Over the past fifteen years, horizontal drilling in coal seams for advance degasification has become an established practice in the United States of America._x000D_
Consolidation Coal Company pioneered the development of the horizontal drilling system and licensed the technology in the U.S. A. and to Du Pont (Australia) for commercial production. This paper discusses the most recent developments in the equipment design, especially the borehole telemetry system, known as the Downhole Drill Monitor (DDM).