The number of mills running on ores extracted from the Comstock Lode is seventy-six, scattered through Storey, Lyon, Ormsby, and Washoe Counties. For information relative to their details, see the "Table of Mills" in another part of this report. The process of reduction and amalgamation employed by them varies only in minor details. They are, without exception, wet-crushing mills, the Central Mill in Virginia having recently adopted this method, and Dall's Mill, in Washoe Valley, was unfortunately destroyed by fire only a short time since. These used to be dry-crushing mills, and were employed in beneficiating the richer class of ores from the Comstock Lode. The latter mill was one of the finest in the State. The raw ore is ground and amalgamated, after crushing, in iron pans of various forms, among which may be mentioned Knox's, Varney's, Hepburn's, and Wheeler's patents. The capacity of these pans varies from 400 to 1000 pounds per charge, and the time consumed in the reduction of each charge ranges from four to six hours. In a future issue it is proposed to give figures and descriptions of the different pans, concentrators, crushers, etc., in use in the State, with the results obtained in practice, and the means by which they are attained. The mills are expected to return in bullion 65 per cent. of the assay value of the pulp, which may be taken as the average working result of the district. There is thus an annual loss of 35 per cent., or about $8,000,000. In view of this fact, would it not be policy on the part of our State Government to offer a large reward for the discovery of such improvements in the reduction of ores as would enable us to save 90 per cent. of their assay value, provided it can be accomplished without consuming the whole of the additional 25 per cent. saved? The annual loss of gold and silver is more than sufficient to cover the cost of the extraction of ore from the vein every year. In the Table of Minerals Found in Nevada, under the head of "Gold," will be found information relative to the proportion of gold and silver in the ores of the Comstock vein. The cost of milling the ordinary ores of the district may be set down at $12 to $15, and the following table will show their average yield: Under this heading will be found three tables, viz: First.-Table of the products of some of the principal mines in Virginia and Gold Hill; also, showing dividends paid and assessments levied on the same. (San Francisco Stock Reports.) Second.-Bullion shipped from Virginia and Gold Hill, Nevada, for 1865 and 1866, by Wells, Fargo & Co. Third. Estimated bullion produce of Nevada for 1866. An examination of the first table will show that eleven productive mines yielded $11,261,741. Of this sum, seven mines produced $9,631,118, yielding a net profit, after deducting assessments levied during the year, of $1,614,400, or about 163 per cent. of the gross yield. The other tables speak for themselves; but it should be remembered that the dividends enumerated in the first table do not show the entire profits of the year. Many of the valuable claims in Gold Hill are private property, and their yield does not, in consequence, come before the public. The excess in the shipment of bullion from Gold Hill in 1866 over 1865, is explained by the establishment of assay offices in that place. Formerly the chief part of the crude bullion was taken to Virginia to be melted, and then shipped from the express office in that city. This is the average yield of ore from July 1st, 1860, to November 30th, 1866. (See Yield of the Mine in another portion of the report.) |