largely interested in the Mineral Hill mines, are putting up works that will cost nearly $100,000 when completed. Some of the ore taken from this extraordinary hill are so exceedingly rich in gold, that a 10-stamp battery is being erected to crush the ore and work it for the gold, by the ordinary processes adopted for saving gold from quartz; the tailings will be afterwards smelted for the copper they contain, nearly 40 per cent. The gangue rock of nearly all these Arizona ores is composed of spathic iron, heavy spar and quartz; the ores found in California being free from gangue rock, though they are generally mixed with the containing slate or serpentine. Knowles & Lightner, another firm, extensively engaged in these Arizona mines, are also putting up smelting works on their ground. The Great Central company have a set of such works in active operation, and turning out large quantities of good regulus of about 80 per cent. Most of the labor done about these mines is performed by natives, Mexicans and Chinamen. Not more than one-fourth of the workmen are Americans or Europeans. Aubery City is located on the north side of the fork, and would soon become quite an important place of business if sufficient tonnage could be obtained to carry away the ore that could be furnished by the mines in its neighborhood. 3. THE GEOLOGICAL FORMATIONS IN WHICH COPPER IS FOUND. Peculiarities of formations.-There are peculiarities about the geological formations in which the copper ores are found on this coast, which derive an interest from the great extent of country over which they can be traced. For instance: Not a single important body of such ore has been found on this coast, either among the coast range, the foot-hills, or among the Sierra Nevadas, except in the immediate vicinity, if not actually in serpentine or other magnesian rocks or matamorphised slates. This is the case in all the districts above described, the only exception being at Hope valley, Amador county. For the hundreds of miles over which the great belt of copper ores can be traced, it is never found except in one or the other of these rocks, and invariably without any gangue rock, except this containing slate or serpentine. This great belt of copper ore is never formed except in the immediate vicinity of the auriferous slates and quartz. As has already been mentioned, all the copper found on this coast contains a large per cent. of gold, and many of the most important auriferous quartz lodes contain a considerable per cent. of copper ore. In some sections of the State the gold itself is so much alloyed with copper that it is not more than half as valuable as that obtained from other sections. The numerous fossils that have been discovered in both the auriferous slates and in the vicinity of the great copper belt, prove that both formations belong to the same geological era. It may therefore be reasonable to suppose that the same causes which produced the one, at the same time produced the other. The nature of these causes has not been sufficiently studied to be of any practical use; though the subject involves many important practical and scientific points, such as the compilation of facts and the observations of practical men in the department you have just inaugurated may throw much light upon. The costs of working the copper mines.-The cost of working the copper mines on this coast is, under the present system, a great impediment to the development of this source of national wealth. Expenses of copper mining are much influenced by three conditions: the convenience of the mine to the market for its product, the kind of labor employed, and the position of the mine in reference to facilities for working it. The mines at Copperopolis, which are most favorably located with reference to the convenience for sending their ores to market, pay, on an average, about per ton to carry their ore from the mine to the ship which carries it to the $8 furnaces, about $15 per ton as freight charges by these sh ton for bags in which to carry it; or $27 per ton for ca nearest market, a sum nearly equal to the average value of obtained from the mines in England and the continent of as are located further inland, or in localities removed from ma fares, have to meet additional costs for transportation. This expensive transportation compels a closer examin would otherwise be necessary, and this work has all to order to select only such of it as may be sufficiently rich to requiring considerable skill on the part of the laborers em tion costs, at a very low estimate, $1 per ton for such or and causes a waste, in some classes of ore, amounting to ter the crumbled rich ore among the slate and refuse, which is pile, for want of a ready means for its separation. The costs for bags alone, unavoidable under the present cause of the stoppage of the work on several good mines. enormous tax on the copper resources of this coast. There this system, of avoiding this expense, as shipowners will New York or Boston unless it is in bags. Occasionally, ore has been shipped to Swansea in bulk; but as it is very cargo belongs to one party, or is of one grade, it is very ra of shipment is adopted. These bags are scarcely ever quently are nearly a total loss. Meader & Co., who are la the shipping business, secure the return of a small portion they have undergone the wear and tear of a six months' vo in a damp hold of a ship, and been subjected to the rough movings, they are of comparatively small value when retu The class of laborers employed, and the wages paid f another material condition greatly influencing the costs of coast. The average wages of copper miners, American o fornia, except at Copperopolis, is about $3 per day. The the two largest companies at that place, pay $2 60 per day whether they work above or below ground. Other compar $3 per day for drifters, and $2 50 per day for all other labore panies in other portions of the State employ Chinamen a all work done above ground, who work for $1 per diem. under proper supervision, do as much work, and as well laborers, it follows that those companies that employ the: saving of expense. The owners of the Copperopolis mine this class of labor in that locality lest it might create dis miners, of whom there are about eight hundred in the valle usual with their class, have an intense hatred to the Chine not by any means allayed by the knowledge that their pres would insure a reduction in the rate of wages. It is quit duction of Chinamen to work on these mines would create ance. But it is scarcely to be expected that proprietors o lions of dollars, the returns on which depend on the econ are worked, will be deterred from availing themselves o cheapest labor in the market, through fear of the acts of It being so much to the interest of the State that eve afforded to those engaged in developing its mineral resou on the part of individuals or combinations to prevent the labor for that purpose would be severely punished. The mines in Oregon and in the northern portion of C to $3 per day for laborers. At the mines in Arizona most of the work is done b satisfied with about $30 per month and a certain quantity of provisions. There are a good many Chinese employed at these mines, who are paid $30 per month and board themselves. The Americans and Europeans employed are paid from $50 to 60 per month in addition to their board. The position of the mine, the facilities it possesses for working, is another important condition connected with the costs. Mines located in the lower level of broad valleys, such as those at Copperopolis, where they have to hoist everything taken out of the mine and to lower everything put into it by machinery, and to pump the seepage water of an extensive district from a sump-] -hole five hundred feet in depth, labor under the greatest possible disadvantage The costs of engines, their wear and tear, and the expense of their superintendence and repair, imposes a cost of more than $5 per ton on all the ores extracted from these mines. It is a fair estimate to calculate that every ton of ore taken from the Union and Keystone mines costs $16 per ton as it reaches the surface. This calculation includes the division of all the expenses attending the conduct of the business of the mine by the quantity of ore actually shipped. These figures, explaining the costs of working the copper mines when compared with those showing the value of their products, show why so many good mines have stopped work during the past year. The present price of fifteen per cent. ore at Swansea and New York is less than $50 per ton. To obtain this it costs the mines at Copperopolis This does not include any allowance for loss by broken bags or carelessness in handling after shipment, or expenses for commissions, &c. It must also be remembered that not one-half of the ore extracted from these mines will average fifteen per cent. It is known that Meader, Lalor & Co. have shipped thousands of tons of ore which did not exceed twelve per cent. These Copperopolis mines, exporting nearly three-fourths of the ore, furnish unmistakable data on which to base a calculation of the very slight margin of profits that arise from copper mining on this coast as at present conducted. There are some mines, such as La Victoire, in Mariposa county, and those in some of the northern counties and in Oregon, in which the costs of extraction of the ore does not exceed $4 per ton, as they are worked by tunnels and require no hoisting or pumping. But the cost of transportation is much greater from all these mines than it is from Copperopolis, and the quantity of fifteen-percent. ore costs more for selecting. The quantity of carbonates, silicates, and oxides obtainable in any locality in California and Oregon is so unimportant as not to come within range of calculations concerning the costs of regular mining. It cannot be possible that this present condition of affairs connected with the copper resources of the Pacific coast is without remedy, as the annexed table will show. The mines on this coast within five years of their discovery, in spite of every disadvantage of inexperience in the work of their development and want of knowledge of the nature of their ores, have exported nearly eighty thousand tons of ore, valued at the very lowest estimate at upwards of $5,000,000 A national source of wealth so productive in its infancy will not be left to die of inanition for want of the fostering care of the general government. As will be explained anon, to smelt the ores on this coast, with the present price of fuel and the metal when made, would be but a partial and ter final success of which is involved in doubt. The recomme man of the national revenue commission on this very poin effectual plan that will secure the extended development of of this coast. The following is a copy of the commission referred to: "The commission therefore recommend that domestic copper be repealed; and that the duties on impo copper be advanced to a moderate extent, or sufficient t mining interests of the United States from the depressing taxes upon their supplies, and to give to it as good a stand kets, with reference to foreign competition, as they had befo were imposed." Processes in use for smelting and concentrating the ores.been proposed and tested for the purpose of smelting and co per ores found on this coast, none of which, for causes to entirely successful, though several of them have been parti description of all these various processes, and of the furn used, while it might be both interesting and instructive, wo in this report. Most of these plans which have been tested have possessed some novel principle, which might be of ad in combination with old established processes, by those wh sary skill, experience, and judgment to admit innovations which they may have been educated. This seeming digres explain the principal cause of the failure of some of the mo have been erected for the purposes to which this portion of t not a few cases, those having charge of these works appe the impression that it was so absolutely necessary to follow troduced from their native land, that some German, French, tives seemed to attribute their failure to the fact that the and the materials used, did not understand the German, language. Early in 1862, works of an experimental character were on the banks of the San Joaquin river, near the base of Mo purpose of testing the adaptability of the coal obtained smelting purposes; many persons, supposed to be authori expressing the opinion that such coal was unsuited for the p These works were erected under the direction of Mr. Th perienced Welsh copper miner, who has for several years beer the Swansea smelters, for the purchase of copper ores on t man of considerable scientific attainments and a first-class pr metallurgist. It may be proper to state further, that this opinions on this subject of fuel should have much weight, chemistry at the most famous college on this coast, and su assaying and refining works of Kellogg, Hueston & Co., private establishment in that business in the United States. These works put up by this gentleman at Antioch consisted furnace and roasting kiln, built on the plan of those in use somewhat smaller scale, and with a slight change in the fo adapt it to the fuel. The furnace has a base of thirteen feet nine feet four inches wide, with a chimney-stack, for the sufficient draft and carrying off the fumes, sixty-five feet high were built of the best available materials. As stated above, this furnace was built as an experiment, adaptability of the Mount Diablo coal for smelting purposes-to ascertain the quality and quantity of heat it generates. 66 It would occupy too much space to enter into any extended details of the nature of this coal; but it may be necessary, to make the subject plain to those who have never paid any attention to the study of such matters, to state that in a reverberatory furnace the fire in its passage up the chimney strikes the roof, and is forced down upon the ore by means of a bridge," built between it and the burning fuel. In all flames, no matter how generated, there is one portion more intensely hot than the others. This is called the "reducing flame" because of its action in reducing ores, under certain conditions, into metals. All coals do not produce a flame of the same nature or length, and the operation of the reverberatory furnace depends, in a great measure, upon its being so constructed that the "bridge" is placed so that the reducing portion of the flame is caused to strike the ore at the proper point. After this explanation it will not require any technical or scientific knowledge of the principles of combustion to understand that a furnace to use fuel, which burns with a short flame and little smoke, requires great modifications in its construction when it is to be used to burn fuel which produces a long flame and much smoke. The experiments at Antioch settled this point clearly, if not satisfactorily, to those interested, and proves, for general information, that furnaces built on the plan of those used at Swansea, in which the short-flamed Welsh coal is used, are not adapted for the use of the long-flamed coals of the Pacific coast. But the question whether this long-flamed coal could not be used for smelting purposes, in a suitably constructed furnace, remains still unsettled Mr. Price states this Mount Diablo coal could be economically used for that purpose in a properly constructed furnace, but thinks no attempt should be made to proceed any further than in the conversion of the ores into regulus. The price of all descriptions of coal being so much higher on this coast than a better article can be obtained in other countries, the refining of the metal can be more profitably done in those countries. It is much to be regretted that the company, which expended nearly $50,000 in making these experiments at Antioch, did not carry them out to a full conclusion, by permitting Mr. Price to make such changes in the form of the furnace as his skill and experience may have suggested. But in California, where money commands from 18 to 24 per cent. interest, such experiments are not considered profitable. The first bar of metal from the Antioch smelting works was received at San Francisco on the 14th of September, 1863, and created almost as much interest as the first bar of bullion from Washoe. During the time these works were in operation they produced about 200 tons of matt, or regulus, of an average of about 50 per cent., the balance being iron, sulphur, silica, &c. This was obtained from about 2,000 tons of ores from various parts of the State, but chiefly from Copperopolis, of an average of about 10 per cent., which the company advertised to purchase at the following prices : 7 per cent... 9 per cent.... 10 per cent... 11 per cent... 12 per cent.. None were accepted below 7 per cent. $15 per ton of 2,376 pounds. 17 per ton of 2,376 pounds. 19 per ton of 2,376 pounds. 21 per ton of 2,376 pounds. 25 per ton of 2,376 pounds. The coal used in the operations cost about $7 per ton delivered on the grounds of the company. One ton of this coal, it was estimated, would reduce two tons of ore, after the furnace had become thoroughly heated; but in consequence of the difficulty in obtaining good materials for lining it the furnace was not kept steadily heated. The best imported fire-bricks, in consequence of the acH. Ex. Dǝc. 29-11 |