Chat. XIII.
1IORING, ETC.
1063
All the varieties of chisels that have been employed cannot be enumerated; those whichhave been found most useful have been selected ; they are of different dimensions, madeto suit the operations they are intended for: the chisels 2^ inches diameter are cleared outby a gouge inches diameter, and when withdrawn, the hole is widened by another of3 or 4 inches in diameter, and so on : where rocks or hard bodies are to be pierced, drillsof a conical form are used, and to bring up loose stones screw chisels; for clay, scoops orgouges.
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BORING INSTRUMENTS.
The tools employed by the miners consist of a pick, one side of which is used as ahammer, and called a poll, the gad which has a steel wedge, and the shovel, which usuallyhas a pointed form, for the purpose of penetrating hard and coarse rubbish. The boreris an iron bar tipped with steel, formed like a chisel, and is used by one man holding itstraight in the hole made to receive it, and giving it a constant rotation on its axis, whilstanother strikes the head with an iron mallet. This hole is kept constantly cleared outby a scraper, which is a flat iron rod turned up at one end. The wheelbarrow forunder ground work differs from that here represented by not having any legs; when earthis to be removed at the top, they are made generally of this form : scoops and shovels varyin their form according to their application.
In sinking the Shaft of a Mine, it frequently occurs that water is met with in suchquantities, that cast-iron caissoons become necessary : in some of the deepest at Newcastlethey are sunk 180 fathoms. The operation of sinking a shaft is extremely simple:two or more workmen are employed digging, whilst others at the top, by means of awindlass, hoist the soil; as the depth increases, so does the labour, and either a steam-
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Fig. If 30.
Fig. 1529.
miners’ tools.
BARROWS.
engine or horse-mill is applied, called a whim or whimsey, for that purpose. The sidesof the shaft are walled up or steined as it is sunk, and great care taken to prevent the
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