Louis Aucamp

INFRASTRUCTURE BANKABLE FEASIBILITY REPORT FOR XXXX OI BFS CHAPTER 8 – INFRASTRUCTURE OPERATIONAL CONCEPT DOCUMENT NUMBER: LPX--ENG-REP-0001 XXXX COMPILED BY: NAME Louis Aucamp TITLE SIGNATURE XXXX Senior Project Manager DATE 2015/05/18 REVIEWED BY: NAME TITLE SIGNATURE DATE Ferdi Smith XXXX Lead Engineer, Civil 2015/05/18 Willem Visagie XXXX Engineering Manager 2015/05/18 Lenro Harmse XXXX Project Manager 2015/05/18 APPROVED BY: NAME TITLE SIGNATURE DATE Shilendra Pillay OI Project, Engineering Manager 2015/05/18 Sibo Khumalo, OI Project, Project Manager 2015/05/18 Gert Fourie, OI Project, Construction Manager 2015/05/18 DOCUMENT CONTROL DOCUMENT INFORMATION INFORMATION Document Owner L Harmse Publish Date - DOCUMENT HISTORY VERSION A DATE- CHANGES Issue for Review ABBREVIATIONS AND ACRONYMS The following acronyms are applicable to this document: For more details, please consult the Glossary. ACRONYM DESCRIPTION BFS Bankable Feasibility Study CHPP Coal Handling and Preparation Plant DWA Department of Water Affairs FEL Front-end loader FEL -3 Front end loading (project implementation phase) m Metre m³ Cubic Metre SWMA Storm Water Management Area DEFINITIONS The definitions listed below apply to this document. For more details, please consult the Glossary. TERM DEFINITION TERM DEFINITION APPROVED Approved by the Engineer in writing. CLIENT Xxxx DRAWINGS Fully dimensioned drawings and schedule prepared by the Engineer, showing all members with their size, concrete grade and enforcement layout, and any other information required for construction ECSA Engineering Council of South Africa ENGINEER The individual, or company, responsible for the design, for preparation of the Drawings (or approval of Drawings prepared by others) and where applicable, inspection of construction for conformity with design. ISO International Standards Organization SANS South African National Standard REFERENCES The following documents are either Applicable Documents - applicable to the extent specified herein and thus forming part of this document. The applicability will generally relate to the Project in terms of policy, procedures, standards, qualification, etc.; or Reference Documents - where the information concerned has been fully extracted from the reference document and added to this document, or where the reference document contains information relevant to this document, or for information only. DOCUMENT NAME RELEVANCE PROJECT REFERENCE DOCUMENTS GCS Project Number: 11-447 Client Reference: 11-447 GCS, Hydrological Investigation on Xxxx Mine Report, Version – Draft 3, October 2013 EWPM- Xxxx OI BFS Project : Project Scope of Work EWPM- Xxxx OI BFS Project : Battery Limits and Interface Plan LPX--CIV-SPE-0001 Xxxx OI BFS Project : Civil Infrastructure Design Criteria LPX--STE-SPE-0001 Xxxx OI BFS Project : Civil Structural Design Criteria LPX--CIV-SPE-0001 Xxxx OI BFS Project : Civil Architectural Design Criteria LPX--ELE-SPE-0001 Xxxx OI BFS Project : Electrical and Process Control Design Criteria LEGISLATIVE REQUIREMENTS National Environmental Management Waste Act (Act No 59 of 2008) Regulation 634 of the National Environmental Waste Management Act (Act No 59 of 2008), Waste Classification and Management Regulations; Regulation 635 of the National Environmental Waste Management Act (Act No 59 of 2008), National norms and standards for the assessment of waste for landfill disposal Regulation 636 of the National Environmental Waste Management Act (Act 59 of 2008), National Norms and Standards for the disposal of waste to landfill Notice 737 of 2013 by the Department of Environmental Affairs, Explanatory Summary of the National Environmental Management: Waste Amendment Bill, 2013 Police Services Code of Practice SAP412 South African Police Specifications for electrical fencing of magazines Gazette No 26187, Revision of General Authorizations in terms of Section 39 of the National Water Act, 1998 (Act No 36 of 1998) Government Gazette, 18 May 1984 No. 9225, Regulation No 991 Requirements for the purification of waste water effluent National Water Act (Act 36 of 1998) Regulation GN704 Mine Health and Safety Act, 1996 Mineral and Petroleum Resources Development Act, 2002 (Act 28 of 2002) Section 39 (4) of the Act Hazardous Substances Act No 15 of 1973 DOCUMENT NAME RELEVANCE Environment Conservation Act No 73 of 1989 National Environment Management Act No 107 of 1998 Government Notice No. 704, National Water Act, 1998 (Act No. 36 of 1998) dealing with regulations on use of water mining and related activities aimed at the protection water resources The Dam Safety regulations (published in Government Notice R. 139 of 24 February 2012) DOCUMENT DISTRIBUTION This document is available for internal and external use only at Xxxx Resources Technology. TABLE OF CONTENTS DOCUMENT CONTROL ..........................................................................................................................2 ABBREVIATIONS AND ACRONYMS .....................................................................................................3 DEFINITIONS ...........................................................................................................................................3 REFERENCES .........................................................................................................................................4 DOCUMENT DISTRIBUTION ..................................................................................................................5 TABLE OF CONTENTS ...........................................................................................................................6 TABLE OF FIGURES ...............................................................................................................................8 TABLE OF TABLES ................................................................................................................................8 8. INFRASTRUCTURE OPERATIONAL CONCEPT ......................................................................10 8.1 AREA PLAN .......................................................................................................................10 8.2 EQUIPMENT, MOBILE, MAINTENANCE AND FIXED .....................................................10 8.3 WORKSHOPS ...................................................................................................................11 8.4 REPAIR FACILITIES .........................................................................................................12 8.5 WATER SUPPLY (DAMS, BORE HOLES, ETC.) .............................................................12 8.5.1 Design Standards..................................................................................................12 8.5.2 Potable Water Supply and Reticulation ................................................................12 8.5.3 8.5.4 8.6 8.5.2.1 Objective ..............................................................................................12 8.5.2.2 Design Criteria and Parameters ...........................................................13 8.5.2.3 System layout and description .............................................................15 Process Water Supply...........................................................................................16 8.5.3.1 Objective ..............................................................................................16 8.5.3.2 Design Criteria and Parameters ...........................................................16 8.5.3.3 System layout and description .............................................................17 Fire Water Supply .................................................................................................18 8.5.4.1 Objective ..............................................................................................18 8.5.4.2 Design Criteria and Parameters ...........................................................18 8.5.4.3 System layout and description .............................................................20 POWER SUPPLY ..............................................................................................................20 8.6.1 OI Project Main Power Supply ..............................................................................20 8.6.2 OI Project 11kV Distribution ..................................................................................21 8.6.3 OI Internal 11kV distribution ..................................................................................21 8.6.4 11kV Feed to OI Screening Plant .........................................................................23 8.6.5 Infrastructure Low Voltage Reticulation ................................................................23 8.6.6 Infrastructure Substation Design ...........................................................................24 8.7 TRANSPORT (ROAD, RAIL, AIR, PERSONNEL, LOGISTICS, ETC.) .............................24 8.8 LOAD OUT STATION (OPERATING) ...............................................................................24 8.9 Bulk Earthworks, Terraces and ROADS ............................................................................24 8.9.1 Bulk Earth works and Terraces .............................................................................24 8.9.2 8.9.1.1 Objective ..............................................................................................24 8.9.1.2 Design Criteria and Parameters ...........................................................25 8.9.1.3 Platform layout and description ............................................................28 Roads ....................................................................................................................29 8.9.2.1 Objective ..............................................................................................29 8.9.2.2 Design Criteria and Parameters ...........................................................30 8.9.2.3 Road considerations and description ...................................................34 8.10 STORM WATER DRAINAGE AND SEWERAGE DISPOSAL ..........................................36 8.10.1 Storm Water Management Plan ...........................................................................- Objective .............................................................................................- Methodology Criteria and Parameters ................................................- Layout, considerations and description ................................................38 8.10.2 Storm Water Drainage .........................................................................................- Objective .............................................................................................- Rainfall and site conditions .................................................................- Design Criteria and Parameters ..........................................................- Storm water drainage layout and description .......................................42 8.10.3 Pollution Control Dam ..........................................................................................- Objective .............................................................................................- Design Criteria and Parameters ..........................................................- Dam and silt trap layout and description ..............................................46 8.10.4 Road Storm Water Design ....................................................................................48 8.10.5 Sewerage .............................................................................................................- Objective .............................................................................................- Design Criteria and Parameters ..........................................................- Sewer layout and description ...............................................................50 8.11 COMMUNICATIONS (RADIO’S, TELEPHONE) (INTERNAL/ EXTERNAL) .....................52 8.12 OFFICES (FURNITURE, COMPUTERS, OFFICE EQUIPMENT, ETC.) ..........................52 8.13 WAREHOUSING (SPARE PARTS) ...................................................................................56 8.14 ACCOMMODATION (GUEST HOUSE, SPORTING FACILITIES, CLUB, ETC.) .............56 8.15 CHANGE HOUSES ...........................................................................................................56 8.16 LABORATORY...................................................................................................................57 8.17 SECURITY (FENCES, LIGHTS) ........................................................................................58 8.18 EXPORT FACILITY ...........................................................................................................58 8.19 TEMPORARY SERVICES .................................................................................................58 8.20 RESCUE MEDICAL FACILITIES .......................................................................................60 8.21 LANDING STRIP................................................................................................................60 8.22 WATER DISCHARGE FACILITIES ...................................................................................60 8.23 MANAGEMENT INFORMATION SYSTEMS .....................................................................60 TABLE OF FIGURES Figure 1: 1:50000 Locality Plan ............................................................................................................. 10 Figure 2 : General layout ....................................................................................................................... 11 Figure 3 : Workshop typical section ...................................................................................................... 11 Figure 4 : Water supply and potable water layout ................................................................................. 16 Figure 5 : Process water supply layout ................................................................................................. 18 Figure 6 : Fire water supply layout ........................................................................................................ 20 Figure 7 : Xxxx OI – 11kV Distribution Network .................................................................................... 21 Figure 8 : Xxxx OI – Substation Positions ............................................................................................. 22 Figure 9 : Xxxx OI – Miniature Substation Positions ............................................................................. 22 Figure 10 : Plant terrace layout and other terraces ............................................................................... 25 Figure 11 : Dynamic compaction ........................................................................................................... 26 Figure 12 : Stone columns and rockfill rafts .......................................................................................... 27 Figure 13 : General layout of roads ....................................................................................................... 29 Figure 14 : Storm water management plan procedure .......................................................................... 38 Figure 15 : Major catchment areas ........................................................................................................ 39 Figure 16 : Clean water drains .............................................................................................................. 43 Figure 17 : Dirty water drains ................................................................................................................ 44 Figure 18 : Dam storage zones ............................................................................................................. 45 Figure 19 : Pollution control dam ........................................................................................................... 46 Figure 20 : Silt trap ................................................................................................................................ 47 Figure 21 : Sewer layout ........................................................................................................................ 51 Figure 22 : General office layout ........................................................................................................... 54 Figure 23 : Control office ground floor layout ........................................................................................ 54 Figure 24 : Control office ground floor layout ........................................................................................ 56 Figure 25 : Female change house and laundry floor layout .................................................................. 57 Figure 26 : Male change house floor layout .......................................................................................... 57 Figure 27 : Contractor’s laydown area .................................................................................................. 59 TABLE OF TABLES Table 1 : Minimum design criteria for pipelines ..................................................................................... 13 Table 2 : Calculations of average daily demand for water and sewer .................................................. 13 Table 3 : Minimum design standards for potable water ........................................................................ 14 Table 4 : Process water minimum design criteria ................................................................................. 17 Table 5 : Minimum design criteria and parameters for fire water .......................................................... 18 Table 6 : Dynamic compaction platforms, area, depth and bearing capacity ....................................... 26 Table 7 : Wearing course material specification.................................................................................... 28 Table 8 : Design criteria for the access road to the new OI plant site ................................................... 30 Table 9 : Design criteria for the roads on the platforms and terraces ................................................... 32 Table 10 : Design criteria for conveyor maintenance roads .................................................................. 33 Table 11 : Design criteria for mine haul roads....................................................................................... 34 Table 12 : Design rainfall depths ........................................................................................................... 40 Table 13 : Soil parameters .................................................................................................................... 41 Table 14 : Catchment parameters ......................................................................................................... 41 Table 15 : Storm water design criteria and parameters ........................................................................ 42 Table 16 : Clean water area storm water system .................................................................................. 42 Table 17 : Dirty water area storm water system .................................................................................... 44 Table 18 : Design criteria for storm water management on the roads .................................................. 48 Table 19 : Minimum design criteria for sewer systems ......................................................................... 49 Table 20: Sewer system description ..................................................................................................... 50 8. INFRASTRUCTURE OPERATIONAL CONCEPT 8.1 AREA PLAN The Xxxx OI Project is an expansion project that falls within the current mining rights area of the existing Xxxx Colliery. Figure 1: 1:50000 Locality Plan Xxxx Consulting Engineers have been appointed to do a bankable feasibility study for the development of the project infrastructure. Total work includes the feasibility design of all plant and conveyor terraces, haul roads, plant roads and all storm water measures to drain the plant site and surrounding areas in compliance with the Water Act and Environmental Legislation. It also includes the provision of relevant services for the project such as potable water, process water, fire water, sewers and electricity. All designs were formulated to suit the requirements of Xxxx for the Xxxx Mine. The design criteria as documented in the Infrastructure Design Criteria Report formed the basis of the designs. The design implementation is presented in the Infrastructure Design Report. 8.2 EQUIPMENT, MOBILE, MAINTENANCE AND FIXED Xxxx was not responsible for the selection of mobile and maintenance equipment. All equipment will be selected by Xxxx. 8.3 WORKSHOPS A new plant workshop to cater for the needs of the Xxxx OI project will be constructed as shown on the general platform layout as presented in Figure 2. Figure 2 : General layout The workshop has been designed as a steel framed building with cladding and a concrete floor and foundations, all to the relevant design codes and loadings. The workshop is 42 m by 21 m by 14 m high (925 m2). To lift heavy parts an overhead Class 2 crane of 5 ton capacity is included in the workshop. Figure 3 show a typical section through the workshop. Figure 3 : Workshop typical section 8.4 REPAIR FACILITIES No repair facilities has been included in the infrastructure scope. 8.5 WATER SUPPLY (DAMS, BORE HOLES, ETC.) 8.5.1 DESIGN STANDARDS The design of the potable water supply and reticulation system was done in accordance with the Civil Infrastructure Design Criteria (refer to Document No: LPX--civ-spe-0001). These criteria includes the following specifications:  SANS 0252: Water Supply and Drainage for Buildings  SANS 10400: The Application of the National Building Regulations  Guidelines for Human Settlement: Planning and Design 8.5.2 POTABLE WATER SUPPLY AND RETICULATION 8.5.2.1 Objective The source of potable water for the OI project on Xxxx mine will be the existing boreholes, Witklip boreholes and Maggie’s Boreholes. The existing Xxxx operation receives its potable supply exclusively from the Witklip borehole with Maggie’s borehole supplying only the training center. The current water tank will be removed as part of the mine rehabilitation and a new water tank and potable water reticulation to supply the existing and the Xxxx OI requirements will be installed. Design Criteria and Parameters The reticulation network and water supply lines will be HDPE PE100 pipes to SANS 4427. The criteria and parameters used in the design of the potable water supply is presented in the following tables: Table 1 : Minimum design criteria for pipelines Description Value Fluid Clean water Water demand (max) See Table 11 Water density 1000 kg/m³ Gravitational acceleration 9.81 m/s² Water Kinematic Viscosity 1.14 x 10-6 m²/s Minimum linear velocity 0.7 m/s Design flow velocity 1.0 m/s to 1.8 m/s Maximum flow velocity Minimum pipe class 2.5 m/s HDPe (above or below ground) uPVC (below ground) According to SANS requirements Minimum depth of cover to buried pipes HDPE Temperature – Pressure derating factors Pipe supports 1m in open terrain Must be applied to HDPE pipes when operating temperatures rise above 20°C Reinforced concrete plinths Test pressure 1,5 x the pipe class AVK, VOSA (or similar approved) flanged, rising spindle, one man manual operated, resilient seal, epoxy coated, PN16 Steel PN 16, flanged according to table 1600/10 (SANS 1123), Hot Dipped Galvanized Vent-O-Mat RBX series, flanged Piping Material Gate valves Fittings: T-piece and Bends Air valves Table 2 : Calculations of average daily demand for water and sewer Building Type Type Criteria 8.5.2.2 PERSONS Ablution Blocks and Offices New Facility Number of Shifts/24 Hours = Existing Mine People = 285 715 SANS 10252-2:1993 T9 SANS 10252-2:1993 + 20% Reference Average Daily Demand for Potable Water = Description l/day Qty Daily Flow / Worker 20% Average Water Demand = l/pers/day Total 84 000 M3/day SANS 10252-2:1993 + 84 l/day l/s 84 Table 3 : Minimum design standards for potable water SOURCE A ground level water buffer reservoir, which is filled with water from the raw water supply pipeline. The minimum available water capacity shall be 48h of the annual average daily demand. PURIFICATION Raw water from the ground level water buffer reservoir shall be treated, if required, to ensure fitness for human consumption. (See purification plant specifications below) ELEVATED STORAGE Potable water shall be stored in a 15m high elevated reservoir, if required, to provide a constant pressurized potable feed to various draw off points. The nominal capacity of this reservoir shall be 4h of instantaneous peak demand. FLOW Personnel Water demand No of people Usage Residual Pressure To comply with the latest human resources organogram 84 Litre/person/day (SANS 10252-2: 1993) 15 m Minimum (SANS10252-2: 1993) PIPES Pipes Type Class Flow velocity in pipeline Min size - Reticulation - Connection Above ground installation for all pipe diameters, Below ground for smaller than 110 mm  pipes:, Below ground installation for pipes larger than 110 mm pipes: Minimum Pressure class Maximum Depth Pipe bedding 63 mm  25 mm  HDPE PE100 PN16 to SANS 4427 uPVC Class 16 to SABS 966: 1998 Part 1 12 1,2 m/s 1m As per SANS 1200 LB Class B Resilient Seal Gate valve to SABS 664 RSV VALVES Type Closing Pressure Anti-clockwise Rated working pressure 16 Bar PURIFICATION PLANT Description Daily Design Operating Hours Detail of purification 8.5.2.3 Containerized Potable Water Purification Plant 18h For compliance refer to SANS 241:2011 Part 1 and Part II for maximum limits for class 1 water (potable). The system design shall be based on water quality tests conducted by the Xxxx appointed Laboratory System layout and description A new tank of 136m3 capacity will be elevated on a 15m steel structure. Water from the Witklip borehole will be pumped via an extension to the existing pipeline to the new OI site into a 522m3 fire water tank situated on the ground level. A potable water buffer capacity of 22m3 is supplied in this tank and it is pumped via a separate pump set into the elevated tank mentioned above. A small automated chlorine dosing unit will dose a ready mixed water and chlorine dilution into the line directly after the potable water lift pumps to ensure that water inside the elevated tank remains bacteria free. The water supply layout is presented in Figure 4 below: Figure 4 : Water supply and potable water layout 8.5.3 PROCESS WATER SUPPLY 8.5.3.1 Objective The process water supply will feed the new raw water buffer tank from the existing return water dams and the return water pipeline will return water from the new pollution control dam to the existing return water dams. 8.5.3.2 Design Criteria and Parameters The minimum design criteria and parameters for the process water system is presented in Table 4 below: Table 4 : Process water minimum design criteria Flow Water demand Flow Pipes To be determined in association with Plant Package Consultant. Minimum size 50 mm  Above ground installation for all pipe diameters, Below ground for smaller than 110 mm  Type Pipes pipes larger than 110 mm pipes: uPVC Class 16 to SABS 966: 1998 Part 1 Class Minimum Pressure class 12 Flow velocity in pipeline Maximum 1,2 m/s Depth Pipe bedding Type Valve SANS 4427 pipes:, Below ground installation for 1m As per SANS 1200 LB Resilient Seal Gate valve to SABS 664 to fit HDPe pipes Closing Pressure 8.5.3.3 HDPe PE100 PN16 to Class B RSV Anti-clockwise Rated working pressure 16 ar System layout and description Process water will continue to be provided from the existing raw water dam. (Silwer Dam) The water is pumped via the process water supply main to the raw water buffer tank on the plant terrace. From there it is pumped directly into the DRA plant system for distribution to the various plant facilities. Water from the plant which accumulate in the Pollution Control Dam (PCD) together with any storm water runoff accumulating in the PCD is pumped back to the RWD via the return water pump main. The process water layout is presented below in Figure 5 Figure 5 : Process water supply layout 8.5.4 FIRE WATER SUPPLY 8.5.4.1 Objective The OI fire water system is designed to minimize the risk of fire damage to the process plant and supporting infrastructure. The main elements of the Xxxx OI fire water system is the following:  A ground level reservoir (522m²)  A fire pump station  A fire water reticulation system 8.5.4.2 Design Criteria and Parameters The minimum design criteria and parameters for the fire water system is presented in Table 5 below: Table 5 : Minimum design criteria and parameters for fire water LOCAL STORAGE RESERVOIR A fire water reservoir, if required, shall have a storage capacity to supply fire water for a defined period of time under full demand. The tank capacity and operating philosophy shall be based on the Fire Protection Plan which will be developed during the design process. PUMP STATION As per Fire Pump Station criteria below, if required. FIRE RISK CATEGORY A fire risk assessment shall be done. FLOW Fire hydrant Maximum flow 20 ℓ/s Nozzle controlled fire hose Maximum flow 8.3 ℓ/s Fire hose reel Maximum flow 0.5 ℓ/s Maximum head at discharge 850kPa Minimum head at discharge 300kPa Pressure No. of hydrants in operation simultaneously 3 PIPES Pipes Type Min size - Reticulation - Connection Above ground installation for all pipe diameters Below ground for smaller than 110 mm  pipes:, Below ground installation for pipes larger than 110 mm pipes: 63 mm  25 mm  Hot dipped galvanized (HDG) steel pipes HDPe PE100 PN16 to SANS 4427 uPVC Class 16 to SABS 966: 1998 Part 1 Class Minimum Pressure class 16 Flow velocity in pipeline Maximum 3 m/s Depth Pipe bedding 1m Bedding as per SANS 1200 LB Class B Type Resilient Seal Gate valve to SABS 664 RSV Closing Anti-clockwise Pressure Rated working pressure Type 65 mm Woodlands tamperproof aluminium alloy double lug instantaneous connection conforming to the requirements of SABS 1128 Parts 1 & 2 VALVES 16 Bar Hydrants Spacing 90 m FIRE WATER PUMP STATION Description Containerized Fire Pump Station Capability 75% of the maximum demand of 3 600 l/min (3 fire hydrants @ 1 200 l/min each) at 300 kPa static pressure sustainable for 120 minutes. Running Time Details 120 Minutes Diesel driven pump set with free standing fuel tank, batteries and cables Battery charger; Jockey pump set; Wall mounted control panel to ASIB specifications; Electric driven pump set. All the above built in to a container with suction and discharge manifolds including valves. 8.5.4.3 System layout and description The fire water is untreated borehole water which can be classified as potable according to SANS 241. The ground water reservoir is fed by means of a pump feed from the existing Xxxx Witklip borehole, where the dedicated fire water capacity in the tank totals 500m³ which ensures a 90min backup water capacity at a worst case system flow of 5200l/min. The fire water pump station is containerized and consist of a main electrical pump, a diesel driven pump that is equal in performance and size to the electrical pump which serves as a backup in the event of power failures and an electrical jockey pump which maintains pressure in the system under minimal flow conditions. The pump system feeds into the reticulation system, which distributes water to fire hose reels, fire hydrants and various take off points into the Xxxx OI ore processing plant. For further information on the fire protection system and criteria refer to document LPX--SHE-PLN-0001. The fire water layout is presented below in Figure 6. Figure 6 : Fire water supply layout 8.6 POWER SUPPLY 8.6.1 OI PROJECT MAIN POWER SUPPLY Xxxx Mine receives its power from ESKOM via a 132kV line feeding the Witklip Main intake substation. The incoming lines and transformers are currently only utilizing 50% of the available 20MVA which means that there is ample capacity in terms of electrical infrastructure to supply the estimated 5MVA needed for OI. The Notified maximum demand of the Xxxx Mine connection will have to be amended if the project was to go into execution. Power factor correction or (PFC) is currently done on 11kV at the Witklip 11kV substation. The current PFC banks has recently been upgraded on the mine and provision has been made in terms of a spare bay and feeder breaker to expand the PFC system for future use. It was there for decided not to do a PFC design as part of the OI electrical design and that the entire Xxxx system will be evaluated 6 months after commissioning of the OI plant to determine if further PFC banks are required since existing loads can go offline in this period. 8.6.2 OI PROJECT 11KV DISTRIBUTION The 11kV Witklip substation has a spare 800A, 11kV Feeder that will be allocated to feed the OI Project. The 11kV will be transmitted to the OI Main 11kV substation via overhead line. The line feeding OI was sized to handle close to double the estimated required load to ensure that there is capacity in the power backbone to support any future expansions. The line extends past the main plant area along the overland conveyor and terminates at the Screening Plant substation. See Figure 7 for a layout of the main 11kV distribution network. Figure 7 : Xxxx OI – 11kV Distribution Network 8.6.3 OI INTERNAL 11KV DISTRIBUTION The 11kV reticulation within the OI Project Plant and Infrastructure Area is done from the Main 11kV Substation situated to the left of the DMS plant. The plant has three major load centers which are Plant & Discard Services, ROM (Primary and Secondary crushing) and Screening. Each of these areas have a substation which services its power needs. Two of the plant substations is situated in the main plant area namely the Plant & Discard Services Substation and The ROM (Run of Mine) Substation, the Screening Substation is situated at the end of the overland conveyor and will be discussed in the next section. See Figure 8 for the substation positions. An 11kV radial feed topology was adapted for the plant process related loads. Each of the 1600kVA, 11kV/400V transformers, two at Plant & Discard Services Substation and one at the ROM Substation, is fed from an 800A 11kV feeder from the substation via underground 11kV cables in trenches along dedicated servitudes. The radial feed was preferred as supposed to a ring feed for the process feed since it reduces the requirement of MV switchgear at all the substations and in doing so reduces the substation size. Transformer selection was standardised on 1600kVA to ensure that there will be interchangeability with a single spare unit. Figure 8 : Xxxx OI – Substation Positions For all non-production related loads such as sewerage systems, area lighting, buildings and offices, fire water systems and potable water systems an 11kV Ring feed was designed feeding five strategically placed 500kVA 11kV/400V miniature substations. Each of the miniature substations was placed as close as possible to relevant load centers to reduce the cable length of low voltage distribution cables. The advantage of keeping the auxiliary systems on a separate 11kV circuit is having small power and lighting whilst the plant loads can be isolated and locked out. The ring topology, in this case, provides a capital saving on the reduction in length of 11kV cable and provides redundancy should there be a failure on one of the miniature substations or interlinking cables. See Figure 9 below for the positions of all the miniature substations indicated on the block plan. It is important to note that the 11kV feed is configured as a spur from MSS03 which has an IDDI configuration. This was done since the distance to and from MSS05 is very long and to complete the ring back to MSS04 would have required a great length of cable as well as an 11kV cable joint. Figure 9 : Xxxx OI – Miniature Substation Positions 8.6.4 11KV FEED TO OI SCREENING PLANT The third section of the Xxxx OI 11kV reticulation is the 11kV from the cable T-off point to the Screening Plant Substation along the overland product conveyor. Refer to figures 2 and 5. After the cable take-off feeding the plant area the overhead line continues as a HARE conductor since the load at the Screening Plant is small compared to the DMS plant area. The HARE conductor will provide sufficient spare capacity as well as low voltage drop and line losses. The Screening Plant substation has both an MV and LV Section. The MV section contains a four panel board which radially feeds the plant 1600kVA 11kV/400V transformer and the 500kVA 11kV/400V miniature substation. These units are matched in size and type to the transformers used in the Plant area to allow for spares to be usable throughout the OI plant. 8.6.5 INFRASTRUCTURE LOW VOLTAGE RETICULATION The electrical designs for the following low voltage loads was conducted as part of the infrastructure electrical design scope: • Raw Water Supply Pump station • Process Water, Fire Water and Potable Water Pump stations • PCD Return Pump station • Sewerage Booster station and Bio-filter Return station • Buildings and Offices • Area Lighting See drawings LPN-XXXX-EL- and LPN-XXXX-EL- for the infrastructure overall low voltage single line diagrams. See Schedule LPN-XXXXEL- for the Infrastructure Load List and Schedule LPN-XXXX-EL- for the Infrastructure Low Voltage Cable Schedule. For further information on the LV (low voltage design) please refer to the OI Infrastructure Electrical Design Report LPX--ELE-REP- INFRASTRUCTURE SUBSTATION DESIGN The Xxxx OI project electrical design required the design of four substation buildings to facilitate the electrical reticulation. These buildings are the Main 11kV Substation, Plant & Discard Services Substation, ROM substation and the Screening Plant Substation. A trade-off study between two substation construction methods, brick or pre-fabricated steel, was conducted and a recommendation was made to utilize the off-site manufactured steel option. This recommendation was based on the mitigation by this method of construction of project program risks which exist due to poor geotechnical ground conditions at Xxxx. This recommendation was rejected by the owner’s team of Xxxx mine and the decision was made to use the traditional brick and mortar construction method. Refer to Report LPX--CIVREP-0001. Please refer to the OI Infrastructure Electrical Design Report LPX--ELE-REP-0001 for more information regarding the substation designs. 8.7 TRANSPORT (ROAD, RAIL, AIR, PERSONNEL, LOGISTICS, ETC.) No transport matters has been included in the infrastructure scope. 8.8 LOAD OUT STATION (OPERATING) The load out station has not been included in the infrastructure scope. 8.9 BULK EARTHWORKS, TERRACES AND ROADS 8.9.1 BULK EARTH WORKS AND TERRACES 8.9.1.1 Objective The bulk earthworks consists of the following platform terraces: (a) The plant/structural areas consisting of: ① the primary crusher ② the secondary crusher and screening plant ③ the storage silo ④ the DMS plant ⑤ the thickeners and flock plant & various other structures (b) The workshop and office terrace (c) The overland conveyor link to the screen house (d) The conveyor link to the discard bin (e) The tip ramp and terrace The plant terrace layout and the other terraces are presented below in Figure 10. Figure 10 : Plant terrace layout and other terraces 8.9.1.2 Design Criteria and Parameters The OI Project Plant Platform is sited in an old pit area that has recently been rehabilitated and is surrounded on all sides by existing haul roads some of which have limited use. The general nature of the rehabilitated pit area comprises backfill from the spoiled mine waste material up to 40m deep. The upper 5m of material comprises low constancies which are not suitable for foundations of heavy or light infrastructure. The plant area terrace comprises a single platform for the crusher, secondary crusher and screen, storage silo, DMS plant, thickeners and various other structures. The general design and initial preparation comprises clearing, excavating to the specified depths and compacting the road bed to 600 mm depth by 12 passes of an impact roller. Due to the different loadings and requirements of the buildings and structures, the platform are divided into three areas with different foundation preparation methods. (a) The general platform: Backfill to the layer works with G9 material and construct four layers of G7 to G9 material. (b) Dynamic compactions: The areas under the buildings presented in Table 6 and Figure 8 will receive dynamic compaction by means of a free falling weight from a height of 10 to 40 meters. After the compaction the area is backfilled to the surface with layers of G5 material. Table 6 : Dynamic compaction platforms, area, depth and bearing capacity DYNAMIC COMPACTION AREA INFLUENCE DEPTH BEARING CAPACITY DESCRIPTION (M2) REQUIRED (M) ①TIP PLATFORM 7768 4 150 ②ROM SUBSTATION 414 4 100 637 4 100 ④MAGNETITE PIT 663 6 200 ⑤ WORKSHOP AREA 4178 6 200 ⑥ PLANT SUBSTATION 1019 4 100 ⑦ WATER TANK AREA 955 6 150 ⑧ SCREEN HOUSE 1560 6 200 ⑨ PC DAM 5844 6 100 TOTAL AREA 23038 - - ③CONTROL ROOM / REQUIRED KPA OFFICE Figure 11 : Dynamic compaction (c) Stone columns and a rockfill raft: The stone columns are constructed by drilling or auguring into the prepared roadbed of the platform to a depth of approximately 12 meters. Rockfill is tipped and compacted into the auger holes with dynamic compaction by means of a free falling steel weight. A Geogrid geotextile is laid on the dynamically compacted insitu soil and a rockfill raft 3000mm thick of dump rock of maximum size 300mm is constructed on top. The layer work is completed with a high strength geo-synthetic material and the construction of four layers of G7 to G5 material. The areas that will receive stone columns and rockfill rafts are presented in Figure 9 below: Figure 12 : Stone columns and rockfill rafts The workshop and office terrace receive the same treatment as the dynamic compaction option for the plant terrace. The overland conveyor terraces are constructed by clearing the area, compacting the insitu roadbed and laying a geotextile on top. Bulk fill layers of G9 material are constructed to the underside of the layer works. The layer works consists of three layers of G7 to G5 material. The tip terrace area is cleared and compacted by dynamic compaction as for the plant terrace. The insitu roadbed is compacted and bulk fill of G9 material is constructed and compacted by 12 passes of an impact roller to the underside of the layer works. Three layers of compacted G7 to G4 material is constructed with a wearing course on top that conform to the specification in Table 7. Table 7 : Wearing course material specification WEARING COURSE MATERIAL SPECIFICATION MATERIAL PARAMETER Minimum Maximum Shrinkage Product 85 200 Grading Coefficient 20 35 Dust Ratio 0.4 0.6 Liquid Limit (%) 17 24 Plastic Limit (%) 12 17 Plasticity Index 4 8 CBR at 98% Mod AASHTO 80 - - 40 Maximum Particle (mm) 8.9.1.3 RANGE Platform layout and description The plant area terrace comprises a single platform for the crusher, secondary crusher and screen, storage silo, DMS plant, thickeners and various other structures. The platform is shaped to a low point on the northern side of the platform adjacent to the discard bin conveyor link so as to drain to the silt trap and PCD also in that area. The platform slopes with a minimum fall of 1%. The general layout has been fixed to suit the grading of the haul road and tip ramp which is in turn governed by the levels of the existing haul road access to the pit. This has resulted in cut on the north-eastern side of the platform and fill on the western side. This provides the optimal balance between the constraints of the maximum haul road grades and an evenly sided platform. The workshop and office platform is actually incorporated with the plant terrace but is sloped in a north-westerly direction to a low point on the western edge where the two platforms meet. It also slopes at a minimum slope of 1%. The main access road connects to the south-eastern corner of the platform. The discard bin conveyor platform connects the plant terrace to the discard bin on the haul road. It is a narrow platform for the conveyor and its service road. The PCD has been situated in the triangle shaped area between the conveyor and the haul road tip ramp, because it must drain both the haul road and the plant terrace. The screen house overland conveyor platform links the plant terrace to the screen house and incorporates a service road. It crosses under two haul roads through culverts. The platform has a 2% cross fall to the upstream (northeast) side and drains into toe drains. 8.9.2 ROADS 8.9.2.1 Objective The following roads form part of the infrastructure scope:         The haul road and tip ramp The haul road crossing (Conveyor South) The haul road crossing (Conveyor North) The link roads from the haul roads to the conveyor The screen house access road The access road to the plant The magazine access road The internal platform roads The general layout of the roads are presented in Figure 13. Figure 13 : General layout of roads 8.9.2.2 Design Criteria and Parameters The roads have been designed to suite the requirements of Xxxx and the conditions pertaining at their Xxxx mine. The Infrastructure Design Criteria forms the basis if the road design. All assumptions made in the design are included in this document. The road design criteria are presented in Tables 8, 9, 10 and 11 below. Table 8 : Design criteria for the access road to the new OI plant site DESCRIPTION VALUE Design vehicle: Geometry WB-20 Truck Design vehicle axle 8t maximum Design :life of roads Lane width 30 years Determine traffic volume in association with Xxxx and Plant Package Consultant 2 lanes @ 3,7m each Geometric design speed 60 km/h Min stopping sight distance 80 m (TMH 17) Minimum bellmouth radii 15 m (TMH 17) Minimum horizontal curve radius 110 m (TMH 17) Minimum longitudinal gradient 1.0% Maximum longitudinal gradient 6% for flat topography (TMH 17) Minimum cross fall 2% Max super-elevation 4% - 6% Minimum vertical curve length Min K Factor  Crest  Sag Layer works 100m (TMH 17) Traffic count 16 (TMH 17) 16 (TMH 17)  Shoulder Asphalt Minimum 1:2 when in cut Minimum 1:2 when in fill 1m wide Side safety berm None Surfacing Side slope Table 9 : Design criteria for the roads on the platforms and terraces DESCRIPTION VALUE Design vehicle: Geometry WB-20 Truck Design vehicle axle 8t maximum Design life of roads Lane width 20 years Determine traffic volume in association with Xxxx and Plant Package Consultant 2 lanes @ 3,0m each Geometric design speed 40 km/h Min stopping sight distance 50 m (TMH 17) Minimum turning radius 15 m (TMH 17) Minimum horizontal curve radius 80m (TMH 17) Minimum longitudinal gradient 1.0% Maximum longitudinal gradient 6% (TMH 17) Minimum cross fall 2% Max super-elevation 4% - 6% Minimum vertical curve length Min K Factor  Crest  Sag Layer works 60 m (TMH 17) Traffic count  Surfacing Side slope Shoulder 6 (TMH 17) 8 (TMH 17) Dust treated wearing course Minimum 1:2 when in cut Minimum 1:2 when in fill 1 m wide Table 10 : Design criteria for conveyor maintenance roads DESCRIPTION VALUE Design vehicle: Geometry SU-9 Truck Design vehicle axle 8t maximum Design life of roads Lane width 20 years Determine traffic volume in association with Xxxx and Plant Package Consultant 1 lane @ 3,0 m Geometric design speed 40 km/h Min stopping sight distance 50 m (TMH 17) Minimum turning radius 15 m (TMH 17) Minimum horizontal curve radius 80 m (TMH 17) Minimum longitudinal gradient 1.0% Maximum longitudinal gradient 6% (TMH 17) Minimum cross fall 2% Max super-elevation 4% - 6% Minimum vertical curve length Min K Factor  Crest  Sag Layer works 60 m (TMH 17) Traffic count  Surfacing Side slope Shoulder 6 (TMH 17) 8 (TMH 17) Gravel Minimum 1:2 when in cut Minimum 1:2 when in fill 1 m wide Table 11 : Design criteria for mine haul roads DESCRIPTION VALUE Design vehicle CAT 777F Coal Truck, Off-Highway Truck Design truck dimensions Length – 11,140 m Width – 6,404 m Height – 5,840 m Height – / m with bin in upright position : 10,319 m Design unladen vehicle weight Front – 32,3 t Rear – 37,9 t Total empty vehicle weight – 70,2 t Design laden vehicle weight Front – 54,3 t Rear – 110,3 t Total laden vehicle weight – 164,6 t Minimum turning circle clearance diameter Minimum design turning circle diameter Maximum steer angle 28,4 m 30 m 30,5 ° Design life of roads 20 years Traffic count TBC Lane width 2 lanes @ 12.5 m each (excluding safety berms) Geometric design speed 40 km/hr Min stopping sight distance 150 m Minimum horizontal curve radius 250 m @ 40 km/hr with 4% super-elevation Minimum longitudinal gradient 1.0 % Maximum longitudinal gradient 8% Minimum cross fall 3% Max super-elevation Maximum 4% Minimum vertical curve length 140 m @ 40 km/hr for a difference in grades of 8% Layer works  Surfacing Dust treated gravel Shoulder No shoulder Uncompacted earth berm Height = 0,75 x tire diameter Side slopes = 1:1.5 Compacted earth berm Height = 0,75 x tire diameter Side slopes = 1:1.5 Center/ Collision safety berm Side safety berm 8.9.2.3 Road considerations and description Geometric elements of all and especially haul roads should be designed to provide safe, efficient travel at normal operating speeds. Horizontal and vertical alignments are designed with attention to the key road design parameters, namely grade, traffic layout, curves, intersections and switchbacks. As the horizontal and vertical alignments are important to prevent accidents, close attention was paid to sight and stopping distances. The general nature of the rehabilitated pit area comprises backfill from the spoiled mine waste material up to 40m deep. The upper 5m of material comprises low constancies which are not suitable for foundations of roads. In general the natural materials found on site are not suitable for use in the construction of the roads. The overburden from the pit excavation can be selected to get a G9 material and a bank of sandstone that has been found also from current pit excavations is being stockpiled for use on the OI project. With weathering and mechanical modification this material will provide a G6 material which can be used for selected fill and selected layer works. All other specified road materials will have to be imported from commercial sources. In general the road layers will consist of the following layer works:  A wearing course layer conforming to the parameters specified in Table 7.  Three compacted layers consisting of G7 to G4 material.  Bulk fill of G9 material  The insitu roadbed compacted by 12 passes of an impact roller The haul road and tip ramp provides access from a point on the existing pit access haul road to the tip terrace adjacent to the plant platform and the primary crusher. This road has a flat section two thirds of the way from the tip terrace where a slip road has been provided on the descending carriage way of the tip ramp where the discard bin has been sited. This section is close to the NGL of the site. The tip ramp rises up to an eight meters deep fill at the tip terrace. The discard bin section has been kept at a slope of 2% for safe stopping and loading of the truck. A short steep section of road in cut connects to the existing haul road. The ground level overland conveyor crosses two of the haul roads one to the north and one to the south. A large culvert will be constructed over the road to house the conveyor and then a ramp will be built over the culvert. Due to the consolidated nature of the existing haul roads no roadbed preparation needs to be carried out. The same layer works as for the new haul roads will be implemented. The roadbed for the link roads will be constructed with 12 passes of the impact roller. The fill will then be constructed to the underside of the layer works. The layer works will comprise one compacted layer and a wearing course. The access road to the plant links the existing workshop area to the new plant platform. The first part of road falls on an existing temporary access road and a fill platform for a temporary truck dispatch office. This section can have a conventional roadbed preparation. The second portion of the road crosses a corner of an old existing discard paddock an existing haul road and a section of rehabilitated pit area. This section will require a roadbed, fill and the layer works the same as for the link roads. The screen house access road is a deviation of an existing road which has to be moved to make room for the overland conveyor to tie into the screen house as well as for the shifted road to tie back into the existing stockpile road. The roadbed, fill and the layer works will be the same as for the link roads. Due to the fact that the old haul road which gave access to the new magazine facility has been cut in two by the new haul road a link between the pit access haul road and the eastern section of the old road has been provided. This road crosses an area of rehabilitated pit fill and thus requires a roadbed, fill and layer works the same as for the link roads. The layer works and wearing course for the roads on the platform are incorporated in the platform design and no further considerations are required. The design of storm water is dealt with in Section 8.10 and the management of the storm water on the roads will be included in that section. 8.10 STORM WATER DRAINAGE AND SEWERAGE DISPOSAL 8.10.1 STORM WATER MANAGEMENT PLAN 8.10.1.1 Objective The storm water management plan has been undertaken to ensure that Xxxx understands the costs and time lines of the storm water portion of the project in order to make an investment decision. The SWMP only looks at the OI Project infrastructure and links it to the existing storm water management plan principles already in operation at Xxxx Mine. The main water and management objectives that are considered to be relevant to the design and planning of the storm water drainage system will include:  Minimizing the risk of flooding  Minimizing inconvenience caused by frequent storms  Protecting the mine personnel and preventing the loss of life due to severe storm and/or malfunctioning drainage systems.  Preventing erosion and siltation  Protection of receiving water bodies  Minimizing costs  Sustainability of storm water management systems  Environmental and water pollution considerations  Confine any unpolluted water to a clean water system  Design a clean water system that it is not likely to overspill into any dirty water system more than once in 50 years.  Design all water systems, including residue deposits, in any area so as to prevent the pollution of any clean water resource  Prevent polluted water from entering any clean water source, either by natural flow or by seepage.   Design a dirty water system that is not likely to overspill into any clean water system more than once in 50 years. Run-off simulations to be conducted with a suitable hydrological modeling software package in order to ensure that the entire system can be dynamically analyzed. 8.10.1.2 Methodology Criteria and Parameters The Department of Water Affairs Best Practice Guidelines for water resource protection in the South African mining industry have been used in the compilation of this SWMP, in particular G1: Storm water Management. The procedure adopted is that outlined in chapter 4 of the guideline and the abbreviated flowchart shown here below in Figure 14. Please refer to the document “LPX--CIV-PLN-0001 Storm water management plan” that describe all the requirements to comply with the legal and regulatory aspects of the SWMP. The Section references contained in Figure 14 refer to the relevant sections in the SWMP referenced above. Figure 14 : Storm water management plan procedure Define Objectives of Stormwater Management Plan Section 4 Technical Situation Analysis and Evaluation Section 5 Conceptual Design and Review Section 6 Existing Mine or new operations Existing Mine Existing Management Plan New Operation Define Infrastructure Required Section 7 Legislative Aspects Section 8 and Define Operational, Management & Monitoring Systems & Responsibilities Section 9, 10, 11, 12 & 13 Document the SWMP Section 14 Follow Up Procedure Undertake Final Detailed Design of all Required Infrastructure Implement, Manage and Monitor SWMP and Systems Formally Review SWMP at Regular Intervals 8.10.1.3 Layout, considerations and description The new OI pit area of the mine will be managed under the current operating philosophies of the dirty water system of the mine i.e., an average 70% will be allowed to evaporate, 20% will be stored in the pit and 10% will be pumped back to the Return Water Dam (RWD). Clean water outside of the pit will be prevented from entering the pit by means of constructing a berm along the edge of the open pit. The major catchment areas are as shown in Figure 15 below: Figure 15 : Major catchment areas The plant area is divided into clean and dirty water areas. The plant terrace is situated in the center of a rehabilitated area between old and new haul roads. The pit terrace, haul road, tip ramp and tip comprise the dirty water area (Shaded pink on the plan) these areas are drained via concrete lined dirty water drains (DWDs) to a pollution control dam (PCD) sited between the tip ramp, the plant terrace and the discard bin conveyor. The workshop and office terrace and the conveyor terrace comprise the clean water area (shaded orange on the plan) and drain via a series of unlined clean water drains (CWDs) into the surrounding clean water areas (shaded green on the plan). Several natural ponding areas have been left after the rehabilitation process (shaded yellow on the plan).This feature has been incorporated into the storm water design as it reduces the size of infrastructure required and maintains the wetlands nature of the original site. The ponds operate on two levels, the status quo level where water has no outlet so remains there until it evaporates, and the attenuation level where the depth increases with the larger storms, but eventually drains away via the smaller pipes of the storm water infrastructure. The three ponds to the south of the plant terrace will not be incorporated in this way and will be filled up and graded to drain freely away from the terrace so as not to affect the groundwater levels under the terrace itself. The upstream storm water eventually drains away through the pipe culvert under the conveyor terrace into a natural low lying area of SWMA 4 of the current clean water system of the mine. The clean water to drain to the east of the tip ramp and the overflow from the pollution control dam (PCD) both drain in a northerly direction and outlet into the adjacent catchment which flows down the existing haul road that gives access to the pit. The storm water drainage and the pollution control dam and measures are presented in Sections 8.10.2 and 8.10.3 below. 8.10.2 STORM WATER DRAINAGE 8.10.2.1 Objective The storm water drainage forms an integral part of the project. The catchment areas must be classified in terms of the “National Water Act, 1998 (Act no.36 of 1998)” and Regulation GN704 under the water act as regulations on the use of water for mining and related activities aimed at the protection of water resources. The National Environmental Waste Act (Act № 59 of 2008) must also be addressed specifically in relation to the civil works with regard to the IWULA. To comply with the regulatory requirements the following philosophy is adopted;   Separate the storm water catchments into clean and polluted water areas. Quantify the flow for each area and design a storm water system for the 1:50 year storm runoff. 8.10.2.2 Rainfall and site conditions The block OI plant area and initial pit area fall within the boundary of the current Xxxx mining area. The site slopes in a northwesterly direction at an average slope of 1.6%. The plant will be sited on open land northeast of the existing mine infrastructure and which comprises old pit areas recently rehabilitated. The rainfall runoffs and volumes to be contained as required by legislation, (Government Notice 704) are based on the 24 hour return interval rainfalls. Table 12 below provides the maximum rainfall depths for different return periods and durations. Table 12 : Design rainfall depths Duration 1 Day (24h) Delmas Return Period Rainfall (mm) 1:2y 1:5y 1:10y 1:20y 1:50y 1:100y 54 75 90 107 131 151 PCSWMM has been utilized for storm water analysis. It is a hydrological and hydraulic simulation program using the kinematic method to compute overland runoff and to analyze and quantify the catchment peak storm water discharges. The soil parameters utilized in PCSWMM is presented in Table 13 below: Table 13 : Soil parameters SCS Method Soil Classification Veld Code Hu26 Soil form Hutton A Soil Series Msinga Textural Class SClLm The soil on the site falls in the SCS Group A. The SCS Group A Horton’s maximum and minimum infiltration parameters are 34mm/hr and 25mm/hr respectively. The catchment parameters used in PCSWMM is presented in Table 14. Table 14 : Catchment parameters Sub-Catchment Attributes Imperv N Imperv N Perv Dstore Imp Dstore Perv Zero Perv Infiltration - Horton Max Infil. Rate Min Infil. Rate Decay Const. Drying Time (%) (mm) (mm) (%) Hauk & Gravel Roads- Land use Process Plant & Offices- 20 5 4 3 34 25 4 5 (mm/hr) (mm/hr) (1/hr) (days) Veld Dams - - 34 25 4 5 0 0 0 0 8.10.2.3 Design Criteria and Parameters The following standards and specifications were applied in addition to those mentioned in the Civil Infrastructure Design Criteria document:  SANS 1200: Standardized specification for civil engineering construction  SANRAL : Drainage Manual  Guidelines for Human Settlement Planning and Design Volume 2 ISBN:- Compiled under the patronage of the Department of Housing by the CSIR Building and Construction Technology Section The methodology that was followed in the design of the storm water system consisted of:  Identifying the overall storm water system comprising clean water areas, dirty water areas, dams, lined and unlined drains and road side drains.  Identifying the storm water catchments and determine their hydrological parameters/properties.  Applying the design criteria and assumptions as set out in Table 15. Table 15 : Storm water design criteria and parameters Design Flood Event Storm Recurrence Interval Major System 1:50 year Minor System 1:10 year (Plant) Low Points 1:10 years 681 mm Delmas 477309 W SCS Type 3 Dynamic Wave 1 Second Mean Annual Precipitation Rainfall Station Rainfall Type Routing Method Simulation Time Step Minor system channel criteria Type V-Drain Trapezium Min. Depth 0,075 0,30 Min. Width 0,60 0,60 Side Slope Not steeper than 1: 3 Not steeper than 1:1,5 Min. Grade 1:100` 1:100 Lining Concrete / earth Concrete Mannings ‘n’ 0,013 / 0,025 0,013 Minor system channel criteria Description Value Type Trapezuim Min. Width 1,5m Side Slope 1:1,5 Min. Grade 1:100 (minimum velocity = 0,6 m/s) Mannings ‘n’ Concrete 0,013 Earth 0,025 Box Drains 0,20 0,30 Vertical 1:100 Concrete 0,013 A dual drainage system for major and minor storms will be applied. Both systems will comprise mainly surface drainage elements. The minor system comprises of roads and side drains with pipes and culverts only used to convey water across roads. It will be designed for the 10 year storm. The major system comprises channels and canals which are fed from the minor system and will be designed for the 1:50 year storm. 8.10.2.4 Storm water drainage layout and description The clean water area (CWA) is drained by six clean water drains (CWD) as tabulated in Table16 and Figure 16 below: Table 16 : Clean water area storm water system STORMWATER CHANNELS NAME CWD 1 CWD 1 CWD 2 CWD 3 CWD 4 CWD 4 CWD 5 CWD 6 PCD OF PCD OF CH TO CH. BW D TW S% VM/S J25 J33 J31 J19 J18 J21 J02 J02 DESIGN Q- - - - - - TC(E) - 0.40 1.5 0.5 4.5 0.27 0.60 PC - - 0.60 - - 0.27 1.25 TYPE NODES TC(C) PC TC(E) TC(E) TC(E) PC TC(E) TC(E) Figure 16 : Clean water drains The dirty water area (DWA) is drained by three dirty water drains (DWD) as tabulated in Table17 and Figure 17 below: Table 17 : Dirty water area storm water system STORMWATER CHANNELS TYPE NODES DESIGN Q BW D TW 5% VM/S DWD 1 NAME CH TO CH. TC(C) J24 0.26 0.6 0.3 1.51 1.0 1.67 DWD 1 TC(C) J8 1.46 1.5 0.3 2.4 1.0 2.48 DWD 1 TC(C) J40 2.53 1.5 0.50 3.0 1.0 2.93 DWD 1 BD(C) J40 2.53 1.5 0.6 1.5 1.0 3.09 DWD 2 TC(C) J8 0.33 0.6 0.3 1.5 1.0 1.67 DWD 3 PC J3 0.25 0.60 - - 1.0 1.73 DWD 3 TC(C) J39 1.00 1.5 0.4 2.7 1.0 2.21 DWD 3 BD J27 1.14 1.5 0.4 1.5 0.5 1.92 Figure 17 : Dirty water drains 8.10.3 POLLUTION CONTROL DAM 8.10.3.1 Objective The polluted water from the plant and stockpile areas must be contained in a pollution control dam. The PCD is sized to store the 1:50 year design flood with 800mm free-board allowance. An operating volume is to be allowed under the flood zone for the accumulation of the average rainfall that will accrue between pumping cycles. The pumps will start when the top of the operating level is reached and will continue until the pump cut off level is reached. The concept is presented in Figure 18 below: Figure 18 : Dam storage zones Settling ponds or silt traps are provided at the dam inlet to contain silt and bigger particles in the dirty water. 8.10.3.2 Design Criteria and Parameters The calculated 1:50 year runoff for the plant area generates a flood volume of 5 900m3. A dam of this size has been sited to the northeast of the plant platform, between the discard conveyor and the haul road tip ramp. The dam is cut 3.5m into the natural ground and the top of the dam wall is roughly flush with the plant platform level. A dual bay settling pond or silt trap is provided at the dam inlet, one bay for the plant area storm water and the other for the haul road storm water draining from the opposite direction. A silt collection slab is provided at the deep end of the dam with a small sump area for the suction end of the pumps. Two pumps are mounted on the dam wall with suction pipes fixed to a slab on the dam wall. An access ramp is provided so that a TLB can clean the silt collection area of the dam. An emergency overflow weir is provided in the same vicinity that connects directly to clean water drain (CWD 1). The Settling pond has been sized to settle the 0.05mm particle fraction for the 25mm depth of rain. It is generally accepted that most of the suspended solids will be transported in the first 25mm rainfall of a storm and that further rainfall will be relatively clean of silt. 8.10.3.3 Dam and silt trap layout and description The dam is lined with a composite liner as required by the environmental legislation. A sub soil drainage system is provided under the liner on the floor of the dam. This drains to a small pump sump with a submersible pump which empties it back into the pollution control dam when necessary. The sub soil system will prevent uplift of the liner system due to the shallow water table. A geocell layer filled with concrete is provided as a liner protection. An allowance of 300m3 has been added to the dam capacity to provide an operating volume for the dam, and a free board of 800 m has been allowed above the overflow level. The accumulation of the average monthly rainfall during the rainy season will slowly start filling up the operating zone of the dam. The dam should therefore be emptied whenever the top level of the operating zone is reached. This will leave the full flood volume capacity available in the event of a 1:50 year storm. The emptying of the dam into the process water system is an integral part of the overall water balance of the mine. A pump of 50m3/hour capacity will be provided for this task. Pumping at that rate for eighteen hours a day will empty the full dam in a week. At 50m3/hour it will take six hours to pump the operating volume away, so the pump will generally run in six hour cycles unless excess rain is experienced requiring a longer pumping period. A picture of the pollution control dam is presented in Figure 19. Figure 19 : Pollution control dam Dirty water drain 1 and 3 outlet into a dual bay settling pond situated at the low point to the west of the discard bin conveyor platform. The pond outlets directly into the pollution control dam. The configuration of the drainage system here lends itself to providing two bays rather than a complicated inlet configuration and one larger setting pond. The inlet side of each bay comprises of a lateral channel with a weir overflow which drops the water directly into the settling basin so that the inlet velocity is immediately reduced to zero. The basin width has been fixed at 5 meters and the length is fixed by the settlement requirement as calculated. Each bay of the setting pond overflows into a communal channel which is the inlet channel to the pollution control dam. Inlet flows deeper than 150 mm will bypass the lateral weir and are channeled directly into the pollution control dam. The design depth of the setting pond is fixed at 500mm. Two access ramps are provided for each bay to facilitate cleaning and desilting of the setting pond. The ramp slope is fixed at 1:8 and a front end loader or a TLB can drive in via one ramp and out on the other. A picture of the silt trap is presented in Figure 20. Figure 20 : Silt trap 8.10.4 ROAD STORM WATER DESIGN Storm water on the roads is not fully covered in the storm water design report although the runoff from the sub catchments form part of the overall storm water calculation which are fully reported in that document. Road drainage is collected via the side drains of the roads and discharged via field inlets or at discharge points, which link to the culverts provided under the roads. The storm water then joins the overall runoff for the other elements of the project. The design criteria and parameters for the road storm water is presented in Table 18. Table 18 : Design criteria for storm water management on the roads STORM EVENT Major culverts Design Flood event Minor culverts and drains Design Flood event 1:50 years open % Imperviousness 1:10 years Paved surfaced areas Gravel surfaced area Open un-vegetated area Open vegetated area 100% 70% 50% 30% OPEN DRAINS Type Lined drains Maximum slope 1:50 Minimum slope 1:200 Liner Type Concrete lined drains where flow velocities exceeds 0,7 m/s Minimum slope 1:150 UNDERGROUND SYSTEM 8.10.5 Type Culvert Concrete pipe or portal type; to suit loading application Minimum Size 600 mm diameter Minimum grade 1:200 Minimum cover As per design Bedding SANS for rigid pipes SEWERAGE 8.10.5.1 Objective The main elements of the Xxxx sewer system to collect sewerage and waste water consists of the following elements:    Gravity sewerage reticulation network Pump station Sewerage treatment package plant 8.10.5.2 Design Criteria and Parameters The design of the sewerage system is according to the criteria and parameters as set out in the Civil Infrastructure Design Criteria, as well as the following Documents:    SANS 0252: Water Supply and Drainage for Buildings SANS 10400: The Application of the National Building Regulations Guidelines for Human Settlement: The minimum sewer design criteria is presented in Table 19 below: Table 19 : Minimum design criteria for sewer systems FLOW Source Administration office, ablutions, kitchens, workshops, etc. No of people To comply with the latest human resources organogram Usage Litre/person/day : 70 (SANS 10252-2: 1993 T9) Peak Factor 2,5 Allowance for infiltration 15 % PIPES Pipes Type Pipe gradients Nominal minimum velocity Flow Calculation Minimum size for reticulation (nominal diameter) Minimum size for building connection (nominal diameter) Minimum for waste water pipes (nominal diameter) PVC solid wall class 34 (400 kPa) pipes Minimum grade 160 mm 110 mm 40mm 1:100 Maximum grade 1:10 At full flow 0,75 m/sec Manning Equation Mannings ‘n’ 70% full, measured in terms of flow depth, at total design flow Minimum at full flow 0.013 80 m Fall Maximum Spacing Precast concrete ring manholes Alternatively concrete manholes can be replaced with brick or pre-fab poly ethylene manholes Concrete with steel lip ring – heavy duty Minimum fall through manholes Depth Minimum 0,5 m Pipe bedding Bedding as per SANS 1200 LB Class B Roughness Total design flow Velocity 0.7 m/s MANHOLES Manholes Type Covers 1050 mm  560 mm  50 mm 8.10.5.3 Sewer layout and description The sewer reticulation network consists of gravity lines collecting sewerage from the offices and change house. Changes in direction will be done in precast manholes at every bend. Sewerage will be collected in the pump station with a capacity of 100m3. Sewerage will be pumped to the sewer treatment package plant. The sewer system description is presented in Table 20 and the layout is presented in Figure 21. Table 20: Sewer system description Parameter Description Value Source Administration office, ablutions, etc. Amount People allowed for 285 Minimum size for reticulation 160mm Minimum building connection (nominal diameter) 110mm Minimum waste water pipes 40mm PIPES Type PVC solid wall class 34 (400 kPa) pipes Maximum grade 1:120 (0, 83%) 1:25 (4%) At full flow 0,70 m/sec 0,013 MANHOLES Manning Equation n-value 70% full, measured in terms of flow depth, at total design flow Maximum Spacing Type Precast Manholes Covers Concrete slab Fall Minimum fall through manholes 50mm Depth Minimum 0,5m Pipe Bedding Bedding as per SANS 1200LB Class B Minimum grade Pipe gradients Nominal minimum velocity Flow Calc Total design flow Figure 21 : Sewer layout 0.75 m/s 80m 8.11 COMMUNICATIONS (RADIO’S, TELEPHONE) (INTERNAL/ EXTERNAL) No communications has been included in the infrastructure scope. 8.12 OFFICES (FURNITURE, COMPUTERS, OFFICE EQUIPMENT, ETC.) Two prefabricated buildings will be constructed as a general office at the work shop and for the control room. The pre-fabricated buildings are founded within a platform. Specified layer work beneath the structures will allow for a safe bearing capacity of 100kPa. The pre-fabricated units will be assembled on a 100mm thick surface bed. The surface bed is mesh-reinforced and contains a thickening with a depth of 250mm along slab edge. The outside dimensions of the general office is 41.8m by 12.3m and include offices for management, technical staff, admin staff, meeting rooms, a kitchen and ablution facilities’ Figure 19 presents a plan layout of the office. The control room office consist of two stories. The ground floor is 21.5m by 10.5m and the upper floor is 11.4m by 10.5m. The ground floor contain offices and admin facilities with the control room on the upper floor. Figures 23 and 24 presents layouts of the ground and upper floors respectively. All office furniture, computers, equipment etc. will be supplied by Xxxx. Figure 22 : General office layout Figure 23 : Control office ground floor layout Figure 24 : Control office ground floor layout 8.13 WAREHOUSING (SPARE PARTS) No dedicated warehouse has been included in the infrastructure scope but a minimal number of critical spares will be stored in the workshop. An open, fenced laydown area was allowed for next to the workshop 8.14 ACCOMMODATION (GUEST HOUSE, SPORTING FACILITIES, CLUB, ETC.) No accommodation facilities has been included in the infrastructure scope. 8.15 CHANGE HOUSES The change house will be constructed as two dedicated prefabricated buildings with all the facilities included such as showers, ablutions, showers etc. Provision will be made for separate male and female facilities and a laundry unit/wash house. The pre-fabricated buildings are founded within a platform. Specified layer work beneath the structures will allow for a safe bearing capacity of 100kPa. The pre-fabricated units will be assembled on a 100mm thick surface bed. The surface bed is mesh-reinforced and contains a thickening with a depth of 250mm along slab edge. The outside dimensions of the change house containing the female facilities and the laundry is 29.7m by 10.7m. Figure 25 presents a plan layout of the building. The male change house is 17.4m by 10.7m. Figure 26 presents a plan layout of the building. All other equipment etc. that is not part of the fittings, will be supplied by Xxxx Figure 25 : Female change house and laundry floor layout Figure 26 : Male change house floor layout 8.16 LABORATORY No laboratory has been included in the infrastructure scope. 8.17 SECURITY (FENCES, LIGHTS) The OI project will be executed within the existing security area of Xxxx and no additional security systems is required. Fencing will be allowed for the PC Dam. 8.18 EXPORT FACILITY No export facility has been included in the infrastructure scope. 8.19 TEMPORARY SERVICES Contractor’s yard A platform area of 400m by 175m will be provided south of the workshop and office platform to serve as the contractor’s laydown area and construction offices. All the temporary infrastructure services such as water, sewer and electricity to the area will be constructed by earthworks contractor. The contractor(s) is also responsible to provide all offices, equipment, furniture connections to the services etc. that may be needed. Figure 27 show the contractor’s laydown area. Figure 27 : Contractor’s laydown area 8.20 RESCUE MEDICAL FACILITIES The existing rescue and medical facilities at Xxxx will also serve the OI project. 8.21 LANDING STRIP No landing strip has been included in the infrastructure scope. 8.22 WATER DISCHARGE FACILITIES No water discharge facilities has been included in the infrastructure scope. 8.23 MANAGEMENT INFORMATION SYSTEMS The existing management information systems will be utilized and any new information system infrastructure that may be needed will be supplied by Xxxx or others.