Mining Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

L

Lamp-House - A room or building at the surface of a mine, provided for charging, servicing, and issuing all cap, hand, and flame safety lamps held at the mine.

Layout - The design or pattern of the main roadway and workings.

Leaching - Extracting a soluble metallic compound from an ore by dissolving it in a solvent, such as water, sulfuric acid, etc. and then recovering the metal by precipitation.

Lignite - A brownish-black coal in which the alteration of vegetal material has proceeded further than in peat but not so far as subbituminous coal.

Liquid Oxygen Explosive (LOX) - Sawdust or other suitable material, formed into cartridges and dipped into liquid oxygen before use in blasting.

Loader - A mechanical shovel or other machine for loading coal, ore, mineral, or rock.

Loading Machine - A machine for loading materials such as coal, ore, or rock into cars or other means of conveyance for transportation to the surface of the mine.

Loading Ramp - A surface structure, often incorporating storage bins, used for gravity loading bulk material into transport vehicles.

Locomotive - An electric engine, either operating from current supplied from trolley and track or from storage batteries carried on the locomotive.

Longwall - The coal seam is removed in one operation by means of a long working face or wall, thus the name. The workings advance (or retreat) in a continuous line which may be several hundreds of yards in length. The space from which the coal has been removed (the gob, goaf, or waste) is either allowed to collapse (caving) or is completely or partially filled or stowed with stone and debris. The stowing material is obtained from any dirt in the seam and from the ripping operations on the roadways to gain height. Stowing material is sometimes brought down from the surface and packed by hand or by mechanical means.

Low Coal - Coal occurring in a thin seam or bed.

Lump Coal - Bituminous coal in the large lumps remaining after a single screening that is often designated by the size of the mesh over which it passes and by which the minimum size lump is determined. Also, the largest marketable size.