How far from the grid does a mine have to be before its own power plant is the cheaper answer? For West Gold Mining Limited the line was drawn at nearly 300 km. Its new gold mine in the Aktobe region of Kazakhstan has no electrical infrastructure within reach, and Caterpillar announced on 7 October that the mine will run on two Cat G3500K series gas generator sets in prime power, supplied and supported by the dealer Borusan Cat. A grid extension was studied; distance and cost ruled it out, and a feasibility study found that a self-contained gas plant would serve both the start-up load and the mine's expansion plans.
Island Mode From Day One
The two sets run in island mode, with no utility connection to lean on. Caterpillar describes the plant as built for growth: it is meant to be extended as production rises, rather than sized once for the opening load. According to Power Progress, the G3500K series covers 1.5 to 2.5 electrical MW continuous per set; Caterpillar's release does not give the installed capacity. EnergyTech adds that the K series runs on natural gas, propane, hydrogen blends, coal-bed methane and biogas, and can be set up for combined heat and power where a site needs it.
The sets come in containerized enclosures, chosen for a site where winter reaches -30 °C and summer passes 30 °C. Beken Erik, chief executive of West Gold Mining, said the company needed a plant that could run independently of the grid while supporting its long-term plans, and that the local support gave it confidence in the performance and in future scaling. Melissa Busen, senior vice president of Cat Electric Power, called it an example of practical energy problems solved with scalable power systems and local service.
Why The Dealer Is In The Headline
Caterpillar makes a point of Borusan Cat's part in the project. The dealer covers Turkey, Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan and other parts of Central Asia, did the technical work with the customer and will sign a Customer Value Agreement after installation and commissioning to cover maintenance. West Gold Mining is quoted as having put local service, parts availability and people on the ground ahead of product data when it chose the supplier.
That is the right order for a plant 300 km from the nearest city. On a grid-connected site a failed part costs a day; here it costs production until the part and the technician arrive, and both travel the same road as everything else.
A 60-Degree Range Around One Machine
The temperature band in the release deserves a second look. A plant that has to start and hold rated load at -30 °C and carry the same load above 30 °C sees both ends of the design: cold starting, fuel gas conditioning and freeze protection in winter; air density, cooling-air temperature and radiator capacity in summer. The summer end sets the size of the cooling equipment, the winter end its controls and bypasses, and both belong in the enquiry if the packager is to get them right. The same question comes up on off-grid data center plants, which are island-mode gas plants by another name.
Ask the supplier one thing before the order: what is the cooling-air temperature in the hottest week, measured at the plant, not at the nearest airport.
Sources: Caterpillar, Power Progress, EnergyTech
