Apparatus for water jet and impact drilling and mining

摘要

The invention is a novel method and apparatus for subterranean drilling and mining, particularly suited to alluvial deposits. The method uses water jets from the lower end of the apparatus to loosen and remove soil. Part of the water is bled off to raise a piston and associated weight, the water being evacuated from the cylinder in which the piston operates from time to time to give periodic impulses to the outer casing. Air may be admitted to the system during the mining mode to increase its efficiency.