MINING NEWS

New Zealand Herald, Volume LXXIII, Issue 22464, 7 July 1936, Page 5

MINING NEWS

BLACKWATER OPERATIONS

HIGHER PROFIT IN 193S

DEVELOPMENT AT DEPTH

[from our own correspondent]

By Air Mai! LONDON, June 20

Net profits of Blackwater Mines, Limited (Reefton). for 1935, were £41,'144, against £31,578 earned in 1934. Dividend of 15 per cent for the year requires £37.498 and £20.000 is transferred to general reserve. Against £24,238 brought forward, £BIB4 is carried forward.

Speaking at the annual meeting in London, Mr. L. Ehrlieh, chairman of directors, said the quantity of ore milled was 45,660 ton?, of an average value of 9.33dwt. a ton, from which an extraction of 92.60 per cent was obtained. The yield from the ore milled was 19,7270z. fine gold, which realised an average price of 141s lid, against 140s 7d in 1934. The total realised value of gold won during the year was £139,953, or 61s 3Jcl a ton. All-in working costs for the year, including mine development and gold duty, amounted to £76,757, or 33s 7Jd a ton, leaving a working profit of £63,196, or 27s 8d a ton.

Formerly the company had not included in working costs a charge for mine development, hut it had adopted this practice in the present accounts, Mr. Ehrlieh said. This represented a charge of 3s 9d a ton. For the year the grade of ore was lower by 4s 9d a ton compared with the previous year, when "cleaning up" operations from certain parts of the mine yielded some higher grade ore which "sweetened" the grade of ore to the mill. Allowing for this, and adding the appropriate charge for development against the tonnage treated in 1934, there was an actual reduction in working costs for the year 1935 of a little over 9d a ton. The Prohibition Shaft Mine developments had been retarded by the sinking of, and repairs to, the Prohibition shaft. The total development footage amounted to 2499 ft. Of this total, 1184 ft. was driven on" reef of which 872 ft., or 74 per cent, was payable, averaging 13.36dwt., over a width of 27.2 in. The major portion of the development was in Ipvel No. 12 north, which was extended 728ift., of which 698 ft., or 94i per cent, was on the reef, and averaged 14.40dwt." over 28.4 in.

According to technical advisers, ore deposits were undoubtedly of deepseated origin and from the geological viewpoint as well as from actual development there was every reason for confidently anticipating the persistence of values and widths to very much greater depths. Subsequent to the period of ore deposition, earth disturbances occurred, resulting ia a series of faults which broke up the deposits to form several distinct oreshoots, which naturally followed the trend or pitch - of the faults/This necessitated the sinking of the Prohibition shaft—located some 2400 ft. north of the Black water shaft —in order to work these orebodies economically at depth. Work was now completed, and the shaft waa in commission and working satisfactorily. The company looked forward with confidence to certain working economies and improved conditions in general as a result of operating through the Prohibition shaft, which now became the main shaft. Improvement in Totanage Mr. Ehrlich said there was no reason to doubt that the improvement in tonnage indicated would bo maintained. The contemplated increase in output was in the neighbourhood of 25 per cent. It had been worked out that orebodies showed consistency to a vertical depth of some 2300 ft. With the complete absence of any adverse geological features, there was every likelihood of their persisting to much greater depths. Little of the ground north and south of present workings had been prospected or explored, but steps would shortly be taken to put this important work in hand.

CONSOLIDATED GOLD FIELDS

NORTH ISLAND OPERATIONS

The intention of Consolidated Goldfields, Limited, to diamond drill in the old Progress Mine, which is about 20 miles from the Blackwater Mine (Reefton), was announced at the annual meeting in London of the company, which is a holding concern in Blackwater Mines, Limited. Mr. L. Ehrlich.. chairman of directors, said the Progress Mine wag operated profitably for many years by the old Progress Company, which won £1,500,000 of gold at, standard price and paid dividends totalling 23s 9d a £1 share. In 1920 operations ceased, owing to the ore body having been cut off in depth and laterally by a large fault dipping at an angle of about 45 degrees and the lack of funds to prosecute the exploration of the ground beyond this fault. The ore body continued strongly and with good valu.e3 right up to the fault, indicating its continuation in the faulted portion on tho other side.

Guided by -various geologists of repute who examined the mine just previous to closing down, as well as more recent geological reports, together with results of a geophysical survey conducted under the direction of the New Zealand Department of Mines, the company had made arrangements with tho New Zealand Government to carry out a diamond drilling campaign in the area beyond the main fault, in the expectation of locating the faulted portion of the orebody. From geological and other data to hand, the prospects were promising. Orders for the diamond drilling equipment would shortly be placed and it was expected that drilling would commence in the course of the next two to\three months. Negotiations were started recently to secure an option on a gold-bearing property in the North Island, and tho early completion" of legal formalities was anticipated, Mr. Ehrlich said. The location and physical characteristics of the property as well as its geological features were favourable. The country rock was an altered andesite, in which occurred a series of fissure veins which could be traced for lone distances. From tho reports and other information submitted, the directors believed that a relatively small amount of development work would prove the existence of substantial tonnages of ore of an average grade of about Bdwt. a ton. The size and extent of the lodes and ore bodies as indicated justified the conclusion that mining operations at the rate of at least 6000 tons a month might eventually materialise. The only risk the company was running was the cost of unwatering and examination, but as the old workings were not extensive or deep that should not be a costJy matter.

YIELDS OF COMPANIES Mataki (Murchison). —Last week, 460z. for 138 hours and 9000 yds. Goldfiekls Dredging (Shotoyer).— lOoz. 19dwt. .for the past fortnight. Golden Sands (West Coast). ~~oz. 18dwt. for 28 shifts of eight hours. Maori Gully (West Coast).—Lasfc week, 50oz. o'dwt. for 131 hours.