Show THE FARMERS MINING COMPANY description of mine operation and mill practice on prospect mountain the farmers mining company is a new corporation which bases its existence upon the famous old silver conner mine on prospect mountain five miles southwest of eureka nevada for the treatment of the ores of which a milling miling plant is now in course of construction at the head of this enterprise is george L reading keading a prominent mining operator and millman who constructed the reduction plant for the windfall mining company aso of eureka the successful operation of which led to the acquisition of the silver connor mine by the farmers company in describing the plan outlined for th the e operation of the silver connor mine and the practice to be followed in the operation of the new mill the sentinel of eureka says the mode of operating the mine will be as follows A raise will be started up from the prospect mountain tunnel this tunnel which the company has purchased cuts the ore bodies at a depth of 1100 feet being next to the sutro tunnel on the comstock the deepest adit tunnel in nevada or calif california ornia levels will be started off the raise every fifty feet and the ore dropped down to the tunnel level where it will be loaded in cars and hauled in trains of six to eight cars each to the mill As soon as the raise has reached a height of feet a small portable gravity winch will be installed and the ore lowered down instead oi of dropping it down the weight of the loaded skip going down will hoist the men and timbers in the skip on the other end and vice versa thus all men timbers tools and supplies will be landed at any height above the tunnel without the use of any power other than that of gravity owing to the fact that there is a large percentage of very finely crushed ore in the mine and as this ore interferes with the ordinary leaching process as used at the windfall mine the company has decided to adopt what is known as an all slime process the ore will be ground in the various machines so that it will all pass a mesh screen the main difference between the process as heretofore used and as it will be used here is that in all previous installations of this process the ore is worked in successive charges from one tank to another and this successive charge system involves periodical treatment in the different units of the cyaniding cyan iding art of the mill the mill as designed by mr kaeding has a continuous operation from the mill ore bins to the tailings pile the pulp having a continuous flow through the various machines of the mill the tailings being delivered in a continuous stream to the tailings pile the ob advantage of such a system is that the fillmen will not be called upon to watch the various charges to see that they do no not get too long iong or too short a treatment their work consisting merely in seeing that the various machines are kept constanty constantly running at their proper speed this will be the first mill of this type ever built but mr kaeding has submitted his plans and ideas to some of the leading cyanide experts of f the country and they have endorsed them as the operating cost per ton will me much less than in the all slime mills as at present constructed the ore at is comes from the tunnel will be d dumped over a grizzly and the fine ore will drop to the mill bin the coarse ore going to the gates crusher and from the crusher to the mill bin from the mill bins the ore is fed to three batteries of five stamps each stamps weighing pounds each owing to the high freight rates the company will install but ten of these stamps now and add the other five later from the stamp battery the ore flows to a dorr classifier this classifier extracting the sands while the fine ore overflows to a large settling tank the sands from the classified drop to a five foot by eighteen foot tube mill and are here ground fine and are pumped back to the dorr classifier for further classification the settling tank thus receives the entire mill product after it has been ground to a slime here the large amount of water with the ore is reduced by gravity settling a clear water overflow being obtained from the settling tank this clear water is returned to the mill storage tank to be used over again As the water will accumulate a certain amount of cyanide in using it the ore will really be crushed in a weak cyanide solution A mechanical collector or thickener in the bottom of the settling tank collects collect s the thick settled slime toward the center and a centrifugal pump takes it from this point and delivers it to the first of the series of two tall steel tanks here more cyanide is added and as much lime as may be necessary to neutralize the contained acid and the whole is agitated continually by means of compressed air introduced at the bottom of the tank the overflow from this first tank discharges continuously to the second tank where the operation is continued and the overflow from the second tank discharges continuously to an oliver filter this filter is a large cylinder covered with canvas and it revolves revolves continually in a tank which is filled with the pulp that discharges from the second agitator by means of a vacuum created on the inner surface of the canvas the pulp is sucked toward the outer side and deposits a cake of the dried ore about three eighths of an inch thick the slow revolution of the filter drum brings this adhering cake out of the balance of the pulp and after being washed with a spray of water the cake now dried to about 25 per cent moisture and with all of the recoverable gold and silver contents extracted is scraped off the other side of the drum and falls to a continuous running belt conveyor which delivers it to the tailings pile the power to run the mill will be supplied by a horse power reynolds corliss steam engine taking steam from a battery of two 70 horse power boilers the mill and mine buildings and the tunel bunel will be lighted by electricity |