New York City Paper - Notes on the Treatment of Nickel-Cobalt Mattes at Mine La Motte

The occurrence of minerals of nickel and cobalt at Mine La Motte is probably known to every mineralogist. I will not attempt to describe these minerals, but, before entering on my subject, will briefly mention the ores, etc., which call for metallurgical treatment and enter into the composition of our mattes. Our staple lead-ore, the dressed galena, is the chief source of nickel and cobalt. It carries but a small percentage of these metals, viz.: 0.2 to 0.3 percent. usually, though when much copper pyrites is contained in the gangue, the amount of nickel and cobalt may be as great as 1.0 to 1.5 per cent. Next in importance is the ((middle product" of the dressingworks, consisting of the sulphides of iron (and copper) with gangue and galena. This usually carries 20 to 23 per cent. of lead, 0.5 to 1.0 per cent. of copper and 2.5 to 3.5 per cent. of nickel and cobalt. A larger percentage of copper always carries with it an increase of nickel and cobalt. In some few cases 12 to 15 per cent. of copper gives 6.5 to 8.0 per cent of these metals. Resides these products of the dressing-works, there is a small quantity of true nickel-cobalt-ore