Show OF LO LOW GRADE ADE COPPER ORES by JOSEPH IRVING As the of low grade copper ores and compounds is attracting a good deal of attention at present and many inquiries as to the suitability of copper leaching as a commercial factor are being discussed it may be well to remember that the leaching of copper ores has been successfully cess fully practiced in europe for many years we have the immense cementation piles at rio tinto tharsis thansis Th and other points in the south of spain where millions of tons of low grade ores two per cent copper are under treatment which are a continual source of profit to the various companies which are able to take advantage of this mode of treatment ores which are too poor or are too for shipping purposes are best adapted to this form of local treatment are laid down first to a height of two feet the reason for which will readily suggest itself the rest of the ore is now piled on this prepared base and should contal contain n about ten per cent of pieces larger than two inches and about forty per cent of one inch size the remainder being the usual run of fines or smalls this may be carried to a height of even thirty feet the surface should have a slight dip of one in and should be arranged and divided into shallow basins about twenty feet square and not more than a foot deep the water coming from the mine or from a reservoir As mixed with a fair proportion of the waste or tall tail end liquor as in certain classes of ores this latter is of immense advantage and is led on the pile and distributed cautiously over one part of it for some days a dmd small proportion only of the copper being placed in an appropriate concrete tank which helps to reduce the excess of ferric salts and so on to a common settling tank the copper liquors are then run through a series of tanks canals or flip blumes flumes mes containing pig iron and scrap which precipitates the copper in metallic form the iron going off in solution as ferrous sulp sulphate liate concrete tanks having a slight slope on the floor are generally used at the top end of the precipitation system where the copper liquors are strongest these tanks are twenty feet by ten feet by three feet deep they are generally filled for three quarters of their length and all their width with pig iron laid on timbers six inches above the floo the tank and piled in regular castle form with some scrap on top about twenty tons of iron in each tank the space at the lower end of the tank is used for 0 TW T W 16 I 1 4 IV 0 T 41 Y 7 46 A cementation plies piles and canals south of spain showing arrangement fo for precipitation canals and distributing iron south of spain an easy for drainage purposes is first selected the floor for receiving the ores to be treated is prepared and hardened cu lverts two feet high and twelve to eighteen inches in width are laid with intervening cross lverts culverts cu so that all drainage from the heaps will run in one direction towards a common settling tank these cu lverts are made from large pieces of the poor ore which has been laid aid aside for cementation purposes and thus serve a double purpose chimneys are also erected at various cross section points of these lverts culverts cu so that a current of air may be maintains maint aind throughout the heap and assisted the ore to be treated is now brought forward larger pieces metallurgical engineer salt lake city ered at this time and is then diverted to another portion of the heap so that the place which has been watered may now have a chance to cook the heat developed at this stage is not allowed to exceed degrees fahrenheit Pahren heit and when it gets near this figure the chimneys are closed and the heat allo allowed weil to spread throughout the pile or heap when the cooked portion of the heap is washed again the greater part of the copper present will be dissolved out the divisions on the surface of the heap are then leveled out and the position of the basins asins Ta or squares shifted so that fresh portions of the heap are laid open for treatment the resultant copper liquors from the above operation are led by a main channel through a filter bed of clean pyrite smalls collecting the copper precipitate which is washed cashed off the pig iron and scrap the copper liquor passes through these tanks in a steady flow entering by a channel at the upper end and being diverted so as to fall to the bottom of the tank iid and rise to the overflow which is little lower than the entrance channel care being taken always to keep the iron covered the liquor is then led into a series of canals three feet by one in section which have a dip running from 1 in to 1 in 50 and are laid out in sets of two at least in zigzag zig zag fashion on the side of a hill tle te liquor passing through thern them and running off at the last with only a trace of copper it is better to have a trace in the tail end liquors as that shows that iron is not being anne unnecessarily cessa rily consumed the extra dip at the lower end of the system is also to prevent unnecessary consumption of iron these tanks and canals are arranged in a series so that the work of precipitation is never stopped and when one portion of the system is being cleaned the liquors are still at work on the iron in the other portion when the cleaning is finished the liquors are partly diverted and the cleaned portion is filled up again and set going in this manner the whole system is kept in continual active operation one of the illustrations show the arrangement of these canals clearly only concrete and wood are used in manufacture of tanks and canals no iron being bein used not even in the shape of nails where nails are necessary copper ones are used the canals are made of three inch pine lied held together by dowel pins every ade is carefully painted with hot pitch and all seams are caulked caulker with oakum and pitched consumption of iron can be brought down as low as iron to one of copper A ar precipitation system showing arrangements fo for r leaching ore in place south of spain and need not with ordinary care go above iron to one copper the copper precipitate is now cleaned by jigging which separates the leaf copper from the granular product and at the same time gets rid of iron oxides and scale the product when ready for the market will run from 80 per cent to 90 per cent copper which is finally smelted smelter in a furnace and ingot copper of per p er cent produced at one smelting smelling sm elting it may be mentioned here that leaching lea ching in situ or treating ore in place has long been practiced at various places in spain and with undoubted success one of the illustrations shows such an arrangement the retention wall shown ader u ader the bridge as a rule kept the river in place when it was considered advisable vi sable a plug in the wall was drawn and the water ran into the inner basin and so found its way to the mine min e by an old shaft the resultant c copper liquor lipor yas was pumped out ont at the eng engine ne in pump house hown in the foreground and led direct through the tank and canals shown near the engine house and in the center of the picture to be continued |