John Lancaster's excellent "Frontier Legacy: Mining Public Lands" {Aug. 7} effectively describes the hazards of hard-rock mining in Nevada. Readers might be interested to know that uranium mining also falls under the archaic 1872 General Mining Law and, like hard-rock mining, presents a variety of environmental problems.

As the article points out, one of the problems is that the U.S. Forest Service and Bureau of Land Management take the position that they are prohibited by the 1872 law from turning down requests for mining permits on environmental grounds, however devasting the environmental consequences may appear or prove to be. Often, the result is further destruction of environments already heavily damaged by mining.

In the case of uranium, an example of what seems a callous application of the law is apparent in northern Arizona, an area that has been extensively mined for uranium over the past 40 years, and where it is estimated that tons of hazardous wastes have been dumped or washed into many of the streams that flow into the Colorado River. The Colorado River supplies water to huge populations in central Arizona and California. Yet, despite the acknowledged hazardous nature of uranium ore and its wastes, no baseline studies of Colorado River water have been done to determine the cumulative effects of the mines and milling, if any, on the water, sediments, fish and other aquatic life of the river. Indeed, today in this same area it is "business as usual" and more uranium mines are being proposed and developed on lands under the control of the U.S. Forest Service on the north and south rims of the Grand Canyon.

Requests for a comprehensive study of the cumulative regional impacts of uranium mining within the Colorado River watershed by the Havasupai Tribe, who live at the bottom of Grand Canyon, and several environmental groups have been brushed aside. It seems a reasonable request in view of the risks. In the interest of the public good, a change in the 1872 mining law for the protection of human health is long overdue. MARY G. BYLER Washington The writer works for a lobbying firm that represents the Havasupai Tribe.