DOBSON MINE.

Press, Volume LXIII, Issue 19026, 14 June 1927, Page 9

DOBSON MINE.

CAUSE OF EXPLOSION.

FURTHER EVIDENCE AT ENQUIRY.

(special to the press.) GKEYMOUTH, June 33. The Royal Commission appointed to enquire into the disaster at the Dobson Mine completed its third day's sitting to-day. Further evidence was submitted in regard to the quantity of coal dust which was stated to have been accumulating in the mine prior to tho explosion. Evidence was also given to the effect that experiments made recently by Messrs J. Hughes (manager), and J. Smeaton (president of the Grey Valley Miners' Union) revealed the possibility of extracting batteries from electric lamps and causing them to explode with the use of detonators, thus making it possible for shots to be fired by that method. During his evidence this afternoon the mine manager, Mr J. Hughes, expressed the opinion that the explosion originated in the rise workings, and that it may have been caused through coal becoming heated, a defective safety lamp, or a fall from tho roof causing sparks to ignite an accumulation of gas.

Dust Very Thick.

John Bullock, a miner, employed on the day shift in No. 2 dip on December 2nd last, said that during the week before the explosion, the place was very dusty and he reported it to Griffiths, who was then acting as shot-firer. The dust was so thick that witness could hardly see his mates. The air coming through the pipes was not sufficient to remove the dust from the working place. He made a practice of testing his place three or four times a day with an oil safety lamp, but found no traces of gas. After he complained about the dust, clay was put down. Dobson was not as gaseous as some of the mines he had worked in. Two months before the explosion the No. 2 dip was dusty, but not so bad as it was just before the explosion. He then complained that there was no ventilation pipe, and said ho would not work there unless one was put in. Leitch never complained to witness about hanging his oil lamp on a jig post. Loitch might have warned his mate about the lamp. Dobson was the first mine where he had seen air pipes used in preference to brattice. He had been working at Dobson for about 18 months, but he did not see any steps taken to deal with tho dust until the week before the .disaster when clay was put down. The clay stopped the dust on the floor from spreading, but nothing was done to the roof or sides. He had sometimes thrown water over his place to make it more comfortable to work in. It was not the practice of miners to complain to mining inspectors. The latter were supposed to see things for themselves. He also told the secretary of the Union about the dust.

"Full of Gas."

James- Blanche, who was Eeid's workmate in the rise section on December 2nd, said that gas was not noticed before 9 p.m. A safety lamp waa forgotton that night because : they had iools to carry into the mine, but he had not made a practice of going without the lamp. While Lhey were putting up a prop, Reid said that the place was full of gas. They reported to the deputy (Little), but the latter accused witness of wanting to get away early. Witness offered to go back with Little to test : the gas, but Little said he was too busy. There were no ventilation pipes in the rise. Little had visited the place throe times that night, but did not make a proper inspection, not going beyond the working place. Witness was sure Reid brought the safety lamp he had borrowed from the Italians out' after making the inspection. ,

Shot-firing.

'Walter Dando, deputy, said lie acted as shot-firer. On December 2nd lie visited Eeid's place at 10.5 p.m. He put Mb lamp to the roof in order to examine the fault, but could find no trace of gas. He had refused to fire shots that were not properly prepared. Witness had regarded Dobson as the safest mine in New Zealand.' Witness was in the lamp cabin when Eeid told him about the gas. He was not present when the complaint of gas was made to Little.

Testing for Gas,

I. A. James, superintendent of the State mines, who was recalled, repeated his opinion that the explosion took place in ihe rise workings. He described the methods of stone-dusting a mine, which was applied in the form of a lime wash, but it was used more to illuminate the sides than as protection from coal dust. In a gaseous mine he favoured the man in charge of each working face being able to test for gas. If that man was not given a safety lamp the tests could be made by the various officials on their frequent visits. He would not allow men to work in 2 per cent, of gaß, although the law stipulated that 2| per cent, of gas must be present before men were ordered out. Two per cent, of gas would be dangerous for shot-firing in a place which was dusty. Oil lamps were generally hung up on props, and therefore became dangerous when neglected. A practical man could detect gas without making a test by a lamp. In his opinion gas started the Dobson mine explosion, and the eoal dust carried it through the mine. If the electrical plant were erected in accordance with the regulations it should be quite safe.

Beporting a Complaint.

George Little, deputy, recalled, said that when Eeid made his complaint it was practically knock-off time. As there were no men working in the place that night he considered that the reporting of Eeid's complaint to Deputy Richards was sufficient. '

Electrical Installation.

On resuming after the luncheon adjournment, evidence was given by James Stanley Langford, electrical engineer, concerning the electrical installation at the Dobson Mine. The installation, he said, was capable of carrying an extra- load of 50 per cent, above the Mines Act's requirements. The whole apparatus carried a guarantee under special tests made at the Sheffield University of being proof against explosions. The test was recognised by the British Board of Trade. Witness described the mechanism of the motor, and stated that in his opinion it was impossible for it to generate sparks or flame. There had evidently been trouble with the switch, which was designed particularly for use on portable apparatus. So far as witness knew, repairs were effected prior to the visit of the inspector a fortnight or three weeks prior to the explosion. Witness had received no complaints that the underground apparatus was de fective. About a fortnight before the explosion the manager had communicated with witness to the effect that the coal dust was increasing in the bottom dip, and he would like to consult with witness.

Trouble ■with SwitchCharles William Payne said that np :o the time of the explosion he was he electrical engineer at the Dobson

Mine. He remembered the trouble with the electric switch. The motor ran without any trouble until the explosion. From his point of view it was an absolute impossibility for sparks or flame to be seen coming from the motor. Witness said he thought tin air brake switch would bo safer in a coal mine, provided it was properly enclosed. After the explosion ho'examined the oireuit and found it in good r>rder. Tho switch at Dobshn had only >een affected on one occasion. Ho had not heard any of the men mention that sparks and flame shot out from the motor.

Mine Manager's Evidence,

Job Hughes, manager of tho Dobson Mine, said lie was acting-manager of the mine in Mr Leitch's absence when the explosion occurred. He had altogether 2" years' coalmining experience, and for 15 years had been managing collieries in various parts of New Zealand. He inspected practically the whole of the underground works at Dobson on December 2nd, in company with Deputy Griffiths. Ho found that the ventilation on that day was particularly good. There was a slight accumulation of gas in Brammer 's place, which was eleared in five minutes by the ventilation pipes. The inspection on that day took from 8.30 a.m. to 1 p.m. He was in tiie mine also about 7 o'clock in the evening, when Deputy Littlo reported "All well." From what ho saw subsequent to the first explosion, and since tho dowaiering operations were completed, he was of the opinion that the line of force came from the rise workings. Possibly the explosion could result from the coal becoming heated, or from sparks being omitted through a fall from the roof, or through a leaky safety lamp being left in the mine. He disagreed with the theory that the explosion originated in Brammer's place, which was regarded as a damp place. Nqake's place was also damp. He considered that the ventilation was good.

Abating Ooal Dust.

A few days prior to the explosion he issued instructions that adequate ventilation must be provided in the working places. The coal dust was assuming dangerous proportions in some parts of the mine. On the Saturday prior to the explosion he ordered clay to be applied to the top portion of the floor of No. 2 dip to cover the coal dust. He discussed the question of coal dust with the Chief Inspector of Mines. Instructions were given that improperly prepared shots were not to be fired. When ho made his inspection on December 2nd he drew the shotfirer's attention to an improperly prepared shot that had been fired in Brammer's place. He was assured that the cover enclosing the switch was flameproof. It was possible that an accumulation of gas could .have generated quickly in Keid's place. In his opinion the dust in Canten's level was dangerous. He would not say that coal dust in other parts of the mine was dangerous. He thought coal gas in the mine propagated the explosion. The dust had been becoming more dangerous for some months prior to the explosion. He was satisfied that a mine like the Dobson mine should be effectively stone-dusted. He did not see any reason why workman's inspectors should not be present when samples of coal dust were taken. There was a possibility of an ignit'on by falling stone in Eeid 's place if there was a sufficient accumulation of gas. The roof in that place was hard. A "goaf" area was sometimes too unsafe for a deputy to inspect. He thought motors should be installed in places where there was no possibility of gas accumulating.

Most Dangerous Duty.

Witness said that when firing a shot a deputy was performing the most dangerous duty in the mine. When he went to fire shots he was expected to see to the ventilation of the working places. The reason why the mine was employing an additional underviewelr was to fulfil the requirement's of the Mines Act. An underviewer would relieve the deputy of a certain amount of responsibility. The safety lamps, to witness's knowledge, were not checked when issued or returned. He thought the initial explosion was caused by gas ignition and carried through tho mine by coal dust. The line of force appeared to have come from east to west. He thought that it may have originated in No. 5 or 6 rise headings, or in No. 2 dip.

Not Given Free Hand.

In reply to Mr Kimbell, witneßs said tnere was nothing done to prevent coal dust accumulating in the mine except in the case where clay was spread in No. 2 dip. Ho expressed the opinion that that particular section of the Act should have been complied with. The reason why steps, were not taken to stone-dust the mine was because he was acting as manager, and had received no instructions from the general manager, Mr Leitch, to do ao. He had a free hand in the management of the mine to a certain extent. Eegarding Regulation 182, in connexion with safety lamps, he found tho practice of not checking was in vogue when ho came to the mine, and he had not taken steps to alter the custom. In regard to Section 98, sub-section 2, regarding [searching the men for tobacco and matches, he had not conducted any search, but understood that the men had been searched on one occasion by the exmanager, Mr Hunter. Witness stated that Regulation 242 B, with regard to i grunching, appeared to be ambiguous. It should state the depth required for cutting a shot. Witness did not remember having been told by the chairman, of directors, Mr A. Smith, that he was in sole charge of tho mine, during the absence of the general manager, Mr W. Leitch, on sick leave. He denied being given a free hand in connexion with conducting the mine. He had mentioned the advisability of taking samples of coal dust to ifche directors. From subsequent experiments witness and J. Smeaton had carried out it was found that wires could be extracted from lamps and exploded with a detonator. It was hardly feasible that any miner would resort to this practice as a shot-firer was always on shift and visiting tho various working places in the mine. The ventilation of the mine was attended to by shiftmen. The hearing was then adjourned until to-morrow at 10 a.m.