Indonesian Copper Mining Project

PPM pinpoints gains for Indonesian copper project

PPM Global is continuing to play a key role in the successful ramp up of production at the Wetar Copper Project in Indonesia by identifying a number of small, but significant improvements.

Copper process solution ponds area

Alongside Wetar copper project management in Indonesia, a new risk assessment was conducted to assess daily duties working in and around the copper process solution ponds. This was deemed necessary due to higher than normal movement around the ponds presenting a higher risk to operators.

PPM assisted in the assessment and training activities of Indonesian process plant operators, originating from this risk review process.

Safety ropes were installed around the ponds. As an acidic environment, all ponds are HDPE lined. The use of this material can create a slippery working area in certain conditions. If a slip occurs and a process plant operator falls into the pond, they can use the safety ropes to pull themselves out of the acid to safety.

When acid is added to water the heat generated can be quite significant. This can melt the HDPE liner if the injection point is at surface near the liner. As such, a float was installed on the acid – mixing system – feed line. The acid injection point was relocated near the centre of the pond. This ensures that the acid injection mixing point is well away from the pond’s edge. Benefits include prevention of possible liner damage resulting in environmental and personnel hazards by ensuring that the mixing of acid and solutions happens well within the pond.

Copper Heap leach stacking Indonesia

Reviews of how the heap leach was being stacked with fresh ore, prompted a simple but effective change to the stacking equipment.

As a visual aid to assist the operators in stacking copper ore at the correct height, PPM recommended the project team install ball and chains hanging from the conveyor frame on the “stinger” on the ore stacker.

The “ball and chain” provided a simple guide to stacking height such that once the copper ore reached the ball the plant operator would move the stacker slightly to the side and continue stacking.

Consistent stacking of the ore height improves the copper ore heap leaching process in several ways. A well-stacked heap reduces ponding once under irrigation. It avoids having earthmoving equipment level the top which can cause further compaction. It also makes operation of the stacker easier and more efficient by ensuring stacked tonnes meet production targets.

Electrowinning cell house

A detailed audit around the electrowinning area identified some key actions to improve its operation and efficiency.

Busbars were cleaned thereby improving electrical contacts and reducing hot spots. Capping boards were replaced, as damaged capping boards cause electrode misalignment. This in turn can increase copper harvesting times. Cell manifolds were flushed and unblocked thereby improving flows throughout the cell house.

All the above electrowinning tasks are an ongoing process to maintain copper quality “LME Grade A” and the safety and effectiveness of copper harvesting.

PPM with Wetar management assisted in developing a SOP (Safe Operating Procedure) to identify the daily steps to help maintain an effective cell house operation.

These steps included ensuring that the cell-house was hosed down twice per shift to reduce the likelihood of reduced current efficiency (CE). Reduced CE can be caused by crystals and salts building up on the electrode hanger bars and intermediate busbars.

To further assist with maintaining high CE, the SOP also detailed the need for regular checks using an infrared temperature gun to check for “hot spots” caused by irregular growth on the copper cathode surface.

"Reviews of how the heap leach was being stacked with fresh ore prompted a simple but effective change to the stacking equipment."