JOHANNESBURG (miningweekly.com) – Aim-listed Weatherly International’s Tschudi openpit copper mine, in Namibia, delivered 3 641 t of copper cathode in the quarter ended September 30, in line with expectations informed by the excessive rates of groundwater inflow into the openpit.

Although output for the first quarter of the 2017 financial year was 14.3% below the nameplate rate of 1 417 t/m, as expected, the company still expects to achieve the nameplate copper output rate by the end of the December quarter.

"After recording such a strong performance in the March quarter, we are disappointed that we were unable to anticipate such high groundwater inflow rates at Tschudi, and have consequently spoiled the company's record of beating our guidance,” Weatherly CEO Craig Thomas said on Thursday.

He noted, however, that the operating team was fully focused on meeting, or exceeding, the revised guidance and on again demonstrating the capabilities of the Tschudi operation.

The mine had produced 4 442 t of copper cathode in the quarter ended March 31 –  4% above its nameplate production rate of 17 000 t/y.

The company, however, reported in July that openpit mining operations had encountered groundwater inflow rates that exceeded the highest rates indicated in hydrogeological studies conducted as part of the bankable feasibility study. 

These excessive inflow rates had caused delays in mining the scheduled ore volumes to deliver to the heap leach operation, which, in turn, resulted in lower copper output. 

As a result of the decreased production in the September quarter, additional costs to manage the groundwater inflow and adverse exchange rate movements, C1 costs for the quarter increased to $5 073/t.

GROUNDWATER MANAGEMENT
Upgraded in-pit groundwater management systems and infrastructure have been commissioned as planned, and mining is proceeding according to the revised schedule, the company reported on Thursday.

The focus is now on long-term groundwater management systems including the introduction of dewatering boreholes within and/or outside the pits, the company stated, adding that it was confident in its ability to manage groundwater in the long term.