Farrow's military encyclopedia : a dictionary of military knowledge . certain preliminaryoperations of a mechanical kind which metallic oresundergo, such as crushing, jigging, washing, etc.,which we shall describe here, as they are essentiallythe same for the ores of lead, copper, tin, zini. andindeed most of the metals. Ores are first broken upwith hammers, into piices of a convenient size forcrushing or stamping. Waste material, such as piecesof rock, spar, etc., which always accompany ore,are as far as possilile picked out by hand, and theore itself is arranged in sorts according to its jiu
Farrow's military encyclopedia : a dictionary of military knowledge . certain preliminaryoperations of a mechanical kind which metallic oresundergo, such as crushing, jigging, washing, etc.,which we shall describe here, as they are essentiallythe same for the ores of lead, copper, tin, zini. andindeed most of the metals. Ores are first broken upwith hammers, into piices of a convenient size forcrushing or stamping. Waste material, such as piecesof rock, spar, etc., which always accompany ore,are as far as possilile picked out by hand, and theore itself is arranged in sorts according to its kinds of apparatus, such as riddles, sieves,etc., are then used for separating it into (iifferentsizes, in order to secure a uniform strain on thecrushing machinery. In one of the most a]ii)rovedforms of crushing-mills the ore is raised by means ofsmall wagons to a i)latfiirm, where it is ready to bosup[)lied to the crushing-rollers through an rollers are mounted in a strong iron frame,held together by ?\\Tought-irou bars, and bolted to. strong beams- Their distance apart is regulated bymeans of a lever to which a weight is attached. Thebearings of the rollers slide in grooves, so that whenany extra pressure is put upon them by a large orhard piece of ore, the lever rises, and allows thespace between the rollers to widen. The crushedore falls upon a series of sieves, which are made tovibrate. These have meshes increasing in finenessas they descend; and the upper two are so wide thatpieces of ore too large to pass through them areconducted into the lower part of the Ijucket-wheeland raised again to the platform to be lower four sieves separate the remaining portionof the crushed ore into different degrees of fineness,which is collected in pits. A sectional view of the Blake Ore Crusher, stand-ard in the United States and abroad, is shown in A three-sided framework of cast-iron, with broadflanged base, holding the movable jaw. J, in
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Keywords: ., bookcentury1800, bookdecade188, booksubjectmilitaryartandscience
