Australian coal producer, GVK Hancock, says it has been “searching the world” to investigate the most efficent and cost effective overburden mining methods available for its projects. The company states: “GVK Hancock set itself a goal to be the world leader in adopting proven global best practice and has been looking outside of the box regarding what methods it will adopt globally, not just in Australia. As a result, a combination of draglines and bucket wheel excavators (BWE) has been selected.” This development represents effectively a form of in-pit crushing and conveying (IPCC) solution, and the planned set-up is one option that has been discussed at length at IM Events IPCC conferences in recent years.

Dragline machines weighing up to 7,000 t each will be used along a 24 km strike-length at the Alpha coal project. Each step taken by the machines GVK Hancock plans to use is approximately 2.3 m and it can travel approximately 1.2 km in 12 hours on a flat surface. The company added: “Draglines have a high capital cost but in the right conditions provide the cheapest method of overburden removal as it can amount to less than half the cost of using trucks and shovels. GVK Hancock will also utilise BWEs to shift soft overburden material ahead of the draglines. This will involve approximately 30 km of conveyor belts to move material directly to the overburden dump.” As with draglines, BWEs are high capital cost machinery with low operating costs. A direct benefit of using BWEs is that it reduces GVK Hancock’s reliance on diesel powered machinery used in truck and shovel operations. “Our focus has been on reducing reliance on high cost inputs such as diesel and tyres. In Australia, BWEs are currently used in Victoria’s Latrobe Valley and are commonly used for mining in suitable conditions overseas.”

Surface miners will be used to mine all open-cut coal and will also be used to separate the thin waste bands between the coal seams. Surface miners were selected because they can complete this task most efficiently, allowing GVK Hancock to maximise the coal recovery and minimise waste dilution into the coal. By mining the coal seams cleanly, the company will minimise rejects handling which is both cost and time effective. In terms of suppliers, GVK Hancock at this stage only states that it has “engaged international experts to assist with equipment specification for these technologies, that will ensure our global competitiveness.”