Huronian geology and the Blind River (Elliot Lake) uranium deposits*

In the Blind River area Proterozoic clastic and sedimentary rocks and minor volcanic rocks (The Huronian Supergroup) uncomformably overlie and trangress northwards over dominantly granitic Archean terrane (2500 + Ma) and are intruded by Nipissing Diabase (2ll5 Ma). Later deformation and metamorphic events are recognized. The developing depositional basin was controlled by the incipient Great Lakes Tectonic Zone marginal to the Algoman Craton.
The Matinenda Formation (basal Huronian) comprises northwards-derived fluvial arkose, quartzite, and pyritic, uraniferous oligomictic conglomerate which contained in 1981 some two-thirds of Canada's uranium resources. Production to December 1981 from Elliot Lake totalled 98.3 thousand tonnes U for an average recovered grade of 0.1% U with an additional 671 tonnes U recovered by leaching at Agnew Lake. The remaining resources are at lower grades. Some thorium and yttrium have been produced. Minor amounts of gold reflect the paucity in the source area. Gold is better developed in the Huronian north of Sudbury reflecting the local source area. The conglomerate beds lie in southeasterly-striking zones controlled by basement topography down sedimentation from uraniferous Archean granite. Uraninite textures, the distribution of monazite, and local enrichment by reworking indicate a syngenetic, probably placer, origin of the mineralization. "Brannerite" has formed by solution of uranium from the margins of the uraninite grains and redeposition on the original titaniferous minerals. Penecontemporaneous volcanics may have been a source for sulphur in some of the pyrite and of trace amounts of Co, Ni and Au. Some pyrite may be detrital, some may be authigenic and some introduced. Drab coloured rocks, uranium and sulphide mineralization, the presence of hydrocarbon (thucholite) and a post-Archean regolith formed under reducing conditions have been cited as evidence of an early Precambrian reducing environment extended to the atmosphere. Sedimentary features indicating fast-flowing water and possibly a cold climate imply that the uraninite would be exposed to whatever oxygen was present in the atmosphere under conditions which would inhibit complete solution. In the upper Huronian, red beds and in the Lorrain Formation a monazite - iron oxide assemblage and copper mineralization indicate more oxidizing conditions. . Similar uranium deposits occur at Agnew Lake and in the basal Huronian north of Sudbury there are minor uranium and gold values.
Provenance, lack of complete oxidation, transportation and depositional processes, redistribution during diagenesis and possibly low grade metamorphism, and the lack of postdepositional destructive processes are the dominant factors in the formation and preservation of the ores. The modified placer theory of genesis is well entrenched and an exploration model for such deposits throughout the world is well-documented. Research continues on mineralogy and textures of the ores, detailed sedimentology of the ores and their host rocks, with particular emphasis on: provenance area, the influence of early Precambrian mineralization patterns on the mineralization present in the Huronian both in space and in time, fluvial sedimentation and diagenesis. Expansion and reopening of the mines of the Elliot Lake camp should facilitate further studies.
Keywords: Uranium, Uranium exploration, geology, Blind River, metamorphism
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Publication: Special Volume
Author(s): D. S. ROBERTSON, T. P. PODOLSKY and G. E. NUTTER
Keywords: Uranium, Conglomerate, conglomerate-hosted deposits, geology
Issue: 1986
Volume: SV 33
Year: 1986
Text
Publication: Special Volume
Author(s): DAVID S. ROBERTSON Toronto, Ontario
Keywords: Uranium, Uranium exploration
Issue: 1986
Volume: SV 33
Year: 1986
Text
Publication: Special Volume
Keywords: platinum-group elements, PGE, mineralogy, Recovery, Ores, conventional process
Issue: 1986
Volume: SV 33
Year: 1986
Text
Summary: Uranium, thorium and yttrium have been recovered, since the 1950s, from pyritic quartz-pebble conglomerates occurring in the basal sediments of the Quirke syncline at Elliot Lake. Gold, an element of interest in similar type deposits occurring worldwide, is a very minor constituent of the Elliot Lake conglomerates because the provenance area of the sediments had few gold-bearing rocks.
Uranium, thorium and rare elements are found in resistate and diagenetic minerals occurring in the matrix of...
Publication: Special Volume
Author(s): F.Q. BARNES, Consulting Geologist
Keywords: Uranium, Uranium exploration, Elliot Lake, Quirke syncline, milling
Issue: 1986
Volume: SV 33
Year: 1986
Text
Summary: The Agnew Lake uranium deposits were discovered in 1953 following the discovery of the Elliot Lake deposits to the west. The original property was optioned to Kerr Addison Mines Limited who added additional claims by staking. Agnew Lake Mines Limited was incorporated in 1967 to develop the property and a shaft was sunk to 1040 metres and five levels developed before work was suspended due to low uranium prices at the end of 1970.
In 1974-75 the mine was dewatered and production started in...
Publication: Special Volume
Author(s): C.K. WILTON, Senior Development Geologist, Kerr Addison Mines Limited
Keywords: Uranium, Uranium exploration, Geology, Agnew Lake Mine
Issue: 1986
Volume: SV 33
Year: 1986
Text
Summary: The Pronto Mine located at the east end of Lake Lauzon, Long Township, some 12 miles east of Blind River is of historic note being the discovery locality and the first producing mine of the Elliot Lake uranium camp. Radioactive bedrock was discovered in 1949, a commercial deposit was verified in 1953 and production commenced in 1955. Production continued to April 1960: total tons milled 2,264,404 from which 4,643,835 pounds U,O, were recovered at a recovered grade of 2.05 pounds U,O. per...
Publication: Special Volume
Author(s): JAMES A. ROBERTSON Policy Advisor, Mineral Resources Branch Ontario Ministry of Natural Resources,** Queen's Park Toronto, Ontario
Keywords: Uranium, Uranium exploration, Pronto Mine, Elliot Lake, Radioactive bedrock, ore grade mineralization
Issue: 1986
Volume: SV 33
Year: 1986
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