A glossary of mining and metallurgical terms
A glossary of mining and metallurgical terms
A glossary of mining and metallurgical terms
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A GLOSSARY OP MINIXG AND MKTA LLURGICAI. TERMS. 55<br />
Lon(/-iral/. A method <strong>of</strong> coal minini^ by wliieli the whole seam is<br />
taken out as the working faces progress, ami the ro<strong>of</strong> is allowed to<br />
fall behind the workers, except where passages must be kept open,<br />
or where the gob being packed in the space formerly occupied by the<br />
coal, prevents caving. According as the work <strong>of</strong> extraction begins<br />
at the boundary <strong>of</strong> the ivinnliig, <strong>and</strong> converges back to the shaft, or<br />
begins with the coal nearest the shaft <strong>and</strong> proceeds outward to the<br />
boundaries, it is called long-wall retreating or long-wall advancing.<br />
Loob or loobs, Corn. The clayey or slimy portion washed out <strong>of</strong><br />
tin-ore in dressing.<br />
Loop. See Loup.<br />
Loop-drag. An eye at the end <strong>of</strong> a rod through which tow is<br />
passed for cleaning bore-holes.<br />
Loose-end. A gang\my in long-wall working, driven so that one<br />
side is solid ground while the other opens upon old workings. See<br />
Fast-end.<br />
Lorry. A h<strong>and</strong>-car used on mine tramways.<br />
Lost level, Cony.. " Level " is " lost " when a gallery has been<br />
driven with an unnecessarily great departure from the horizontal.<br />
Loup. The pasty mass <strong>of</strong> iron produced in a bloomary or pud-<br />
dling furnace. See Puddle-ball.<br />
Lowe, Newc. a light. A " piece <strong>of</strong> lovve " is part <strong>of</strong> a c<strong>and</strong>le.<br />
Luckhart furnace. A continuously working shaft-furnace for roast-<br />
ing quicksilver ores, having the fireplace in the shaft at the bottom,<br />
protected by a cast-iron ro<strong>of</strong>. The fuel is wood.<br />
Lum. A chimney over an upcast pit.<br />
Lump-coal, Penn. See Coal.<br />
Lurmann front. An ari-angeraent <strong>of</strong> water-cooled castings through<br />
which iron <strong>and</strong> cinder are tapped from the blast furnace, thus avoid-<br />
ing the use <strong>of</strong> a forehearth. See Closed front.<br />
Lying-wall. See Foot-ioall.<br />
Machine-whha. A rotary steam-engine for winding.<br />
Magistral, Sp. A powder <strong>of</strong> roasted copper pyrites, used in the<br />
amalgamation <strong>of</strong> silver ores.<br />
Main-rod, CoRN. See Pump-rod.<br />
Mainway. A gangway or principal passage.<br />
Makings, Newc. The small coals hewn out in kii-ving.<br />
Malleable castings. Small iron castings made malleable by "an-<br />
nealing" oi- decarburizing by cementation in powdered hematite<br />
or other oxide <strong>of</strong> iron.
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