ribs or narrow pillars are worked away, commencing in the middle at e and working both ways.

LONG-SHIFT (S.). From say 6 A.M. on Sunday till 6 A.M. on Monday, the time during which the furnaceman and horse-tender has to be underground under certain circumstances.

LONG-TON. A weight of more than 20 cwt. In canal trade sometimes 25 or more cwt. of coals are allowed to the ton.

LONGUES TAILLES (F.). See Long-wall.

LONG-WALL. A system of working coal and ironstone in which the whole of the seam is gotten or worked away, and no pillars left in excepting the shaft pillars, and sometimes main road pillars, the goaves being more or less filled up to prevent large accumulations of firedamp. There are two modes of working under the long

wall plan. No. 1, to work outwards, commencing near the shafts and taking out all the coal, carrying the roads in the goaf by pack walls; or, secondly (No. 2),

by driving out the main roads to the boundary and then bringing back the faces and leaving all the goaf behind.* See plan, Fig. 91.

* In the Long-wall system the weight assists greatly in extracting the coal, an advantage lost by other systems of working. See Fig. 92,

showing how the subsidence of the roof helps to break down the coal

at the face.

M

LONG-WEIGHT. See Long-ton.

LONG-WORK. 1. (Y.) A system of working coal somewhat in the manner shown in Fig. 17.

2. (Lei.) Ancient plan of working the Main coal of Moira. Each stall or long-work was about 150 yards in length (usually two in a pit), and was worked by about twenty butties, the coal being got on the gob-road system.

LOOKING (N. S.). Examining the unwalled sides of a sinking pit.

LOOPS. See D links.

LOOSE! or LOOSE ALL! (N.) See Kenner.

LOOSE END. The limit of a stall next to the goaf, or where the adjoining stall is in advance.

LOOSE NEEDLE. See Dialling.

LOOSING (S. S.).

Lowering a cage, &c., into or down

a shaft or pit.

LORDSHIP (S.).
LORRY (Y.).

Royalty or acreage rent.

A running bridge over a sinking pit top upon which the bowk is placed after it is brought up for emptying.

LOSE. 1. To work a seam of coal, &c., up to where it dies out or is faulted out of sight. This is called losing the coal.

2. To be unable to work out a pillar on account of thrust, creep, gob-fire, &c.

3. A pit-shaft is said to be lost when it has run in or collapsed beyond recovery.

LOUGHS (L.). Irregular cavities in iron mines. Low. 1. (N.) A candle or other naked light carried by a miner.

2. (F. D.) Minor channels communicating with horses, are termed lows.

Low ROPE (N.). A piece of rope used as a torch.

LUM. 1. (N.). A chimney placed on the top of an upcast shaft to carry off the smoke, &c., and to increase the ventilating current.

2. (D.) A basin or natural swamp in a coal seam, often running several hundred yards in length.

LUMBERINGS (D.). Bumps over old workings.
LUMPS (S. S.). Coal of largest size by one.

is

LURRY. 1. (Y.) A tram to which an endless rope attached, fixed at the inbye end of the plane, forming part of an appliance for taking up the slack rope. See Fig. 93.

2. A movable platform on wheels, the top of which is made on a level with the bank (1) or surface. It is run over the mouth of a pit-shaft for a bowk to be lowered down upon when reaching the pit top.

LYE (S.). A siding for tubs in a mine.

LYPES (S.). Irregularities in the roof indicating danger from falls.

M.

MACHINE. A weighbridge or weighing machine upon which wagons, trams, carts, &c., are weighed, either with or without their loads of coals, &c.

MACHINE-MAN. One who weighs coals, &c., and keeps an account of the number of tubs sent to bank (1). MACHINE WALL. The face at which a coal-cutting machine works.

MAIDEN FIELD or GROUND. A coalfield, &c., which has not been tapped.

MAIN DOOR. See Bearing Door.

MAIN BOARD-GATE (Y.). The heading which is driven to the rise of the shaft. It is usual to make it larger in sectional area than an ordinary board-gate. See a, Fig. 9 [Bank-work].

MAIN ENGINE (N.). The surface pumping engine, usually of the Cornish type.

MAIN ROAD. The principal underground way in a district along which the produce of the mine is conveyed to the shafts, generally forming the main intake air course of each district.

MAIN ROPE. A system of underground haulage in which the weight of the empty tubs is sufficient to draw the rope inbye.

MAIN SUIT (B.). A heavy spring or feeder of water. MAINTENAGE (F.). The face of workings in rearing or vertical seams, consisting of a series of little steps