Show CYANIDE PROCESS IN THE BLACK HILLS mining review deadwood S D there are hundreds of thousands of tons of ore in lawrence county that will yield better than 6 per ton gold for years it has been a problem for constant metallurgical investigation and experiments by the most competent metallurgists and chemists as well as mechanical ch eb anical engineers to improve on chemical methods and mechanical departments in order that the cost of ore treatment may be reduced to the minimum the amenability of a large per cent of the ores of the black hills to the cyanide process has led mining men to realize the value of the low grade properties and they are certain to become great wealth producers at no distant day at present much attention is being given to the low grade ore deposits and the indefatigable miner has set about to replenish his fortune with the less glittering ore bodies that in times gone by were passed by countless prospectors within the past year cyaniding cyan iding has made a record of profits where loss would have resulted from any other known treatment A vast improvement is already noticeable and the result will be a very material increase in the annual gold output of the hills the superficial lime ore deposits of the ragged top district are perhaps the most amenable to this process the ore being very verr similar in character to that of the mercur utah ore these ores yield readily and give a high percent per cent of extraction with coarse crushing the ore deposits of crown hill squaw creek garden city blacktail sheep tail carbonate to the west and northwest of deadwood yellow greek creek strawberry and other districts to the south and east range in values from 4 to 16 per ton and like the shale ores of the squaw creek district are very amenable to this process the ores of crown hill have an open texture and will admit of coarse crushing another variety of ore is found immediately above the quartzite in the form of decomposed shale from which a good extraction can be obtained in a comparatively short time two processes are in vogue in the black hills the wet and the dry where the wet process is employed the ore is crushed in the ordinary stamp mill battery in the cyanide stock solution where the dry process is employed the ore passes pases from the crusher through the rolls and in a dry state is immersed into the cyanide solution the cyanide plants in operation in this district are extracting from 80 to 92 per cent of the value of the ore and while it is not likely that the actual cost of treatment will be much more than per ton it is reasonable to suppose that the per cent of extraction will eventually be higher the simple fact that thirteen plants ranging in capacity f from rom 30 to tons have been erected and placed in successful operation in the black hills within the past year should be sufficient to demonstrate that a large per cent of the ores of the hills are amenable to the cyanide process the large plant of the homestake Home stake mining company is not included in the list this plant has a daily adaily capacity apa sapa city of 1200 tons and was erected to treat the tail ings from the stamp mills which carry about gold per ton by comparison we find the per cent of gold saved by the different processes to be about as follows free milling ores with stamps 75 per cent smelting smelling sm elting 95 per cent chlorination about 92 per cent of the gold values cyaniding cyan iding 85 to 92 per cent of the gold and about 65 per cent of the silver the entire cost of an up to date cyanide plant in the black hills of tons daily capacity is about the following is the construction of one of the best appointed plants in the hills eighty H P boiler sixty H P engine 1 one crusher one set rolls two solution storage tanks twenty feet in diameter by ten feet deep ten leaching tanks twenty four feet in diameter by seven feet deep two gold solution tanks sixteen feet in diameter by seven feet deep four zinc boxes one each solution and vacuum pumps ore is crushed to one quarter mesh main building feet precipitating rooms feet engine room feet crusher room below is a carefully prepared estimate of the maximum cost of a cyanide plant of tons capacity per day of 24 hours LABOR PER DAY two engineers two firemen two crusher cru shermen men two men on rolls two solution men four pulp men 12 1200 00 one chemist one assayer one Ona helper 1 total the cost per ton for treating would be labor 65 55 Cy cyanide chanid anid 30 coal 30 zinc 10 repairs 10 incidentals 10 total several new cyanide plants are now in the course of construction with their completion the immense bodies of low grade ore blocked out and exposed in various properties can be readily and profitably treated at the custom plants while the expenditure of large amounts of money in these enterprises proves in itself the confidence maintained by I 1 reduction wo works owners in the great autu future re of the black hills district and they are as a rule competent judges standing in closer relation to the production of a mining district than any other class of men |