Overview

Mine Type	Underground
Status	Inactive / Suspended
Commodities	REE Uranium
Mining Method	Room-and-pillar
Mine Life	...

Deposit type

• Sedimentary

Summary:

The uranium deposits at Elliot Lake are contained in the sediments of the westward plunging (~15°) Quirke syncline. The mineralization is surrounded to the north and east by Archean granites and to the south by Archean mafic metavolcanic and metasedimentary rocks. Depth from surface to the centre of the Quirke syncline is estimated at approximately 1,500 metres.

Mineralization at Eco Ridge is contained in the conglomerate beds of the Ryan Member, which is roughly 100 metres thick and consists of quartzite of a distinctly green colour (sericite alteration) and quartzite with intercalated quartz-pebble conglomerates. The quartz-pebble conglomerate beds containing uranium and REOs are located in the west-northwest channels of the Matinenda Formation. The Ryan Member represents the lower Matinenda and is characterized by an increase in the amount of pyrite. Low-grade mineralization is generally contained within the coarser-grained quartzite beds while higher grades are contained in quartz-pebble conglomerates with disseminated pyrite. A 30-metre thick Nipissing diabase dyke strikes east-west across the entire property and cross cuts mineralization.

The reefs inside the Pardee Channel on the south limb of the Quirke syncline hold the Eco Ridge deposit. It is believed the stratigraphy of the mineralized reef in the Pardee Channel can be correlated to those of the Nordic Channel, where much of the region’s historic mining was conducted. The mineralized zones of the Nordic Channel are separated into Lower, Middle and Upper conglomerate reefs. The Lower Reef is thin and discontinuous; the Middle Reef has been the most historically mined while the Upper Reef has had more limited mining. The Upper Reef is thought to be correlated to the MCB at Eco Ridge.

The MCB and the quartzite floater reefs 6 to 15 metres above it contain the Eco Ridge mineral resources. The MCB contains quartz, quartzite and dark cherty pebble in a fine-grained, pyrite rich matrix. Uranium content is concentrated at the base of the MCB and decreases moving toward the top of the bed. The MCB ranges from 1.3 to 4.4 metres in thickness. The floater reefs are generally thinner, ranging from 0.1 to 2.0 metres in thickness, and generally contain uranium grades of less than 0.04%. The zone of quartzite with floater reefs above the MCB is referred to as the Hanging Wall Zone (HWZ). The thickness of the HWZ is variable, but U3O8 and REO grades appear relatively consistent.

Uranium mineralization in the Elliot Lake region is generally contained within uraninite and brannerite. Coffinite, thorite and an unidentified uranium silicate carry yttrium oxide (Y2O3) and Heavy REO, while monazite typically carries Light REO. It has been generally observed that there is a correlation between pyrite content and uranium (pyrite content historically being used as an ore cue) at Elliot Lake and that REO mineralization drops off less rapidly than U3O8 mineralization
above the MCB.

Mining Methods

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Comminution

Crushers and Mills

Processing

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Production