PROFESSOR ULRICH'S REPORT.

New Zealand Tablet, Volume XIII, Issue 35, 25 December 1885, Page 9

PROFESSOR ULRICH'S REPORT.

The following is the report of Professor Ulrich to the Minister of Mines on Green's reef at Ophir :— " Fniversity, Dunedin, " November 23, 1885. " Sir,— l have the honour to inform you that under the guidance of Mr. Green, Mr. Pitches, Mr. Bannerman (agent for Colonial Bank) and other gentlemen interested in the Ophir district, and who gave me every information desired, I inspected Mr. Green'B celebrated gold discovery as well as other occurrences bearing some resemblance tort, and also the drift deposit at Ophir and Blacks No. 2 and No. 3 The result of my inspections are as follow : "MB. OREEH'B ACBirBROUS DEPOSIT. " This is at present exposed and prospected for a diptance of eight to nine chains, and in one place for a width of near 30 ft running at a strike of East lOdeg., N.W. lOdeg. between two gullies across an intervening ridge, which is about 60ft. in height. Near the top of this ridge, on the eastern side, are several old shafts, sunk by former prospectors, and it is here where Mr. Green first found the richly auriferous quartz specimens (the auriferous character of the ■tuff which is presently to be described), and has so far carried on most work. The stuff composing the deposit consists of a thinly laminated, decomposed, soft, and friable metamorphic schist, probably originally chloritic mica schist, showing a nearly horizontal bedding, and being more or less abundantly traversed in all directions, from horizontal to vertical, by broken quarts veins ranging from a thin thread up to an inch in size, and soft, wkite mineral occurring frequently in irregular small patches and veinlets proved on examination to be rihcate of magnesia. The colour of the decomposed schist when freshly broken is greyish blue, but fades quickly on exposure to the atmosphere to a bluish white, interspersed with brown ferruginous spots. According to Mr. Green's trial washings, and some executed in my presence tbe gold is distributed through the stuff in spongy crystalline particles from the size of a bean down to a state so fine and light as to be hardly recognisable Jby the naked eye and scarcely retainable in the tin dish. Besides this it occurs in the quarti-veins, especially those with a steep or vertical dip, some of which have furnished specimens of great richness, consisting in cases of more gold than quarts, and a few which Mr. Green showed me would if tbe quartz were broken out. yield small nuggets from several pennyweights up to perhaps nearly an ounce in weight. Owing to the irregular distribution of these auriferous quirts veins, it is impossible for an estimate to be made of the gold contents of the stuff in the average ; but so ranch can with certainty be foretold, that, should the ground on further exploration in a strike and depth prove as rich throughout as at the place about the aid shafts, Mr. ■ Green will soon become a very rich man. " fiegarding the geological character of the deposit, and what it represents in a mining point of view, I was enabled to make the following observations : An open cutting between the old shafts •Hows that the soft stuff is sharply cut off on the south Bide by a hard t[uarti vein a few inches in thickness dipping N. lOdeg. W. rather unevenly at an angle varying 60deg. to 70deg. Beyond this quartz vein, which is called the * Captain Reef," and for the prospecting of wnich old shafts have been sunk, follows a thinly laminated micaceeus quarri schist, showing a nearly horizontal bedding. The quartz vein has mostly been removed out of the quartz schist but at one place a patch is left showing * finely polished surface with deep stnations normal to the line of strike— a so-called slickenside, whilst the ends of the laminations of the soft stuff are slightly turned upward on tbe quartz veins. Whether towards the north a similar wall exists has not bern proved as yet, and nothing can be seen on the smooth surface for a distance of about two chains, where Mr. Green has prospected with fair results of fine gold. From the gully upwards to near the top of the ridge is a second vein of soft decomposed rock striking parallel to the first, but showing a lighter colour and more abundant and larger ferruginous patches. Adjoining this further northwards followe a chloritic mica schist, which, though soft in the gully through the action of the water and richly impregnated with pyrites, becomes soon hard up the ridge, exhibiting there massive rocky outcrop*. From these features, considered in connection with others, clear evidence is afforded by the second side and the adjoining qnar-t schist that in the line of the Captain Beef a fault has taken place wnh the result of a downthrow of the auriferous rock from probably a very high level, whilst in case of a second wall being found to the northward beyond the Recond run of soft aurirerous rocks, for w),ich there is some probability, the whole of the intervening mass would constitute a huge mullock reef, such as exists ™,?X I"' "*}*.? Sk LPP era Cre <* a °d °»any places in Victoria. The alteration of the rock and its impregnation with gold within the two lines of nssares, or, at any rate, of the faulting fissure, rnnnin? alone |jhe Captam r<*f, in my opinion is mainly due to tbe meteoric waters *mcc circulating in these aWes-a hypothesis for which the fact apeaks somewhat m favour of the richest specimens and the best prospects of loose gold having been obtained by Mr. Green close along the Captain reef, along which itself has so far not proved eoldnf^fi 'i!fs fr 2 m vT lar in Victoria, a great part of the fine gold is doubtless derived from decomposed auriferous pyrites, an ore which may likely occur as a rich impregnation of the rock in the depth below the permanent water-level. There can hardly be a doubt that the fault, and with it the deposit through strike, is greater than at present opened. Several chains to the westward, on the western side of another Gully, Mr. Green obtained from a greenish re tten rock fair prosjects of fi D e gold of a similar character as occurring on the soft rock of his workings. Prospecting further westward would, however, be connected with difficulties as the line of strike of the fault runs across a drift terrace into tbe flat and extends through the township of Ophir. Towards the east the coanceof the ex'eo B ion of the deposit, at least of the same width. ■earns unfavourable, as the ridges in that direction showing the line '

of strike of the fault are massive outcrops of hard metamorphic rode rather close together. " Regarding the extraction of the gold from the mullock, the softnest and friability of the latter permits of its quick conversion into fine mud by the action of the water, and therefore the use of a puddling machine and a plentiful supply of water, and the crashing of the quarts portion remaining in the mill, would in my opinion, he the most advisable process to adopt. "Since Mr. Green's discovery several places showing similar decomposed rock have been tried on the ridges in different parts of the district, but apparently without success in finding pajable gold. "A place called M'Leod's Working deserves, I think, some further explanation, as the run of rotten rock seems to strike nearly in the same direction as that of Green's, and prospects of fine hackly goli are said to be obtainable from it by the tin-dish trials. Considering the great scarcity of quarts reefs in the district, in conjunction with tbe fact that there are a number of surface workings and dry alluvial gullies high above the boundary line in the mountains, which have yielded payable gold from gravel with very poor appliances and sm»U capital, it an efficient water supply were brought down from the Upper Manuberika (which I was told would be the most advisable course) on to the range ftbove Ophir, it would not only permit the hydraulic sluicing of all the township bat would lead no doubt also to the discovery of other high drift deposit* of equal richness in quartz. It is highly probable that such gold was derived from mullock deposits similar to that at Green's. The district, therefore, certainly deserves more extending and systematic proepectinf. " THE DBIFT DEPOSITS AT OPHI* AND BLACKS, HOB. 2 AND 3. " fiegarding these, I cordially agree with Mr. Pyke that they are uojustlv neglected, and oiler excellent chances of rich "returns to enterprise. Lower down the valley, towards Alexandra, the workings at Blacks Nos. 1 and 2, now nearly abandoned, indicate, as Mr. Pyke sayß, tbe existence of a genuine deep Ihml, but examination of the ground and information about the depths towards the broad Ida Valley, in which no doubt a deep main lead lies hidden, are required. Tbe two branch leads start at Blacks No. 3, very shallo v from a saddle between the main range and an isolated outcrop of metamorphic rock, and run for three-quarters of a ,mile down the valley along tbe foot of the range towards Blacks No. 2, reaching gradually a depth of over 100 ft. The other runs up the valley, curving towards the latter, bat reaches already to withio a snort distance of tbe last shaft worked from a depth of close upoa 200 ft. This shatt, according to information kindly given me by he lion. Captain Fraser,who was interested in the claim, was abandoned on account of a body of water breaking into it, and from the very limited workings nearly £2000 worth of gold was obtained. About the result of workings on other leads, Mr. Pitches, who knows tbe field im innately since its opening, gave me a most favourable account. Payable and even ticb gold was found in most of the claims, as much at 40oc. a day In one case, and the lead was not lost. Only the great expense of timbering, occasional trouble with breaking in of drift, and principally the rush to the West Coast, led to the gradual abandonment of the field. Not. doubting tbe correctness of all tbe information given I can only say that if such a promising pUce were in Victoria it would be rushed directly. It only requires several parties of skilled miners with sufficient capital and one or two well manage! companies to n commence working, and 1 have no doubt that this deep-lead field will again become prosperous and attract a large population, the more so as there is every probability of similar branch leads and surface dntt* as those worked existing and being optntd up along the as vet unprospected foot of the ridge higher up tbe valley.— l have, etc., "Geo.H.F. Dlbich."