Largest producer of coal from underground mines in North America Consol Energy has placed orders for Caterpillar (CAT) longwall equipment, including more than 1 100 roof supports, worth $300-million. Delivery of the equipment started at the end of 2012 and will be completed in mid-2013.

In addition to roof supports, the four northern Appalachia mines – Bailey, Bailey Mine Extension (BMX), Robinson Run and Shoemaker – will get two armoured face conveyors, a shearer and three shield haulers. Consol is also equipping all four longwall systems with the CAT PMC-R electro- hydraulic control system for advanced automation as well as the CAT Detect Personnel, a personnel proximity detection system designed to enhance the safety of miners working around longwall systems.

In addition to the four mines receiving complete roof support systems from the Caterpillar facilities in Lünen, Germany, Consol’s McElroy mine will receive 60 roof supports to be used in extending the longwall face. Also, the Enlow Fork mine and the Shoemaker mine will upgrade to CAT PMC-R electrohydraulic control systems. After the retrofit of the old systems, Consol will operate a total of nine faces with PMC-R control systems. Of these, Consol will equip seven longwalls with the CAT Detect Personnel. Consol plans to make the use of CAT PMC-R controls standard in all its mines.

Mining the Pittsburgh 8 Seam
All the Consol mines receiving new equipment are mining the Pittsburgh 8 Coal Seam in south-western Pennsylvania and northern West Virginia, in the US. The Bailey and BMX mines, in Pennsylvania, will take delivery of 25.4 t roof supports with 380-mm-diameter props. The roof supports will operate on 1 750 mm centres and have an operating range of 1.295 m to 2.743 m. The Shoemaker and Robinson Run mines, in West Virginia, will operate 22.9 t roof supports with 345-mm-diameter props, with an operating range of 1.245 m to 2.743 m. All four mines will have identical face-end supports weighing 29.8 t, with an operating range of 1.295 m to 3.048 m.

Monitoring and Automation
The PMC-R electrohydraulic control system operating each longwall has sufficient computing power and data transfer speed to allow the addition of remote and semi- autonomous face operation. All roof supports are also prepared for the retrofit installation of the CAT MotionMonitor system, which employs several strategically placed inclino- meters that supply angularity data to the PMC-R system. With this data, the system can calculate the geometric attitude of each roof support. This information is needed to steer the face when operating in semi- autonomous or autonomous mode.

By monitoring the angular rate of change during times when the roof support has not been given a command to move, the system also can be used to detect unexpected movement of roof supports as well as roof convergence. The detection of unexpected movements helps in preventing equipment collisions and enhances prediction of impending geologic activity, such as rockbursts.

All roof supports will be equipped with the CAT Detect Personnel, part of the detect capability set of the CAT MineStar system. The system has the ability to accurately and reliably identify the presence of personnel and to transmit this information in real time to the local roof support control system to allow appropriate action to be taken to prevent injury.

Face Conveyors
The BMX mine will be supplied with two complete 470-m-long PF6 armoured face conveyor (AFC) systems equipped with P-65 Controlled Start Transmissions (CSTs) and KP-65 CST AFC drives with installed power of 3 × 1200 kW. These PF6 AFCs have a width of 1.142 m and can convey a maximum of 3 500 t/h of coal.

The PF6 design separates wear parts from structural parts. The combination of welded and cast pans achieves an expected three-fold increase in the life of structural plates. The replaceable top race is made of extremely hard, wear-resistant materials while the supporting structural parts are made of high-strength steels.

Robot welders attach the top race with standard welds that can be removed automati- cally for trough replacement. The innovative design, combined with precision engineering and smooth rolled steel surfaces, results in a substantial reduction of friction and wear, making the PF6 ideal for ultralong panels.