After-damp-The mixture of gases remaining in a mine after an explosion of firedamp.

Air-The current of atmospheric air circulating through and ventilating the workings of a mine.

Air-shaft-A shaft used expressly for ventilation.

Air-stack--A ventilating chimney.

Air-way-Any passage in a mine through which air for ventilating purposes is passed.

Anemometer-An instrument used for measuring the volocity of a ventilating current.

Bearing in-Undermining.

Black damp-Carbonic acid gas CO2. It will not support combustion or life. Blower-A strong discharge of gas from a fissure.

Blown-out shot-A shot that has blown out the tamping without bringing down the coal.

Bonnet-A shield or covering over a cage to protect it and the miners from anything falling down the shaft. Bottom-The landing at the bottom of the shaft or slope; the floor, bottom rock or stratum underlying a coal seam. Brattice-A division or partition in a shaft, slope, heading, gangway or other underground working places for providing ventilation.

Brattice-cloth-A heavy cloth or canvas, often covered with water-proof material, used in the construction of doors and brattices instead of plank. Bridle-chains-Short chains by which the rope is attached to the cage, Buntons-Timbers placed horizontally across a shaft to carry the cage guides, also to strengthen the shaft timbers. Butty-A partner in a contract for driving or mining; comrade, crony. Cage-A platform on which the mine cars are raised and lowered in mine. Car-mine-car-Any car used for the conveyance of coal or mineral in a mine. Cap-A piece of plank used on the top of a prop.

Cartridge-Paper or water-proof cylindrical cases filled with gun-powder, forming the charge for blasting.

CH4-The chemical symbol for fire-damp. Charge-The amount of powder or other explosive used in one blast, or shot. Choke-damp-(See black damp). Chute (also spelled Shute)-Any passage through which the coal descends by gravity.

Clanney lamp-A safety-lamp invented by Dr. Clanney.

Clod-A layer of soft shale or slate, forming a very bad roof over a seam of coal. Coal measures-The carboniferous formation.

Colliery-The whole plant, including the mine and all adjuncts.

Column pipe-The pipe through which the water is conveyed from the mine pumps to the surface.

Creep, or squeeze-The gradual upheaval of the floor of a mine, due to the weight of the overlying strata.

Crib A structure composed of horizontal frames of timber laid upon one another, or a frame-work built like a log cabin. Cribbing-Timbering a shaft with cribwork, commonly extending from surface to the bottom.

Cropping out-Coming to the surface; outcropping.

Cross-cut-A small passage-way driven at right angles to the main heading or entry to connect it with a parallel (gangway or air-course.

Davy lamp-A safety-lamp invented by Sir Humphrey Davy.

Dead-work-Work which at the time it is done and of itself produces little or no profit.

Digging-Mining operations in coal or other

mines.

Dip-To slope downward from the surface; the inclination of a stratum of a coal seam. Ditch-The drainage gutter. Doors-Wooden doors fixed in underground roads to prevent the ventilating current from taking a short cut to the upcast airway.

driven into the seam from the surface. Drum-The revolving cylinder around which the winding rope is coiled.

Dump (1) A pile or heap of ore, coal, slate or rock. (2) The tipple by which the cars are dumped. (3) To unload a car by tipping it up.

Entry-Main hauling roads or gangways. Face, or working face-The place at which the coal is actually being worked away, either in a breast or heading.

Fall-(1) A mass of roof or side which has fallen in any part of a mine. (2) To blast or wedge down coal. Fan-Centrifugal mechanical ventilator, Fault-A fracture or disturbance of the stra

tum breaking the continuity of the seam. Fire-A word shouted by miners to warn one another when a shot is fired. Fire-boss-A man whose duty it is to examine the workings for accumulation of explosive gas, etc.

Fire-damp-The explosive gas of coal mines -light carburreted hydrogen; the chemical formula C H4.

Furnace-A large coal fire at or near the bottom of an upcast shaft, for producing a current of air for ventilating the mine. Gas-Fire-damp.

Goaf or gob-(1) A space from which the

coal has been worked away and the space more or less filled up. (2) The refuse or waste left in the mine. Gob-fire-Spontaneous combustion under

ground.

Guides-Vertical timbers fastened to the buntons to steady and guide the cage. Head gear-The pulley frame erected over a shaft.

Head-house-When head-frame is housed in, the structure is known by this name. Heading-A gangway or entry. Horseback- Natural channels cut or washed away by water, in a coal seam, and filled up with shale and sandstone. Sometimes a bank or ridge of foreign matter in a coal seam.

Incline-A slope, any inclined plane, whether above or below the surface. Indicator-Any instrument or device for indicating the position of the cage in the shaft.

In-take-The passage through which the fresh air is drawn or forced in a mine. Keeps-See Catches. Lagging-Small round timber, slabs or planks, driven in behind the legs and over the collar to prevent pieces of the roof from falling through

Landing-The top or bottom of a slope, shaft or inclined plane.

Latches-A synonymn of switch, applied to the split-rail and hinged switches. Long-wall-A system of working a seam of coal in which the whole of the seam is taken out, leaving no pillars, except sometimes a pillar to support the bottom of shaft.

Loader-One who fils the mine cars at the working place.

Manager-An official who has the daily control and supervision of a mine, both above and below ground.

Manway-A small passage used as a traveling way for the miner. Motive column-The length of column of air in the downcast shaft which would be equal in weight to the difference in weight of the air in downcast and upcast shaft. The power obtained by furnace ventilation is measured by the difference of the weight of the air in the two shafts. Mouth-The surface end of a shaft or drift. Narrow work-Headings, air-courses, gangways, entries, etc.

Natural ventilation-Ventilating a mine without furnace or other artificial means. Needle-A sharp-pointed metal rod, placed in a bore-hole during the tamping of the charge, to leave on its withdrawal an opening through which the charge can be fired. Nut coal-Coal that passes through an inch or an inch and one-half screen, and over a half-inch screen.

Out-crop-That portion of a vein, bed or any stratum appearing at the surface or occurring immediately beneath the soil. Output-The total product of a mine. Overcast - A passage through which the ventilating current is conveyed over an entry or air-course.

Parting-Any thin or inter-stratified bed of earthy material.

Pillar-A solid block of coal left to support the roof.

Pillar and room-A system of working coal by which solid blocks of coal are left on either side of rooms, entries, etc., to support the roof until the rooms are driven up, after which they are drawn out. Pitch-Dip or rise of a seam. Plan-The system on which mine is worked, as "long-wall," pillar and room," etc. Propping-The timbering of a mine, Prospecting-Examining a tract of country in search of minerals.

Pulley-The wheel over which a winding rope passes at the top of the head-gear. Regulator-A frame with a slide door to regulate the amount of air passing into any part of the workings.

Return air-Air that has passed through the workings.

Rib-The side of a pillar.

Roof-The rock lying above a coal bed or ore vein.