On the 19th day of September, 1921, at 9·25 a.m., a violent explosion occurred in the underground workings of Mount Mulligan Mine, killing seventy-three men outright, and so badly injuring two others that they succumbed shortly afterwards.
That an explosion of coal dust originated at the face of No. 11 gateway, Fitzpatrick's machine wall, south side, No. 2 seam, and travelled the working faces and roads of the mine and passed out of the entrance of both intake and return tunnels.
Three possible sources of origination have been suggested by the evidence.
Firstly, the discovery of the top half of an acetylene hand lamp, which was made in two sections, the bottom being made to clamp to the top, created an inference that the contents had exploded in the lamp and ignited the coal dust. An examination of the parts found showed no damage. The rubber washer between the two parts was adhering to the top part of the lamp, and had not been scorched. In view of the fact that more tangible evidence of other sources of ignition are available in this place, and that this theory was set up tentatively, we have discarded it.
The theory set up by Mr. J. T. Watson, supported by Mr. James Harris, that the charge had been exploded in contact with an open light in Morgan's hand when he was in the act of carrying it to charge a hole, is discussed at length under the heading of "Consideration of Evidence." As the weight of evidence is against this theory, and the evidence advanced in its support conflicts with other evidence, and takes no account of certain singular results observed in that place by witnesses, we find that this theory is untenable.
Having considered from every point of view the several theories advanced, including the possibility of an ignition of methane or other inflammable gas, having made minute examinations of mine workings, and carefully investigated the depositions of witnesses, we are unanimously agreed.
The cause of ignition was the firing of an explosive, either accidently or otherwise, on the top of a large block of fallen machine-cut coal, such explosive not having been placed in a shot hole.
It is difficult to understand how explosives, being used in the ordinary way, could be fired in this spot. Alternately the conclusion that obtrudes itself is that a plaster shot was placed on this block of coal –to break it, so as to facilitate handling, and it exploded prematurely, either because of defect in the fuse or from some other cause, such as a fall of roof stone.
Recommendations
SEPARATE COLLIERIES ACT.
1. The passing into law of an Act for collieries, separate and distinct from "The Mines Regulation Act of 1910," with a re-enactment of all approved sections of the said Act.
INSPECTORS.
2. The administration of the said new Act to be under the supervision and direction of competent colliery men.
The appointment of Inspectors to be made from men who hold colliery manager's certificates' of competency.'
Inspectors to be equipped with all necessary instruments for inspection purposes, including a lamp capable of detecting i per cent. of methane.
Inspections to be made at intervals not exceeding three months, and to include an examination of the returns and other parts of the mine for
methane, and
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the examination of roads, roof, and sides for dust;
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the state of the ventilation,
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the use of explosives in the mine,
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timbering, and
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mine conditions generally.
Records of all inspections to be made and returned to head office at intervals not exceeding one month.
RECORD BOOKS.
3. Revision of the Record Books, with the view of providing space for reports by more than one Deputy.
EXPLOSIVES.
4. Rigorous' administration of existing regulations regarding the use of explosives in collieries.
The use of only permitted explosives in all mines that are not naturally damp and free from inflammable gas, in substitution of Rule 19 of 1st August, 1912, regarding prohibited explosives. Where permitted explosives are required to be used, every shot hole shall be charged and stemmed by or under the supervision of a district shotfirer.
SAFETY LAMPS.
5. In addition to clauses (a) .and (b) of Rule 3, Division III., Part III. of "General Rules applicable to Collieries only," the insertion of a clause, as follows, namely:
In every case where, by reason of dry and dusty conditions obtaining in the mine, danger is apprehended by the Inspector, he shall have power to order the use of safety lamps or approved electric lamps throughout the mine or any part thereof.
STONE DUSTING.
6. We append copy of the British Stone-dusting Regulations for inclusion in the Queensland Act, in lieu of stone-dusting regulations contained therein :-
SPECIAL RULES.
7. We, recommend that a committee be appointed to revise the Special Rules, with a view to making better provision for the more effective control of individual collieries.
RESCUE STATIONS.
8. That rescue stations be established in all districts.
REVERSAL OF AIR CURRENT.
9. We recommend that, where new fans are installed, provision shall be made for the reversal of the air current.
SHOTFIRING..,