ABSTRACT
At present this is still problematical because of poorly developed drilling methods for horizontal boreholes, i.e. from the surface to a coal seam or within the coal seam itself.
Taking into account the severity of the problem, the results obtained during drilling operations associated with underground coal gasification are quite optimistic about developing methods to extract very fine coal and coal-derived products, by the year 2000.
2.2 TECHNOLOGICAL ADVANCES IN OPENCAST COAL MINING
