Show I 1 DIN 0 BEFORE OR OF TER by floyd written weed teed for the E MI ma mining kimberley R review utah abe HE question of amalgamation preceded in ins or following cyaniding cyan iding cannot be discussed pro and con on the general merits of the two methods but the character of the ore will determine in nearly every case the relation between the two not considering local conditions which may be a most important factor in choosing the exact procedure careful preliminary experimenting will show in the majority of cases which is preferable of course as new zealand practice shows the actual running on a large scale may develop in any method such disadvantages and difficult difficulties ios as may cause a change to another and this only emphasizes the fact that not only determinative experiments should be made but also those corroborative in their nature to illustrate it is not sufficient to amalgamate and determine the extraction by that method following this by cyaniding cyan iding the tails but the ch character arader of the slimes their rate of settling amount of time required to effect this the proportion to the entire product should be studied with the greatest care as in the case of manganese slime the settling or filtering on a small scale is accomplished with no apparent difficulty the extraction is usual high but on a large scale the area of necessary to effect this would be found to be enormous unless filter presses were used slimes from the oxides of iron present the same difficulties but as the tendency in their case is to contain lesser values than manganese and clay slimes the question then arises if it is not more economical to combine their treatment with the balance of the ore 11 A possible procedure in the case of dry crushing rather than separate them by previous amalgamation and then allow them to run to waste or be treated by a separate slimes process often cumbersome and expensive even in the case base of exceptionally high extraction by amalgamation this question of handling the slimes may show a loss or additional expense which by handling in conjunction with the balance of the ore may be avoided values recoverable by amalgamation before cyaniding cyan iding are recoverable by amalgamation after cyaniding cyan iding while the converse is not true values as in the case of rusty gold are recoverable erable by amalgamation following cyaniding cyan iding while no not t by the reverse the simplicity of operations incident to the recovery of values by amalgamation will always be a tempting factor in the selection of a process but when the handling of separated sands and slimes is considered the method may be more complicated than reversing the process amalgamation following cyaniding cyan iding is a simple op operation aeration era tion the presence of too much free cyanide with its tendency to harden the plates can be avoided by more careful washing while the presence of a small amount with its brightening effect on the plates is an advantage lime too in neutralizing the acidity previous to chanid ing is beneficial so we have plates kept in good order with the minimum of attention two methods may be used in handling the tailings over the plates in case it is found the first contains no amalgamate value hy classification in pointed boxes with the sands run over the plates may be used the plates are arranged in ift tandem head to head one box distributing to two plates if the entire product is to be passed over the plates it may be sluiced direct over a large area of tables or run into intermediate rectangular boxes or tanks these being provided with a traveling carriage and hose attachment giving a constant uni uniform form feed to the plates during the intervals between sluicing one objection often used to cyaniding cyan iding before removing the coarse free gold is that as long as any free cyanide remains in the tanks there is a constant though slight solution of the gold therefore it is difficult to show a solution free from values when adank a tank is ready for sluicing this may be in some cases worth considering but if sufficient w wash a sh is used the actual amount of wash containing conta containing inin a cyanide left in the treated ore will bear such a small proportion to the entire tonnage that it may be neglected wet cru crushing shino with cyanide solution has found many advocates and is practiced successfully cess fully in many places this necessitates amalgamation following the leaching aside from the great bulk of solution to be handled as compared with dry crushing the advantages are obvious perfect aeration and agitation in contact with the solution the arguments against this process are the same as apply to dry crushing ore containing coarse gold and also wet crushing certain charac of slimy ore weighing carefully the characteristics of an ore is the only guide in choosing |