February 2011

Bigger not always better

Technologies that integrate mine and mill can make marginal hard-rock mines profitable

By Peter Caulfield

The sensor system can be used in shovels, belts and sorters to detect ore from waste before sending it to the mill | Photo by Andrew Csinger, MineSense Technologies

In the 1980s, Toyota revolutionized its automobile production by adopting the principle of lean manufacturing. The practice assumes that all expenditure of resources should be focused on creating value for the end customer. Anything else is considered wasteful and should be eliminated. In its simplest terms, lean manufacturing means getting more done with less.

As a graduate student in mining engineering at the University of British Columbia eight years ago, Andrew Bamber adapted this idea and developed the concept of “lean mining.” The objective is to help reduce waste, excess plant capacity and re-work, which is caused by misallocating ore and waste. “Large-scale mining only dilutes inefficiencies by spreading them out over a large operation,” explains Bamber, CEO of MineSense Technologies Ltd. in Vancouver. “Lean mining, on the other hand, removes inefficiencies. The end results are smaller, more technologically intensive and productive mines, faster permitting, smaller footprint and higher returns.”

More efficient processing

The MineSense Solution, created by Bamber’s firm, is a practical outcome of the lean mining idea. Using sensors integrated into conventional mining process equipment (shovels, belts, sorters, etc.), it allows miners to detect and separate ore from waste before sending it to the mill. The sensor system can also recover valuable material that was previously cast aside as waste and send it to the mill for processing. “The reduction in waste rock benefits not only the mine, but also the mill and the smelter,” Bamber says. “This is a valuable difference. With these cost savings, mines that are marginally profitable or unprofitable using traditional methods can become profitable.”

“Sensing can also be used to quantitatively evaluate ore chemistry in the run-of-mine product and transmit that data to the mill,” he explains. “Such early knowledge of ore chemistry can be used to proactively adjust process parameters in downstream operations such as grinding, leaching and flotation, and thereby improve metal recoveries by one to two per cent.”

The MineSense Solution is a Canadian-made example of mine-mill integration. The term refers to methods of improving the interface between the mining operation and the surface mill. “Mine-mill integration can have a direct impact on the profitability of a mine of between 10 and 30 per cent,” says Professor Bern Klein, head of the Norman B. Keevil Institute of Mining Engineering at the University of British Columbia.

According to Bamber, there are a number of preconcentration technologies available, including sorting and separation by size and sorting by electromagnetic, optical, X-ray and nuclear means. By comparison, he says MineSense is a non-conventional preconcentration method. “What makes it different is the combination of ore sensing and the separation of ore from waste during and within the mining and material handling process.”

Less is more

The core of the MineSense technology is a proprietary signal generation and analysis system called high-frequency electromagnetic spectrometry (HFEMS). It can detect the type and quantity of mineralization in the ore. HFEMS helps miners decide whether to process, upgrade or dispose of it.

In laboratory and field testing for Xstrata and Vale, the prototype MineSense HFEMS sensor system demonstrated detection levels in ore particles as small as 15 mm of 0.1% nickel and 0.2% copper. MineSense has several customers in the nickel mining industry, both major and junior companies, and is engaged in projects in Canada as well as outside North America.

Bamber says that using the MineSense Solution will help reduce energy consumption, water use and greenhouse gas emissions, thus improving the sustainability of integrated mine, mill and smelter operations. He further adds that projected operational savings would enable the system to pay for itself in months rather than years.

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