A grinder is to be used to reduce a siliceous ore of the feed size shown below. Laboratory tests o similar equipment indicate that the product size given below will be satisfactory, and that the grinder is approximately 8 percent efficient in converting input energy into size reduction as evidenced by an increase in surface.

It is estimated that a crusher to handle 10 short tons/hr will cost about $4000. If the crusher operates on a 24-hr basis for 300 days/yr, it is estimated that maintenance costs, overhead, and ordinary replacement costs will be about 50 percen of power costs. Electric power costs 2 cents/kwhr.

If this machine depreciates on a straight line basis and its life is estimated at 10 yr, what is the processing cost per ton of ore?