Abstract: A method and device for sensing hole parameters while drilling a borehole, and transmitting the sensed data to a remote receiver. Data are transmitted in digital format as a series of audible binary pulses generated by a solenoid acoustically coupled to the drill pipe. In a preferred embodiment, data transmission occurs automatically during periods of drilling inactivity.

Abstract: A device for placement between a rotary drill motor and a drill rod for use in pumping instruments down the drill rod. The device has pressure seals at each end and an opening for an instrument cable which slides through the opening as the instruments are pumped down the drill rod.

Abstract: A drilling fluid circulation system for containing drilling cuttings, gas and drilling fluid in a closed loop. The system includes a separator having two sealed compartments, one for settling out drilling cuttings and one for holding clean drilling fluid. A fine solids separator is provided between the two compartments, and a gas exhaust line for conducting gas released from the returning drilling fluid is provided to conduct the produced gas to a safe location away from the working area. A solids discharge device is provided for removing settled drilling cuttings.