A coalmine operation needed to lift a 50-tn conveyor counterweight during routine maintenance of the conveyor. The counterweight is housed in a take up tower at the end of the conveyor where it is suspended, using gravity to maintain tension to on the belt. To perform the scheduled conveyor maintenance, crews needed to lift the counterweight to release this tension and access the conveyor. A custom conveyor maintenance winch system from Thern Inc. provided an economical and reliable solution with the capacity to lift the large counterweight.

Thern built a 56,000-lb-capacity winch with a modified dual compartment drum able to facilitate two separate two-part rigging lines. Using two-part lines doubled the load lifting capacity of the winch to accommodate the 100,000-lb-capacity necessary to lift the counterweight. This relatively simple and straightforward modification provided an economical solution to achieve the power needed for the mine's application. The dual drum configuration, with two separate lines, provided redundancy.

To facilitate this two-part rigging, the winch was mounted above the counterweight at the top of the counterweight take up tower. For more convenient operation, the winch was equipped with a 50-ft pendant control to allow workers to control the winch remotely. Additionally, the winch's durable construction and epoxy finish meant that it could withstand the harsh environmental conditions at the top of the tower, minimizing maintenance time and cost.

For more information on Thern winches in bulk handling and mining applications, visit www.thern.com.