| Inspector Dickenson's Report, Continued. |
| ...The old bottom bed mines in this group comprise those which were worked by Messrs. Blackburne, Brodie, Chantler, Ellson, Hadfield, Neumann, and Reynolds and Digman. There is also near to this set of inundated mines, but said to be separated from them by a barrier of about 30 yards, another inundated mine, which was called Blackburne's New Mine, that became filled with brine from the rock-head. Up to the present time this latter reservoir has not been tapped, but the brine-pit which Messrs. Verdin are preparing could work it or the preceding reservoir. How far all three reservoirs may be separated from each other is open to doubt, and it is certainly supposed by some persons that they are connected at the rock-head. Other abandoned old rock-salt mines are - At Lawton ; one near to the Lawton old brine-shaft, both of which , it is said, were sunk in the year 1779 ; also another old rock-salt pit, on the opposite side of the brook, about a quarter of a mile lower down the valley. At Winsford, the National Salt Company's to the bottom bed of rock-salt at Wharton. In Ireland, at Duncrue, near Carickfergus, the Belfast Mining Company's first pair of old pits. The Inundation of Platt's Hill Rock-Salt Mine, has added another bottom bed mine to the Dunkirk set of inundated mines, from which brine is being pumped. I described in my 1873 report two perforations that had been made through the barrier which then separated Platt's Hill Mine from the Dunkirk old mines. One of these holes had been stanked or stopped by means of strong wooden uprights let into grooves cut 18 inches in depth into the roof and floor, with diagonal supports ; and the other, where the hole was small, was stanked, by screwing against it with a strong screw jack, an iron bell 17 inches in breadth, the face of rock-salt about the hole being turned quite smooth, and between the salt face and the bell there was placed india-rubber covered with canvas and red lead. Both of these stankings were in the upper part of the mine, called the roofing, which was about 6 feet in height, and they proved sufficient, with the exception of a little leakage at the wooden one, to keep the brine out. The mine being in my inspection district, and knowing that the barrier was thin, and that the separation was likely to be slowly dissolving by some of the brine pressing against it not being at times fully saturated, and knowing also that at one part of the mine there was the unusually long distance of 43 yards where the roof was without any pillar for support, the matter required attention for the safety of the workpersons lest they might be caught by an inundation. This was provided for as far as practicable. For some years I had gone into the matter with the owner and found that on the dip of the shafts there was standage room for 21,032 cubic yards of water, or brine, and that there was a raised roadway to the shafts, which seemed to admit of a reasonable chance of escape. The men were not in the mine when the inundation occurred, but if they had been, it is satisfactory to know that the provision for egress which was relied upon would have allowed time for their escape. A little before 6 o'clock on the morning of the 6th December 1880, before the men went down, the inundation came. The land slipped from underneath Peover Brook, and water poured in with an abundant supply from a new flash which is forming in Witton-cum-Twambrooks, with water from the Witton flashes and the Weaver Navigation also, which turned the current in the Weaver backwards which filled the mine and the adjoining old workings at a rapid rate. Besides the extensive old workings, Platt's Hill was a large mine, with excavations from 15 to 18 feet in height, the depth of the shafts being 321 feet. Having received notice of the inundation I visited the place the following morning with the view of ascertaining the particulars and whether the safety of persons in any of the adjoining mines might be affected. On my arrival I found the water up to 78 feet from the top of Platt's Hill shafts, being considerably above the rock-head and nearly level with the Weaver Navigation. Many acres of surface were still on the move, with large cracks or breaks going on, and water was bubbling up in levelling itself in the numerous ponds, and as air was being forced out under considerable pressure from the old excavations, bringing with it a smell like sewageor the long accumulated remains from powder smoke. Parts of Ashton's salt works and a large chimney had fallen into some of the chasms, and the road, and the brine pipes for conveying brine from the brine-pits to the salt-works were broken up. The occurrence was considered one of the most extensive and alarming that had ever occurred in the district. From water persons said, it appears that when the inundation was in full force, the large ponds surrounding the old fallen-in pits looked like so many boiling cauldrons with the water and air bursting up over the surface, and that on the banks there were a number of what were called mud volcanoes, the wet earth being thrown up seven or eight feet in height. Mr Foster, the engineer at the Cheshire Amalgamated Company's brine-pit, informed me that early in the morning of the inundation, as he was preparing to begin work, he heard the noise, and that the brine in his shaft, which had lately been below the top holes in the snore or blast pipe at the bottom of the pumps, rose to 63 feet from the top of the shaft, the depth of the shaft being similar to the depth at Platt's Hill. Mr John Thompson, the owner of Platt's Hill Mine, and one of his sons, pointed out to me that the principal sink or landslip, where the water had gone in, was over where the bell stanking had been made in the mine as described. Mr Moore, the foreman of Platt's Hill Mine, stated to me that about an hour and a half after the inundation commenced he went down one of the two shafts with a miner, and found wind blowing up the shaft so strongly that large lamps had to be sheltered in the bottom of the hoppet, and that on reaching the bottom of the shaft the water and brine had filled the lower part of the workings and was about one foot in depth at the shafts, and there was a roaring noise coming from the direction of the bell stopping, and that after waiting there for about 20 minutes or half an hour they came up again. Afterwards, at a little after 10 o'clock, being more than four hours after the inundation commenced, Mr. Moore went down again. Mr Arthur Anderson, jun., one of the principal engineers of the district, informed me that he went down on the latter occasion with Mr. Moore and that judging by the distance from the roof of the mine, the water had then risen to a depth of 7 feet at the shafts, and that as soon as the hoppet they were in touched the water it was surged away like a cork. As neither man nor beast was in the mine and no property could be saved, they came out, and by 5 o'clock in the afternoon the water was high up in the shafts. The inundation I found had not affected the Wincham or Marston rock-salt mines nor brine-pits, there being a barrier said to be at least 60 yards in width, between the Platt's Hill mine and the Wincham and Marston old and new mines, but at the neighbouring mines at Witton the water and brine rose higher than the tubing or cast iron cylinders in the shafts, and if coverings had not been hastily put on some of them would have been inundated. At Messrs. Thompson's, Witton Hall Mine, in Mill Street, the covering was kept on for a week or so, until the level of the water had lowered, and when it was removed the rush out of compressed air is said to have resembled steam from a boiler, although neither water nor brine had found an entrance below the coverings. At Messrs. Verdin's, Barons's Quay Mine, in Leicester Street, the water did not come until the third day after the landslip, but had they not taken the precaution to seal up the top of the cylinders in the shafts the mine would have been inundated. The water, according to Mr. Robert Verdin's account of it remained upon the covering for five or six weeks, but the moment it subsided they placed five or six more cylinders on the top of the other, which will prevent the water going down if there comes a recurrence of that sort. |
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