HOW TO IMPROVE DIVIDENDS FROM MINES.

Auckland Star, Volume III, Issue 761, 24 June 1872, Page 2

HOW TO IMPROVE DIVIDENDS FROM MINES.

To the Editor of the Evening: Stae. Sm —I feel sure, from the interest you always show in what is likely to benefit our mines and batteries, that you wiU call the attention of your subscribers to the well-known fact, long acknowledged by all practical men, that to crush quartz effectively-for goldsaving purposes you must crush it fine—the finer the better ; in proof of which it has been repeatedly found in Victoria that poor stuff crushed with large-holed, or what are caUed coarse gratings, has not paid expenses ; while the same stuff crushed and passed through fine gratings—though it cost a higher price .> for crashing—has left a margin of profit. Hence has arisen the general desire to crush as fine as possible, but, like all other things, this has its limits, and those once passed, the obstacles to it increase in compound ratio so that every step in advance both reduces quantity and increases cost. For example, 50 tons of quartz may be passed through a grating of GO holes to the inch in a given time, but with a grating of 120 holes to the inch it will take double, and if at all mu'locky, often more than double the time ; but with a grating punched so as to have 180 holes to the inch, fully four times as long wiU be required to put it through as would have been the case if one of 60 holes had been used ; and when the quartz is half mullock, as it often is on this goldfield, it becomes most difficult, and sometimes quite impossible to make it pass through fine gratings at aIL (Ordinarygauges and perforations are, of course, only referred to in the foregoing examples.) It is therefore evident that any machine - which wiU enable 10 heads of stamps to use gratings of only GO holes to the inch, and yet "will crush as fine, and get through as much work, and do that work in the same time as a battery of 20 heads using gratings of 120 to the inch, will in reality make the two batteries equal in every respect; but if, m addition to doing this, it can be shown and proved that by means of this machine a battery of 10 heads, using only 60-hole gratings, wiU crush any kind of quartz, whether muUocky or not, much finer than if it had gone through gratings having 200 to 300 holes to the inch, then it stands to reason that 10 heads of stamps acting in connection with" this machine will be found far more effective for crashing quartz for gold- " saving purposes, by crushing so much finer, than three or four times that number of stamps without it. I I must now inform you that the machine referred to is "Stovin's patent triple-action grinder and amalgamator " and, as the patentee, I claim for it.that if _j placed at the foot of the battery boxes, with a shoot from two boxes of five heads each, it will do away with both plate-tables and blanketing," and in that case the battery house can be kept under lock and key and cleaned up once in 24 hours; but, if preferred, it can be placed at the foot of the plate-tables, as it entirely does away with blankets or skins, and in . addition to" the foregoing it combines the following most important advantages, which together would be found an immense economy over the present system Ist A great saving in the cost and erection of large plant, as a small battery, with a little more power in - the engine, would do as much or more work^han a , _ large one, and for gold-saving purposes do it in a-far ~ superior mariner, by reducing the quartz operated ; . upon infinitely finer than any fcattery could do. 2nd A great reduction in weekly wages, there being only half, or less than half, the number of stamps to feed though more than double the amount of work would be obtained from them, plate-tables made op--tional blanket washings entirely done away with, and w one berdan to 10 stamps only required. y * 3rd A most important saving in silver ; as it is no longer necessary to beat it up in the battery boxes, it will therefore not be floured and rarely sickened, vi consequence of the three processes of crushing, grinding and amalgamating,, though carried on at the • same time, being kept entirely separate. _• # ..;... 4th Every battery to which this machine is attacnea will liave the great" advantage of working up. every <> particle of its own tailings, and effectually saving the .-- gold from them, as they will be ground up to the finest, powder, and amalgamated simultaneously With the . general'crushing and amalgamation. ' , yi sth In amalgamation, time is an essential element of success; the strong stream of water usually rushed over the plate-tables, and the too great incline customary in those tables, carries the gold away without allowing it sufficient time to come in contact with the prepared plates. Added to this, the plates of tens become coated with slime from foul water, and.-the y silver on them sickened from a variety of causes, so that in reality at least half the gold is lost. . .-' In Colorado and Nevada skins alone are chiefly used, real sealskin tanned with the hair on being the best, but failing that, calfskin, or the material known as sealskin cloth; these laid over the plate-tables, with the hair pointing vpwards, have been recently proved at the Moanatairi battery to save 20 per cent, more sold than the copper-plates ; but a far greater saving, calculated by experiment to amount to 80 per cent,, has been proved to result from running the crushed ciuartz as it comes from the stampers direct into the Blinding-pan, and thence into the amalgamator, where time is allowed for perfect amalgamation to take place, and fpr, which this machine is especially 11 Houing these particulars may meet the-eye and gain the support of some one of sufficient enterprise to practically test its merits, for assuredly if the machine is found to act as I am convinced it will, the P™r, of this invention will gain liu■reward and confer a lasting benefit on the goldfields of New .gjg^fes; 1 [We*eaW that Messrs Masefield and Co. (of whom ,; all particulars can be obtained) are appomted manu-. : | facturers for the patent grinders and amalgamators ■ -or Auckland.—Ed. B. S.} .".'•'"