Canadian company Asante Gold has announced that it is reviewing a new mining technique for future application at its Kubi gold project in Ghana.
The new mining technique called Sustainable Mining by Drilling (SMD) is a two-stage drilling method that enables direct mining of narrow deposits. The technology is developed and commercialised by Anaconda Mining, in collaboration with Memorial University of Newfoundland. SMD utilises technology proven in other industries.
According to Anaconda, the concept is a complete surface mining option with a drilling rig as a main surface piece of equipment used in conjunction with several field proven down hole technologies. The mining process is divided into two campaigns: drilling the pilot holes and accurately mapping the vein and then enlarging the pilot holes to predetermined sizes to recover the ore. Using an inclined mast drilling rig an inclined pilot hole is to be drilled along the centre line of the vein (equidistant between the hanging wall and foot wall) with directional drilling system.
Steering the pilot holes live with survey tool will determine the current orientation and to refine 3D model of the vein used to plan the pilot hole enlargement. Once the pilot hole has been drilled, progressively larger hole-openers can be used to drill along the pilot hole’s trajectory up to 2m.
Anaconda says in a statement that the SMD technology is a ‘disruptor’ in that it reduces the cost to extract ore by 50% over conventional UG narrow mining techniques. It places the operator in a safe location on the surface; it can access areas not open to conventional mining; reduces the environmental footprint; and bypasses the crushing and grinding circuits by moving the +-2mm drill cuttings in a slurry direct to the mill.
According to Douglas MacQuarrie, president and CEO of Asante, the new SMD mining technique slashes the mining costs, development time and capital required to take near surface gold deposits to production. “Our Kubi Main Zone gold resource is located in one of the best and safest gold mining destinations in the world, is road and power accessible, has an average width of 2m, is near vertical and appears to be well suited for the application of this technique,” says MacQuarrie.
Previous metallurgical tests on Kubi mineralisation gave 35% to 40% recovery of the contained gold by gravity concentration from a coarse grind, which suggest a similar recovery might be expected directly from the SMD drill cuttings, giving a potential source of early cash flow.