The next most famous lode is that of Leadville, Colorado, which from 1879 to 1889 yielded $147,834,186, chiefly in silver and lead.
About this lode grew up Virginia City.
The Broken Hill lode is the largest yet discovered.
In early days the placer gold mines of the Columbia, Fraser and Caribou attracted miners from everywhere, but these have declined, and lode mines supply most of the gold as well as the other metals.
This was a stock speculation based on the remarkable output ($ 3 00,000,000 in 20 years) of the silver " bonanzas " of the Comstock lode at Virginia City, Nevada, which were opened and financed by San Francisco capitalists.
In April 1872 came the revulsion; there was a shrinkage of $60,000,000 in ten days; then in 1873 a tremendous advance, and in 1875 a final and disastrous collapse; in ten years thereafter the stock of the Comstock lode shrank from $3,000,000 to $2,000,000.
The United States came into prominence in about 1860, and the discovery of the famous Comstock lode in Nevada led to an enormous increase in the production.
The production of this lode declined in 1876, but the total production of this country was increased by discoveries in Colorado (Leadville) and Nevada (Eureka); and in more recent years silver-producing areas in other states (Montana, Utah, Idaho) have been exploited.
The mines there occur in gneiss and schists, which are probably of Archean age; the lode has in places been worked for a width of over 200 ft.
The most powerful impulse to mining operations, and the immediate cause of a somewhat lengthy period of wild excitement and speculation, was the discovery and successful opening of the Comstock lode in 1859, in the western part of what is now Nevada, but was then part of Utah.
In New South Wales lode tin occurs principally in the granite and stream tin under the basaltic country in the extreme north of the state, at Tenterfield, Emmaville, Tingha, and in other districts of New England.
In 1859 the discovery of the famous Comstock Lode in Western Nevada led to the building of Virginia City, a prosperous community on the side of a mountain where human beings under ordinary conditions would not have lived, and eventually brought a new state into existence.
Striking the shafts of the Comstock Lode, securing ventilation and cool air for the miners, draining the mines above its level, and obviating much pumping and hoisting.'
Shinn, The Story of the Mine as Illustrated by the Great Comstock Lode of Nevada, in The Story of the West " series (New York, 1896) The Silver Mines of Nevada (New York, 1864); M.
I and 2 illustrate the development of a metal-vein by two adits, two inclined shafts in the lode, and by a deep vertical shaft connected with the lode by horizontal cross cuts.
This was especially the case on the " Mother Lode,".where highly promising results were obtained.
From 1859 to 1902 the total yield of this lode was $204,653,040 in silver and $148,145,385 in gold; the average annual yield from 1862 to 1868 was above eleven millions; the maximum yield $36,301,537 in 1877; and the total product to July 1880 was variously estimated at from $304,752,171.54 to $30618125125.
The lode was an ore channel of great dimensions included within volcanic rocks of Tertiary age, themselves broken through pre-existing strata of Triassic age, and exhibited some of the features of a fissure vein, combined in part with those of a contact deposit and in part with those of a segregated vein.
The Broken Hill silver lode is the largest as yet discovered; it varies in width from 10 ft.
In mineral veins and lodes crystallized quartz is usually the most abundant gangue mineral; the crystals are often arranged perpendicular to the walls of the lode, giving rise to a "comby" structure.
Mackay and his partners, Flood, Fair and O'Brien) in the Comstock Lode of the Great Bonanza mine, the average annual yield was over $26,000,000.
Lode tin, as tinstone derived from primary deposits is often termed, is mined in the ordinary method, the very hard gangue in which it occurs necessitating a liberal use of explosives.
At many of the mines at Kalgoorlie, Western Australia, large quantities of ores of telluride of gold have been found in the lode formations.
Either in the shaft furnace or the reverberatory; the former is the better suited to stream tin, the latter to lode tin, but either ore can be smelted in either way, although reverberatory practice yields a purer metal.
The metalliferous portion of the lode was similarly distributed in great masses, known as bonanzas.