Reversing the ventilation
Friday 6th - Sunday 8th March
Those controlling the rescue operations were trying to do with seven men what was the work of more like forty. The seven men under ordinary conditions would not have made more than one descent in the day, and, it was clear that asking men to go back after an interval of say two or three hours was only justifiable by the exigencies of the circumstances under which we were working. The mine had been explored for a distance of 850 yards but the distance to the Jubilee Stables, which was the nearest point where men were believed, was 1,150 yards which would have meant exposing them to too great danger.
A consultation was held, and it was decided that it was futile to further explore the workings as things were, and the reversal of the air was decided upon.
Previously, when Mr. Johnstone arrived at the colliery late on the night of the disaster and heard from Messrs. Grazebrook, Waterhouse, Hughes and Charlton the only gentlemen then present, the condition of affairs at the seat of the fire, he had at once asked what steps have been taken to reverse the air? This had already been considered, but it was thought unwise to attempt it for several reasons.
One reason was the very strong natural ventilation which existed in the mine. The mine is deep and dry and warm, and the air courses are dipping slightly, practically right from the shaft inbye, and some portions of them are steep. The natural heat of the mine would tend to induce considerable ventilation, added to by the furnace existing at the bottom of the upcast shaft. Then there were the two firegrates erected in the return airways for the purpose of drying the air. Those firegrates would necessarily impart a considerable amount of heat to the strata along the return airways, and would very much increase the tendency of the ventilation in its normal direction.
Secondly there were concerns about the fan. The strain produced in the fan by attempting to reverse the natural ventilation and force the air in an opposite direction, while the original intakes were cool, and the returns warm, might have the effect of breaking down the fan. If that did occur while the men were 1,000, 1,200 or 1,500 yards inbye it meant almost inevitably the loss of every man in the mine.
The fan had been working there for about twenty year, doing good work, assisted, of course, by the furnace. Mr. Grazebrook had stated that the fan had undergone very thorough repair a few days previously and anew shaft had been put in it, and it had been put in real good order. There was considerable doubt in the minds of those controlling operations about the efficiency of the fan which was evidenced by the fact that Mr. Holland, the late Manager, had approached the Board of Directors with a view to putting in another fan about three years ago.
Mr. Johnstone had also suggested, when he first heard of the difficulty with the fan, the advisability of assisting the reversal of the current by forming a waterfall in the upcast shaft by damming the overflow of the pump and putting the whole of the water down the shaft. But he was told this had been considered by the management and the idea abandoned, as just before the accident the engine-wright had reported that two portions of the shaft lining were in need of repair, and a sudden cooling of the shaft would bring in the walling, and so close up the shaft bottom.
The method adopted of reversing the air was to connect the fan drift with the top of the downcast shaft by means of a trench and construct a brick arch way of about 60 yards in length, and covering over the top of that shaft so that the fan could exhaust from it, and uncovering the top of the No. 2 (upcast) shaft and so converting it into a downcast. The work might have been accomplished in 12 to 18 hours' less time, but for the fact that the brick walling of No. 1 shaft proved to be excessively hard and thick; blasting might have been resorted to at this point, but it was thought that this would occasion the existing erections to fall in.
The management and others fearing that the mine fan would not be capable of reversing the air, Mr. Garforth despatched a Sirocco fan from Altofts Colliery which was to be used at the experimental gallery recently erected there for carrying out the experiments with coal dust, but though put in place it was not found necessary to use it. The fan was brought by train to Hamstead. Had this fan not been available at Hamstead then it is unlikely they would have allowed men to enter into the workings with the existing fan, because if the existing fan had broken down it would have meant certain death for those in the mine.
Constructing the trench to connect the fan drift with the downcast shaft
Next - Clearing the mine
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