Diesel has long been the fuel of choice for the enormous haul trucks, dozers, shovels and other equipment that most mines use. Many industry leaders, however, are looking ahead to natural gas as an economically and environmentally friendlier source of energy for the colossal machines.
“LNG (liquefied natural gas) is a fuel source that has the potential to lower costs, significantly reduce emissions and improve environmental performance at our operations,” said Teck Resources Ltd. President and CEO Don Lindsay. “We are committed to minimizing our own carbon footprint, while at the same time continuing to provide the mining products that are essential to building a modern, low-carbon society.”
To this end, Teck is piloting a project that is using a mixture of LNG and diesel to fuel six haul trucks at its Fording River steelmaking coal operation in southeastern British Columbia.

 In Alaska, LNG is one of the alternatives proposed to power haul trucks in a recently completed draft environmental impact statement for the Donlin Gold project, as a means of reducing the amount of diesel that would be needed to barged to the large open-pit mine once it is built and begins production.

This would be another step towards Teck’s overall goal of reducing its greenhouse gas emissions by 450,000 metric tons per year by 2030. Since implementing this plan in 2011, the diversified miner has cut annual CHG output by about 170,000 metric tons.  “Like British Columbia, Teck is a global leader in finding innovative ways to reduce GHG emissions while continuing to create opportunity,” said B.C. Premier Christy Clark. “It’s a concrete example of the difference clean-burning LNG can make in the fight against climate change.”

FortisBC, which distributes natural gas in the western province, is supplying the fuel and is helping to finance the pilot.  “Teck is demonstrating leadership by adopting natural gas as a cleaner and more cost-effective fuel solution for their operations,” said FortisBC President and CEO Michael Mulcahy. “LNG, as a vehicle fuel source, provides both an economic and environmental benefit to industry in our province. Today’s announcement further builds on the diversity of the more than 400 natural gas-fueled vehicles in British Columbia.”  Teck plans to run the pilot until mid-2016, at which point it can evaluate the opportunity to implement the LNG-diesel technology across a wider section of its haul-truck fleet.

Once developed, the Donlin Gold Mine in Southwest Alaska will have a fleet of enormous haul trucks, an excess quantity of natural gas and a need to barge and store a year’s worth of diesel to the remote site during a 110-day window. This combination could make the planned operation ideally suited for LNG-fueled haul trucks.  Donlin Gold LLC – equally owned by subsidiaries of Novagold Resources Inc. and Barrick Gold Corp. – has been keeping an eye on emerging technology.  Kurt Parkan, external affairs manager, Donlin Gold, told Mining News that the idea of LNG-fueled trucks was considered when the partnership developed the mine-plan, but without a surety that the technology would be available for commercial production, Donlin Gold could not build its preferred mine plan around the fledgling technology. Regulators in charge of issuing permits to develop the 40-million-ounce gold project also see natural gas as a potential source of fuel for the heavy haulers at Donlin.

According to the recently published draft EIS, LNG-fueled haul trucks could reduce the amount of diesel needed at the Donlin Gold operation under evaluation by 29 million gallons per year, or 68.5 percent less than the 42.3 million gallons that would be required to fuel conventional trucks at the proposed large open-pit gold mine.“At present, LNG-powered haul trucks are not currently in full commercial production,” the Corps observed in the draft EIS. The potential upside of LNG-fired trucks, however, was too compelling for the agency to completely ignore.  Fueling the trucks with natural gas would ease traffic on the Kuskokwim River, one of the primary concerns the Corps heard during an initial scoping period of the Donlin EIS process.  This alternative also would reduce the amount of fuel storage needed at the mine site and Bethel, a town at the mouth of the Kuskokwim River where the river barges would load diesel and other supplies and equipment delivered via ships.  “If it does come into commercial production, we will totally jump on top of that because it will allow us to take more diesel off the barges,” Parkan explained during a recent interview with Mining News.

To make the natural gas usable for haul trucks, a plant to convert the natural gas to LNG and tanks to store the liquefied gas would need to be built at Donlin. An investment and endeavor Donlin Gold believes would be worthwhile if the technology gets developed commercially.“The LNG plant that we would need at the project site is fairly simple and clearly, the costs associated with putting that in is compensated by the fuel-cost savings,” Parkan said.  Donlin Gold is keeping an eye on the pilot project being carried out by Teck and other developments that would move the emerging LNG-fueled haul truck technology into the mainstream.   “It is definitely a win-win, if it becomes commercially viable by the time we need it,” he said.

In addition to the tests being carried out by Teck, at least one company in the United States is increasing its fleet of LNG-fueled trucks and a number of heavy equipment manufacturers are developing natural gas engines for the heavy haulers.  GFS Corp. has developed conversion kits for a number of different makes and models of haul trucks.  Arch Coal has been steadily increasing the number of trucks at its Black Thunder Mine in Montana that are equipped with the GFS conversion kits.  Arch Coal converted its first batch of Komatsu trucks to the LNG-diesel mix in January 2014. This year, the company ordered conversion kits for 10 additional trucks.  In addition to two models of Komatsu, GFS Corp. has developed conversion kits for at least two Caterpillar haul-truck models.

“Of particular interest to many mining customers, and Caterpillar is the potential to leverage natural gas for reduced fuel costs and greenhouse gas emissions,” the company explains on its website. “The technology we are pursuing for large mining trucks offers substitution of diesel with natural gas, as well as lower greenhouse gas and criteria pollutant emissions when compared to today’s diesel engines. This technology in our fully integrated solution will be a key differentiator in the mining industry.”

Cummins is another company that is developing natural-gas-fueled trucks specifically to meet the growing demand from mining operations.  “The rapid expansion and abundance of natural gas in some areas of the world is driving a dramatic cost advantage of natural gas over diesel fuel, making natural gas a very economical fuel source for mine sites,” Cummins explains.  The company said it plans to announce the roll-out of its first batch of LNG-diesel engines especially tailored for mining applications in the near future.  The engines being developed by Cummins actively monitors the work load and adjusts the LNG-diesel ratio accordingly. They also could run on diesel alone. The company estimates that in typical operations roughly half the energy could be expected from natural gas, resulting in about 30 percent in fuel savings.