Gold Mining in British Columbia
The history of gold mining activity in British Columbia, Canada, started in 1858, when gold deposits were discovered and led to a great influx of miners the next year. The gold yielded was irregular due to the uncertainty of gold deposits worked and the climatic conditions in the zone. The unfavorable spring prevented the miners from reaching their claims till late, and heavy floods impeded their operations during the summer. The very general distribution of alluvial gold over the province indicated that different rock formations were source of gold in variables quantities. In this way, it was possible to determine the presence of coarse or heavy gold occurrence in veins located near the main deposit.
Gold miners indicated the presence of finer particles of gold that traveled far along the beds of the rapid rivers before they were reduced by attrition to invisible shreds, and some distribution systems helped to distribute the fine gold. The gold formation consisted of a series of talcose and chloritic, blackish, or green-grey slates or schists, which occasionally become micaceous, and showed evidence of greater metamorphism than the gold-bearing slates of California. Their geological horizon was considered a position intermediate between the more distinctive members of the Lower Cache Creek group of Selwyn and the base of the overlying Mesozoic rocks. Some geologists consider there are some equivalence to the auriferous rocks of California. By the denudation of the auriferous veins traversing these rocks, the gold was concentrated in Placers.
The greatest areas of these rocks appear in Connection with the disturbed region lying west of the Rocky Mountain Range, known in several parts of its lengths as the Purcell, Selkirk, Columbia, Cariboo and Omineca Ranges. Other considerable belts of auriferous rocks occurred beyond this region, as in the vicinity of Anderson River and Boston Bar, on the Fraser; at Leech River, and Vancouver Island. The Cariboo district, discovered in 1860 was the most permanent and productive zone and the presence of several streams, falling rapidly about their sources over rocky beds, descended into great V-shaped valleys, and in the lessening slope, the rock was canceled by gravel deposits that increased in thickness and extent until the valleys become U-shaped or flat bottomed, and little swampy glades were formed through which the stream flows tortuously and with gentle current. Williams’s and Lightning Creek yielded the greater part of gold in Cariboo. They were known from the first to be rich, but were especially suited for deep work, in having a hard deposit of boulder clay beneath the beds of the present water courses, which prevented the access of much of the superficial water to the workings. In regular mining operations, the rocky bottom of the valley was followed beneath 15 to 50 m of overlying clays and gravel, the course of the ancient stream was traceable by the polished rocks of its bed, and the course gravel and boulders which have filled its channel.
As an example of the methods employed and extent of mining operations required to reach the buried channels, the Van Winkle Mine on Lightning Creek is a good example. This claims covered about 700 m in length of the valley, the deepest part of the old channel of which was cleared out to a length of 500 to 550 m in October, 1876. The claim yielded the first dividend in December, 1873, having been expanded before gold was found in the channel. In reaching the buried channel a shaft was sunk at the lower or down-stream end of the claim, on the sloping side of the valley, where after having gone through a moderate depth of clay or gravel, the slaty rock of the district was reached. The shaft was continued through this until a depth supposed to be sufficient was attained. When a drift was started at right angles to the course of the valley, and if the right depth was chosen, either by rough estimation or calculation based on the required in other neighboring working, the old channel was struck, collecting in it from the whole upper part of the claim to be pumped to the surface by the shaft. In the Van Winkle mine the average depth of the workings was 23 m, the lowest shaft was placed 100 m from the creek on the opposite side of which the rock was seen to rise to the surface, forming steep cliffs.
The Cassiar mines were worked under enormous disadvantages, located in an almost Arctic climate where the soil was permanently frozen at a small depth below the surface on the shady slides of the valleys, with a short season, during which the water courses were liable to floods, disastrous to the mines, reached after a sea voyage from Victoria, by the River Stickeen. Gold in small quantities was found in several streams flowing into the Okanagan Valley, and Mission Valley was the most important.