Next page Previous page

combustible gases layer

A sheetlike accumulation of combustible gases under the roof of a mine
roadway where the ventilation is too sluggish to dilute and remove the
gas. Although the term is new, the hazard existed since the earliest days
of coal mining. A combustible gases layer may be specified as one in which
the gas is 5% or over and of a length greater than the width of the road
in which it occurs. See:pocket of gas
See also:stratification of methane

combustible shale

See:tasmanite

combustion

The action or operation of burning; the continuous combination of a
substance with certain elements, such as oxygen or chlorine; e.g.,
accompanied by the generation of light and heat.
See also:ignition temperature

combustion arch

A flat or curved refractory roof over a furnace to promote combustion by
reflection of heat. AISI

combustion engineer

An engineer with practical training and knowledge of all kinds of fuels
and their combustion characteristics. In general, the engineer lacks the
technical qualifications of the fuel technologist. Nelson

combustion method

A method for the quantitative determination of certain elements (such as
carbon, hydrogen, and nitrogen) in organic compounds by combustion.
Webster 3rd

comedown

Softish stone occurring in the roof of a coal seam; it easily falls when
coal is removed. Syn:comb dung

comendite

A sodic rhyolite containing alkalic amphibole and/or pyroxene.

come out

To withdraw or hoist the drill string or tools from a borehole.
Long

come water

The constant or regular flow of water in a mine proceeding from old
workings or from water-bearing rocks.

comfort air conditioning

Air conditioning that controls the atmosphere that human beings breathe.
Hartman, 2

coming up to grass

Eng. Common terms used by miners for the word basset, or outcrop. Also
coming up today.

Comleyan

Lower Cambrian. AGI

commercial deposit

A deposit of oil, gas, or other minerals in sufficient quantity for
production in paying quantities. Williams

commercial explosives

Explosives designed, produced, and used for commercial or industrial
applications rather than for military purposes. Meyer

commercial granite

A general term for a decorative building stone that is hard and
crystalline. It may be a granite, gneiss, syenite, monzonite,
granodiorite, anorthosite, or larvikite. See also:black granite
AGI

commercially disposable coal

A statistical term referring to saleable coal, less colliery consumption
and coal supplied to employees. BS, 4

commercial marble

A crystalline rock composed predominantly of one or more of the following
minerals: calcite, dolomite, or serpentine, and capable of being polished.

commercial mine

A mine operated to supply purchasers in general as contrasted with a
captive mine. Zern

commercial ore

Can. Mineralized material currently profitable at prevailing prices.
Hoffman

commercial quantity

A quantity of oil, gas, or other minerals sufficient for production in
paying quantities. Williams