THE LATEST IDEA IN QUARTZ CRUSHING.

Grey River Argus, Volume VIII, Issue 537, 26 June 1869, Page 4

THE LATEST IDEA IN QUARTZ CRUSHING.

(From the Adelaide Evening Journal.) The philosopher's stone has been discovered at last, and the " precious metals" will soon be ao abundant as to belie their name. The discovery has been made by a Yankee, of course. Dr Hogan, of Albany, New York, had he lived nine or ten centuries ago would have been an alchemist of world- wide renown. His inventions would have made Roger Bicon and Schwartz appear mere schoolboys in comparison. They would have exhausted the wonder, if they did not shock the credulity, of the age at firat hearing. The doctors would have proved by Aristotelian logic that Dr Hagan was not only an emissary of Satan, but Satan himself . His extraction of gold from base ore would have made them cross themselves before his enchanted crucible, but his using water for fuel would have seemed to them a blasphemous perversion of the course of nature. Yet these combined feats are what Dr Hagan has in this nineteenth century undertaken to accomplish by means of his patent furnace. He has had it introduced among the gold mining companies of California, and it has undergone a very successful test at one of the Cisco mines. Though in this Colony we have not as yet had much experience in the reduction of auriferous or argentiferous quartz, we know enough of the difficulties which have hitherto attended the process to be able to appreciate even a slight amelioration of them. The richest gold and silver mines afford little satisfaction in working compared with what they might do if more control could be obtained over the raw material. Notwithstanding the exercise of many years' ingenuity and the expenditure of vast sums of money in the endeavor to control it, that control is still very imperfect. But a small proportion of the precious metal can be extracted from the ore, and to obtain that very expensive and complicated machinery must be used. Moreover, the latter is always undergoing changes and modifications. The finest crushing plant of to-day may be old-fashioned and require renewal a few months hence. Like the English Admiralty in its competition between the ironclads and Armstrong guns, the quartz crusher is always running a wearisome race with himself and gaining very little by it. The so-called improvements of the Californian and Ballarat regimes have probably done little more than pay expenses. At all events quartz crushing is admitted to be still in a very rude state, and the art of extracting the precious metals falls far short of the scientific ideal. There is still a waste of labor and a waste of material tending to depress this, which ought to be the most remunerative industry under the sun, to a very slightly higher level than the ordinary forms of occupation. But Dr Hagan undertakes to remove that anomally once for all. Dr Hagan's furnace will leave nothing for mining engineers and inventors to improve upon. It will bring the most rebellious ores into absolute subjection. It will simplify machinery, and economise labor to the lowest point. And, as a crowning triumph, it will raise the produce of gold and silver to the natural standard. The most inferior quartz will become payable when it is brought into contact with the Hagan furnace. All the secondary mines which have lately been abandoned may be resumed with the help of a small outlay on the Hagan furnace. While fortunes are being saved at the lower end of the furnace in the cheap fuel used, other fortunes will be gained at the upper end by the expulsion of all the base metals which retard amalgamation. The increased facility of crushing will of itself repay the expenses of roasting in the Hagan furnace, it having been proved at Cisco that the stamps can crush twice as much roasted as common ore within a given time. But it ib not till amalgamation begins that the full value of the Hagan invention can be realised. The purification of the ore then enables the quicksilver to combine readily with the precious metal, and an easilyretorted amalgam is the result. The Californian papers are very jubilant on this latter point. The productiveness of the Californian mines has all along been seriously impaired by the excess of base metals in the quartz, and the difficulty of separating them so as to free the gold for amalgamation with the quicksilver. A process of chlorinisation has been tried in some districts, and, though it is acknowledged to have increased the yield, it is expensive, anl has various drawbacks which would retard its general adoption. For one thing the quartz must be crushed before chlorinisation becomes available ; and this not only leaves the principal cause of expense untouched, but it is injurious to the free gold. There is, further, a heavy loss of sulphurets in concentration ; and, finally, what is saved of the sulphurets has to be treated by a costly process of roasting. Chlorinisation and the other improvements yet introduced have been indirectly beneficial in showing that any separation of the base metals, to be really economical, must take plate before the ore is worked at all. The question put by the gold miners, and answered by Dr Hagan, is— "How can ore be prepared for crushing so that the quicksilver will have full and immediate effect upon it whe:«. crushed ?" The Hagan furnace is not only remarkable in what it undertakes, but in the

means it uses to attain its object. It has a novel fuel —water —which it burns in an equally novel fashion. The test furnace on the Enterprise Mine at Cisco consists of an ore chamber, four feet in diameter and eighteen feet high. Underneath this is the fire-chamber, of corresponding diameter and four feet deep. A steam boiler stands close by, and a pipe from it passes over the fire in bends, terminating under the fire. The steam in its, passage through these hoops becomes superheated and dissolved into its component gasesoxygen and hydrogen. The latter escapes at the bottom through the fire to the top of the ore-chamber. By this simple method of diffusing heat —'the heating surface being extended ten times beyond that of ordinary fires —a dozen tons of ore can be roasted as fast and on as small a consumption of fuel as one ton. The contents of the ore-chamber at Cisco average eighteen tons and the period of roasting three days. But it is fed without stoppage, six or seven tons being withdrawn every day from the bottom, and an equal quantity of fresh ore thrown in at the top. The decomposed gases carry off all the arsenic, antimony, and sulphur, in the quartz, and facilitate the subsequent processes of reduction. The roasted ore can be crushed twice as fast as common ore, and the amalgamation of the quicksilver with the free gold is both more rapid and more thorough. The above experiment had been a very short time in operation when the account was written from which the foregoing has been condensed.