FIGURE 2-Gases and smoke from Tonopah-Belmont mine fire.

TABLE 1.- Accidents from fires in metal mines, all underground mine operations1

Adams, W. W., and Kennedy, F. J., Accidents at Metal and Nonmetal Mines in the United States, 1942: Bureau of Mines Bull. 461, 1945, 81 pp.

2 Less than 0.1 percent.

3 Less than 0.01 percent.

GRANITE MOUNTAIN SHAFT FIRE, BUTTE, MONT.3

A fire in one of the two main shafts of the North Butte mine, an underground copper property operated by the North Butte Mining Co., on the night of June 8, 1917, caused the death of 163 men-the greatest number killed in any American metal-mine disaster. When the fire occurred 410 men were underground. One main shaft, the Granite Mountain, was 3,740 feet in depth and had two main hoisting compartments, as well as a third compartment, separated from the others by a solid timber partition, with a man cage, air lines, water lines, and electric power lines; it had a downcast air current. The other main shaft, the Speculator, about 800 feet from the Granite Mountain, was about 3,000 feet in depth, equipped with cages, and connected by drifts or crosscuts to the Granite Mountain at the various levels. There were two subsidiary ventilation shafts, the Gem and the Rainbow, and various connections to other mines.

The North Butte mine was one of the best-ventilated mines in the Butte district. Two surface fans at the Gem and Rainbow shafts exhausted about 50,000 cubic feet of air per minute from the mine, and about 10,000 cubic feet of air per minute left the mine through the Speculator shaft, a natural upcast. A reversible fan at the collar of the Speculator shaft was not in operation when the fire started. These surface fans were augmented by a large number of auxiliary, electrically driven, underground fans with canvas pipe for carrying air to the faces. A large number of underground doors controlled the air currents.

Electricity was widely used underground for power, light, and the 15 trolley locomotives; practically every level had electric power available. Current at 2,300 volts potential was transmitted from the Granite Mountain shaft to a transformer station on the 2,600-foot level.

Just before the fire the North Butte Co. had started to pipe the shaft and place sprinklers in it to provide better fire protection. Small tanks were placed at intervals of a few hundred feet down the shaft to reduce and equalize the pressure. Plans had been made to move the main transformer station from the shaft at the 2,600-foot level back several hundred feet, partly as a fire-prevention measure. Preparatory to moving the transformer station at the 2,600 level, six men started to lower 1,200 feet of lead-armored cable into the shaft, this cable to be used in extending the main transmission line to the new station. The cable weighed 5 pounds per foot or 3 tons in all; it was lashed to a hoist rope by 4-foot lengths of hemp rope, placed every 10 feet for the first 500 feet and at 5-foot intervals thereafter. No clamps were used because of the possibility of crushing the cable. As the cable was about to be landed on the 2,600-foot level it slipped from its lashings and fell, lodging in the shaft between the 2,400 and 2,800 levels and breaking water pipes; in its fall, much of the lead armor was torn off, exposing and fraying the oil-impregnated cambric and jute insulation. Of the cross section of the cable, fully half was oil-impregnated, highly flammable material. The cable was ruined, and at 11:30 p. m. on June 8 the assistant foreman, a shift boss, and two shaft men went to just below the 2,400-foot level to try to

3 Harrington, D., Lessons From the Granite Mountain Shaft Fire, Butte: Bureau of Mines Bull. 188 1922, 50 pp.

A

attach the cable to the cage and pull it up. As the badly wrecked cable was being examined, the flame of a hand carbide lamp came in contact with the frayed, oil-soaked insulation, and a blaze started which forced these men to retire to the 2,400-foot station. They, with other men on the level, tried to extinguish the fire, but in a few minutes the shaft timbers had become sufficiently ignited to change the normal downcast in one compartment of the Granite Mountain shaft to an upcast, and smoke started to spread through both the upper and lower levels of the mine. Within 30 minutes smoke started to issue from the nearby upcast Speculator shaft; within 11⁄2 hours it had spread into two connecting mines. Various foremen and shift bosses rushed through the mine warning the men. number of the men escaped through three connecting mines; 3 groups of men bulkheaded themselves from the fire (2 of these groups were saved in part-25 out of 29 in one place and 6 out of 8 in another), and 32 men were taken up from the Speculator shaft to safety. One hundred and sixty-three of the 410 men in the mine perished, only 2 by direct contact with fire, and the others because of gases from the fire. Soon after the fire started, the Gem shaft fan was stopped to minimize the spread of gases through the mine. Shortly afterward fans at the Gem, Rainbow, and Speculator shafts were started as blowers, thus blowing approximately 100,000 cubic feet of fresh air per minute into the mine to clear the workings of fumes and force them up the Granite Mountain shaft. Eventually the fire in the Granite Mountain was curbed with water, care being taken to keep this shaft an upcast. Fans were installed underground to aid the rescue parties, and about 48 hours after the fire started suction fans were placed in operation over the Granite Mountain shaft.

Rescue work started almost immediately. Employees of the North Butte Mining Co. and the Anaconda Copper Mining Co. with oxygen breathing apparatus began immediately to assist live men to safety. A Bureau of Mines. rescue car and crew arrived from Red Lodge, Mont., the day after the fire began. Twelve hours after the start of the fire 50 oxygen breathing apparatus were available, and for several days at least 30 apparatus wearers were employed on each shift. On the second morning after the fire the recovery workers were augmented by a second Bureau of Mines rescue car from Colorado, making additional rescue apparatus available; in all, 92 sets of rescue apparatus were used. Forty-eight hours after the fire started the Speculator shaft had been freed of gases from the fire, the 2,400foot level had been cleared sufficiently of smoke so that 25 live men out of 29 had been recovered from behind the 2,471 bulkhead, and 80 bodies had been recovered. The recovery of 75 more bodies was difficult but was completed 8 days after the fire started. Several additional bodies were found afterward in cleaning up rock falls.

The following conclusions are derived from a study of this fire:

1. The upper end of an electric cable being lowered in a shaft should be firmly clamped, even if such clamping does ruin 8 or 10 feet of cable.

2. Electric cables in hoisting or ventilation shafts are a fire hazard, and boreholes should be used to bring such cables into a mine if practicable; if not, they preferably should be placed in upcast shafts or in shafts or shaft compartments that are as nearly fireproof as possible. 3. When a mine has two shafts, and the one downcast is afire and

filling the workings with smoke, efforts should be made by fans and other means to convert this shaft into an upcast.

4. The main hoisting, shaft of every deep mine should be fireproofed.

5. Connections between mines should be closed with airtight doors held closed by a positive latch that can be readily opened from either side in case of need.

6. To provide adequate ventilation and allow safe removal of men in case of disaster, every mine should have at least two fully equipped shafts from the surface to the lower stopping level. levels should be connected with both shafts.

All

7. Tight-fitting fire doors, preferably of fireproof construction, should be provided in every drift, crosscut, or other opening leading from any shaft. These doors should be of the self-closing type with a latch or other means of preventing opening (if kept normally closed) by reversal of the air current.

8. Direction signs in as many languages as needed to be understood by the mine personnel should be posted at suitable points, indicating plainly the direction of escapeways.

9. Timbered shafts should have ample facility for quick-action fire protection; and water lines for fire protection should be extended through mine workings, especially if much timber or other combustible matter is present.

10. There should be means for warning men promptly in an emergency.

11. Rescue apparatus is likely to be of great value in saving life and property if a serious mine fire occurs, such as that in the Granite Mountain shaft or the Argonaut shaft (described below). Men should be carefully trained to use such apparatus and to know its advantages and limitations.

ARGONAUT MINE FIRE, JACKSON, AMADOR COUNTY, CALIF.

4

A fire in the main shaft of the Argonaut mine in August 1922 killed 47 miners. This mine is a gold quartz property and at the time of the disaster employed about 165 men underground. It is worked through an inclined (57°) shaft that follows the dip of the vein 4,900 feet. The shaft has three compartments, each 4 feet by 5 feet, and is heavily timbered. Two compartments are used for skip hoisting; the manway contained a ladderway, a compressed-air line, a pump column, a high-tension cable, electric light wires, and signal and telephone lines. Levels are driven at approximately 150foot intervals. Ventilation was supplied through a second shaft 800 feet in depth and offset raises connecting to the lower levels of the mine. This ventilation-raise system was equipped with ladderways from the bottom level to the surface. At the collar of the ventilation shaft was a nonreversible fan exhausting about 40,000 cubic feet of air per minute from the mine. Wooden doors directed the air in the downcast Argonaut main shaft to the lower levels.

About 11 p. m. the shift boss and two skip tenders smelled smoke at the 4,200-foot level of the main downcast shaft and realized that there was a fire in the shaft above them. They had themselves hoisted to

Pickard, B. O., Lessons from the Fire in the Argonaut Mine: Bureau of Mines Tech. Paper 363, 1926,

the 3,000-foot station and found two timber sets burning on the hanging-wall side just below the station. One of these men remained at the 3,000 station to observe conditions; the other two went in the skip through the fire to the 2,000-foot level, where they telephoned to the hoisting engineer and then went to the surface to secure means of fighting the fire. Soon after their arrival the mine telephone, signal system, and lights went out of order. The 47 men below were cut off. Smoke began issuing from the ventilation shaft and soon was backing up the main shaft. Men equipped with oxygen breathing apparatus entered the skip and futilely attempted to combat the fire. Changes in the fan casing to allow reversal of the air current would have taken several hours and probably would have been useless, as doors in levels above the fire zone normally closed would have been pushed open by a reversal of the air current and short-circuited the air; the air current was not reversed during the fire fighting. Exploration or rescue work through the ventilation raises was impracticable because 4 to 5 hours would be required to climb back out of these raises, all in highly toxic air from the fire. Men wearing oxygen breathing apparatus controlled extension of the fire up the shaft by means of a high-pressure water line and hose and then put in an airtight bulkhead about 2,300 feet down the main shaft. It was possible to gain access to the lower levels of the Argonaut mine by reopening caved connections with the adjoining Kennedy mine and driving some 80 feet in solid rock; 21 days of the most arduous labor opened a way to the 4,200-foot level of the Argonaut mine. Another connection from the 3,900-foot level of the Kennedy mine was being driven simultaneously with the driving of that on the 3,600-foot level; the distance of 140 feet in solid rock; was not completed. Forty-six bodies were found on the 4,350-foot level behind a double bulkhead built of waste, boards, and clothing. Evidently gases had penetrated the bulkhead, and the men had died within a few hours after the fire. The forty-seventh body was found later on one of the levels below the 4,350.

Three possible causes for this fire have been advanced: (1) Electricity, (2) incendiarism, and (3) lighted cigarette or match inadvertently thrown to the hanging-wall sets. Most of the investigators believe that a short circuit in the 2,300-volt power line in the shaft caused the fire. The skip tender testified that during his observation the fire was spreading from about the location of the shaft wiring. The point of origin was near a cast-iron junction box, and the armor and outer insulation had to be removed from the cable to allow it to enter the ends of the box. On the day before the fire some decayed timber just below the 3,000 station chute had been replaced. The old timber, stored temporarily in the manway, may have been thrown against the power cable, jarring or displacing the wiring at the junction box. A short circuit in the junction box or in the cable itself could have ignited trash in the chute or the stored punky timber. After the fire there was evidence of arcing about the cable at the junction box. The power cable was made up of three smaller cables of 18 copper wires, each insulated with rubber and cotton fabric. The cable was encased in lead tubing, which was in turn armored, and the whole was protected from moisture by a covering of tarred hemp cord. A circuit breaker in the hoisting house was said to operate readily.

Advocates of incendiary origin of the fire pointed out that a previous fire in the mine had been proved of incendiary origin, that the fire