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Show could easily end up in surface- - and groundwaters as a result of leaching and erosion, both of which are inevitable given the extremely large quantities of spent shale. Second, oil shale mining in Colorado will require pumping and disposal of large quantities of saline groundwater for the mining to proceed. We have seen no disposal plans certain to avoid salinity hazards." May contain toxins Utah's White River provides a green oasis in a desert rich in oil shale, indicated by the dark striations throughout the cliffs. A major source of future petro- - leum, oil shale tracts are to be developed here and in Colorado, but doubts exist about the impact of large- scale mining on both regions' air, water and wildlife. Two years ago, in its draft environmental impact statement, a federal panel warned: "Leachate or runoff from spent shale could contain potentially carcinogenic polycyclic aromatic hydrocarbons PAH) as well as toxic trace metals such as cadmium, lead, mercury, molybdenum and selenium." Occidental believes it has the answer to the problem of spent shale; it's called processing. (meaning Instead of mining the rock and hauling it to a retort on the surface, the oil is extracted underground. On Aug. 30, Secretary of the Interior Cecil Andrus to gave the company the in federal a tract the to process apply the Piceance Creek Basin on which Occidental holds a joint lease with Ashland Oil. Two days later, ground-clearin- g ), work began on Colorado-- b tracts the governone of two 5000-acr- e ment has leased to oil companies and the first on which development has been approved. Development on two tracts in Utah has been held up by legal disputes. The process to be used on tract C-- b is similar to the one I observed beneath Mt. Logan. After geologists have determined the best shale beds, they will be divided into what miners call rooms, 200 feet square and 310 feet high. Natural rock pillars will be left to provide support between the rooms, and tunnels will be built to allow access. in-si- tu lire J Mil Mil by Peter DE BEQUE, COL. country has the greatest petroleum reserves in the world? hich : ' ; . .' r f ; Saudi Arabia? Iran? Actually, the U.S. has potentially more petroleum than the rest of the world combined. There's one problem: it is locked in rock, oil shale. During the Eocene Epoch, which ended about 40 million years ago, this part of northwestern Colorado was under a body of water geologists have since dubbed Lake Uinta. Organic matter, mostly algae, settled to the bottom and was compacted by mineral silt over a period of 20 million years. When the water receded, it left behind fossil remains estimated to contain 1.8 trillion barrels of oil. A third of that amount, 600 billion barrels, is considered commercial grade which approximates the world's underground oil reserves. At the turn of the century, there were some 200 shale mines in Colorado; and in 1917, just a few miles northeast of retort here, the first above-groun- d b'dgan separating oil from rock Yet the nascent oil shale industry was nipped m the bud. Why? "In a word, economics," said Henry O Ash, the chairman of the Interior Department's Oil Shale Environmental Advisory Panel. "It's been the principal harrier to oil shale development for the past 50 years. Just as it was getting started here in Colorado, new supplies obcheap commercial crude oil) came J. Me Ognibene the 1920's." Now, with those Texas oil fields and other domestic sources approaching exhaustion, interest in oil shale has been revived. The richest deposits are in Colorado's Piceance Creek Basin, a area near here. When oil shale is heated at 900F, a fossil fuel called kerogen is released. On Mt. Logan, near De BeqUe, Occidental Petroleum has been producing shale oil for several years and has found it to be of high quality, though the quantities so far have been small in East Texas in Used as fuel oil "We sold 5000 barrels of shale oil to Consumers Power of Michigan," Occidental's Marney Talbert told us, "and they burned it just as they would fuel generate electricity." If the principal obstacle to develop- oil to ing oil shale in the past was economic, now it seems to be concern for the environment. No one knows what impact large-scal- e development might have on the air, water and wildlife here, but environmentalists fear that an attitude could turn this starkly beautiful region into "a national sacrifice area." The lowest commercial grade of oil shale produces about a half a barrel of kerogen for every ton of shale; the better grades run about a barrel a ton. Thus for every barrel of oil, you wind up with one to two tons of spent shale. Looking ahead a decade or two, some energy industrialists foresee Colorado producing up to 2 million barrels of shale oil a day. What would be done with the veritable mountain of waste rock left behind? That question is very much in the mind of Carolyn R. Johnson, ex -- chairman of the Colorado Open Space Council's Mining Workshop. "Oil shale development," she said, "poses severe salinity threats which may create problems of a much larger magnitude than those from water consumption alone. First, the waste shale material is extremely high in soluble salts, which energy-at-any-co- st e) go-ahe- (C-b- Rock exploded, burned After some 30 to 40 feet of shale at the bottom has been removed, holes will be drilled in the remaining rock and filled with explosives. When they are detonated, the solid shale will be reduced to rubble, filling the void at the bottom and transferring the empty space to the top of the room. Engineers put pipes into the top of each room to carry fuel, air and steam and install heat probes and other instruments. After the room is sealed, a fire is ignited at the top; air and steam are used to regulate the temperature and to keep the flame front moving downward through the rubble. The kerogen or shale oil flows out through pipes at the bottom; a gas which is produced as a is recovered separately and used to sustain the flame front as well as power electric generators. Another water vapor, is condensed, recycled and converted to steam to control combustion in the room. Exhaust gases are passed through "scrubbers" to cut air pollutants. Rock is blown to bits, heated, the oil extracted all in underground retort. continued |