On Thursday 16 January 1862 the fore shift went on duty at 02:30. At 10:30 the same morning the back shift were taking over from the fore shift, so most men of both shifts were at the coal face. As the first eight men were ascending, the beam of the pumping engine snapped and fell down the shaft. Although much of the
brattice was destroyed, the first part seems to have deflected the beam away from the cage. Other debris fell on the cage, snapping two of the four support chains. Four of the eight men fell; the others managed to cling on. The beam came to rest jammed in the shaft and other falling debris created a blockage deep between the yard seam and the high main.
Rescue attempts One of the deputies, Matthew Chapman, had been on his way home when he heard the crash. Retracing his steps he had himself lowered on a rope and started to clear away some of the debris with an axe. Realising that the man was exhausted, having just come off shift, the
under-viewer Joseph Humble sent him home to rest whilst the main rescue effort was organised. The initial rescue attempt was carried out under the direction of Humble, Carr (owner and
viewer), G B Hunter (Cowpen & North Seaton), Hugh Taylor (Backworth) and
Matthias Dunn (HM Inspector of Mines). By midnight rescuers had reached the damaged cage and George Sharp Snr was brought up in a rope sling. However, he jammed against some overhanging timbers, came out of the sling and fell to his death. The rescuers (including the by then rested Chapman) then descended the pump staple and lowered a rope sling from the high main. William Shape and Ralph Robinson were brought up from the cage in this manner. Thomas Watson, a Primitive Methodist
local preacher, had earlier descended from the cage to the men who had fallen. He remained with them to pray and comfort them until they died. Watson likewise ascended in a sling and was therefore the last man out alive. With the pumps stopped, all knew that the low main would quickly flood. Those on the surface, therefore, assumed correctly that the men below would make their way via the staple up to the yard seam. Throughout the night men continued to work from ropes. By 9 am. Friday the rescuers had removed the debris in the shaft (mostly timber from the brattice) to within about from the furnace drift, and thought they could hear noises from the men in the yard seam. They were then relieved by sinkers from nearby pits.
William Coulson, the master sinker who had supervised the sinking of the shaft in 1845–46, was on a train passing through Hartley station on his way to another job. When passing through Newcastle that morning he had learnt of the accident; he sent a subordinate to see if assistance was needed. On offering his services, he was put in charge late on Friday afternoon, the previous committee yielding to his greater experience. There were occasional falls of rock from the sides of the shaft below the high main workings. By Saturday night, the rescuers were about above the furnace drift. At this depth the shaft crossed a 'trouble'; when rubbish was removed below this there were massive rock falls, with the shaft expanding to up to across in some directions. It became necessary to timber up the sides to secure them before attempting to go lower in the shaft; this took about twelve hours. From Sunday morning onwards, a small hole was excavated through the fallen stone towards the furnace drift. As the men worked through the blockage they were inconvenienced by fumes of carbon monoxide from the upcast furnace and from measures it had ignited. When a small penetration was finally made (3 a.m. Tuesday) there was a release of noxious gas ('carbonic oxide'
i.e. carbon monoxide) rendering some of the rescuers speechless; the entire working party had to be rescued and within half an hour the gas had risen to above the high main. To restart some ventilation a cloth brattice was rigged from the yard seam down to the work area. This was made from lengths of bratticing cloth held by various local collieries and was not complete until Thursday. On Wednesday morning, with the bratticing incomplete, George Emmerson (one of Coulson's sinkers sent to investigate if what remained of the pumps would collapse further if debris around them was removed) got three yards into the furnace drift before being forced back by the gas. He had seen an axe, saw and sawn timber, indicating that trapped miners had attempted to escape along that route; but the tools were rusty. Carr felt able to reply to a telegram sent from
Osborne House ("The
Queen is most anxious to hear that there are hopes of saving the poor people in the colliery, for whom her heart bleeds") that there were still faint hopes of getting at least some of the men out alive, but these hopes were soon dashed. At the pit-head standers-by had expressed unease at the slow progress of the rescue operations. Two pitmen in their number (William Adams of Cowpen and Robert Wilson of Backworth) were invited to go down the pit and report back to their colleagues on how things stood; exceeding their instructions, they managed to enter the yard seam and found dead men. Humble and a fellow-viewer (a Mr Hall from Trimdon) penetrated further and found all the miners dead, but on their return to the bank were severely affected by the gas. Others went down later but many became seriously affected by the gas: they reported (according to the 'Newcastle Journal') dead men in every direction, most near the shaft; most seemed to have died placidly: "The exploring parties have seen little boys in the arms of their fathers, and brothers sleeping dead in the arms of brothers". The dead pony was untouched; its corn bins had been emptied and some of the dead had corn in their pockets. Although the rescuers had thought they had heard signalling from the trapped men as late as Saturday night, the last entry in the notebook of the
back overman described a prayer meeting held at 1.45 on Friday afternoon.
Recovery The task was now recovery of bodies, and, the check-viewer told the waiters at the pit-head, it was no good throwing away the lives of living men to obtain the bodies of dead men: further entries into the yard seam were suspended until the canvas bratticing was completed, and the shaft properly timbered and cleared further to allow the yard seam to be accessed directly, rather than via the furnace drift. The following day, the
Journal reported ugly scenes at the pithead, with demands that the bodies be retrieved immediately; conversely, the workers in the shaft were becoming more reluctant to run the risk of the continuing rockfalls. On Friday, the rubbish in the shaft fell away to below the entrance to the yard seam, but rockfalls and releases of gas continued. By Saturday the works were complete and the sinkers and shaftmen withdrawn. The victims had been dead a week and so the bodies were "considerably swollen and disfigured" and the smell from them offensive. It had been intended to put them into coffins while they were still down the mine, and the medical profession thought it unwise to allow the coffins to lie in the victims' homes until burial. In the event, the corpses were raised to the pit head to be identified as far as possible by the tally-boy, sprinkled with
chloride of lime, shrouded, and coffined. In the end, however, as each body was coffined it was either sent home or, if unidentified, chalked "unknown" and sent to the Primitive Methodist chapel for later identification. The
Journal reporter described the consequent appearance of the village: All the blinds were drawn; but, looking in at the open doors, we saw coffins in every house. In most instances, they lay upon the large bed, so characteristic of the pitman's dwelling … Sometimes the bed would not contain all the coffins; and then they were disposed on chairs beside it. And so we passed up the row, and saw two, and three, and four coffins all in one little room, till, at last, coming to the end house, we were appalled to see a perfect pile of them…; and looking round, we were informed that seven dead bodies lay in the cottage. In every house women were sitting by the fire nursing their grief; and strong men, pale and dejected, were visibly suffering from the reaction of the excitement of the past week. The retrieval of bodies continued until four in the morning of Sunday; the yard seam was then checked thoroughly to ensure all bodies had been removed, and New Hartley and surrounding settlements canvassed to confirm that no body was missing. At one o'clock on the Sunday carts arrived at the cottages and most of the coffins were carried in procession to Earsdon Church. The graveyard was not large enough and more land was given by the
Duke of Northumberland; a large number of graves suddenly needed were dug by men from Seaton Delaval colliery. Fifty men were employed in digging the graves, and they did not complete their task until well after interments started (at about one thirty); dusk was falling as the last coffin was buried. A list was published of 'the workmen left alive that were employed at Hartley Colliery': there were only fifty-five. The loss of life was extreme, even by
Victorian era coal mining standards, and remains one of the worst mining accidents in England.
Causes An inquest was held on Tuesday 21 January 1862 on the five men killed directly by the beam fall, but this heard little evidence, the coroner expecting a "more particular inquiry, should some of the rest not be got out alive". The enginemen reported what they had seen and heard when the beam failed; one also told of an incident during maintenance about a month previously. The beam had been lifted by hydraulic jacks from its centre bearing to allow the bearing brasses to be replaced. During this operation, the hydraulics had failed, and the beam had fallen. However it had fallen only , back into its bearings; the witness did not think so small a drop would have damaged the beam; he had not seen any damage to the beam, and the engine had run well until the beam failure. It was also noted that there were casting defects visible at the fracture surface. As the coroner had foreseen, a second inquest was needed and was held 4–6 February 1862.
Sir George Grey, the
Home Secretary (to whom the Mining Inspectorate reported) sent down an expert ((John) Kenyon Blackwell) to assist the coroner. Blackwell was to make a separate report on technical issues and was to use the inquest as an opportunity to collect information for his own report. At the second inquest, a variety of experts and experienced men gave their opinions on the cause of the beam fracture. They differed over some details but were in general agreement that the 'spears' linking the engine beam to the pumps it was operating had failed in tension (some held that this had been triggered by a pump piston jamming; others held that the failure occurred simply because the spear was in poor condition). With the load on the beam removed, there had been an abnormally fast and large stroke and the beam had hit equipment on the 'in-house' (steam engine) side of the beam with great force; the shock loading causing
brittle failure of the
cast iron. John Short, the engine-wright, gave the basic information about the engine, the beam, and the pump spears. The beam had been made nearby by Messrs
Losh, Wilson and Bell of Walker. It had been assembled from three components. A central '
gudgeon' whose middle portion was hexagonal was threaded through a hexagonal hole in the central boss of two massive castings joined back-to-back with bolts, studs and spacers. Each casting had a thickness of at the central boss, and at the upper and lower edges with a web thickness of . The beam had an
effective span of ; its greatest height was at the central boss; it weighed over 40 tons. The spears ran as a single main dry spear of square Memel pine to just above the high main. A 'Y' then connected the main spear both to the wet spear of the second stage pump and to the square dry spear of the bottom pump. Coulson reported that the main spear had broken 12–14 feet below the bank; the bottom dry spear was broken at a 'spear plate' (junction piece) opposite the high main. From his examination, they had failed under tension (and therefore, he deduced, before the beam broke). John Hosking gave expert evidence on the pump beam. He pointed to weakness in the beam design and its installation. There was too much metal in the central boss and in ribs, whose net effect was to weaken the beam. The orientation of the hexagonal holes (apexes at dead top and dead bottom) had both weakened the beam and given points from which a fracture could start. The beam had been secured on the gudgeon by driving wedges between them; from the hammer marks on the wedges, this seemed to have been done with excessive force, which would have introduced undesirably high local stress. It would have been better ('modern practice') to machine the central boss holes and the middle portion of the 'gudgeon' circular, with better engineered
keying between beam and 'gudgeon'. An ironfounder considered the iron of good quality; its strength was demonstrated by the irregularity of the fracture surface, and its quality by the colour of the fracture surface when fresh. There was no undue contraction. Hosking did not think a pump piston had wedged, the bottom spear had broken under normal load: "The wood does not appear to me to have been of very good quality. It might have been at one time, but is not now." He dismissed as irrelevant two points which had attracted comment: • considerable voids ( x ) could be seen at the fracture surface close to the central boss; they were shrinkage voids, to be expected with so massive a casting unless special precautions were taken, and would not significantly affect the strength of the beam. • he did not think that the earlier drop had any connection with the subsequent failure: the beam had fallen only which he thought insufficient to initiate any fracture; the drop had occurred 33 days before the beam failed – he did not think a significantly damaged beam would have survived so long; the fracture surface after the beam failure had been uniformly bright, which ruled out any slow progressive failure or partial previous failure. Blackwell's report to Grey (written a week after the inquest) concurred with Hosking and drew attention to factors which Blackwell felt had made the accident more likely than for most pumping engines; • at Hartley both 'inhouse up' and 'inhouse down' strokes were driven by the engine, whilst in the usual
Cornish engine cycle for beam pumping engines, only the 'inhouse down' stroke was a power stroke, the return stroke being driven by the weight of the pump gear. On loss of load, therefore a Cornish engine would stall, whereas there was nothing to stop the Hartley engine over-speeding to its own destruction. • all three stages of pumping were carried out by
bucket pumps; to ensure the bottom stage could be mended if it failed and the mine flooded, it had to be a bucket pump, but the other stages should have been
plunger pumps to lessen the normal load on the beam • On bucket pumps heavy spears would add to the load on the pumping stroke; on plunger pumps heavy spears gave a quicker return stroke, and therefore there was always a tendency for bucket pumps to have less substantial spears. • Even with equally substantial spears bucket pumps were more liable to break their spears (and hence 'lose the load') than plunger pumps; either by deformation of the piston, or by obstruction of water flow into the pump, and it had been proved that the sump at the bottom of the shaft at Hartley had not been cleaned for a considerable time. ==Aftermath==