DREDGE ACCIDENT

Grey River Argus, 17 December 1943, Page 6

DREDGE ACCIDENT

Ngahere Stackerman’s Death INQUEST AT GREYMOUTH Before the Coroner, Mr G. G. Chisholm, at Greyimouth _ yesterday an inquest was concluded concerning the death of Henry Hugh McKenzie Taggart, a stackerman. After hearing the evidence the Coroner returned a verdict that the cause of death was shock due to crushing injuries received by Taggart when the screen of the Ngahere dredge was set in motion while he was working upon it on November 25. Senior Sergeant G. H. L. Holt conducted proceedings. Taggart’s relations were represented by Mr W. D. Taylor, the Ngahere Gold Dredging Co. by Mr J. W. Hannan, the Dredge Workers’ Union by Mr J. Laing, and the Mines Departinent by Mr G. W. Lowes.

Dr B. H. S. Aylward, of Blackball, said that when examined at the dredge Taggart was badly shocked and complained of a violent pain in the small of the back and loss of sensation in the lower limbs. Witness suspected a fracture of the spine. He injected morphia and supplied warmth in treatment for shock, but Taggart rapidly became worse and was dying when the ambulance arrived. Witness considered the cause of death was shock from the injuries he had received. Edward William Holmes, supervising engineer on the dredge, said that on the morning of the accident the dredge ceased work at 7.10 a.m. because of a burnt motor. Taggart was one of four men told to attend to the removal of. a faulty plate on the screen. Taggart was responsible for the safety of the motive power supplying the screen, and witness presumed that he would release the oil switch circuit breaker before the work on the screen was started. There was no necessity to operate the screen by power to any desired position to have the screen removed. At 8 a.m. witness heard the screen start up, and yells from the direction of the screen. He opened the distributor door, looked under the screen and saw Taggart lying, on the bottom of the casing below the screen, free of it and well clear. A section was removed from the the screen so that Taggart could be moved out. The accident could have occurred through a possible fault in the electrical equipment or through some person operating the control buttons while the oil switch breakei’ was still not removed.

To Mr Taylor: He could not say whether Taggart was .ever told to cut off the power before working on the screens. To Mr Hannan: He knew that on previous occasions when- work h.ad been done on the screens Taggart had cut off the power at the circu’t breaker.

James Philip Griffin, dredgemaster, said that when he arrived he heard yells and learned of a man being caught on the screen, from which he was extricated after about an hour’s difficult work. The screen weighed 40 tons and there were only four inches of clearance between the flanges on the screen plates and the side of the casing. Deceased’s body was crushed through this space. The routine of repairs was that the stackerman (in this ease deceased) placed the screen in position ancj, then pulled the oil circuit breaker switch which isolated the screen motor. On the present occasion the breaker switch was not pulled. Deceased was always careful in complying with these instructions on previous occasions. He had had considerable dredging experience. Wilfred Cecil Mcßoberts, welder, said that as the screen began to move he noticed deceased was caught, but before he could assist him he was dragged ithrougfhi. Witness called to have the screen stopped and witness assisted to cut out a plate in the screen to get deceased out. Deceased was conscious, but simply spoke of his injury. , » x * j John Meikle. winchman, stated that while at the instrument board known as the panel, he heard a yell and the screen in motion. He rushnd to the circuit-breaker and stopped the screen He would be about 20 to 25 feet from the control buttons when the screen started and, about the same distance, in a direct line from the circuit-breaker, but he had to go down the stairs, which made it further. Because it was his duty to put out circuit-breakers he rushed straight for the breaker rather for the control button.. Tn Mr. Hannan: About the time of the accident he did not see anyone else in the vicinity of the panel or the control button. To Mr. Lowes: It would have been much shorter for him to run to the push-button than to the breaker. As he was standing at the panel he heard a grating noise which he

thought was the switch clicking in. > Mr. Lowes: We know definitely that someone pressed the button that started the motor. What we are trying to find out is who did it. Witness said he did not see anyI one near the controls. He ran to I the breaker instinctively as he used the breakers so frequently. He did not see anyone at the control room who could have operated the switch. If anyone was working on the screen the breaker definitely must be out. It was customary for men working on the screen to put it out. Duncan Hugh Rae, electrician on the dredge, said it was possible co start the motor from the -control panel by pushing in the contact magnet armature by, hand. The control panel was not' locked. After the man had been removed from the screen witness closed the circuit breaker to ascertain whether the motor would then operate and it would not. It was possible for a fault to cause the motor to operate immediately the circuit breaker was closed, but his test did not show that. He uncoupled the motor but did not find the actual fault. The fault could not have caused the motor suddenly to operate. To Mr. Taylor: Mr. Davenport, the Resident Electrical Engineer, Public Works Department and an electrical inspector made a complete test of the control gear and the motor and as far as he knew they found no indication of an electrical fault. The buttons in the control room were three-eighths of an inch from the casing and to start the motor they had be be depressed be-' yond the casing. He did not think the screens could be started by anyone leaning against the buttons. For a man to start the motor at the panel the panel would have to be open. When witness first went to the panel after the accident it was closed.

Arthur Egbert Davenport, Resident Electrical Engineer, Public Works Department, stated he made a thorough test of the electrical equipment of the screen motor jointly with Wilfred Francis O'Caliuhan, an electrical inspector of Christchurch, on the day of the accident. There was a smell of burning in the motor but instrument tests snpwed no fault currents could pass from the motor winding to the frame of the machine in the condition of the machine at the time of the examination. A thorough visual examination and all possible instrument tests on the screen motor control apparatus showed that this was then in perfect condition and trials with the electric power on the controls but disconnected from the motor proved the controls functioned in a proper manner. In the case of the push-but-ton control it was found by trial that the reverse button could be caused to make contact and thus operate the motor by the pressure of the point of a knee or bv a kick by the toe of a boot. In anyi. case the button must be depressed below the level of its protective shroud to make contact. To Mr. Taylor: The net result of the tests was that no electrical cause was found for the starting up of the screen. There was a possibility of any metal object, which would have to'be at least an inch long, bridging a pair of contacts. It was highly unlikelv that a falling screw from the equipment itself could bridge the contacts. Examination of the whole of the equipment belonging to the panel failed to disclose any missing screw, bolt or any oiner part of the equipment. He found a broken screw in the bottom of the case as if laid there when a replacement was made on a previous occasion. There were no screws missing in the panel. A routine examination was made two days before the accident by Mr. O’Callahan, but in that examination it was not the duty of the inspector to inspect the screen motor or its controls. He regarded the pushbuttons as safe, as they stood. They were the normal type of equipment. It would be advisable to have the circuit breaker locked when it was in the isolated position while men were working on the screens.