67 chimneys; that is, the appearance of a dike is not considered an indication of the HOLMES.-The Holmes mine, 1,600 feet long, south of the Woodhouse and adjoining it, was opened in 1866. The vein is eight feet wide, and has been opened by tunnel along a length of 500 feet. The mine has a 10-stamp mill. The sulphurets contain from $300 to $1,300 per ton. The mill was washed BOSTON.-The Boston mine adjoins the Woodhouse on the north, and was worked by an eight-stamp mill in 1853, but did not pay. away afterwards. Some Mexicans are now at work on the mine, with two They obtain their rock from small rich chimneys. arrastras driven by water. QUAIL HILL.-Quail Hill, near the western line of the county, has a large deposit of auriferous talcose slate, containing seams of quartz and copper ore. It is not a well-defined vein, but the general course appears to be northwest and southeast, and the dip 60° to the northeast. The width is about 60 feet. Much of the surface has been washed in sluices, which paid at times very well. The total yield in sluices was not less than $25,000, and besides the gold 150 tons This mine is the property of a San Francisco of good copper ore were obtained. company, which is now building a 20-stamp mill and constructing a ditch 11 miles long from Salt Spring reservoir.* * Professor Silliman, in a paper read before the California Academy of Natural Sciences, said: In the search for ores of copper which occurred in California in what is now known as the copper belt of the Lower Sierras, deposits of iron rust, as they were called by the miners, were observed at numerous points far below the range of the main gold belt of the Sierras. Several of these ochraceous deposits had been previously located by prospecting miners for gold before there was any knowledge or suspicion even of the existence of ores of copper in connection with them. It was a matter of common observation that certain gulches or watercourses in the neighborhood of these rusty deposits were rich in placer gold, having been worked for gold from an early date. The search for copper in this kind of deposit was not commercially successful, although there were shipments of green and blue carbonates of copper, red oxyd, and metallic copper, to a limited extent from both the localities here referred to, (the Harpending mine in Placer county, and the Quail Hill in Calaveras,) the metal from which was known to contain a notable value of gold and silver, stated to be about $50 to the ton of ore. This search for copper has however opened up these deposits so as to display their character in a conspicuous manner. The rocks appear to have been originally talcose and chloritic schists, sometimes micaceous, enclosing masses of argillite, and of quartz, which appears to have been massive enough at certain points to assume the character of a vein, and parallel to the stratification, which has the usual northwestern strike and easterly dip of the region, All this mass of material, which at Quail Hill is certainly 300 feet wide, and possibly twice that, and with a linear extent exceeding 1,000 feet, appears to have been very highly impregnated or mineralized by sulphurets, chiefly of iron, with a portion of copper, zinc, and lead. The sulphurets have undergone almost total decomposition throughout the entire mass, leaving soft ochraceous deposits of a rusty red and yellow color, and staining the rocks with brilliant color, a peculiarity which the miners have characterized by the name of "calico rocks." This decomposition or oxydation of the sulphurets has extended to a point as low Dikes as atmospheric influences extend, or probably to a point where water is permanently found, which at Quail Hill is assumed to be about 170 feet below the outcrop of the mass. of porphyry and of other rocks commonly called intrusive are seen dividing these great ore channels in a direction conformable to the line of strike. But the decomposition which has COLLIER.-The Collier claim, one mile southeast of Quail Hill, is similar in character to the preceding mine, and has been worked in the same manner. The total yield is estimated at $10,000. It is said that if the mill at Quail Hill succeeds one will be built here. affected other portions of the ore channel appears also to have changed them, for they are found to be reduced completely to the condition of kaolin and lithromarge, or kindred alterations of feldspathic rocks. The outlines of the feldspar crystals are still easily distinguished, although the mass of the dikes is completely friable. In another paper on the mine Professor Silliman says the explorations made for copper have laid open the deposit sufficiently to disclose clearly its true nature, extent, and almost incalculable value in gold and silver. It is an ore channel, conformable like all the copper mines of the region to the line of strike of the rocks, not less, probably, than 300 feet in width, and perhaps more than twice that width. Its eastern wall is distinctly seen in the open cut, as shown in the section, dipping easterly about 70°. The western wall has never been seen, but is certainly pretty far down the slope, on the western side. The contents of this enormous channel of ore-bearing ground, so far as exposed, are entirely decomposed by chemical agency, so that they offer to the miner and geologist one of the most remarkable cases known of the total destruction of metallic sulphurets which plainly once filled the whole chasm, now converted into gossans or oxides of iron of various colors, and carbonates of copper, mingled with masses of spongy and white quartz, of talcose and chloritic rocks, rotten porphyry, heavy spar, &c., &c., all so completely changed and decayed by the causes alluded to that the entire mass yields to the pick and shovel in any direction. This extreme decay of the original contents renders the study of the mass at first a little difficult; no sulphurets of any kind remain visible to guide the eye, but in their place everywhere the results of their decomposition. The mass is evidently a gigantic vein, the main constituent of which was a highly sulphuretted quartz, holding originally iron and copper pyrites throughout its entire mass; these sulphurets, and the quartz itself, being very uniformly impregnated at all parts with gold and silver. Examined by the battea, the pan, or the horn spoon, no part of the contents of this great ore channel fails to give abundant "prospects" of gold. Even the dry cherty croppings broken from all parts of the hill, without selection, gave an ample show of gold. The gulch at the base of the hill has always yielded good washings, and does so still, the source of which is from the ores of Quail Hill. I found the gold in nearly all the varieties of mineral contents contained in the hill, showing that any attempt at selection would be useless, and that the whole of the mass must be worked as it runs, except certain layers of soft white rock, resembling kaolin, which are probably too poor in gold to pay for working. EXTENT OF EXPLORATIONS.-This mass has been opened by a cut driven 82 feet into it, beyond the line of the east wall, by an incline 57 feet long, at an angle of 38°, and by a shaft 42 feet below the cut, sunk in pursuit of copper ore. The shaft in the open cut explores the mass over 80 feet below the walls of the cut and nearly 150 feet below the crown of the hill. Another shaft, sunk 100 feet south of the open cut, opens the deposit to a total depth of 90 feet under the crown of the hill. Near Gopher Gulch is another shaft 62 feet deep, which passes into the unchanged sulphurets 25 feet, it is said, from its mouth, (this shaft has water in it now,) or about 170 feet under the hill. The position of all these openings is seen on the map; but there is a tunnel, not shown on the map, run some 70 feet into the hill, on the west side, and several hundred feet (about 350 feet) beyond the western limits of the location, in which the entire mass of the hill is still seen to be completely decomposed at that part also, the tunnel having been run by the pick alone. From this tunnel I obtained spongy quartz, which prospected well for gold; but this point is very far west of the supposed productive limits of the deposit. Numerous surface-pits have also been sunk over the hill in various places for the purpose of obtaining averages, from all of which gold prospects may be obtained in the pan. Value of the ORES.-I collected for assay and practical workings careful samples from I give here only the general results and averages, viz: (1.) The average from the three places named above was by working tests: BRUSHVILLE.-The Austin and Hathaway mine at Brushville, half a mile south of the Calaveras river, is on a similar deposit, and has been worked down to a depth of 30 feet. The owners of the mine, who reside in San Francisco, are erecting a 20-stamp steam mill. PLYMOUTH. The Plymouth mine, 2,000 feet long, at Brushville, is on a deposit similar to that at Quail Hill. Mr. Heusch, a mining engineer, who examined the mine in 1865, said: This mineral deposit may be described as a vein or belt of gold-bearing quartz imbedded in a soft decomposed talcose rock, the whole being enclosed between two nearly perpendicular walls of greenstone. The quartz, of which there is a lode of about eight feet in width, (2.) Ten (10) small samples collected at various points in the open cut, with a view to determine where the ore was richer or poorer, (the details of which are appended,) gaveGold Silver Total Assay value of same.. $17 08 5 82 22.90 24 70 (3.) A large lot of 2,843 pounds of ores collected some time since, under direction of Messrs. Attwood and Peachy, were carefully worked by Mr. Lewis Blanding, giving by working tests an average of— (4.) Averaging these three independent sets of returns, as we have for the general average An inspection of the tabulated results given in detail with this report will show that the silver is very unequally disposed, being found in greatest quantity in the incline shaft or near its mouth. If we view the results from the least favorable side, even accepting the lowest single averages as those most likely to be obtained in working in the large way, it is impossible to avoid the conclusion that the whole mass of the ores at Quail Hill, so far as explored, exceeds the average gold tenor of most of the best quartz mines of the State of California. COST AND MODE OF TREATMENT.-At Quail Hill the water-power is sufficient to move 100 stamps, as the water is delivered under an estimated pressure of about 200 feet head. The only water in all the region is at the command of the owners of Quail Hill. The reservoir has a present area of over 650 acres, and the right of flowage, by the terms of its location, of an elevation of 15 feet more than its present height. A line of survey is now being run for a ditch, estimated to be of about ten (10) miles in length, to convey the water to Quail Hill, and also of the line marking the area of flowage at an elevation 15 feet higher than the present. This reservoir fills the valley known as Salt Spring Valley. With these facilities it is estimated that the cost of treatment of the Quail Hill ores will not exceed 70 to 80 cents per ton, including the cost of extraction and delivery at mill. The mode of treatment is based on the condition of the gold, which is all free, viz: amalgamation in battery, double discharge; moderately coarse screens, No. 2 or No. 3: amalgamated copper aprons and riffles; large settlers to collect amalgam and mercury; an ample flow of pure water to aid in settling the residuum, and large slime pits to retain the tailings, are the main features. As experience in the management of the ores teaches us better methods, such improvements as are thus warranted may gradually be introduced. Blankets may form a part of the system, following the copper inclines. I would not advise an estimate of value exceeding $10 per ton, net saving, or say 40 and 50 per cent. of the demonstrated value. The residue is not lost, and the ample head and flow of water will permit the company at any future time to set up a pan mill, or any other approved mode of working over the tailings, provided the tailings are retained as herein advised, and should be found valuable. occupies the western part of the vein, while the remaining space is filled with the auriferous talcose rock, the whole forming a regular channel of gold-bearing matter of about 40 feet in width, many hundred feet in length, and doubtless many hundred feet in depth. It is in fact a wide chasm, running through a hill several hundred feet in height, and filled with auriferous quartz and other gold-bearing matter. Mr. Heusch estimated that there were, within 300 feet of the surface, in a length of 600 feet, 214,185 tons of auriferous matter that would yield $10 gross and $4 net per ton. There is a 10-stamp mill on the mine, and it began to run on the 1st of September. The estimated yield is $8 per ton, and the expense $2. LAMPHEAR. The Lamphear mine, 1,800 feet long, is two miles southeast of Mokelumne Hill, is on a vein which is four feet wide, and has been worked to a depth of 45 feet and to a length of 100 feet. Six hundred tons of rock have been worked, and some of it was quite rich. There is an eight-stamp mill on the mine. CADWALLADER MILL.-The Cadwallader mill has three stamps, was built for prospecting, and is not at work. FRENCH MILL.-The French mill, at Rich gulch, six miles east of Mokelumne Hill, was built two years ago, has 15 stamps, and is standing idle. MCGLYNN'S MILL.-McGlynn's six-stamp mill, erected at San Andreas to crush quartz, is being moved to Irvine's claim, on the old channel, to crush cement. CHEROKEE. The Cherokee mine, 1,700 feet long, west of Altaville and a quarter of a mile west of the line of the mother lode, was discovered by some placer miners, who washed the gravel and clay from the surface of a vein of decomposed quartz, and dug up the carious quartz filled with auriferous clay and washed that too. The discoverers, having taken out $27,000, sold to others, who got $9,000 and then leased it to a gentleman who obtained $30,000; and after him came a party who got out $25,000. The mine is now owned by a citizen of San Francisco, who has a 16-stamp mill now idle on it. The gold is coarse and is in pockets, and most of the rock does not yield more than $2 or $3 per ton. SAN DOMINGO.-At San Domingo a rich auriferous pocket was found in limestone, the rock yielding $1,500 per ton. After most of the gold-bearing quartz was extracted the mine was sold to a San Francisco company for $10,000. They never obtained any return for it. MURPHY'S.-At Murphy's a similar pocket was found and a mill was erected at a cost of $40,000. Although water could have been obtained in constant supply, it was driven by steam. The rich rock was soon exhausted, and the mill was sold and removed. At Murphy's there is a three-stamp mill now running, called the Valparaiso mill. At Cave City some rich rock was found, and a mill was built, but it has since been moved. At El Dorado there is a mill. CRISPIN.-The Crispin mine, 2,400 feet in length, two miles west of Murphy's, is on a vein which runs east and west and dips to the south at an angle of 80°. A shaft has been sunk to a depth of 100 feet, and drifts have been run 150 feet on the vein. The width of the lode is six feet, but the pay is confined near the surface to a very narrow seam next the hanging wall, though it widens as it goes down. The pay chimney is only 30 feet long on the surface, but at the 100-foot level the drifts have not reached the end in either direction. The walls are of slate, with a gouge of auriferous talcose slate. There is a water-wheel for pumping and hoisting, but no mill. A custom mill crushed 225 tons and obtained an average of $20 per ton. A quartz lode running northwest and southeast passes through Murphy's and Douglas Flat, and has been struck at many places by placer miners. At the surface it consists of decomposed quartz, and all along its line quartz boulders are found, and some of them have been rich. ISABEL.-The Isabel mine, about half a mile westward from Vallecito, yielded $50,000 in a single pocket. A mill was erected, but as it did not pay it was moved away, and the mine is not worked. CALAVERITAS.-The Calaveritas mill, erected about 10 years ago by a French company at a cost of $110,000, has been moved away. It never crushed a pound of quartz from the mine which it was built to work. Before it was completed the pocket supposed to represent the average richness of the vein was exhausted, and as no auriferous rock could be found afterwards, the mill had nothing to do. ALBION.-The Albion mine, in Salt Spring valley, three miles west of Copperopolis, has been worked for three years with a 10-stamp mill. The average yield is about $6 per ton, leaving very little profit. The gold coins $11 per ounce. THORPE'S.-Thorpe's mine, 600 feet long, six miles west of Angels, is on a vein which runs northwest and southeast, and is similar in its gangue to the Bovee mine. The thickness of the lode is three feet, and the yield is $10 per ton. The rock is crushed and amalgamated by two arrastras, driven by a water-wheel 24 feet in diameter. The Ratcliffe mine, 400 feet long, is two miles southwest of Angels, on the Copperopolis road. The vein is from four to six feet wide, and the rock is quartz mixed with talcose slate. This mine has been worked at intervals for three or four years, but steadily for 18 months, by one man, who throws the quartz upon the road, where it is ground fine by the heavy wagons passing over it, and then he shovels the dust into his sluice, which runs along the road, and catches the gold. This is the only lode mine worked on this plan in the State. CARPENTER.-Adjoining the Ratcliffe mine and on the same vein is the Carpenter mine, on which a five-stamp mill was erected in 1855. The mill was moved to Angels, and the mine is now lying idle. PURNELL.-The Purnell mine, 600 feet, adjoining the Carpenter, has been worked for five or six years, and a 10-stamp mill is now going up on it. SECTION VI. AMADOR COUNTY. Amador, one of the smallest mining counties of the State, and also one of the most prosperous, lies between the Mokelumne and Cosumnes rivers, extending from the summit of the Sierra to near the plain, with a length of 50 miles and an average width of 14. It owes its prosperity chiefly to the mother lode, which crosses the county about 12 miles from the western boundary, and has within three miles three mines, which have all been worked continuously for 15 years, have probably produced not less than $8,000,000, and form the most remarkable cluster of quartz mines on one vein in the State. Twelve miles further east, near Volcano, there is another rich quartz mining district, which has some peculiar features. Otherwise, the county has not much wealth. It has no great thoroughfare leading across the mountains, no place of fashionable summer resort, no productive mines of copper, no extensive hydraulic claims, few rich surface placers, and no quarries of marble or deposits of plumbago. The agriculture of the county is prosperous but not extensive. The farmers do not aim to do more than supply the home demand, except in wine, and for that there is no regular market as yet. The county has a large number of vineyards, and they are cultivated with care. Timber is abundant in the eastern part of the county, but scanty in the western. Near the eastern boundary, at an elevation of 10,000 feet above the sea, is Silver lake, a mile long and a half mile wide, surrounded by beautiful scenery. |