Question

long hole drilling method​

Answer 1

In Top Hammer long hole drilling, namely production drilling, the hole length is typically between 10 m up to 40 m and the hole size vary from 51 mm up to 127 mm. The long holes are drilled with extension rods. ... Long hole drilling is used in various mining methods like sublevel open stoping and VCR stoping.

Answer 2

Long hole ledging is the method whereby blind holes are drilled parallel to the advancing face from a centre gully. Typically, the ledging blind long holes are shorter than the in-stope through holes (i.e.: 8 m compared to 15 to 20 m).