Cretaceous fluvial strata in the Moose River Basin of Ontario, Canada, as a source of kaolin for paper and ceramic industries

Abstract

Poorly consolidated kaolin-bearing fluvial strata of the Cretaceous Mattagami Formation, underlie 7000 km 2 of the Moose River Basin of Northern Ontario. Analysis of core and logs from 95 closely spaced holes from a 1.8×1.8-km block of claims in Kipling Township confirm that the sequence is a product of deposition from low gradient anastomosed rivers in which bank stability was maintained by dense vegetation. Statistical analysis indicates a close correlation of both modal grain size and depositional facies, with chemical and physical properties. Kaolin content is highest in grey (average 60%) and light brown to white mudrocks (56%) of distal flood plain facies which were subject to a fluctuating water table. Illite content is higher in grey, black and dark brown mudrocks (ball clays) which accumulated in areas of the floodplain with more stable seasonal water levels. Medium to fine sands of levee origin contain about 14% kaolin. Channel sands and gravels, have the lowest concentration of kaolin (9%), produced by in situ diagenetic alteration of feldspars by acidic oxygenated ground water in a tropical to sub-tropical climatic setting. The high reflectance of kaolin in the channel facies makes it highly suitable as a filler in the production of fine paper. The claim block examined contains the only known area in the Moose River Basin which is underlain by kaolin bearing strata, which is both near to an existing road and more than 120 m away from a major river, and has an overburden thickness of less than 30 m. Based on these constraints, the southeast part of the claim block is estimated to contain about 73 million tonnes of surface minable kaolinitic ore within about 57 m of the surface, with a stripping ratio of 0.5:1. The ore contains about 19 million tonnes of kaolin of which 5.5 Mt is suitable for use as filler in the paper industry, while the remaining 13.3 Mt could be utilized in the production of ball clays. While the ultimate scientific reserves in the basin may be in the order of 7.9×10 11 tonnes, most of this is too deeply buried and inaccessible to be extracted at this time.