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Coal was mined with continuous-mining machines, and pillars were extracted by the pocket-and-wing method. Approximately 12 inches of draw slate was mined with the coal seam. The immediate roof was about 12 inches of wild coal overlain with laminated shale and coal of varying thicknesses, The main roof was sandstone. Minimum standards for support, utilizing roof bolts supplemented with wooden planks, wooden cap blocks, posts, steel beams, and hydraulic roof jacks, had been adopted and at the close of this inspection were followed in accordance with the plans outlined by the Bureau's roof-control investigator, Roof bolts were installed on H-foot centers lengthwise and crosswise in 16-foot wide entries, crosscuts, and pillar pockets to within 4 feet of the face before mining was started, Breaker posts and hydraulic jacks were required to be set in openings to the gob during pillar extraction. The plan appeared to be adequate for the roof conditions observed during this inspection.
The mine is classed gassy in accordance with the laws of the State. A split system of ventilation was used to ventilate the working sections. The quantity of air passing through the last open crosscuts in developing sections varied from 13,000 to 28,000 cubic feet a minute and the quantity of air entering the intake ends of pillar lines varied from 52,000 to 57,000 cubic feet a minute, Plastic line brattice installed exhausting from the last open crosscut and maintained to within 8 feet of the faces and plastic checks were used to direct the air to the working faces. The line brattice was secured on wooden framework constructed after each advance of the continuous-mining machine. Ventilation at the working faces was adequate.
Suitable preshift, onshift, and weekly examinations of the mine were made, and the results of these examinations were properly recorded. Neither methane nor an oxygen deficiency was indicated by means of a permissible flame safety lamp during this inspection. The analyses of air samples collected in the split returns of the working sections and in the main return airways at the bottom of the Spinner and Cherokee shafts are shown in table 1. Methane monitors were installed on two of the continuous-mining machines,
The mine surfaces varied from wet to dry, Dangerous accumulations of loose coal and coal dust were not observed. The cleanup of loose coal and coal dust and the application of rock dust were included as part of the mining cycle, Rock dust was applied to the roof and ribs by compressed-air-operated rock-dust machines and to the floor by hand after each advance and cleanup of the working faces, Followup rockdusting was done between shifts and on weekends by high-pressure and bulk-dusting machines, Compressed-air-operated rock-dust distributors were installed and operated continuously in the immediate return from each working place while coal was mined at the face. Water was used to allay dust at the faces and at all loading points, Dust resulting from drilling roof-bolt holes was collected by permissible dust collectors.
Spot-location dust samples were not collected during this inspection. Rock dust had been applied to the mine surfaces and maintained within 40 feet of the faces including all open crosscuts, except the floor of No. 6 split 1 main 55 room section was not adequately rock-dusted, This area was rerock-dusted promptly. Dust surveys were made in seven developing sections, the analyses of which are shown in table 3. The samples were collected at predetermined intervals of 300 feet in all sections, except 51 and 55 room sections in 1 main 5 flat where the samples were collected at 200-foot intervals. A dust sample was collected in every third crosscut of each entry. A total of 376 dust samples was collected, all of which contained more than 65 percent incombustible material. The mine, including the back and parallel entries, appeared to be adequately rock-dusted at the close of this Inspection,
Eiectric face equipment was permissible type and maintained free of dust and grease accumulations, Defects found in permissible electric face equipment were corrected promptly. Overload protection was provided. Trailing cables were flame-resistant types and were provided with short-circuit protection. Tests for gas were made in face regions before electric face equipment was energized at the beginning of the shift, before the equipment was taken inby the last open crosscut, and at frequent intervals while the equipment was being operated in the face regions.
Gas and oil wells were plotted on the mine map. Blocks of coal of sufficient size were left intact around these wells where they were encountered in the active workings of the mine. Active workings were not approaching adjacent mines.
Emergency escapeways were provided from each working section to the surface. The escapeways were well marked and maintained reasonably free of standing water and roof falls, except a roof fall in the escapeway from 2 main straight made travel difficult in this escapeway.
The Joint Industry Safety Committee in Appeal Docket No, A-536, dated September 20, 1966, granted an exemption from the requirements of Article VII, Section 6c, of the Federal Mine Safety Code concerning the use of reflectors in lieu of permissible trip lights. The recommendations of the Committee were being complied with at the time of this inspection,
A well-equipped mine rescue station for the corporation's mines in the Brick District is located at the Colvin shaft portal, Robena No. 1 mine, A report covering the inspection of the station is included as a supplement to the inspection report of Robena mine (Nos, 1, 2, 3, and 4).
The importance of complying with the provisions of the Federal Coal Mine Safety Act and the Federal Mine Safety Code between inspections was discussed with management,
FEDERAL COAL MINE SAFETY ACT
Violation - Section 209 e 5)
The floor of No, 6 split between Nos, 53 and 54 rooms was not adequately rock-dusted in 1 main 55 room section. A Notice (Form 203(a)) was issued at 11:30 a.m. December 15, 1969, requiring the violation to be abated by 12:15 p.m. December 15. The violation was totally abated in the prescribed time.
Violation - Section 209(f) (1)
A conduit was out of the clamp on the left cutting motor of No. 8
There was an opening in excess of 0.007 inch in the left traction motor of No. 51 shuttle car in i flat 2 main 5 room section. A Notice (Form 203(a)) was issued at 12:05 p.m. December 3, 1969, requiring the violation to be abated by 12:45 p.m. December 3. The violation was totally abated in the prescribed time,
Violation Section 209(f)(1) There was an opening in excess of 0.006 inch in the left conveyor motor of No. 54 shuttle car in 1 main 6 flat section right side. A Notice (Form 203(a)) was issued at 11 a.m. December 16, 1969, re the violation to be abated by 11:30 a.m. December 16. The violation was totally abated in the time prescribed.
Section 1a, Roof bolts in a chute from A to B tracks in 2 main straight were installed 32 inches apart crosswise leaving a wide space between the outside bolts and the ribs. Also, roof bolts in 1 main 5 flat in Nos, 51 and 52 rooms were spaced 52 inches apart lengthwise and crosswise,
Explosives and Blasting
Section 4a. There was an open cardboard container of explosives stored in No, 4 crosscut between Nos, 20 and 25 rooms section in 2 main 2 flat,
Section 4d. 1. The clearance space along C track (outbound track) river portal entries between Nos, -60 and 65 crosscuts was obstructed with mud and track cleanings, and the clearance space out by the loading ramp in 1 main straight left side was obstructed with roof bolts,
No action taken
Section 6e. A motorman was observed backpoling on A track 2 main at 4 flat switch.
This hazard was partially abated. The mine foreman instructed the motorman of the dangers involved while backpoling.
Section 6j. Cars standing in sidetracks in 1 main 6 flat, 1 main 5 flat, and in 2 main 4 flat were not blocked or spragged,
No action taken
Section 6p. Locomotives were observed following other trips on 2 main 4 flat and Ginger Hill haulage roads less than 300 feet behind and were not coupled to the trips.
No action taken
Section 6r. The operator of a portal bus moved from the bottom of Cherokee shaft across the main outbound haulage track without orders from the dispatcher.
This hazard was partially abated. The portal bus operator was instructed to move the portal bus only after he was advised to do so by the dispatcher,
Article VIII Electricity Section 4n. The trolley wire was less than 6-1/2 feet above the top of the rail and was not guarded where workmen were carrying pipe under the wire in 2 main 2 flat 25 room section. The trolley wire was guarded only on one side at No. 1 chute 2 main 3 flat 45 room section and at the sanding station in 2 main 4 flat on the right side,
Safeguards for Mechanical Equipment
Section 1a, The continuous-mining-machine operators in 2 main 2 flat 20 room section, 2 main 4 flat right side, and 1 main 5 flat 51 room section did not use the means provided for locking the cutting bits while the machines were being trammed or parked,
This hazard was partially abated. The continuous-mining-machine operators were instructed to use the means provided for locking the cutting bits while the machines were being trammed or parked,
Section 481. The emergency escapeway from 2 main straight was partially obstructed by a roof fall.
Richard H. Peid
Richard H. Reid