Africa Mine GT Sizing for Life of Mine

Start From a Year-by-Year Load Curve

A single maximum-demand figure is not a design basis. Break your load into its drivers: the processing plant and its expansions, pit or underground dewatering, ventilation that grows with depth, hoisting, workshops, and the camp and town supply. Then place each driver on the mine schedule, year by year, so you can see when demand rises, when it plateaus and when it starts to fall toward closure.

Include the awkward loads. Large mill motors and conveyor starts set your transient requirements, and dewatering often runs continuously even when the plant is down. Ask your planners for low, base and high cases, because a feasibility study’s base case rarely survives the first years of operation unchanged. The spread between those cases is exactly what your phasing has to absorb.

Set Firm Capacity, Then Phase It

Firm capacity is the load you can carry with your largest unit out of service. For an island-mode mine with no grid behind it, that is the number that matters, not the nameplate total. Many stations look generous on paper and fall short the moment one machine trips while another is in planned maintenance. Decide which loads are critical, which can be shed and in what order, and size firm capacity to the critical list plus a growth margin you can justify to your board.

Then phase the build. A first phase sized for the early years, with space, gas supply, cooling and switchgear bays reserved for later units, protects your capital without boxing you in. Tie each expansion to a trigger in the mine plan, such as a plant upgrade or the start of underground development, and record the lead time each phase needs so procurement starts early enough.

Give gas supply the same phasing logic. Your pipeline or LNG contract, the gas reception skid and any compression should be sized for where the station is going, or at least designed so they can be extended without a long shutdown.

Choose Units That Fit the Curve, and Plan the Exit

Unit size drives everything. A few large machines usually run cheaper per megawatt but leave you exposed when one trips; more, smaller units track a changing load curve better and make maintenance cover easier. Your gas turbine generators can be mixed with natural gas engines/stations, which handle part load and camp supply well, while a remanufactured GE Frame 6B or other used/new gas turbines can carry base load through the middle years. Altitude and ambient temperature derate every option, so size on site conditions, not catalogue ratings.

Plan the back end too. As the pit winds down, surplus units can be relocated to another operation, sold or kept as cover, and that option has real value when the machines were well maintained. If your region later attracts larger loads, from processing hubs to sites seeking AI gas turbines, hyperscale generators or gas turbines for compute, phased blocks such as the New USP&E FX-45 45MW Modular Gas Turbine for the Hyperscale Data Center sector in the USA, for 50 Hz and 60 Hz with capacity slots from 2028, can be planned under one hyperscale EPC/O&M team.