The so-called “combination method” is generally used in assaying bar copper for silver. It has been modified from time to time. Briefly outlined as now
The Bureau of the Mint of the United States Treasury maintains offices for the purchase of gold-bullion, and this paper describes an investigation to establish
Frequently in using a thermo-electric pyrometer for measuring the temperature of a furnace, a hole is drilled at the back or side of the furnace,
The object of refining copper in the reverberatory furnace is to obtain a metal which will have the highest attainable degree of malleability, ductility and
Lime Roasting is a term proposed by Ingalls for the operation of forcing air under pressure through a mixture of galena and lime at the
In the crucible-method of assaying ores for silver a certain amount of litharge is essential to supply sufficient lead to collect the precious metals. The
Experience has shown how difficult it is to obtain information regarding laboratory tests in connection with the chlorination-process for the extraction of gold from its
The methods employed in dressing the tin ore up to the required percentage of purity depend mainly on the type of ore crushed. These may
The purpose of this paper is to discuss the relative merits of the large 3 1/8-in. machine and the small mining drill 2¼-in. tappet machine
Here is a short account of the treatment of the base bullion for the recovery of lead, silver, and gold, and for the treatment of by-products.