Explosion in grain silo rocks Timaru

Press, 4 January 1980, Page 2

Explosion in grain silo rocks Timaru

Timaru reporter Parts of Timaru . were rocked yesterday when a grain silo at the Timaru waterfront exploded and blew a nine-tonne conical roof 100 metres into the harbour, and shattered shop windows.

The roof, 12m in circumference, narrowly missed 13 moored fishing boats. Overheating for the last week, the $200,000 silo was being emptied of lucerne pellets when the explosion occurred. Six Timaru Harbour Board and waterside workers were under the silo when it exploded at 10.13 a.m., but scrambled to safety.

One man was taken to hospital with suspected eardrum damage, but was later discharged. There were no other injuries. Onlookers described the incident as frightening.

"It was sucked in first and then the roof came off and was blown into the harbour,’’ said Mr A. C. Bleeker. "It was like a mushroom from an atomic explosion,” said another onlooker. The Fire Service at Timaru sent three engines, including a snorkel. The Chief Fire Officer (Mr R. G. Carlaw) said no attempt was made to extinguish the fire from the top of the burning silo because the top layer of lucerne was a “gooey mess.” The quickest and easiest way was to discharge it from the bottom, and a fire crew dampened the lucerne down before it was loaded on to a truck. “The lucerne has been on fire for a week,” said Mr Carlaw.

The brigade had received a call the previous Fridaymorning. “We suspected it was burning right down inside: we thought on the bottom because of overheating,” said Mr Carlaw. He had asked for a report from Fletcher Agriculture, of Ashburton, and the matter had been placed in the hands of the Timaru Harbour Board.

In the last few days the board had been discharging the lucerne and -transferring it to a section Opposite the slipway. The. explosion was caused by one of two things, said Mr Carlaw. It could have been a dust explosion or an accumulation of un-. burnt vapours. “We consider that when lucerne pellets are burning they coagulate and form, into great lumps. As free-running pellets ove away they build into pyramids — stalagmites — and after a while collapse,” he said. It was possible that it was this collapse which had caused the dust in the silo being ignited

by the embers of the burning lucerne. The second possibility was an accumulation of unburnt vapours released by burning lucerne which had heaped up in the top of the silo, and as it had been drained it had been replaced by air at the top which had gradually built up an explosive mixture with the unburnt gases. “We will carry out a full investigation, but it is idoubtful whether we will be ■able to find an answer for ■the explosion,”, said Mr Carilaw. “A lot of pressure , was ! built up in there. The con‘iveyer belt would weigh sevjeral tonnes, as would the itop, and a fair weight was' being thrown about,” he said. There was now no danger, as the silo was freely ventilating from the top. Employees at Averis and Box, Ltd, automotive electricians, were having a cup of tea at the time. The explosion sounded to them like a “big, dull boom,” and clouds of smoke were seen pouring from the silo “like a rogue bore.” Mr R. G. Meldrum, a former serviceman, of Dunedin, said the explosion sounded like a big gun. “I saw it- sailing through the air, at least three times as high as the silo. The rest of the gear went in the opposite direction. I thought: ‘A couple of land mines in the wrong place’,” said Mr Meldrum.

A railways signalman was in his signal box near the overhead crossing and to him it was like an earthquake — “a rumbling noise, and then an explosion,” he said. The noise was caused by the conveyer- belt falling. A group of men, including the person who was later taken to hospital, had been working beneath the silo. They were having morning tea.

The five men in the immediate vicinity of the silo saw a cloud on the top, then felt the ground "reverberate.” Mr W. MacDonald was six metres up on a dust extractor of another silo when the shock wave blew his feet out from underneath him. He clung on by his fingertips and managed to regain his footing. Mr T. Bleeker, who was contracted to move the lucerne from the silo to the stockpile was beneath the silo with his two sons. He was wearing clogs. “Smoke issued from the: bottom of the silo like a jet and we started ■ running. I heard a muffled bang. It sounded like a big explosion,” he said. There were pipe and pieces falling in all directions and the top was at least nine metres in the air he said. Both sons, Messrs A-. C. and G. J. Bleeker, saw the top "rushing through the air” in erratic wind-assisted flight and falj into the harbour. :<!.

A cone-shaped piece of wreckage consisting of 3/16 inch plate deposited against the rocks and only a short distance away from six fishing boats. . A section from the threetonne drag-conveyer which had fitted into the top of the silo lies near a dinghy which is attached by line to the trawler Stella Marie. Mr T. Bleeker said that at times during the last few days red-hot pieces of lucerne were being removed from the bottom of the silo. Some doubts have been expressed locally at the wisdom of having lucerne stored in built-up areas. Silvery-grey smoke was still issuing from the sild late yesterday. It resembled a rocket without its nose cone.