Drilling holes in rock strata in mines - involves flushing out drilled matter with fluid suspension continuously applied under pressure

摘要

Material arising from drilling is carried away from the drilled hole with an auxiliary medium, while the cutting edge is cooled. The process is used for making holes in layers of rock for explosive charges, anchors or injection, esp. in underground mining. The material is flushed out from the hole, by a suspension continuously introduced during drilling, which has a high fluidity for a brief period of time or bonded in the hole. The suspension is pref. introduced at pressure high enough for partial penetration in rock clefts and fissures. It pref. comprises concentrated magnesium solution and powdered magnesium oxide, enriched with rock dust and drilled material. This permits successful use of standard drilling assemblies in terrain sensitive to water, or loose, or conducting gas.