WAIPORI EXTENSION

Evening Star, Issue 20059, 27 December 1928, Page 10

WAIPORI EXTENSION

IMPORTANT WORK IH HAND FIXING SLUICE VALVE IN TUNNEL Important work in connection with the extension of the Waipori electric power system is at present being carried out This is tbe_ fixing of a 57m diameter sluice valve in the main tunnel, which is above the Waipori Falls power, station. _ . The work entailed tho sinking ot a. shaft from the side of the hill by 100 ft above the tunned, and the lining of the shaft with concrete to a level of some few feet above the crown of the tunnel. During the holidays a bulk-head was put in across the tunnel above the point where the shaft will intersect it. This bulk-head was put in position on the night of December 23, and since then work has been carried out continuously in excavating the ground in order to break through to the tunnel and in dynamiting the rock so as to construct the valve chamber. It if hoped to finish the work about January 2 or 3. Briefly, the object of tho valve is to enable the tunnel to be worked under pressure. The tunnel will bo able to he worked with a higher head of water than was formerly the case, the efficiency of tho head works thus being considerably improved. . The work of raising the dam at M aipori is also being carried,, advantage being taken of the lessor amount of water being used just now to get a temporary coffer dam across the river. That'will be finished within a week, good progress having been made with the work. Previously this work could bo done only on week-ends, when tho power demand was low and when not much water was in tho river. Floods, however, during week-ends necessarily stopped the work; The present fino weather and the holidays allow better progress to ho made.