REPORT ON THE GOLD FIELDS OF OTAGO.

Otago Witness, Issue 1241, 11 September 1875, Page 15

REPORT ON THE GOLD FIELDS OF OTAGO.

By G. H. F. UwtioH, Esq., F.G.S.

THE ItXTCKNOW BEEF AND CO. The strike of this reef is nearly E. and W., its dip close upon vertical, and the walla are well defined. It has been opened along the surface for about 300 feet in length, the main workings lying on top of a spur, which it crosses at nearly right angles. As these workings were inaccessible, Mr Charles Colclough, the original discoverer of the reef and present legal manager offjthe Company, kindly afforded me information about them, and gave me other particulars concerning the reef. The latter has been worked out to depths ranging from a few feet to 60 feet, and yielded from 8 dwt to over 3 oz of gold per ton. In the main shaft the reef, which, proved about 1 foot thick, was followed vertically down to a depth of about 100 feet, but there a body of stone made its appearance, rich in gold and arsenical pyrites, and showing a thickness of 3 feet, i.e., one foot of quartz on either wall, and one foot of mullock in the centre, and which was found to dip flat southward. The shaft was, therefore, turned on the underlay of this body, which was supposed to represent the main reef, and for a length of 14 feet followed it down to a depth, of about 146 feet, where water was met with. A crushing from this underlay portion greatly diaappointed, however, all expectations ; for instead of several ounces, it paid only from 8 to 11 dwt of gold per ton. As it was thought that the water would give too much trouble in further sinking, and also in order to provide an easy road for the stuff to the machinery standing in the gully at the foot of the spur, an adit was at onoe projeoted and started from near the machine without considering that the length it would have to be driven through, hard, nearly horizontal, mica schist to strike the reef, and consequeutly its large expense was greatly disproportionate to the small height of backs-^estimated at hardly 40 feet — to be rendered available by it ; irrespective of that— -in which most opinions agree — closer examination would have shown that the water in the shaft was mostly due to surface percolation, and might have been easily beaten by a horse whim. At the time of my visit, this adit, which makes two strong angles in direction, had progressed to a point which Mr Besanko, the mining manager, considered from rough measurements — (the want of a proper mining survey and working plans is here painfully apparent) — to lie south abreast, or already a little beyond, beneath the bottom of the previously mentioned shaft — the last one hundred feet having at the rate of £8 to £10 per foot been driven E. in the line of a flat slide which he took, from its position, to represent the continuation of the flat reef left in the shaft ; and in this supposition he seemed to all appearance to be correct. But if so — considering that only few small pockets of rich gold-bearing quartz had been met with in the slide along the whole distance, and that moreover but a small stream of water had made its appearance in the face, though there were nearly 60 feet of water standing in the shaft above — the prospects of the flat reef at that depth appeared to be far more cheeiing. On the supposition of its forming a block dipping from" the shaft eastward in strike, there was no doubt still the chance of its being found of some thickness further a-head ; however, in looking at the uncertainty and the expense of farther work, I advised the manager to discontinue driving on the slide altogether, and instead to open out eastward on a quartz reef, 9 inches thick and dipping vertical, which crosses the adit E. and W. some distance from its mouth, and in which, gold 'is said to have been found when penetrated. In fact, there can hardly be a doubt that this reef represents the continuation of the main reef, worked at the surface ; for besides having the same strike and dip, its position in the adit — as ascertained by tape measurement — agrees tolerably well with that of the main reef, as given on a plan prepared by Mr Evans, mining engineer, on which also a good length of the adit is marked. As regards the prospects of the proposed workings, I think they are very fair, judging from the character of the reef jat the surface, and that gold has already been found in the portion crossing the adit ; but it must not be forgotten that, as soon as the available backs are worked out, opening of the reef in depth, will have to be effected by shaft, and requires pumping and hoisting machinery. The flat reef may either be a so-called " dropper," or represent a reef parallel in strike to the main reef, which, on crossing the latter in depth, shifted it a little southward; still, whatever its nature, I take it, to be uncertain in extent and auriferous character. The portion left in the. shaft might perhaps be easiest opened by a rise from the end of the adit. Touching the crushing machine of the Company, it consists of five heads of revolving stamps driven by a turbine, copper-plate-table-and blanket-strakes ; a rippled tailingrace forming not a bad addition. Golden Crown Reef.— This is apparently a continuation of Logan's Beef, from which it lies about l£ mile distant to the east. The discoverers, J. Wrightson and Co., have not done much, work on it as yet ; but from, what it disclosed, it seems to be of a mullocky character, and from 9to 16 inches thick. A crushing of 17 tons yielded about 8 dwt of gold per ton,- ' ' j Claim No. 10.. — This lies also in the line of, and about 2 miles distant from,

Logan's Reef. It contains a well-defined quartz reef, from 2 to 4 feet wide, in which superficial prospecting has not disclosed any gold as yet; but near to this reef, on the south, and dipping towards it }> runs a parallel from 6to 10 inches thick, from which a crushing of 26 tons produced at the rate of 26 dwt of gold per ton. The reef deserves, in my opinion, to be properly prospected. (To he continued.)