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it is now tolerably well ascertained that many of the metallic veins have resulted from electro-chemical action.
Metallic veins, or fissures, generally run for a very considerable extent in a horizontal direction, and their direction below the surface is generally more or less inclined from the perpendicular, and very commonly forms an angle of from seventy to eighty degrees with the horizon. They extend downwards to an unknown depth, and their width varies from inches to feet. Their course is generally from east to west. They seldom consist of metal in a pure and malleable state, but in a chemical combination with another substance; in this state it is called an ore, and the metal is separated from it by the process of smelting, which will hereafter be described.
There are some technical expressions regarding the situation and direction of metallic veins which it would be well to remember. The thickness, extent, and direction of a vein of metal depends upon many circumstances. If it continues in a straight line, and of uniform thickness, it is called a rape ; if it occasionally swells out in places, and again contracts, it is called a pipe vein, and the wider parts of the vein are called floors. Sometimes the vein divides itself into two branches, and is then said to take horse ; at other times a cross vein will interfere with it, and heave, or lift it, as it were, 10 or even 20 feet out of its course.
Workings within a Miur.
We have already described the manner in which the metallic veins lie in the crust of the earth. The substance is generally called the vein stone, and, of course, it is the object of the miner to extraet it, for the possession of the ore which it contains. Should the vein be visible on the surface, which is not often the case, the miner's first operation is to drive a horizontal passage, called an adit, upon the vein, following all its windings and irregularities; and excavations being made above and below, the ore is readily obtained. Should want of air render it desirable, as the vein descends in the earth, à second outlet is made from the surface communicating with the vein by sinking a pit or shaft; and it often happens that shafts are suink at various distances along the adit of a vein for a considerable length.
But when the vein is not visible at the surface of the earth, and the metallic treasure is supposed to be underneath, from various indications known to the miner, a mine is opened by sinking a shaft from the top, which commences much in the manner of digging a common well. At the depth of 10 or 12 feet, the vegetable mould and loam being passed, the workmen come to the hard rock, and then the work becomes slower and more difficult, and the pick, and gad, and borer, and mallet are put in requisition, and the aid of the mighty agent, gunpowder, is called in to blast the rock from time to time. To get rid of the matter broken up in the shaft,
a windlass is erected over the top of it, and the rubbish is drawn up in baskets called kibbles. The sides of the shaft are supported by a frame-work of timber, to prevent them from falling in upon
the workmen, and so the process continues till the vein of ore is reacheda
Trials are now made upon the vein, by cutting small horizontal passages in it called levels, and while this operation is going on the shaft is gradually sunk deeper, and when it arrives at a certain depth below the first level, generally about 10 or 12 fathoms, a short passage or cross-cut is driven into the vein, and a second level commenced in the same manner. In this way the shaft continues to be sunk deeper, and new cross-cuts and levels to be driven, one below the other, at stated intervals, each level, of course, laying open and exploring the portion of the vein through which it passes.
When the ventilation becomes imperfect, owing to there being but one communication with the external air, a small pit called a winze is sunk from the upper level to the end of the one below, and this communication having been made, a free current of air is at once established. Sometimes, after cutting a vein shafts are sunk upon it in an inclined position, so as to avoid the necessity of cross-cuts.
The operation just described constitute what is called tut-work, and is paid for at so much per fathom, forming one of the heaviest expenses of a mine; but when the vein has been thus laid open,
the reward of the miner begins. The workmen called tributers generally begin working at the bottom of the mass, attacking the vein on the richest points only; by working from beneath, the ore, when detached from the vein, falls down at once on the level below, and is easily removed. The tools used in the working are generally the pick and bar, but recourse is frequently had to blasting, when great masses of the vein fall down at once upon the level, from which it is removed by handbarrows, and raised to the top by the whim.
The supports of a mine, when the ore has been excavated, are sometimes pillars left of the solid rock or vein, or at others, strong pieces of timber, which prevent the subjacent rock from falling upon the heads of the miners.
Something about the Month of Octaber.
HE orchards now are ripe and red, and golden runnets shine,
And grapes hang luxuriously upon the crimson-tinted vine ;
The woods their thousand gorgeous tints of fading beauty show,