Show F T THE GODBE AGITATION CYANIDE PROCESS L written by E L godbe this is a new method of leaching ores by agitation and the separation of the gold bearing solution from the sludge it is especially adapted for ores that require to be finely pulverized or ores that slime considerably and is ostensibly a combination of percolation and agitation simultaneously in the same tank the former however being upward percolation instead of downward as in the case of the ordinary leaching operation the process is not an experiment having been thoroughly tested on a large practical scale in two ten stamp mills and every mechanical ch anical feature has been demonstrated one being the april fool mill at de lamar nevada and the other the plant of the echo mining company at mojave kern county california of which mr george H hooper formerly of this city is the president and manager the operation is carried on in rather a deep tank fitted with a stirring muller that revolves close to the bottom of the tank and while the agitation is more or less vio at the bottom it does not extend up to the top and consequently the top consists of nothing but clear settled solution the solution enters the tank at and all over the bottom through perforated pipes and flows or percolates upward through the agitated and suspended mass and rises into the clear solution zone at the top and overflows this upward percolation is continued until all the gold bearing solution has been washed out or displaced by weak precipitated preel solution and this in turn is then displaced by water when a plug is drawn and the entire charge is allowed to run out into the tailings dam the system is entirely automatic requiring no shoveling or of sands or slimes and has been proven to be far superior to any percolation settlement and decantation filter pressing or any other method so far known of treating climey ores both as regards cost of operation and last but not least the extraction and recovery of the values from the ores A brief description of the modus operandi operand of this process and the results obtained at the echo and april fool mills will suffice to illustrate something of its practical operation and also the very efficient work done the echo ore is ground through a 35 mesh screen in a stamp battery with a solution of cyanide of 05 per cent strong and is passed over silver plated copper plates and from there to the tanks of which there are six that are eleven feet in diameter and twelve feet deep each fitted with a revolving stirrer stirred about six parts of solution to one of ore is used in crushing and it takes about four hours to fill a tank with the stream from the ten stamps after the tank is full the stream is still continued in the tank for from one to four hours longer and notwithstanding the stirrer is always in motion the mass is perfectly quiet on top and all the slimes and sands settle while the solution overflows clear and is run to the gold tanks to be precipitated when the tank has the proper charge in it the stream from the battery is turned to another tank and the leaching operation commenced by entering in solution at the bottom of the tank drawing same from a storage tank set just above the top of the ore tanks which percolates up through the mass and not only makes a perfect dissolution of the values but at the same time washes them out over the top into the gold tank and recovers them by the use of this process a large quantity of solution can be brought in contact with the ore as from ten to fifteen gallons per minute i is s run through each tank and by so doing a much weaker solution can be the echo mill at mojave javO cal used and still bring the necessary amount of cyanide of potassium in contact with the ore to effect the maximum extraction by the use of the weak solution a considerable saving is effected in the consumption of cyanide it takes about twenty four hours to thoroughly leach and wash out a charge of which about twelve hours is consumed in leaching or running in solution and twelve hours with water to displace the cyanide solution the echo ore produces about 50 per cent slime of the very lightest character and were it not for the fact that it is so light a very much larger quantity could be treated at a charge it takes six tanks to treat the product of the ten stamps while in the case of the april fool four tanks would be sufficient for the reason that the slime of this ore is very much heavier or of a greater specific gravity the tanks hold bold about eight tons of E echo cho ore while they hold about fifteen of the april pool fool lime is used in the solution to coagulate the slime and to feed this evenly a small agitating tank about three feet in diameter is used in wh ch the slacked lime is put and by allowing a small stream of solution to run in on one side the overflowing stream at the other side carries a continuous stream of milk of lime to the launder where it mixes with the pulp after the latter has left the plates or tables the tailings are caught in a dam and the surplus water pumped back again by means of a small gasoline pump but at the april fool this was done by operating a post or plunger pump set down below the dump by means of a small wire cable which could be started or stopped at the mill without going down to the pump this latter is by far the more satisfactory way at both mojave and de lamar the climate is very hot and dry and there was considerable loss of water by evaporation yet at the latter place it was less than one part of water to one part of ore and at the former it was a little more the solution used at both places averaged about 05 per cent strong and no trouble was expert experienced encee in effecting a perfect precipitation by passing it through the zinc boxes at the rate of 13 tons of solution per cubic foot of zinc in twenty four hours the boxes are made of wood each containing ten compartments three feet wide or width of box one foot long or lengthwise with box and eighteen inches deep and so constructed that the flow of solution is downward in each compartment instead of upward as is most generally the case experience peri ence has proven to the writer that a better contact is obtained with the zinc when the solution is passing downward instead of upward the echo ore averages from 10 to 30 per ton of which the echo com company pany has immense bodies blocked out and after the agitation treatment the tailings are mere traces the water escaping with the tailings rarely assays essays more than a few cents per ton which shows that not only dissolution of the gold is practically perfect but that the recovery is so as well one reason for this rapid and complete extraction is the fact that the solution is used warm being heated at no cost by exhaust steam the heaters are coils of four inch pipe placed in the storage tanks and they not only heat the solution but condense the steam and return condensed water to the boilers warm and free from lime etc A warm solution greatly assists the action of the solution in dissolving silver and helps mechanically in facilitating the settling etc at the april fool the extractions by as says averaged 93 per cent of the gold and 70 per cent of the silver while by the old method of percolation for a period of eighteen months run of mill previous to the process being changed the average extrac eions were only 70 per cent of the gold and 33 per cent of the silver in addition to the extractions as indicated by the daily samples ts the actual recovery of bullion by the agitation process ran from 12 per cent to 15 per cent in excess of what the assays essays called for the reverse was true of percolation the ore carried about 10 gold old and four ounces silver the former percolation practice was to crush with water and settle in mason work pits and then mix up the sands and slimes by hand and shovel and tram to the leaching tanks owing to the impossibility of perfectly mixing the wet slime with the sands the percolation and consequently the extraction was very poor indeed great prejudice has existed in the minds of most mill men against the use of cyanide solution in the battery claiming it to be injurious to the plates but this was tried at both the echo and april fool plants and found to be perfectly successful while the recovery of gold by the plates was of course materially reduced owing to the fact that the solution dissolved it in the battery yet the final tailings showed conclusively that what the plates did not catch the solution did naturally some fine gold would be dissolved by the solution which would otherwise be caught by the plates but further than this the work at both mills proved the use of cyanide in the battery to be successful and that no material detrimental effect was noticed in the plates that would prevent them from catching free gold the recovery on the plates at the echo when using solution was about 30 per cent and at the april fool about 20 per cent without cyanide about 60 per cent of the gold would be caught on the plates at the former but by the use of the solution in the battery it saves the time and losses incidental ci to the extraction of the water from the slime and the substitution of the solution which in other words means dollars and cents also by the use of th the solution it keeps the plates in good condition when working base weathered ores while using water in the battery a few hundred tons of base weathered ore was treated at the april fool plant and owing to the afie lead and other bases the quick got so badly sickened that the plates would have to be cleaned off every hour or less but when the solution was used to crush with instead of the water this was instantly overcome and the plates were kept in the very best of condition the advantages of this process are in its ability to cheaply and perfectly leach slimes and climey ores at a small cost the costs of this process are no more than by percolation or settlement and decantation and where fuel is not too expensive or where the conditions are normal the costs are considerably less there is an extra cost tor for fuel but as the agitation tanks do not consume more than about two horse power or less this cost is more more than equalled equal led by the great saving in labor the consumption of cyanide is less than other methods for the treatment of slimes it competes more especially with the settlement and decantation system and will do better and cheaper work at a less cost for construction of plant it obviates the necessity for any separation of sands and slimes as the former can be worked to very good advantage along with the latter at a very small cost per ton thereby simplify ing the operation to the extent of having but one part or process to the mill it is also very frequently the case that a very high extraction of values especially silver could be obtained if the ore was ground very fine but by so doing the difficulties ordinarily would be so great that it would not pay by this process however it would be rather more of an advantage than otherwise |