The Monteagle Nepheline-Corundum-Mica Deposit Hastings County, Ontario

CIM Bulletin, 1962


The deposit, which forms a ridge -adjacent to the York river, in Monteagle township, is held by Monteagle Minerals Limited, of Toronto. The ore is in a Precambrian gneiss which is composed of nephel'ne, scapolite, andesine and microcline feld spars, muscovite and biotite micas, and corundum. The major orebody is tabular and is exposed for 1,200 feet along the crest of the ridge. It averages about 90 feet in thickness, dips at about 70 ° , and was intersected by drilling at a vert'cal depth of 600 feet. The deposit was prospected for corundum in the early 1900's. Recent exploration was undertaken to determine its potential as a source of highalumina ceramic material, with byproduct corundum and white mica. The program included prospecting, mapping, trenching, diamond drilling, bulk sampling, beneficiation research, a large-scale beneficiation test, product evaluation, market investigations, and plant design. Reserves, to a depth of about 300 feet, are estimated at about 3 million tons. Further exploration, both laterally and in depth, could increase this figure. Beneficiation includes grinding to 50-mesh, separation of most of the corundum by gravity, removal of calcite and the remainder of the corundum by flotation, separation and cleaning of muscovite by flotation, flotation of biotite, and the removal of the remaining biotite and other iron-bearing minerals by high-intensity magnetic set1aration. The final products, showing the proportions recoverable in terms of original feed, .are as follows: , 55 per cent - Alumina-rich ceramic raw material. A mixture of nepheline, feldspars, and scapolite, con taining 29 per cent Al203 and 0.07 per cent Fe20 3; acceptable as a glass ingredient. 8 per cent - Muscovite mica. Pinkish white, water-ground to 88 per cent minus 325-mesh; acceptable as a paint extender and filler. 2.4 per cent-Corundum. Colour- 1ess to light blue grains; acceptable as an abrasive in the optical industry. A 67-ton sample was processed in the pilot plant of the Mines Branch in Ottawa. Ten tons of the resulting 11epheline concentrate was the sole source of fresh alumina during a week's operation of a commercial glass furnace which supplied four lines producing various types of container glassware
Keywords: biotite, Canada Corundum Company, gneisses, Monteagle Nepheline-Corundum-Mica Deposit, Nepheline. ., Concentrate, Concentrates, Corundum, Deposits, Mica, micas, Nepheline, Ore, Ores