The power wires in 2 right for the battery charger, the pressure pump, and the control cable along the belt conveyor were in contact with combustible material at many locations. A Notice of Violation No. 6 was issued April 7, 1970, on Form 104. (b) requiring that this violation be abated by 8 a.m. on April 8, 1970, and a Notice of Penalty No. 6 pertaining thereto was issued April 7, 1970. This violation was totally abated in the time set. Sanitary toilet facilities were not provided in south mains crossover. A Notice of Violation No. 1 was issued April 8, 1970, on Form 104. (b) requiring that this violation be abated by 8 a.m, on May 15, 1970, and a Notice of Penalty No. 1 pertaining thereto was issued April 8, 1970. Violation Section 75.1101 Deluge-type water sprays or foam generators automatically actuated by a rise in temperature or other no less effective means approved by the Secretary of controlling fire were not installed at south mains crossover belt drive. A Notice of Violation No. 2 was issued April 8, 1970, on Form 104. (b) requiring that this violation be abated by 8 a.m. on May 15, 1970, and a Notice of Penalty No. 2 pertaining thereto was issued April 8, 1970. Potable water for drinking purposes was not provided in the active working section in south main crossover. A Notice of Violation No. 3 was issued April 8, 1970, on Form 104. (b) requiring that this violation be abated by 8 a.m. on April 15, 1970, and a Notice of Penalty No. 3 pertaining thereto was issued April 8, 1970. Violation - Section 75.1100 Waterlines parallel to the track-haulage entry equipped with outlets at intervals of 500 feet and 1,000 feet of firehose with suitable fittings at strategic locations, or two portable water cars were not provided in the mine. A Notice of Violation No. 4 was issued April 8, 1970, on Form 104. (b) requiring that this violation be abated by 8 a.m. on May 15, 1970, and a Notice of Penalty No. 4 pertaining thereto was issued April 8, 1970. Directive Safeguard Section 75.1403 Positive stopblocks or derails were not provided in the track near the top and at the slope landing. A directive No. 1 was issued April 8, 1970, requiring that this condition be abated by 8 a.m. on April 15, 1970. UNITED STATES DEPARTMENT OF THE INTERIOR Coal Mine Health and Safety District A REPORT OF COAL-MINE EXPLOSION THE HELEN MINING COMPANY HOMER CITY, INDIANA COUNTY, PENNSYLVANIA April 10, 1970 By Ralph I. Krek Federal Coal-Mine Inspector (Electrical) Warren K. Lewis Federal Coal-Mine Inspector and Harry C. Thompson Federal Coal-Mine Inspector A Originating Office Bureau of Mines Federal Building U.S. Post Office, Johnstown, Pennsylvania 15901 Johnstown, Pennsylvania, Subdistrict, Coal Mine Health and Safety District A A REPORT OF COAL-MINE EXPLOSION HOMER CITY MINE THE HELEN MINING COMPANY HOMER CITY, INDIANA COUNTY, PENNSYLVANIA April 10, 1970 By Ralph I. Krek Federal Coal-Mine Inspector (Electrical) Warren K. Lewis Federal Coal-Mine Inspector and Harry C. Thompson Federal Coal-Mine Inspector INTRODUCTION This report is based on an investigation made pursuant to the Federal Coal Mine Health and Safety Act of 1969 (83 Stat. 742). A gas explosion occurred at 3:40 a.m., Friday, April 10, 1970, at the face of No. 7 entry of the crossover mains section in the Homer City mine. Fifteen men were working in the section at the time. One man died from asphyxiation due to carbon monoxide and smoke inhalation, and three men suffered burns and were hospitalized in the Indiana Hospital, Indiana, Pennsylvania. Nineteen men working in other parts of the mine were not affected by the explosion. Appendix A lists the names of the victims and other pertinent information. Bureau of Mines investigators believe that an explosive mixture of methane and air was ignited by frictional sparks created when the cutting bits of a Joy 11CM-1AKK continuous-mining machine struck sandstone over the coalbed. The flame spread for a distance of about 152 feet out by the face of No. 7 entry, and about 170 feet into the last open crosscuts between Nos. 5, 6, and 7 entries. Forces of the explosion damaged three overcasts over south mains at the entrance to No. 7 entry of crossover mains, a distance of 300 to 450 feet outby the face, and blew out a number of plastic brattice-cloth checks and line curtains in the crossover and south mains sections, see Appendix F. GENERAL INFORMATION The Homer City mine is near Homer City, Indiana County, Pennsylvania, and the coal produced is transported by overland belt conveyors to the Homer City electric generating station. The mine is opened by a double-compartment slope, 2,500 feet long, and a 15-foot-diameter shaft, 608 feet in depth, into the low-volatile Upper Freeport coalbed, which ranges from 44 to 54 inches in thickness in the area being mined. A total of 138 men was employed and 108 worked underground on 3 shifts a day, 5 days a week. The average daily production of 1,200 tons of coal was mined and loaded with continuous-mining machines. The immediate roof consists of sandstone or hard shale, and where shale is present, it varies from 10 to 15 feet in thickness. The main roof is sandstone. The anlaysis of a coal sample taken from the coalbed in this mine, as obtained from the coal company is as follows: Numerous tests by the Bureau of Mines have shown that coal dust having a volatile ratio of 0.12 and higher is explosive. The volatile ratio of the coal in this mine as determined from the foregoing analysis is 0.25, indicating that the coal dust is explosive. The last Federal inspection of this mine was completed December 2, 1969. A partial but representative inspection of the mine was completed April 8, 1970. Immediately after the investigation of this explosion was completed, a spot inspection of the entire mine was made because the mine was idle and numerous violations of the Act were cited. Violations that do not relate directly to the explosion are not discussed in this report. MINING METHODS, CONDITIONS, AND EQUIPMENT Mining Methods The mine was in the process of development by a block system, and only entries were being driven. The entries, in sets of seven, were 18 to 20 feet wide, and crosscuts were 80 to 100 feet apart and 18 to 20 feet wide. Roof-support plans had been adopted and were followed. Roof bolts were being installed in accordance with recommendations made by the United States Bureau of Mines. Explosives Mining in the crossover mains section was done with continuous-mining machines. Explosives were not used or stored in the section. Ventilation and Gases Ventilation in the mine was induced by an axial-flow fan installed properly on the surface and equipped with all required safety devices. The fan was operated continuously and was exhausting about 168,000 cubic feet of air a minute from the mine. A split system of ventilation was used, employing concrete-block and concrete permanent stoppings, overcasts, and under casts. The crossover mains section was ventilated by a current of intake air directed through No. 6 entry of south mains and then split right and left at No. 1 entry of crossover mains. The right split ventilated two mechanical units operating in the seven entries of the crossover mains and returned through No. 7 entry. The left split ventilated the seven entries of south mains in which two mechanical units were also operated and returned through No. 1 entry of south mains. See Appendix G. The air was conducted to the working faces with line brattices and runthrough check curtains constructed of nylon plastic material. At the time of the explosion, the end of the line brattice in No. 7 entry of the crossover mains was 27 feet from the face of a sump cut being driven and about 4 feet from the back end of the continuous-mining machine, a bulky machine which virtually filled the sump cut and was not provided with auxiliary means for ventilating the face. The end of a line brattice in a working place of a nearby section was 54 feet from the face. The development of two sets of seven entries to the south and to the west in close proximity simultaneously necessitated the use of many temporary stoppings, check curtains, and line brattices, all constructed of nylon plastic material. This made control of the ventilation in these sections difficult. |