------------------+--------------+---------+-----------+----------- |Metallic Iron.| Sulphur.|Phosphorus.| Silica. ------------------+--------------+---------+-----------+----------- Typical Steel Ore | 59.24-2/3 |.20-2/3 | .03-2/3 | 6.17-2/3 Lake Superior | 68.48 | ---- | .053 | 2.07 Iron Mountain | 65.500 |.016 | .040 | 5.750 Snoqualmie | 68.80-8/13 |.023-4/13| .028-2/3 | 2.61-10/13 ------------------+--------------+---------+-----------+----------- This showing places the Snoqualmie ores in the front rank of American steel ores; indeed, it shows a little higher in metallic iron, and a little lower in phosphorus, than any of the others. These analyses are, of course, made from the ore proper; _i.e._, without any addition of the matrix, or gangue-rock, in which the ores are imbedded. With all magnetites of this type it is only in exceptional spots that much of the ore can be gotten, free from the enclosing rock. Under ordinary circumstances something like 20 per cent. of the ore sent to the furnace will be gangue-rock. There is reason to hope, however, that ere long there will be a practical method for separating the rock from the ore, and at the same time getting rid of most of the sulphur. At Cranberry, N. C., the ore is now roasted and stamped into small bits, and an experiment has been made of passing the ore through a jigger, whereby the hornblendic and other enclosing rocks were separated by the pulsations of the water, as in coal washing. [Sidenote: Improved processes.] The Lackawanna Iron and Coal Company, Pennsylvania, has been separating the ore from the rock with good results. The same has been done at Crown Point, N. Y., Lion Mountain, near Plattsburg, N. Y., Negaunee, Mich., and Beach Glen, N. J. The process is really one of concentration, in some respects similar to that pursued with the refractory ores of the precious and base metals. The ore is first calcined sufficiently to make it friable. It is then crushed, by a Blake or other rock-breaker, and is finally sluiced, or jigged, or both. The aim is to produce a Bessemer concentrate which would yield 60 per cent. or more metallic iron, and at the same time get rid of whatever phosphorus might be in the gangue-rock. In the best experiments the object was more than accomplished. The concentrate contained 63 per cent. of metallic iron, the middlings 55 per cent., and the tailings 16 per cent. This experiment was made with a refractory Adirondack magnetite, which was so intermixed with hornblende, quartz, mica, etc., that the ore might be described as a hornblendic gneiss, carrying a large proportion of magnetite. No doubt experience will teach some way of saving the ore that is now wasted in the tailings. Thus we may hope to see removed in a short time the only practical difficulty in working the crystalline magnetites, such as those of Snoqualmie, and many others.