CEMI to cast a wide net for deep mining research

The Sudbury-based Centre for Excellence in Mining Innovation (CEMI) plans to launch a Canada-wide request for proposals by late September for projects that would fall under its $46-million Ultra Deep Mining Network.

In January 2014, CEMI received a $15-million grant from the federal government's Business-led Networks of Centres of Excellence program to pursue research to make ultra-deep mining — deeper than 2.5 kilometres or roughly 8,000 feet — more efficient and productive.

As mines go deeper underground, technologies and processes that can improve costs and efficiencies can mean the difference between a profitable operation and one that goes out of business.

In January 2014, Samantha Espley, general manager of mines and mills technical services with Vale's Ontario operations, said the company wants to reach three kilometres in depth, or nearly 10,000 feet, at Sudbury's Creighton Mine within the next decade.

Creighton Mine is currently under its Phase 3 expansion, which includes the extension of the primary access ramp from 7,940 to 8,200 level and the creation of three main production levels to access additional ore bodies.

The federal funding for CEMI's Ultra Deep Mining Network was in addition to $17 million in cash contributions from large mining companies – especially Vale – and Sudbury area mining supply and services businesses. CEMI also received around $14 million in in-kind contributions for its Ultra Deep Mining Network, which included access to mining facilities and equipment for research and testing purposes.

“When we made the submission we had an initial group of supporters who had projects they wanted to work on,” said Douglas Morrison, CEMI's president and CEO.

Those initial stakeholders have already submitted projects in four key areas that impact ultra-deep mining: rock stress reduction; energy reduction; material transport and productivity; and improving human health for underground workers.

The request for proposals will open up roughly 75 per cent of the available funding to university researchers and mining companies across the country, that were not necessarily part of the initial group of supporters.

Morrison said advances in underground ventilation could arguably have the greatest impact on the profitability of ultra-deep mines.

“The ventilation cost is the single largest cost for any underground mine,” he said. “And to make that single cost larger has a very large impact on the overall viability of the mine.”

Mines are typically cooled through a natural heat exchange system – where air is cooled down at surface and pumped underground.

Because the air heats up as it is pumped deeper underground – the system is no longer effective beyond the 2.5-km point.

At that depth and beyond, mines need to introduce expensive systems to cool the air underground.

CEMI-funded researchers have already started to take cues from the past to develop more efficient systems for underground cooling.

“We're actually going back in time, and we're beginning to look at techniques that were used way back in the 1900s, before there was grid power and before there was ready access to fossil fuels,” Morrison said.

One such system was developed in Cobalt at the turn of the 20th century.

The ragged chutes technique, as it was called, used a small waterfall to produce compressed air that supplied oxygen to the area's mines.

Morrison said combining 100-year-old techniques with new technologies could lead to advancements in underground ventilation.

The advance rate for material transportation and productivity underground is another key component of the Ultra Deep Mining Network.

Underground drifts are currently expanded at a rate of around 3.5 metres per day, Morrison said.

“That's much slower than it used to be in the past,” he added.

CEMI wants to increase that rate of expansion to nine or 12 metres per day.

Ore tunnels are not built as quickly as they once were due to higher safety standards and the need for more ground support. Rock conditions are also poorer as mines go deeper underground, which complicates drift expansion.

Research to change the sequence of activities involved in underground mining – to better adapt to specific conditions – is expected to make the process more efficient, Morrison said.

The deeper a mine, the greater the physical stress on the surrounding rock.
Rock stress risk reduction – with new techniques to support underground tunnels, will help make mines safer, and more productive as they go deeper.

The final research component for the Ultra Deep Mining Network, Morrison said, is on the toll mining takes on workers, and how to ensure an aging mining workforce – where a large number of miners are over 50 – stays healthy.

Morrison said more monitoring of basic health signs, such as a worker's pulse and body temperature, is necessary.

Mines also need to do a better job determining miners' alertness and fatigue levels as they move deeper underground, and the margin for error shrinks.

Mining companies, and Sudbury's mining supply and services sector, will have big stakes in the research produced through the Ultra Deep Mining Network, Morrison said.

“We can't actually come up with a successful program unless they (mining companies) are involved in what we do,” he said.