MR ULRICH’S REPORT.

Cromwell Argus, Volume VI, Issue 289, 26 May 1875, Page 6

MR ULRICH’S REPORT.

We continue our extracts from above. Of “ Group 3,” which embraces the Garrick Range reefs, Mr Ulrich says : The generality of these reefs present in several respects quite different characters from the reefs of the other groups. They are peculiar clayey ferruginous “ mullock reefs” or rather “quartz-mullock reefs,” so soft that they can mostly bo worked by pick without the aid of homing or blasting ; and the quartz, which apparently forms no large per-centage of their mass, occurs only in the shape of coarse sand, and small angular and slightly rounded pieces—such reaching or surpassing the size of a fist being rather rare. Some of the reefs show much irregularity in their course, for they expand and contract, twist and curve in strike and dip in quite a peculiar manner, and are—what is the case also with roost of the others—frequently faulted by slides and cross-courses, so that it requires very great attention and perseverance on the part of t.he mining managers not to lose them. Unfavorable as these features no doubt appear, touching straiglrorward and uninterrupted working of the reefs in future, I feel no apprehension of the latter giving out suddenly, or qt a limited depth, for they are in every respect true lodes, crossing the country both in strike and dip. and showing most frequently the hanging wall, less frequently the foot wall, and in some instances both walls well defined and separated from their mass by clayey casings, mostly polished and striated, representing the so-called. “ Slicken-sides,” which afford unmistakable proof of movements of the walls of the reefs. The gold, both in the quartz and mullock, is very fine, and, owing to the soft and ferruginous nature of the stuff, specks can but very rarely be seen during working. On account of its softness the quartz mullock is easily crushed, but the saving of the fine gold requires great attention ; and, as the supply of water, which the proper treatment of this kind of stuff requires, is rather above the average, hut has at the existing machines been frequently much below it, and their saving appliances are not the most suitable ones besides, I am sure a great deal of the gold has been lost in the tailings. There is at the level of even the lowest workings not much pyrites observable in the reefs, still the ferruginous character of the mullock, as being no doubt a result of its decomposition, points to its former presence in larger quantities, and it may with certainty be expected to increase in abundance in depth. As regards the expense of working the reefs, the soft nature of both the mullock and country renders it small in one respect, viz.: —that of exploitation proper ; in another, however, viz.:—that of supporting the workings, rather large, on account of the high price of timber, ami the expense in this respect increases of course, in order to avoid accidents and collapse, the flatter the dip of the reefs. Fortunately there are on this field experienced managers and miners, well able to cope with this difficulty in the most economic and practical manner, CHANCES for PROSPECTING FOR NEW AURIFEROUS REEFS. ' As regards the chances of the occurrence of other auriferous reefs in the districts under notice, I consider them to be very goo 1. At Bendigo, the Garrick flange, and Skipper’s Greek, where the tracing of auriferous gullies and quartz specimens led, I was told, to the discovery of most of the principal reefs worked, though some showed by no means plain outcrops at the surface, partly by reason of their innllocky character, partly on account of being covered bv detritus or being disturbed. And these features are the most serious obstacles the intelligent prospector has to contend with in these districts, for that the latter are promising tiel Is for further discoveries of quartz reefs is plainly indicated by numerous auriferous alluvial gullies and creeks, and the occurrence of quartz specimens eutside‘the drainage range of the known lines of reefs. The recent discovery bv tracing specimens of a new reef in the Bendigo district presents a case in point. The same reasoning, based upon similar data, applies more or less to all the other reefing districts (Arrow, Rough Ridge, etc). Concluding with a general comparison between this Province and Victoria as to the facilities and chances of prospecting, I must say that this work—looking at it in a strictly mining point of view only—is here much more difficult than in Victoria. ; for, whilst there reefs consist mostly of massive white quartz, and are plainly exposed on the surface, they arc here more frequently of a mnllocky character, and more or less covered over by detrital matter. And there is besides one striking difference between the two countries, namely, that whilst in Victoria reefs abound ad through the goldfie ds, but as the saying goes, ninety-nine in a hundred prove barren, here they are comparatively very scarce, but with this redeeming feature, that nearly everyone hitherto found has proved to be auriferous, and theref >re, we may fairly assign the same chance to any new ones discovered in future. CRUSHING MACHINERY AND GOLD-SAVING APPLIANCES. The number of crushing machines erected and in’eourse of erection at the different goldfields I visited, amounts to twenty-one. * * * * Touching the height of drop and speed of the i stamps, the former should he less than seven inches, and might be advantageously increased to nine inches, especially if the stamps are light; whilst, touching the speed, it is generally considered best at the rate of 75 to 80 blows per minute. Regarding the iron coffers, they seemed to me rather, if not too shalloiv for both economic and effective working. They allowed hardly one inch of loose quartz to he put beneath the false bed plates, and it would, therefore, require the greatest care in the placin; of these plates, the feeding. &c., to prevent the plates 1 from working unevenly into the shallow gravel bed. In fact, 1 think it can hardly !• avoided that they (the plates) come frequently in contact i with the iron bottom, the result of which, of course, i , as the sound of the blow already imii- . cates, ineffective working and gieat wear and I tear—sometimes even an unexpected breaking of •the coffers. On this account I think it would certainly be advisable to have the latter, say, about two inches deeper, so as to allow a gravel s bed of three inches beneath the false bottoms, i Considering that the office of these latter is not i only the saving of the coffers from wear and ■ tear, but mainly to prevent the gold from being smashed too fine or “.beaten dead,” aa it is

called, they should ho the same aim as the stamp-h'iads, in order to leavo Buffieienfc spare around fioin for liberated gold particles to got into the gravel out of tho reach of the stampers. The provision of self-feeding hoppers—a great desideratum for saving labor—has been negleoted at a great number of the machines, and would deserve early attention. Many practical quartz crushers considers, and no doubt rightly, that hand feeding, if properly executed, is more effec* tive; still it is extremely doubtful whether, especially in the caße of small machines, the value of the increase in the quantity of stuff crushed is equal to that of a man's labour ; in my opinion, this labour is far more profitably applied to attending upon the gold-saving appliances. With only one or two exceptions, I found the great defect of the coff-.-rs having only front discharge ; for it must stand to reason that, as it is, or ought to be, the aim to get the finely crushed material quickly out of the boxes, large escapes both in front and at the back are most effective. As regards the gold-saving appliances in use, they consist, with the exception of two machines, which have deep drop-ripples attached, of amalgamated copperplate tables, in some instances with improvements in the arrangement of the ripples, and all, except the cement crushing machines, have various lengths of blanket-stakes succeeding. I would recommend the exchange of the present appliances and system for, or respectively their modification according to those for years successfully in use at the Port Phillip Company's works, Chines—an establishment which in Victoria occupies the foremost place in satisfactory gold extraction, mainly because the practice there introduced of daily taking and assaying samples of the tailings serves not only for controlling and guiding the working of the appliances adopted, but in the case of any new invention in gold saving being tried, it affords also the best proof of the merits or otherwise of the latter. The system of appliances used at Chines simply consists—starting from the battery—of three connected quicksilver troughs—the first with a 10-inch drop, the second with a 9-inch, and the third, or lowest, with an 8-inch dropthrough which the material passes in succession, to run next over 24 to 27 feet of blankets r ikes, laid at a pitch of only one foot in 16. and ultimately to pass from the blankets through another quicksilver trough before it reaches the waste channel. This last trough is only cleared, however, at intervals, whilst the upper troughs are cleared every week. In order to keep any coarse stuff from entering these latter, and also for even distribution of the material, a perforated plate is fixed right in front of the battery, through which both hack and front discharge pass on to an apron which leads it (the material) into the first trough. An important part of each trough is the splash-board, which, reaching down to within about one and a half inches of the bottom (of the trough), near to the surface of the quicksilver compels the material, in its drop, to pass more or less through the latter before rising over the lip of the trough. All the troughs are supplied with tap-holes on one side, by means of which the quicksilver and amalgam can be drawn off when required. As to the blanket-strakes, their small inclination requires the supply of water to be up to eight gallons per stamp-head per minute, according to the nature of the stuff, in order to keep them free from sandy settlement. The rate at which the blankets are washed at Clunes is generally the upper row every hour, the second row every two hours, and of the reraainiug length of the strakes. the blankets of the upper half everv six, those of the lower half every twelve hours. Considering the nature of the stuff of the Otago reefs. I think, however, that .partly because the the more or less slimy stuff from mullock reefs renders the surface of the blankets.quickly inactive, partly on account of the great amount of pyrites contained in Ihe quartz, a more frequent changing than the ahoVe is advisable. TouchiiTi the treatment of the blanket-sand, the method in use at most of the machines, viz., by rei r olvi:)g barrel and shaking table, gives, if properly carried out, the most satisfactory reand deserves, therefore general adoption. Having been informed that at several of the machines the practice is followed of putting round stones or pieces of iron into the barrel, in order to grind the sand finer and aid the amalgamation of the gold, 1 have to remark that I consider this proceeding likely to prove more harmful than advantageous, on account of the large qnantitv of pvrit.es generally present in the sand, which through the gr'nding is likely to sicken or flour the mercury and amalgam, and this invariably is followed by a loss of mercury and gold afterwards.