28 February 2017 ATTENTION: MR HENNIE WOOD AND MS MAGGIE VON RONGE NORTHAM BOOYSENDAL CC: AMANDA PYPER AMEC FOSTER WHEELER NOTE FOR THE RECORD

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1 Project Reference: File Ref Erosion & Silt Management NFTR Rev1 28 February 2017 PROJECT: Booysendal South EIA Hydrology Specialist Study CLIENT: Amec Foster Wheeler ORDER No: 2338/9149/1294 ATTENTION: MR HENNIE WOOD AND MS MAGGIE VON RONGE NORTHAM BOOYSENDAL CC: AMANDA PYPER AMEC FOSTER WHEELER NOTE FOR THE RECORD BOOYSENDAL CENTRAL CONSTRUCTION PHASE EROSION CONTROL AND SILT MANAGEMENT 1. INTRODUCTION During a site visit on 13 October 2016, as part of an EIA Hydrological Study, earthworks were observed in the vicinity of the new box cut (Booysendaal Central): approx. latitude: , longitude: , and it was noted that a large area of vegetation had been cleared and topsoil disturbed, exposing a large area of loose material, susceptible to erosion in very close proximity to the Groot Dwars River. At the time of the site visit, it was not apparent that sufficiently robust silt management measures were in place to prevent eroded material from washing into the Groot Dwars River. In addition to any sediment loading to the river and associated water quality impacts, mobilised sediment would be transported via the river to De Brochen dam, and may cause water quality issues in the dam and/or may reduce the capacity of the dam. It was recommended that a review of the contractor s erosion protection and silt management measures and/or relevant method statements be undertaken to ensure that environmental impacts associated with the earthworks program are managed in accordance with best practice. Amec Foster Wheeler (AFW) acting on behalf of Northam Booysendal requested SLR Consulting Ltd (SLR) to undertake an independent review of erosion protection and silt management measures being implemented during the construction activities, and recommend improvements where needed. The role of various parties is as follows: Northam Booysendal (Northam) Client and Mine Operator Amec Foster Wheeler (AFW) EIA Consultant

2 SLR Consulting (Africa) (Pty) Ltd Page 2 DRA Global (DRA) EPCM Manager WBHO Construction Contractor SLR Consulting Ltd (SLR) Hydrologist for EIA 2. SCOPE OF WORK In discussion with Northam and AFW, the following scope of work was developed as part of the Independent Review of Erosion Protection and Silt Management Measures: 1. Review: Contractors method statements, action plans, and proposed layout of the new box cut and associated infrastructure. The documents reviewed are listed below. Stormwater Technical Report Permanent Road: Everest to Booysendal (SNA, August 2016). Booysendal Central FS. Block Plan and 100yr Flood-Line (PDF Figure) Dwg No. M G005. (DRA, ). SHEQ Specification 101 v4 (Northam, ). Environmental Construction Requirements v1 (Northam, 2016). WBHO Erosion Protection and Silt Management Measures (WBHO, ). 2. Site Visit: Document existing stormwater and silt control measures, in discussion with contractor, and identify opportunities for improvement. 3. Report: Letter report with findings and high level recommendations. 3. DOCUMENT REVIEW The SNA report outlines the requirement for, and suggested contents of, an Erosion and Sediment Control Plan and various relevant requirements are outlined with Northam s SHEQ and Environmental Construction Requirements documents. As part of the review process SLR requested copies of the EPC Manager and/or Contractor s method statements (or similar documentation) for Erosion Control and Silt Management, but none were provided. At the request of DRA, WBHO had developed an action plan to implement various measures as outlined in their document. 4. SITE VISIT Following review of the above listed documents, SLR visited the site on 16 January The site visit involved the following: Kick Off Meeting: introductions, discussion of construction works to date, recap of recent issues experienced, and confirm agenda for site inspections. Site Inspection: the main objective of the site inspection visit was to see the impacts that the ongoing construction is causing in terms of erosion, identification of hot spots of erosion during wet weather conditions, discuss management measures already in-place, identify areas for improvement. Concluding Meeting: to discuss findings, recommendations, and identify potential risks and management strategies going forward. Personnel represented during the meeting and site inspection were as follows: Northam: o Hennie Woods SHEQ Manager o Maggie Von Ronge Environmental Officer

3 SLR Consulting (Africa) (Pty) Ltd Page 3 o Dirk Hattingh Environmental Officer DRA: o Donal Gasper SHEQ Manager o Renier Troskie Construction Manager o Josias Oberholster Civil Engineer SLR: o Paul Klimczak Senior Hydrologist o Anthony Singo Junior Hydrologist 4.1. KICK OFF MEETING It was noted that the construction area had experienced numerous problems with erosion and silt especially during heavy rainfall events in December and January. Silt had washed into the Groot Dwars at several locations, and severe erosion was experienced in a few locations. Building on WBHO s action plan dated , DRA had developed an action plan listing over 30 locations where remedial actions were required, each location was ranked in terms of environmental risk, measures were recommended, progress measured as % complete, and target dates set which prioritised works in highest risk areas SITE INSPECTION The locations visited, findings and recommendations are presented in the Table below and photographs are presented in Appendix A. No. X Y Description Measures in Place Further Recommendations (m UTM) (m UTM) Road passes through Groot Dwars river and None Regular cross drains / berms perpendicular to road direction and suffers erosion slope recommended, to convey problems along the length of the road, causing silt to be washed into river. runoff into roadside vegetation at regular intervals, reducing volumes and velocity of runoff flowing along the road Temporary road which runs parallel with river culverts beneath permanent road which convey a large flow during storm events Silt fence and bunds along road Crushed rock placed on downstream end of culverts Settlement basin created with perimeter bunds between road and river Box Cut Permanent diversion channels to convey stormwater around the boxcut, and level terracing means erosion and silt problems experienced in this area are minimal Topsoil stockpile Bund adjacent to watercourse crossing Support of silt fence with rocks and maintenance. Crushed rocks along road surface recommended to improve drainage, and prevent vehicles from continuously disturbing muddy road surface where water ponds. Extend crushed rock and direct flow towards settlement basin (below) Requires spillways in lowest point of bund, to prevent erosion and potential breach if water levels exceed bund height during extended storm event Ongoing monitoring Create berm or channel required along the toe to drain silty runoff into densely vegetated area adjacent to watercourse.

4 SLR Consulting (Africa) (Pty) Ltd Page 4 No. X Y Description Measures in Place Further Recommendations (m UTM) (m UTM) Watercourse Crossing Crushed rock fill is filtering out silt prior to river. Continue to raise this area with crushed rock, creating a basin which causes runoff to filter through crushed rock, removing silt Drainage line flows across permanent road Permanent road is extended into drainage line. Crushed rock placed on outside of embankment to prevent erosion. None upstream of watercourse. Permanent culverts to be installed ASAP, and outside of embankment stabilised by benching and hydroseeding, or additional crushed rock. Ideally re-routing road, out of the drainage line (this drains a large catchment, and flows and velocities will be significant). As a minimum erosion protection will be needed at the toe of the embankment. This is likely to be at permanent risk of erosion unless sufficiently robust measures are implemented CONCLUDING MEETING Various remedial measures had been implemented at the site and were successful in controlling erosion and silt management in certain areas. Improvements on existing measures were noted and additional measures proposed for some areas. The positive impacts associated with future works were discussed (e.g. permanent drainage and culverts, benching and hydroseeding etc). The importance for monitoring and maintenance was noted. 5. GENERAL FINDINGS AND RECOMMENDATIONS It was concluded that there are many erosion and silt control measures in place across the construction sites. The effectiveness of these measures and the requirement for additional measure must be routinely monitored and reported on as the construction program progresses. Hydroseeding and benching of the permanent road embankments, should be prioritised in areas closest to the river and where there is minimal vegetated buffer in place between the road and the river. Permanent drainage will be installed along the permanent road, formalising management of stormwater in these areas. A series of cross drain (culverts beneath the road surface) will soon be installed to convey flow from the side drains along the hillside of the road to the outside / road shoulder and into the vegetated slopes below. On average cross drains will be installed every 200m allowing for dispersion of runoff from the road surface, rather than higher flows at fewer outfall points which would cause more erosion downstream. It is recommended that erosion and silt management is considered carefully and monitored regularly during extension of the permanent road onto the eastern side of the valley. Most effective means of erosion and silt management is to minimise disturbance of existing vegetation and topsoils, divert upstream runoff around earthworks areas, disperse silty runoff into vegetated areas, and retaining vegetated buffers between earthworks areas and any watercourses or drainage line. A list of potential management measures is presented in Appendix B. Consideration was given to creating a settlement lagoon within the Groot Dwars downstream of the earthworks area but this was considered impractical for numerous reasons. Groot Dwars

5 SLR Consulting (Africa) (Pty) Ltd Page 5 catchment upstream of the Booysendal Central mine is approximately 50km 2, flows are high and providing sufficient residence time to allow for settlement of suspended solids would require an infeasibly large footprint area. Constructing such a facility would heavily impact on the natural flow regime of the river. Source control will be much more effective for controlling silt levels than treating the river downstream of the works area. 6. MONITORING AND PERFOMANCE REVIEW It must be acknowledged that earthworks programs such as that at Booysendal represent dynamic conditions for erosion and silt, and consequently management measures required at a particular location or during a specific construction activity may need to be upgraded a few weeks later, or may not even be required at all. Furthermore, the performance of measures may change over time and in response to individual rainfall events, as such regular monitoring and maintenance of measures is required. It is recommended that during and immediately after rainfall events, the problem areas identified above are monitored to assess the performance of measures in place, and to identify any new areas of erosion attributable to recent construction activities. 7. CONCLUSION It is concluded that various measures are currently in place, although ongoing monitoring of performance and maintenance is essential. Substantial reduction in erosion and silt will be expected when permanent drainage is installed along the new road, and when benching and hydroseeding is undertaken along embankments. It is essential that future works are carefully considered to minimise disturbance of vegetation and topsoil. Should you have any queries regarding the above, please do not hesitate to contact me. Yours sincerely Paul Klimczak, PrSciNat Senior Hydrologist / Author Steve Van Niekerk, PrEng Senior Engineer / Reviewer

6 SLR Consulting (Africa) (Pty) Ltd Page 6 APPENDIX A: SITE PHOTOS Location 2 ( m; m) Showing waterlogged mud regularly disturbed by vehicles, raising levels with crushed rocks is recommended to improve drainage, raise levels along the road surface and prevent vehicles from continuously disturbing muddy road surface where water ponds. Location 2 ( m; ) Showing silt fence to be extended laterally to tie in with roadside bunds. Showing silt fences to be extended laterally and supported with rocks where necessary.

7 SLR Consulting (Africa) (Pty) Ltd Page 7 Location 3 ( m; ) Two culverts beneath permanent road, which currnently drain a very large catchmnent. Crushed rocks placed on downstream end to prevent erosion. Bund created adjacent to river to contain silty stormwater from the access road and permananent road, and allow settlement of silt prior to discharge, or allow infiltration of stormwater to ground. Needs a spillway, to prevent the bund being washed away if overtopped. Location 5 ( m; m) Topsoil stockpile adjacent to tributary of Groot-Dwars, constant access needed. Berm or channel required along the toe to drain silty runoff into densely vegetated area adjacent to watercourse. Densely vegetated area to which runoff will be diverted.

8 SLR Consulting (Africa) (Pty) Ltd Page 8 Location 6 ( m; m) Showing watercourse crossing and crushed rock being used to elevate road level, which has filtered out of lot of silt (filling gaps between rock fill). Location 7 ( m; m) Currently in construction main road to cut box. Drainage line flows onto construction works of permanent road, requires installation of permanent drainage (2 x culverts) ASAP.

9 SLR Consulting (Africa) (Pty) Ltd Page 9 Location 7 ( m; m) Boulders and crushed rock, placed on embankment to protect against erosion when flow experienced along the drainage line. Location 8 ( m; m) Embankment of road is extended into the watercourse and suffers erosion during each storm event. Erosion protection measures required along road embankment.

10 SLR Consulting (Africa) (Pty) Ltd APPENDIX A: REVIEW OF AVAILABLE EROSION PROTECTION AND SILT MANAGEMENT MEASURES The following management measures may be considered to reduce erosion and control silt: Management Measure Minimising Disturbance Phasing / Scheduling Source control Protection Stockpiles Haul Road Design of Description Page The single most effective source control measures is to minimise disturbance of vegetation and soils. Carefully considered phasing of earthworks can minimise the footprint at risk of erosion at any given time, or schedule works according to the season e.g. undertake works which cause most disturbance of vegetation and topsoils during the dry season, and revegetate, hydroseed, install permanent drainage etc before the wet season commences. The protection of exposed surfaces from the erosive energy of rain splash and surface runoff flow need to be the major factors of controlling runoff. Topsoiling in conjunction with one or more of the following: seeding, hydroseeding, erosion control blankets, turf reinforcement matting, riprap, aggregate cover and paving can be effective for source control. Stockpiles should be located away from the drainage lines and watercourses. Diversion of stormwater from upstream areas around the stockpile should be implemented. Benching, and roughening will reduce runoff, and encourage revegetation of stockpiles. Access road, parking and haul roads need to be stabilised and maintained to minimise generation of sediment during wet weather conditions. Ditches should be constructed on either side, or on the downslope side, of haul roads to channel water to a treatment area Mulching and Binders Mulches include organic materials, straw, wood chips, bark or other wood fibres and gravel and are used to stabilise or protect cleared or seeded areas, either temporarily or permanently. Binders can be applied directly to soil or over mulch layer, usually can be mixed with water then sprayed on the slope. For maintenance of these two weekly inspections need to be considered. Seeding and Planting Seeding and Planting on slopes minimize erosion by stabilising soils and reducing velocity of runoff as it flows down the slope. The requirement for irrigation and fertilisation should be considered. Vegetated Buffers Retention of a vegetated buffer down gradient of any earthworks will filter out silt and prevent further erosion of soil through soil stabilization. Geotextiles and mats These help to stabilisation of soils and can be applied to disturbed soils where vegetation cover is cleared. These can be used temporarily until vegetation is established. Also helps to reduce the velocity of the runoff from up the slope. Diversion/Temporary drains Slope drains Check dams and sediment traps Silt fence Level spreader Earth dikes, drainage swales and ditches Slope Roughening and Benching Plastic sheeting Outlet protection Riprap Diverting upslope runoff, around or across the site, this is crucial in terms of collecting and channelling silty runoff downslope of the site to prevent it leaving the site and end up polluting river. This can be achieved through a temporary pipe or lined channel that drains the top of a slope runoff to a stable discharge point at the bottom of the slope without causing erosion. This requires bunds along the top edges of slope to direct water to an inlet. These are the small temporary dams that reduce the velocity of concentrated runoff. Wood or rocks filter bunds may be used to construct check dams. This reduces the flow velocity and allows sediments to settle in such a way it end up not flowing through with water. These remove sediments in runoff by slowing runoff flow, causing sediments to drop out of suspension and by filtering out silt as water passes through. This is not effective on concentrated or channelized flow. It should be placed along horizontal contour and perpendicular to the direction of sheet slow. The purpose of this is to convert a concentrated flow into a sheet flow in order to discharge if into low lying area where there is vegetation without causing erosion These are the structures lined to intercept, divert and convey surface runoff around or through the project site in a non-erosive manner. Compared against smooth, compacted soils slopes, roughening and benching of exposed soils encourages infiltration (i.e. reduced reduces), reduces velocity of runoff (i.e. reduces erosion), and allows vegetation to establish quicker. Provides immediate protection to soil slopes from erosion. Plastic sheeting can also help in reducing the flow velocity especially at the slope where there is vegetation. Outlet protection reduces the speed of concentrated runoff flow, thereby preventing scour at conveyance outlets. By dissipating energy, outlet protection lowers the potential for downstream erosion. Outlet protection includes riprap-lined basins, concrete aprons, and settling basins. Outlet protection prevents scour at storm water outlets, and minimizes the potential for downstream erosion at some stage can be a place where the sediments settles at. This can be done on the banks of temporary channels and straight on channel or at the whole slope, this can be really be effective on reducing the velocity of flow at the end the will be low or no sediments that flows with water down slope. 10

11 SLR Consulting (Africa) (Pty) Ltd In addition to management measures, various treatment measures can be considered downstream of any construction activities, as listed below: Page 11 Treatment Measures Pump to grassland Settlement ponds Filtration Settlement tanks Flocculation Description This is effectively a treatment-and-disposal solution, but cannot be considered as a permanent solution due the fact that it is not appropriate for long-term use. It is more suitable for unpolluted water, the method s performance depends mainly on infiltration rate and the permeability of the ground as well as the small volume pumped interval. Site runoff or water pumped from excavations is channelled into a pond constructed specifically to allow any suspended solids to settle out before discharge. Settlement ponds may not be practicable for all linear sites, as they can require a relatively large land take. Ideally, suitable areas of land should be identified at an early stage in the project. Filtration can be achieved by routine sediment traps as water flows across site or along channels, or by pumping water through filtration material which can include a tank filled with fine single-size aggregate (5 10 mm), geotextile or straw bales. Settlement tanks are purpose-made structures to contain water for the removal of suspended solids. They operate on similar principles to settlement ponds but are portable and smaller. The tanks generally have a series of baffles over which water flows. This is often the optimum solution for treating large volumes of silty water where space is restricted or particle size is too small to settle out, and is therefore highly suitable for use on linear schemes. Very fine particles (typically less than mm) will never settle out of liquid without some chemical addition.