… Out the back of the machine, like the tail of a four-thousand ton rat, ran a huge black cable, through gully and gulch, over hill and draw, to the generating plant — whose No. 1 customer was the big machine.
This is from Annals of the Former World by John McPhee (1998). This book is a combination of what was originally four separate books; today’s extracts are from what was Rising from the Plains (1986):
… This was Jim Bridger, a coal-fired steam electric plant, built in the middle nineteen-seventies, with a generating capacity of two million kilowatts — four times what is needed to meet the demands of Wyoming. Twenty-four stories high, the big building was more than twice as tall as the Federal Center in Cheyenne, which is higher than Wyoming’s capital dome. Rising beside the generating plant were four freestanding columnar chimneys so tall that they were obscured in cumulus from the cooling towers, which swirled and billowed and from time to time parted to reveal the summits of the chimneys, five hundred feet in the air.
… The idea behind the Jim Bridger was to ship energy out of Wyoming in wires instead of railway gondolas. Ballerina towers, with electric drapery on their outstretched arms, ran from point to point to the end of perspective, relieving pressure on the Oregon-Idaho grid. The coal was in the Fort Union formation — in a sense, the bottom layer of modern time. [ … ] As the mountains themselves became buried, the fallen vegetation in the thickening basins was ever more covered as well, to depths and pressures that caused it to become a soft and flaky sub-bituminous low-rent grade of coal, a nonetheless combustible low-sulphur coal. With the Exhumation of the Rockies, nature, in the form of wind and water, worked its way down toward this coal. By the middle nineteen-seventies, nature had removed a mile of overburden, and had only sixty feet to go. At that point, something called the Marion 8200, and eight-million-pound landship also known as a walking dragline, took over the job.
The machine was so big it had to be assembled on the site — a procedure that required fourteen months. Now working within a mile or two of the generating plant, it could swing its four-chord deep-section boom and touch any spot in six acres, its bucket biting, typically, a hundred tons of rock and dumping it to one side. The 8200 had dug a box canyon, its walls of solid coal and about thirty feet thick. The inside of the machine was painted Navy gray, and had non-skid deck surfaces, thick steel bulkheads, handrails, and oval doors that looked watertight. They led from compartment to compartment, and eventually into the air-conditioned sanctum of Centralized Power Control, where, lined up in racks, were electric motors. The foremost irony of this machine was that it was far too large and powerful to operate on diesel engines. Although the chassis was nine stories high, it could not begin to contain enough diesels to make the machine work. Only electric motors are compact enough. Out the back of the machine, like the tail of a four-thousand ton rat, ran a huge black cable, through gully and gulch, over hill and draw, to the generating plant — whose No. 1 customer was the big machine.
Once every couple of hours, the 8200 walked — raised itself upon its pontoonlike shoes and awkwardly lurched backward seven feet, so traumatically compressing the dirt it landed on that smoke squirted out the sides and the ground became instant slate. This machine — with its crowned splines, its precise driveline mating, its shop-lapped helical gears, its ball-swivel mounting of the boompoint sheaves, its anti-tightline devices and walking-shoe position indicators — had unsurprisingly attracted the attention of Russian engineers, who came in a large committee to see Jim Bridger, because they were about to build twenty-five similar generating stations in one relatively concentrated ares of Siberia, which they confided, closely resembled Sweetwater County, Wyoming.
This strip mine, no less than an erupting volcano, was a point in the world where geologic time and human time overtly commingled. Ordinarily, the close relationship between the two is masked: human time, full of beepers and board meetings, sirens and Senate caucuses, all happening in microtemporal units that physicists call picoseconds; geologic time, with its forty-six hundred million hears, delivering a message that living creatures prefer to return unopened to the sender. In this place, though, geology had come up out of its depths to join the present world, and, as Love would put it, all hell had broken loose. “How people look at it depends on whose ox is being gored,” he said. “If you’re in a brownout, you think it’s great. If you’re downwind, you don’t. Wyoming’s ox is being gored.”
The biggest rat of all is the German Bagger 288; “The excavator is up to 220 m (721 ft) long and approximately 96 m (315 ft) high. The Bagger’s operation requires 16.56 megawatts of externally supplied electricity.” [Wikipedia]
Bagger 288 [image from Wikipedia]