Pebble Mine: Devil in the details--and non-details

Pebble Mine is the common name of a mineral exploration project investigating a very large porphyry copper, gold, and molybdenum mineral deposit in the Bristol Bay region of Southwest Alaska, near Lake Iliamna and Lake Clark. The proposal to mine the ore deposit, using large-scale operations and infrastructure, is controversial. Proponents argue that the mine will create jobs, provide tax revenue to the state of Alaska, and reduce American dependence on foreign sources of raw materials. Opponents argue that the mine would adversely affect the entire Bristol Bay watershed; and that the possible consequences to fish populations, when mining effluents escape planned containments, are simply too great to risk. Much of this debate concerns the tentative plan to impound large amounts of water, waste rock, and mine tailings behind several earthen dams at the mine site. ... --wiki

http://en.wikipedia.org/wiki/Pebble_Mine

The Pebble deposit is a massive storehouse of gold, copper and molybdemum, located in the headwaters of the Kvichak and Nushagak Rivers, two of the eight major rivers that feed Bristol Bay. If built, Pebble would be one of the largest mines in the world. Because of its size, geochemistry and location, Pebble runs a high risk of polluting Bristol Bay, one of the world’s few and most productive wild salmon

strongholds that supports a $500 million commercial and sport fishery. For this reason, Trout Unlimited is working with a diverse group of fishermen, guides, lodge owners, Alaska Natives, scientists, chef, restaurant owners, seafood lovers and many others to try to stop the Pebble development and to protect Bristol Bay. 

The proposed mine developers, the Pebble Limited Partnership (PLP) are a consortium of the world’s second largest multinational mining corporation, London-based Anglo American, along with Northern Dynasty, a junior mining company headquartered in Canada. Anglo American’senvironmental track record does not bode well for Bristol Bay and Northern Dynasty has little experience safeguarding the environment having never developed a mine to date. Although PLP has not released its final mine plans, preliminary designs indicate that the Pebble Mine complex would span 20 square miles of state land in the Bristol Bay watershed. Located in a seismically active region, Pebble would require the world’s largest earthen dam to be built, some 700 feet high and several miles in length. Independent scientists have questioned whether the dam could withstand the force of a massive earthquake, such as the 9.2 quake that devastated Anchorage in 1964. 

The dam and 10-square-mile-wide containment pond are intended to hold between 2.5 billion and 10 billion tons of mine waste that Pebble would produce over its lifetime - nearly enough to bury the city fo Seattle, WA. Because the sulfide, or acid-generating, nature of the Pebble ore body, the waste would require environmental treatment in perpetuity. Any release of mine waste into the surface or groundwater has the potential to harm Bristol Bay’s salmon runs. ...

http://www.savebristolbay.org/about-the-bay/about-pebble-mine

Bristol Bay’s Wild Salmon Ecosystems and the Pebble Mine

Key Considerations for a Large-Scale Mine Proposal

Wild Salmon Center and Trout Unlimited have produced a report examining the proposed Pebble Mine and its potential impacts on the wild salmon fishery of Bristol Bay, Alaska. This report describes significant ecological, economic, and cultural concerns raised by proposed development of the Pebble copper, gold, and molybdenum deposit in the headwaters of the Bristol Bay basin, which is home to North America's most abundant wild salmon fishery and the world's largest wild sockeye salmon run. ...

http://www.wildsalmoncenter.org/programs/north_america/pebblemine.php