The present invention relates to a wire saw excavation apparatus that is installed on a plurality of entry holes, where the plurality of entry holes are drilled according to a cutting section of a target surface of rock to be excavated so that the target surface is excavated by using wire saws. The wire saw excavation apparatus mounts N number of pulleys on one entry arm to cut the rock in N number of directions all at once.

The present invention relates to a wire saw excavation apparatus that is installed on a plurality of entry holes drilled according to a cutting section of a target surface of rock to be excavated so that the target surface is excavated by using wire saws, and more particularly, to a wire saw excavation apparatus that mounts N pulleys on one entry arm to cut the rock in N directions all at once, thereby remarkably improving the work efficiency.

Several embodiments of a drive pin retention system for mining chains comprise a drive pin, dowel pin, and retainer, wherein the dowel pin is fitted through the holes of a retainer aligned with the holes of the dowel pin and pressed with force so that the tolerance between the dowel pin and retainer is very close. In one embodiment, the retainer is tack welded and then the dowel pin is tack welded to further increase the tolerance and prevent loosening or movement of the retainer due to vibration.

Several embodiments of a drive pin retention system for mining chains comprise a drive pin, dowel pin, and retainer, wherein the dowel pin is fitted through the holes of a retainer aligned with the holes of the dowel pin and pressed with force so that the tolerance between the dowel pin and retainer is very close. In one embodiment, the retainer is tack welded and then the dowel pin is tack welded to further increase the tolerance and prevent loosening or movement of the retainer due to vibration.

An improved drive pin retention system for mining chains is disclosed, including several embodiments. The drive pin retention system further decreases the chance that the chain can break due to sheared dowel pins.

An improved drive pin retention system for mining chains is disclosed, including several embodiments. The drive pin retention system further decreases the chance that the chain can break due to sheared dowel pins.

An improved drive pin retention system for mining chains is disclosed, including several embodiments. The drive pin retention system further decreases the chance that the chain can break due to sheared dowel pins.

An improved drive pin retention system for mining chains is disclosed, including several embodiments. The drive pin retention system further decreases the chance that the chain can break due to sheared dowel pins.