WAITAHUNA COPPER MINE.

Tuapeka Times, Volume 27, Issue 950, 27 June 1883, Page 5

WAITAHUNA COPPER MINE.

The following is ' Professor Ulrich's report of his recent visit of inspection to the Waitahuna Copper Co.'s works :— To Geo. Watson, Esq., Dunedin. Dear Sir, — According to promij*, I beg to furnish you, for the information of the Company, with a report of the results of mr recent examination of the 'orb deposit of the Waitahuna Copper-mint. Sating, before my Tisit to the mine, beon under the impression, from published reports and conversations with miners, .that the ore deposit was a genuine lode travening the country, I was much surprised in finding that this idea, is quite erroneous. The deposit really represents a laytr or bed ot ore standing to its enclosing rork (an argillaceous mica schist, abundantly interlaminated with quartz) in- a similar relation as a coal-seam does to its enclosing rock— namely, its strike and dip are coincident with those of the schist beds between which it lies ; it will not penetrate them, but be subject in its extent to the same changes— bends and rolls— these may exhibit in strike and dip. In tbe underlay shaft, following the deposit 90ft in . its dip southward, I found, its strike to be W. lOdeg. S. to E. lOdt*. N. and its dip 8. lOdeg. B. at an angle of 23}deg. ; but these .figures may, iof course, alter— i.e., for instance, the dip may become flatter or steeper, or eren bo. re rersed, according to corresponding ohanges in the lay of tbe rock.. Ju.dgipg.from surface outcrops of the latter, a short distance (B*4 chaics) r souf h of the shaft, on the banks of .the Waitahuna River, it is indeed not improbable that from there the schist rook, and therewith the or«-bed, will' commence to rise southward ; sirioVif this happens, the low-lerel being driven from the shaft in that direction will neyer strike the ore-bid, but run underneath it, except its< dip be again reversed to the present direction. The ore may, of course, be reached -from the lower level by breaking overhead ; but cdnsjderinf the expense and time involved in driving the lore', say, only 100 ft farther, before attacking the qeposit in this way, I should, rather advise to stop it for the present, and drive instead from the 39ft level on the course of the ore-layer eastward (E. 10 N.) T ».e., from the point where the main shaft intersects the ore ; for there is every probability that th« layer extends in that direction." Every foot driven will therefore yield ore, and the farther the latter is thus followed into the .range the more of it will there be; available overhead northward for stopping. Orerlayers are, from experience, liable to alter in thick* ness, generally more so than, lodes ; they may thin out for some distanc* in strike and dip, and recommence, s again, attaining, ..perhaps a greater thickaess than before. The Waitahuna. layer, as. far ss 'tbe workings expose it, ranges.. in. thickness' from. a few incbJM to about Jft. Taking its at^rage thickness to be lft, and that about 10 cubic feet of the ore (which is an intimate mixture of iron and copper pyrites) Weigh one ton, it is dear that a 'block of ground of 100 ft square stopped out would produce 10,000 cubic foet, equal to 1000 tons of ore, which, at the price youitold me the ore, it containing 15 per .cent, of copper, could be sold fer, should leave *. handsome prqflt over working and transport ex« penses. As regards a change in the quality of tbe ore for better or worse, this is a contingency which in ore,-layore is not so frequent as in ore-lodes; but 'you must be prepared for haying to dr* ss the ore up to standard if, what is nob unlikely to happen, laminations or thin layers of pure iron pyrites occur on top or at the bottom of it. What may possibly cause you some trouble in tbe working of the deposit is the occurrence of faults, occasioned by clay slides, or, as is more frequently the case in schist fockf, by small veins of iron pyrites. Another point of great importance I wish to draw your attention to is that there is great probability, if not certainty, of the, ore-layer extending, into the hill west of the Waitahuna River. Therefore I should sto-ongly recommend to carefully prospect that side up the river from the p<lnl where you told me some .ore. was found years ago, and should— what I do. not doubt —the continuation of tbe deposit be proved, it might possibly be workable by' means of an adit out of reach of floods in 'the river.

As showing the importance of ore-layers in genera), I may. in conclusion remark tliafc the ore deposits .of' many celebrated mines in different countries are of this clase. Especially noteworthy are Beyers 1 copper-mines in Tyrol, which rank amongst the daepeit in the world. ' Nearer home nay be instanced the Peak Downs Copper-mine, in Queensland, and several copper-mines in New Caledonia.— I am, 4c, GteoßGß H. F. Uleick.