Describes use of rotary drills to sink shafts at Arkansas bauxite mines. Standard oil-well rotary equipment is used, and the derricks are adapted from a type common in oil fields. It has been found that shafts in circular cross section, lined with streel casing surrounded by a cement sea, have structural advantages superior to those of shafts supported by timber and sheeting. Where formations are loose and water-filled, shaft sinking with a rotary drill is exceptionally practical, economical, and safe.

Shaft sinking for underground transportation purposes is a very complex technological process in mining and geotechnology which requires specific and specially designed technological equipment. This technological process is dealt with for a long time, since mining is one of the oldest industries in the world.This book presents the te