Published in the August 2006 American Longwall Magazine

Virginia-based Blue Ridge, established in 1952, is known as one of the country’s top sales and service outfits for diesel engines for underground mining equipment. Nunnally notes the company provides some of the most popular – Deutz, Isuzu and Mitsubishi – in the market in the category of engines with 250hp or less.

Nunnally said a mine can now choose diesel for just about any machine. “Any kind of application that could possibly be track, rail, rubber tired or skid mounted could possibly use a diesel engine,” he said, adding that these included generators, compressors, locomotives, rock dusters, scoops, personnel carriers and utility vehicles.

Environmental Protection Agency and Mine Safety and Health Administration guidelines dictate the boundaries of diesel use underground – including gaseous emissions, particulate levels, horsepower and ventilation requirements – but he said the advantages of the technology over options like electric and battery power often make up for that.

Mobility, especially in an age of lower seams and less-than-ideal environments, is one such plus: “It takes a whole lot less time to fill a tank full of fuel than it does to charge a battery.”

Also, diesel engines are self-contained, so there are no “umbilical cords” to be concerned about, Nunnally noted.

With diesel technology in recent years, there have been adjustments and improvements that have made the engines more efficient and more environmentally friendly.

“Cleanliness is probably the biggest change,” he said, mainly due to more stringent regulations. He added that the electronics within the engine’s design have also increased to include features such as monitoring chips and sensors.

Efficiency has also made its way into the design of diesel motors.

“[The] size is shrinking; you’re getting more horsepower out of a smaller engine.”

While Nunnally said the majority of the motors the company provides are below the 250hp threshold, the most popular diesel motor for underground mining use is around 60hp – which comes in at a compact 28in long x 18in wide x 28in high.

The company has established associations with some of the industry’s leaders to outfit their engine needs, including AL Lee, Damascus, DBT, J. H.

Fletcher, Johnson Industries and Rohmac Incorporated he said, and those relationships can often involve some level of consulting with Blue Ridge to determine the best engine choice for a piece of equipment.

“They’ll [clients] call and say, ‘We need a 70hp engine’ and we’ll recommend an engine to fit,” he said, and sometimes a transaction is more customer driven, with the end user requesting a specific brand and power for its needs.

While Nunnally and his staff often do not know where the engines they provide will eventually be used, he and Walter Stewart of Virginia-based personnel carrier manufacturer Damascus have been working on diesel engines for high elevations found in many of the operations of the western US that affect equipment transport and usage.

Most engines and equipment is made for a moderate elevation, up to 1000 feet above sea level, established by MSHA. With some mines in the eastern states reaching elevations around 3000ft while others in western states are higher than 7000ft, Stewart said there are issues to consider.

He and Nunnally have often worked in tandem to “de-rate” engines to meet MSHA requirements – essentially a process of setting back the motor’s fuel rack and adjusting the fuel mixture. Less oxygen at higher elevations dictates less fuel, and failure to de-rate an engine to the proper altitude causes unburned fuel and creates carbon monoxide, they noted.

Nunnally said while emissions are an ongoing issue with diesel use underground, its use is growing industry-wide because of efficiency, production and safety benefits. The improvements being made in the technology, most notably with cleanliness and electronics, will drive that movement.

States’ adoption of diesel engine rules and regulations will also keep the technology on a positive trend. In 2004, West Virginia was the last state to approve the use of diesel engines underground, and their stipulations are significantly more stringent than other states.

“The bottom line is: a safe working environment for the miners affected by the use of diesel engines underground is the number one priority,” he said.