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Overcoming the challenges associated with ultra-deep mining in northern Ontario.
TORONOTO, CANADA – Ontario is known for its long history in hard rock, underground metal extraction. Home to world-class gold and base metal deposits located deep underneath the earth’s surface, decades of mining means that those metals that are easily reached are now gone. Rather than shuttering their mines, companies in northern Ontario are working at depths of between 2 km and 3 km underground to extract high-grade material from previously inaccessible deposits.
Deep mining presents huge technical challenges. Heavy equipment must be modified to fit tight, confined spaces. Sinking a 2,500 m shaft requires stronger materials and vigilant safety protocols. Water management is critical, as is ventilation. Working conditions at nearly 3,000 m are hot, wet and cramped.
Cementation Canada, based in North Bay, Ontario, dealt with one of the world’s deepest mines at GlencoreXstrata’s Kidd project in Timmins. The Kidd copper-zinc mine is the deepest base metals mine in the world, and the company was tasked to design its No. 4 shaft. “It was a winze where the collar started at 4,700 ft (1,433 m) below surface,” explained Roy Slack, president of Cementation Canada. “Instead of constructing it incrementally, we built both simultaneously, which took a year off the project schedule.” By the time it was finished, the shaft bottom was 3,014 m below surface.
Remote operation
A large cluster of service companies has grown in northern Ontario to address the challenges associated with deep mining. The industry’s epicenter is Sudbury, nearly 400 km north of Toronto, where nearly one in five people are directly employed in the mining supply and services sector. (In a nod to the city’s long mining history, locals are more likely to refer to Vale as Inco and GlencoreXstrata as Falconbridge.)
Most of the service and engineering companies in northern Ontario have management who worked at either of the two mining giants. One such company is Penguin Automated Systems Inc., whose founder, Dr. Greg Baiden, was formerly responsible for corporate mining research at Inco. His work at Penguin ASI involves developing remote-controlled technology to access areas that are unsafe for humans. In 2009, the company was asked to survey an underground mine in Timmins (north of Sudbury) that had been closed due to a ground fall from a blast. Penguin recently received a CAD$1 million grant from the federal government to develop a new robotic system that will be able to enter confined spaces to load explosives for remote detonation.
A more common problem in underground mining is a blocked borehole. If the blockage is located at a significant depth, it can be a tedious and expensive process to address the problem. Minewise, a Sudbury-based company developed a video inspection service that consists of a camera attached to a reel that can reach up to 4,500 ft (1,370 m). The camera transmits images of the shaft to the surface to determine the nature of the blockage.
Ventilation
The government of Ontario has been paying particular attention to air quality systems in underground mines. The Ontario Ministry of Labour issued new requirements to better protect mine workers from exposure to diesel particulate matter (DPM), a component of diesel exhaust that has been deemed as a known carcinogen by the International Agency for Cancer Research.
A number of companies in northern Ontario are looking at ways to improve air quality in underground mines through systems that allow workers to monitor dust loading, airflow temperature and relative humidity for worker heat stress. Maestro Mine Ventilation developed a system called Vigilante AQS™ (or Air Quality System) that measures different parameters such as dust loading on haulage ramps and gas detection technology. Mine managers are then able to access that data in real time.
Research
By virtue of its strategic location and history in underground mining, Sudbury has developed a strong research network to better understand the intricacies of deep mines. Founded in 1995, the Northern Centre for Advanced Technology (NORCAT) is a private, non-profit training and development facility that owns and operates a former Falconbridge mine that they have converted into an underground training centre. The mine provides a realistic setting for mining companies to design, prototype and test equipment.
In addition to NORCAT, the Centre of Excellence in Mining Innovation (CEMI) is a non-profit organization with long ties to the mining industry in northern Ontario. The centre was recently awarded a $15 million grant from the federal government for its Ultra Deep Mining Network that will help to address the challenges of mining below 2.5 km underground. The specific research initiatives will focus on areas such as rock stability, energy reduction, material transport and cooling systems.
As minerals and metals continue to be found deeper under the earth’s surface, new challenges will arise. Health and safety is the primary factor in deciding whether it is possible to extract material at such depths, as is the economics of deep mining. Despite the challenges, there are a cluster of companies and organizations in northern Ontario who are dedicated to unlocking value from the deep mines of the future.
This article was written as part of GBR’s research on the mining industry of Ontario, to be published in Engineering and Mining Journal. To participate in this report, please contact Gabrielle Morin at gmorin@gbreports.com.