Comparison of Rotary and In-Hole Motor Techniques for Drilling Horizontal Boreholes in Coal

摘要

This Bureau of Mines report describes and compares the procedures, capital investments, and operating costs of rotary and in-hole motor drilling techniques used to drain methane gas from the Pittsburgh Coalbed in an underground mine located in southwestern Pennsylvania. A timestudy was conducted during the drilling of each of two boreholes, and the data were collated to serve as a base for comparing drilling procedures and operating costs.