Sherman Mine

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The Sherman Mine in Temagami, Ontario, 400 kilometers north of Toronto, was a major producer of iron ore. The mine was the source of a multi-ton boulder of banded iron formation and was mined from 1967 until 1990 by Cleveland- Cliffs Iron Company. This 2.2 billion year old formation consists of thin layers of sediment that were deposited in a marine environment and subsequently metamorphosed. Sherman Mine was also one of the largest open pits in Temagami until it closed in 1990.

[edit] Mineralogy

Its mineralogy records a time in the early Earth's history when the atmosphere and oceans contained significantly less oxygen then their present day counterparts. FER-3 and FER-4 are from the mine. FER-3 is from the west pit in the north limb of the Tetapaga incline, containing metavolcanic and pyroclastic rocks. Quartz is the most abundant mineral present at the mine. Hematite occurs as dusty inclusions in the quartz, but as micro-laminae in jasper layers. FER-4 was taken in the south pit from a cherty magnetite iron formation containing chloritic tuff.