Dig, Carry and Dump
In Bunlow, West Virginia, at the headwaters of East Plain Lake, Carl Hazelett takes one last sip of coffee as he pulls his truck up to the office. For Hazelett, surface operations manager at Pen Coal’s Kiah Creek mine, another full day of overseeing coal-mining operations begins before the sun peeks over the mountaintops.
Pen Coal started its mining operations in West Virginia late in 1988. Since then, Pen’s operation has grown to include four mines — two underground mines, another surface mine, and Kiah Creek. Hazelett came to Kiah Creek in 1996, but has been mining coal for more than 20 years.
From his time in the industry, Hazelett has learned some very important lessons — machines that get the job done efficiently are a must and productivity is the key to success in coal mining.
Komatsu Blade — Bigger is Better
“In the late 1980’s, I believed the industry would see a big increase in the number of draglines used to move large amounts of coal,” Hazelett says. “This did happen, but not in all mines. For smaller operations like ours, large blade dozers were substituted for draglines. Dozers produce more effectively in mines like ours because they take up less space, are easier to maneuver and the move from point A to point B is quicker.”
When Komatsu Mining Systems introduced its D575A Super Dozer in 1996, it defined the company’s commitment to provide the most productive mining dozers the industry had ever seen. Since its inception, the Komatsu D575 dozer — with its patented 90-yd.³ Super Dozer blade — has helped change the face of mining. With such large capacity, the blade offers 15 percent more productivity than a same size standard blade. Operators recognize up to 30 percent more productivity in uphill pushes as well. A full range of automated backward and forward movement through three positions — dig, carry and dump enable operators to speed their cycles and move additional material on every shift.
Hazelett explains what D575 blades do to aid production at Kiah Creek, “the D575’s blade carries material instead of pushing or rolling it. It increases the machine’s weight, giving it the mass to move more material. Consequently, we cut down on the number of passes needed. There are no other machines on the market that can meet the production output of the D575.”
The blade design also allows the operator to position it at the desired level for optimum digging action and, once the cut has been made, continue to adjust blade position as needed. When the carry cycle begins, a lock-up torque converter automatically engages, providing increased power to ground and more pushes per shift.
When the dump cycle is complete, the Super Dozer Blade feature allows the operator to return the blade from a dumping position to a digging position by automating the pitching action.
Maintaining High Productivity
Kiah Creek is a 24-hour, 6-days-a-week operation. Annually, thousands of tons of coal need to be blasted, pushed, loaded and trucked. One major factor in achieving such high productivity levels is an operator who is comfortable in his surroundings. With shifts exceeding 10 hours, it is imperative that cab comfort be a high priority. The D575As at Kiah Creek provide the needed comfort. Easy controls, superior visibility, and a comfortable suspension seat help make the rigors of dozer operation in a mine a lot more bearable. A standard air conditioner/heater also add to operator comfort.
“We run at about 96 percent uptime with our dozers,” Hazelett notes. “That’s a lot of time to spend in a dozer. Our success depends on the people we have in our machines and if there is little room, if controls are hard to reach or if it is too hot/cold, it can be almost unbearable for that operator. Obviously, we can’t meet our goals if we don’t provide good operating conditions.”
Hazelett notes that the production numbers for the D575’s average 750 yards per scheduled operating hour — double the numbers Kiah Creek realized before adding the Komatsu dozers. “Before adding the D575’s, we were forced to haul 60 percent of raw material and push only 40 percent. With the two dozers, we push 56 percent and haul only 44 percent. The machines have changed our traditional mining operations and, in the process, made us far more productive.”
In addition, Kiah Creek’s production increases have occurred without adding to its workforce. “The D575s have increased yards per man hour while reducing the cost of total yards moved,” Hazelett notes. “We are able to move half of our monthly production with the four operators that run the Komatsu’s. Our other 16 operators move the rest. That best describes what a large blade dozer can do in the right application.”
Torque Converter Lockup
Another major feature of the dozers that assists production is Komatsu’s exclusive automatic torque converter lockup system. By automatically engaging when load size and terrain permit, the system locks and adds power to the ground allowing the operator to get through the push.
"It also helps the operator stay focused once the blade is loaded because it automatically locks up — it is one less thing he needs to worry about.” Hazelett explains. “The automatic torque converter lockup also cuts fuel consumption.”
According to Komatsu, a standard torque converter affords an operator approximately 85 percent power efficiency. When the Komatsu torque converter lock-up engages, that same operator will notice about 98 percent power efficiency, thus significantly greater productivity. This feature significantly decreases operator cycle time and, most importantly, cost per yard.
Tough, Smooth Machines
The D575s at Kiah Creek are only down 4 percent of the time, Hazelett observes. Most impressive about the number is the fact that the undercarriage is included in it. It is a fact that dozers are parts eaters. They are pushed to the limit on every pass as the operator navigates the rough terrain. At Kiah Creek, the D575 undercarriages are averaging 6000 hours before replacement.
“In our business, putting 6000 hours on an undercarriage is pretty unique,” Hazelet says. “For us to get an average of 6000 hours is even more amazing. We have been tickled to death with the time we get on them — they just continue to crank.”
The dozers stability also provides an advantage to the operators. “We are making pushes that range anywhere from 200 to 800 ft.,” Hazelett says. “We are also making cuts as high as 170 ft. That means a great deal of uphill and downhill travel, in addition to straight pushes. Machines that can handle everything we throw at them is a big plus. More importantly, the fact that they stay on course and eliminate counter-steering allows our operators to concentrate on their job and not on factors that could hinder production. Simply put, they are great machines that have made our job easier while making us more productive.”
Komatsu’s D575A Super Dozer certainly plays many roles in a coal mine and the company’s goal of setting the standard for moving material quickly, safely and productively has been met. The future of Komatsu mining dozers is even more exciting as new technologies come to the forefront. As for Kiah Creek, Hazelett admits he is keeping his eye on what Komatsu will do in the future. “I think it is safe to say that, if we look to increase our large blade dozer fleet, Rish Equipment (Pen’s Komatsu dealer) will certainly be the first call we make.”