"Caverns Yawn As Big Muskie Bites"
Originally published: Athens Magazine, Fall 1982
Written by::Lee Earhart
Photograph by::Karen Nelson
We must have been a couple of miles away when I first caught glimpse of Big Muskie, the worlds largest dragline, a machine designed to remove soil from the pit in front of it. I could only see the top of its boom jutting above the ridge, but I could still tell it was a mighty big machine. And, as the car came to a stop in its shadow, I knew I was right. Maybe Im too sentimental, but theres something humbling about seeing a chain link thats big enough for me to walk through.
In 1952, the Central Ohio Coal Company began stripping the Meigs Creek No.9 seam near Cumberland, in Muskingum county. They contracted with the Ohio Power Company to supply coal to its generating plant at Beverly, on the Muskingum River. But in the mid 60s the Beverly plant was expanded, and Central Ohio could not supply the new demand.
So in 1965 they went to the Bucyrus-Erie Company of South Milwaukee for help. What was needed was a new machine - something bigger, that could remove more overburden and expose the coal faster. And it had to be able top dig close to 200 feet into the ground, reaching the deeper parts of the seam.
It took the engineers two years just to draw up the plans for the new machine. Something that big had never been attempted before. But in 1967 they were ready to start building.
Two years and 300,00 man hours later, the Big Muskie, the worlds largest mobile land machine, was standing.
Its overall width is 151 feet, or about the size of an eight lane highway. At the tip of the boom it stands 32 stories. It weighs 27 million pounds, as much as 13,500 automobiles or 128 Boeing 727 jets. Its bucket holds 220 cubic yards of earth, big enough to hold 12 cars, and weighs 240 tons. It can dig a pit 185 feet deep, as deep as Lake Erie. In one movement it can dump the overburden two city blocks away. And, all of this is controlled by just one man.
Because of its vast size, the Big Muskie could not be assembled in South Milwaukee. Instead, it had to be shipped in parts to the mine site for assemblement on a specially reinforced concrete launching pad. It took 350 railroad cars and 160 trucks just to transport all the pieces.
The dragline rests on a circular base, 105 feet in diameter. It was shipped to the site in 33 pieces, each weighing from 52 to 80 tons. These units were then welded together. The frame, made of 57 parts itself, revolves on this base atop 128 roller bearings, each 22 inches in diameter.
In order to move this colossal machine after it was built, Bucyrus-Erie engineers developed a new system. They came up with a way to walk the Big Muskie. Two shoes, each 65 by 20 feet, are located on either side of the frame. Four massive hydraulic cylinders, each bigger than a man, raise the entire machine off the ground. These cylinders can raise those 29 million pounds about 18 inches. Transverse pistons then push the frame backwards on the shoes. The shoes are raised, pushed forward by the pistons, lowered, and the process begins again. Like a dinosaur, the Big Muskie trudges 14 feet with each step.
Central Ohio was forced to develop new mining procedures to accommodate its new machine. Because of its size, the Big Muskie needs a level bench from which to dig, otherwise something cracks when it squats down. Often, through hours of digging, it made the bench itself, cutting drastically into its efficiency. So engineers devised the haulback system. With smaller equipment working ahead of it removing hills and filling in ravines, the Big Muskie is now free to remove only overburden.
Today the Big Muskie, with the help of a few structural changes and new mining procedures, works over 70 percent of the time, 24 hours a day, year round except for Christmas day. It removes approximately three million cubic yards of overburden a month. Operators are so adept at handling the monster that they can get within inches of the coal seam. "Thats what we call being close enough to strike a match," said Updyke.
As we left the mine, I turned around and watched the blue and grey waves of raw earth disappear behind us. In the distance I could see another dragline working, barely visible in a huge cloud of red dust, stripping away red clay.