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REMEDIATE
Reuse of extractive waste from abandoned mine site to restore land sustainability: A case study in Campello Monti, NW Italy
Neha Mehta, Giovanna Antonella Dino, Iride Passarella, Franco Ajmone Marsan,
Domenico Antonio De Luca
19 Sep 2018, Belfast
Mining
Treatment
Mining site
Ore
Minerals
Waste rock
Operating residues
Methodology Environmental impacts Reuse ConclusionsBackground
Extractive waste
Analysis of approximately 1000 abandoned mines across
globe, revealed that 75% of the closed mines had
resources left.
Extractive waste dumps at abandoned mine sites are
sources of contamination but also source of raw materials.
Management of extractive waste requires reducing
environmental impacts along with possible beneficial use.
Work provides holistic approach including geology, soil
chemistry and circular economy. Census of abandoned extraction
sites in Italy (APAT 2006)
Methodology Environmental impacts Reuse ConclusionsBackground
Management
of waste
Site investigation
Resource efficiencyAssessment of
environmental impacts and
human health
Risk analysis
Dressing activities and
analysis
Mobility studies
Total metal concentration
yes
no EW facility exploitation
with benefits
Remediation (exploitation
not beneficial)
Extractive waste
characterization
Extractive waste facility
Presence of harmful
impacts at site
No intervention activity ( onlymonitoring)
yes / no
Reuse
meth
odolo
gy
Background Methodology Environmental impacts Reuse Conclusions
The present study was conducted at
abandoned mining site in Campello Monti,
Piemonte in north west Italy.
Campello Monti (old dressing plant)
Waste rock dump – Campello Monti
Background Environmental impacts
Site settingReuse ConclusionsMethodology
Geographicallocation
Campello Monti is in Italian region of
Piedmont.
Geological Setting
Mafic formationintruded by mantle
peridotites.
Minerals:Chalcopyrite,
pentlandite, pyrrhotite
Hydrography and Hydrogeology
Strona stream
Groundwatercirculation : in fractured rocks, in waste dumps and in mining tunnels
used for extracting metal.
Exploitation activity
About fifteen small Fe-Ni-Cu-(Co) sulphidedeposits occur, in the
area comprised between the Sesia and
Strona valleys.
Nickel exploitationoccurred from 1865 to
1943.
Background Environmental impacts
Site settingReuse ConclusionsMethodology
Background Environmental impacts
Sample locationReuse ConclusionsMethodology
Water samples were found to be
contaminated by Ni.
Soil samples showed Cr, Cu and Ni
contamination.
Waste rocks (<2 mm) showed
concentrations of Co, Cr, Cu and Ni
exceeding the Italian permissible
limits.
Photo taken during water and waste rock sample
collection
Water
Waste rock
Background Environmental impacts
Total concentrationsReuse ConclusionsMethodology
Superficial layer Campello Monti Campello Monti
human health risk Superficial layer Deep layer
Concentration at
source [mg/kg.
d.m.]
Carcinogenic Risk
(RI)
Hazard Quotient
(HQ)
Risk to
groundwater
(RGW)
Risk to
groundwater
(RGW)
Antimony 1.26 --- 0.04 0.05 0.01Arsenic 1.06 2.73 x 10-6 0.05 0.034 0.07Beryllium 0.05 3.28 x 10-11 3.51 x 10-4 1.6 x 10-4 3.2 x 10-4
Cadmium 0.03 1.74 x 10-11 9.62 x 10-4 9.46 x 10-4 1.9 x 10-3
Cobalt 18.9 --- 0.8 0.08 0.16Chromium (total) 160 --- 3.05 x 10-3 1.7x 10-5 3.4 x 10-5
Nickel 427 2.88 x 10-8 0.3 3.12 6.24Lead 2.6 --- 9.73 x 10-3 0.003 0.006Copper 173 --- 0.06 0.05 0.09Selenium 0.02 --- 5.26 x 10-5 3.77 x 10-3 0.006Thallium 0.01 --- 0.03 1.18 x 10-3 0.002Vanadium 1.25 --- 0.04 NA NAZinc 9.98 --- 4.37 x 10-4 5.1 x 10-4 1.02 x 10-3
Background Environmental impacts
Risk assessmentReuse ConclusionsMethodology
pH dependence batch leaching test were performed
to study release aspect of contaminants in water, to
further analyze impacts of waste.
Experimental conditions :
Liquid : solid = 10:1
pH = 4, 6, 8, 10, 12
Time = 24 hours
The eluates showed concentration of all the PTEs
analyzed within the permissible limits except Ni.
Background Environmental impacts
Leaching studiesReuse ConclusionsMethodology
Fine fraction was analyzed for its use as additive to soil.
Extractive waste was sieved to obtain the fine fraction (< 2
mm, sieve size)
Experiments were conducted on Lepidium sativum seeds.
Seed germination test
Background and
methodologyEnvironmental impacts Reuse as soil additive
(fine fraction < 2mm)Conclusions
Photos taken after 21 days of growth
Extractive waste was mixed with sand and
compost in different percentages and its effect on
final weight of plants was observed.
Background and
methodologyEnvironmental impacts Reuse as soil additive
(fine fraction < 2mm)ConclusionsBackground and
methodologyEnvironmental impacts
Coarse fraction of waste rocks
and operating residues
Jaw crusher
CrushingSieving
Different sieve sizes
Shaking table
Magnetic separation
Recovery
method
Recovery analysis ( by total metal
content and mineralconent)
Background and
methodologyEnvironmental impacts Recovery from
coarse fraction (> 2mm)
Conclusions
Separates particles on the basis of difference in specific gravities (SG) of particles.
Sincere thanks to Prof. Paola Marini and Dr. Rossana Bellopede,
Politecnico di Torino, for their help for concentrator table and magnetic
separation experiments.
Wet shaking table
Schematic diagram
Background and
methodologyEnvironmental impacts Recovery from
coarse fraction (> 2mm)
Wet shaking table
Conclusions
Recovery % =𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑒𝑥.𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑒 𝑤𝑒𝑖𝑔ℎ𝑡
𝐹𝑒𝑒𝑑 𝑥.𝐹𝑒𝑒𝑑 𝑤𝑒𝑖𝑔ℎ𝑡. 100
Recovery of Co, Cu, Ni and Pd was higher for
size fractions (0-0.5 mm) than 0.5-1 mm.
Recovery % for Ni reached upto 76% for
operating residues.
Background and
methodologyEnvironmental impacts Recovery from
coarse fraction (> 2mm)Wet shaking table
Conclusions
Manual magnetic separation to see the recovery of different
fractions.
Dry low intensity magnetic drum for 0.5-1 mm fraction.
High gravity magnetic separator for 0.063-0.25 mm, 0.25-0.5
mm.
Schematic diagram of High
gravity magnetic separator
Background and
methodologyEnvironmental impacts
Recovery from
coarse fraction (> 2mm)
Magnetic separation
Conclusions
Arsenic was found to cause carcinogenic risk. Ni caused risk to groundwater.
Waste from Campello Monti did not prove harmful to plant growth.
Up to 76% recovery for Ni through wet shaking table.
Up to 52% recovery for Co and Ni through magnetic separation.
The present research shows that the followed approach can be used at otherabandoned mine sites in order to decrease environmental impacts whilegenerating economic benefits.
Background Methodology Environmental impacts Reuse Conclusions
Thanks For Listening
REMEDIATE
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 643087
Project coordinated by the QUESTOR Centre at Queen’s University Belfast www.qub.ac.uk/questor