| 摘要 |
<p>A telescoping sub (50) for mining operations and the like. The telescoping sub (50) includes a rotor (94) portion couplable to the rotary head of a drilling rig, and a stator (74) portion that is couplable to a drill rod. The rotor (94) portion is slideably coupled to the stator (74) portion and is moveable with respect thereto between an extended position and a retracted position. With the telescoping sub (50) in the retracted position, the drilling rig is operated to drill to a first depth. The drilling rig is then operated to move the rotor (94) portion to the extended position, and the drilling rig is operated to drill to a second depth that is greater than the first depth.</p> |
