TGL Provides SA's 1st BOM Power Plant for Platinum Mine
14 January 2009
Gauteng-based engineering firm Thuthuka Group Limited (TGL) has been awarded the Build, Operate and Maintain (BOM) contract to provide a 10 MVA power plant for Boynton Platinum's Pilanesberg Mine, located some 60 km north-west of Rustenburg.
TGL's Eddie Simes explains: "Pilanesberg Platinum Mines, a wholly owned subsidiary of Boynton Platinum, negotiated a 37 MW power supply from Eskom during the concept design phase of the mining plant. Subsequently, the detail design and procurement of plant equipment necessitated the demand side of the plant at 36.9 kW for normal full load capacity operations. This means that the mine will run at maximum power provided by Eskom."
Boynton Platinum contracted TGL to provide a 10 MVA independent diesel-fired power plant for :
- standby power - in case of total Eskom failure the plant will supply the essential UG 2 operations of the mine;
- peak shaving power owing to the limited Eskom supply provided to the mine at 37 MW;
- a base load supply in case of a limited (10 per cent) load-shedding request to the mines from Eskom, and to increase the mining capacity to 110 per cent of the design load pending price of platinum per fine ounce.
The stationary power plant will be constructed and operated by TGL, who will provide all necessary operation and maintenance and to provide electricity as part of the off-take agreement with the mine.
Description of the works
As this is not a standby power plant, the plant will generate power parallel with Eskom on the demand side of the mine through a 10 MVA incoming circuit breaker. The plant will therefore synchronise with Eskom as the primary power supply.
The plant itself consists of seven generator sets, each comprising a 1 245 kWe diesel-driven Mitsubishi engine with a Stamford alternator. The latter provides 400 volts at 50 Hz. The 400 volts are stepped up individually by seven 400V/11 kV transformers. The 11 kV is then synchronised with the Eskom power supply and, through Matelec switchgear, protection, monitoring and control relays power is supplied to Pilanesberg Platinum Mines.
Engen is providing the diesel for the seven engines, each of which will consume 360 litres of diesel per hour at full operation, totalling 2 520 litres of diesel per hour. The Capex of the plant comes to between R6 500 and R10 000 per kWe, depending on the final design requirements of the client.
The scope of the project awarded to TGL consists of the engineering design civil works, the foundations for the engines, the engine room - which consists of a steel structure and face brick, an MV switchgear room, a control room, a fire room, two 100 cubic metre tanks, one 20 cubic metre tank and assorted lubrication, oil and fuel tanks.
Simes says, "The essence of TGL's design is simplicity, safety and reliability. The equipment is designed to prevent accidental contact with moving, hot or tensional parts and to minimise ingress of dust and dirt. The structure and layout design of the power plant permits access to all parts for inspection, maintenance and repair."
The project was officially awarded on 20 May 2008, all engineering and design was completed by the end of July 2008, the civil works started in the first week of August and the mechanical engineering works started in September with completion scheduled for mid 2009. The civil works are scheduled for completion in mid February 2009. In January, equipment deliveries are scheduled for engines, transformers, MV switchgear panels, SCADA systems and process management systems. The commissioning and integration of the power plant is to take place in February and March, with hot commissioning of the plant scheduled for March/April 2009. The plant is expected to be fully operational by mid April.
Operation and Maintenance of the Plant
The delivery of the power plant will be managed by a dedicated project team, comprising a Plant Operations manager who has the overall responsibility for the delivery, and who is assisted by project engineers for the main technical disciplines.
Upon installation, the plant will be manned on a 24 hour basis by operators who will work in eight-hour shifts. The team will include a mechanical/ electrical engineer, two mechanical technicians and two electrical electricians.
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