stance, one like the old iron-assay furnace of Sefstroem, with blast holes at equal distances on the periphery, the very effective result of which was well known. Mr. Aubel gave an elaborate description of Raschett's furnace, alluding in the same to the cirIcular shape. By theoretical reasoning he tried to prove that a circular form does not admit of a uniform smelting region, and that the consumption of fuel in the center would be a useless one. Notwithstanding this theory, Mr. Piltz, of Freiberg, Saxony, constructed a circular furnace, 5 feet in diameter in the clear, and with eight tuyeres, which has proved very successful, and which it is now proposed to describe. For the sake of greater convenience in building, an eight-sided shape was chosen. The first furnace of this kind was built, if I am not mistaken, about four years ago, at Halsbrucke, near Freiberg. From the start, the result was so favorable and so superior to Raschett's that, with slight modifications in regard to dimensions and number of tuyeres, at this time no other furnaces are in use at Freiberg. Aubel's theory did not prove to be correct. In a properly regulated smelting operation, no so-called "pigs" are formed either in the center or elsewhere; the slag runs con The Raschette Furnace-section through the tuyeres. tinually, undisturbed by crowbar opera tions, which usually are frequently neces sary in other furnaces on account of clogging up, etc. 51 b The figures show a horizontal and vertical section of one of Piltz's furnaces. Atais represented a cast-iron box, in which the brickwork, c, is placed, and the remaining space beaten out with a composition, varying with the nature of the ore, generally being composed of one part of clay or loam and one part (volume) of charcoal, coke or anthracite, all powdered, mixed and moistened slightly. This composition is beaten in as hard as possible by means of wooden or iron pestles, and either the space is entirely filled and the crucible or receiver, b, then cut out, or the crucible is shaped during the stamping. The first method is preferable. There are two, sometimes three, tap-holes, leading the metal into the kettle, c. Above the crucible are seven tuyeres, g. The distance from g to the bottom of the hearth is 3 feet, and from g to the feeding-hole, 1, 10 feet. In case eight tuyeres are used, the last one is placed in front at i, a few inches higher than the rest, having at the same time a small inclination, so as to direct the blast to the same point in the center toward which are directed the other seven, which lie in a horizontal position. The breast, i, rests on a hollow cast-iron pipe, cooled by a constant current of water, as are the tuyeres. The upper part of the wall, k, is suspended in a cast-iron mantle. The advantage of this arrangement lies in the. convenience and facility with which the fire-bricks above the tuyeres, which are mostly exposed to the action of heat and of dissolving substances, can be removed The Piltz Furnace-horizontal section. and replaced without interfering with the upper part. Being suspended, there is also free access to the furnace from all sides. In place of the "hanging suspension," other furnaces of the kind are provided with three or more iron pillars on which the upper masonry rests. The height above the tuyeres differs often greatly up to 20 feet. The section of the furnace widens always toward the feeding-hole, as this has a beneficial effect on the result of smelting. The force of the blast, finding a larger space in the upper region, is diminished as well as the heat, and the ore dust carried out does not amount to more than 1 per cent. The feeding aperture is at l. The gases, etc., enter dust-chambers before escaping through the chimney. One of these furnaces is attended by one smelter, two slag-wheelers and three men to feed. Ore and fuel are regularly charged. The metal is tapped, from 18 to 20 times in 24 hours, into one of the two or three tap-kettles alternately. The slag runs continually into a slag-pot of cast iron of a pyramidal shape, the base being up. This cone is 29 inches high and 22 inches in diameter on the top. Matte, or globules of metal sink through the yet liquid slag to the bottom, in case any should be carried out. When stiff, the pot is turned over, the end of the slag-cone (where the metal or matte collects) broken off and melted over with the ore. The blast or quantity of wind required is not very great-for each nozzle, about 125 cubic feet per minute, or for seven tuyeres 875 cubic feet, at a pressure of 1 inch .quicksilver. In the year 1868, a Piltz furnace, 20 feet high, smelted in 28 days: Lead ores.. Tons. 545.00 50.30 The slag contained 1.56 per cent. of lead and 0.71 oz. of silver per ton. The above 1,219 tons of smelting material (which are put into the furnace mixed together) consumed 109.8 tons of coke, (middling quality,) or 9 per cent., while the old Freiberg double-furnaces consumed 14 per cent., and other furnaces 20 per cent. and over. According to the census returns the mines and smelting works at Eureka produced up to June 1, 1870, the following: Eureka Consolidated Company, with 25 men, in six months. Page & Corwin, (milling ores,) with 20 men, in twelve months.. $295,000 50,000 120,000 135,000 600,000 Total... This is, however, the product of seven furnaces and one mine, which sends her ores to Reno and Austin to be amalgamated; and of only a part of the year. The actual yield of the Eureka mines for the calendar year 1870 is not less than $1,200,000. Toward the latter part of the fall Messrs. Ogden & Dunne commenced the construction of cupelling works at Eureka, which were expected to be ready for work in December. The yield of the district increased steadily, and the bustle of active and prosperous business was apparent on all sides. In October, the Eureka Consolidated produced 222 tons bullion, worth $300 per tou. The two Buttercup furnaces produced 6 tons bullion per day. The Jackson Company's furnaces produced in October 923 tons bullion, worth $350 per ton. In the mean time new mines were discovered continually in the neighborhood, and at present it may be truly asserted that Eureka is one of the foremost districts on the Pacific slope. This view is supported not only by the number of good mines already known, but principally by the fact that these mines carry base metal ores, which all over the globe have been found to be the most permanent. The total population of Lander County, according to the late census, is 2,815; 218 of which are Chinese. NYE COUNTY. Silver Bend or Philadelphia district, which attracted so large a share of the attention of mining men a few years ago, and was soon after almost deserted, has taken a fresh start during the last year. This is principally due to the Transylvania and El Dorado lodes, from both of which rich ore has been extracted and worked, partly at Belmont, in Mr. Canfield's 10-stamp mill, and partly at Austin, in the Manhattan Mill. The Combination mill and mines have been idle. The. Arizona and the northern extension of the El Dorado are spoken of as rich mines, but, so far as I am informed, work has not yet been resumed on them. The El Dorado South is described by Mr. W. F. Leon, the agent of the company, in a recent publication in detail. I quote his account with slight alterations: The claim is 1,000 feet lineal measurement in length, and covered by a patent from the United States Government to the present owners, making the title perfect. The property is owned by the following persons: W. F. Leon, 5334 feet, of which W. P. Buford has a small portion; Robert Mullen, 2334 feet; and C. F. Singletary, 2334 feet. The mining department is under the immediate supervision of Mr. Robert Mullen. As the value and importance of a mineral property depends so much or entirely upon the quantity and quality of the supply of ore, a closely detailed description of the El Dorado South lode cannot prove otherwise than interesting and acceptable to all parties engaged in mining. The deposits occur in a rather highly disturbed zone, extending in a northerly and southerly direction, with granite rocks close at hand on the west, and on the east slate and quartzite. The vein is a true fissure, and the gangue and selvage are similar in character to those of the most celebrated silver mines in Mexico, Peru, and Europe. Excepting about 250 feet at the southern extremity, the vein is plainly traceable throughout the entire property-in places by magnificent croppings, which rise three and four feet above the surface. Such outcrops are of an unusually massive character, and consist of a white, rather compact quartz, richly clouded with black and antimonial sulphurets of silver. Some of the most interesting and splendid specimens of surface silver ores are obtained from the exposed portions of the El Dorado South lode. Only a portion, however, of the vein-matter is in the solid condition represented by the prominent outcrops just described. In such solid portions of the ledge the silver most generally pervades the quartz in the form of sulphurets. Nearly the entire contents of the vein above water-level are more or less decomposed, and much of the ore occurs as chloride. The lode varies from 15 to 40 feet in width. The productive portion of the vein, the pay stratum, varies from 9 to 23 feet. It is found at times permeating the entire vein; at other times near the hanging wall. The vein has been opened at four different places along the lode for 600 feet by incline shafts and cuts. Shaft No. 1, at the northeast end, 132 feet deep; No. 2, at 80 feet south from first, 172 feet in depth; No. 3, the main incline or working shaft, 276 feet in depth, 220 feet south of No. 2; No. 4, at 300 feet from third, 60 feet deep, with cut-off 75 feet; making 640 feet of shafting. At the depth of 240 feet in the main working shaft, at water line, a level is being run north in the solid ledge which is now in 60 feet, proving it to be over 11 feet in width, so far displaying one of the finest bodies of ore ever discovered, and impregnating the whole vein; beautiful crystallizations, including metallic silver, a combination of silver and antimony, horn silver or chloride of silver, stromeyerite, sulphuret of silver, stetefeldtite, the carbonate of copper, etc. Much of the best ore is associated with the oxides of copper and iron. In such cases the percentage of silver ore is very great, amounting at times to 25 and even 30 per cent.,of the entire mass. A few assays of this body of ore have been made, varying from $53 to $1,866 per ton of 2,000 pounds. Recent reduction of ore from the solid ledge in main shaft, at water level, yielded per ton as follows: At Belmont Mill, 20 tons.. At Manhattan Mill, 63 tons 237 00 220 56 66 66 At the south workings an enormous mass of chloride ore, colored with iron, overrides the solid lode, which has worked at the mills in this place and Austin from $130 to $562 per ton. There are now on the different dump-piles 1,000 tons of first and second class ore. That being taken out from the main shaft, and added daily to the present large amount, proves the ore in sight above water line worth alone at least a quarter of a million of dollars. The improvements on this mine in the way of shafts, levels, houses, etc., have cost over $100,000, and nothing has been done but of a useful nature. At present a whim is being used for hoisting which will be replaced by steam-hoisting works recently purchased. The engine has a capacity of thirty horse-power. The policy pursued by the owners has been rather to prospect this famous lode than to seck for profit. Already over $130,000 has been the yield of ores reduced from this property, at an average of $175 per ton. After the steam-hoisting works get in motion, sinking on the ledge will be continued for permanent work, and at certain distances in depth different levels will be run north and south the entire length of the claim. So soon as the mine is properly opened reduction works of sufficient capacity will be erected to work all classes of ore taken from the mine by the company. The latter part of Mr. Leon's article expresses a sound policy, one which, if it had been followed by more mining companies in Nevada, would have prevented many an ignominious failure. Mr. Canfield intends to erect a new mill furnished with a Stetefeldt roasting furnace, at Belmont, and as soon as this is done the great mass of sixty to seventy-five dollar ore, which cannot be worked to a profit by roasting in reverberatories at Belmont, nor stand the high rates of freight to Austin to be roasted in the furnace at the Manhattan mill, will at once become available, and a great increase in the product of the district may then confidently be expected. Montezuma district seems to be destined to become of special importance. Favorable accounts with regard to this district have reached me from time to time during the year. The success of Messrs. McGlew & Dawley has notably contributed to the prosperity of the district at large. The first-mentioned gentleman was formerly connected with the Twin River Company as engineer, and is considered a very accomplished mechanic. The firm some time ago bought a 10-stamp mill, known as the Falkner, at Yankee Blade. With the help of fourteen laborers and two brick-masons they moved this mill to the Montezuma district, one hundred and forty miles, sawed 50,000 feet of lumber, put the mill, including three reverberatory furnaces, in running order, and had a retort of bullion ready to melt in just three months and two days. This is the quickest and most successful work ever done in the State of Nevada, in that line. The product from the 10-stamp mill of McGlew & Dawley, for the first month after its completion, was, according to advices from Austin, $20,000. Several new discoveries in the district are spoken of favorably. Morey district was mentioned in my last report. The further developments during the last year are given in the following letter addressed to me by Mr. D. S. Ogden, the superintendent of the principal company of the district: Agreeably to promise, I give the following statement relative to Morey district, which is mostly an extract from my report of September 1, 1870, to the company. The district is located seventy-five miles southeast of Austin, upon the eastern slope of the Hot Creek range of mountains, fifteen miles north of the village of that name. From this range there is a spur projecting in a northeasterly direction. It has a slope of 30°, terminating in a small valley. There are apparently eighteen distinct lodes, but as the hill is penetrated by tunnels it may prove that some are the extension of others, while others may be discovered, which do not show at the surface. These veins are within a belt of about 3,000 feet, divided into two smaller belts separated by a distance of 800 feet. They all belong to one company, and with the exception of two, upon the top of the mountain, are the only ones known in the district. They are mostly perpendicular lodes cropping out at intervals from the base of the hill to and over the summit of the mountain, a distance of 4,000 feet. The position of the veins is such that tunnels commencing at the ravine are constantly upon the veins while penetrating the hill and gaining depth from the surface, thereby saving all expenses of hoisting and pumping machinery with their attendant expenses, and giving drainage to 2,000 feet of stoping ground overhead to the summit of the mountain. Upon five of the mines considerable work has been done. The American Eagle has one incline of 90 feet, and another of 60 feet, with three levels of 60 feet. The pay ore averages one foot in width at the surface and 18 inches in the bottom of the incline. The entire ore has worked $190 per ton. The Magnolia has two inclines; one 75 feet, the other 60 feet deep. The ore at the surface was one foot wide, but at the bottom of the incline it is 24 feet. The entire ore averages $200 per ton, but the last from the lowest depth attained worked $480 per ton. The Eureka, a parallel ode, shows from the surface to 30 feet down, the depth now attained, the same character as the lastnamed mine, and the ore is of the same value. The Mount Airy has a shaft 60 feet deep. The ore at the surface was one foot, but at 30 feet down is three feet wide, having entirely displaced the vein-matter. The ore has averaged only $62 per ton, though it is apparently the same vein as the Eureka. The Cedar has one tunnel commencing at the ravine, which has penetrated the hill 230 feet. Three hundred and fifty-eight feet up the hill, and 192 feet in perpendicular height from the first, there is another tunnel of 240 feet length. Still farther up the hill and 90 feet perpendicularly above the lastnamed tunnel there is an open cut 60 feet long, and of an average depth of 16 feet. Within this cut there is an air passage to the tunnel below. The ore from this mine has averaged $260 per ton. This is the only mine now actually worked. |