)/l 4.4 4.8 3.1 3.4 3.9 3.9 <0.2 <0.2 <0.2 6.0
Cl mg/l 9.0 9.0 6.0 <5 7.0 9.0 6.0 9.0 13 100
SO4 mg/l 42 107 23 38 46 34 17 439 51 200
F mg/l 0.4 0.2 <0.2 0.3 0.2 <0.2 <0.2 <0.2 0.2 0.70
Ag mg/l 0.035 0.065 <0.025 0.033 0.025 0.056 0.04 0.14 0.032 ng
Al mg/l 19 16 19 28 13 18 4.6 19 0.39 0.15
As mg/l 0.015 0.02 0.015 0.014 0.017 0.017 <0.010 <0.010 <0.010 0.010
B mg/l <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 0.125 ng
Ba mg/l 0.331 0.265 0.271 0.38 0.253 0.254 0.046 1.39 0.192 ng
Be mg/l <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 ng
Bi mg/l <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 ng
Ca mg/l 43 48 27 44 44 49 40 72 26 32
*Cd mg/l <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 0.005
Co mg/l 0.039 0.044 0.031 0.062 0.038 0.04 <0.025 <0.025 <0.025 ng
Cr mg/l <0.025 0.053 <0.025 0.036 <0.025 0.051 <0.025 0.24 <0.025 ng
Cu mg/l 0.176 0.108 0.09 0.207 0.123 0.162 0.083 0.11 0.031 1.0
Fe mg/l 34 30 26 45 22 28 6.5 35 3.8 0.10
February 2019 18101804-324369-12
Material type Overburden/interburden Composites Coal Composites Domestic WQ Parameter Units SL-DO SL-SX-DO ST-SL MD-MC-SL MD-ST MD-DO DO-SD Coal Coal
K mg/l 7.0 7.2 8.5 10 7.5 7.5 2.2 1.3 <1.0 < 50
Li mg/l 0.045 0.045 0.051 0.063 0.043 0.047 <0.025 0.052 <0.025 ng
Mg mg/l 11 12 10 16 9 12 7.0 12 4.0 30
Mn mg/l 1.3 1.2 0.61 1.4 0.84 1.0 0.37 0.25 0.085 0.050
Mo mg/l <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 ng
Na mg/l 14 25 25 27 28 18 11 16 13 100
Ni mg/l 0.087 0.11 0.056 0.13 0.073 0.097 0.11 0.07 0.03 ng
P mg/l <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 ng
Pb mg/l 0.034 0.041 0.05 0.064 0.049 0.035 <0.020 0.034 <0.020 0.01
S mg/l 7.8 12 7.5 9.3 8.5 11 7.9 16 15 ng
Sb mg/l <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ng
*Se mg/l <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 ng
Si mg/l 25 27 29 39 23 27 13 17 0.7 ng
Sn mg/l <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 <0.025 ng
Sr mg/l 0.42 0.41 0.49 0.60 0.48 0.45 0.14 1.5 0.271 ng
Ti mg/l 0.33 0.58 0.66 0.76 0.50 0.71 0.121 2.4 0.034 ng
V mg/l 0.047 0.084 0.038 0.076 0.049 0.097 0.042 0.30 <0.025 ng
W mg/l <0.025 0.037 0.036 0.038 0.03 0.031 <0.025 0.35 <0.025 ng
Zn mg/l <0.025 0.096 0.039 <0.025 <0.025 0.044 <0.025 <0.025 <0.025 3.0
Notes: ng = no guideline * Detection limit for Cd and Se are more than the guideline values ** Aesthetic guidelines ** *Operational guidelines
February 2019 18101804-324369-12
APPENDIX D
Kinetic results summary
Table D1: Summary of humidity cell data for overburden/interburden and coal samples from Vaalbank, Metsimaholo and New Vaal Colliery
Humidity Cell Composition
and Name
Parameters pH EC TDS (Meas)
TDS (Calc)
p- Alk m-Alk Cl NO3 SO4 Al As B Ba Ca Co Cr Cu Fe K Mg Mn Na Ni S Se Si Sr Ti V Zn
Units s.u (mS/cm)
(mg/l) (mg/l) mg/L CaCO3
mg/L CaCO3
mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l
Overburden/interburden
Sandstone-Mudstone (NVL 90015 COMP)
Week 0 5.8 220 1090 1786 0.3 4.6 10 0.75 1338 0.06 0.015 0.68 0.13 119 0.32 0.025 0.025 28.9 7.0 60 5.5 294 0.56 362 0.025 2.4 2.46 0.025 0.025 8.4
Initial Week 5.8 278 1390 1836 0.3 5.0 4.3 0.45 1421 0.025 0.015 0.45 0.15 131 0.09 0.025 0.025 0.57 7.0 59 2.8 379 0.17 432 0.025 1.6 2.89 0.025 0.025 4.7
Final Week 6.8 4 28 170 0.3 6.9 0.66 0.15 96 0.025 0.015 0.14 0.17 23 0.025 0.025 0.025 0.025 1.4 7.9 0.17 4.4 0.025 30 0.015 0.71 0.28 0.025 0.025 1.5
5th Percentile 5.4 7.3 38 125 0.3 3.3 0.53 0.15 85 0.025 0.015 0.09 0.118 21 0.025 0.025 0.025 0.025 1.5 7.0 0.16 4.2 0.025 28 0.015 0.61 0.28 0.025 0.025 0.76
Median 6.0 24 130 427 0.3 5.2 1.2 0.15 370 0.025 0.015 0.2 0.16 75 0.025 0.025 0.025 0.025 2.7 23 0.99 10 0.025 101 0.025 1.1 0.92 0.025 0.025 1.4
95th Percentile
6.8 218 1081 1904 0.3 7.4 6.3 1.22 1367 0.07 0.364 0.542 0.21 145 0.182 0.043 0.025 12 7.2 62 3.9 328 0.33 390 0.025 2.4 2.6 0.025 0.025 6.2
Sandstone/Siltstone-Mudstone
(NVL90017 COMP)
Week 0 4.3 317 1600 2905 0.3 2.0 31 2.49 2111 3.36 0.015 0.44 0.08 370 0.34 0.025 0.07 92 9.5 159 8.2 211 0.82 597 0.015 6.0 4.5 0.025 0.025 4.6
Initial Week 6.4 196 958 1479 0.3 4.6 8.4 1.06 1061 0.025 0.015 0.14 0.14 180 0.025 0.025 0.025 0.12 5.2 74 2.5 146 0.16 323 0.015 2.1 2.1 0.025 0.025 0.9
Final Week 6.9 48 247 448 0.3 30 1.6 0.15 297 0.025 0.015 0.14 0.19 96 0.025 0.025 0.025 0.025 2.3 22 0.47 4.8 0.025 98 0.015 1.9 0.71 0.025 0.025 0.33
5th Percentile 5.2 45 188 412 0.3 2.0 0.36 0.15 283 0.025 0.015 0.09 0.10 84 0.025 0.025 0.025 0.025 1.7 20 0.37 4.6 0.025 79 0.015 1.0 0.66 0.025 0.025 0.17
Median 6.2 80 403 652 0.3 4.3 1.3 0.15 492 0.025 0.015 0.14 0.17 125 0.025 0.025 0.025 0.06 2.8 37 1.5 16 0.055 153 0.015 1.6 1.2 0.025 0.025 0.37
95th Percentile
6.9 197 978 2050 0.3 14 16 2.7 1482 1.24 0.16 0.32 0.25 258 0.158 0.044 0.041 33 7.0 120 5.32 169 0.39 419 0.025 4.3 3.3 0.025 0.025 2.7
Mudstone-Siltstone (WRTM4)
Week 0 6.3 NA NA 218 0.3 52 2.9 4.2 103 0.191 0.005 0.361 0.207 37 0.002 0.001 0.003 0.052 9.8 10 0.013 3.4 0.016 0 0.142 1.5 0.402 0.017 0.0018 0.11
Initial Week 5.1 NA NA 199 0.3 2 1.6 1.5 344 0.04 0.0005 0.302 0.05 76 0.418 0.0005 0.002 1.6 7.1 26 0.79 24 1.03 0 0.072 1.7 1.22 0.001 <0.0001
5.6
Final Week 6.4 NA NA 120 0.3 41 0.85 1.1 72 0.025 NA NA NA 23 NA NA NA NA NA 7.9 0.025 5.0 NA 0 NA NA NA NA NA NA
5th Percentile 5.5 NA NA 60 0.3 21 0.27 1.1 51 0.0079 0.0005 0.1318 0.041 15 0.0007 0.0005 0.0014 0.005 2.6 6.7 0.003 3.3 0.0154
NA 0.0074 0.84 0.32 0.001 0.0002 0.058
Median 6.6 NA NA 199 0.3 27 0.58 2.0 74 0.04 0.002 0.302 0.073 28 0.002 0.0005 0.002 0.032 5.7 9.4 0.007 8.7 0.04 NA 0.026 1.5 0.56 0.002 0.0005 0.38
95th Percentile
7.5 NA NA 458 0.3 42 1.7 16 283 0.175 0.0042 0.4588 0.1734 72 0.25 0.001 0.003 1.1 9.2 26 0.49 42 0.64 NA 0.11 2.8 1.5 0.012 0.0015 3.6
Mudstone-Siltstone (WRTM5)
Week 0 7.7 NA NA 309 0.3 40 3.4 3.6 184 0.009 0.002 0.343 0.177 53 0.053 0.001 0.021 0.012 8.4 17 0.075 0.31 0.136 0 0.14 1.25 1.3 0.004 0.001 2.0
Initial Week 5.5 NA NA 293 0.3 4.4 1.5 1.4 349 0.039 0.0005 0.302 0.047 56 0.473 0.0005 0.001 0.99 8.4 21 1.1 59 1.16 0 0.08 1.67 0.86 0.001 <0.0001
5.5
Final Week 6.4 NA NA 125 0.3 43 0.63 0.7 46 0.025* NA NA NA 13.6* NA NA NA NA NA 5.4 0.025 9.9 NA 0 NA NA NA NA NA NA
5th Percentile 5.9 NA NA 51 0.3 27 0.26 0.78 31 0.0039 0.0005 0.0994 0.038 10 0.0007 0.0005 0.001 0.005 4.6 3.1 0.0014
1.9 0.0052
NA 0.0092 0.86 0.14 0.001 0.00027
0.039
Median 7.0 NA NA 293 0.3 40 0.53 1.78 66 0.031 0.002 0.30 0.083 30 0.004 0.0005 0.002 0.03 6.7 10 0.011 16 0.015 NA 0.026 1.4 0.70 0.002 0.0009 0.42
95th Percentile
8.0 NA NA 532 0.3 54 1.8 46 350 0.11 0.0026 0.51 0.16 55 0.305 0.001 0.0146 0.69 10 27 0.714 74 0.75 NA 0.12 2.7 1.6 0.0052 0.0013 4.1
Coal
Top & Middle Seam (NVL
90015 COAL)
Week 0 8.3 175 879 1285 0.3 131 32 11 736 0.19 0.015 3.9 0.21 26 0.025 0.025 0.025 0.025 3.8 5.9 0.025 353 0.025 202 0.31 1.4 0.82 0.025 0.025 0.11
Initial Week 8.6 118 590 738 4.32 91 4.1 9.5 437 0.51 0.015 3.2 0.27 11 0.025 0.025 0.025 0.05 2.4 3.2 0.025 232 0.025 137 0.015 1.7 0.44 0.025 0.025 0.025
Final Week 7.5 5.4 32 200 0.96 104 0.80 0.15 22 1.66 0.015 0.83 0.43 3.4 0.025 0.025 0.025 0.61 2.4 1.5 0.025 68 0.025 10 0.015 18 0.13 0.06 0.025 0.19
5th Percentile 7.5 7.6 33 115 0.3 64 0.67 0.15 15 0.132 0.015 0.49 0.16 1.5 0.025 0.025 0.025 0.041 1.3 0.57 0.023 36 0.025 7.1 0.015 1.6 0.041 0.025 0.025 0.025
Median 8.5 18 87 197 4.0 96 1.3 0.15 42 1.6 0.015 1.7 0.305 3.3 0.025 0.025 0.025 0.54 2.4 1.2 0.025 70 0.025 20 0.015 6.3 0.1 0.065 0.025 0.15
95th Percentile
9.3 117 582 930 12 130 14 23 542 4.1 0.015 3.9 0.472 16 0.025 0.025 0.025 1.1 3.1 4.1 0.025 274 0.027 160 0.20 16 0.57 0.22 0.025 0.45
Middle Seam (NVL90021
COAL)
Week 0 8.3 80 402 571 0.3 211 16 0.35 209 8.9 0.015 4.6 0.33 10 0.025 0.025 0.025 0.5 2.4 2.4 0.025 182 0.025 49 0.15 11 0.18 0.39 0.025 0.05
Initial Week 9.0 35 175 291 7.16 102 6.3 0.22 121 0.025 0.015 3.9 0.37 4.9 0.025 0.025 0.05 0.8 1.7 1.4 0.16 119 0.025 45 0.025 15 0.09 0.48 0.025 0.33
Final Week 7.8 14 70 107 2.44 59 1.1 0.15 21 4.19 0.015 0.6 0.13 1.1 0.025 0.025 0.025 0.32 1.2 0.42 0.025 34 0.025 5.03 0.025 5.3 0.025 0.38 0.025 0.025
5th Percentile 7.6 6.2 34 106 0.3 63 0.58 0.14 14 0.59 0.015 0.58 0.13 1.3 0.025 0.025 0.025 0.14 0.99 0.41 0.025 34 0.025 4.7 0.015 4.5 0.025 0.070 0.023 0.025
Median 8.5 17 88 173 4.7 98 1.1 0.15 37 4.1 0.015 1.3 0.17 2.0 0.025 0.025 0.025 0.36 1.5 0.57 0.025 56 0.025 11 0.02 8.6 0.035 0.23 0.025 0.05
95th
Percentile 9.1 38 190 415 13 167 10 0.37 337 8.1 0.048 4.1 0.36 6.8 0.025 0.025 0.034 0.71 2.2 1.7 0.072 141 0.025 47 0.069 17 0.12 0.42 0.025 0.239
Top & Middle Seam (NCLB 068 COAL)
Week 0 8.2 234 1160 1806 0.3 131 41 1.03 1145 0.025 0.015 1.9 0.19 75 0.025 0.025 0.025 0.025 4.0 11 0.17 451 0.07 315 0.015 0.83 1.58 0.025 0.025 0.1
Initial Week 8.2 231 1140 1455 0.3 74 16 0.15 922 0.025 0.015 1.61 0.17 60 0.025 0.025 0.025 0.025 3.0 13 0.025 396 0.025 307 0.015 0.57 1.75 0.025 0.025 0.46
Humidity Cell Composition
and Name
Parameters pH EC TDS (Meas)
TDS (Calc)
p- Alk m-Alk Cl NO3 SO4 Al As B Ba Ca Co Cr Cu Fe K Mg Mn Na Ni S Se Si Sr Ti V Zn
Units s.u (mS/cm)
(mg/l) (mg/l) mg/L CaCO3
mg/L CaCO3
mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l
Final Week 7.5 26 134 264 0.3 44 0.64 0.15 158 0.025 0.015 0.45 0.18 31 0.025 0.025 0.025 0.025 1.5 12 0.025 33 0.025 50.3 0.015 0.36 0.72 0.025 0.025 0.16
5th Percentile 7.2 12 64 189 0.3 30 0.62 0.15 113 0.025 0.015 0.3 0.15 14 0.025 0.025 0.025 0.025 1.3 3.7 0.025 26 0.020 37 0.015 0.24 0.35 0.025 0.025 0.025
Median 7.6 31 159 348 0.3 45 1.3 0.15 210 0.025 0.015 0.82 0.19 21 0.025 0.025 0.025 0.025 1.6 7.3 0.025 79.1 0.025 71 0.015 0.44 0.54 0.025 0.025 0.20
95th
Percentile 8.4 225 1108 1578 0.3 94 25 0.46 1000 0.15 0.14 1.7 0.24 65 0.025 0.025 0.025 0.041 3.4 12 0.079 415 0.041 338 0.025 0.74 1.64 0.025 0.025 0.49
Middle and Bottom Seam (NCLB 047
COAL)
Week 0 8.2 47 234 387 0.3 151 2.2 0.49 144 6.2 0.015 3.6 0.39 9 0.025 0.025 0.025 0.48 1.4 1.7 0.025 120 0.025 215 0.025 9.0 0.17 0.26 0.025 0.12
Initial Week 9.0 15 79 199 2.5 53 1.4 0.21 88 3.1 0.015 2.2 0.24 4.0 0.025 0.025 0.025 0.22 1.0 0.54 0.025 61 0.01 30 0.025 5.1 0.06 0.13 0.025 0.025
Final Week 7.4 11 54 79 1.9 33 0.56 0.15 27 1.14 0.015 0.35 0.1 1.0 0.025 0.025 0.025 0.12 0.84 0.17 0.025 26 0.025 8.0 0.025 1.6 0.025 0.025 0.025 0.025
5th Percentile 7.6 9 44 77 0.3 35 0.52 0.15 22 0.30 0.015 0.43 0.093 0.85 0.025 0.025 0.025 0.048 0.80 0.15 0.025 25 0.020 7.1 0.015 1.0 0.020 0.025 0.025 0.025
Median 8.5 15 67 117 1.5 52 1.0 0.15 39 1.3 0.015 0.78 0.18 1.4 0.025 0.025 0.025 0.17 1.2 0.33 0.025 37 0.025 13 0.015 1.8 0.025 0.025 0.025 0.025
95th
Percentile 9.0 39 195 369 5.8 104 2.2 0.47 163 4.5 0.015 2.7 0.29 18 0.025 0.025 0.025 0.40 1.9 5.1 0.16 82 0.025 117 0.025 7.2 0.23 0.182 0.025 0.169
Top, Middle & Bottom Seam (NVL 90057
COAL)
Week 0 8.4 138 690 1014 0.3 202 3.5 0.15 575 0.2 0.015 1.9 0.19 13 0.025 0.025 0.025 0.025 3.6 2.8 0.025 291 0.025 196 0.11 1.5 0.52 0.025 0.025 0.025
Initial Week 8.6 133 663 919 0.3 127 2.0 0.15 546 0.38 0.015 1.75 0.21 8.3 0.025 0.025 0.025 0.025 2.7 2.2 0.025 279 0.025 192 0.025 1.2 0.44 0.025 0.025 0.025
Final Week 8.0 19 96 235 0.3 83 1.9 0.87 85 2.78 0.015 0.92 0.2 3.3 0.025 0.025 0.025 0.19 2.5 1.2 0.06 72 0.025 27.8 0.015 7.6 0.21 0.025 0.025 0.025
5th Percentile 7.7 12 62 114 0.3 79 0.51 0.15 38 0.31 0.015 0.57 0.16 2.0 0.025 0.025 0.025 0.025 1.3 0.49 0.025 64 0.025 12 0.015 1.4 0.076 0.025 0.025 0.025
Median 8.5 20 99 247 4.6 119 1.2 0.15 69 2.8 0.015 0.96 0.21 3.3 0.025 0.025 0.025 0.18 2.0 0.79 0.025 86 0.025 26 0.015 4.2 0.13 0.09 0.025 0.025
95th
Percentile 8.8 130 648 952 6.9 211 3.8 0.85 558 6.7 0.015 1.8 0.32 10 0.025 0.025 0.025 0.43 3.2 2.4 0.039 284 0.025 194 0.063 12 0.472 0.292 0.025 0.064
Over-burden
5th Percentile 5.4 7.4 42 102 0.30 2.9 0.27 0.15 38 0.011 0.0005 0.082 0.044 13 0.001 0.0005 0.0012 0.005 1.5 5.2 0.002 3.5 0.008 29 0.0086 0.66 0.28 0.001 0.0003 0.084
Median 6.4 66 325 363 0.30 25 0.69 1.2 114 0.03 0.02 0.21 0.14 56 0.03 0.03 0.03 0.03 4.2 22 0.40 14 0.04 146 0.02 1.4 0.89 0.03 0.03 0.61
95th
Percentile 7.8 217 1073 1818 0.30 48 5.5 14 1114 0.15 0.164 0.49 0.22 176 0.336 0.025 0.025 1.6 9.4 72 3.6 220 0.77 411 0.093 3.4 2.6 0.025 0.025 5.3
New Vaal Colliery Coal
5th Percentile 7.5 7.9 36 108 0.30 66 0.51 0.15 15 0.19 0.015 0.54 0.13 1.4 0.025 0.025 0.025 0.025 1.1 0.42 0.025 34 0.025 5.05 0.015 1.5 0.025 0.025 0.025 0.025
Median 8.5 18 89 192 4.20 103 1.2 0.15 60 2.8 0.02 1.1 0.21 2.4 0.03 0.03 0.03 0.32 2.0 0.73 0.03 72 0.03 20 0.02 6.0 0.08 0.11 0.03 0.05
95th
Percentile 9.1 110 548 680 12 202 6.3 9.5 575 7.7 0.015 3.9 0.43 11 0.025 0.025 0.025 0.82 3.0 2.8 0.025 279 0.025 192 0.123 18 0.44 0.38 0.025 0.33
Metsimaholo Coal
5th Percentile 7.4 9.0 45 82 0.30 30 0.57 0.15 24 0.025 0.015 0.32 0.10 1.0 0.025 0.025 0.025 0.025 0.90 0.18 0.025 25 0.015 7.5 0.015 0.27 0.025 0.025 0.025 0.025
Median 8.1 17 83 215 0.30 49 1.1 0.15 130 0.15 0.02 0.78 0.19 14 0.03 0.03 0.03 0.04 1.6 3.6 0.03 50 0.03 44 0.02 0.89 0.35 0.03 0.03 0.08
95th
Percentile 9.0 97 487 1181 4.7 112 12 0.48 743 3.4 0.015 2.2 0.24 51 0.025 0.025 0.025 0.35 2.7 12 0.12 324 0.025 312 0.025 5.9 1.3 0.14 0.025 0.44
Figure D2: Time series graphs for overburden/interburden samples (Vaalbank and New Vaal Colliery) showing change in conductivity, sulphate and pH over 21 week humidity cell test (Golder, 2013)
APPENDIX E
Metsimaholo roof and floor NAG leach results
Table E1 NAG leach results for Metsimaholo roof material
Parameter NCLB037‐7 NCLB037‐8 NCLB151‐07 NCLB068‐11 NCLB148‐02 NCLB008‐6 NCLB 020‐6 NCLB020‐10 NCLB047‐09 NCLB119‐01 NCLB119‐06 NCLB119‐13
all units in mg/L Class 0 Class 1
pH 3.9 3.4 3.1 3.5 4.5 3.3 3.4 2.2 2.4 4.1 5.1 3.1 6-9 4.5-10
EC 28 53 44 54 27 46 26 270 146 26 37 59 70 150
TDS 281 452 150 252 63 184 74 427 555 100 114 256 450 1000
Ammonia as N 7.7 1.7 0.5 1 <0.2 2.2 <0.2 <0.2 3 <0.2 <0.2 0.8 1 2
Alkalinity as CaCO3 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 40 <5 ng ng
Nitrate as N <0.2 <0.2 <0.2 6.9 2.1 3.2 7.9 15 <0.2 6.6 <0.2 1.8 6 10
Chloride as Cl 9 20 <5 5 <5 10 <5 <5 <5 <5 12 <5 100 200
Sulphate as SO4 136 131 76 131 7 65 <5 264 421 13 15 154 200 400
Fluoride as F 0.5 0.3 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 0.7 1
Ag <0.010 <0.010 <0.010 0.039 <0.010 0.015 <0.010 0.012 <0.010 <0.010 <0.025 <0.010
Al 6.37 18 1.72 10 0.388 5.63 0.647 6.38 7.9 0.678 0.218 2.04 0.15 0.5
As 0.036 0.078 0.013 0.042 <0.010 0.013 <0.010 0.012 0.023 <0.010 <0.010 <0.010 0.01 0.05
B 0.358 0.904 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 <0.010 ng ng
Ba 0.97 2.73 0.272 0.034 0.032 0.282 0.052 0.044 0.044 0.055 <0.025 0.062 ng ng
Be <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 <0.010 ng ng
Bi <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 <0.010 ng ng
Ca 13 12 22 8 24 22 7 3 21 14 39 47 32 80
Cd <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.005 <0.010 0.003 0.005
Co 0.136 0.057 0.029 0.073 <0.010 0.275 <0.010 0.469 0.168 <0.010 <0.025 0.061 ng ng
Cr 0.02 0.02 <0.010 0.016 <0.010 0.064 <0.010 0.104 0.031 <0.010 <0.025 0.031 ng ng
Cu 0.106 0.068 0.136 0.06 0.003 0.123 <0.010 0.64 0.097 <0.010 <0.025 0.068 1 1.3
Fe 13 24 1.81 15 0.246 21 0.42 52 49 0.208 <0.025 9.18 0.5 1
K 5.1 9.5 1.5 6.5 1.5 2.6 0.837 0.389 1.9 1.5 1 0.824 25 50
Li 0.025 0.024 0.013 0.022 <0.010 0.007 0.012 0.018 0.043 <0.010 <0.025 0.014 ng ng
Mg 8 5 2 6 1 12 2 4 19 4 2 19 70 100
Mn 0.288 0.13 0.224 0.154 0.278 0.866 0.375 0.287 2.27 0.389 0.61 2.45 0.1 0.4
Mo 0.015 0.013 <0.010 0.011 <0.010 0.01 <0.010 <0.010 0.011 <0.010 <0.025 <0.010 ng ng
Na 63 96 23 68 8 25 12 6 29 19 13 12 100 200
Ni 0.173 0.089 0.357 0.112 <0.010 0.23 <0.010 1.38 0.324 <0.010 <0.025 0.105 ng ng
P <0.800 <0.800 <0.800 <0.800 <0.800 <0.800 <0.800 <0.800 <0.800 5.43 <0.025 <0.800 ng ng
Pb <0.010 0.025 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.020 <0.010 0.01 0.05
S 40 36 21 37 <0.100 17 <0.100 148 149 0.3 3.015 51 ng ng
Sb <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ng ng
Se <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.020 <0.010 0.02 0.05
Si 17 73 7.8 50 4.6 13.1 4.3 4.1 14.3 5.2 1.5 2.8 ng ng
Sn <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 <0.010 ng ng
Sr 0.302 0.308 0.237 0.362 0.17 0.35 0.102 0.148 0.333 0.224 0.203 0.202 ng ng
Ti 0.203 0.693 0.08 0.325 0.036 1.24 0.017 0.017 0.679 0.046 <0.025 0.254 ng ng
V 0.119 0.105 0.066 0.072 <0.010 0.249 <0.010 0.338 0.087 0.01 <0.025 0.061 0.1 1
W <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 <0.010 ng ng
Zn 1.08 1.5 0.187 0.242 0.075 0.711 0.072 0.462 0.398 0.089 0.042 0.412 3 5
DWAF (1996)
Peroxide leach (1:100)
Table E2: NAG leach results for Metsimaholo floor material
Parameter NCLB037 ‐ 7 NCLB037 ‐ 9 NCLB068‐12 NCLB148 ‐ 2 NCLB148 ‐ 6 NCLB008 ‐ 6 NCLB020‐07 NCLB020‐10 NCLB047‐10 NCLB119‐06
all units in mg/L Class 0 Class 1
pH 3.9 2.7 2.7 4.5 2.7 3.3 3.2 2.2 3.5 3.1 6-9 4.5-10
EC 28 53 42 27 50 46 42 270 73.6 59 70 150
TDS 281 61 72 63 81 184 124 427 405 256 450 1000
Ammonia as N 7.7 1.1 0.6 <0.2 <0.2 2.2 1 <0.2 2.8 0.8 1 2
Alkalinity as CaCO3 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 ng ng
Nitrate as N <0.2 <0.2 0.3 2.1 4.5 3.2 <0.2 15 14 1.8 6 10
Chloride as Cl 9 <5 <5 <5 <5 10 <5 <5 <5 <5 100 200
Sulphate as SO4 136 25 23 7 39 65 66 264 246 154 200 400
Fluoride as F 0.5 0.3 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 0.7 1
Ag <0.010 <0.010 <0.010 <0.010 <0.010 0.015 <0.010 0.012 <0.010 <0.025
Al 6.37 1.12 2.12 0.388 0.929 5.63 1.61 6.38 4.49 0.218 0.15 0.5
As 0.036 0.014 0.054 <0.010 <0.010 0.013 <0.010 0.012 <0.010 <0.010 0.01 0.05
B 0.358 <0.010 0.021 <0.010 <0.010 <0.010 <0.010 <0.010 0.045 <0.025 ng ng
Ba 0.97 0.044 0.138 0.032 0.122 0.282 0.089 0.044 0.144 <0.025 ng ng
Be <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 ng ng
Bi <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 ng ng
Ca 13 18 10 24 3 22 13 3 20 39 32 80
Cd <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.005 0.003 0.005
Co 0.136 0.104 0.17 <0.010 0.04 0.275 0.13 0.469 0.112 <0.025 ng ng
Cr 0.02 0.032 0.079 <0.010 <0.010 0.064 0.012 0.104 0.036 <0.025 ng ng
Cu 0.106 0.416 0.514 0.003 0.136 0.123 0.071 0.64 0.043 <0.025 1 1.3
Fe 13 2.28 3.47 0.246 3.69 21 5.51 52 72 <0.025 0.5 1
K 5.1 1.3 0.958 1.5 0.811 2.6 1.8 0.389 2.1 1 25 50
Li 0.025 <0.010 <0.010 <0.010 <0.010 0.007 <0.010 0.018 0.036 <0.025 ng ng
Mg 8 1 1 1 2 12 10 4 15 2 70 100
Mn 0.288 0.056 0.133 0.278 0.108 0.866 0.483 0.287 5.54 0.61 0.1 0.4
Mo 0.015 0.011 0.032 <0.010 <0.010 0.01 <0.010 <0.010 <0.010 <0.025 ng ng
Na 63 10 14 8 11 25 16 6 53 13 100 200
Ni 0.173 0.491 0.516 <0.010 0.096 0.23 0.13 1.38 0.322 <0.025 ng ng
P <0.800 <0.800 1.05 <0.800 <0.800 <0.800 <0.800 <0.800 <0.800 <0.025 ng ng
Pb <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.020 0.01 0.05
S 40 7 6.1 <0.100 10 17 16 148 70 3.015 ng ng
Sb <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ng ng
Se <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.020 0.02 0.05
Si 17 2.8 5.7 4.6 4 13.1 3.4 4.1 17.7 1.5 ng ng
Sn <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 ng ng
Sr 0.302 0.084 0.172 0.17 0.164 0.35 0.147 0.148 0.489 0.203 ng ng
Ti 0.203 0.243 1.55 0.036 0.17 1.24 0.087 0.017 0.381 <0.025 ng ng
V 0.119 0.41 1.07 <0.010 0.085 0.249 0.052 0.338 0.117 <0.025 0.1 1
W <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.025 ng ng
Zn 1.08 1 1 0.075 0.608 0.711 0.689 0.462 0.48 0.042 3 5
DWAF (1996)
Peroxide leach (1:100)
APPENDIX F
Document Limitations
February 2019 FORM NAME18101804-324369-12
62/77
This document has been provided by Golder Associates Africa Pty Ltd (“Golder”) subject to the following
limitations:
i) This Document has been prepared for the particular purpose outlined in Golder’s proposal and no responsibility is accepted for the use of this Document, in whole or in part, in other contexts or for any other purpose.
ii) The scope and the period of Golder’s Services are as described in Golder’s proposal, and are subject to restrictions and limitations. Golder did not perform a complete assessment of all possible conditions or circumstances that may exist at the site referenced in the Document. If a service is not expressly indicated, do not assume it has been provided. If a matter is not addressed, do not assume that any determination has been made by Golder in regard to it.
iii) Conditions may exist which were undetectable given the limited nature of the enquiry Golder was retained to undertake with respect to the site. Variations in conditions may occur between investigatory locations, and there may be special conditions pertaining to the site which have not been revealed by the investigation and which have not therefore been taken into account in the Document. Accordingly, additional studies and actions may be required.
iv) In addition, it is recognised that the passage of time affects the information and assessment provided in this Document. Golder’s opinions are based upon information that existed at the time of the production of the Document. It is understood that the Services provided allowed Golder to form no more than an opinion of the actual conditions of the site at the time the site was visited and cannot be used to assess the effect of any subsequent changes in the quality of the site, or its surroundings, or any laws or regulations.
v) Any assessments made in this Document are based on the conditions indicated from published sources and the investigation described. No warranty is included, either express or implied, that the actual conditions will conform exactly to the assessments contained in this Document.
vi) Where data supplied by the client or other external sources, including previous site investigation data, have been used, it has been assumed that the information is correct unless otherwise stated. No responsibility is accepted by Golder for incomplete or inaccurate data supplied by others.
vii) The Client acknowledges that Golder may have retained sub-consultants affiliated with Golder to provide Services for the benefit of Golder. Golder will be fully responsible to the Client for the Services and work done by all its sub-consultants and subcontractors. The Client agrees that it will only assert claims against and seek to recover losses, damages or other liabilities from Golder and not Golder’s affiliated companies. To the maximum extent allowed by law, the Client acknowledges and agrees it will not have any legal recourse, and waives any expense, loss, claim, demand, or cause of action, against Golder’s affiliated companies, and their employees, officers and directors.
viii) This Document is provided for sole use by the Client and is confidential to it and its professional advisers. No responsibility whatsoever for the contents of this Document will be accepted to any person other than the Client. Any use which a third party makes of this Document, or any reliance on or decisions to be made based on it, is the responsibility of such third parties. Golder accepts no responsibility for damages, if any, suffered by any third party because of decisions made or actions based on this Document.
GOLDER ASSOCIATES AFRICA (PTY) LTD
APPENDIX G
Specialist Declaration and CV
SPECIALIST DECLARATION As required under Appendix 6 of the Environmental Impact Assessment Regulations, 2014 (as amended), I,
Dr Koovila Naicker, declare that:
I act as an independent specialist in this application;
I will perform the work relating to the application in an objective manner, even if this results in views and
findings that are not favourable to the applicant;
I declare that there are no circumstances that may compromise my objectivity in performing such work;
I have expertise in conducting the specialist report relevant to this application, including knowledge of
Acts, Regulations and any guidelines that have relevance to the proposed activity;
I will comply with all applicable Acts and Regulations in compiling this report;
I have not, and will not engage in, conflicting interests in the undertaking of the activity;
I undertake to disclose to the applicant and the competent authority all material information in my
possession that reasonably has or may have the potential of influencing:
any decision to be taken with respect to the application by the competent authority; and
the objectivity of any report, plan or document to be prepared by myself for submission to the
competent authority;
All the particulars furnished by me in this declaration are true and correct.
Signature of the specialist:
Golder Associates Africa (Pty) Ltd
Name of company (if applicable):
28 February 2019
Date:
1
Curriculum Vitae KOOVILA NAICKER
Education
B. Ed (Sc) Physics, Chemistry, Education, University of Durban Westville, KZN, South Africa, 1993
B.Sc. (Cum Laude) Chemistry , University of Durban Westville, KZN, South Africa, 1997
PhD (MSc converted to PhD) Environmental Analytical Chemistry, University of Witwatersrand, JHB, South Africa, 2005
Management Development Programme - MDP Strategy implementation, Operations management, Marketing and information management, Financial and management accounting, Economics for business, UNISA -School of Business Leadership, JHB. South Africa, 2009
Certifications
Professional Natural Scientist by South African Council for Natural Scientific Professions - 400124/08, 23 July 2008
Languages
Afrikaans – Fluent
English – Fluent
Golder Associates Africa (Pty.) Ltd. – Johannesburg
Associate Koovila is an Associate and senior geochemist at Golder Associates Africa, Mining Region (Water Division). Prior to her career at Golder (past 14 years) she consulted) and lectured for ~3 years in the Environmental Chemistry department (University of Witwatersrand). She is currently involved in managing integrated projects that provide technical support and solutions in: Groundwater and Geochemistry risk assessments; Environmental Social Impact Assessments, Engineering design of mine residue facilities, Integrated water and waste licence management licences/plans and Health safety environment social management systems. Koovila’ s project experience ranges in South African power (ash and UCG) and mining including diamond, manganese, coal, gold, platinum mining; East Africa Europe (Turkey) coal/gold mining; and in Africa banded iron formations, copper-belt, nickel and gold mining. Her areas of specialisation includes: Source-Pathway-Receptor assessment, acid and metalliferous drainage (AMD) related projects including field and laboratory geochemical testing programs, AMD modelling and management plans, pyrite oxidation modelling, geochemical modelling, mine waste classification, (un)saturated flow modelling and AMD treatment and abatement.
Employment History
University of Witwatersrand – Johannesburg, South Africa Lecturer – Analytical/Environmental Chemistry (2002 to 2005)
Junior lecture for school of chemistry – analytical environmental chemistry group. Lectured to first year engineers, chemistry undergraduates and environmental chemistry post graduates students. Postgraduate lectures included workshops on chemometric and geochemical modelling. Other outputs include three publications in international journals and several local and international posters and papers.
Hartebeesthoek Radio Astronomy Observatory (HARTRAO) – Johannesburg,
South Africa Educational Officer (1998 to 2000)
Responsible for the scientific communication of astronomy program at HARTRAO and astronomy in general to visiting groups. Presented and developed astronomy workshops throughout S.A to teachers and at national science fairs.
2
Curriculum Vitae KOOVILA NAICKER
PROJECT EXPERIENCE – MINING
Eurasian Resources Group (ERG) - Africa
Katanga, DRC
Geochemical characterisation for Metalkol, Boss, Comide, Frontier Mines. The specialist studies for each mine site entailed collection of samples (~500 samples in total) from existing mine components and diamond drilled core to assess compliance with DRC Mine Regulations (2003) effluent discharge water. The geochemical results were also integrated into the detailed engineering design and impact assessment studies (groundwater contaminant transport model & impact assessment).
Ivanhoe Mines S.A Katanga, DRC
Specialist geochemist for the Kamoa and Kakula Mines (2010 to present). Geochemical characterisation (static and kinetic test work) for ore, waste rock and tailings materials. Risk classification according to DRC Mining Regulations and mine drainage modelling completed for the Kamoa and Kakula deposits. Current work in 2019 includes revision of source-term models and re-evaluation of potential groundwater impacts for Kakula underground mine.
ERG - Boss Mining Route Likasi 238
Lubumbashi
Source-Pathway-Receptor project for Mukondo Area that involved sampling, test work and spatial delineation for historic tailings at the Mukondo source area and pathway (stream & sediments). Human health risk complete for the SPR investigation to assess remedial options for marginal tailings deposited historically.
Field kinetic cells (barrels) set up for Kabolela Mine to assess site specific metal leaching rates and quality, and time for neutralisation depletion and acid onset. The field kinetic results are intended to guide the long term WRD management options and cover design.
Hattat Enerji ve Maden Tic. A.Ş. (HEMA)
Bartın, Turkey
Geochemistry ARD/ML assessment completed from static and kinetic results from geological core samples collected by Golder and onsite geologist. The assay total sulphur and sulphide sulphur was used to guide the sampling strategy and number of samples. Laboratory simulation of the coal discard was set up using High Density Liquid Separation. The laboratory results was used to develop contaminant source-term as input into the solute transport model for impact assessment from the proposed underground mine.
SEK Katanga , DRC
Geochemistry ARD/ML assessment for new pits. Technical inputs included sampling protocol, geochemical characterisation, mine drainage(source-term) modelling for input into contaminant transport model and site-specific conceptual water mitigation options.
Balama Graphite Project
Pemba, Mozambique
Technical specialist inputs to the feasibility study for Nicanda Hill Prospect involving assessment of compliance of in country environmental laws and modelling of impact of mine component to the receiving groundwater and surface water environment.
Maamba Coal Mine Livingstone, Zambia
Technical input into the development of an integrated health and safety, environmental and social management plan/system (HSESMP) inclusive of closure planning, groundwater and geochemistry assessment, health impact assessment, RAP monitoring and greenhouse gas evaluation. Involved prediction of mine drainage quality (from kinetic tests) as inputs into the numerical groundwater model
3
Curriculum Vitae KOOVILA NAICKER
Kipushi Corporation SPRL
Lubumbashi, Democratic Republic of Congo
Geochemistry lead for the baseline study for historic copper underground mine working and TSF(s). The baseline involved sampling and data analysis for underground mine water pumped out and historic concentrate, tailings and soil samples. Geochemistry feasibility assessment involved sampling and characterisation of core samples and prediction of TSF and underground mine water quality for the Big Zinc Project.
Platreef PGM Project Limpopo, South Africa
Geochemistry study to support the ESIA, engineering design for tailings and waste rock facilities and Water Use Licence Application for the new mine. Technical motivation (Groundwater risk assessment) to Department of Water and Sanitation to relax liner conditions for proposed Reitfontein TSF,
Mafube LifeX Project Middelburg,
Mpumalanga, South Africa
Geochemical characterisation and prediction of pit water qualities for the life of mine as input into the ESIA. The static and kinetic results identified stratigraphic units and coal seams that have acid generating potential and metal leaching potential. The geochemical model was validated using monitoring data available for the current operations. The closure model results were intergrated with the closure mine planning.
DeBeers Kimberley Mines
Northern Cape, South Africa
Waste classification and groundwater impact assessment for new Stadium Paste Facility. The work involved providing technical support for the client to Department of Water Affairs for the Water Use Licence conditions
New Vaal LifeX - Anglo American Thermal
Coal Sasolburg/Vereeniging,
South Africa
Geochemical specialist study for LifeX project. The work involved review data analysis and source-term development for the opencast and underground sections for integration into regional groundwater model and identification of potential impact to water resources during operational and post-closure phases.
Seriti Resources Metsimaholo Colliery
Sasolburg, South Africa
Geochemistry scoping study to assess potential of the various mining disturbed to generate acid and metalliferous drainage (AMD) as part of the Metsimaholo (previously Coalbrook) mining rights retention.
Tulu Kapi Mine - Nyota Minerals
Addis Abba, Ethiopia
Geochemistry assessment of ARD/ML risk from the proposed mining operations and recommendations of conceptual mitigation measures to impacts to local surface water and groundwater environment. Geoenvironmental models were used in addition to geochemical testwork on core samples. Kinetic test underway to confirm long-term impacts and refine proposed mitigations.
Tarkwa Mine - Goldfield
Ghana, Ghana
Assessment proposed TSF 4 impact to surface and groundwater resources. The study included data interpretation, conceptualisation and semi-quantitative seepage assessment ( by use of geo-environmental models and available data) for the proposed co-disposal tailings facility.
Lumwnana Mine - Barrick Corporation
Solwezi, Zambia
Geochemical characterisation study for integration with mine planning, engineers water and waste management for the proposed expansion project. The work involved sampling programme, static and kinetic testwork and assessment of ARD/ML risk for the Chimiwungo deposit.
4
Curriculum Vitae KOOVILA NAICKER
PROJECT EXPERIENCE – WASTE
Eskom Power Station Johannesburg, South
Africa
Fly Ash and Bottom Ash was collected from 15 Power Stations for classification/assessment in acordance to South African NEMWA Regulations. The ash samples were test for metal leaching (Autralian and USEPA leach procedure) and, radionuclide /isotop isganture for the baseline assessment
Delta EMD Nelspruit, South Africa
Initial assessment of remediation of options for the manganese groundwater pollution plume. The initial assessment involved geochemical modelling using different chemical additives under oxidising conditions and predicting the dominant manganese species and saturation indices for credible minerals.
Manganese Metal Company - Pappas
Quarry Nelspruit, MP, South
Africa
Development of a dynamic water and salt balance for the Pappas Quarry waste residue facility to understand the post-closure water management requirements and strategies for the site. Submitted to DWA as part of the post closure application process. Quantification of the post-closure water managment liability was done using the water and salt balance model.
PROJECT EXPERIENCE – HYDROGEOLOGY
South 32 Integrated Wolvekrans Geochem,
Salt Balance & Groundwater Model Johannesburg, South
Africa
Technical guidance and project management for Wolvekrans Colliery for developing mine wide groundwater, geochem and salt balance understanding to guide mitigation and water management liabilities. FeFlow and Goldsim models were used to set up the site wide model to meet the water use licence conditions.
Arnot Colliery Mooifontein Reserve -
Exxaro Coal Mpumalanga, South
Africa
Hydrological and geochemical evaluation for 3 pans in the reserve area south-east of the backfilled Arnot Pit. The chemical signature for the pans indicated that selected pan inflows could from the shallow weathered aquifer and that water loss to the groundwater was occurring, limiting evaporation process and salinity of the pan water.
Zonnebloom Greenfields
Witbank, MP, South Africa
First-order ARD risk assessment of coal and overburden material to assess the consequences of storing and placement of waste and risks associated with selected activities from the proposed coal mining project. Subsequent work involves predicting the resultant drainage from pit backfilling and the contaminant transport associated with spoils backfilling,
PROJECT EXPERIENCE – ENVIRONMENTAL ASSESSMENT
Moyoko Iron Ore Project
Mbinda, north-east of Pointe Noire, Republic of
Congo
Geochemical characterisation of Banded Iron Formation for the proposed project. Phase 1 work entailed sampling and static testwork and qualitaive assessment of risks. Tailings characterisation and classification was conducted to integrate with the engineering design and mine planning.
Dalyshope Waterberg Mine
Ellisras - Limpopo, South Africa
First-order (concept level) ARD risk assessment for the Ellisras /Waterberg Coalfield. The study involved sampling and static geochemical characterisation for overburden, partings and coal plies stratigraphic units that comprising Beaufort Group and overlying Ecca Group, to identify the geological units that will be potentially acid generating during mining.
5
Curriculum Vitae KOOVILA NAICKER
Zincor 7L3-4 Rehab & Closure
Springs, South Africa
Source characterization of 7L3 and 7L4 TSFs. Conceptualisation, sampling conducted to inform the geochemical and flow models. A range of seepage qualities over a 50 year period were simulated. Unsaturated flow model was based on material properties and climate. Mass load transfer to groundwater was integrated with numerical groundwater model. Calibration for mass transfer was done using in situ piezometer monitoring data.
Kabanga Nickel Mine Kagera District,
Tanzania
Sampling and baseline data collection (12 months) and laboratory analysis for SEIA which involved collecting of surface water sediments, and groundwater samples.
New Denmark Colliery Standerton, South Africa
Preliminary assessment of the ARD from the North and Southern waste rock dumps by conducting static tests of waste rock composites.
Moatize Coal Project Feasibility Study
Tete, Mozambique
Involved in developing the source term model for the groundwater modelling. This required manipulation of geochemical static and kinetic test to determine if the pit will go acidic over time and to calculate the recharge volume and qualities from the waste and slurry to the groundwater.
Tenke Fungurume Tenke, Democratic Republic of Congo
Modelling of pit water qualities form geochemical testwork and assessment of possible water quality impact from the limestone quarry in comparison to WHO drinking water guidelines.
Manganese Metal Company – Pappas
Quarry and Kingstone Vale Residue Disposal
Facilities Nelspruit, South Africa
Involved in geochemical characterisation & modelling to assess the fate, transport and bio-geochemical process that change the distribution and mobilisation of manganese, sulphate and ammonia to the receiving environment.
Manganese Metal Company – Nelspruit
and Krugerdorp operations
Nelspruit, South Africa
Project Manager for environmental monitoring programme. Co-ordination and managing specialist studies (biomonitoring, soil, ecology, surface water and groundwater) for monitoring periods 2008 and 2009. Review of the 2011 Krugersdorp monitoring programme.
Emalaheni Mine Water Project
Witbank, South Africa
Development of the source-term model used as input into numerical groundwater model. The task involved data analysis and reporting of gypsum and metal sludge residue.
Sappi Ngodwana Mill Source-term Study
Johannesburg, South Africa
Technical input to the IWWMP update and involved, detailed sampling, conceptualisation and flow and geochemical modelling. The flow modelling was conducted for a hetergenous vadose zone considering the clay lenses responsible for attenuation. Colum experiements for Kd values were conducted to calibrate the contaminant transport model (Consim). The source-term mass transfer prediction was used as input into the numerical groundwater model.
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Curriculum Vitae KOOVILA NAICKER
Heidelberg Johannesburg, South
Africa
Technical input to the EMPR. Geochemical modelling of the pit water qualities for the opencast and underground sections of the mine was predicted using static and kinetic test work. A block model of the distribution of potentially acid generating and acid neutralisation waste rock in the deposit to influence a selective handling strategy.
Welkom Johannesburg, South
Africa
Chemometric and geochemical modelling and assessment of chemical composition, potential mobility and toxicity of elements in water, sediment and soil of the Brakpan and Dankbaar evaporative gold pans, Welkom (2002-2003)
Sappi Enstra Johannesburg, South
Africa
Source term inventory and source term model development for The Sappi Fine Paper Mill (Springs). The project involved development of a sampling protocol, sample collection of various waste sources including the plant and Cowles Dam. Development of time series mass load model that was used as input into numerical ground water model. Also involved in the water quality report to DWAF for the Sappi surface water and groundwater monitoring programme.
Black Mountain Northern Cape, South
Africa
Source term characterisation study for operational and closure phases of the TSF and return water dam. The project evolved sample collection, static test, kinetic test and the development of series mass load model that was used as input into numerical ground water model.
TRAINING
Contaminated Site Fundamentals: Investigation, Regulations, Risk Assessment, and Remediation - Professional Webinar Geoenvirologic, 17 April 2014
Project Management Fundamentals Training Course. South Africa Golder U course, 16-19 October 2012
Environmental Geochemistry for Modern Mining Society of Economic Geologist - Bob Seal and Kirk Nordstrom, 29-30 October 2010
PHREEQC-2 Course, Lisbon Portugal C.A.J Appelo and V.E.A Post , 22 - 26 September 2007
Introduction to Geochemical Modelling Tools: Equilibrium and Transport Applications, Colorado USA Mahoney Geochemical Consulting LLC, , 6 - 10 June 2011
SUPPLEMENTAL SKILLS
Project Management
Completed Golder PM1 course successfully 16 - 19 October 2012.
7
Curriculum Vitae KOOVILA NAICKER
PROFESSIONAL AFFILIATIONS
Member of WRC Reference Group K5/2231: An industrial ecology approach to sulphide containing mineral wastes to minimise ARD formation: characterising potential for ARD, design for disposal and extraction of products with value
Member of International Mine Water Association (IMWA)
Member South African Council for Natural Scientific Professions - SACNASP. No 400124/08
PUBLICATIONS
Other K.Naicker and K. Lupankwa. Prediction of seepage from a platinum-group metals tailings storage facility. Proceeding of the IMWA and ICARD Conference, Santiago, Chile, April 2015
K.Naicker, K. Lupankwa, N. Bezuidenhout, L. Ocheing. Pit load modelling for a
completely backfilled opencast coal mine in the Karoo-Basin South Africa. Proceedings of the WISA 2014 Biennial Conference, Mpumalanga, South Africa, 28th May 2014.
K.Naicker, K.Lupankwa, N. Bezuidenhout and L.Ocheing (2013) Contaminant
load estimate for a backfilled opencast coal mine in Karoo-basin, South Africa. Presented at the Groundwater Division - GGSA, Durban South Africa, 19th September 2013.
K Naicker, N Bezuidenhout, T Harck(2012) Geochemical and hydrogeochemical
considerations from backfilling of discard and ash. Proceedings from 9th International Conference on Acid Rock Drainage (ICARD), 20-26 May 2012, Ottawa, Ontario, Canada.
Govender K, Bezuidenhout N, Van Zyl A, Rousseau P (2009) Prediction of
seepage emanating from a TSF in arid climate. Proceedings from the Securing the Future and Eigth International Conference on Acid Rock Drainage (ICARD). 23- 26 June 2009, Skellftea, Sweden.
Naicker K, Cukrowska E and McCarthy T.S (2003) Acid mine drainage arising
from gold mining in Johannesburg, South Africa and environs. Environmental pollution 122 pp 29-40.
Chimuka L, Cukrowska E, Soko L and Naicker K (2003) Supported liquid
membrane extraction as a selective sample preparation technique in monitoring uranium in complex matrix samples. Jounal of Separation Science, 2003, 26, 601.
Cukrowska, E.M. Naicker, K. Viljoen, M. (2003) Ion mobility based on sequential
column leaching of South African gold mine tailings dump and chemometric evaluation, Journal of Environmental Monitoring. Chemosphere, 56 (2004) 39-50.
L.Chimuka, E Cukrowska, L.Soko, K.Naicker (2003) Supported liquid membrane extraction as a selective sample preparation technique in monitoring Uranium in
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Curriculum Vitae KOOVILA NAICKER
complex matrix. J.Sep. Sci. 4(3) (2003).
T. Kowalkowski, S. J. Piketh, E. Cukrowska, K. Govender (2004) Statistical evaluation of aerosol data from Ben Macdhui mountain (South Africa), Accepted -Water, Air and Soil Pollution with minor revision.
Ewa Cukrowska, K. Naicker, M. Viljoen: Column leaching and chemometric evaluation of the mobility of toxic elements in gold mine polluted land. Proceedings of SWEMP 2002, R. Ciccu (Ed), ISNN 88-900895-0-4, Cagliari, Sardinia, Italy, 7-10 October 2002, p1075 - 1082.
Koovila Naicker, Ewa Cukrowska, Terence McCarthy: Modelling of acid mine drainage arising from gold mine activity. Proceedings of SWEMP 2002, R. Ciccu (Ed), ISNN 88-900895-0-4, Cagliari, Sardinia, Italy, 7-10 October 2002, p 745 - 752.
K.Govender, E Cukrowska, T.S.McCarthy Modelling and chemometric evaluation of acid mine drainage from gold mining in Johannesburg, South Africa. 8th International congress on Mine water and the environment, Johannesburg, S.A 19th-22nd October 2003.
K.Govender, E. Cukrowska, H. Tutu, M. Viljoen, N.F Mphephu: Modelling of water quality data influence by gold mining in Johannesburg, SA. Proceedings of SWEMP 2004, Antalya, Turkey, 17-20 May 2004, pp 439-444.
H. Tutu, E. Cukrowska, K. Govender, T. S. McCarthy, M. J. Viljoen, N. F. Mphephu: determination and modeling of geochemical speciation of uranium in gold mine polluted land in the Central Rand Goldfield in SA. Proceedings of SWEMP 2004, Antalya, Turkey, 17-20 May 2004, pp 487-492.
N.F.Mphephu, M.Viljoen, E.Cukrowska, K.Govender, H.Tutu Mineralogy and geochemistry of mine tailings in relation to water pollution on the Central Rand, South Africa.Environmental issues and waste management in energy and mineral production Proceedings of SWEMP 2004, Antalya, Turkey, 17-20 May 2004.
K. Govender, A. van Zyl, N. Bezuidenhout Prediction of Seepage Emanating from a Residue Disposal Facility for Various Closure Options, Johannesburg, South Africa. Mine Closure Conference, 14-17 October, 2008.
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