Blind River

Palaeoplacers are placer concentrations that have occurred in the geological past and which are preserved till the present by a cover of later sedimentary rocks. The Witwatersrand gold-uranium deposits (South Africa) and the uranium deposits at Blind River (Ontario, Canada) and Jacobina (Brazil) are the most important examples of palaeoplacers. 

Amine reagents also extract thorium from carbonate solutions and the use of a primary amine, RNH3C1, where R = C10 to Cl3 alkyl, as a 20% solution in kerosene allowed the concentrations of impurities in the extracted thorium to be reduced by factors of 33.8 for UVI, 111.4 for MoVI, 18.9 for Zrlv and 6167 for Mg11.177 The extracted thorium species was shown to be of the composition (RNH3)4Th(C03)4(H20)x. Di(tridecyl)amine has been used to extract thorium from barren uranium process liquors in the Blind River plant in Canada147 and flowsheets for the recovery of lanthanides, U03 and high-purity Th(S04)2 from the Elliot Lake area in Ontario using Primene/isodecanol have been described.178... 

Ramdohr P. (1958) Die Uran-und Goldlagerstatten Witwaters-rand-Blind River District-Dominion Reef-Serra de Jacobina erzmikroskopische Untersuchungen und ein geologischer Vergleich. Abh. Deutschen Akad. Wiss Berlin 3, 1-35. 

Minerals of the third group of Table 5.15 contain relatively small proportions of tetravalent uranium combined with a refractory oxide of titanium, niobium, or tantalum. To free the uranium from these minerals, they must be leached with hot, concentrated sulfuric acid. Davidite is one of the principal ores at Radium Hill in South Australia. Brannerite is found in the Blind River district of Ontario. Pyrochlore occurs in the Lake Nipissing district of Ontario and in Nigeria. 

Thorium has been recovered as a by-product of uranium production from ores of the Blind River district in Ontario in which the uranium thorium ratio is 6 1 [C5], In such thorium the Th activity is 3.1 X 6 = 18.6 times the activity of the Th. 

A process has been described by Arden et alP for the recovery of thorium from the liquors obtained by leaching the Blind River uranium ore. The major part of the uranium is first removed by conventional anion-exchange. 

It can be used as a 0-1M solution in kerosene for the extraction of thorium from the very dilute sulphate liquors remaining after the extraction of uranium by ion-exchange. This applies particularly to the uranium ore from the Blind River area of Canada, where the thorium-to-uranium ratio may be as high as 1 4. A completely sulphate system is employed at pHl to 2 with a half saturated solution of sulphurous acid as an impurity strip. The thorium is backwashed into nitric acid or another nitrate solution. 

Di (tridecyl) amine can also be used for the extraction of thorium from the very dilute liquor left after either ion-exchange or solvent extraction of Blind River ores. For example, in a two cycle process, tri-iso-octylamine first extracts the uranium and the di (tridecyl) amine cycle is then adjusted to remove the thorium with the minimum iron contamination. The thorium is backwashed with 1M sodium chloride-0 05M sulphuric acid solution and precipitated with ammonia. 

With regard to UO2 conversion supply, Cameco s plant is by far the largest supplier, with a licensed annual capacity of 2800 tU. In addition, smaller plants exist to meet the local needs in India, Argentina, and Romania. Cameco Corporation owns and operates ma-nium refinery and conversion facilities located respectively at Blind River and Port Hope. The Blind River plant refines natural uranium concentrates (U3O8) into uranium trioxide (UO3) and was commissioned in 1983. The intermediate product is shipped to the Port Hope plant (commissioned 1984) where further processing produces natural UFg. 

DeGraw, J. (2012). June 23, 2012 Uranium contamination event and action level exceedence. Blind River, Ontario, Canada Cameco Corporation, http //www.suretenucleaire.gc.ca/ fra/pdfs/Regulatory Action/2012/20120827-cameco-report.pdf (accessed July 27,2014). 

Brannerite is the third most important reduced uranium mineral in that it occurs in many different types of deposits and is the chief uranium producer in the conglomerates of Blind River-Elliot Lake, Ontario, Canada. Although it has been found in pegmatites, hydrothermal and sedimentary deposits, it is always associated with uraninite and probably forms through reactions with uraninite and titanium phases that are also present. 

Richardson K. A. Killeen P. G. and Charbonneau B. W. Results of a reconnaissance type airborne gamma-ray sp trometer survey of the Blind River-Elliot Lake area. Pap. geol. Surv. Can. 75-lA, 1975, 133-5. 

Robertson J. A. The Blind River uranium deposits the ores and their setting. Misc. Pap. Ontario Ministry nat. Res. 65, 1976, 45 p. 

Sedimentary Quartz-pebble conglomerate Blind River-Elliot Lake (Canada)... 

Classic quartz-pebble conglomerate districts are the Blind River-Elliot Lake district, Canada, and the Witwatersrand, South Africa. Similar deposits are known in Australia, Brazil, Finland, Algeria, India, the U.S.S.R. and the U.S.A. 

Arnold R. G. A preliminary account of the mineralogy and genesis of the uraniferous conglomerate of the Blind River, Ontario. M.A.Sc. thesis. University of Toronto, 1954. 

Derry D. R. Evidence of the origin of the Blind River uranium deposits. Econ. Geol, 55, 1960, 906-27. 

McDowell J. P. The sedimentary petrology of the Mississagi quartzite in the Blind River area. Geol. Circ. Ontario Dep. Mines no. 6, 1957, 31 p. 

Robertson J. A. A review of recently acquired geological data. Blind River-Elliot Lake area. In Huronian stratigraphy and sedimentation. Spec. Pap. geol. Ass. Can. no. 12, 1973, 169-98. 

Ivermectin (Fig. 25.18) is used to treat onchocerciasis, which is a disease caused by a nematode which is transmitted via the bite of a black fly. The bite injects the larvae under the skin of the host where they mature into adults in nodules, thus evading the host s immune system. The adults mate and produce larvae which are responsible for the strong inflammatory response of the host which causes acute dermatitis, and if the larvae migrate into the cornea of the eye this causes blindness - river blindness. ... 

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