No Comments

Hammermill

A milling machine that utilizes a series of revolving hammers to pulverize falling rock led through a chute

No Comments

Hammer drill

A rock drill powered by compressed air with a clutch that allows it to not only spin the drill bit, but also a percussive hammering action

No Comments

Halide

A group of minerals whose chemical compound consists of a halogen with a more electropositive element or group

No Comments

Half-life

Term used to describe a radioisotopes decay to 50% of its current energy

No Comments

Hackly

Said of rocks with a jagged or fractured surface

No Comments

Habit

A general term used to describe a rock by its surficial appearance including crystal form

No Comments

Headwall

A retaining wall at one or both ends of a culvert structure

No Comments

Headframe

The steel, concrete or timber frame at the top of a shaft usually rigged to support hoist cables

No Comments

Hard-rock mining

Mining solid ore by drilling, blasting, milling and eventually refinement of minerals generally not emplaced by any glacial activity or erosion