Y -L3-\ exist in concentrated form is rclativcly small, and of these places only four are kmowm to have the concentrated deposits in substantial amounts. The latter de- posits arc found in the Great Bear Lake region of northern Canada, the Belgian Congo, Colorado, and Joachinsthal in Czechoslovakia, Lesser but nevertheless fairly extensive deposits are knomm to exist also in Madagascar, India, and Russian Turkestan, while small occurrences are fairly well scattored over the globe.?* The pre-war market was doruinated by the Belgian in 1939 to share it in the ratio of 60 to ho,?33 @ proportion which presumably reflected what was then thought to be their respective reserves and productive capacity, However, it now appears likcly that the Canadian reserves are consid- erably greater than those of the Congo, In 192 the Gongo produced 1,021 tons of unusually rich ore containing 695.6 tons of U30g—or about 590 tons of uraniun netal 34 In general, however, the ores of Canada and the Congo are of a richness] | of about one ton of uranium in from fifty to one hundred tons of ore. The / Czechoslovakian deposits yielded only fifteen to twenty tons of uranium oxide (U30g) amnually before the war ,32 This rate of extraction could not be very greatly expanded even under strained operations—since the total reserves of the Joachimsthal region are far smaller than those of the Congo or Canada or even Colorado. The quantity of U-235 in pre-metallic uranium is only about .7 per cent (or 1/1h0th) of the whole. To be sure, plutonium239, which is equally as meee 32. See "The Distribution of Uranium in Nature," an unsigned article published in the Bulletin of the Atomic Scientists of Chicago, No. (Feb. 1, 1946), p. 6. See also U.S. Bureau of Mines: Minerals Yearbook, IGhO, p. 7663 ibid, 1943, p. 828; E, V. Ellsworth: Rare Element iinerals in Canada, Geologic Canada, 1932, p. 39. urvey of 33+ tinerals Yearbook, 1939, p. 755. 3h. Ibid., p. 828. See also A. W. Postel, The Mineral Resources of Africa, University of Pennsylvania, 19435 p. nie 39. The ifineral Industry of the British Empire and Foreign Countries, Statistical Summary, 1935-37, London, 1935, p. 4Wl9. a as