Part of the summary from the official Inquiry Report for “Blantyre Colliery Explosion” of 1877. Transcribed by myself word for word for the first time appearing online, this particular section, can be rather technical at times, but deservedly so, as it dealt with the important matter of ventilating the colliery. The information is in good detail, for those who care for that.
VENTILATION
“The ordinary ventilation of the splint coal consisted of about 50,000 cubic feet of air per minute, of which 26,000 went down No. 3 shaft and 24,000 down No 2. The air going down No 3 was split or divided into two currents, one ventilating the north and the other the south workings in that pit. These two currents united before entering No. 2 pit where they were again split into two portions. One of these splits, 10,000 feet, which was restricted by a regulator, aired a small extent of North workings on the dip of No 3 shaft, and then, after a short run, united with the return air from the ell and main coals (50,000 feet) and after mixing with that, passed through the furnace to the upcast shaft. “
“The other split passed through a long range of workings, which was the principal scene of the explosion. It was then joined with 10,000 feet of fresh air from No 2 shaft, with which it travelled through a portion of the rise workings of No 2 pit until it united with 14,000 feet, being the north return of No. 2 with which (after a mixing run for dilution), lest one split might be explosive) it passed through the furnace. The length of run of the portion of this split from No 3 shaft was altogether about 8,120 yards. Of this about 2,100 yards was in No 3 pit, counting only the shorter split there. It went to all the working faces of No 3 before beginning its work in No 2. In No 2 it passed numerous working faces, including the pillar work at the stooping, picking up gas as it went along.”
“The ventilating power consisted of a furnace of cube. It was in three parts, each being 4 feet wide with 8 feet firebars. One of these was kept in reserve and two worked night and day, including Sunday, about 5 tons of coal being burnt in each 24 hours. The arrangement was that the night cubeman should begin at 6pm and remain on duty until relieved by the day cubeman at 6am and for the day cubeman to make his fires up at 4pm and then leave the pit, there being usually no person in the pit between 4 and 6pm. Practically, however it appeared the the night cubeman made his fires up and left an hour or two before the arrival of the day cubeman. “
The principal stoppings, on which the air depended for being forced to make its circuits were made of brick and mortar. Some, as shown on the plan, were of wood, with overlapping joints. At one important point where the air had to be prevented from escaping into the waste amongst the formed stoops the stoppings were of wood, but where this air would naturally have come out the stoppings were of brick and mortar, with small holes in them for regulating the leakage of scalage of air to ventilate this waste. The practice in this colliery, it appears was to make the stoppings primarily of wood, and afterwards to replace them with brick and mortar. For some time prior to the explosion, consequent upon No 3 shaft being fitted with guides in the third compartment in order to begin working the ell coal, there had been no time to send brick and mortar down the shaft, which caused the building of some brick and mortar stoppings to be delayed. This , however, had apparently nothing to do with the explosion. Indeed, in steep mined, either a little leakage or scalage of air is indispensable at the innermost stoppings until the stoops or pillars have ceased discharging firedamp actively, or the stoppings must be built only just into the solid ground near the lower end of the opening, to prevent gas accumulating below them.
The air or trap doors were hung upon one pair of hinges and so fixed as to open against the air and fall to of themselves unless fastened back. At important points there were check doors, so that whilst one was open, the other should be shut. On two of three of the engine planes, where trains of hutches passed, and ropes went underneath the doors, a door boy, or trapper, was stationed to open and shut the doors. Where pony drivers passed with their trains, the doors had unusually a rope for pulling them open at one side. The driver walked by the side of or near to his pony, and having got his first hutch through the door, each succeeding hutch kept it open until the last one had passed, when the door fell to with a bang.
The working places or rooms had bratticing or temporary partitions for sending air to the faces. These were very numerous, and consequent upon each stoop not being completed or cut round before driving in advance and commencing others, the length of bratticing was extraordinary. In some of the places the bratticing was 60 yards, others 70,80 and even 90 yards in length. The principal split of air had to pass 63 bratticed places. The length of bratticing in No 3 pit was on the south side 511 yards and on the north side 748 yards. In No 2 pit it was from the junction of No 3 pit to the No 2 south level 726 yards and from the south level to the furnace 286 yards. There was thus a total length of 2,271 yards, or more than a mile and a quarter of temporary bratticing, without counting long lengths at the north side of No 2 pit. This bratticing was made of wood. The area or space behind it for air averaged about 25 square feet, and at the entrance to each place there was a tarpaulin screen to send air forward. The firemen and roadsmen fixed the bratticing, and if any got knocked down, it was the miner’s duty to leave the place and inform the first fireman or roads man that he could find.
Between the working faces and the shafts there were labyrinths of rooms surrounding the formed stoops. The length of roadway in these labyrinths, or wastes, amounted to many miles. These wastes were reputedly visited, so far as accessible, one a month or once in six weeks. Many of the places were fallen, and could not be inspected. Gas had been on one occasion found at a fallen part. Generally, no gas was found in them, the active discharge having ceased. Some wooden stoppings, which had been formerly used, were left in, but there was no defined system of coursing air throughout them. Leakage or scalage of air was allowed, but without any means, as far as the plan on the evidence showed, of preventing it going direct from the inlet to the outlet, without side places being ventilated.”