Orion Minerals says it has awarded a six-month trial mining contract to P2 Mining, a subsidiary of South Africa-based mining contractor Newrak Mining Group, to undertake the early works trial underground mining program at the Prieska copper zinc mine (PCZM) in the Northern Cape Province of South Africa.

The trial mining will target the +105 Level Crown Pillar, using conventional and alternative underground mining methods, including the use of an ITC120 continuous loader and two 20-t bi-directional trucks in the underground development cycle.

The trial mining will comprise 120 m of footwall ramp development, before accessing the high-grade supergene ore of the +105 block with ore development along strike for 150 m on either side of the primary access as the primary in a cut-and fill mining cycle.

In addition, the Newrak contract also covers the opening of the 143 Level historical stope draw-points for selective loading and hauling to surface of broken ore remaining in the stopes, in order to perform bulk sampling and metallurgical trials on the material. If successful, this exercise will continue to build a stockpile on surface for future processing once the concentrator plant is commissioned.

Orion’s Managing Director and CEO, Errol Smart, said: “This is a tremendously exciting period for Orion as we move to active trial mining at Prieska and start our transition from developer to operating mining company. We have spent the past two months completing essential preparations, such as installing underground refuge chambers, upgrading hoisting capacity of the emergency escapeway to surface and sourcing and installing key ventilation equipment.

“With these essential safety and environmental preparations now complete, we can finally mobilise the mining contractor to commence drilling, blasting and hauling ore to surface.

“The trial mining phase will also see Orion apply our core philosophy of bringing proven, innovative methods matched with appropriate skills and experience to our operations, while at the same time training and upskilling our host community members so that we can ultimately source our staff locally. We also aim to develop local enterprises to service Orion’s mines and the South African mining industry, encouraging our service providers and contractors to support these endeavours and contribute to the skills transfer and enterprise development.”

Orion will be testing an ITC120 continuous loader supported by two specifically paired bi-directional drive trucks at the PCZM operation. The ITC120 loader shows great promise in delivering improved cycle times and development rates compared with conventional mechanised rock loading and hauling methods, according to Orion. It is envisaged that these improvements can deliver significant a positive impact on both the +105 and the Prieska Deeps mining once dewatering has been completed.

The ITC120 continuous loader and the PAUS 20 t dump trucks are supplied via Hurst Mine Tec (HMTEC), the newly established local representative for Swiss group ITC. HMTEC is introducing the European tunnelling technology into South Africa for the first time and will support the imported equipment locally.

Orion said: “During development, the combination of the continuous loader with the two bi-directional drive dump trucks is expected to show significant improvements in safety, cycle time reduction and lowering development costs, with one machine doing all scaling, mucking and loading in a face. Direct conveyor loading into dump trucks driven into the face removes the need for shuttling LHDs and removes the requirement for loading and passing bays in the development tunnels. The bi-directional drive trucks also improve safety, removing the need for reversing long distances by LHDs. Importantly, the number of engines running is reduced, with a resulting decrease in exhaust gases and heat.”

The continuous loader and paired bi-directional trucks are anticipated to have particular application in the drift-and-fill stopes that will be prevalent in both the +105 mining block and in the shallow-dipping Prieska Deeps ore blocks, Orion added.

The anticipated improvements in development cycle time and associated cost reductions will be demonstrated during trial mining and carried forward to the revised bankable feasibility study (BFS) for the early mining start and planned future deeps mining at PCZM.

The 2020 updated BFS outlined an initial 12-year, 2.4 Mt/y operation targeting 22,000 t/y of copper and 70,000 t/y of zinc, with life of mine production slated at 226,000 t of copper and 680,000 t of zinc.