FATAL AND NONFATAL INJURIES

In these decades injuries from all causes declined from 11,375 to 8,772 (table 1).

The injury-frequency trend from hoisting at underground mines (fig. 1) was downward, with a decrease of 27.9 percent, during 193251. During this 20-year period there were 208 fatal and 3,430 nonfatal injuries (total, 3,638) or 1.8 percent of the total injuries from all

causes.

During 1947-51 the trend was also downward, with a decrease of 25.7 percent in injuries. During this 5-year period there were 34 fatal and 643 nonfatal injuries (total, 677) or 1.8 percent of the total injuries from all causes (table 1).

TABLE 1.—Injuries from hoisting at underground metal and
nonmetallic mines, 1932-51 and 19521

[Prepared by the Branch of Accident Analyses, Division of Safety]

FIGURE 3.-Injury-Frequency Trend From Haulage at Opencut Metal and Nonmetallic Mines, 1932-51.

The injuries (fatal and nonfatal) from haulage at underground mines have declined from an average of 1,104 a year between 1932 and 1941 to 948 a year between 1942 and 1951. In these decades injuries from all causes declined from 11,375 to 8,772 (table 2).

The injury-frequency trend from haulage at underground mines (fig. 2) was downward, with a decrease of 10.2 percent, during 193251. During this 20-year period there were 249 fatal and 20,268 nonfatal injuries (total, 20,517), which is 10.2 percent of the total injuries from all causes (table 2).

TABLE 2.-Injuries from haulage at underground metal and nonmetallic mines, 1932-51 and 19521

[Prepared by the Branch of Accident Analyses, Division of Safety]

The injuries (fatal and nonfatal) from haulage at opencut metal and nonmetallic mines have increased from an average of 54 a year between 1932 and 1941 to 97 a year between 1942 and 1951. In these decades injuries from all causes increased from 665 to 1,008 (table 3). The injury-frequency trend from haulage at opencut mines (fig. 3) was upward, with an increase of 153.0 percent, during 1932–51. During this 20-year period there were 71 fatal and 1,446 nonfatal injuries (total, 1,517), which is 9.1 percent of the total injuries from all causes.

During 1947-51 the trend was downward, with a decrease of 12.4 percent in injuries. There were, during this 5-year period, 18 fatal and 373 nonfatal injuries (total, 391), or 8.5 percent of the total injuries from all causes (table 3).

TABLE 3.-Injuries from haulage at opencut metal and nonmetallic mines, 1932-51 and 19521

[Prepared by the Branch of Accident Analyses, Division of Safety]

3

A review of injuries from hoisting and haulage in the iron-ore mines of the Lake Superior district for 1944-52 attributes the injuries from cages, skips, and buckets to hoisting and those from locomotives, motor, cars, trucks, and belts to haulage. The hoisting summary revealed that there were 1 fatal and 16 nonfatal injuries (total, 17) or approximately 0.2 percent of the total injuries from all causes. These 17 injuries resulted in a time charge of 7,964 days or 0.5 percent of the total days charged from all causes. The haulage summary showed that there were 33 fatal and 609 nonfatal injuries (total, 642) or approximately 7.4 percent of the total injuries from all causes. These 642 injuries resulted in a time charge of 257,288 days or 17.0 percent of the total days charged to injuries from all causes. Sixteen of the fatal and 356 of the nonfatal injuries occurred in underground mines. where approximately 55.5 percent of the men are employed (13-year average).

3 Cash, Frank E., Accident Experience, Iron-Ore Mines, Lake Superior District; Bureau of Mines Inf. Circ. 7410, 1947, 11 pp.; and Inf. Circ. 7510, 1949, 16 pp. Review of Accidents in the Lake Superior District: Proc. Lake Superior Mines Safety Council, 1944, pp. 29-50; 1945-46, pp. 82-104; 1947, pp. 18-31; 1948, pp. 33-44; 1949, pp. 21-34; 1950, pp. 16-30; 1951, pp. 90-107; 1952, pp. 150-164; 1953, pp. 121-137.

HOISTING

Hoisting in underground metal and nonmetallic mines may be in vertical shafts, inclined shafts, or slopes and in opencut mines on inclined planes. Each method presents both similar and individual hazards.

HOISTING ACCIDENTS

The principal causes of hoisting accidents resulting in personal injuries are: Using equipment designed primarily to handle ore or rock to transport men; using makeshift equipment without proper controls and safeguards; and unsafe practices.

From 1869 to 1954 there were at least 10 hoisting disasters (5 or more fatalities) in metal mines, resulting in 80 fatal injuries; 8 of them took place in shafts and 1 each on an inclined plane and in a slope. They occurred in Alabama, Arizona, California, Colorado, Idaho, Michigan, and Montana at copper, gold, iron-ore, lead, and zinc mines.

Two of these disasters are described:

1. Leonard Mines, Montana, 1913-5 Killed

The engineer started to lower the east cage from the surface to the 60-foot level, using the hoisting-engine brake with the reel unclutched; it is believed that the rod connecting the steam brake-operating device with the controlling lever broke, and the brake failed to grip. The loose reel gained such speed that, when the engineer attempted to stop it by throwing in the clutch, the latter broke, and the reel continued to accelerate until it burst. Flying pieces broke the the connections on the west brake, and the west cage at the 1,400-foot level began to drop just as the east cage crashed past. Four men on the east cage were killed instantly when the cage hit the shaft bulkhead at the 2,200 foot level. The bursting reel wrecked the hoist room, and one man at the surface was killed by flying fragments. Eight men on the west cage were injured seriously, but, remarkably enough, none were killed.

2. Morning Mine, Idaho, 1936-10 Killed

Ten men were killed when a man-cage fell 900 feet. Immediately before the accident, 5 men, including the cager, entered the lower deck of the 2-deck cage at the 3,450-foot level. They were hoisted to the 3,050-foot level to complete loading on both decks. The cager permitted 6 men to get on the lower deck, making a total of 10 men. The cage doors were then closed and fastened. The engineer was signaled, and the cage was lowered until the upper deck was flush with the station floor. While the cager was opening the cage doors to the upper deck, the rope broke about 1,200 feet above the cage. No evidence was on the cage guides to indicate that the safety cams contacted them. The cage was used exclusively for hoisting and lowering men and material.

4

The report on Failure of Hoisting Rope at Paymaster Consolidated Mines, Ltd., Ontario, Canada, February 2, 1945, is given in the Appendix.

The following typical hoisting accidents are discussed briefly, and many other examples could be given from occurrences in recent years

4 Harrington, D., and East, J. R., Jr., Safe Practices in Mine Hoisting: Bureau of Mines Miners' Circ. 61, 1946, pp. 49-55.

that would cover other types of accidents and injuries from less

common causes.

1. A foreman was killed while he and a helper were being hoisted from a level where they had unloaded a storage-battery locomotive. Soon after the cage started a jar was felt, and tension was caused on the hoisting cable by an auxiliary set of lugs under the cage becoming entangled with the chairs, which had not fallen back as the cage was lifted. The tangle suddenly let go, and the cage was jerked some distance up the shaft. Both men were thrown against the roof of the cage, and the foreman fell off and down the shaft.

In this accident the chairs were not in good working order, and the doors on the cage may not have been closed.

2. A miner with a lacerated hand was being hoisted to the surface in a bucket to receive first-aid treatment. On the way to the surface he fainted

and fell 320 feet to the bottom of the shaft. The injured man should have been held in the bucket by another person. No injured person should leave a mine unaccompanied, even if the injury is a minor one.

3. A mine laborer riding in a small skip on a 40° inclined shaft raised up and was killed when his head struck a timber in the hanging wall of the shaft.

The laborer did not use the necessary precaution while traveling in skips on inclines; however, any type of conveyance is hazardous when it is possible to be killed or injured by a small change of position. A safe conveyance should be used.

4. A miner attempted to alight from a cage at a station in a vertical shaft after the signal had been given to lower the cage to another level and the cage had started to move. He was pinned between the station floor and the top of the cage, receiving fatal injuries. The station gates were closed, but it had become customary to leave the cage gates open.

The gates were put on the cage to keep men from accidentally or deliberately exposing themselves to risks of this nature, but the safeguards were not used, and the man's actions were reckless enough to cause his death.

5. An experienced skip tender got into his usual place on the padded, clamped loop of the hoisting rope with his feet on the bail of a skip operating in a shaft inclined at 22°. He pulled the bell cord, and after the skip had moved about 20 feet he fell off onto the rail and was killed by the skip before it could be stopped by the foreman, who was riding inside.

This is another example of unsafe procedure in use of skips for handling men.

6. A skip tender completed loading an ore skip at a loading pocket and gave the signal to hoist. The engineer was oiling and adjusting the hoist and did not raise the skip for several minutes. When the hoist started, the engineer felt a jar after the skip had gone a few feet. He stopped the hoist; on investigation, it was found that the skip tender had been caught by the skip and instantly killed. The skip tender had evidently left his compartment and stepped onto the skip while it was waiting.

This is an example of a skip tender taking a chance; such accidents can be avoided only by training employees in safe methods of work.

7. A motorman and his car loader were being lowered in a 1-ton man and supply skip suspended beneath an ore skip by a 13-foot length of 1-inch steel cable which was fastened by 3 clips and a thimble at each end. The shaft was inclined 65°. The supply skip hung up or got off the track and then was released, and fell the length of the attaching cable. The jerk pulled the dead end of the cable through the clips, and the men were killed when the supply skip smashed against timbers several hundred feet lower.

Investigation revealed that the clips were securely fastened; and even if they had been, the number of clips used probably was inadequate to withstand the force of such a jerk.

8. A cager and a shift boss got on a cage at a level in a vertical shaft. The cager was carrying three pieces of drill steel. When the cage was lifted the lever operating the chains attached to the cage struck the drill steel, causing one length to project over the edge of the cage. This steel caught under a