The gob pile, an abandoned mine dump, is the accumulation of waste products from an underground mine (fig. 12). The piles are known variously as gob piles, slate dumps, boney piles, and culm banks. The gob pile stands about 150 feet above the general land surface. Excellent plant fossils have been collected from the gob pile at this mine. A second large gob pile, located southeast of this stop on the east side
of the road, has been reclaimed. |
Photo: Ben Riegler
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Drone photo: Charles Nicchia
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The gob pile was created by dumping unwanted rocks that were removed from the mine. The early mining methods were labor intensive. Coal miners dug several inches of underclay by hand from under the coal seam so they could break the coal down and out from what is called the working face. In addition, along their haulage ways, they dug out rock above the coal to make a high tunnel so that mules pulling the mine cars could walk through. Rock that fell and sagged into the haulage ways had to be removed to keep them open. The waste rock that could not be stowed in the underground openings left after the coal was mined was brought to the surface and dumped on the pile.
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These gob piles contain iron pyrite, sometimes called “fool’s gold” because of its yellow metallic luster. Pyrite is iron sulfide, which is stable buried beneath the earth surface. When exposed to water and oxygen, however, pyrite oxidizes and produces sulfuric acid, iron oxides, and hydroxides. The iron oxides and hydroxides, which are similar to common rust, tint these gob piles red. Sulfuric acid, however, pollutes both the water and the soil around the mines.
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Excavating for siderite concretions.
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Exploring the slopes of Red Dog Shale.
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Less common are the plates of “blistered” black shale. The miners called this rock “slate,” perhaps because it is hard and splits into smooth sheets. The black shale generally lies on top of the gray shale above the Herrin Coal. Sometimes, however, the black shale is close enough to the coal to be taken down when heightening the haulage ways. Strewn over the slopes are dark gray and brown ironstone nodules—heavy for their sizes— which were formed in the gray shale above the coal.
Of course, there are a few pieces of coal on the pile. |
Header image: The Danville area shaft mine spoil as seen from a nearby road. Photo: Rich Holm.
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Copyright © 2020 Andrew Young. All rights reserved.
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