Prior to the 1870s or 1880s, nearly all of the significant mineral deposits in Canada were discovered accidentally by individuals who were not actively searching for deposits. The discovery of placer gold in the Cariboo district in 1859 resulted in gold and basemetal prospecting in the mountainous regions of British Columbia and also in gold prospecting in the Yukon Territory. Similarly, the discovery of lode-gold deposits in Nova Scotia resulted in widespread prospecting activity there. Prospecting activity slowly spread to other parts of Canada. In 1909, prospectors found high-grade gold quartz veins in the Porcupine District of Ontario (now the City of Timmins). More than 2200 t of gold have been produced from this district and production continues from mines there, both old and new. In 1911, prospectors discovered another major gold deposit, which became known as the “Golden Mile,” at what is now the town of Kirkland Lake, Ontario. Some 800 t of gold have been recovered from the six or more mines on this single gold deposit. Production had continued there until 1999 from the one remaining mine, the Macassa mine, which is currently closed awaiting higher gold prices. In the province of Quebec, immediately to the east of Ontario, many important gold deposits, the large Noranda copper-gold deposit, and other basemetal deposits were discovered, beginning in the 1920s, by prospectors working along what became known as the Rouyn–Val-d’Or gold belt. Additional discoveries are still being made along this belt. Prospectors spread through northern Quebec, Ontario, Manitoba and Saskatchewan, making discoveries and arriving at the Yellowknife gold district in the Northwest Territories in the mid-1930s. Many new orebodies were discovered in these previously unknown gold-bearing areas.

In these early days of the industry, many prospectors were “grubstaked” (that is, their prospecting expenses were financed by local business people, in some cases by individual business people and sometimes by “syndicates” of several people in return for an interest in any discoveries made by the prospectors). Small companies, known as “junior companies,” were formed to explore for discoveries and hopefully to develop mines on deposits found. They obtained the needed funding by selling company shares to the public.

Until float-equipped aircraft became generally used for transportation into remote areas of Canada, prospectors searching for mineral showings in the Canadian Shield normally traveled by canoe and lived in tents. In the 1920s and 1930s, many mining companies formed their own exploration departments, employing their own geologists and prospectors. Except for gold and silver, metal prices were low during the Great Depression of the 1930s, and, as a result, exploration for non- precious metals was severely reduced. In 1934, the United States increased the gold price from US$20.67 to US$35.00 per troy ounce (31.103 grams), leading to a major increase in gold exploration, gold mine development and gold production in Canada. In 1939, war soon brought exploration to a halt, except exploration for strategic minerals not normally available from sources in North America, such as chromite, manganese, tin and tungsten. At most mines, work to replace the ore mined by new reserves either ceased or was cut to an absolute minimum. When the war with Germany began, the United States was a neutral nation and Canada had to pay for needed war material imports with U.S. dollars or with gold. As a result, the manpower, equipment and supplies needed for gold mining in Canada received Canadian government priority. In 1941, a lend-lease agreement was worked out so that war materials could be obtained from the United States on credit. Gold mining lost its priority and it became impossible for many gold mines to obtain the people and supplies that were needed to continue to produce. The result was rapid closure of many of the gold mines in Canada, and employment and production were cut back at those gold mines that did continue to produce. When the war ended, gold exploration resumed in Canada in 1945 and 1946, but inflation and a fixed gold price soon made it unattractive to explore for gold. New exploration opportunities soon appeared. There were urgent military requirements for uranium. Exploration for that metal was greatly assisted during the 1940s by use in Canada and elsewhere of the Geiger counter, invented in Germany in the 1920s and adapted in Canada in the early 1940s as a field instrument for uranium 6 A History of Mining and Mineral Exploration in Canada exploration. Subsequently, the Canadian invention of the much more sensitive scintillometer as a mineral exploration instrument in the early 1950s provided a sensitive radiation detector that could detect uranium from much greater distances than had been possible with the Geiger counter. The subsequent invention of the gamma ray spectrometer made it possible to distinguish radiation from specific radioactive elements, making it possible to determine whether the radiation came from uranium, thorium or other elements – something that the Geiger counter and scintillometer had been unable to do.

The Canadian mineral industry was essentially immature before the early 1950s. The availability of new geophysical methods, requiring sophisticated equipment, transformed the nature of exploration, while generally attractive metal prices and the substantial number of world-class base-metal and uranium orebody discoveries being made in various parts of Canada soon resulted in a rapid rise in exploration expenditures in Canada during the first half of the 1950s. Since 1946, more than 2000 metal deposits, for which sufficient exploration work has been done to measure tonnage and grade, have been discovered in Canada, an average of about 40 deposits annually. Only some of these deposits constitute orebodies.

Source: http://www.nrcan.gc.ca/ms/pdf/hist-e.pdf