GOLD SEARCH IN OTAGO

Press, Volume LXXXIX, Issue 27065, 13 June 1953, Page 6

GOLD SEARCH IN OTAGO

SHOTOVER SCHEME STARTED

DIVERSION TUNNEL BEING DRIVEN A start has been made on a scheme to lower the levels of the Shotover ana Kawarau rivers to expose virgin banks and beds so that they may be explored for gold. A diversion tunnel i s now being driven so that a section of the river near Arthur’s Point may be prepared for the construction of a weir 40 feet high. This weir which is expected to be completed early next year, will enable six miles of the river to its confluence with the Kawarau to be drained m the late autumn and winter. In a few months it is also hoped to start work 20 miles further up.the river at the Branches. Here it Js Panned to build another weir which will facilitate the draining of the river for another 20 miles. ~ The scheme is being sponsored by the Shotover Goldmining Syndicate. Six of the members of the syndicate are Canterbury men, and about 80 per cent, of the finance for the scheme is being provided by Canterbury people. Construction costs ara not expected to exceed £50,000, and costs of work so ,, a r carried out are inside estimates. Mr W. A. Dunstan, of Christchurch, who is in charge of construction, said yesterday that access roads to the Big Beach site and plant sites there had now been completed. The tunnel outlet had been opened, and a start had been made to drive the 250 ft diversion tunnel, which will have a diameter of about 10ft. A Christchurch contractor with long experience in tunnelling expects to tunnel through the rock at the rate of 30 feet a month. The tUnnS‘ I s expected to be completed in about three months, and the draining of about six or seven chains of the river is expected to be achieved soon after. Sealing of River „ Uje river reaches the tunnel outlet it passes through a beach area of about 220 acres, and gravel and other material from the beach will be moved by sluicing to form a bank or barrier about six chains upstream from the tunnel. As the bank is raised the water will be backed up on the beach and will flow into the

Sluicing will probably also be done to remove about 10 feet of overburden xrom the drained section of the riveto expose rock on which the weir will be built. It is thought that the syndicate may And its first gold in this area. Some of the material will be used to form another bank or barrier just above the tunnel to limit seepage from the river downstream. . weir that will subsequently be built will be of a type new to New Zealand. It will be of multiple arch buttress design, capable of taking a

great quantity of water over its crest, and it is claimed to be particularly suited to rivers such as the Shotover that have high flood flows. This typ e of construction also allows econom.ee, in the use of concrete. _ . Mr Dunstan said that it was also hoped to start the second phase oj the scheme—the Branches weir—-m the pext few months. An access roaa six or seven miles long will have w be put in condition for carting materials. The Lakes County nas agreed to maintain this road once has been repaired. This road is pected to be of use to tourists w runholders as well as the sjmaicaie« The completion of the weirs wm make possible the exposure cf banks and bed of the Shotover for miles, and in addition the closing a the gates of the Kawarau dam woui enable the level of the Kawarau to appreciably lowered. At the J.J Beach weir it would be practical* to develop 5000 kilowatts of electrici but at present there are no plans to make use of this potential