JOHANNESBURG (miningweekly.com) – ASX-listed Kasbah Resources will revise its definitive feasibility study (DFS) for the Achmmach tin project, in Morocco, after having identified several project optimisation opportunities that have the potential to materially improve the project and reduce risk.
These opportunities mainly relate to site infrastructure, grinding, comminution and ore sorting. The company said on Tuesday that it had started test work associated with realising the opportunities and that a revised DFS would be published in the first half of 2018.
The company is considering some key changes to its 2016 small start option (SSO) DFS at the project, which includes a move away from a strategy of mining high-grade ore in the initial years to reduce mining risk associated with defining higher-grade areas.
Kasbah has engaged Entech Mining Consultants to revise the mining schedules and geotechnical parameters in the mine design. The company is now also departing from a staged start-up, using modularised equipment, to a plant that will start with a capacity of 750 000 t/y.
Further, Kasbah will also move away from the use of EDS mills to a conventional rod and ball mill configuration. As part of this change, consideration is being given to the use of high-pressure grinding roll (HPGR) technology to replace a rod mill.
HPGRs have the potential to significantly reduce power consumption and grinding media costs. In addition, HPGRs could replace the third stage of crushing and reduce the overall size and cost of the ball mill configuration.
A change to the plant location and layout to shorten haul distances from the mine is also being investigated, while a review of the tailings storage facility (TSF) design and location is under way.
Consulting company Golder will confirm the local geology and the geotechnical parameters necessary to build the TSF facility.
A change to the gravity separation process will also be implemented, whereby coarse and fines spiral feed will be treated independently rather than being combined, while Kasbah will also introduce resorting at the front of the processing plant.
“Ore sorting technology has progressed significantly over recent years with improved sensors and computing capacity and has the potential to increase the grade of ore entering the separation processes and as a result increase the recovery of tin in those circuits and lower operating costs,” the company explained.
The proposed initiatives, the company noted, were likely to result in higher up-front capital than the 2016 SSO DFS. However, the higher capital cost was expected to be offset by greater revenue in the initial years and a significant reduction in production risk.
Kasbah has endorsed a three-month test work programme to ensure that the optimisation opportunities are well understood ahead of their inclusion in the project scope.
The Achmmach project holds a mineral resource of around 15-million tonnes, an ore reserve of 6.5-million tonnes and a ten-year mine life with significant prospectivity both along strike and at depth.