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.
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 if 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 under Lively today,” he said, as reporters and officials looked on, everyone decked out in hard hats with miners lights on them and hazmat suits. “A thriving mining industry in Ontario will play a major role in bringing monies into the provincial and federal treasury ... It is a critical economic engine for Ontario.
“These investments make it possible to bring new products into the industry. It demonstrates to the world that we are leaders in the mining industry.”
Graham said NOHFC funding is key in the development of products such as the liner, as are developing industry partnerships. ABB Inc. provided the robot, and 3M makes the actual polyurethane compound. He said the idea for the liner has been around for 25 years, but coming up with the right formula that is strong and flexible enough to work underground has been a huge challenge.
Laboratory tests of the current compound have been very promising, Graham added, but now it needs to be tested underground.
“We have a lot of scientific muscle on the liner,” he said. “We’ve started over with the formulation and so we think we’re on to a more resilient product that will adhere better to the rock than in our previous trials … We’ve done lots of lab work, but now is the true test of whether the product will work underground or not.”
If successful, Graham says the finished product would have the robot mounted on the carrier MTI is designing. A worker would drive it to the appropriate spot underground, hit a green button, and then leave the area.
“The robot will sense when the person is gone, and then start up, do a scan of the (area), figure out where everything is, and spray appropriately,” he said. “Then it will turn on a little light, telling everybody that it’s done, and then someone will come back in and move it to the next place.”
Testing at the underground facility will begin within the next month. The compound will be sprayed on a dozen spots on the wall, then pulled off, to see, among other things, how well it clings to the rock and how it responds to pressure.
“We have to try and duplicate the conditions of mining at depth through the pull-testing.”
Robert Lipic Jr., MTI’s general manager, said the company is pleased to be involved with the project. He said MTI opened the underground testing area about a year and a half ago to test its own products, but is open to working with groups like CAMIRO.
“The initial vision was to have a place to test our own products,” he said. “But we’ve partnered with a number of suppliers. Explosives companies have come here, to do their own testing. And it has just gone on from there.”
Other possibilities include partnering with the education sector to help train miners and other underground specialists who need exposure to conditions underground, but are having trouble getting underground for training in a working mine. The MTI facility makes that easy, he said.
“You just walk down, and you’re here,” Lipic said.
The company is expanding the existing facility, adding shops, smaller drifts, as well as a separate area, so more than one type of training or testing can take place at the same time.
“We understand that there’s one similar facility like this in Europe, but there’s no other like it in North America.”