APPENDIX 17 AQUATIC ECOLOGY AND WETLANDS REPORT FRESHWATER ECOLOGICAL ASSESSMENT AS PART OF THE ENVIRONMENTAL AUTHORISATION AND WATER USE LICENSE APPLICATION PROCESS FOR THE PROPOSED ERPM EXPANSION AREA 2 MINE, BRAKPAN SOUTH, GAUTENG PROVINCE Prepared for Prime Resources Environmental Consultants June 2019 Prepared by: Scientific Aquatic Services Report author: L. Robson (Cand. Sci. Nat) Report reviewers: K. Marais (Pr. Sci. Nat) S. van Staden (Pr. Sci. Nat) Report reference: SAS 219104 Date: June 2019 Scientific Aquatic Services CC CC Reg No 2003/078943/23 Vat Reg. No. 4020235273 PO Box 751779 Gardenview 2047 Tel: 011 616 7893 Fax: 086 724 3132 E-mail: [email protected] SAS 219104 June 2019 EXECUTIVE SUMMARY Based on the findings of the freshwater ecological assessment and the results of the risk assessment it is the opinion of the ecologist that the proposed East Rand Proprietary Mines (ERPM) expansion poses a moderate risk to the integrity of the wetlands associated with the Windmill and Witpoortjie Vent Shafts. Adherence to cogent, well-conceived and ecologically sensitive site development plans, the mitigation measures provided in this report as well as general good construction practice and ongoing management, maintenance and monitoring, are essential if the significance of perceived impacts is to be reduced to limit further degradation of the freshwater environment. It is the opinion of the freshwater specialist that the proposed ERPM expansion, from a freshwater resource management perspective, is considered acceptable, with the proviso that no development takes place within the wetlands or the associated 100m GN704 Zone of Regulation and that strict adherence to mitigation measures is enforced to ensure that the ecological integrity of the freshwater environment is not further compromised. MANAGEMENT SUMMARY Scientific Aquatic Services (SAS) was appointed to conduct a freshwater ecological assessment as part of the Environmental Authorisation and Water Use Licence Application (WULA) process for the proposed East Rand Proprietary Mines (ERPM) Expansion Area 2 Mine, Gauteng Province, hereafter referred to as the ‘proposed ERPM expansion’. ERPM holds a prospecting right for the ERPM Extension 1 area, which ERPM intends to convert into a mining right and plans to consolidate the underground resources. In order to do so, this would require the development of the Windmill Shaft (a twin shaft including both access and vent shafts) and the Witpoortjie Vent Shaft (an existing ventilation shaft to be refurbished) to allow access to the underground operations. A desktop study was conducted in which watercourses were identified for on-site investigation, and relevant national and provincial databases were consulted. The results of the desktop study are contained in Section 4 of this report. In order to identify all watercourses that may potentially be impacted by the proposed ERPM expansion, a 500m “zone of investigation” around the proposed ERPM expansion, in accordance with Government Notice (GN) 509 of 2016 as it relates to the National Water Act, 1998 (Act No. 36 of 1998), was used as a guide in which to assess possible sensitivities of the receiving freshwater environment. This area – i.e. the 500m zone of investigation around the proposed ERPM expansion - will henceforth be referred to as the “investigation area”. During the site assessment undertaken on the 9th of May 2019, a single watercourse was identified within the investigation area of the Windmill Shaft, a Hillslope Seep (HSS) wetland, while a single watercourse, a Channelled Valley Bottom (CVB) wetland, was identified within the investigation area of the Witpoortjie Vent Shaft. The HSS wetland associated with the Windmill Shaft is located along the northern boundary of the investigation area and drains in a northerly direction. The CVB wetland associated with the Witpoortjie Vent Shaft is located within the eastern and southern portions of the investigation area and drains in a south westerly direction towards an unnamed tributary of the Rietspruit River. A summary of the assessment of the wetlands is provided in Table A below: Table A: Summary of results of the field assessment of the wetlands associated with the proposed ERPM expansion. Watercourse PES Ecoservices EIS REC and RMO REC: D (Largely modified) CVB wetland D (Largely modified) Intermediate Moderate RMO: Maintain C (Moderately REC: C (Moderately modified) HSS wetland Moderately low Low/marginal modified) RMO: Maintain ii SAS 219104 June 2019 Following the ecological assessment of the wetlands, the Department of Water and Sanitation (DWS) Risk Assessment Matrix (2016) as it relates to activities as stipulated in Section 21(c) and (i) of the National Water Act, 1998 (Act No. 36 of 1998) was applied to ascertain the significance of possible impacts which may occur as a result of the proposed ERPM expansion. As the delineated wetlands do not fall within the proposed Windmill or Witpoortjie Vent areas, and as it is assumed that no development will therefore take place within the wetland or the associated 100m GN704 Zone of Regulation, some activities pertaining to the proposed ERPM expansion, such as site preparation and construction of surface infrastructure, are anticipated to pose a low risk to the wetlands. However, the outcome of the Risk Assessment indicated that certain activities associated with the proposed ERPM expansion, such as the development of the shafts and clean and dirty water separation systems, will pose a moderate risk to the receiving freshwater environment during the construction phase. The results of the risk assessment are summarised in Table B below. Table B: Summary of the results of the risk assessment applied to the wetlands associated with the proposed ERPM expansion. No. Activity Aspect Impact Phase Risk Rating Significance Site preparation prior to construction activities related *Vehicular movement *Runoff with high sediment loads entering the to the proposed and access to the site; wetlands as a result of exposed soil from new Windmill *Removal of terrestrial cleared areas, smothering the wetland Shaft and the vegetation and vegetation and thus altering the habitat of the rehabilitation of associated wetlands, leading to areas within the wetlands the existing disturbances (rubble more suited to terrestrial vegetation; 1 Witpoortjie Vent and litter) to soil; and *Compaction of soil due to the movement of 52.3 L Shaft, including *Possible unplanned construction machinery leading to alterations proposed surface and uncontrolled of runoff patterns into the wetlands; infrastructure, movement of *Proliferation of alien vegetation as a result of and the construction machinery disturbances; and placement of through the CVB and *Vegetation degradation, and the subsequent contractor HSS wetland. loss of habitat for wetland species. laydown areas and storage facilities. *Movement of construction machinery within the 100m Construction Phase GN704 Zone of *Loss of wetland habitat and ecological Regulation (HSS structure as a result of edge effects associated wetland); with the ERPM expansion; Construction of *Ground-breaking and *Impacts to the ecoservice provision of the surface earthworks relating to wetland; infrastructure foundations; *Potential impacts on the hydrology and associated with *Mixing and casting of sedimentation of the wetland, leading to 2 the Windmill 54 L concrete for alteration of the flood regime; Shaft, such as construction purposes; *Potential impacts on the water quality of buildings, *Stockpiling of runoff which may potentially enter the structures and construction materials; downgradient wetland and contamination of internal roads. *Creation of a topsoil soils due to concrete being cast; and stockpile and a Waste *Proliferation of alien and invasive plant Rock Dump (WRD); species within the wetlands. *Increased likelihood of dust generation due to exposed soils; and iii SAS 219104 June 2019 No. Activity Aspect Impact Phase Risk Rating Significance *Changes to stormwater runoff in the landscape as a result of construction activities and increased impermeable surfaces. *Movement of Construction of construction machinery surface within the 100m infrastructure GN704 Zone of associated with Regulation (CVB the Witpoortjie wetland); Vent Shaft, *Stockpiling of including construction materials; refurbishment of *Increased likelihood of 45 L the existing dust generation due to ventilation shaft, exposed soils; and surface *Changes to ventilation fans, stormwater runoff in an access road the landscape as a and a generator result of construction and compressor. activities and increased impermeable surfaces. Loss of catchment yield resulting from stormwater containment, leading to: *Ground-breaking *Increased flood peaks as a result of associated with the formalisation and concentration of surface Development of excavation of trenches; runoff in clean water diversion structures; clean and dirty *Removal of topsoil; *Potential for erosion, leading to sedimentation 3 87.8 M water separation and of the wetlands; systems. *Excavation activities *Reduction in volume of water entering the leading to the wetlands, leading to loss of recharge of the stockpiling of soil. wetlands; and *Altered vegetation community structure and diversity due to moisture stress. *Potential subsidence of surrounding environment if pillars are insufficient to support the ground; *Excavation, drilling *Potential creation of a cone of depression, Sinking of the and blasting in order to