OF CENTRAL CANADA PART III. 197 



between each pair of galleries or "levels" as these are commonly called, 

 is extracted by a' system of step-like excavations, technically known as 

 " stoping." When a vein is nearly vertical in its position, a shaft 

 may of course be carried down to a great depth upon the substance 

 of the vein itself, and the material thus taken out of the shaft will 

 often pay for the sinking of the latter. Shafts are usually rectangu- 

 lar in form, and are not only strongly framed at the sides, at least 

 for a certain depth, but are commonly sub-divided vertically into two 

 or more compartments by brattice-work or planking ; one of these 

 compartments being reserved for the pump rods and also for the 

 buckets or kibbles used for sending up the ore, or bringing it, in 

 technical phraseology, to grass ; and another being fitted with ladders 

 or with a special lifting apparatus for the miners. An adit is a hori- 

 zontal or nearly horizontal gallery driven from the side of sloping or 

 escarped ground, so as to strike the vein at a certain depth from the 

 surface outcrop of the latter. It serves in many cases, especially 

 where it opens out on a river bank, or on ground suitable for a tram- 

 way, &c., as a convenient roadway for bringing out the ore ; and if 

 at a sufficiently low level it may greatly facilitate the drainage of 

 the mine, and assist in the ventilation of the works. Where two 

 shafts are sunk upon the vein, they should be located, if possible, on 

 high and low ground, respectively, in order to promote ventilation. 

 The ore, when brought to the surface, is usually " cobbed " or hand- 

 dressed by children, and the assorted portions, thus broken up by 

 hammers, are brought into the state of powder by subjection to 

 stamps or crushers. Tha powder is then agitated with water in Jong 

 narrow troughs or flat circular tubs called " buddies," the latter kind 

 being furnished with revolving arms or sweeps to which brushes are 

 attached ; or it is shaken up with water in "jiggers " or tubs pro- 

 vided with movable sieves, until the metallic particles by reason of 

 their greater weight collect together, and so become separated, more 

 or less thoroughly, from the lighter earthy particles or refuse, com- 

 monly known as waste slimes or tailings. The dressed or concen- 

 trated ore is then ready for the furnace or reducing works. 



