Show metallurgical metallurgy cal progress in in montana by L 0 HOWARD in smelting smelling sm elting the A montana fontana copper ores the three smelt eries at anaconda butte and great falls have kept up their usual pace at anaconda many improvements have i been made in both concentrator and the recently developed great falls type of converter the 20 foot type has been installed A new plant is in course of construction st to house the improved cottrell system of electrical smoke precipitation which will take all the smoke from the roaster plant in connection with concentration at the washoe plant construction was begun early in the year on an 80 ton leaching plant to treat the tailings from the mill one 20 foot mcdougall and two 32 foot by 12 foot leaching tanks were put in and it is said that the plant has given excellent results the tailings are given an oxidizing roast in modified mcdougalle McDoug alls with two fire boxes so arranged that the flame is directed on the third floor from the top temperatures from 1000 to 1200 degrees fahrenheit are used the roasted material is leached beached with a solution containing 8 per cent sulphuric acid and 10 per cent salt two and one half hours complete the treatment costs for coal acid and salt are given as and with per cent recovery of silver and per cent recovery of copper the total cost is about 70 cents a ton the method of precipitation has not been definitely decided upon at last reports for treating the slimes a new plant is nearly erected the building being feet long and 66 feet wide four stories high and containing tons of steel the year has seen the development of the 20 deck round table and the application of a four deck shallow dorr thickener for thickening slimes and these will be part of the new installation this plant will have a capacity of 2000 tons it has been decided to cease shipment of low grade ores to the great falls plant ot of the anaconda company and to save the heavy freight charges by utilizing the short haul over the companas comp anys own electrified butte anaconda pacific railway to the plant after the first of may it is expected that first class ore alone will go ito to great palls falls the capacity of the anaconda concentrator is to be brought up to 1 tons 1 the slimes concentrates are to be dried in twelve furnaces resembling the wedge in a plant now being erected below the anaconda works improvements at great falls at great falls the building proper mr has been erected and enclosed two of the new hot stove types of ies 19 feet by feet with 33 foot arch have been put in they are unique in having no buck staves but are supported by extra wide walls they are erected on thirteen feet of poured slag through which is a 54 inch by 60 unchair inoh ai duct bringing heated air to the front of the furnace from hot blast stoves at the back these stoves are 16 feet by 40 feet the build will house five of these ies in the blast furnace department tour four 21 foot 6 inch furnaces having the great width of eight feet at the have been installed and are operating on the same blast as the conver converters tors eight pounds a unique development twelve new roasters asters ro are to be put up for the re verber atory plant in the spring the old mcdougall plant has been dismantled except for four furnaces now in use the new converter stands 21 feet 6 inches are being erected two are up and a third under way the new has been built on the same site as the old going up over the old while the latter was in operation the site formerly occupied by the gas producers is now als also 0 utilized for smelting smelling sm elting experiments completed during the year gave interesting results in increased efficiency of ro asters the development resulted in an improved furnace having concrete hearths and producing less dust all this is done without building new or enlarging the old furnaces IF R corwin and S S rodgers Kod gers in a paper printed in the july bulletin of the american institute of mining engineers give some enlightening comparisons of operations in april 1910 and april 1913 with an average of only 79 furnaces operating in 1913 more material was treated than with furnaces in 1910 and the saving in labor amounted to three furna cemen and three laborers per day and 56 5 6 feeder leaching operations leaching operations have continued at the Dull whacker and butte and duluth plants the latter leaches in sulphuric acid after grinding to eight or ten mesh using a countercurrent system through an extra long dorr classifier by this system it is claimed that a better extraction of copper is obtained with less solution of foreign elements the Buil whacker is also leaching with sulphuric acid both plants use electrolytic precipitation and cost is figured from seven to nine cents per pound of copper in connection with the concentration end of metallurgical operations especial attention should be given to the great work of the butte and superior with the minerals separation flotation process on its zinc ores and the recovery of over 90 per cent which it has obtained regularly during the past few months since this development has been treated treat edat at some length in other articles in this issue I 1 will not repeat a description crip tion of plant and results at this time |