The continual poverty which hindered the successful prosecution of the war against the Hussites, and which at times placer Sigismund in the undignified position of having to force himsel, as an unwelcome guest upon princes and cities, had, however, one good result.
The term 1 is not limited to underground operations, but includes also surface excavations, as in placer mining and open-air workings of coal and ore deposits by methods similar to quarrying, and boring operations for oil, natural gas or brine.
For the special methods by which placer deposits are mined see Gold.
In early days the placer gold mines of the Columbia, Fraser and Caribou attracted miners from everywhere, but these have declined, and lode mines supply most of the gold as well as the other metals.
In the placer or alluvial deposits, the precious metal is found usually in a water-worn condition imbedded in earthy matter, and the method of working all such deposits is based on the disintegration of the earthy matter by the action of a stream of water, which washes away the lighter portions and leaves the denser gold.
The first permanent settlements in Matto Grosso seem to have been made in 1718 and 1719, in the first year at Forquilha and in the second at or near the site of Cuyaba, where rich placer mines had been found.