JUNEAU, Alaska (AP) — The possible failure of a dam holding waste from a large-scale mine near the headwaters of one of the world's premier salmon fisheries in Alaska could wipe out or degrade rivers and streams in the region for decades, the U.S. Environmental Protection Agency said in a draft watershed assessment released Friday.
EPA regional administrator Dennis McLerran said there was a fairly low risk of that occurring, however, and the more likely impact would be direct loss of habitat from the mining activity itself.
The report responded to concerns about a large copper-and-gold prospect near the headwaters of Bristol Bay. It is a draft, with a final report that could affect permitting decisions perhaps due by the end of the year after public comment and peer review.
The Pebble Partnership, the group behind the Pebble Mine project, has called the deposit one of the largest of its kind in the world, with the potential of producing 80.6 billion pounds of copper, 107.4 million ounces of gold and 5.6 billion pounds of molybdenum over decades.
It has been the subject of a heated public relations battle for years. Supporters say it would bring much-needed jobs to economically depressed rural Alaska, but opponents fear it could fundamentally change the landscape and disrupt, if not destroy, a way of life.
McLerran told reporters the study is not about a single project such as Pebble but instead is a look at the potential impacts of mining in a region that he says accounts for 46 percent of wild sockeye salmon worldwide. He said there are at least seven other claims in advance stages of exploration and development.
The report said that if water from a mine is not managed, contaminants would flow into streams. Even without any failures, the agency said there would still be an impact on fish due to eliminated or blocked streams, removal of wetlands and a reduction in the amount and quality of fish habitat as water is used for mine operations.
It offered no verdict on whether the Pebble Mine project should move forward.
The report is not an in-depth assessment of any specific mine but rather is billed as a look at the impacts of the kind of mining needed to successfully develop the deposit.
It is based on a hypothetical mine scenario that the agency says draws in part on plans and data put forth by the Pebble Partnership.
Therefore, EPA acknowledges, it may not mirror the location and size of things such as a mine pit or tailings storage facility.
Due to lack to quantitative information on salmon, char and trout populations, the review could not quantify such things as the consequences of habitat degradation or loss on fish populations.
Pebble Partnership CEO John Shively in a statement called EPA's review rushed and inadequate and said he was concerned it could be used as a basis for "unprecedented" regulatory action against the Pebble Project. He said Pebble spent years studying a much smaller area around the deposit while the EPA, with what he called limited time and resources, covered an area of about 20,000 square miles.
He said Pebble is working on an environmental mitigation plan intended to protect fish and water in the area. He couldn't say when that might be presented. "We are working on it but our position has been that we need to get this right, because we're in a sensitive area," he said in an interview.
EPA's assessment put the annual probability of failure for a tailings dam — the kind that could destroy more than 18 miles of salmon stream and degrade the habitat of more streams and rivers for decades — in the range of 1-in-10,000 for a project designed, built and operated using standard engineering practices, to 1-in-one million for a state-of-the-art operation.
The failures evaluated are those that EPA said have occurred at other large-scale mining projects and could occur during operations or after the mine is closed.
Alaska Attorney General Michael Geraghty had fought EPA over the study, calling the agency's actions premature and an overreach — positions echoed by Pebble Partnership.
Geraghty raised concerns the assessment could lead to the agency vetoing mining activity. In a March 9 letter to McLerran, he said that if EPA were to invoke a section of the Clean Water Act that allows it to restrict or bar use of certain waters for dredge or fill materials, it could have the potential to "extinguish" the state's mineral rights and leases held by others.
McLerran said Friday that EPA isn't at a point where a decision on whether to take that step might be made.
Ruth Hamilton Heese, a senior assistant attorney general in Alaska, said in an email that the state, in reviewing the assessment, will, among other things, be looking closely at the data, methodologies and assumptions used, whether the assessment is based on appropriate modeling for the region, and whether it contains any unfounded bias involving any particular development.
"Although we are greatly concerned that there is no legal authority for this assessment, we will thoroughly evaluate it and seek to protect and promote the best interests of the state, its resources, and its citizens," she said.
Some conservationists and others hailed EPA's action Friday.
Lindsey Bloom, a commercial fisher and organizer with Trout Unlimited, said her first impression of the assessments was that it gives her some peace of mind.
"After all the years I've fished in Bristol Bay and have been watching this issue, it's good to see someone give it the time and depth of knowledge that it looks like EPA has," Bloom said.
Tim Bristol, Alaska program director for Trout Unlimited, said he hopes this is just a first step and will lead to protections for the region against harmful mining activity.
Also on HuffPost:
Marcia G. Yerman: Sen. James Inhofe Seeks to Destroy Landmark EPA Ruling
EPA: Large mine prospect could affect Alaska fish
$107 million to be spent on Pebble permitting
Pebble mine developers earmark $107 million for permitting
EPA: Mining could affect quality of water, fish
State of Alaska raises concerns about EPA study
State of Alaska raises concerns about EPA study
Loading comments… 
AP | By BECKY BOHRER Posted: 05/18/2012 2:12 pm Updated: 05/18/2012 7:13 pm