Strip-mining at Colstrip, Montana
n 1882 the Fort Union Formation's coal resources were rediscovered, this time by competent geologists who soon realized that it is the largest lignite-bearing geological formation in North America. Mining began somethat tentatively only three years later, primarily for local heating purposes. Steam locomotives, originally designed to burn wood, were retrofitted in the mid-1890s to burn coal, and the deep mines near the town of Red Lodge, Montana filled the new need. Soon after the turn of the twentieth century, the same mines provided coal to fire generators that produced electricity. By 1924 steadily increasing rail traffic through the Northwest demanded more efficient coal extraction techniques, and strip-mining began at a place called Colstrip (see map
Eighteenth-century mining for pit-coal had left comparatively minor scars on the landscape. But strip-mining in the mid-twentieth century literally laid waste to thousands of acres of formerly productive land. The overburden .the soil and gravel built up over millions of years .was scraped off the coal veins, shoved aside, and left in long, steep, parallel ridges. The coal was removed, and the whole mess, pits and piles together, was eventually abandoned.
Because the process was purely extractive, without regard for the structure of the overburden, there is little or no hope of restoring it simply by leveling it off and planting grass and trees. Only in due time, thousands of years-worth of time, will natural processes prove able to restore the land to anything like its original condition. The photo above is an aerial view of some Colstrip leftovers from the thirties, seen also at extreme left in the photo below.
Since the mid-1970s, strip-miners in Montana, as well as in other states, are required by law to remove overburden in an orderly manner, to refill the pits after mining the coal, restoring the overburden as nearly as possible to its original condition, and to replant it with the original types of vegetation. "The art and science of mine reclamation are now so highly developed," say geologists David Alt and Donald Hyndman, "that the recently worked sites are visible only to a knowing and practiced eye."1 Proof of that may clearly be seen in the smooth prairies surrounding the pit in the above photo.
Some of the lignite mined here at Colstrip is used to generate electricity at the plant in the upper center. The rest is shipped to coal-fired generators in other parts of the country, via 100-car "unit" trains.
David Alt and Donald Hyndman, Roadside Geology of Montana
(Missoula, Montana: Mountain Press, 1986), p. 223.