Mining Publication: Comparison of Rotary and In-Hole Motor Techniques for Drilling Horizontal Boreholes in Coal
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 collected to serve as a base for comparing drilling procedures and operating costs. Findings indicate that drilling with an in-hole motor offers four advantages over rotary drilling; namely, an increase in drilling productivity, fewer worker-hours required, ease of maintaining vertical and horizontal bit trajectory, and less expensive drilling cost per foot of borehole.
Report of InvestigationsJanuary - 1985
NIOSHTIC2 Number: 10004416
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 8933, 1985 Jan; :1-31