STORY OF THE EXPLOSION AND RECOVERY OPERATIONS

The explosion occurred at 3:26 p. m., March 25, 1947. The assistant mine superintendent stated that he was standing in the surface power plant when the fuse in the fan power circuit on the switchboard blew out, and that was the first evidence he had that there was something wrong inside.

The assistant superintendent immediately called the home of Driscoll O. Scanlon, the State mine inspector of the district, and the clerk in the mine office was instructed to call the superintendent of the State mine rescue station at Belleville, Ill. Before proceeding to the Centralia No. 5 mine, Mr. Scanlon left instructions to telephone to the director of the Illinois Department of Mines and Minerals at Springfield, Ill., to send all of the State mine rescue teams to the Centralia No. 5 mine as soon as possible.

The district office of the Federal Bureau of Mines at Vincennes, Ind., first learned of the explosion when the clerk at the mine office called the Bureau office about 5 p. m. Mr. C. A. Herbert, supervising engineer of district E, immediately ordered four Bureau men to the scene with the mine-rescue truck; these men arrived at the mine at 8 p. m. Mr. Herbert then ordered additional Federal· coal-mine inspectors to the scene, contacting them by telephone. They started arriving at the mine at 7:30 p. m. and continued arriving throughout the night and the following day. Thirteen Bureau of Mines employees were present and participated actively in the rescue and recovery operations. The names of the Bureau personnel are as follows: W. A. Gallagher, F. J. Smith, Frank Perz, W. W. Kessler, T. C. Higgins, J. S. Malesky, J. E. Stanton, H. C. Brumbaugh, Frank Kolisek, G. W. Colbert, W. R. Chick, M. V. Hansen, and Roy Capps. Thirteen members of the State mine-inspection department were present and participated in the rescue and recovery operations. The names and titles of these men are as follows: Robert M. Medill, director; Robert Weir, assistant director; John McMillan and Elmer Edmonds, inspectors at large; James Sneddon, safety engineer; George Hall, Frank Stank, R. R. Schiber, Fred Lippert, John Golden, J. R. Wilson, Ray McCluskey, and Driscoll Scanlon, mine inspectors. Seven State mine-rescue-station superintendents and rescue teams and one minerescue team from the Bell & Zoller Coal & Mining Co. were also present and participated in the work.

Immediately after H. C. Niermann, the assistant superintendent, had been advised that there was considerable smoke and dust at the shaft bottom, he assembled a permissible flame safety lamp and procured a permissible electric cap lamp and entered the mine. The cager was the only person at the shaft bottom when he arrived. He then proceeded to the fan which is located underground 1,200 feet south of the hoisting shaft. When he arrived at the fan, he found it operating properly, and he then met the mine manager and three other employees there. The mine manager advised Mr. Niermann that the situation looked bad. After a short discussion with the mine manager as to the procedure to be followed to try and rescue the workmen, Niermann proceeded to make tests in the main return airway outby the fan with a permissible flame safety lamp to ascertain whether or not there was any methane present in the atmosphere. No methane was detected and relatively little smoke or dust was present at that time. About this time, several men arrived from the shaft bottom with a locomotive and they were instructed to go into the main south entry and pick up two men that had preceded them into this entry; however, they were instructed to return to the shaft bottom if they felt any effects of afterdamp. The motor crew traveled only a short distance into the main south when they found one of the men in a dazed condition, due to the effects of afterdamp. He was brought to the surface where he recovered, but the other man was further inside, and his body was not found until the last day of recovery operations. At this time the night foreman and several other men arrived at the scene. Niermann received a telephone call from someone at 13 north 1 west requesting help for several men that were at the 13 and 14 north junction. He instructed the night foreman and the men that were with him to proceed to 13 north in the intake air, but not to go beyond 13 north. After he had issued these instructions he returned to the surface.

Upon Niermann's return to the surface at 4: 40 p. m., he found that Driscoll Scanlon, State mine inspector, had arrived at the time. Scanlon immediately ordered the electric power to be cut off from the mine. He then proceeded to the mine office to ascertain if the officials of the State department of mines and minerals and the supervising engineer of the Bureau of Mines had been notified of the disaster. He then went into the mine with Niermann. While passing the motor barn near the shaft bottom, the telephone rang; answering the tele

phone, he found that the call was made by one of the four men who came out of the 14 north entry alive after the explosion, and he instructed the survivors to stay at 13 north until he returned to the surface and obtained electric cap lamps. Upon his arrival on the surface at 7: 45 p. m., he found that the DuQuoin rescue team and James Sneddon, State safety engineer, had arrived. Scanlon and Sneddon entered the mine with the rescue team at 8 p. m., and proceeded to 13 north 1 west and brought the survivors to the surface on stretchers. While rescuing the 4 survivors at 13 north, 16 bodies were found along the 1 west haulage road at 13 north.

The intake air enters the 1 west haulage entry through an overcast 1,200 feet inby the shaft bottom, and the return air passes under the main south overcast, which places the haulage road between the shaft bottom and the 1 west on return air. As a result, the return airway had to be closed with a temporary stopping and the doors at the entrance to 1 west had to be opened to short-circuit the ventilating current and place the roadway between the shaft bottom and the 1 west entry on fresh air. This procedure had to be followed each time rescue teams changed.

Starting with the second crew which entered the mine at midnight, March 26, several of the Bureau men accompanied each crew and assisted with the direction of the recovery operations. Each rescue crew consisted of 2 mine-rescue teams and from 30 to 40 fresh-air men, as well as several State mine inspectors. The second rescue crew advanced to 15, 16, and 17 north abandoned roompanel entries off 1 west, and found the seals destroyed and carbon monoxide emanating from the abandoned area. This rescue crew returned to the surface and was relieved by another crew.

Due to the violence of the explosion, all stoppings and doors inby 15 north 1 west and the stoppings between 20 and 21 north off 4 west were destroyed. As a result, recovery work was delayed considerably because building material had to be obtained and transported from the surface into the mine, and stoppings had to be built to provide ventilation for the recovery crews to advance. Delays were also incurred because of the amounts of carbon monoxide encountered, which had to be cleared before exploration could be continued.

The rescue crews were organized in four shifts, and were under the direction of Robert M. Medill, director of the Illinois Department of Mines and Minerals. Recovery work was started at 13 north 1 west and was continued on through 18, 19, 20, and 21 north room entries and the 1 and 2 west main entries. The recovery work through this area was retarded because of the effects of the violence of the explosion. Recovery work in the 20, 21, and 22 north and 23 and 24 south room entries off 4 west progressed rapidly because of little violence.

The last body was recovered in 20 north off 4 west at 5:30 a. m., March 30. Immediately after the last body had been recovered, several crews of men reentered the mine to restore ventilation and to direct the air current in its proper course by removing temporary stoppings from the mouth of room entries and by building additional stoppings where they were required. This work was completed at 6 a. m., March 30. The mine was closed against the entrance of persons for 2 days to permit afterdamp to clear up in the return. The working faces and haulageways were examined by certified officials on Wednesday, April 2, and the mine was found to be in a safe condition for the various investigating committees to proceed. The recovery operations were officially ended at 9 a. m., April 2, 1947.

INVESTIGATION OF CAUSE OF EXPLOSION

An investigation to determine the cause of the explosion was made by the United States Bureau of Mines on April 2, 3, and 4, 1947. Investigators for the Bureau of Mines were Federal Coal-Mine Inspectors M. J. Ankeny, W. A. Gallagher, F. J. Smith, and Frank Perz, and Mining-Explosives Engineer J. S. Malesky.

Investigations of the disaster were also made by a Fact Finding Commission appointed by the Governor of Illinois, by the Iillinois State Mining Board, by a committee of the Illinois State Legislature, by the Coroner of Washington County, Ill., and by a committee of the United States Senate. No decision as to the cause and origin of this explosion had been released by any of these investigating groups at the time this report was completed.

DETAIL OF EVIDENCE

The map of the mine, appendix A, shows the underground abandoned and active workings, the locations of the shafts, the location of the fan, and the course

of the ventilating current previous to the explosion. This map also shows the probable point of origin of the explosion, the approximate area traversed by flame and the approximate area affected by violence. The map of the explosion area, appendix B, shows on a larger scale the course of the ventilating current previous to the explosion, the probable point of origin, the approximate area traversed by flame, and the approximate area affected by violence. In addition, this map shows the location of bodies of the victims of the disaster, the direction of major forces, the locations where dust and air samples were taken during the investigation, together with reference numbers thereto, and the points on the entries where the rock-dust zones terminated as of the day of the explosion.

METHANE AS A FACTOR IN THE EXPLOSION

Very little methane was liberated in the mine during normal operations previous to the explosion. At the time of the last Federal inspection, the mine was liberating a calculated quantity of approximately 64,000 cubic feet of methane in 24 hours. Table No. II contains the analytical results of air samples collected during the investigation. It will be observed that the methane content of the face samples ranged from 0.04 to 0.09 percent and two samples in the return air current contained 0.07 and 0.06 percent methane. The face samples were collected at a time when the ventilation had been only partially restored and there was no perceptible movement of air at the faces. An air sample collected at the face of 1 west, where the explosion is believed to have originated, contained 0.09 percent. Although tests were made frequently in the returns and at the face of working places during recovery operations by shift loaders who used flame safety lamps, traces of methane were not found. These facts lead to the conclusion that methane was not involved to any appreciable extent in this explosion.

TABLE II.-Air analysis report

[Mine: No. 5. Company: Centralia Coal Co. Collected: Apr. 1, 2, and 3, 1947]

Four of the six working sections of the mine were affected by the flame and violence of the explosion. The remaining two sections were affected only by the afterdamp resulting from the combustion of coal dust. Forces were extremely violent in some portions of the explosion area, while in others the velocity of the explosion was so slow that little evidence to indicate the direction of forces could be observed. The direction of forces was determined wherever possible by the movement of material, such as timbers, shattered remains of wooden stoppings, cars and other equipment, debris, and by the bending of trolley wire hangers. From evidence of this nature, it was determined that the explosion probably originated at the face of 1 west and spread north and south through the first openings to the right and left. The forces in 20, 21, and 22 north 4 west were generally strong in the direction of 4 west throughout the entire

length of these entries, except the portion of these entries in the active working section near 1 west where the evidence of forces was not pronounced in any direction. The forces evidently traveled across and through the rooms off 21 north 1 west and there was evidence of strong forces toward the faces of 20 and 21 north. Evidence indicated that the explosion traveled outby on 1 and 2 west between 19 and 20 north and also in three of the air course rooms between 19 north and 20 north. While there was much evidence of intense heat and flame in the rooms off 18 and 19 north, there was little evidence of force in any general direction in these rooms. The forces, however, were definitely and strongly inby in 18 north and 19 north entries. Strong forces from 1 and 2 west entered 18 and 19 north 4 west and traveled toward 4 west for a distance of approximately 800 feet. Forces in 1 and 2 west were definitely outby between 18 north and a point about 200 feet inby 14 north where they died out completely.

FLAME

The area traversed by the flame of the explosion was determined by a careful examination of abandoned and active workings within the explosion area. In this examination, evidence of flame was indicated by deposits of coked particles on mine surfaces and timbers, bits of burned paper, burned explosives, and cardboard explosives boxes, charred or burned sight strings, and charred or burned splinters on numerous timbers left standing throughout the explosion area.

Flame extended from the face of 1 west and the workings adjacent thereto to a point outby on 1 and 2 west approximately 800 feet from the faces of 1 and 2 west. Flame was present in 20, 21, and 22 north entries off 4 west, extending from 2 west a distance of approximately 800 feet toward 4 west on these entries. The active rooms off 20 and 22 north 4 west were also filled with flame during the explosion. Flame was present throughout 20 and 21 north 1 west and the active and abandoned rooms connected thereto. Flame traversed three of the air course rooms between 19 and 20 north 1 west, but failed to reach 19 north at the points where these rooms connected to 19 north. Flame traveled through the crosscuts in the rooms off 19 north and came out on 19 north entry through Nos. 17, 18, 19, and 20 rooms, crossed over to 18 north through the last two crosscuts, entered the rooms off 18 north through Nos. 17, 18, 19, and 20 rooms and traversed the active rooms off 18 north.

Special attention is invited to the fact that flame traveled through the crosscuts of all of the rooms off 19 north and a number of rooms off 18 north and failed to reach 18 and 19 north entries, except in the areas near the last three crosscuts.

FACTORS THAT PREVENTED THE SPREAD OF THE EXPLOSION

The explosion was localized and confined to four working sections of the mine; however, the two remaining sections into which the explosion failed to propagate were affected by afterdamp. The explosion failed to propagate further in every instance when it reached or as it approached the end of the rock-dusted zones on the entries. While the explosion traveled through all of the active rooms and some of the abandoned rooms in each section, none of which had been treated with rock dust, it failed to propagate through the old workings to any great extent because many of these were partially caved and in some instances filled with incombustible roof rash that had been transported there from adjacent entries by means of shuttle cars. While some of the back entries were not rockdusted, they were generally fallen in and the dust in them was largely covered by incombustible rock. A factor that retarded the development of high velocities as the explosion traveled outby was the existence of large areas of open abandoned workings which provided space for the relief of pressure. Unquestionably, the presence of rock dust in entries, even though somewhat deficient in quantity, was the most important factor in preventing the spread of this explosion throughout the mine and to the shaft bottom.

ACTIVITIES IN THE WORKING SECTIONS AT THE TIME OF THE EXPLOSION

A section of this report entitled "Explosives and Blasting" under the heading of "General information" describes in detail the blasting practices at this mine. It was established previously in this report that the explosion occurred at approximately 3:26 p. m. The official quitting time for the shift was 3:30 p. m. At the moment of the explosion, all face operations had ceased, except the igniting of shots which had been charged in the boreholes at various times during the shift.

Nearly all electric equipment in the immediate explosion area had been withdrawn from the faces and parked. It was definitely determined that no face electric equipment was in operation at the time of the explosion. It is, therefore, believed that the only possible ignition sources present at the faces at the time of the explosion were the open lights of the shot firers and a few others, and the detonation of explosives. Most of the men comprising the working shift were at the man-trip stations on the entries where the man-trips were already made up and waiting for the shot firers to complete the ignition of shots, so that the shot firers could ride to the bottom of the shaft with the man-trips, all of which was customary practice.

To support the conclusion that the explosion originated at the face of 1 west entry, the condition of the working sections in the mine is discussed in detail. 13 and 14 north section, 1 west

This section was the first set of workings ventilated by the intake air current and it was not directly affected by the flame and violence of the explosion. The man-trip was in process of being loaded in 13 north when the explosion occurred. Evidently all of the working shift in this section, except a machine man, a driller, a trackman, and a trip rider, walked down 13 north entry after the explosion and encountered afterdamp at the intersection of 13 north 1 west where they were all killed. Sixteen bodies were subsequently found at this point by rescue crews. The machine man, driller, trackman, and trip rider followed these men down 13 north entry sometime later and after finding the bodies of their comrades at 1 west, they contacted the assistant mine superintendent at the shaft bottom by telephone. Subsequently, these men were met by rescue parties. All four of them survived the explosion and it is believed that their 16 fellow workmen would also have survived if they had remained in the 13 and 14 north working section or if they had been equipped with and had used miner's self-rescuers. 13 and 14 north section, 1 west

Two crews of men were working in this section; one crew worked in room Nos. 19, 20, 21, and 22 off the 23 and 24 south entries, and the other crew worked in a group of rooms inby and the entries. Blasting operations had been completed in this section and the men had boarded the man-trips. The explosion must have occurred before the trips started toward the bottom of the shaft. The concussion from the explosion apparently warned the men that something of a serious nature had occurred in some other part of the mine, and they left the man-trips and started to walk toward the 4 west haulage road. Pieces of cardboard and wood that the men used to sit on in the steel cars, and their lunch pails were still in the cars, indicating that they abandoned the cars hurriedly. The outby group of 13 men was found on 23 south about 200 feet inby 4 west and about 700 feet outby the man-trip. The 14 men who had worked inby the farthest apparently tried to find their way to 22 south entry through one of the rooms which had been connected between 22 and 23 south entries. This group of men was found at the face of room 8 off 23 south, and notes indicating the time of day were found chalked on pieces of slate at the face of No. 11 room. Various notes left by these men indicated that some of them were alive but weakening fast at 7 p. m. Rooms Nos. 6 and 15 off the 23 south were connected with rooms driven from 22 south, but it is extremely doubtful that these men could have saved themselves by traveling that way, as they would eventually have to come onto the full return from the devastated areas. They could however, have retreated to the innermost point of the section and erected barricades. The doors and stoppings that were damaged by the explosion on the outby end of this section permitted the poisonous air to be short-circuited away from this isolated part of the mine.

The consensus of opinion of the men engaged in directing the recovery work was that these 27 men might have saved themselves if they had knowledge of barricading.

18 and 19 north section, 1 west

Room 13, 19 north: Fresh cut at face.

Room 14, 19 north Face of room and crosscut cleaned up. Mining machine back from face, controller off, nips off.

Room 15, 19 north: Cleaned up.

Room 16, 19 north: Cleaned up. Loaded car at face.

Room 17, 19 north: Cleaned up.

Room 18, 19 north: Cleaned up.

Room 19, 19 north: Cleaned up. Loaded car at face.

Room 20, 19 north: Cleaned up.