Patrick Wales, a Project Manager with Virginia Uranium, Inc., shows an exploration drill hole at Coles Hill Farm, about 6 miles east of Chatham, Va. (Tracy A. Woodward/THE WASHINGTON POST)

Fairfax County Water Authority’s board of directors has released a study it commissioned on the impact that uranium mining could have on its watersheds.

The study, prepared by two Fairfax firms, Tetra Tech, Inc. and Hazen and Sawyer, comes on the heels of a 22-month review by the National Academy of Sciences and National Academy of Engineering. The academies’ review, released earlier this month, found that “steep hurdles” need to be surmounted before Virginia’s longtime ban on uranium mining could be lifted.

A study commissioned by the Danville Regional Foundation also came out this month. It concluded that uranium mining could have economic benefits but also environmental risks.

The upshot of the Fairfax study:

“[U]ranium mining and milling represent unique risks that require additional process controls to prevent impacts from toxic and radioactive byproducts.

“Uranium mining and milling activities initiated in the Potomac and/or Occoquan watersheds have the potential to increase the risk of negative impacts to Fairfax Water’s source water quality and water supply reliability. The likelihood and magnitude of such impacts would depend to a large extent on facility design, operational characteristics, and standards that would ultimately be determined during the regulatory and permitting process.”

The study calls for a “conservative and precautionary approach” to mining.

You can read the entire 132-page study here.