Having sunk to the “wash,” or “drift,” the digger, by means of one or more of the appliances mentioned above, proceeds to separate the gold from the clay and gravel in which it is found.  Of course in large alluvial claims, where capital is employed, such appliances are superseded by steam puddles, buddles, and other machinery, and sometimes mercury is used to amalgamate the gold when very fine.  Hydraulicing is the cheapest form of alluvial mining, but can only be profitably carried out where extensive drifts, which can be worked as quarry faces, and unlimited water exist in the same neighbourhood.  When such conditions obtain a few grains of gold to the yard or ton will pay handsomely.

Lode or reef mining, is a more expensive and complicated process, requiring much skill and capital.  First, let me explain what a lode really is.  The American term is “ledge,” and it is not inappropriate or inexpressive.  Imagine then a ledge, or kerbstone, continuing to unknown depths in the earth at any angle varying from perpendicular to nearly horizontal.  This kerbstone is totally distinct from the rocks which enclose it; those on one side may be slate, on the other, sandstone; but the lode, separated usually by a small band of soft material known to miners as “casing,” or “fluccan,” preserves always an independent existence, and in many instances is practically bottomless so far as human exploration is concerned.

There are, however, reefs or lodes which are not persistent in depth.  Sometimes the lode formation is found only in the upper and newer strata, and cuts out when, say, the basic rocks (such as granite, etc.) are reached.  Again, there is a form of lode known among miners as a “gash” vein.  It is sometimes met with in the older crystalline slates, particularly when the lode runs conformably with the cleavage of the rock.

Much ignorance is displayed on the subject of lode formation and the deposition of metals therein, even by mining men of long experience.  Many still insist that lodes, particularly those containing gold, are of igneous origin, and point to the black and brown ferro-manganic outcrops in confirmation.  It must be admitted that often the upper portions of a lode present a strong appearance of fire agency, but exactly the same appearance can be caused by oxidation of iron and manganese in water.

It may now be accepted as a proven fact that no true lode has been formed, or its metals deposited except by aqueous action.  That is to say, the bulk of the lode and all its metalliferous contents were once held in solution in subterranean waters, which were ejected by geysers or simply filtered into fissures formed either by the shrinkage of the earth’s crust in process of cooling or by volcanic force.