THE INSPECTION
HAPTON VALLEY
Burnley, Lancashire. 22nd March 1962

In the course of the investigation two hessian sacks were found each containing the same type of Eq.S explosive in the cartridge form. One near the intake gate ripping contained 12 pounds on the other near the return gate ripping 56 pounds. Although the first 14 yards of the face from the intake gate stable 10 shotholes had been drilled in the bottom of the coal, Nine of these had been charged and stemmed and a single shot exploder with connected cable was lying between the ninth and tenth holes.

In the return gate stable seven shotholes had been drilled and six of them charged and stemmed. The charged shotholes were disposed in two groups, two near the ribside and four to the left side of the stable. In the short length between the two groups there was a heap of broken coal lying against the face. It was clear from the evidence in the roof and face that at least two shots had been fired in the vicinity. Of the group of four shotholes the one immediately next to the broken coal and about 12 feet from the face buttock invited particular attention. It was observed that the coal on the loose side of this hole was fractured by innumerable fine cracks. When this coal was removed by hand a plug or stemming at the front of the hole and three cartridges of Eq.S explosive were revealed. The latter were impacted together as through they had been subjected to pressure from the back of the hole, and the inner end of the last cartridge was covered by a coating of coal dust 1/8 " thick. The shothole was subsequently found to extend 12 inches beyond the last cartridge but this section was empty. A primer cartridge was not found and there was no evidence to suggest that the shot had blown out laterally. Two detonator wires were found in the hole one reached only as far as the stemming but the other extended to the inner end of the recovered part of the charge. Nothing unusual was observed in the condition of the remaining five charged holes and they were subsequently fired without incident under the supervision of H.M. Inspectors.

A shotfiring cable without detonator leads attached extended from the face side of the conveyer over a roof bar under the return gate ripping on to the ripping debris where the remainder was tied in a hank with one of the leads connected to a single shot exploder. A shotfiring exploder key was later found in the clothing of Halstead, the shotfirer whose body was recovered from nearby. A case subsequently found to contain 31 detonators was also found in Halsted's clothing. Some of these with others were taken from the colliery magazine 25 in all were sent to the Armament Research and Development Establishment, Woolwich for X-ray examination and test. They were found to be in normal in all respects.

Explosive from the pit and from the colliery magazine when tested for behaviour and composition proved to be normal. Tests for sensitivity to initiation of detonation on some of the explosive referred to in paragraph 51 showed that it had not deteriorated.

The five safety lamps and 53 electric cap lamps (some incomplete) recovered from the district were sent for test. The flame lamps and 28 of the cap lamps were found to be in approved condition securely locked and in working order. The remainder of the electric cap lamps had sustained some damage but this was considered to have been caused by the explosion.

Smoking materials were not found either during the underground investigation or when the effects of the victims were examined on the surface. No combustible material was found. No electrical defect was found. All signalling and exploders were found to be in good condition. The apparatus was examined to look for frictional heat and all was found functional. The seams included pyrites nodules known locally as 'bobbers' and ignitions of firedamp had been known at the colliery attributed to cutter picks striking them. Because of smears left by aluminium alloys left with rusty steel a thermite reaction could arise. A fire hose nozzle was tested and found that it could leave aluminium smears but there was no indication that it had done so. In the length of the return gate ripping there were 18 metal foils from the wrappings used for confectionery and chewing tobacco. When pieces of the specimens were submitted to glancing blows with rusty steel in a firedamp atmosphere ignition was obtained in all but two specimens. These foil wrappings which are generally of aluminium usually have paper backing sometimes waxed where this backing was retained ignition could not be obtained.

The two specimens which had signs of fusion when picked up 300 yards from the return gate ripping. The signs of fusion were very similar to the signs on the pieces of aluminium foil which had given incendive flashes when tested. The state of the roof was the same before and after the explosion. The roof breaks observed at the face by the afternoon and night deputies were not accompanied by marked displacement and were not unusual. The deputies described the wastes as behaving normally. The small cavities in the gates were attributed to the force of the explosion.