Longwall roof supports

Louise Davis

CNX Coal Resources LP has placed an order for 285 Cat longwall roof supports destined for use in the Enlow Fork Mine in southwestern Pennsylvania, USA.

The mine is one of three in the complex, which produced 20.7 million tonnes (22.8 million tons) in 2015, making it the largest underground coal mining operation in North America. Enlow Fork currently operates two longwalls and seven continuous miner units and produced 8.2 million tonnes (9.0 million tons) last year from the Pittsburgh 8 Coal Seam.

Working with the Cat dealer in the area, CB Mining, Caterpillar will supply 274 face roof supports and 11 gate end roof supports. The shields will be built at the Caterpillar facilities in Lünen, Germany, and will be delivered in the first half of 2017.

CNX Coal Resources also is equipping the longwall with the Cat PMC-R electro-hydraulic control system for advanced automation.

The system has sufficient computing power and data transfer speed to allow adding remote and semi-autonomous face operation. The company currently operates five longwalls at the Enlow Fork, Bailey and Harvey mines, and all use the Cat PMC-R control system.

The roof supports have an expected service life of 60,000 cycles and will operate on 1750-mm centers, with a shield density of 846 kN/m2. The face supports will have an operating range of 1295 to 2743 mm, and gate end supports will have an operating range up to 3048mm.

CNX Coal Resources also will be using Cat Detect Personnel for Longwall, a personnel proximity detection system designed to enhance the safety of workers around longwall systems.

Using radio frequency identification (RFID) tags worn by personnel and detection units mounted on the longwall roof supports, the system accurately and reliably identifies the presence of people on a longwall and transmits personnel location information to the longwall automation system.

The control system then takes appropriate actions—such as inhibiting roof support movement and providing warning signals—when necessary to avoid potentially unsafe situations.

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