First, the pile is situated on the outer bend of a meander of the Colorado River, almost immediately adjacent to the stream. In introductory geology classes we learn that outer meander bends undergo erosion.

Mr. De Nevers seems to argue that the entire town of Moab would have to be inundated in a "mega-flood" in order for the pile to be washed away. In fact, it may only take episodic high flows and natural wandering of the Colorado River to undercut the tailings pile. Folks in southwestern Utah recently learned the unfortunate consequences of high stream flows.

Second, the "1,000 tons" of uranium in the pile are not necessarily "practically insoluble." We know from the fundamental geochemistry of uranium that under oxidizing conditions, uranium is, in fact, relatively soluble.

Donald Langmuir's text Environmental Aqueous Geochemistry refers to uranium as "highly soluble" in oxidizing surface and ground waters. And, in fact, uranium is deliberately oxidized during the milling process in order to enhance its solubility, and, hence, its recoverability.

Finally, wells constructed in and around the tailings pile bespeak the unsuitability of the pile's present location. River gravels are present beneath the pile, as well as in the subsurface to the north and east. If the riverbed has been at the present location of the pile before, it will undoubtedly return.

Across from the pile on the other side of the river in the Matheson Wetlands preserve, radiocarbon-dated material with an age of 910 years appears at a depth of about 30 feet. Not surprising to this geologist, these test borings indicate that the Colorado River is in an ever-changing state of flux with respect to erosion, deposition and the position of its channel.

These observations alone should disqualify a plan to maintain the tailings in their present location.

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Steve Nelson teaches in the department of geology at Brigham Young University and is vice chairman of the Utah Radiation Control Board.