136 THE COLLIERY guardian. January 16, 1914. ____________________________________________________________________________________________________ CANTON AUTOMATIC MINE DOOR. The accompanying photograph, represents the Canton automatic mine door, which is extensively used in America for air distribution, and opens automatically when coal tubs or trams—whether- drawn by motors, ropes, horses or ponies, or pushed by hand or when runaway—approach it from either- side. After the train has passed through it closes, thus obviating the necessity for door boys or the persons in charge of the trams running forward to open the doors. A valuable feature in connection with these doors is that, as it is immaterial on which side the pressure of air is exerted, they remain closed on a reversal of the air-current. The importance of this, having regard to recent legislation as to means for reversing the air- current in collieries, mining men will readily recognise. A company known as the American Mine Door Company has achieved great success with these doors in America, and the manager, who is owner of the British patents and rights, desires to interest a limited amount of British capital to launch a British Mine Door Company. He has visited this country, and brought with him two doors which are now in operation on engine planes in Wallsend Colliery, near Newcastle-on- Tyne, where they can be seen in actual operation and are, we understand, giving great satisfaction. Full particulars as to the proposed company can be obtained from Mr. J. B. Atkinson, consulting mining engineer, 9, Kensington-terrace, Newcastle-on-Tyne. _______________________________ Mr. William Fewkes, very well known to members of the coal trade as assistant traffic and mineral manager to the London and North Western Railway Company, is contribut- ing a series of extremely interesting articles to the London and North Western Railway Gazette, recording his recollections of a visit to Ceylon and the Buried Cities in 1903. Exports of By-products in 1913. — The most notable feature of the trade returns for 1913, so far as they concern the exports of coal tar dyes and products, is the increased shipments of benzol and toluol, and tar oil, creosote, &c.:— Coal products, not dyes. Aniline oil & tolui- dine .......(lb.) Anthracene...(lb.) Benzol & toluol (gls.) Carbolic acid (cwt.) Coal tar, erude(cwt.) Coal tar, refined and Quantity. ^912. 1913?~1 1,431,190...1,351,466... 2,938,098... 564,372... 4,607,873. .6,657,135... 152,383... 168,848... 97,428... 104,945... Value. 1912. 1913? 32.438.. . 28,941 7,890... 1,448 191,015... 302,978 209,263... 190,519 18.217.. . 17,852 varnish ...(gals.) 2,294,136...3,095,253... 46,646... 69,236 Naphtha ....(gals.) 680,318... 528,992... 30,526... 24,612 Naphthalene (cwt.) 52,168 86,051... 22,580... 37,665 Pitch ........(cwt.) 9,373,309...9,735,944...1,037,964..1,100,699 Tar oil, creosote, &c. (gals.).............28,668,743.36,758,993... 418,566... 592,539 Other sorts ...(cwt.) 541,739... 702,794... 234,787... 299,163 Total value.... — Coal tar dye stuffs (cwt.) ............ 55,721... Sulphate of am- monia......(tons) 285,043... Muriate of am- monia ......(cwt.) 130,116... — ...2,249,892... 2,665,652 54.849.. . 204,475... 178,914 324,704... 3,991,262... 4,411,920 95.768.. . 161,156... 127,320 The destinations of the exports of sulphate of ammonia are shown below :— 1912. 1913. io Tons. Tons. Japan......... 86,659...114,684 Spain and Canaries ... 66,176... 60,877 Dutch East Indies...... 33,535... 38,046 U.S.A________ 39,033... 37,067 To Brit.W. Indies Germany ... France ..... Italy ....... Other entries. 1912. 1913. Tons. Tons. 8.591.. . 10,050 1.643.. . 9,388 7.665.. . 8,964 13.542.. . 5,822 28.199.. . 39,806 The imports are given in somewhat different form :— Quantity. V alue. Coal tar dyes <-------------*-------\ r----------*-------->. and dye stuffs. 1912. 1913. 1912. 1913.' Cwt. Cwt. £ £ Alizarine & anthracene 61,178... 60,813... 263,723... 272,245 Aniline & naphthalene 283,878...283,027...1,463,679...1,542,545 Synthetic indigo...... 28,302... 23,889... 90,862.. 76,695 Other coal tar dye stuffs 109... 155... 311... 570 Of interest for purposes of comparison are the imports of petroleum and its products. In all, 488,244,598 gallons, valued at .£10,860,184, as compared with 413,333,358 gallons, valued at £7,341,689, in 1912. The imports of crude petro- leum rose from 12,742 gallons in 1912 to 1,109,800 gallons in 1913, whilst those of motor spirit increased from 79,590,155 to 100,982,752 gallons. Other items are as follow :—Lamp oils, 157,141,241 gallons (146,030,093 gallons) ; lubricating oils, 67,974,533 gallons (65,327,061 gallons); gas oil, 65,949,677 gallons (73,273,526 gallons) ; fuel oil, 95,062,147 gallons (48,135,845 gallons). THE SENCHENYDD DISASTER. The Coroner’s Inquest. At the inquest on the victims of the explosion at the Senghenydd Colliery, on Thursday, the 8th inst., the principal witness examined was Mr. Llewellyn Jacob, agent of the Welsh Navigation Collieries. As briefly reported last week, Mr. Jacob located the site of the explosion at the lamp station, thus agreeing with Mr. Edward Shaw, the manager. The Course of the Explosion. To substantiate his theory, Mr. Jacob described the condition of the workings after the explosion. Taking the portion of the road between the lamp station and the No. 1 crosscut, witness said that owing to the fire and bashings the complete examination of this had been rendered impossible by the fire. The engine over the road had been partly wrecked, the staging on which the engineman stood had been blown up to the top of the engine, and outwards towards the pit. On the crosscut between the intake and the return the two separation doors had been driven into the return. Then the explosion must have crossed the pit and blown out the separation doors in the east crosscut with considerable force. The lamp station on the east side showed that the flame had travelled back, because the lamp station was on fire, but the explosive force did not seem to have travelled much further on the east side. The only evidence was where they had been building a new arch, and the centres under this had been moved inwards. Between the lamp station and the return three separation doors were blown inwards towards the return. The explosion seemed to have travelled along the stable heading, because on the opposite side they found evidence of force having come over it. The timber right opposite the entrance was scarred with some old stone and chips of wood. In the Ladysmith return there was a smashed tool-box, which indicated that the force came away from the lamp station. A coat showed signs of burning, and they found pieces of a timberman’s saw driven into a piece of timber on the out-bye side. The doors on the first crosscut between the Ladysmith intake and the return were blown into the return a distance of something like 10 yards. Between the first crosscut and the return, stones were driven into the out-bye side, indicating that the force was travelling inwards. On reaching the second crosscut it was found that the door nearest to the return had been blown towards the intake, while the next door, the one nearest to the intake, was in an outward direction, towards the return. This showed that the force coming up the intake had met the force coming up the return. On Jenkins’ dip there were some very heavy falls. There was a tool-box on the mouth of the rubbish stall which was driven in-bye. In the Ladysmith intake there was some square timber about the engine blown in-bye, and here there was the body of a man partly blown on to the top of the engine. On Bull’s parting, a journey of empty trams was seen which had been forced inward around the back of a full journey of rubbish. Travelling along Lewis Morgan’s level some stones were found forced into a collar on the outer side, and just beyond this a fall for about 80 yards. The ground had risen about 2 ft. 9 in. On the first parting there was a tool-box smashed inwards. In Snailham’s dip, in the roadman’s cabin, a watch was found. Its glass was broken, and it had stopped at 8.12. On the Lancaster level was found an empty journey driven into the side. The remainder of the journey was standing some yards further in-bye driven inwards. Six outer trams were driven together and across the road, whilst the remaining eight were standing on their heads. There was only one part where the direction was against his theory, and that was where the arch had collapsed. He accounted for this by the fact that the explosion would find the roadway narrowing from 18 ft. wide and 10 ft. high to 8 ft. wide and 6ft. high. The force coming down the level would meet with that obstruction as it was going back. Just outside the Mafeking storage there was a journey of trams attached to a rope at the time of the accident. The outer tram had a stick in the bottom of it, and the door had been driven inward over the top of the stick, wedging it so tight that the bottom hinge had been broken. Referring to one of the doors, he said one of the hinges was blown 33 ft., and another 51 ft. in-bye. Above the door a beam was set in the masonry weighing between 500 lb. and 600 lb., and this beam had been driven inwards 16 yards. Mr. Jacob believed that the forces must have met at a point on the Mafeking level. He could not accept the theory that the force came down the Mafeking hard heading, as there were no chips of stone there. On the Mafeking hard heading a heavy fall took place, and some casks and timber were found driven in, and some irons on the drum were bent in. The Attitude of the Home Office. On the following day (Friday) Mr. Jacob continued his evidence. A diversion was caused by Mr. W. P. Nicholas, representing the Miners’ Federation of Great Britain, who asked if it was the intention of Dr. Atkinson, on behalf of the Home Office, to cross-examine the witness. In doing so he protested that the Home Office did not see fit in the case of the greatest disaster which had ever been in the coalfield, to be represented by counsel to cross-examine witnesses and assist in getting at the origin of the explo- sion, or to indicate what alternative theory. they were putting forward. The Coroner pointed out that he had no sort of control over the Home Office, but he had taken the precaution to have several inspectors of mines to give evidence, and would call them at a convenient time. Mr. Kenshole, on behalf of the colliery owners, said he associated himself with the protests made. Dr. Atkinson said he was acting under instructions in this matter. The evidence of Mr. Jacob was then resumed. Replying to Mr. Nicholas, he said that the lamp in the lamp station had been found on the table, but he could not agree that an important link in the chain of circumstances was missing. The woodwork was shattered in the lamp station, but the glass on the table was intact. He could not accept the suggestion that that was strange. Mr. Jacob thought the shaft acted as a safety valve, and the explosion passed up. He would not agree that it was desirable to prohibit signalling by electric apparatus on the main returns. Prosecutions by the Workmen. In the course of cross-examination, Mr. Brace argued that the Mines Act should be amended so that the workmen might be able to prosecute the management without the consent of the Home Office for alleged breaches of the Act, as the management had now the right to prosecute the workmen. The witness could see no objection to such a course. Mr. Thomas Richards, M.P., then cross-examined the witness. He could not find any evidence that there was a second explosion. Tests with Signalling Apparatus. Mr. Charles P. Sparks, M.I.C.E., M.I.E.E, consulting engineer, Moorgate-street, London, was the next witness. He said tests were made to see whether sparks would cause ignition at New Tredegar rescue station on January 1 last, at which Dr. Atkinson, Col. Pearson, Mr. Nelson, the Home Office adviser, Mr. Thos. Richards, M.P., Mr. Shaw and others were present. Firedamp was forwarded from Cymmer. The explosive mixture was arranged in a closed box and the bells hung up. The maximum conditions of working practised were arranged and many hundreds of signals given, but it was found impossible to fire the mixture. They then removed the cover from the bells, so that they could see them sparking the whole time, yet there was no ignition. The spark was not sufficient to fire the mixture. They began with nine volts, and increased it to 13) volts, thus increasing the pressure by 50 per cent. Another mixture was made of town gas and air, and with 13J volts the mixture fired instantaneously. The firedamp was nearly pure methane, but in the town gas there was a good deal of hydrogen, and that accounted for it being much more inflammable. Answering questions, witness said he would not consider the “ spark ”—the faint, feeble spark—they had seen on the wires as “ open sparking ” referred to in the regulations. He added that when the regulations were made there was no knowledge possessed by anyone, so far as he knew, that sparking by signal wires would be dangerous. Asked if he thought the colliery company had done what was required of them by the regulations pertaining to electric wires, witness replied in the negative. The Rival Theories. On Monday, Mr. Thomas Griffiths, of Cymmer, gave evidence. He expressed the view that the explosion occurred near the lamp station. Speaking of the possi- bility of gas having been driven by the fall, he observed that his lamp had been extinguished through gas going off by a fall 300 yards away. He had heard that the inspector had formulated a theory with regard to the origin of the accident on the Mafeking hard heading. But the forces, especially upon the Mafeking storage, were inconsistent with such a theory. Witness stated that, coming to the third door near the haulage engine on the Mafeking level, the force increased both in strength and velocity to such an extent that the door was broken to fragments. The force must have been terrific at that point. If the Mafeking theory was correct, witness would have expected the two doors to have been blown out in the same direction ; the fact that one was blown one way and one the other was consistent with the diversion of the forces in accordance with the witness’s theory. Witness thought that the greatest evidence of force was on the west side—the face side. Witness said it was a matter of impossibility to water sides and roof. The suggestion had been made that timber should be used all the way, but he did not think this was safe. Dust rested on the collars of the timber. Cogging was a satisfactory way of dealing with cavities, because it exposed them to the current of air. Witness had calculated the quantity of air likely to pass through the pipes of the pit, and the result showed 170 gallons a minute, or, taking an eight-hour shift, 15 gallons per lineal yard of roadway to be watered. The roads were still watered, and showed signs of regularity in watering. Witness said he did not wed himself absolutely to the lamp-room theory. His evidence was consistent with the origin being at any point between the No. 1 North and the lamp-room. Witness had not been able to get a bright