Shaft mines can get power without armor
A Pennsylvania coal operator has been able to install neoprene jacketed mine power feeder (MPF) cable in an airshaft without the use of expensive armored power cables. Armored cables traditionally have been favored in applications where the cable is dropped vertically because their galvanized metal shielding protects the cable as it is dragged across rough ground and stretched by its own weight as it is lowered into the hole. But armored cable poses some problems. It is as much as $20 per foot more expensive than MPF cable. Also, sinking armored cables is particularly difficult when space is limited because the cable must be laid out on the ground before it is lowered into the hole. The technique that allowed Pennsylvania Mines Corp. to install two 750-ft-long, 15-kv cables at is 400,000-tpy Tunnelton mine, near New Alexandria, Pa., was devised by J.H. Service Co.'s Indianola, Pa., branch office. The method involves feeding MPF cable from a spool on a truck equipped with special braking devices, over a steel drum that acts as a sheave, directly into a mine shaft or borehole. Robert C. Kadyk, a sales manager with J.H. Service, says that while this is not the first time standard MPF cable has been used in a borehole or shaft, the cables are not usually used in these cases because there were no dependable methods for holding the cable steady as it was lowered into the hole to keep it from abrading against the sides of the borehole or shaft. Also, dragging MPF cable through the woods invariably damages it. With its cable sinking method, J.H. Service vulcanizes stainless steel kellems grips into the cable about every 100 ft. The interval varies with the weight and diameter of the cable, depth of the hole, and length of the kellems grip. One twisted steel messenger wire is attached to each kellems grip to displace the weight of the cable as it takes its trip to the mine floor.
- OSTI ID:
- 6388308
- Journal Information:
- Coal Age; (United States), Vol. 89:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
ELECTRIC CABLES
DESIGN
ELECTRICAL INSULATION
MINE SHAFTS
UNDERGROUND MINING
CHEMICAL COMPOSITION
COAL MINING
DAMAGE
MATERIALS HANDLING
NEOPRENE
CABLES
CONDUCTOR DEVICES
ELASTOMERS
ELECTRICAL EQUIPMENT
EQUIPMENT
MINING
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
POLYMERS
SHAFT EXCAVATIONS
012000* - Coal
Lignite
& Peat- Mining
422000 - Engineering- Mining & Underground Engineering- (1980-)