June/July 2011

Exploring the limits

New challenges in extraction are driving suppliers to find new equipment and safety solutions

By Eavan Moore

Graphic courtesy of MDA

The minerals industry, driven by strong demand for mineral resources, is testing its limits and opening up new frontiers. Explorers, builders and operators are digging ever deeper to find new reserves, and venturing into territories previously considered unmineable, all while confronting the long wait times for equipment and taking care to guarantee the safety of its workforce.

Suppliers to the industry must work to keep up with these ambitions. Whether helping customers conserve their tight supplies and comply with regulations, or designing new tools for new conditions, suppliers are key to keeping mines operating in the face of unique challenges.

Treading lightly

Nowhere is the operator-supplier relationship more clear than in tire development. In this current boom cycle, demand for tires still exceeds production capacity. Tight supplies and the steep expense of replacing tires as the costs of raw materials rise give operators strong incentive to keep their tires in operating condition longer.

But it is still a struggle to make those tires last. Even the factors that seem straightforward — tire pressure, road conditions, truck loading — prove challenging to control. In response, industry and suppliers work closely to share their expertise.

Barry Rexroad, director of OTR (off the road) engineering and mining at Bridgestone Americas, says that the company engages in product development, technical service, training and an industry-leading tire-use tracking software, TreadStat® to ensure that the best products are getting the best use. “Bridgestone uses a technology called G-Hawk that combines GPS measurement along with a three-axis force measurement system to get real-time data on the forces and stresses that the tires see as a truck runs in the operation,” he says. “We can determine portions of the haul road or truck operation that could overstress the tires.”

Meanwhile, new products reflect research into the tread patterns and architectural details that hold up best in different applications. Bruce Besancon, director of marketing for Michelin earthmover tires, explains: “Any time Michelin puts out a new product, it’s always going to be on the basis that we want to increase the productivity. Our newest earthmover tire, the XDR2, runs cooler and has new features to lessen the impact from rock cuts and other outside influences.”

When tire supply was at critical levels between 2007 and 2009, says Bob Dirk, director of mine operations at Suncor Energy, the challenge was met jointly. “We took on a lot of improvement work and set the world record for tire life for three different sizes. Suncor’s employees can take credit for half of those improvements, and I would give the tire manufacturers credit for the other half.”

A cleaner work site

The industry faces another challenge in the environmental impact of its standard equipment. When diesel fuel is burned, it generates a number of pollutants, including nitrogen oxides (NOx), which contribute to smog and acid rain, and diesel particulate matter (DPM), which has broad environmental effects while directly damaging human health.

In response, a number of jurisdictions have set progressively tighter limits on emissions levels. Diesel emissions, regulated in Canada since 2006, would see a further reduction starting in 2012 under amendments proposed by Environment Canada in accordance with United States Environmental Protection Agency (EPA) guidelines. DPM would be reduced 50 to 95 per cent under these guidelines.

The success of these regulations rides on new engine technologies. Komatsu and Caterpillar are among those suppliers already offering machine models with emissions-reducing engine add-ons that meet the latest standards.

This year and next, Caterpillar will release several machines that meet the most stringent criteria defined by the EPA. Each machine will include some combination of several emissions-reducing elements. An NOx reduction system diverts and cools some engine exhaust gas, then returns it to the combustion chamber to inhibit NOx formation by lowering cylinder temperatures. A diesel oxidation catalyst breaks down pollutants, and a diesel particulate filter removes soot from the exhaust stream. The self-cleaning filter uses heat from the exhaust gas to burn off soot.

The more advanced technologies require ultra-low sulphur fuel, which is mandated in some countries but difficult to obtain in others. “Caterpillar will offer different configurations of machines for heavily regulated countries versus less regulated countries,” says spokesperson Mark Sprouls.

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