had sought a wage rise to compensate for the poor safety and been refused. They went on strike and were immediately sacked. Since the miners lived in tied cottages they were therefore evicted by force. The mine owners then brought in Irish Catholics to work the mine. Workings Most of the coal was worked using the Newcastle system, also known as "pillar and stall" or "stoop and room". A heading was driven into the coal and at intervals along it rooms were excavated, around wide. As the rooms got deeper another heading was driven from room to room to leave pillars (or stoops) about square behind. During this stage only around 30% of the coal was extracted. Eventually the whole district consisted of a grid pattern of passageways around stoops. The final stage in extraction was "stooping". The furthermost roof was supported by pit props and the stoops removed. Once a complete row of stoops had gone the props were removed from the furthest part which would collapse into the space ("goaf" or "gove") behind. During this process settlement and fracturing of the roof and seams above could occur, potentially releasing larger quantities of gas. The alternative method of working the coal was the longwall system. Two headers were driven forward to the far end of the district and an interconnecting passageway excavated. The passageway was supported by props and the long wall on the shaft side of the passage excavated. As this wall retreated the roof was propped and the furthermost props removed, allowing the overburden to collapse into the goaf. With longwall the same fracturing and gas release that stooping could cause was always present. The ell coal was mainly worked by stoop and room, with longwall in the southern part only. The main was exclusively worked by longwall and the splint (apart from a trial section) worked by stoop and room. Ventilation In collieries at that time air circulation was induced by a furnace at the base of the upcast pit. Hot air rising up the pit, as if up a chimney, drew the exhausted and contaminated air out of the galleries. Downcast pits let the fresh air in to replace it. The route the air took was carefully controlled by doors and partitions. At Blantyre pit, number 5 was the upcast shaft for pits 1, 2 and 3. About 5 tons of coal were burnt per