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Proposed Pebble Mine Has Alaskan Community Focused on Critical Science and Policy Issues

DILLINGHAM, Alaska—In the remote and undeveloped hills northeast of here, the clear waters of great sub-Arctic rivers and their tributaries carve an intricate web across the tundra. Upper Talarik Creek flows into Lake Iliamna, one of the largest lakes in North America and home to millions of sockeye salmon, and Lake Iliamna empties into the Kvichak River. The Koktuli and Stuyahok flow into the Mulchatna River, which flows into the broad Nushagak. In time, all of these waters flow into Bristol Bay, perhaps the most productive wild salmon fishery remaining in the world.

The land between Lake Iliamna and the Mulchatna holds other riches, as well. Over the past 30 years, an almost mythic lode of valuable minerals has been discovered there, billions of tons of ore containing copper and gold, molybdenum, silver and other deposits that could be worth a half-trillion dollars.

In the towns and villages near the mine site, and in corporate boardrooms thousands of miles away, the discovery has given rise to a question: Can one of the largest mines in the world be built in an earthquake zone above Bristol Bay without disrupting an environment that supports abundant wildlife and rich human cultures?

The proposed Pebble Mine has inspired an intense political and social conflict, but as residents of this remote city and of villages throughout the Bristol Bay watershed try to chart the future, many of their questions are about science and engineering. When the AAAS Arctic Division met here recently, those questions were explored in detail during a public forum and technical sessions.


The tundra landscape north of Bristol Bay where the Pebble Mine would be built. | Photo © Tim Troll

“The Pebble Mine is a hugely important issue for people in Dillingham and southwestern Alaska,” said Lawrence K. Duffy, executive director of the AAAS Arctic Division. “It literally will determine their future. People from many different walks of life came together at the meeting, and we saw them working together to explore and evaluate the science. It’s unusual to see a scientific meeting become a forum for public engagement on a regional scale, but it certainly was inspiring.”


The annual Arctic Division meeting—the first ever convened in the Alaskan Bush—spanned four days from 21-24 September at the University of Alaska-Fairbanks Bristol Bay Campus. Though Dillingham is a small, remote city with no road connection to urban centers like Anchorage or Fairbanks, more than 75 scientists, policymakers, mining officials, and environmental leaders flew in from Alaska, Canada, and the Lower 48, plus one delegation from the Kamchatka Peninsula in Siberia. They were joined at a half-day Pebble Mine forum by more than 150 residents of the region, including students, teachers, Alaska Native leaders, fishermen, and business executives. The meeting was organized by Duffy; division President Todd Radenbaugh, director of the Environmental Science Lab at the Bristol Bay Campus; and Al Teich, senior science policy adviser at AAAS and liaison to the division.

While many people in the Lower 48 have yet to hear of the Pebble Mine controversy, in Alaska the conflict is well-known—and escalating. It has provoked lawsuits and high-priced public relations campaigns; it has been on the statewide ballot and was the focus of a special election on 4 October in the borough near the proposed mine site.

There were flashes of that passion when the Arctic Division forum convened in the gymnasium at Dillingham Middle School, but more striking were the sober tone of the discussion and the focused questions from the audience. As they consider the benefits and risks that the mine may bring to the area, many people want to know whether mining waste could escape the Pebble site to damage waterways or hurt fish, and whether mine engineering can build dams and containments strong enough to endure for hundreds of years in an active earthquake zone.

To former Alaska Senate President Rick Halford, a bush pilot who served more than 20 years as a Republican in the Alaska Legislature, the mine poses unacceptable risks. “The location is incredible,” said Halford, a forum panelist. “It is a very, very critical location. If God were challenging us, he couldn’t have found a place to put that mine that has more challenges.”

But John Shively, the chief executive officer of Pebble Limited Partnership, told the AAAS forum that the partnership is committed to assessing the risks and challenges before deciding whether to proceed. For that reason, he said, the partnership formed by international mining companies has thus far invested $120 million to have some 500 researchers conduct what amounts to “the largest science project ever undertaken for any mining project anywhere in the world.

“If you look at the sensitivity of the project,” Shively said, “if you look at where we are, it was absolutely required that we do this.”

Mining on a Monumental Scale

The site proposed for Pebble Mine is state-owned land just north of Lake Iliamna, about 200 miles southwest of Anchorage; small villages are scattered through the region, but their footprint is light. Seen from above, the land is a different hue from the surrounding tundra—and that’s what tipped off mining interests that the site had potential. Mineral exploration began in the mid-1980s, but fell dormant in much of the 1990s.

Over the past 10 years, the mining claims have been obtained by the Pebble partners—Northern Dynasty Minerals Limited of Canada and Anglo American PLC, based in London. Exploration resumed, and with every passing year, the estimates of the mine’s potential wealth have grown.

It is impossible to understand the Pebble debate—and the scientific and policy challenges presented by the proposed mine—without appreciating the sheer enormity of the project. While Pebble has not submitted a formal plan to Alaska mining regulators, the development would require a huge investment. Company documents and past statements by officials indicate that Pebble would be one of the biggest mines in the world, and possibly one of the richest. It would be the biggest mine in Alaska by far, some 30 times bigger than the next biggest mine, so big that every other mine in the state, combined, could fit inside of it several times over.

The ore deposits. According to Pebble’s analysis, there are 10.75 billion tons of ore at the site, which contain mineral deposits of phenomenal value: an estimated 80.6 billion pounds of copper; 5.6 billion pounds of molybdenum; and 107.4 million ounces of gold, plus smaller amounts of silver, rhenium and palladium. Estimates of the deposits’ value range from $300 billion to $500 billion. But it is a low-grade sulfide deposit: After the minerals are extracted, about 99% of the gross volume will be left over as pulverized rock, with a sulfide-sulfur content in some of the tailings that will require careful management.

The infrastructure. Past reports have indicated the project would require a 104-mile primary road to connect a deep-water port at Cook Inlet with the mining site. Shively puts the distance at 86 miles. The road would have to cross as many as 120 rivers and small streams. Pipelines would carry fuel and slurry to and from the site. State Representative Bryce Edgmon (D-Dillingham) told the forum that Pebble would build a gas-fired 378 megawatt turbine to generate electricity, a power plant big enough to serve the entire Anchorage area. And Pebble has applied for the rights to up to 35 billion gallons of water per year, much of it from local rivers and groundwater; that’s nearly four times the amount of water used annually by customers of Anchorage Water and Wastewater. The partnership would build an advanced water treatment plant to meet state standards for water discharged back into the environment; the water would have be close in temperature and chemical content to natural waters in the area.

The mine. The Pebble claim covers 153 square miles; at least 15 square miles would be needed for the mine and ponds to contain the leftover tailings, reports Pebble Science, a collaboration of Alaskan researchers working for universities, tribes, and non-profit groups. According to early conceptual designs, the western portion of the deposit would be accessed through open-pit mining, and the eastern portion likely would be mined underground. The open pit would cover more than two square miles and would be 1700 feet deep—deep enough to fit the Empire State Building, with room to spare.

The mining wastes. Two areas would be set aside for storage of waste rock, or tailings, behind dams. One would cover an estimated 20 square miles, submerging some areas beneath hundreds of feet of tailings and water. To hold that waste in place, Pebble would build an earthen dam 740 feet high—higher than the Hoover Dam, and nearly as high as the Oroville Dam in California, the nation’s tallest dam.

Monumental Social and Political Conflict, Too


The Pebble Mine forum convened 22 September in the gymnasium at the Dillingham Middle/High School. | Photo copyright Todd Radenbaugh

Mining on this scale, in such a sensitive area, has generated an epic clash that is playing out in Alaska politics, economic sectors, and local communities, and drawing in partisans all over the world.


Predictably, the conflict pits conservationists against those who favor development. Some say it boils down to a clash between mining and fishing, two of Alaska’s primary traditional industries. But the fault lines are deeper and more complex than that. For example, many Alaska Natives oppose the proposal, but others, especially in some villages near the mine site, are among the most outspoken supporters. Some elected officials and Alaska Native leaders who typically favor mining and other development oppose Pebble. Others favor economic growth, but want to preserve the living-off-the-land culture that is traditional in the Alaskan Bush. Those who favor the state’s primacy in regulating mines oppose those who favor federal involvement, including the recent decision by the U.S. Environmental Protection Agency to conduct a scientific assessment of the Bristol Bay watershed.

In an area where population is slowly declining and high-paying jobs are scarce, Pebble officials have projected that the mine would create about 2000 jobs during construction and about 1000 high-skill, high-wage operating jobs over the course of 25-35 years. (The mine could last 100 years or more.) In addition, they predict spending on the project would create an economic boom throughout the region and generate a windfall in state and local tax revenue. And, they say, it would produce minerals crucial for 21st century technology—copper, for example, that is used in computers and wind turbines.

Video of the public forum on the proposed Pebble Mine held at the AAAS Arctic Division annual meeting

Video of the public forum on the proposed Pebble Mine held at the AAAS Arctic Division annual meeting

But opponents say the mine would jeopardize a fishery that hosts the world’s largest remaining run of wild sockeye salmon, plus the world’s four other types of salmon and many other fish. The fishery creates thousands of full- and part-time jobs and generates an estimated $400 million to $500 million a year, sustainably.

The perceived threat to the fishery has galvanized an alliance between sport and commercial fishing interests, conservation groups, and some Alaska Native organizations. Prominent Republican lawmakers normally allied with the mining industry have opposed Pebble—including influential U.S. Senator Ted Stevens, before he died in 2010, and Halford, the former president of the Alaska Senate.

Among Alaska Natives, “the opposition to Pebble is overwhelming at this point,” Tiel Smith, land and resource manager for the Bristol Bay Native Corporation (BBNC), told the AAAS forum. Of 9000 BBNC shareholders, he said, 70% “oppose the Pebble prospect and view it as a larger risk than they want to consider.”

Pete Andrew, a BBNC board member, is a subsistence and commercial fisherman. He lives with his family in Dillingham, but he grew up in the 1960s in a traditional Yup’ik village at New Stuyahok, 50 miles north on the Nushagak. His father was a commercial fisherman, and the family hunted, fished, and harvested berries and other plants, living in close harmony with the cycle of the seasons as their ancestors had done for countless generations. Even today, most residents there follow that traditional lifestyle.

“Everything that is my being is because of salmon,” Andrew said in an interview at the AAAS Arctic Division meeting.

“Our life revolves around it,” added his daughter, Kristina.

For that reason, the mine proposal “scares the hell out me,” Andrew said. “The native people of this region have survived through millennia by sheer skill and effort to make a living in this harsh environment. And now we’re facing something that totally—it may not happen immediately, it may take years—but in the millennia to come, it may totally decimate a lifestyle, a livelihood, that would not be the same.”

Searching for Answers in Science

Sarah O’Neal, a fisheries biologist, has been doing research at the Pebble site for four years under Carol Ann Woody, whose experience includes 13 years as a fisheries research scientist with the U.S. Geological Survey. When O’Neal described the landscape during a technical session at the meeting, she talked about the water—slogging across the tundra and sinking up to her thighs in water as she moved from one stream to the next.


Fisheries biologist Sarah O’Neal (right) and Daniel Chythlook of the Bristol Bay Native Association identify previously unsurveyed streams in and around the proposed Pebble Mine. O’Neal is associate director of Fisheries Research & Consulting. | Photo courtesy of Carol Ann Woody

Shively, speaking at the forum, made clear that Pebble is aware that water poses complex challenges at the site. Perhaps before the end of the year, he said, Pebble will release a massive “environmental baseline document” of 53 chapters and 20,000 pages. Water—water as snow, the chemical character of the water, how it moves above ground and below, the life it supports—will be a key focus of that document.


While he did not discuss details of the report, earlier information released by Pebble and other research indicates that engineers will have to address both how water is handled on the site and how to prevent it from flowing off the site.

Some researches say construction of such a large mine will disrupt or destroy dozens of miles of streams and tributaries; Shively disputed that. Initially, researchers say, there was an assumption that many of the rivers had no fish. But that proved incorrect. “We found fish virtually everywhere we looked,” said O’Neal, associate director of Anchorage-based Fisheries Research & Consulting.

Another threat to fish is less direct. If water leaches from the mine site, researchers said at the technical session, that could have an impact throughout the watershed.

Kendra Zamzow, an environmental chemist and the Alaska representative for the Center for Science in Public Participation, has been studying water in the area since 2009. It is, she said, “insanely pure.” But Zamzow and other researchers said a potential threat arises from 10 billion tons of sulfide ore stored in tailing ponds.

A key focus is the soil beneath the tailings. There are bedrock shelves, O’Neal explained, “but they would be dwarfed by the size of the tailings.” Most of the soil beneath the tailings would be silty sand and gravel—which is, she said, “highly porous.”

It’s likely, researchers said, that water leaching through sulfide mine wastes could create an acid solution. That, in turn, could dissolve copper and other trace metals left in the pulverized wastes. If copper seeps down through the soil beneath the tailings, O’Neal said, that creates a “high potential” for contamination in the pristine watershed beyond the mine.

According to Zamzow’s research, the water in nearby rivers and streams is naturally low in alkalinity, which means it has less power to buffer the acid. And while organic material in the water system would be expected to absorb the copper, there is not much organic material in the water. Her conclusion: If copper-contaminated water seeps beneath the tailing area and migrates to nearby waterways, “there will be a point, probably fairly soon… when it becomes available for aquatic life.”

That could present an acute danger. “Copper is highly toxic to fish,” O’Neal told the AAAS audience. “Two to 10 parts per billion of copper can impair a salmon’s ability to smell—its ability to recognize mates, to recognize prey or predators.” Such contamination also could compromise a fish’s brain function and disrupt its sense of direction, which could reduce its ability to navigate upstream to spawn.

A Challenge Measured in Centuries

For mining engineers, then, a key question is whether that leaching of acid and copper from the mine site can be prevented.

“We have to keep things that do not belong in the ecosystem behind the tailing facility,” Shively said at the forum. However, he cautioned against exaggerating threat. If the mine were fully developed, “there could be 10 billion tons of leftover material,” he said. “It is primarily dirt… People have been led to believe that all 10 billions tons is poison. [But] you could take the tailings and mix it in a glass of water… and drink that, and it would do no harm.”

When a member of the audience asked how specifically Pebble would manage the interaction of groundwater and surface water, Shively offered no specifics. “It’s an excellent question,” he said. “We certainly recognize, and our studies have shown, that transfer does take place…. How we’ll manage that will be part of our ultimate plan.”

In Shively’s view, new technology and modern engineering employed at mines developed recently in Alaska suggest it is possible for a large mine to exist in harmony with the environment. Critics counter by naming other copper mines that have contaminated groundwater even though they’re located in arid locations.

And some suggest the challenge posed by Pebble must be seen in terms not of decades, but of centuries. Even nuclear waste has a half-life, Halford said, but the sulfide tailings do not. Far in the future, the tailings may be re-distributed by earthquakes or by floods or droughts associated with climate change. While the mine might be played out in 100 years, the risks would endure in perpetuity.

“Our salmon resources are very important,” said Tim Troll, southwest Alaska program director for The Nature Conservancy. “It’s one thing to put them at risk for the next 50 or 100 years. It’s another thing to put them at risk until the next glacial age.”

The Importance—and Limits—of Science

As the forum neared its end, questions from the audience seemed to seek assurance that science would determine whether to proceed with the mine. But while science can inform the debate, other critical factors also will shape the decision, said forum co-organizer and moderator Al Teich, a senior science policy adviser at AAAS.

“It’s a political decision, it’s a value decision, it’s balancing different weights of different interests [and] the different needs of the people of Alaska,” Teich said. Science “can answer the technical questions, but it can’t tell you which factors are more important than others—that’s up to the people to decide, through their elected representatives.”

To be sure, the science is still evolving. Even after Pebble’s massive report is released, the partnership will continue its research before submitting a formal application for a mining permit, and Shively said that step may be 18 months away. The EPA’s comprehensive scientific assessment of the Bristol Bay region could be ready in a year. And other researchers are focused on a range of issues, including how biodiversity supports the fishery’s long-term health and how that might be impaired by the mine.

Clearly, however, business, politics, and law will have powerful influence on the mine’s future.

Northern Dynasty Minerals Limited—one of two Pebble partners—earlier this year put its 50% share of the project up for sale; as of the end of August, news reports said no offers had emerged. Meanwhile, in results released this week, an initiative intended to block the mine development was narrowly approved in a mail-in vote by residents of Alaska’s Lake and Peninsula Borough near the mine site. (The borough does not include Dillingham.) A court challenge is likely.

Tom Crafford, director of the Office of Project Management and Permitting for the Alaska Department of Natural Resources, told the forum audience that the project should be allowed to go through the state and federal permitting process before people come to conclusions about the mine’s viability and environmental impact. Shively agreed.

“I completely understand why people are concerned about Pebble and why, at this point, most people in the region oppose it,” he said. “I think there are opportunities here to make not only a project that we would be proud of, but that ultimately the region can be proud of. That’s something you have to do. If we can’t do that, then it’s going to be very, very difficult [to proceed].”

He added: “We have never even said that we’re going to [seek a] permit. We may not.” It’s possible, he added, that Pebble initially would seek to mine only a part of the prospect.


Kristina Andrew and her father, subsistence and commercial fisherman Peter Andrew Jr. | Photo by Edward W. Lempinen

But mine opponents believe that, with so much potential wealth below the tundra soil, there will always be an interest in excavating it. And if the Pebble project were approved, they say, it could open the way to mining development by other companies that are already staking many other claims on the tundra upstream from Bristol Bay.


Today, opponents are preparing for battle that could last decades, much as conservationists have fought oil and gas drilling in the Arctic National Wildlife Refuge since the 1970s. Pebble would have to win 67 different permits before it could begin extracting minerals—and opponents could contest every one of them.

“Most of these big arguments tend to be arguments between the present and the future,” Halford said at the forum. “It’s a fallacy of democracy—it over-represents the present and under-represents the future. But science can help us to understand what the future might bring.

“The bottom line is that a lot of the people in this room won’t be here, won’t be here on this earth, when the decisions are made. The young people that have been in and out of the room [during the forum] really have an opportunity for leadership on this issue like none other.” Pebble is “critically important to them,” Halford added, “and anything we can do to encourage them to study, to learn, to be involved… will be the best thing we can do on this issue.”

That perspective has resonated with Kristina Andrew, Pete Andrew’s daughter. She had been living in California, but she recently moved home to Dillingham. She’s planning to enroll at the University of Alaska-Fairbanks Bristol Bay campus; she may study business, but as both of her brothers are engineers, she may instead study electrical engineering.

“One reason I moved back was because of this mine—I felt I should fight for my culture,” she explained. “People know that if you want to be involved in this, you have to understand the science. If we depend on clean water, we have to depend on science to teach us how to keep it clean.”


Watch a video of the public forum on the proposed Pebble Mine held at the AAAS Arctic Division annual meeting.

To learn more about the scientific issues related to the proposed Pebble Mine, visit Pebble Science.

View a slide show of the Pebble Mine forum and other events and activities at the AAAS Arctic Division meeting.

Learn more about the Arctic Division and three other AAAS regional divisions.




Edward W. Lempinen

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