AT ONE BLAST.

Otaki Mail, 3 October 1923, Page 4

AT ONE BLAST.

9000 TONS OF METAL FOR ROAD IN (i At a. cost of about £SOO some 9000 tons of solid rock, which stood on the banks of the Waikato River, between Mercer and Tuakau, was broken up recently at one blast. The metal obtained "as a result, of this operation { is to be used for road formation, and particularly in connection with the work at Rangiriri. Before the actual firing of the charge which loosened so much valuable metal, there was much preliminary work l , extending over several weeks, that had to be carried out. The solid rock had to he penetrated by a drive 45ft dei p and three feet wide. For about five feet on either side of the main tunnel a cross-drive was made, and in it if e explosives, about a. ton in weight, and sealed with concrete, were placed. Considerable interest was manifested in (he final act which would bring the mass crumbling clown. A number of launches journeyed Tom Me.-;:r to Tuakau, and spectators w-* v landed on the other side of R e rlve r . -v! ere a good view of the proceedings could be obtained, while at the same time safety could be observed. The current was switched on from behind the quarry and the hill was seen to heave. The next instant there was a. brilliant flash and a deafening exI plosion and then a shower of small 1 stones shot, up to fail into the river A number fell among the spectators -. on the opposite banks, a distance of ’ nearly 300 yards. On examination it was found that the whole face of the bluff, which was GOft to 80ft in height and several chains in breadth and I depth, had been opened. As the result I of the big explosion onlv small shots , win he required in future quarrying.