Download pdf - Revuboe Road and Stormwater

7/27/2019 Revuboe Road and Stormwater

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TABLE OF CONTENTS

1.General......................................................................................................................................... 21.1Objective..................................................................................................................................... 21.2Design work................................................................................................................................21.2.1Access roads........................................................................................................................... 21.2.2Haul roads................................................................................................................................21.2.3Storm water management........................................................................................................31.3Surveys and information requirements.......................................................................................32.Methodology and Scope............................................................................................................... 4

2.1Schematic layout.........................................................................................................................42.2Access roads design...................................................................................................................42.2.1Access roads from public roads...............................................................................................42.2.2Internal access roads...............................................................................................................52.2.3Internal maintenance roads.....................................................................................................52.3Haul road design.........................................................................................................................52.4Storm water management design...............................................................................................72.5Geotechnical investigation..........................................................................................................82.6Topographic survey.................................................................................................................... 82.7Costing........................................................................................................................................83.Annexure 1................................................................................................................................. 10


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1.General1.1 Objective

The objective of the technical proposal for a feasibility study is to produce reports,drawings, and engineering designs for the access roads, haul roads and storm watermanagement associated with the roads. The work will be done to a sufficient level ofdetail to allow capital and operational cost estimates to be done to a reasonable levelof detail.

This proposal defines minimum information requirements and preliminary investigationwork that will be required for detailed design and drawing layouts for the accessroads, haul roads and storm water management. The requirements needs to be co-ordinated with similar requirements for the plant, mine plan and operations, workshopand office facilities, water supply, waste water and sanitation and rail engineering anddesign.

1.2 Design work

1.2.1 Access roads

The design/upgrade of access roads and roads within the plant and office/workshopfacilities (if not included in the design of these facilities) should include the followingelements:

Clearing of road reserves

Geometric design and alignment

Pavement design Earthworks and retaining structures

Storm water management including drainage and culverts

Bridges (If required)

Service accommodation and relocation

Landscaping and vegetation

Traffic control including road signs and markings

Fencing and control of access to road reserve

Facilities where required

1.2.2 Haul roads

The design of haul roads will depend on the mine operations plan but should includethe following elements:

Clearing of road reserves

Geometric design and alignment with emphasis on horizontal and vertical

alignment, curves, safety berms and gradients

Pavement design

Earthworks and retaining structures

Storm water management including drainage and culverts

Bridges (If required)

Service accommodation and relocation Landscaping and vegetation

Traffic control including road signs and markings


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Fencing and control of access to road reserve

Facilities where required

1.2.3 Storm water management

The storm water and drainage design will depend on the overall mine operations planand needs to be integrated in the total water management (water balance). Thedesign of the storm water management and drainage should include the followingelements:

Hydrological survey

Geo-hydrological survey

Assessment of design storms and intensities for different return periods

Assessment of potential run-off for different areas on the property

Culverts and drainage channels

Bridges (if needed)

Sub surface drainage and control

Separation of run-off from clean and dirty areas

Erosion protection and control

Containment areas for dirty water

Exclusion and/or management of surface water run-off in operational areas

Pumping stations and return water pipe lines if required

1.3 Surveys and information requirements

To support the design process, ancillary information will need to be obtained. Thesurveys and information gathering must be coordinated with other design activities.Information and surveys should include but not necessarily limited to the following:

Traffic surveys Estimates of future traffic flows based on the mine operations plan and general

development of the area

Geotechnical surveys

Material source investigations for earthworks

Geological survey (tied to the 2 surveys above and could be sourced from the

exploration drilling that has taken place)

Hydrological survey

Geo-hydrological survey

Rainfall records

Topographic surveys

Climate and vegetation (input from environmental studies)

Aerial and satellite photographs/images

Existing charts and maps

Cadastral information (if needed)

Health, safety and quality requirements

Mozambiquecan laws, regulations, standards and specifications

Human resource requirements


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2.Methodology and Scope2.1 Schematic layout

Figure 1 Schematic layout of haul roads and river diversions

Legend:Blue river diversionPurple haul road

Access roads are not indicated in the layout above. The river diversion will bediscussed in a separate document. The haul roads are extensive but the lack oftopographical detail precludes a more detail approach.

2.2 Access roads design

A number of access and internal roads will be required for the project. These shouldinclude but is not limited to the following:

Access roads from existing public roads

Internal access roads between the plant, workshops and office facilities

Internal maintenance roads

2.2.1 Access roads from public roads

The design of the roads will be influenced and subject to the standards, specificationsand requirements of the Mozambique Roads Authority.

Mozambique is a member of the Southern African Development Community (SADC).SADC has instituted a number of initiatives of which the SATTC-TU (Southern African

Transport and Telecommunications Committee Transport Utility?) is one. TheSATTC-TU has developed and is busy developing standards and specifications forapplication in the SADC countries. A number of these documents exist and will be


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utilised as references for the design of access roads. Further standards,specifications and guidelines are provided by ASANRA (Association of SouthernAfrican National Road Agencies).

The standards and specifications mentioned above is based to a large extent on theSouth African TRH (Technical Recommendations for Highways) and TMH (TechnicalMethods for Highways) documents and will be utilised for as additional sources for the

access road designs.

The geometric design will be based on the Geometric Design standard of SATTC-TUand the South African Geometric Design Manual.

Pavement design will be based on a mechanistic design approach as contained in theTRH 4 Structural design of inter-urban and rural roads as modified forMozambique requirements. It is recommended that the access road be surfaced.Software applications Mepads, trafPADS and WinDCP will be utilised in the design.

Drainage and storm water management for the access roads will be in accordancewith the SANRAL (South African National Roads Agency Limited) Drainage Manual

as modified by the SATTC-TU documents.

Prerequisites for the access road design will consist of traffic survey, topographicalsurvey, geotechnical survey, hydrological survey and material source investigation.

2.2.2 Internal access roads

Internal access roads will be designed on the same basis as the external accessroads utilising the same methodologies, standards and specifications but with dueregard for the vehicle traffic as estimated from the mine operations plan.

It is recommended that the internal access roads be surfaced for safety, economical

and maintenance reasons.

The same prerequisites as for the external access roads will be applicable.

2.2.3 Internal maintenance roads

Maintenance roads will be required for access to plant and facilities that cannot bereached from internal access roads e.g. pumping stations, magazines, conveyors etc.

The geometric design will be based on the Geometric Design standard of SATTC-TUand TMH 4 geometric design standards for rural two lane two way roads and TRH17 Geometric design of rural roads.

Pavement design will be based on a mechanistic design approach as contained in theTRH 20 Structural design, construction and maintenance of unpaved roads asmodified for Mozambique requirements.

Drainage and storm water management for the maintenance roads will be inaccordance with TRH 20 as modified by the SATTC-TU documents.

Prerequisites for the maintenance road design will consist of topographical survey,geotechnical survey, hydrological survey and material source investigation.

2.3 Haul road design

Haul roads are an important element of the mine operations and must contribute toeffective and efficient transport of the coal from the mine to the plant area. These


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haul roads tend to be the lifeline of the production system and road problems willimmediately impact on the productivity and/or costs of the mine.

The design of the haul roads depend on the mine operations plan regarding vehiclesizes and number that will be utilised and on the availability of construction material.

Material selection for the haul road layers will be done in accordance with TRH 14

Guidelines for road construction materials as modified for site conditions and materialavailability.

Geometric and structural design and storm water management will be done inaccordance with best practices as established in the design of various coal mine haulroads with reference to the following publications:

Guidelines for Mine Haul Road design - Dwayne D. Tannant & Bruce

Regensburg

Designing and managing unpaved opencast mine haul roads for optimum

performance - R. J. Thompson and A. T. Visser

Design of Surface Mine Haulage Roads - A Manual - Walter W. Kaufman and

James C. Ault

Figure 2 below show typical structural designs for two different sizes of vehicles.

Figure 2 Typical structural designs for haul roads


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Prerequisites for the haul road design will consist of mine operations plan,topographical survey, geotechnical survey, hydrological survey and material sourceinvestigation.

2.4 Storm water management design

Storm water management will need to be integrated with the water balance for thetotal operations.

Drainage and storm water management for the roads have been discussed in therelevant sections.

Rainfall and storm records for the area need to be acquired as part of the hydrologicalsurvey. Subsurface drainage will be determined from the geo-hydrological survey,environmental studies and the geological survey.

Figure 3 below provides high level data from Tete Township which is close to the site.

Figure 3 Average temperatures and rainfall


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Historical Meteorological and Climatological Data for Mozambique (1909-1968) can beobtained from the NOAA Central Library Climate Data Imaging Project for Mozambique.This data can be used for modelling of rainfall events, design intensities and run-off forvarious return periods. A 30 year data set of rainfall events is available from the RainfallExtraction Utility for Southern Africa and monthly data is appended in Annexure 1.

The EPA SWMM, HEC HMS, HEC SSP, rational method and maximum designflood software and techniques will be utilised in the design of storm watermanagement. The drainage manuals referred in the sections on road design will beused as supplementary sources of information and methodologies.

Prerequisites for the storm water management design will consist of topographicalsurvey, hydrological survey and information investigation.

2.5 Geotechnical investigation

A geotechnical investigation is of the utmost importance and the methodologyproposed by Arcus Gibb in Section 3.5 of their document Revuboe Mine ProjectFeasibility Study Rail Proposal should be implemented.

2.6 Topographic survey

An aerial topographic survey followed by detail conventional surveys is an important

prerequisite for the proposals.

2.7 Costing

Due to the many unknown parameters it is almost impossible to provide ballpark costestimates within an acceptable uncertainty envelope.

The cost of the roads depend on many factors such as local labour cost, materialavailability and cost, design standards etc to name but a few.

As an example the following costs from some recent projects show the wide varianceand uncertainty;

Access roads R 500 000 to R 2.5 million per km according to geometry, standardsand material.


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Haul roads R 15 million to R 30 million per km depending on all the local factors.

Gravel roads R 50 000 to R 1.5 million per km according to function.

It is not possible to venture any cost estimate on storm water management as theunknown variables are too many.


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3.Annexure 1Rainfall data Rainfall extraction utility

Mean monthly Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann

Chosen location -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -999.0

Climate station -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -99.9 -999.0

Adjustment fact 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.0001.000

9 1952 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M 2.0 28.4 71.2 107.4

209.0U

9 1953 306.6 298.6 74.8 12.9 .7 3.3 4.9 .0 6.4 .0 59.2 281.5 1048.9

9 1954 64.0 102.0 13.3 3.2 .1 .0 1.4 .0 .9 10.8 83.1 187.8 466.6

9 1955 181.6 176.3 8.3 -99.9M .0 1.9 4.3 .7 5.0 2.0 89.6 174.7 644.4U

9 1956 54.5 214.3 43.4 46.4 .5 3.8 .2 .0 .0 .0 152.2 137.4 652.7

9 1957 147.1 128.0 63.4 65.8 4.2 1.6 .0 .0 .0 1.2 37.2 86.9 535.4

9 1958 230.3 273.8 60.9 .4 .0 15.0 .4 6.8 9.6 .1 58.0 83.2 738.5

9 1959 163.9 224.0 8.0 .6 .0 7.2 5.1 20.8 .0 2.1 54.8 131.1 617.6

9 1960 106.2 83.3 169.5 .4 2.4 13.5 3.8 .0 8.0 2.5 16.6 310.2 716.4

9 1961 147.3 97.0 106.1 15.9 1.7 .0 5.8 1.6 .2 .6 49.8 54.5 480.5

9 1962 367.9 58.8 84.8 25.1 3.8 1.4 3.2 1.3 .1 2.3 86.0 248.7 883.4

9 1963 53.1 289.3 40.9 5.8 4.3 7.0 4.4 .0 .0 .8 50.7 45.2 501.5

9 1964 190.9 17.5 13.4 .0 .3 .3 3.8 5.0 .1 .0 56.9 128.6 416.8

9 1965 130.7 209.6 119.1 9.6 2.7 6.3 .3 .8 3.0 13.1 6.6 83.6 585.4

9 1966 133.1 350.6 84.4 .7 .3 4.0 5.7 .0 .7 1.8 31.9 63.5 676.7

9 1967 191.6 58.2 348.0 4.8 3.1 1.1 .9 9.0 1.5 .0 49.9 56.3 724.4

9 1968 172.5 137.9 15.6 27.1 4.6 9.5 .0 1.0 .3 .0 26.2 140.3 535.0

9 1969 194.5 56.3 159.5 21.8 .0 .5 1.8 3.6 .0 14.9 32.9 344.2 830.0

9 1970 99.9 68.9 8.8 17.2 .3 1.7 1.3 .0 .0 .0 136.4 151.2 485.7

9 1971 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U


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9 1972 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1973 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1974 170.4 210.3 62.1 54.0 21.0 .7 3.4 15.6 .3 17.9 117.2 247.6 920.5

9 1975 98.7 122.1 38.3 3.2 .7 4.1 .2 .2 .0 90.6 38.1 132.2 528.4

9 1976 89.4 171.0 194.4 12.4 34.0 1.1 .9 .0 .0 5.8 7.3 105.8 622.1

9 1977 113.0 145.6 145.3 1.7 .0 1.1 .0 4.1 5.8 .4 74.2 171.1 662.3

9 1978 331.7 95.5 227.4 15.3 .3 10.0 6.0 .0 .0 .0 11.5 182.1 879.8

9 1979 48.4 88.7 120.3 3.4 .1 11.2 1.0 .0 .3 7.5 69.8 84.2 434.9

9 1980 163.3 111.6 53.5 32.6 3.0 1.7 6.9 .8 2.0 .8 21.0 156.6 553.8

9 1981 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1982 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1983 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1984 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1985 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1986 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1987 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1988 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1989 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1990 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M-99.9M -99.9U

9 1991 110.1 204.5 47.6 25.8 .9 .3 1.0 .4 .0 17.7 34.2 91.2 533.7

9 1992 -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M -99.9M .0 .0 80.8 -99.9M80.8U

9 1993 227.5 217.0 15.0 20.1 .0 2.2 2.7 1.8 .0 1.9 108.0 48.9 645.1

9 1994 116.0 49.8 30.3 2.4 .0 .0 .9 .0 3.2 82.8 18.4 71.4 375.2


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9 1995 181.2 8.6 17.9 .6 .3 1.6 .0 .4 .0 15.6 1.8 354.3 582.3

9 1996 85.8 199.1 47.5 4.8 25.7 7.0 9.1 .0 .0 12.0 10.5 141.8 543.3

9 1997 236.0 418.5 105.7 174.6 .0 .2 5.6 .2 5.6 8.7 36.0 89.1 1080.2

9 1998 -99.9M -99.9M 24.5 1.6 .0 1.1 .6 2.1 .0 .1 116.9 272.5 419.4U

9 1999 292.1 138.9 62.8 6.1 .5 4.2 6.0 .2 -99.9M -99.9M -99.9M -99.9M 510.8U