Approaching underground safety from the surface

Minova CTPM pump unit for pumping injection chemicals from the surface.

Contact with chemicals, dangerous equipment and unpredictable surfaces all exist in underground mines, but Minova has found a way to reduce human exposure. Alex Gluyas writes.

Strata consolidation is a crucial aspect to the safety of any underground mining operation, as it provides stability around mine openings.

Underground mining in general is fraught with safety risks but the upside is enormous given some of the most prominent coal mines in the country lie beneath the earth’s surface.

Generally, the underground mining process involves creating tunnels from the surface into the mineral seam, which can exist hundreds of metres beneath the surface.

These tunnels are then used to transport machinery and equipment that assist in extracting the materials.

For Minova Australia, the introduction of the ‘surface to seam’ method for strata consolidation offers mining companies a new approach to ensuring the safety of its miners, which diverts from the conventional way.

According to the company’s commercial and operations manager, Dave Hewitt, the new technique is far more effective than the traditional system.

“Traditionally in underground coal and hard rock, when you do strata consolidation, the practise has always been to approach it from underground, which involves a lot of material handling in the underground environment,” he explains.

“That in itself has a lot of safety issues such as dealing with chemicals, different raw materials; there are a lot of exclusion zones and a lot of people in confined spaces.”

A mining industry push to try and undertake this process from the surface means Minova is now capable of offering its ‘surface to seam’ method, creating a huge opportunity for mining companies.

“Undertaking this from the surface eliminates people and reduces the potential exposure to chemicals in a confined space,” Hewitt says.

“It also removes a lot of machinery which always has the potential to hurt people and less people involved in the process means personnel can work on other areas of mine sites.”

The new approach focuses on what the company describes as ‘strata control’ which incorporates roof reinforcement, preventing rib failure and stabilising floor movement within site specifications.

Water ingress is a common way in which ground support systems can be compromised and the injection of chemicals from the surface is one solution Minova offers.

A pumpable crib can be filled from the surface in around 15 minutes.

 

This can also be applied to fill cavities in mines, as increasing pressure on rocks from mining activity and geotechnical conditions can cause fractured ground.

If not reinforced, incidents of rock fall or roof collapse can occur which presents danger to people, assets and infrastructure.

Minova anticipates that the process will cut the human footprint in half and Hewitt notes that the demand for the ‘surface to seam’ approach is already in the market.

Having already been approached by a company struggling with strata, Hewitt was questioned about what could be improved by pumping from the surface.

“Personnel-wise, there’s 37 shifts, 12-hour day and night shifts, just to move the product in and out of the mine – that takes a lot of people and equipment to look after just one part of the mine,” he says.

“There was also 37,000 drums of materials being lifted across rough ground and steel pallets that weigh 21 kilograms, so the potential for someone to hurt themselves is high.”

To improve the efficiency of the process, the surface to seam approach also utilises bulk handling, which minimises the number of trips being made.

As Minova looks to launch the surface to seam approach in underground coal mines, Hewitt believes the new method could extend beyond the coal mining sector and into other underground mining areas.

“Block cave mines are now using these chemicals, which they haven’t used in the past as they are starting to get very deep in these caves,” he says.

“To reduce the amount going underground would have significant benefits for an industry that doesn’t have as much experience.”

The new approach is symbolic of a wider industry focus on what Hewitt describes as “remote-type mining”, which involves controlling operations from more distant locations.

The aim is to reduce the exposure staff have to hazardous environments, machinery and chemicals.

For Hewitt, the equation is simple; “the more you can reduce your underground footprint in relation to human and loader interaction, the better off mine sites are.”

This article also appears in the Jul-Sep edition of  Safe to Work.

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