ASX-listed copper miner Tiger Resources last month announced the operating performance of the solvent extraction and electrowinning (SX-EW) plant at its Kipoi copper project in the Democratic Republic of Congo (DRC) following completion of the first 12 months of cathode production, noting that May returned a record plant output, with 2 306 t of copper cathode produced.

The SX-EW plant was commissioned in May 2014, ramp-up of production to the 25 000-t-a-year nameplate design capacity was achieved by August of the same year, and since then the plant has continued to demonstrate an ability to produce LME Grade A equivalent quality cathode consistently at or above budgeted rates of production.

Kipoi Operating Initiatives
Following the first 12 months of SX-EW operations at Kipoi, the operations team identified areas where the plant can be debottlenecked to increase production and reduce operating costs.

These initiatives will be assessed with a view to being rolled out over the next 12 months and include limiting materials rehandling by using the overland conveyor from the former heavy mineral separation (HMS) plant to the agglomerator; using available current to the EW circuit through the addition of extra EW cells and bringing forward the HMS fines delivery through the addition of a small 40 t/h modular tank leach.

Tiger believes the combination of using the overland conveyor system and adding more EW cells alone could increase monthly production by as much as 30% for a modest capi- tal outlay. Further, the company holds that debottlenecking initiatives are both complementary and independent of any potential future expansion of operations at Kipoi from the current 25 000 t/y copper cathode operation.

The Kipoi operating team is realising the price benefits resulting from the growing supply of sulphuric acid available in the Southern African markets. Sulphuric acid is the principal reagent used to irrigate the heap-leach pads and is the second largest component of processing costs at Kipoi. Whereas 2015 budgets were set using $365/t as the assumed price for acid, long-term contracts have recently been entered into for delivery at a cost of $235/t. The future price of sulphuric acid remains under significant downward pressure.

During May, Tiger energised the recently installed 30 MVA transformer, which is now being run to provide grid power to Kipoi. This is a key milestone among a number of power supply initiatives Tiger is currently implementing, in order to access continuous grid supply from the second half of 2015 onwards in line with market guidance.