The Environmental Working Group posted a report last month about near-complete scientific studies that show "mine tailings from uranium mining along the Colorado River do not lead to contamination in the main river could undermine environmentalists' and other critics' opposition to Bush administration efforts to permit controversial proposed mines that they fear will contaminate the river."
However, after apparently posting the staff report on February 23, it was removed and the page (http://www.ewg.org/node/27650) says it is under development and not available.
EWG's press release said a University of Arizona researcher found that "much of the uranium in the river is naturally-occurring, a key indication that the industrial activity does not harm the water quality for drinking water and agricultural activity that depends on the river for water."
A copy of the EWG press release was forwarded to me with a note saying that the study is coming from the Water Sustainability Program at the UA. My source says the UA preliminary findings support the Kaibab Joint Venture Draft Environmental Assessment (http://public.dirxploration.fastmail.us/) conclusion that continued uranium exploration and mining in northern Arizona would not threaten Colorado River quality.
If all this information is correct, EWG is also correct in predicting it would have the big impact on actions to stop uranium exploration on federal lands in the region.
This is a developing story that is likely to get lots of attention in both the mining and environmental communities.