Page:Popular Science Monthly Volume 50.djvu/404

388 and made to rotate to and fro until the soft sand is washed away from the ore, which is then thrown on a scow provided for the purpose or carried to shore. When a sufficient quantity has been collected it is carted to the railway near at hand and loaded on cars.

From the deeper parts of the lake the ore is raised by means of a steam dredge. The captain of the dredge moves over the lake, and, putting down a pole and working it about on the bottom, can easily learn where there is a body of ore suitable for dredging. The dredge is then moved to the desired spot and work is begun. The ore and sand are brought up in buckets on an endless chain and thrown into a long, revolving screen, adjusted and inclined so as to deliver it upon scows moored to the dredge. In its course down the screen the mixture of ore and mud is acted upon by water which is thrown upon it with considerable force.

By this means the mud and sand are washed out of the screen and the clean ore is deposited on the scows. These are towed by a steamer to the landing at the head of the lake, and the ore is transferred to cars to be conveyed to the furnace, ten miles distant.

The plant on the lake consists of the dredge, a number of scows, and a small tug, the latter being used in moving the dredge from place to place, in towing the scows, and in carrying supplies, for the crew live on the dredge from Sunday night until Saturday night, and work overtime, in order that a year's supply of ore may be raised during the summer.

The ore obtained from this lake is essentially a brown hematite—that is, hydrated peroxide of iron, with which is associated more or less organic matter. The writer has made numerous analyses of the ore, and the following is that of a sample representing a large quantity:

This lake ore, mixed with carefully selected bog ore from the adjacent district and with a certain percentage of magnetic ore, is smelted with charcoal in the Canada Iron Furnace Company's furnace at Radnor, and produces a charcoal iron (brand "C.I.F.") far superior to the iron from the Lake Superior charcoal furnaces.