A small hole drilled into a rock or boulder into which an anchor bolt or a small charge or explosive may be placed; used in quarries for breaking large blocks of stone or boulders.



Related Terms

MUDCAP

A quantity of wet mud, wet earth, or sand used to cover a charge of dynamite or other high explosive fired in contact with the surface of a rock in mud blasting.

INDENTED BOLT

A type of anchor bolt that has indentations to hold better in cemented grout.

HAWSEPIPE

The shaft or hole in the side of a vessel's bow through which the anchor chain passes.

EYELET

  1. A bolt with a loop at one side 2. A small ring or barrel-shaped piece of metal inserted into a hole for reinforcement.

PLASTER SHOOTING

A surface blasting method used when no rock drill is necessary or one is not available; consists of placing a charge of gelignite, primed with safety fuse and detonator, in close contact with the rock or boulder and covering it completely with stiff damp clay.

BLASTHOLE

  1. A hole that takes a heavy charge of explosive. 2. The hole through which water enters in the bottom of a pump stock.

HEAVY LIFT CHARGE

A charge typically imposed when special lifting gear is required to handle a given piece of cargo, which may be of either heavy weight or of large dimensions (often referred to as 'out of gauge' when dealing with container vessels).

PERCUSSION BIT

A rock-drilling tool with chisellike cutting edges, which when driven by impacts against a rock surface drills a hole by a chipping action.

PLASMA TORCH

A torch in which temperatures as high as 50,000 C are achieved by injecting a plasma gas tangentially into an electric arc formed between electrodes in a chamber; the resulting vortex of hot gases emerges at very high speed through a hole in the negative electrode, to form a jet for welding, spraying of molten metal, and cutting of hard rock or hard metals.

CORE DRILL

A mechanism designed to rotate and to cause an annular-shaped rockcutting bit to penetrate rock formations, produce cylindrical cores of the formations penetrated, and lift such cores to the surface, where they may be collected and examined.

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