Mr. Roy Adams, general superintendent, immediately called the Illinois State Department of Mines and Minerals and the superintendents of the Benton and Herrin mine rescue stations, who were asked to send their rescue teams to the Old Ben No. 8 mine at West Frankfort as soon as possible.

The district office of the Federal Bureau of Mines at Vincennes, Ind., was first notified by Mr. H. C. Brumbaugh, Federal coal-mine inspector, who arrived at the Old Ben No. 8 mine at 1:45 p. m. to see Mr. Roy Adams on business. Upon his arrival at the mine, he was informed by Mr. Adams that there was a fire in the 13 east section off main south and that a number of men might be trapped. Mr. Brumbaugh immediately notified Mr. C. A. Herbert, supervising engineer, district E, by telephone at about 2 p. m. Mr. Herbert then directed several other Bureau men to go to the mine. The names of the Bureau personnel who rendered assistance during the rescue and recovery work are as follows: W. A. Gallagher, W. R. Chick, H. C. Brumbaugh, T. C. Higgins, James A. McCune, G. W. Colbert, and Roy Capps. Seven 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: Harold M. Walker, director; Robert Weir, assistant director; Elmer Edmonds, inspector-at-large; James Sneddon, safety engineer; and J. R. Wilson, Roy McCluskey, and John Golden, mine inspectors. Two State mine rescue station superintendents and rescue teams were also present and participated in the work.

Mr. Howard Lewis, underground superintendent, and John E. Jones, safety engineer, for the Old Ben Coal Corp. were notified immediately of the trouble at the mine. Upon Mr. Lewis' arrival, he immediately entered the mine and proceeded to the 13 east where he contacted the mine manager, who informed him that it was an explosion that had occurred instead of a mine fire. Mr. Lewis, Mr. Bowker, mine manager, and several other men entered the 13 east. When they reached the affected area, they found four men in a burned and dazed condition and one man dead from the effects of the explosion. These men were removed to the surface promptly. Upon the arrival of Mr. J. E. Jones and State Mine Inspector Elmer Edmonds, which was about 2:15 p. m., these two men, H. C. Brumbaugh, Federal coal-mine inspector, and Ernest Green, assistant general superintendent, immediately entered the mine. About halfway between the main shaft bottom and 13 east they passed the trip in which the four injured and one dead man were being conveyed to the shaft bottom. Upon their arrival at the 13 east which, they were met by the mine manager, Mr. Howard Lewis, superintendent, and several other mine employees. They entered 13 east entry which is the return air course of the 13 and 14 east section and proceeded to a crosscut outby 5 south where the door had been blown out. At this point they entered the 14 east entry which was the intake air course for this section and proceeded to restore the ventilation and begin the recovery work. Canvas bratfices were erected in the crosscuts where the concrete-block stoppings and wooden doors had been demolished by the force of the explosion. Work was continued inward on the intake air course entry. Six bodies were found in a crosscut about 60 feet above the 8 south room-panel entry off 13 east on the intake side of this section. The body of the face boss was found in the last place on the return air side in the place where the loading machine was broken down, and his safety lamp was found in the vicinity of old 7 north approximately 300 feet from his body, as shown on map, appendix B. Mr. W. R. Chick, Federal coal-mine inspector, arrived at the mine about 3:30 p. m. He immediately entered and joined the rescue party at the 8 south off 14 east main south. Other Federal coal-mine inspectors, State officials, and mine rescue teams arrived later and assisted in the recovery work which was completed at 12:30 a. m., July 25, 1947. The last body was found at 11:30 p. m., July 24, 1947. After the last body had been removed, four Federal coal-mine inspectors, who had been assisting in the recovery work, remained in the mine and immediately started an investigation to secure data pertinent to the explosion. After all the bodies were recovered, the company officials, State officials, and the Federal inspectors discussed the removal of the equipment because of the squeezing and falling of rock in the affected area. It was decided to remove the equipment, and this work was completed by 6 a. m., July 25, 1947.

On the morning of July 25, 1947, H. C. Brumbaugh and W. R. Chick, Federal inspectors, entered the mine and proceeded to make a sketch of the affected area. After the sketch was made, they decided to explore as much of the workedout area as possible above the working section and were accompanied by several of the company officials of the Old Ben Coal Corp. Two dust samples were collected inby the last working place on 13 east parallel entry and a coke sample

from a prop about 150 feet inby 10 south on 14 east parallel entry. At 9 and 10 south and for a distance of 200 feet inby, soot streamers were observed hanging from the roof, and deposits of coke and ash were observed on the floor. Further exploration of this area was considered to be too hazardous due to bad roof, smoke, and fumes.

DETAIL OF EVIDENCE

The map of the 13 and 14 east section of the mine, appendix A, shows the underground abandoned and active workings and the course of the ventilating current previous to the explosion. The sketch of the explosion area, appendix B, shows on a larger scale the ventilating current previous to the explosion, and probable points of origin, the approximate area traversed by flame, and the approximate area affected by violence. In addition, this sketch shows the locations of bodies of the victims of the disaster, the direction of major forces, and the locations where dust and air samples were collected within the explosion area during the investigation.

METHANE AS A FACTOR IN THE EXPLOSION

The mine is recognized as gassy by the Illinois Department of Mines and Minerals and is classified as gassy by the Bureau of Mines. Considerable methane was liberated in the mine during normal operations. At the time of the last regular Federal inspection, the mine was liberating in excess of 616,000 cubic feet of methane in 24 hours. All of the samples collected during that inspection showed some methane, the contents ranging from 0.19 to 1.13 percent. Table 2 contains the analytical results of air samples collected during the investigation. It will be observed that the methane content of the face samples was 0.33 and 0.36 percent, respectively, and the samples collected in return air showed methane ranging from 0.11 to 0.35 percent, although when these samples were collected the volume of air passing through the section was 27,000 cubic feet a minute, compared to a normal quantity of 6,600 cubic feet a minute. While no accumulations of gas were detected during the investigation, although tests were made frequently with a permissible flame safety lamp, the results of the analyses of the air samples indicate that the mine was liberating considerable methane at the time of the explosion, and any interruption of the ventilating current might permit an accumulation of explosive gas in the active workings. This is particularly true under the conditions prevailing in the 13 and 14 east section at the time of the explosion where the active workings were adjacent to vast areas of abandoned workings. These abandoned workings were not sealed, they were not ventilated, the conditions in the abandoned workings did not allow thorough inspections because of squeezing and falls of rock, and they might have contained dangerous accumulations of methane.

FORCES

Only a small area in the 13 and 14 east section was affected by the flame and violence of the explosion. The afterdamp resulting from the combustion of gas and dust passed directly into the main return and none of the other working sections was affected. The forces were extremely violent in some portions of the explosion area, but diminished rapidly due to expansion into abandoned workings. The direction of forces was determined wherever possible by the movement of material, such as the dislodgment of timbers, shattered remains of stoppings and doors, derailment and overturning of cars, scattered debris, and the bending of trolley hangers. The forces were generally outby from the abandoned area explored inby the 9 and 10 south throughout the explosion area. The velocity of the explosion was extremely rapid in the area between the 5 and 6 north and south and 7 and 8 north and south entries, especially in the vicinity of the 7 and 8 north and south entries. The velocity of the explosion diminished rapidly in the vicinity of the 5 and 6 north and south entries and died out completely at 3 and 4 north and south entries. There was considerable evidence of forces traveling into the abandoned 5 and 6 south entries which obviously afforded pressure relief for the explosion.

While there was much evidence of heat and flame in the abandoned area for a distance of 200 feet inby the 9 and 10 south entries, there was slight evidence of force in this area. Indication of forces traveling outby was plainly evident by the position of dislodged timbers and debris. Definite evidence that the forces were traveling outby and increasing in violence as they approached the

active workings was pronounced. The dislodged timbers, overturned cars, bent trolley hangers, the condition of the bodies of the victims, and other evidence indicated clearly that the explosion attained its maximum velocity in the active working section of the 13 and 14 east.

FLAME

The area traversed by the flame of the explosion was determined by a careful examination of the active workings and the accessible parts of the abandoned 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 and clothing, and charred or burnt splinters on timbers left standing in the explosion area. The flame extended throughout the entire explosion area and outby 5 and 6 south. Signs of intense heat and flame were observed particularly in the rooms off 13 parallel entry inby the 8 north entry. Particles of coke, burnt paper, and charred timbers were observed in the accessible area explored along the 13 and 14 east inby the active working places adjacent to the 7 and 8 north and south entries. Numerous streamers of soot were observed hanging from the roof, and heavy deposits of coke and ash were noted on the floor about 200 feet inby the 9 and 10 south entries. The bodies and clothing of all victims of the blast were burned, which proved definitely that the flame extended throughout the entire explosion area.

FACTORS THAT PREVENTED THE SPREAD OF THE EXPLOSION

The explosion was localized and was confined to a small area within the 13 and 14 east section. The 13 and 14 east section was ventilated by a separate air split and the other working sections into which the explosion failed to propagate were not affected by the afterdamp. The main haulage road and active workings were well rock-dusted, the last application of rock dust in the 13 and 14 east section having been made on the night previous to the explosion. The back entries had been rock-dusted by machine during development work, and rock dust was suspended in bags at intervals along the entries. The back entries have numerous falls and the floor was generally covered with incombustible rock, but the abandoned part of the 13 and 14 east inby the 7 and 8 south was coated' with considerable fine coal dust. That the explosion failed to propagate and was confined to a small area because of the recent liberal applications of rock dust to the mine surfaces throughout the active workings, was demonstrated emphatically. The efficacy of the generalized method of rock dusting over any substitute measure as a means of preventing an explosion from propagating throughout the mine was proved conclusively. Another factor in retarding 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.

TABLE 2.-Air analyses report

[Mine: No. 8. Company: Old Ben Coal Corp. Collected: July 25, 1947]

Because of the squeezed and caved condition of the 13 the present active workings, it was only possible to get 9 and 10 north and south panels with reasonable safety.

and 14 east entries inby about 200 feet inby the Here the entries were

squeezed down to about 42 feet in height, and it is believed that a relatively short distance beyond which it was possible to travel these entries that they were caved tight.

For a distance of 200 feet inby the 9 and 10 panels it was observed that there were streamers of soot from the roof and deposits of coke on the floor, indicating slow burning of the gas and dust with little or no violence.

Inby the 9 and 10 panels props that had been broken by the squeeze and which, therefore, would be easily dislodged had not been disturbed.

The absence of violence and the slow burning evidenced by the soot streamers on the roof is a phenomenon often observed in mines following explosions in tight ends where a balanced pressure builds up, such as in a room or entries inby the last crosscut, and substantiates the belief that the 13 and 14 entries were closed tight at some point beyond the 9 and 10 panels.

Outby the 9 and 10 panels heavy deposits of coke were observed, indicating that coal dust entered into the explosion to a large extent, beginning at a point perhaps 100 feet outby the 9 and 10 entries. A build-up of pressure and violence toward the active workings was very apparent. Props and other material had been moved outby. This build-up of pressure and violence unquestionably was due to the ignition of fine coal dust.

As soon as the flame reached the active workings which had recently been thoroughly rock-dusted, a rapid diminution of both flame and violence took place. The further rapid diminution of pressure and violence outby along the 13 and 14 east entries was doubtless due to the release of pressure by expansion into the panel entries that were still open, namely, 7 and 8 north and south, and 5 and 6 north and south.

In view of the above observations it is believed by the investigators that the explosion originated in and was confined almost entirely to the area in which this investigation was conducted.

POSSIBLE CAUSES OF THE EXPLOSION

When the cross entries have been developed to their limit and the rooms off the panel entries have been completed, rooms are driven into the barrier pillars along the cross entries, starting at the inby end and working out, before the territory is abandoned and sealed. During the period of time that is taken to complete this work the worked-out areas squeeze and cave to the extent that these areas cannot be ventilated or inspected properly, although gas may accumulate extensively in the abandoned areas.

There was no doubt that the explosion was caused by an ignition of gas, but the actual source of ignition was not determined positively, although two such sources must be given serious consideration if we are to be sincere in the determination to prevent a recurrence of a disaster of this kind. First, the gathering locomotive was found on the inby end of the return-air side of the split and about 300 feet from the worked-out territory. The nip of the locomotive trailing cable was still connected to the trolley wire and could be construed as evidence that the locomotive was in operation. Reports to the effect that the controller on this locomotive was in the off position could be reasonably discounted, as the natural reaction of the operator when the explosion occurred would be to close the controller. The loading machine had broken down and was partly dismantled, the trailing cable was not connected to the power wire, and the men were loading the coal by hand. The mining machine was parked, and it was stated that no drilling was being done in the places.

Although the evidence points to the fact that the gas was ignited by the locomotive operating at 8 north, the possibility that it was ignited by someone smoking cannot be entirely dismissed. One of the recovery crews about to enter the mine was cautioned against carrying any matches or cigarettes into the mine, and the men deposited numerous packages of cigarettes and matches that they had been carrying in their working clothes at the collar of the shaft, which indicates that the men had been in the habit of carrying smokers' articles into the mine. Even in those mines in Illinois where smoking has been prohibited, it has not been a practice to search the men for smokers' articles before they enter the mine.

The abandoned area inby and immediately adjacent to the last working places off the entries could have contained heavy accumulations of methane that could easily be forced out into the active workings by a fall of roof in any part of the vast expanse of abandoned workings, by a slight change in barometric pressure,

or by restoring the ventilation after it had been disrupted by keeping one of the doors open for an excessive length of time.

It was quite obvious to the men engaged in the recovery operations that the abandoned area adjacent to the active workings was squeezing and caving at that time and undoubtedly had been during the day, and it is an undisputed fact that the liberation of methane becomes more active when caving and squeezing occur. Therefore, it was concluded by the Bureau men engaged in the recovery work and investigation that some accumulated gas had been forced into the active working area, or that gas had accumulated in the working section due to an extended disruption of the ventilating current, where it was ignited by a spark. or are from the gathering locomotive, or possibly by one of the workmen smoking. The State mining board issued a preliminary statement to the effect that an accumulation of gas in the abandoned area was ignited in some unknown manner to cause the explosion. However, the Bureau investigation and subsequent statements of the survivors would seem to indicate that this preliminary statement will be revised in the final report.

Following are the statements of the three men who survived the explosion in the 13 and 14 east entries of the Old Ben Coal Corp. No. 8 mine, July 24, 1947, obtained July 30, 1947.

Statement of Frank Casper, West Frankfort, Ill., motorman for servicing the loading machine:

"As the loading machine was broken down, I decided to walk out of the room to see what was going on in the rest of the section. When I reached the entry switch, I saw the gathering locomotive up at the 8 south entry changing cars for the hand loaders. As I was looking up the entry, I saw a ball of fire start at the locomotive and the fire came down the 13 east entry from the 8 south. I fell to the ground and there was a loud report like a shot, and when the fire reached me it was making a swishing sound. I was picked up by the force and thrown down the entry. The lens and globe in my electric cap lamp were destroyed so I was in the dark. I found one rail and followed it down the entry until I came to a crosscut on the left side. I crawled through the crosscut and came to fresh air and decided to stay there. The first men to reach me were James Rainey, the motor boss, and Don Bowker, the mine manager, and when they arrived I walked out to the mouth of the entry with assistance.

"I did not hear the drill or machine running, but I did hear the locomotive running up at the 8 south switch.

"We had gas up around the 9 and 10 north entries when we were working in the pillars there."

Statement of Charles Smith, West Frankfort, Ill., gathering locomotive operator:

"I had exchanged locomotives with Curtis Stagner, the relay motorman, and in company with Thomas Kirby, the main-line motorman, I was sitting on Stagner's locomtive. After some switching, Stagner had just changed the three hand loaders in the rooms off the 13 east parallel entry. As I was watching him come out on the 13 east entry, I saw a ball of fire and a second later I heard a swishing sound, and Kirby and I were thrown off the locomotive and landed out by it. We were in the dark, as the headpieces of our electric cap lamps were destroyed. I told Kirby that we had better get into the intake air course and started to crawl along the rail. I found a stopping, but there was no opening in it. I called to Kirby and he said that he could not make it any further, so I told him to stay there and I would see if I could find a crosscut with an opening in it. I started to crawl up the entry, but lost consciousness and do not remember anything more until I woke up in the hospital.

"The machine and drills were not being operated at the time of the explosion. "My belief is that the locomotive that Stagner was running ignited the gas at 8 south off 13 east entry."

Statement of Thomas Kirby, West Frankfort, Ill., main-line locomotive operator:

"Charles Smith and I were sitting on Stagner's locomotive at 6 north off 13 east entry. We saw Stagner switching around with his locomotive at 8 south off 13 east and saw a ball of fire. We only had time to turn our heads when we heard a swishing sound and we were thrown off the locomotive. We talked about getting into the intake-air course, and then I lost consciousness.

"I really believe that the locomotive that Stagner was operating at the 8 south off 13 east ignited the gas."