Backfill valves for underground copper mines

Three years ago, a project at the Kamoa copper mine in the Democratic Republic of Congo showed the application of high-pressure valves in backfill conveyance. The main takeaway from the installation was that the valves have to meet the following features to excel: severe service zero cavity, zero dead space isolation, dump and diversion valves rated to 250 Bar.

Tailings disposal management has become an important operational objective, as mining companies strive to meet stringent environmental compliance requirements. Interestingly, converting the tailings into backfill has emerged as a cost-effective way of putting the waste to good use – turning trash into a treasure of sorts if you will. The paste fills out mined-out areas underground like stopes that pose a hazard to employees and can interrupt work.

Paste backfill is made by mixing a binding agent, water, and tailings, or just water and tailings. The option to use depends on a mine’s particular requirements.

An elaborate task

However, a mine faces an elaborate task in conveying the paste backfill using suitable tools like valves and pumps. This is because of the material’s abrasive and corrosive nature and high-pressure properties, which can test a product’s tolerance to the extreme.

But what works perfectly, or near perfectly (truth be told, there is no perfect product)?

Learning from a project in the DRC

It is plausible to learn from applications in practical project situations. There are scores of projects where valves have been applied for backfill conveyance. And it has worked like a charm. These could provide ample information to base on.

But we reference a project where the team involved was keen to share their details on valve requirements they were privy to. And that is the Kamoa Copper Mine project in the Democratic Republic of Congo (DRC).

Mammoth valve test

Ordinarily, performing this duty in an underground copper mine can be a mammoth test for valves, which can succumb to harsh conditions and fail, stalling progress. This is not a situation mine management would stomach with production at its peak.

The requirements

So, pump selection had to be meticulous, with no margin for error. The selected valves were to allow a mine to go deeper underground and sustain higher pump pressures. They had to fulfill requirements relating to high-pressure range, sizes, connection types, functionality, and resistance to wear.

The specifications

After careful consideration, the team recommended high-pressure valves, with the following specs – severe service zero cavity, zero dead space isolation, dump and diversion valves rated to 250 Bar. This is more or less the standard requirement of valves for the conveyance of abrasive, corrosive, and high-pressure backfill in underground copper mining environments in African mining.

So far, three years after installation, the valves are still in perfect working condition. This proves that correct product specs guarantee a seamless backfill conveyance in extreme conditions.