Imágenes de páginas
PDF
EPUB

APPENDIX E

SUPPLEMENTAL STATEMENT BY MR. C. A. HERBERT, SUPERVISING ENGINEER,

VINCENNES, IND. In the report on the explosion at No. 8 mine, Old Ben Coal Corp., West Frankfort, Ill., on July 24, 1947, under the heading Possible Causes of the Explosion the following statement is made:

"Although the evidence points to the fact that gas was ignited by the locomotive operating at 8 north, the possibility that it was ignited by someone smoking cannot be entirely dismissed.”

Mr. C. A. Herbert's supplemental statement contains the following:

"The above statement, concerning smoking as a possible source of ignition in the Old Ben Coal Corp.'s No. 8 mine explosion report, is justified from the facts obtained during the investigation, from intimate knowledge of practices in the Illinois coal field, and from evidence obtained from previous inspections at this mine and other mines in southern Illinois where smoking is practiced surreptitiously in gassy mines.

"The following facts would seem to bear out the asumption that there was a possibility that, smoking might have caused the ignition; therefore, the statement that it should not be entirely dismissed was placed in the report.

"A reinspection report on the No. 8 mine dated August 21-24, 1945, included a recommendation as to smoking. This same recommendation was repeated in the inspection report dated May 14-17, 1946. Company officials also state that they have found evidence of smoking on numerous occasions in this mine.

"It will be noted in the explosion report that the Old Ben No. 8 employees, when requested to search themselves, deposited smokers' materials that were in their working clothes at the shaft collar when they were about to enter the mine to take part in the recovery operations, indicating conclusively that it was general practice to carry smokers' articles into the mine.

“An interview with Mr. David Clayton, coroner, Franklin County, Ill., after the explosion report was transmitted, revealed that about 50 percent of the victims of the disaster had matches and cigarettes on their persons. He stated further that during his 20 years as coroner of Franklin County, he had repeatedly found matches and cigarettes on the bodies of victims over whom he has held inquests.

"Searching the men for smokers' articles has not to our knowldege been practiced in the State of Illinois until recently. Since the exploson at the Old Ben No. 8 mine, the company reports that they are now searching their workmen and no resistance has been offered from the men, who evidently now realize the importance of this safety measure.

"It is no discredit to the survivor to say that they could not have been close enough to the point where the explosion was initiated and lived, to discern whether or not the gas was ignited by a spark or arc from the locomotive or by a man lighting a match to smoke.

“The inspectors have been instructed to cover every possibility in making their investigations and in writing any explosion report. To consider anything less than this would seem unethical to those sincerely interested in the safety of those who work in coal mines.”

FINAL REPORT OF MINE EXPLOSION, NO. 5 MINE, CENTRALIA COAL CO.,

CENTRALIA, MARION COUNTY, ILL., MARCH 25, 1947

(By M. J. Ankeny, W. A. Gallagher, F. J. Smith, Frank Perz, J. S. Malesky)

INTRODUCTION

An explosion occurred in the No. 5 mine of the Centralia Coal Co., 2 miles south of Centralia, Marion County, Ill., at 3:26 p. m., March 25, 1947. The explosion resulted in the death of 111 men, of which number 65 were killed by burns and violence and 46 by after damp. One of the victims of the after damp was rescued and died later on the surface. One hundred and forty-two men were in the mine at the time of the explosion; 24 men escaped unaided, and 8, including the after. damp victim, were rescued.

The explosion was caused by coal dust which was raised into the air and igniter by explosives fired in a dangerous and nonpermissible manner. It was a local explosion, although exceedingly violent in several of the working sections, and it stopped at a point estimated to be 6,400 feet from the shaft bottom. The probable point of origin of the explosion was at the face of 1 west entry.

The mine was dry throughout, with the exception of local “swags," where it was necessary to pump water, and no measures were taken to allay the dust at its source. Parts of the main and secondary haulage roads had been rock-dusted, but no rock dusting had been done in the rooms, or within 500 feet of the faces of the working entries.

The Vincennes office of the Bureau of Mines was notified of the disaster by telephone from the mine office. Federal inspectors in the Vincennes office, and lio of the Health and Safety Division personnel that were available, were dispatched to the scene of the explosion immediately with a fully equipped mine rescue truck. The inspectors in the field were contacted as soon as possible and were told to report at the mine, the first one arriving at 7:45 p. m. Other Bureau of Mines men arrived throughout the night and the following day. A total of 14 representatives of the Bureau of Mines participated in the recovery operations, the investigation, or both.

GENERAL INFORMATION

LOCATION

The No. 5 mine of the Centralia Coal Co. is located about 2 miles south of Centralia, Marion County, Ill., and is served by the Illinois Central Railroad.

Operating officials.-President, H. F: McDonald, 307 North Michigan Avenue; Chicago, Ill. ; vice president, W. E. Young, 307 North Michigan Avenue, Chicago, Ill.; general superintendent, W. J. Johnson, Tuscola, Ill.; assistant superintendent, H. C. Niermann, 614 Cherry Street, Centralia, Ill. ; mine manager, W. H. Brown, 131 South Elm Street, Centralia, Ill.

This is the only mine owned and operated by the company.

EMPLOYEES AND PRODUCTION

Two hundred and sixty-seven men were employed at this mine; 50 on the surface and 217 underground. Of the 217 underground employees, 75 worked on the night shift. The average daily production was 2,229 tons of coal.

OPENINGS AND NATURE OF COAL BED

The mine is opened by two wood-lined shafts, consisting of a main hoisting shaft 540 feet in depth, through which coal, supplies, refuse, and employees are handled, and a double-compartment downcast air shaft 537 feet in depth and 1,200 feet from the hoisting shaft. One compartment was equipped with a substantial wooden and steel stairway. The coal-hoisting shaft served as the main air outlet. The shafts were in good condition.

The mine is operated in the Illinois No. 6 coal bed, which averages 76 inches in thickness in the present working areas. The coal bed lies flat except for local dips. The cover over the coal bed ranges from 520 feet to 575 feet at this property.

The immediate roof overlying the coal bed is a medium hard black shale ranging from 1 foot to 5 feet in thickness. The main roof consists of strong limestone approximately 30 feet in thickness. Numerous slips and pots are present.

The floor underlying the coal bed is smooth, medium hard fire clay.

COAL ANALYSIS

The following analysis on an "as received" basis of the No. 6 coal bed was obtained from the company and was a composite of four face samples collected in the No. 5 mine.

Percent Moisture_

10.30 Ash--

11.93 Volatile matter

35. 55 Fixed carbon.

42. 22

The ratio of volatile matter to total combustible matter, as given above,

Volatile matter

Volatile matter+fixed carbon is 0.45 for the No. 6 coal bed in this mine.

MINING METHODS, CONDITIONS, AND EQUIPMENT

MINING METHODS

The room-and-pillar method of mining was followed, and pillars were not extracted. The main entries were driven two and three abreast, and room entries were turned right and left off the main entries in pairs, except for the 20, 21, and 22 north triple entries turned off 4 west. The mining plan in the 1 and 2 west section had been changed recently to provide a six-entry system for developing the main entries and to establish a split system of ventilation. The room entries were turned off the main entries at 800-foot intervals; entries were driven 12 feet in width,

Rooms, 28 and 30 feet in width, were turned on 60-foot centers off the headings and air courses and were driven to a depth of 400 feet. Room and entry crosscuts were made at 60-foot intervals.

The coal was under cut to a depth of 81% feet with nonpermissible shortwall mining machines, and was drilled with nonpermissible post-mounted electric drills. All coal was loaded into mine cars and shuttle cars with non permissible caterpillar-mounted loading machines.

A systematic method of timbering the working places was being followed, but safety posts were not set between the permanent timbers and the working faces.

VENTILATION AND GASES Ventilation was provided by a 7-foot aeroplane-propellor-type fan operated blowing and located about 100 feet from the bottom of the intake air shaft. The fan was driven by a 30-horsepower 250-volt direct-current motor. Auxiliary power was provided, and a 220-volt alternating-current power sources was available in the event of failure of the direct-current motor or power. The fan was installed in the center of the entry and was encased in concrete. The power circuit to the fan was independent of the regular mine circuit. During the Federal inspection of March 17-20, 1947, the fan was delivering 72,320 cubic feet of air a minute into the mine at a water-gage pressure of 1.3 inches. The direction of the air flow was readily reversible. A pressure-recording gage, air-lock doors to the fan, and an audible warning device in the engine room were provided. The fan was run continuously and was inspected daily by the electrician.

One continuous air circuit utilizing doors and an overcast was used to ventilate the entire mine. The 1 west haulage way was in intake air to the first working section, and the 4 west and main south haulage ways and hoisting shaft were in return air.

Crosscuts were made at 60-foot intervals and not more than one open crosscut was permitted between the faces of entries and first outby temporary or permanent stoppings.

A few concrete block stoppings had been erected along the 1 west and 4 west haulage ways. All other stoppings were of wooden construction.

One set of air-lock doors were erected near the mouth of 1 west off main south. The doors were only 70 feet apart and necessitated the opening of both doors when a trip was passing. A single door was erected between 13 and 14 north off 1 west and it was attended constantly. All other main doors were erected in pairs to provide adequate air locks. Check curtains were often used near the faces and on the shuttle car sections.

The mine was considered to be gassy by the Federal Bureau of Mines, but was not so considered by the Illinois Department of Mines and Minerals. Two certified mine examiners were employed to make preshift examinations of the mine for gas and to observe and inspect for other hazards, but such examinations were started 8 hours before the first shift entered the mine. An uncertified mine examiner made a preshift examination of the working faces about 2 hours before the second shift entered the mine. Examinations for gas were not made during the working shift.

Many oil and gas wells penetrated the coal bed, but none were in open workings in the mine.

During the Federal inspections of September 1942 and July 1945, the analytical results of two air samples collected near the faces of active workings showed 0.38 and 0.70 percent methane respectively, but there is no record of methane ever having been detected with a flame safety lamp. During the time of the last Federal inspection, March 17-20, 1947, there were eight air samples collected - and the analytical results showed methane ranging from 0.03 to 0.10 percent. is follows:

Percent Face No. 7 room off 21 north.

0.0 Full return at shaft bottomMain return at main south overcast Face No. 14 room off 19 north-Last crosscut between 23-24 south off 4 westLast crosscut between 20-21 north off 4 west· Second crosscut back from face of 1 west air course entryFace No. 37 room off 22 north 4 west_

During the March 1947 Federal inspection, the mine was liberating methane at a calculated rate of 63,072 cubic feet in a 24-hour period.

DRAINAGE

The mine workings and haulage roads were dry, except for accumulations of water in several small sumps along the 4' west haulage road, at 3 north, which were pumped periodically into abandoned workings by a small centrifugal pump An electrically driven pump was located at the shaft bottom and was used to pump the water out of the hoisting shaft sump. Two plunger-type pumps, each of 250-gallon capacity, were located in the main pumping station at 8 north 1 west and were used to pump water from the abandoned area in the main north to the surface.

DUST

The mine was exceedingly dry and dusty and heavy deposits of coal dust were present along the roadways in working places and on the roof, ribs, and timbers in working sections. Heavy deposits of coal dust existed along the roadways in room entries and in the center of the main haulage road on 4 west. Very little effort had been made to load out excessive quantities of dust, and watering methods had not been employed to allay the dust at its source. Rock dust had been applied to the roof, ribs, and roads of active haulage entries, but such rock dusting was not maintained close enough to the working faces, and rock dust was not applied in rooms. In active entries, the rock-dusted zones at the time of the explosion terminated at the following locations : 23 and 24 south 4 west, 900 feet outby from face; 20, 21, and 22 north 4 west, 850 feet outby from face; 1 west, 1,000 feet outby from face; 18 and 19 north 1 west, 600 feet outby from face; 13 and 14 north 1 west, 500 feet outby from face; 20 and 21 north 1 west,

none.

The analytical results of dust samples collected in rock-dusted zones by a Federal coal-mine inspector during the course of a Federal inspection previous to the disaster on March 17-20, 1947, are shown in the following table:

Sample of dust

From

Location in mine

Combus- Incomtible bustible

i 36.6

77.9

59.0

Roof and rib.
Road
Roof and rib.
Road
Roof and rib
Road,
Roof and rib
Road.
Roof and rib
Road.
Roof and rib
Road.

14 north room entry haulage road at No. 16 room

.do.
18 north room entry haulage road at the No. 5 room.

do.
Main south haulage road in by machine shop.

do
24 south room entry haulage road off 4 west at No. 4 room.

do
Main 18 south haulage road at 4 west intersection.

do...
Main south haulage road at 4 west

45.8
49.6
22.1
63.4
41.0
59.5
10.6
50.8
25.6
51. 2
26.5
47.5

89.4 49. 2

48.8 73.5 52. 2

do....

It will be observed from this table that none of the road samples contained the 65 percent incombustible matter recommended by the Bureau of Mines and that two of the roof and rib samples contained less than 65 percent incombustible matter, while four of the roof and rib samples contained more than 65 percent. It is concluded, therefore, that the haulage roads were not being redusted with sufficient frequency; however, this deficiency was not a factor in this explosion.

Additional dust samples were collected during the investigation of the explosion, the analytical results of which are shown in table 1.

[blocks in formation]

58 51 59 34 50 38 43 49 73 79 53 46 31 39

Yes.

42 49 41 66 50 62 57 51 27 21 47 54 69 61 66 56 63 64

U-724.. Rib and roof.. At Room 15, 14 north 1 west. Yes.
L-377.
Road.
do...

Yes.
H-837.. Rib and roof.. At Room 15, 13 north 1 west...

Yes.
E-529. Road.
..do..

Yes.
V-853. Rib and roof. On 1 west 100 feet outby 14 north. Yes.
Q-378. Road..
do.

Yes.
0-770. Rib and roof. On 2 west 100 feet out-by 14 north. Yes.
X-865 Road.
do.

Yes.
B-871. Rib and roof.. On 4 west 100 feet out-by 18 north.
T-258.. Road.
do.

Yes.
S-244. Rib and roof.. On 3 west 100 feet out-by 18 north. Yes.
0-972.. Road.
do..

Yes.
X-663 Rib
At room 25, 21 north 4 west.

No..
U-667 Road
do..

No.
H-915. Rib and roof.. At room 25, 22 north 4 west. No.
L-321. Road.
do...

No..
F-477. Rib and roof. On 2 west 150 feet out-by 18 north. No.
P-612. Road

No..
L-531 Rib and roof. On 1 west 150 feet out-by 18 north. Yes.
H-873.. Road....
...do

Yes.
B-340.. Rib and road. On 1 west 250 feet inby 19 north.. No..
B-665.. Road.
..do..

No..
X-492 Rib and roof. On 2 west 250 feet inby 19 north. No..
Road.
.do.

No..
B-166. Rib and roof.. At room 35, 19 north 4 west.

Yes H-698. Road.. do.

Yes. G-108. Rib and roof.. At room 35, 18 north 4 west.

Yes. X-101. Road.. do..

Yes. H-651.. Rib and roof. At room 17, 18 north 1 west

No.
V-595.. Road..
do..

No.
C-681.
Rib and road.. At room 17, 19 north 1 west.

No..
C-141. Road..
..do...

No..

None.

Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.

Do.
Medium amount.
Small amount.
Medium amount.
Small amount.

Do.
Very sma

all
amount.
Small amount.
Trace.
Small amount.

Do.
Do.

34

44 37 36

...do.

43 38 30 34 29 29 44

9-337

Do.

57 62 70 66 71 71 56 66 55 60 68 69 62 68

34

45 40 32 31 38 32

None.

Do.
Do.

Do.
Large amount.
Very large amount.
Large amount.
Very large amount.

It may be observed from this table that rib and roof samples collected from rock-dusted areas in the portion of the mine affected by the explosion contained from 43 to 73 percent incombustible matter and averaged 52 percent. Road samples collected at the same locations contained from 37 to 79 percent incombustible matter and averaged 45 percent. Attention is called to the fact that some of these samples were contaminated by coal dust carried and deposited by the explosion. Rib and roof samples collected from non-rock-dusted areas in the active working sections affected by the explosion contained from 29 percent incombustible matter to 38 percent incombustible matter and averaged 33 percent. Road samples collected at the same locations contained from 31 percent to 39 percent incombustible matter and averaged 35 percent. Coked particles were present in varying amounts in all of the samples collected in non-rock-dusted areas, indicating that all of these locations were closely involved in the explosion.

Explosibility tests on the Illinois No. 6 coal bed, conducted at the Bureau of Mines experimental mine at Bruceton, Pa. (see Bulletin 167, p. 249), indicated that this coal dust required the presence of 33 percent incombustible matter to prevent ignition when no gas was present and required the presence of 59 percent incombustible matter to prevent propagation under the same conditions. It is concluded from this that much of the untreated dust in the face regions was capable of initiating and propagating an explosion, while the dust on the

92725—49

21

« AnteriorContinuar »