A coal mine located in southern West Virginia (USA) recently set another world record for daily low-seam coal production using a Cat® automated longwall plow system. In a 24-hour period on April 10 and 11, 2014 the Pinnacle Mine longwall produced 35,724 tons (32 411 tonnes) from the Virginia Pocahontas No. 3 Seam, in a seam height of just 56 inches (1.42 meters) along the 980-foot (298-meter) longwall face.
The Pinnacle Mine, located near the town of Pineville and owned by Cliffs Natural Resources Inc., an international mining and resource company, operates a Cat Gleithobel GH1600 Longwall Plow System. A previous record was set by this system at Pinnacle in August, 2012 when 32,430 tons (29,423 tonnes) were mined in a 24-hour period.
The new record was set by the same system, mining its second panel after a comprehensive rebuild was performed by Carter Machinery, the Cat Dealer in that area. The rebuild encompassed a complete rebuild of the headgate and tailgate armored face conveyor (AFC) drive, the headgate and tailgate special AFC pans, the stageloader drives and return end, the complete crusher and all gearboxes for the plow, AFC and stageloader. Carter acquired the rights to sales and aftermarket support associated with the former Bucyrus mining products, both surface and underground, in 2013.
“Supporting and rebuilding a longwall plow system was a new experience for the Carter service team,” said Chris Curfman, President of Caterpillar Global Mining Sales and Support Division. “However, given the record production results attained by the rebuilt system at Pinnacle, it’s obvious that they are up to the challenge of supporting the underground product lines at the same high standards and quality level that they have been delivering for many years on the traditional Cat surface mining products.”
Tom Bluth, President of Caterpillar Global Mining Products Division, said, “Caterpillar congratulates the Pinnacle team for this great achievement. Without their efforts and dedication this record would not have been possible. To safely deliver that kind of output from such a thin seam is remarkable. We have been privileged to work alongside their team to demonstrate the capabilities of Cat longwall mining technology. ”
The Cat automated longwall plow system at Pinnacle is currently the only one operating in the United States. The longwall system has 2 x 800/400 horsepower (600/300 kW) of installed power for the plow with two operating speeds of 395/197 feet per minute (2.0/1.0 meters per second) and 2 x 800 horsepower (600 kW) installed power for the armored face conveyor (AFC). Each roof support in the system has a total leg cylinder capacity of 715 tons (649 tonnes) with an operating height range of 35 to 77.5 inches (890 to 1,968 millimeters) and is equipped with its own PMC-R electrohydraulic roof support control. Other units from the Cat Programmable Mining Control family are used for overall face automation and visualization, as well as for drive control. The longwall is equipped with a PF4/1132 face conveyor, a PF4/1542 stageloader and a SB0815 V-belt crusher with a 300-horsepower (225-kW) motor.
To set the new record the cutting depth was calibrated to cut 140 millimeters at a speed of 395 feet per minute (2.0 meters per second) when traveling towards the headgate and 250 millimeters traveling at 197 feet per minute (1.0 meter per second) to the tailgate. The depths and speeds are customizable and were selected to optimize loading of the face conveyor.
Enhancing safety and production
From a safety perspective, the Cat longwall plow system holds a significant advantage. For example, by using the Command for longwall capability set from Cat MineStar® System, the plow is operated remotely with no personnel required at the production face. As a result, there is no operator exposure to airborne dust, falling rocks or moving equipment, which is particularly important in such a limited work space.
In addition to enhancing safety, the Cat longwall plow can be a more productive choice, especially in thin seams. For example, the compact design of the plow system operating at Pinnacle allows it to work efficiently in a vertical space as low as 46 inches (1.17 meters). Other designs are available that enable the plow system to mine seams as low as 39 inches (1.0 meter). With its high-powered drives, high-speed plow, high advancing forces and electronically controlled cutting depths, the system can extract large volumes of coal quickly and economically, regardless of seam hardness and geologic composition.
“Numerous production records have been set with Cat products, in this case demonstrating the superior production capabilities of our longwall plow systems in thinner seams. Our plow systems have been operating successfully for many years in mines around the world,” said Uli Paschedag, Global Product Manager of underground products for Caterpillar Global Mining. “After learning of this achievement, my hope is that even more mining companies with low-seam reserves will take a closer look at Cat automated longwall plow systems and will see our systems as efficient, profitable and sustainable for recovering those reserves.”