| Abstract | Canada is ranked 9th in world iron ore production (2007), and iron ore is one of its most important mineral products in terms of both tonnage (31.3 Mt in 2008) and value ($2427M in 2008). Most (>95%) of
Canadafs iron production comes from iron formation (IF) deposits that were formed by precipitation on a paleoseafloor. The IF deposits are classified in two main types, based on their geological characteristics: 1) gAlgoma-typeh IF that are
intra-cratonic; and 2) gLake Superiortypeh IF, the type ranges in Michigan and Minnesota and the Gunflint in Ontario, occur on Paleoproterozoic craton margins, continental shelves and shallow rift basins.
Algoma-type IF (ATIF) formed in volcanic
arcs and rift basins of Archean to Paleozoic age. Important Canadian examples include: Ontario: Wawa iron ranges; Steep Rock iron ranges; Moose Mountain mine, Capreol; Sherman mine, Temagami; Adams mine, Kirkland Lake; Griffith mine range, Red Lake;
several ranges near Lake St. Joseph; Quebec: Great Whale iron range; Nunavut: Roche Bay, and Mary River iron range. Lake Superior-type IF (LSTIF) are generally formed on Paleoproterozoic craton margins, marine continental shelves, and shallow rift
basins, and are typically thicker and more extensive than ATIF. The most important Canadian examples are situated along the eastern margin of the Superior Craton, in the Labrador Trough (LT) that extends roughly N-S through Quebec and Labrador, and
where world-class deposits have been mined for over 55 years. Here, IF occurs discontinuously for the entire .1100 km-long distance, and extends into the Grenville Province to .300 km of the St. Lawrence River. The metamorphic grade of the deposits
and enclosing rocks is variable, ranging from amphibolite in the north and south, to greenschist in the central part. Important mining locales (or significant deposits for beneficiation) include (N to S): Payne Bay/Ford Lake/Leaf Bay areas; Cambrien
Lake; Wakuach Lake; Knob Lake-Dyke Lake-Schefferville iron ranges; Wabush Lake; Mount Wright; Mount Reed-Lac Jeannine; Sechelle iron range. Outside of the LT, notable craton marginal examples are at: Cape Smith Fold Belt; Belcher and Nastapokan
Islands; Sutton Lake Outlier; Gunflint iron ranges; Albanel-Temiscamie Basin. A third, minor type are Rapitan-type IF of Neoproterozoic age, and the best Canadian example is the giant Crest deposit, straddling the YT-NT border, that formed in a
rifted margin setting during glacial retreat. Several notable IF deposits that are being evaluated or developed include: the LabMag, KeMag, Bloom Lake, and Otelnuk Lake projects, several direct shipping ore projects in the vicinity of Schefferville
(all in the LT), and the Mary River (Baffin Island) and Roche Bay (Melville Peninsula) projects (NU). |