Published at FC Gas Intelligence, Nov. 3, 2014
LNG is receiving increasing attention in the mining sector due to its price advantages over diesel fuel. Large mining operations can reduce their overall operating costs significantly by converting mine haul trucks to LNG. Diesel fuel generally costs between $3.50 and $4 per gallon while the equivalent amount of LNG, in terms of British thermal units, is between $1 and $2. Diesel fuel costs have risen in recent years while natural gas prices have fallen and are expected to remain low.
Large mining trucks, trucks with greater than 100 tons of capacity, can consume between 150,000 and 400,000 gallons of diesel fuel annually and over two billion gallons of diesel fuel are consumed annually by the top ten mining companies. There are over 28,000 of these trucks in service around the world today, and there may be up to 40 trucks at a single mine. Most of these trucks operate in confined return-to-base rotation, making the logistics very favorable for the mining industry to convert their trucks to LNG.
Environmental considerations are also very important. The threat of increased rules on emissions have contributed significantly to manager’s decision making. Diesel emissions have been judged to be carcinogenic by international authorities while LNG is non-toxic and the cleanest fuel available, LNG has lower greenhouse gas emissions than diesel as well.
Price differentials are highest in parts of the Rocky Mountains which is an area of extensive gas production where wellhead prices are low, while diesel can command a premium for delivery to the mine. Natural gas can be delivered to the mine via pipeline and liquefied on site, or else transported by truck from a nearby producer.
In April, 2014 Wyoming Governor Mead issued a report endorsing the use of LNG in the state’s mining industry. “The Wyoming LNG Roadmap” analyzed the feasibility, costs and benefits of using natural gas to fuel the state’s high horsepower sectors. “This report shows there is potential for expansion of LNG use in Wyoming that can add value to our natural gas, be a sound business decision for Wyoming industries, and lead to job growth,” Governor Mead said.
There are a small number of vendors that have taken the lead in developing engine technology that can use LNG instead of diesel. New technology is needed because older natural gas engines did not provide the power or torque that was provided using diesel fuel. Modern engine designs have overcome these technical barriers and enable large heavy duty vehicles to maintain the performance they require in the mines.
Caterpillar is a world leader in heavy construction equipment and their 793, 795, and 797 mining trucks are among the biggest in the world. The 797F is capable of hauling up to 400 tons per load with its 4000 hp engine.
Caterpillar has been working with Westport Innovations to integrate their HPDI (High Pressure Direct Injection) technology into the Cat engines. HPDI introduces natural gas directly into the combustion chamber of the engine and utilizes a small amount of diesel fuel as the ignition source. HPDI maintains diesel engine performance and responsiveness while using 95% natural gas. HPDI is the leading technology for this class of heavy duty diesel engine that maximizes natural gas use while maintaining the horsepower, torque and other performance characteristics of a diesel engine.
Westport offers a full range of LNG solutions for a variety of applications including medium and heavy duty road vehicles, rail, equipment such as forklifts and power generators, as well as tanks and fueling infrastructure. Westport’s Jumpstart Mobile Refueling Station is a mobile tanker that carries 5,500 gallons of LNG and dispenses 30-50 gallons per minute, this equipment is a good solution for temporary refueling needs in places where permanent facilities are not available.
Caterpillar has struck an agreement with Shell to test LNG mining trucks at Shells oil sands operations near Fort McMurray in Alberta, Canada. Caterpillar will provide both new trucks with HPDI LNG engines as well as retrofit existing trucks from its fleet. Caterpillar will also provide refueling infrastructure.
“To succeed commercially in the future, we believe we have to be able to compete economically and environmentally; we believe that is what Canadians want,” said John Rhind, Shell’s vice-president, oil sands. “With heavy hauling being such a core part of our operation, success with this could make a real difference in our operations costs and emissions.”
GFS Corp is another technology provider who is actively retrofitting mining trucks for dual fuel diesel-LNG operations. The EVO-MT system for mine haul trucks is currently available and enables operations of 50% LNG – 50% diesel. GFS Corp offers conversion packages for the Caterpillar 777 and 793 trucks as well as the Komatsu 830 and 930 electric drive trucks.
On October 7, 2014 GFS Corp announced an order from Arch Coal to retrofit the Komatsu 930E haul trucks operating at Arch Coal’s Black Thunder Mine in Campbell County, Wyoming. This deal follows on a successful conversion of two trucks in early 2014 and will consist of converting nearly a quarter of Arch’s truck fleet at the mine.
“The construction of the LNG plant fits with ongoing efforts to control costs,” Alpha Natural Resources President Paul Vining said in a statement. “Switching the Alpha Coal West fleet to the combined use of LNG and diesel will also lead to more efficient operation and longer engine life for the trucks.” The project is expected to create 40 jobs during construction and between 10 and 15 positions once it is up and running.
GFS Corp has also been converting a fleet of 16 Caterpillar 793’s at Alpha Coal West’s Eagle Butte Mine near Gillette, Wyoming with the EVO-MT system. Alpha Coal West began testing the GFS Corp conversion technology at their nearby Belle Ayr Mine in 2012 and after 18 months of successful operation decided to go forward with the complete conversion and infrastructure investments.
In conjunction with these truck conversions at Eagle Butte Mine, Plum Energy LLC will construct an LNG plant at the mine to supply Alpha Coal West’s trucks. Plum Energy’s plant, scheduled to come online in March 2015, will be able to produce 28,500 gallons of LNG per day and also includes a refueling station capable of handling eight trucks simultaneously. Alpha Coal West’s demand for LNG is projected to be around 6,400 gallons a day and Plum Energy plans to sell the excess product to other companies in the area as they convert their equipment.