Rapid development research picks up speed
Canopy proposed to allow simultaneous drilling, bolting and charging
A rapid development research project undertaken by the Centre for Excellence in Mining Innovation (CEMI) is itself making some rapid progress.
Xstrata Nickel has agreed to provide assistance and a Sudbury area mining supplier has been contracted to design and fabricate a steel canopy under which drilling, bolting and explosives loading could be performed simultaneously without having to move equipment in and out of the heading.
The objective is to achieve a single heading advance rate of 12 metres a day, versus the current average of three metres, according to CEMI program director Seppo Haapamaki.
Years ago, it was common practice for miners to install rebar behind a jumbo drilling under unprotected ground, “but as accidents occurred, legislation was introduced putting a stop to the practice,” said Haapamaki. “For the jumbo operator to work safely, he had to have the support above him, so what we’re looking at now is going back to the good old days, but with technology to keep the operator safe.”
The proposed canopy will be five metres wide, five metres high and 19 metres deep to accommodate a nine to 10-metre long jumbo and a bolter immediately behind it. The canopy will be in three sections to allow it to articulate around corners and manage inclines.
Three separate sections will also facilitate and simplify any repairs if part of the canopy is damaged. According to Haapamaki, the canopy will be designed and tested to withstand 50 tonnes of loose, “so if anyone is underneath the canopy and the back lets go, they’ll be protected.”
Skis or retractable wheels will be used to move the canopy through the drift, and cylinders in the legs will be used to lift it up against the back.
Screen would be draped over the rear part of the canopy, where a tubular design will provide access for bolting.
Installation of ground support will take four or five hours, while the jumbo will take approximately two hours to drill, leaving two or three hours of idle time at the face, noted Harvey Parsons, another CEMI R&D program director and former chief engineer at Vale’s Creighton Mine.
“The jumbo can’t get out because there’s a bolter behind it, so the question is, can we use the jumbo for something else? Instead of waiting to take everything out and bring in another machine to load the holes, we’re proposing to adapt the third boom of a jumbo to load the holes during those two or three hours,” said Parsons.
Once ground support is installed and the holes are loaded, crews would move the canopy five or six metres away from the face to take out the round.
The use of emulsion rather than anfo is proposed for better contour control and to limit damage to the canopy and other services. Mucking technology will also have to change, said Parsons.
“Normally, mucking out is a batch process. You bring in a scooptram, pick up a bucket, haul it out, put it in a truck, come back and pick up another bucket. The objective is to get 100 per cent utilization of the face, so instead of a batch process, we need to come up with a piece of equipment that will allow for continuous mucking – either a conveyor, a rail-veyor, or a slurry piping system. We’re aiming for an equipment solution that can muck out in an hour.”
The canopy is expected to be ready for testing in four to six months, but the entire project, including the development of loading and mucking solutions will take several years.
“The one thing we have to do is get buy-in from the miners themselves,” said Haapamaki. “We want to get them involved at a fairly early stage to observe the testing and provide us with feedback.”
CEMI is also seeking buy-in from mining companies interested in supporting the research and will collaborate with other research organizations, mining suppliers and the Ontario Ministry of Labour to move the project forward.
The end goal, one which any underground mining operation can relate to, “is to increase the value of the material coming to surface. That’s what it’s all about,” said Parsons. “And if continuous mining can work in development, there’s no reason why it can’t be adaptable to production in a stope or a drawpoint.”