ARAPUNI POWER WORKS

New Zealand Times, Volume LIII, Issue 12509, 27 July 1926, Page 3

ARAPUNI POWER WORKS

WAIKATO RIVCR DIVERTED SUCCESSFUL EXPLOSION. Per Press Association. HAMILTON. July 26. * The second shot at the Arapuni hy-dro-electric power works which blew in a huge lip of rock an the bank of the Waikato river at the entrance to the inlet of the tunnel was fired toI day. The explosions of nine days ago were merely for the purpose cf removing the crown at this inlet, and to permit a certain flow cf water through the tunnel in order to form a cushion of water to take the concussion in blowing out the rock bank at the outlet. which consisted of several thousands tons of material. Severn! thousand tons of rock were left at the inlet, which,, if blown out originally, might have caused a jamb of rock and debris at the entrance to the tunnel before the water commenced to flow freely along its new course. To-day the remaining embankment of rock was sent skywards by a charge of 2’ tons of blasting gelatine. This effectively blocked the old course of the stream, and caused the whole flow of the river to pass through the diversion tunnel. Thus was the first stage of the undertaking accomplished, leaving the dry bed of the river at the site where the dam will be constructed so that the work may proceed unhampered by the presence of water. As a safeguard to the workmen against a sudden rise of the river a subsidiary dam. made of gabions, is being constructed on the upstream side, while a further coffer dam will be necessary above the tunnel outlet as a precaution against backwash.