fast approaching their economical limit of application in these mines. In a foot note to my previous report, (page 52,) I pointed out the great advantage of utilizing the enormous "head" afforded by the depth of the shafts, in the employment of hydraulic power. This is not possible until an outlet is created below for the water so employed; and this consideration alone renders the construction of a deep tunnel an economical necessity. It is reported that operations have been commenced on the Sutro Tunnel, and that the laboring miners themselves have subscribed a large sum, "as a first installment," toward the enterprise. Whoever builds this tunnel, it seems to be of vital importance to the industry of mining on the Comstock that it should be completed. The calculation, quoted in my last report, that fifty gallons of water per second, with a fall of two thousand feet, create a working capacity of 1,800 horse power, is slightly exaggerated, as the power thus created would be more exactly 1,516 horse-power; but the fact remains as a forcible argument, justifying my assertion that "if the Sutro Tunnel is completed to the lode, and connected with deep shafts, the conditions for explorations to still greater depths will be more favorable than they were at the very surface; since the immense power of the hydraulic column will be at the service of the miner."

MINES ON THE CONTINUATIONS OF THE COMSTOCK.

So many of the Comstock mines proper have been compelled to extract from their old workings ores once cast aside, as not worth enough to pay for treatment, that the mills, as well as the mines, have found their advantage in reducing the prices of custom-work, to enable these operations to be continued; and this reduction of prices has in turn caused the resumption of active work on many a mining claim beyond the limits of the recognized Comstock ledge, though on the extensions north and south of its supposed course. South of the Overmann are three or four claims which have lain idle for years. Under the present favorably low milling rates, ore is extracted from them on contract by small companies of miners. It is principally found near the surface, contains a comparatively large proportion of gold, and yields from $11 to $14 a ton. The amount thus obtained is, however, quite limited. North of the Utah, work has been done for some time ou small claims; and, it is said, with profit. There are a good many places on and around the Comstock lodes where it would not pay a large company to operate, but where small associations of miners, not burdened with costly organizations and administrations, can labor with profit.

The Sacramento mine appears to occupy the northern continuation of the Comstock; and in this mine a larger amount of work has been performed than in any other of the similar locations coming under this head. The ores run as high as $20 per ton, and may be called, on the average, twelve-dollar mill rock; the mean production is 50 tons per day.

A gallon of water contains 231 inches, and weighs 8.3388822 avoirdupois pounds To compute the power of a fall of water, it is necessary to multiply the amount in pounds falling per minute, by the height in feet through which it falls. The product is the number of foot-pounds per minute exerted by the fall. As 33,000 foot-pounds per minute constitute one horse-power, it is easy to obtain the number of horse-powers.

50X60X8.3388822×2000

33,000 tion as above supposed.

1,516.16 horse-powers, exerted by the column of water in mo

PRODUCING MINES OUTSIDE OF THE COMSTOCK.

West of the Comstock, very little prospecting work has been done during the year. The explorations of former seasons, upon the small parallel quartz veins in the syenite of the west wall, were not encouraging in their results, and have not been, to any considerable extent, renewed or continued.

On the contact vein to the eastward, (see last year's report, page 50,) operations have been successfully prosecuted, especially since the reduc tion of milling rates. The aggregate length of the locations on this vein amounts to three miles; but only four or five of the claims have been worked of late with vigor. The principal mines are the Occidental, St. George, Lady Bryan, Monte Christo, and Flowery. All of these, and especially the Occidental and Flowery, contain a large amount of lowgrade ore. The ground of the Occidental has been explored to the depth of nearly seven hundred feet, yielding low-grade ore (average $14) all the way down. The lower tunnel (referred to in my last report, page 50) has reached the vein 863 feet below the outcrop and given evidence that the ore is continuous in depth. The company has the promise, in the ground already opened, of eighteen months or two years of lucrative activity.

The Flowery mine has only recently (i. e., during the summer) become the scene of renewed operations. The ores vary from $10 to $28 in value per ton, and are easy of reduction by the Washoe process. The principal matrix of the vein in this mine is quartz, while the southern part, especially in the Occidental, shows predominant lime.

The contact vein upon which these mines are situated will undoubtedly yield much more ore and bullion than has heretofore been expected of it. The extended and healthy activity here springing up is a proof of the wisdom of reducing the custom rates at the mills, without which measure these mines could not have been worked. Now that the completion of the railroad to Carson is carrying in that direction the Comstock ores, the mills in and about Virginia, which would otherwise be left without employment, find in these mines fortunate sources of supply already open.

Estimate of cost of mining and reducing ores in Virginia district, Storey County, Nevada, July 1, 1869.

Wages of first-class miners: Four dollars for eight hours' work.

Wages of second-class miners: Three dollars and fifty cents for eight hours' work. Wages of surface laborers: Three dollars to three dollars and fifty cents for ten hours' work.

Cost of lumber: Common boards, three and one-half cents per foot.

Cost of mining timber: Hewed, thirty dollars per thousand feet; sawed, twentyeight dollars per thousand feet; planking, twenty-seven dollars. Cost of common powder: Three to four cents per pound.

Cost of giant powder: One dollar and fifty cents per pound.

Cost of quicksilver: Sixty-three cents per pound.

Cost of freight from Rheno to Virginia: From sixty to seventy-five cents per hundred pounds, in summer; from eighty-seven cents to one dollar and twelve cents, in

winter.

Cost of fuel: Nut pine, sixteen to seventeen dollars; cedar, eight to eleven dollars in Virginia; (cost in Gold Hill is a trifle less;) yellow pine, from fourteen to fifteen dollars per cord.

Cost of ten-stamp mill, including freight and erection: Thirty-five thousand dollars.* Cost of twenty-stamp mill, including freight and erection: Sixty thousand dollars.* * California pattern does not exist here, because California pattern has no pans. The above estimate is made for pan-amalgamation and taken from actual figures of costs.

Minimum mining cost per ton of ore: Three dollars and seventy-six cents.
Mine from which this is reported: Chollar Potosi mine.

Character of rock at that mine: Blasting rock mostly, (silver and gold.)
Depth of mine: Deepest ore extracted is three hundred and sixty feet; mostly
two hundred and sixty feet deep and less; while the depth of new shaft is one
thousand two hundred and twenty-five feet.

Maximum mining cost per ton, (accessory work included :) Eleven dollars and sixteen cents, (as near as can be ascertained.)

Mine from which this is reported: Yellow Jacket.

Character of rock: Easy of extraction, not requiring powder.

Depth of mine: Nine hundred feet.

Minimum reduction cost: Seven dollars and sixteen cents; also, two dollars and twelve cents per ton.

Name of mill, number of stamps: Savage mill, thirty stamps; Sierra Nevada, fifteen. stamps.

Character of process employed: Wet-crushing and pan-amalgamation; wet-crushing, amalgamation in battery riffles, blankets, no pans.

Maximum milling cost: Eleven dollars and eighty-two cents.

Name of mill, and number of stamps: Rhode Island, twenty stamps.
Character of process employed: Wet-crushing and pan-amalgamation.

Average mining cost per ton: In the whole district, six dollars and fifty cents per

ton.

Average milling cost per ton: Eight dollars in the whole district for pan-amalgamation.

Average pulp assay of ore of the whole district: Forty dollars, (as close as can be ascertained.)

Average yield of ore: Sixty-eight per cent. of the fire assay.

Remarks.-The Union Mill and Mining Company crushed 170,378.682 tons of ore, at a cost of nine dollars and sixteen cents per ton, including all repairs and accessory work.

Bullion product of Virginia mining district, Storey County, Nevada, for the year from July, 1868, to July, 1869.

During the year 143 feet of shaft were sunk and about 1,000 feet of drift run.

Annual statement of the Gould & Curry, November 30, 1869.

The total assets of the company aggregate $322,392, against which there are liabilities amounting to $45,325.

One hundred and fifty thousand dollars was subscribed toward the completion of the Virginia and Truckee railroad. The amount of ore on hand at the mine, July 1, 1868, was 1,683, and on July 1, 1869, 121 tons. The ore reduced during the year amounted to 55,479 tons. The amount of ore sold was 15,363 tons. The cost of production and reduction, yield and profit of the ore reduced during the past year compares as follows with the two preceding years:

The amount of ore reduced in 1866-'67, was 69,377 tons; in 1867-68, 84,627 tons, and