Inquiry Told Old Slip May, Have Caused Collapse

Press, Volume CX, Issue 32320, 11 June 1970, Page 30

Inquiry Told Old Slip May, Have Caused Collapse

(New Zealand Press Association) HAMILTON, June 10. The theory that an old slip not visible from the surface could have caused the total collapse of the Kaimai Tunnel towards the face was introduced in Hamilton today by the construction superintendent on the project, Leonard Irwin Wills.

He was giving evidence before the Commission of Inquiry into, the collapse of February 24.

The commission comprises Messrs A. W. Ydrtt (chairman), K. E. Andrews and F. J Hancock. Four parties are involved in the inquiry: The Ministry of Works (Mr J. D. Rabone), the Public Service ! Association (Mr J. D. Bath(gate), the New Zealand Workers’ Union (Mr N. 1. Smith) and the Department of Mines (Mr V. R. Jamieson). Mr Wills said that late on February 25 a hole had appeared in front of the face the draglines were working during rescue operations. SLIP CIRCLE

The hole appeared to him to be part of a slip circle and ran downwards towards the tunnel face at a 45 degree angle for 20 feet or more. (This hole was used to sink the 32in diaitieter steel rescue shaft to the trapped men.) Mr Wills said the cavity might have been an old slip which had not been evident from the surface. “If so it could be the prime factor in the total collapse towards the face,” he said. “I cannot state any specific reasons to account for the sudden, massive collapse over such an extensive area ”

Up to and including his visit to the tunnel on the morning of the disaster there had been no visible evidence of crushing, settlement or distortion of timber, to suggest that earth movement was taking place in the area of the fall.

“Evidence, however, points to the fact that a run of material was going on for some time before the sudden collapse of the support timber,” he said. “In my opinion this run was the prime reason for the sudden failure of the section that collapsed.” Replying to Mr Rabone, he advocated the introduction of

brochures giving safety notes and emergency instructions for tunnellers. Before the collapse there had been no definite instruction to the men on what they should do in an emergency. “Newcomers were placed with experienced men and were expected to learn as they went,” he said. However, a safety system had been in progress before the cave-in. All workers on the site had received instruc-

tion in the use of Minuteman resuscitators. The National Safety Association had been contacted with a view to instituting a safety programme. Each shift had a fully qualified first aid man. Mr Wills said the Kaimai project would have the highest rate of experienced tunnellers of any job in New Zealand. “Thirty-three pei cent of the tunnellers on each shift are ticketed with either A or B grade certifi cates,” he said. NINTH WITNESS Mr Wills, who will resume [ his evidence tomorrow, was the ninth witness to testify today. The others, all tun nellers, including one survivor of the fall, two over seers and two shift bosses, gave further accounts of conditions in the tunnel before the major collapse. Maurice Anderson, the shift boss on the 4 p.m. to midnight shift on February 23, said that as his men had been polling back towards the portal that day there had been a bit of a run, which had been packed off with timber. Patrick Geany, on the same shift, told of an incipient fall of sludgy material on the; face the men were working. The material had included! some grass. Two of the tunnellers,, Neville Raymond Bliss, the j shift overseer, and Bernard Arthur Walker, gave eyi-l

dence of hearing talk on the site before Christmas about drag-lining the overburden from above the portal to make an open cut. Mr Walker described a fall about three weeks before the disaster. He said it had filled a muck waggon and overflowed, and had left a hole in the surface, five to six feet across. The fall was about 46 feet in from the portal.