is a process of the cylindrical form mine
working — well
, hole (artificial cylindrical deepening
in solid medium (rock, concrete) with diameter of up to 75 mm and depth of up to
5 m. They are used for blast placing in case of blasting, for roof bolting,
water or cement injection into the circumfluent rock mass etc. In shot-hole or
shaft drilling jackhammers, electric drills and other light drilling machines
are used for rock failure at bottomhole.
Generally, drilling is done in
earth crust and occasionally it is done in manufactured materials (concrete,
asphalt and others). In some cases drilling involves lining with casing and
cement grouting in annular clearance between casing and hole walls (generally in
case of longhole drilling).