The Allard Lake ilmenite deposits lie in the northeastern part of one of the large Precambrian anorthosite masses which are exposed at intervals along the north shore of the St. Lawrence River, in Quebec. The ore bodies consist of a series of narrow dikes, irregular lenses, or sill-like bodies that appear to be genetically related to the anorthosite rocks in which they occur. The ore is a black, coarse-grained aggregate of ilmenite, which holds numerous oriented microscopic lamellae of hematite. Grade of the material classed as ore averages 32 percent TiO 2 , and 36 percent Fe.The Lac Tio deposit, discovered by Kennco Explorations, Limited in 1946, is the most important ilmenite occurrence in the Allard Lake district and represents the largest body of titanium ore of its type now known in the world. Exploration of this deposit by diamond drilling and surface work has indicated at least 125,000,000 tons of ore in a tabular body 3,600 feet long and 3,400 feet wide, occupying an areal extent of 134 acres. Excellent possibilities exist for materially increasing this tonnage by lateral exploration of the ore body itself, and by the development of several satellite deposits.An airborne magnetometer survey over approximately 1,000 square miles of the anorthosite mass revealed no previously undiscovered deposits, but served as an excellent means of screening large areas of relatively inaccessible country. Strong negative anomalies were obtained from deposits of massive ilmenite, while in most cases positive anomalies were registered over areas of disseminated ilmenite.Exploitation of the ore is proceeding rapidly, and recent production of iron and titanium dioxide-rich slag has been obtained at Sorel, Quebec.