Skills & Knowledge
OMA event elicits novel mining solutions
Laurentian University mining engineering students clean up
Mining engineering teams from Laurentian University finished first and second in the Ontario Mining Association’s second annual MINED Open Invitation Challenge May 17 at the Art Gallery of Ontario in Toronto.
Teams from the University of Toronto’s Lassonde Institute of Mining, Queen’s University’s Robert Buchan Department of Mining and Laurentian University’s Bharti School of Mining were invited to participate in the event. Three finalists – two teams from Laurentian and one from Queen’s – presented their solutions to a panel of judges and an audience of industry leaders in a Dragon’s Den-style showdown.
The teams were presented with a case study and asked to come up with a novel solution to economically justify mining a new, low-grade orebody at depth in an existing mine.
Cash prizes of $15,000, $10,000 and $5,000 were up for grabs for the first, second and third place finishers, respectively, along with an additional audience choice prize of $5,000.
The first place team made up of Liam Anderson, Anthony Farrugia and Michael Janakaraj proposed an innovative, in-situ biomining solution to develop the new orebody.
“The two other teams came up with a solution that involved moving material, but our team decided it wouldn’t be feasible to move material because it would require development to increase the capacity of the shaft, so we decided to only remove the actual metal from the ore,” said Farrugia.
The biomining solution eliminated blasting and mucking from the traditional mining cycle and greatly reduced or eliminated the need for backfill.
The solution involves drilling the stopes using the traditional fan pattern and fracturing the rock along the grain boundaries using Swiss-based Selfrag’s technology “to shock the stope with electricity.”
The high voltage electricity delivered via electrodes inserted into the drillholes produces a network of micro-cracks along grain boundaries, creating pathways for the introduction of a leachate containing bacteria and a small amount of sulphuric acid for priming.
Once sealed, the stope functions as a vessel or tank, allowing the leachate to dissolve the minerals. The team estimated it would take approximately 100 days for an 80 per cent recovery.
Suspended in liquid, the freed minerals would then be pumped to surface and the regenerated leachate returned underground in what would be a closed loop process.
With 90 per cent of the rock still in place and stability not an issue, there may not even be a need for backfill.
Farrugia and his teammates won the $15,000 first prize as well as the audience choice prize of a further $5,000.
Shivam Sharma, the second place finisher, proposed a decentralized crushing solution using impact crushers.
“Instead of having a large excavation to house one big crusher, you’d have a series of smaller crushers at different levels,” said Sharma.
A scoop operator would simply dump the crushed ore into a nearby borehole for delivery to the bottom of the mine, where it would be conveyed to the skip and hoisted to surface.
“I talk to scoop operators and they tell me they absolutely hate loading trucks because their bonus isn’t based on how many trucks they load. It’s based on how many tonnes they draw, so if you’re spending four or five hours per shift just loading trucks, that’s five hours you aren’t drawing tonnes,” said Sharma, who is finishing up a 16-month co-op at Tahoe Resources’ Timmins West Mine.
The decentralized crushing solution eliminates the haulage time to a remuck pile and the rehandling of the remuck to load trucks.
“Drilling is cheap. Trucking is enormously expensive,” said Sharma, justifying the cost of the 12 to 30-inch boreholes required for the solution.
Once a stope has been mined out, the crusher would simply be relocated, which would require it to be configured for mobility.
Sharma cited the elimination of trucks and a big crusher as well as the excavations required for them as benefits over and above the increased productivity.
Finishing third was a Queen’s University team comprised of Curtis Dykstra, James Fortune, Samuel Grant, Ryan Mahon and Jeff Wright.
The Queen’s team also strove to reduce loading travel and cycle time by using a constructible conveyor belt system made up of one-metre lengths that could be easily assembled and disassembled using mechanical linkages and electrically induced magnets.
Instead of transporting the ore to a remuck pile, a loader would simply dump onto the nearby conveyor. The material would be conveyed to a remuck pile, dumped and then loaded onto trucks.
The team chose not to eliminate trucks entirely, said Fortune, the spokesman for the team, because, “the mining industry tends to resist major changes. We thought of our solution as baby steps that could over time eliminate the use of trucks.”
The proposed constructible conveyor belt system, which would have to be designed and developed, could also be used in reverse for the transport of backfill, said Fortune.
The judges for the competition were Jon Gill, a director of Kirkland Lake Gold, Patrick Merrin, senior vice-president of Goldcorp, and Peter Xavier, vice-president of Glencore’s Sudbury Integrated Nickel Operations.