How this SA mine will boost production by a third

How this SA mine will boost production by a third

When it comes to large complex projects, trade-offs can seem inevitable. There are always competing stakeholders, competing priorities and resource or technology constraints. But this is why I’m watching Prominent Hill’s transformation from a trucking site to an electric hoisting operation so closely – the BHP project perfectly encapsulates the win-win opportunities that mining electrification and automation are increasingly delivering.

First announced two years ago, the Wira shaft expansion is now well advanced, with It is expected to be fully operational by the end of 2025.

Lay of the land

Having started as an open-pit mine 15 years ago, Prominent Hill now extends more than a kilometre underground, as miners have chased the rich copper, gold and silver ore bodies. It is currently moving more than 4.5 million tonnes a year, but with trucking costs rapidly increasing as the depth does, the whole operation was set to become uneconomical by 2033. ABB is supplying what is set to be Australia’s largest and most powerful hoist, capable of lifting almost 40 tonnes up a 1300m shaft in as little as 90 seconds.

In an environment where hard-fought single percentage points increases in efficiency or productivity can have material impacts on balance sheets, the predicted benefits electric hoisting will bring to Prominent Hill are staggering.

BHP is predicting double-digit increases in productivity, double-digit drops in operating costs and emissions, and significant safety improvements.

Productivity, sustainability and safety are vital to any mine, but have often been in tension with each other.

But Prominent Hill’s transformation shows the possibility of a triple win – smarter, more sustainable and safer operations.

Expanding productivity

The biggest attention-grabber about the Prominent Hill expansion is no doubt the boost in productivity. The electric hoist is set to expand the mine’s production capacity up to 6.5 million tonnes a year, an increase of more than a third. By allowing access to ore bodies impossible to exploit under the current trucking plan, the expansion will also extend the productive life of the mine by an estimated four years. But as big as this productivity boost is, the per-worker productivity boost is even bigger, thanks to a dramatic reduction in driving hours.

Maintenance and scheduling is also greatly simplified. With advanced remote monitoring and predictive maintenance capabilities, the Wira shaft hoist is expected to have more than 90% availability.

Where predictive maintenance truly shines in this context is with spare-parts logistics. With ongoing monitoring of wear and condition, operators are able to ensure they have the needed spare parts on hand when needed, minimising downtime and maintaining productive capacity.

Driving down costs

Of course, it’s no surprise that hoisting is vastly more energy efficient than trucking. Diesel engines are generally about 35% efficient in converting fuel energy into movement, and the haul trucks they power up ramps must generally cover seven horizontal metres for every metre they climb vertically.

In comparison, the electric motors in a hoist are about 95% efficient in converting electrical energy into movement, and the hoists they power move materials straight up.

But those simple facts don’t mean there aren’t further efficiency gains to be had. Hoist efficiency can also be enhanced by:

  • remote drivetrain health and monitoring services to predict maintenance and safety issues early
  • analysing speed, payload and energy consumption on each hoist cycle for further optimisation
  • using energy regeneration and storage to balance electrical network loads when operating the hoist

Strategies like these are why BHP is predicting that the move to electric hoisting will cut their operating costs by a fifth, with a drop in CO2 emissions of more than a quarter.1

With the increasing focus on circularity in all aspects of heavy industry, it’s also gratifying to know that the hoist will almost certainly outlive the mine. With proper servicing and upgrades, hoists can easily operate for a half-century or more, potentially moving from mine to mine as needed.

Setting safety standards

It’s no secret that haul trucks are a chief source of safety hazards on mine sites – one US study found that they were involved in one in five fatal mine-site accidents.2

But haulage accidents are one of most stubborn risks in mining, which is why we’re expecting the Prominent Hill hoist to have a significant impact on reportable events and incidents.

The safety boost goes well beyond simply reducing truck haulage and avoiding ever-deeper decline ramps.

The hoist itself will be one of the safest in the word, thanks to ABB Ability Safety Plus – the first hoist solution fully certified for Safety Integrity Level (SIL) 3 status.

Developed in strict accordance with the International “Safety of Machinery” standard IEC62061, the system has been rigorously examined and independently certified as achieving best-in-class safety and redundancy performance.

Of course, the same data analytics and monitoring that allow operators to maximise the productivity and efficiency of the hoist are also a boon for safety, allowing potential faults to be identified and remedied vastly quicker than is possible with a haul truck fleet.

It’s a fascinating time in mining

Miners are under pressure on multiple fronts. Shareholder, public and regulatory expectations on sustainability are ratcheting up. Safety regulations are growing tighter. Shortages of everything from skills to materials are making plans tougher to execute.

This is why seeing the real-world impact the right hoisting solution can have on a mine is so powerful. Solving a single problem is satisfying, but overcoming a whole suite of intersecting challenges without operational trade-offs brings a whole other level of satisfaction.

Considering that ABB installed its first electric mine hoist back in 1891, it might seem odd to talk about hoisting as part of the future of mining, but Prominent Hill shows that this is exactly the case.

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References

  •  Electric Hoisting at Prominent Hill, OZ Minerals, 2022.
  • Why Do Haul Truck Fatal Accidents Keep Occurring? Mineral Metal Explorer, 2021.

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