A coal dust explosion occurred in the interconnected Nos. 15 and 16 mines of the Finley Coal Company, Hyden, Leslie County, Kentucky, about 12:20 p.m., Wednesday, December 30, 1970.  Thirty-eight of the 39 men who were underground at the time were killed.  Observations made during the investigation of the disaster indicate that 14 men who were employed in No. 16 mine were apparently killed instantly by the explosion, and 3 others who may have moved a short distance after the explosion possibly died from asphyxiation or carbon monoxide poisoning.  Nineteen men, who were employed in No. 15 mine, were apparently killed instantly by the explosion, and 2 others who may have moved a short distance after the explosion presumably died from asphyxiation or carbon monoxide poisoning.  The lone survivor was near the portal in the belt entry of No. 15 mine when the explosion occurred.  He was injured slightly by the explosion force and the debris coming out of the mine.

The Bureau's investigation of the disaster included extensive examinations of the underground workings of the Finley Coal Company mines following the disaster, a public hearing held at Hyden on January 6, 1971, a study of all previous reports on inspections and accident investigations at the mines, and interviews of all but 13 Finley Coal Company employees.  On the basis of this investigation, the Bureau has concluded that the explosion occurred when coal dust was thrown into suspension and ignited by Primacord, by permissible explosives used in a nonpermissible manner, or by use of nonpermissibly explosives during the blasting of roof rock for a loading point (boom hole).  These practices are not permitted under the Act.  Excessive accumulations of coal dust and inadequate applications of rock dust in parts of Nos. 15 and 16 mines permitted propagation of the explosion throughout the mines.

General Information

The Nos. 15 and 16 mines are on Hurricane Creek off State highway 80 about 4 miles east of Hyden, Kentucky.  Coal from these mines is hauled by autotruck to a preparation plant on a siding of the Louisville and Nashville Railroad Company at Sibert, Kentucky.

A total of 100 men was employed, of which 95 worked underground on 2 coal-producing shifts and 1 maintenance shift a day, 5 days a week.  An average of 1,500 tons of coal a day was loaded by mobile loading machines into rubber-tired mine cars.  The immediate and main roof was generally firm shale, and the floor was also firm shale.

The volatile ratio of the coal in these mines is 0.42, indicating that the coal dust is highly explosive.

Mine Conditions Immediately Prior to the Explosion

Cold and cloudy weather prevailed in the vicinity of the mines on December 30, 1970.

The report of the mine examiner (fire boss) for the 7:00 a.m. to 3:00 p.m. production shift on December 30, 1970, stated that all places in No. 15 mine were visited and all places were ready for the day shift.  Investigators could no find a record of No. 16 mine being examined.  The preshift record book indicates that only the working places in No. 15 mine were examined on December 30, 1970; however, further evidence obtained upon questioning the employee who made the examination revealed that the preshift examination listed in the record book for No. 15 mine was actually for the examination made in No. 16 mine and that someone else made the examination in No. 15 mine.  It was learned upon questioning the man who made the examination of No. 15 mine that he made an examination of the working places in No. 15 mine and recorded the results in the record book on the surface; a record of this examination could not be located.  The preshift examination record books were incomplete in that they did not indicate the time the examiner entered the mine and returned to the surface, the area or areas of the mines examined, whether methane or oxygen deficiency was detected, whether the air in the mine was traveling in its proper course and at normal volume, and the quantity of air reaching the last open crosscuts in the entries.

Evidence of Actitivities Prior to Explosion

The day-shift crew, consisting of 39 men, entered the mines about 6:45 a.m., December 30, 1970, and were transported in rubber-tired trailers to their respective working stations.  Apparently, routine coal-loading operations were in progress on each of the two conventional loading sections until shortly before the explosion.

During the official hearing at Hyden, A. T. Collins, utility man (beltman), testified that he entered No. 15 mine at 7:00 a.m., returned to the surface at 11:30 a.m., and observed no unusual conditions in the mine.  Collins also stated that he saw Primacord in the mine some time before Christmas and was instructed by the superintendent to hide the Primacord.  He stated that the superintendent told him at about 11:00 a.m. on December 30, 1970, that he had a man in the mine to shoot a couple of holes and that the blast would be light, but indicated by a wink and a nudge that the blast would be something unusual.

At 3:00 p.m. on December 30, 1970, State and Federal inspectors entered the No. 3 portal of No. 15 mine and traveled without the air of breathing apparatus to No. 24 crosscut between Nos. 3 and 4 main entries before encountering any difficulty with carbon monoxide or smoke - although concrete block stoppings in 12 crosscuts outby the No. 24 crosscut were either partly or completely blown out.  Travel between Nos. 24 and 30 crosscuts was accomplished with the use of gas masks, and three bodies were located in the vicinity of Nos. 29 and 30 crosscuts.

At 4:30 p.m. on December 30, State and Federal inspectors and a company employee entered No. 16 mine via No. 4 main entry, and were able to travel to No. 20 crosscut before encountering high concentrations of carbon monoxide between Nos. 3 and 4 main entries.  Brattice cloth was used to replace blown out stoppings, and the crew continued its exploration into the mine.  The crew reached the mouth of No. 3 entry, 1 left, about 7:00 p.m.  There the first body was found, and exploration of the 1 left section was continued.  In all, 15 bodies were found before the crew encountered excessive carbon monoxide and decided to return to the surface with 3 of the bodies at 8:00 p.m. on December 30.

Additional recovery crews composed of State and Federal inspectors, company officials and employees, and volunteer officials and employees from other mines in eastern Kentucky, entered Nos. 15 and 16 mines at various times during the night of December 30 and the morning of December 31 to relieve or to assist crews in repairing or replacing damaged and blown out stoppings or to assist in recovery of bodies.  The recovery work was completed, and the last body was brought to the surface at 10:00 a.m., December 31, 1970.

Evidence noted during the recovery operations, such as position and location of victims in addition to their physical appearance, is cause for Bureau of Mines investigators to conclude that all but 5 of the victims were apparently killed immediately by the explosion.

Investigation of Cause of Explosion

Methane and/or Dust as a Factor in the Explosion

Mine records indicate that methane has not been detected in Nos. 15 and 16 mines by company officials.

During the underground investigation of the explosion, it was evident that coal dust propagated the explosion.  Evidence of pressure and/or explosion forces was found at numerous locations, and evidence of burning coal dust, such as soot streamers and heavy deposits of coke, was found.  The floor, roof, and ribs of the active 1 left sections (explosion area) were dry, and excessive accumulations of loose coal and coal dust were present in the tractor roadway and in the area where the explosion originated.  It was apparent that rock dust had been applied.  The quantity, however, was inadequate.

Summary of Evidence

Conditions observed in the mines during the investigation following the explosion, together with information available from Federal coal mine inspection and investigation reports and from company officials, workmen, and mine records, provided evidence as to the cause and origin of the explosion.  Those paragraphs marked with an asterisk indicate conditions or practices that contributed to the explosions:

• This was a dust explosion, and there was no evidence indicating that methane entered into the explosion.
  
  
• Most of the victims were burned in some degree, which proves there was flame and intensive head.
  
  
• Coal dust, including float coal dust, was deposited on rock-dusted surfaces, and loose coal and accumulations of coal dust were observed in parts of Nos. 15 and 16 mines.  Rock dusting was substandard preceding the explosion.  Testimony revealed that water was not being used to allay dust during cutting and loading operations, although the 1 left sections was supplied with water through a 2-inch pipeline.
  
  
• Two spools containing Primacord were found in the mines following the explosion, and short pieces of Primacord were found near the boom hole that was blasted on the day of the explosion.  While moving the rock blasted from the boom hole, additional Primacord and one detonator leg wire were found.
  
  
• While moving the rock blasted from the boom hole, additional Primacord and one detonator leg wire were found.  Primacord is detonation by one detonator.  If the shots had been fired electrically with a detonator (each with two leg wires) in each shot hole, a large number of such leg wires would have been found.
  
  
• According to evidence given by various persons during the investigation, boom holes had been blasted with Primacord, and the charges were improperly secured with paper of brattice cloth.
  
  
• According to testimony of some of the persons responsible for or actually engaged in the blasting of boom holes, all shots in a boom hole, 45 to more than 100, were fired at the same time from power cables or from the battery connections of battery-powered tractors (48-64 volts)
  
  
• Unsafe practices in handling explosives in these mines were discovered during the investigation of a nonfatal explosives accident that occurred in No. 15 mine on August 12, 1970.
  
  
• Additional rock dust was not applied in the vicinity of boom holes before blasting.
  
  
• Evidence of smoking underground, such as burnt matches, cigarette butts, and empty cigarette packages, was observed at numerous locations in the mines during the recovery operations and ensuing investigation, and opened packages of cigarettes were observed in the pockets on the bodies of some of the victims.  A suitable search program for smoking materials and flame making devices was not in effect at the mines as evidences by these conditions and practices.
  
  
• A sample of explosive found in a shot hole for a boom hole that was blasted earlier was determine to be 40 percent strength dynamite.

Cause of Explosion

It is the conclusion of the Bureau of Mines that the explosion occurred when coal dust was thrown into suspension and ignited by Primacord or by permissible explosives used in a nonpermissible manner or by use of nonpermissible explosives during the blasting of roof rock for a loading point (boom hole).  Excessive accumulations of coal dust, and inadequate applications of rock dust in parts of Nos. 15 and 16 mines, permitted propagation of the explosion throughout the mines.

Source of Information:
	Historical Summary of Mine Disasters in the United States - Volume II