With the largest mineral resources of any country in the Persian Gulf region, Saudi Arabia is a land rich in gold and other precious metals, as well as petroleum. But most of the gold deposits are located in remote areas far from the country’s electric grid. This makes the mining and processing of the ore at these sites dependent on on-site power generation.
The Bulghah gold mine at Huqrah-As Safra, Saudi Arabia, began production in late 2002, as one of the resources surrounding the existing Al-Sukhaybarat gold mine — thought to be part of the fabled King Solomon’s Mines.
Operating 24 hours a day and 365 days a year, and located 550 km (342 miles) northwest of Riyadh, the Bulghah gold mine relies on self-generated electricity to power a vast array of pumps, conveyor systems and crushers as well as lighting and all miscellaneous electric equipment at the site. To do this, the mine generates all of its electric power using Rental Power units from Cummins Power Generation.
Bulghah is an open-pit mine and uses the ‘heap leach’ method of gold extraction. An elaborate electric-powered conveyor system transports the crushed gold ore to a plastic-lined pit to create a large pile of crushed ore. A solution of chemicals that dissolves the gold in the ore is pumped over the heap and allowed to filter down through the pile, where the solution is collected and further refined to produce pure gold.
Using this method, the mine produces approximately 82,000 ounces of gold annually.
Prime power system
Supplying electricity for this massive operation is a power system composed of seven CP1250-D6 containerized PowerCommand generator sets from Cummins. Each generator set is prime-rated at 1,000 kW for a total system capacity of 7 MW.
Depending on the electrical load, only five or six of the generator sets operate at any given time. This allows at least one generator to be offline for maintenance, or in a standby mode, thus guaranteeing a higher level of reliability for a power system that must run continuously.
“The owner of the mine did not want to undertake the day-to-day operation of the power system, so they contracted with our distributor in Saudi Arabia to install, commission and operate the system,” says Don Watson, rental director for Cummins Power Generation in Europe, the Middle East and Africa. “The station has been operating for over three years already without a single loss of power or interruption of the mining or processing.”
Maintenance and operation
Under the operating agreement, General Contracting Company, the Cummins Power Generation distributor in Saudi Arabia, operates the system and performs all the necessary maintenance. Local environmental conditions can be harsh. Blowing dust can clog air filters, and high summertime temperatures reaching 55*C (131*F) require careful attention to generator maintenance. Oil and filter changes are made after every 250 hours of operation.
The seven generator sets are powered by the Cummins KTA50-G3 engine, a 50-litre diesel engine used in thousands of power generation installations worldwide, ranging from on-site prime power to emergency standby power for critical applications. Operating at 1,800 rpm and producing electricity at 60 Hz, the generator sets are easy to start, synchronize and run due to the digital PowerCommand control systems on each generator set. All-digital control improves reliability under extreme operating conditions by significantly reducing analogue components and single points of failure.
The power system is installed as a long-term equipment rental for a period of 10 years and includes an operating and maintenance agreement with the local distributor.
Saudi Arabia has spearheaded development of the mining sector as part of a program of diversification away from petroleum. The government’s objectives for the mining sector include establishing industries for extracting and processing the minerals, and developing the transportation infrastructure.
It is estimated that Saudi Arabia has close to 20 million tons of recoverable gold ore, and according to a government website, non-oil mineral activity is expected to grow at a rate of 9.1% annually.
The operators of the Bulghah gold mine are pleased with the reliable operation of their 7-MW prime power system, as it allows the mine to operate efficiently and economically even though it is outside the reach of the country’s electric grid.
Cummins Power Generation of Minneapolis, Minn., a subsidiary of Cummins Inc., supplies alternators, generator-drive engines and temporary or permanent pre-integrated power systems combining generator sets and power control and transfer technologies. For more information, visit www.cumminspower.com/rental.