On a late summer’s evening 25 years ago, a disastrous fire destroyed the largest shovel on the planet. The event still lives vividly in the memories of those involved in that horrific event. The Marion 6360 stripping shovel known as “the Captain” was the flagship machine at the vast Captain mine complex near Cutler, Illinois. When originally put to work in 1965 by Southwestern Illinois Coal Corp., the machine made headlines with the technical press around the world.
At 180 yd3, the Captain shovel wielded the biggest dipper ever mounted on a shovel. It had two dipper doors, each weighing 15 tons. (Photo: Keith Haddock)
A masterpiece of American engineering, the Captain was commissioned on October 15, 1965. It was named after Thomas C. Mullins, known as Captain Mullins, a leader in surface coal mining technology in the early 20th century. His son, W.E. (Bill) Mullins, president of Southwestern, named the machine and the mine after his father. It doesn’t sound like much today, but it was said the Captain shovel cost $25 million in 1965, and went to work the same year Caesars Palace opened in Las Vegas, also at a cost of $25 million. In 1969, Southwestern was purchased by Arch Mineral Corp., which later became Arch Coal.
The gigantic shovel’s dimensions and specifications are hard to comprehend. Its operating weight, estimated to be some 15,000 tons, was more than double the weight of the Silver Spade (Bucyrus-Erie 1950-B, last operating stripping shovel at 105-yd3 capacity, weighing 7,200 tons). The Captain’s 215-ft boom rose more than 200 ft above ground, undercarriage width was 88 ft, and maximum dumping height was 153 ft. The 6360 shovel’s dipper measured 18 ft 6 in. wide, 24 ft 6 in. from front to rear and 16 ft high. It held 180 yd3 or 300 tons of rock and earth, and was the only shovel ever built with two dipper doors. They each weighed 15 tons.
Like most stripping shovels, the 6360 was mounted on eight crawler units assembled in pairs at each corner of the lower frame. Individual crawler assemblies measured 45 ft long, 16 ft high, and were fitted with 42 10-ft-wide shoes. Each shoe weighed 3.25 tons and, with eight crawlers, 336 were needed in total. At each corner of the lower frame, a giant vertical hydraulic cylinder 16 ft 9 in. high and 66 in. diameter supported the machine on the crawler assemblies.
Electrical equipment on board included eight hoist motors rated at 16,000 hp, eight swing motors provided 10,000 hp, and four crowd motors added another 4,000 hp. A total of 16 propel motors, one at each end of each crawler unit were rated at a total of 3,200 hp. Of course, not all these motors ran with maximum power at the same time, but the machine consumed enough electricity to serve a town of 30,000 people.
The Captain mine ran a three-shift operation with the afternoon shift running from 4 p.m. to midnight. The 6360 Captain shovel had a four-man crew consisting of operator, oiler, welder, and a ground man who looked after the trailing cable and operated a wheel loader to clear stray rocks around the machine. Gene Miller was the operator of the 6360 on the fateful afternoon shift of September 9, 1991. At about 7 p.m., he noticed a burning smell, stopped the machine, and went with oiler, Fred Kruger, to find where the smell was coming from. “That kind of smell could have come from a variety of sources,” Miller said. “It could have been a brake shoe sticking, overheated shaft bearing, or electrical fault, just to name a few. So we checked the house first and then noticed some smoke coming up from the lower works. On investigating, we found some hydraulic oil had caught fire in that area.”
Miller continued, “Oiler Fred Kruger, welder Gary Andrews and I immediately started to fight the fire with 20-lb dry chemical fire extinguishers. There were many dozens of 20-lb extinguishers positioned all over the machine. We started using these as fast as we could, but the fire seemed to increase rapidly and we were running out of extinguishers in that area. At that point, we realized we needed help, so I reported the fire to the mine office. Meanwhile, Gary went up the elevator to the roof to get some more extinguishers.”
The mine’s two small fire trucks were sent to the scene. They carried 200-lb dry chemical fire extinguishers, soon found to be of little use because the main fire was some 30 ft above ground. Access onto the machine was deemed unsafe because of the intense fire and smoke. Because of the rapidly increasing fire, the mine office also requested help from the Cutler Fire Protection District. Fire Chief Larry Bennett received the call at 9:44 p.m. He also called for assistance from other fire brigades, and before the night was over, brigades from local districts Pinckneyville, Percy, Campbell Hill, Steeleville, Coulterville, DuQuoin and Sparta had also joined the battle.
The fire on the night of September 9, 1991, that destroyed the Captain. The firefighting vehicles in the foreground are on a bench some 25 ft above the pit floor on which the shovel is standing. (Photo with special permission, Copyright 1992, J. Monroe)
Welder Gary Andrews continued the story, “I made three trips up the elevator to the roof to bring down fire extinguishers. By the time I went up for the third time, acrid smoke was filling the house. It was thick and black and you couldn’t see anything. What’s more, smoke was starting to come up the elevator shaft, so thick I couldn’t descend. By this time the other crew members had descended to the ground by the ladders. I was doing everything I could to save the machine. I waited a short time on the roof to see if the rough terrain crane with man basket that arrived on the scene could reach me. But it did not, and the roof got so hot I had to climb to the top of the gantry.”
Miller continued to describe the scene, “By now it was completely dark, and the welder on the roof was trapped. The electrical system had kicked out, and fortunately for him that didn’t happen when he was in the electrically powered elevator. And he couldn’t gain access down the house ladders or enter the house because of the intensity of smoke and heat. He was in a dangerous situation because there was a lot of combustible oil products on board the machine.” The hydraulic system, which caught fire first, contained 8,000 gallons of hydraulic fluid. There was also a 1,000-gallon diesel fuel tank, 1,000 lb of grease in the automatic grease system, and 1,000 gallons of solvent in drums.
For about the first half hour after the fire chief arrived, as he later reported, there was much confusion. Mine workers on shift frantically attempted to do things on their own, giving conflicting instructions to firefighters and lacking authority to obtain additional equipment as needed. In the panic, it was reported that one of the mine foremen drove off the coal seam in the dark and overturned his truck, but was not injured. Eventually, a command post was established in the Steeleville fire department’s emergency vehicle. In addition to the fire brigades’ vehicles, the mine contributed mobile water tankers, lifting equipment, and a boom truck with man basket.
The initial strategy was to set up a water supply and a deluge gun to try and cool the metal. An aerial ladder was set up, but this was not high enough to rescue Andrews on the roof who had retreated up the gantry to escape the smoke. Fire Chief Bennett later reported, “The fire was coming out all around the lower frame, some 30 ft off the ground. The fire looked like a very big gas stove burner with the largest pot you have ever seen sitting on it.”
Miller reported, “I was able to talk Gary into putting on a safety harness and snapping it onto one of the 2-in. boom suspension cables which run from the top of the gantry to the top of the boom. This he did, and then cautiously made his way to top of the boom by walking on one of the other cables. Of course, he had to temporarily unsnap the harness as he negotiated each of the stabilizer blocks separating the pairs of ropes. Once on top of the boom, some 21 stories skyward, he was able to walk down the boom steps until he could be reached by the man basket. He was then lifted to safety. Fred Kruger came up the boom to meet me. He was hoisted in the man basket to the lower part of the boom and then walked to the top. He came up to make sure I was alright after my ordeal climbing up the suspension rope, and he helped me down to safety.”
Miller recalled, “I stayed about three hours after my shift finished at midnight. The fire was almost out by 2 a.m., but the heat melted the seals in the swing gear cases, releasing the oil which fed the fire back to life. It burned for another three hours and was finally out by about 5 a.m.”
Miller described the scene the day after the fire when the Captain could be inspected in daylight. “Looking at the 6360 from a distance, it was hard to imagine the horrors and intensity of the fire the night before. Except for some blackened areas at the bottom of the house and some lower steel panels missing, the machine looked normal.” he said, “The lower works were definitely charred and blackened, but on climbing up into the machinery house and cab, everything appeared unaffected except for smoke residue.”
So at first inspection, it appeared the damage was confined to the lower works and a project was commenced to estimate the cost of repair. At the same time, a replacement machine was needed immediately to take over. The giant 6360 shovel worked in the same pit in tandem with the Bucyrus-Erie 5872-WX, world’s largest cross-pit bucket wheel excavator. Without the 6360, this 700-ft long, 5,380-ton monster, and a lot of other equipment including drills, parting shovels, coal loading shovels, trucks, loaders and dozers would soon run out of work. So it was vitally important to maintain overburden production.
Fortunately, Arch Mineral had a Marion 5900 stripping shovel parked at the nearby Leahy mine, which the company had taken over a few years earlier. Although much smaller at 105-yd3 capacity, it was the best thing available to take over. So even before damage estimates had been completed on the Captain shovel, Miller was assigned to lead a team to bring the 5900 back to life and prepare it for the walk to the Captain pit.
Then came disappointing news: A much closer inspection of the Captain’s damage revealed that the fire in the lower frame had burned furiously for many hours, feeding on hydraulic oil from the shovel’s leveling and steering systems that used giant hydraulic cylinders. The intense heat had weakened much of the structure, and worse, the main revolving frame revealed a huge crack in the 5-in. thick steel floor plate running from one side of the machine to the other. This was presumably caused by the firefighter’s water cannon spraying on the overheated metal.
An estimate for repairs valued at $7 million was received from Marion Power Shovel Co., but after close review, and given that a replacement machine had been found, Arch Coal decided to scrap the 6360 Captain shovel. A contract was awarded to United Salvage Co. of Illinois and the machine was scrapped in 1992. The 6360 was insured by Lloyds of London, and after review of insurance adjusters’ reports, Arch Mineral accepted a payment of $35 million for loss of the Captain.
Standing forlorn after the fire, the Captain shovel shows relatively little damage, but the lower works are gutted. The Marion 6360 sign peeling off the machine foretells the machine’s fate. (Photo: Eric C. Orlemann)
Miller added that the cause of the fire has never been exactly confirmed. “One theory was that oily rags in the hydraulic room caught fire from sparks from an electric motor. Another theory was that a leaking hydraulic hose caused an oily mist, which could have been ignited by motor sparks,” he explained.
As an operator, Miller praised the 6360 Captain shovel. “She was a wonderful machine; nothing could touch her when it came to production. When I was on her, we regularly dug a complete pit one mile long from end to end in only 10 days. We regularly turned in production numbers showing more than 7,000 cubic yards per hour,” Miller boasted proudly. “The east half of the pit, where the overburden reached 100 ft high, the Captain dug this in only five days. When we took over with the 5900 shovel, this same section took 11 days.” Production numbers obtained from Arch Mineral confirmed Miller’s experience. During her active life, the Captain shovel moved 809,300,000 cubic yards of overburden, a number far greater than any other single shovel or dragline.
The author sincerely thanks Arch Coal, and the following for their help and cooperation in the preparation of this article. Gene Miller, Captain shovel operator; Gary Andrews, Captain shovel welder; Steve Monroe, Arch Coal; Jim Gielow, fire chief, Pinckneyville Fire Department; Kim Link, previously with Arch Coal; and Eric C. Orlemann, author and photographer.
About the Author
Keith Haddock, P. Eng., F.C.I.M., is a freelance writer and former engineering manager for Luscar Ltd. in Canada, now part of Westmoreland Coal.