Making deep mining safer: flexible spray-on liner could replace shotcrete.

• Author: MacDonald, Darren
• Position: SUDBURY

With the future of mining in Sudbury dependent on finding ways to extract ore from deeper underground, a local invention offers hope that it can, one day, be done safer, cheaper and more quickly.

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The Canadian Mining Industry Research Organization - CAMIRO - is developing a spray-on liner that would take the place of the shotcrete and screens traditionally used to hold underground tunnels in place. Four millimetres of the bright orange, polyurethane compound would be sprayed onto the walls and ceilings underground by a robot adapted for mining use from the automotive industry.

CAMIRO is a Sudbury-based not-for-profit organization run by the mining industry to manage collaborative mining research.

Originally built to spray paint onto cars, the $60,000 robots would be upgraded with scanning and other software so it could coat the area with the liner without any humans being present. MTI Inc. of Sudbury has been given the job of coming up with a carrier for the robot, which is currently transported using a scoop tram.

Charles Graham, managing director of CAMIRO, said the liner has several potential advantages over current practices. Unlike shotcrete, the polyurethane liner is flexible.

"If the rock starts to move, it needs a support system in place that will move with it," Graham said. "Shotcrete and other products that we use have a limited amount of stretch before they fail. This product is flexible, but still extremely strong."

So instead of collapsing it there's a rock burst, the liner should be able to stretch, but not break, keeping the tunnel clear and miners safe.

"It allows the rock to deform. We know the rock will move, but as long as the liner is moving with the rock, the chances of it staying together are much higher."

The product could have huge implications for mining, Graham said, if CAMIRO is able to test it successfully and bring it to market.

"We expect the seismicity to increase as we mine deeper," he said. 'And the rock deformations along with it."

On Aug. 9, Rick Bartolucci, Sudbury MPP and the minister of Northern Development and Mines, announced $300,000 to help fund testing of the liner. Drawn from the Northern Ontario Heritage Fund, the cash will be matched by Vale and Xstrata Copper, who combined are also providing $300,000 for research.

Speaking at MTI's underground research facility in Lively, Bartolucci said supporting mining research is key to the health of the industry.

"It's great to be...