Page 59 - The Geology and Ore Deposits of Sierra County, New Mexico - Bulletin 10

58 GEOLOGY AND ORE DEPOSITS OF SIERRA CO., N. M.
allowance for the total probable operating and overhead expense has been made, the total net value (smelter returns) of the re- coverable metals in the ore should be at least double that amount ; and in addition, there should be enough ore blocked out and it should be of such grade that the total cost of the plant can be paid back out of the operating profits in not more than three years, and preferably in one year. If the items of purchase of property, organization of the company, and plant construction costs are added to the foregoing estimate of operating expense to arrive at a total cost of producing the metals in the ore, then the net smelter returns should exceed this probable total cost by at least 50 per cent.