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EPA blocks Pebble copper mine in Alaska to protect Bristol Bay salmon ecosystem

The US Environmental Protection Agency (EPA) issued a Final Determination under Section 404(c) of the Clean Water Act (CWA) that blocks the development of Northern Dynasty Mineral’s proposed Pebble copper and gold mining project in Alaska. The ruling prohibits certain waters in the South Fork Koktuli River and North Fork Koktuli River watersheds from being used as disposal sites for the discharge of dredged or fill material for the construction and routine operation of Pebble Limited Partnership’s (PLP) mine as described in its permit application.

The ruling also prohibits future proposals to construct and operate a mine to develop the Pebble deposit that would result in the same or greater levels of loss or change to aquatic resources.

The Final Determination also restricts the use of the South Fork Koktuli River, North Fork Koktuli River, and Upper Talarik Creek watersheds as disposal sites for the discharge of dredged or fill material associated with future proposals to develop the Pebble deposit that would result in adverse effects similar or greater in nature and magnitude to those associated with the Pebble 2020 Mine Plan.

The prohibition and restriction in EPA’s Final Determination only apply to certain discharges of dredged or fill material associated with developing the Pebble Deposit. This action does not apply to any current or future resource development projects in the state of Alaska.

The action marks the third time in 30 years, and the 14th time in the 50-year history of the Clean Water Act, that EPA has used its Section 404(c) authority.

The EPA says that by barring the development of the Pebble mine project, it is helping to protect Bristol Bay, the most productive wild salmon ecosystem in the world.



Pebble. The Pebble deposit contains copper-, gold-, and molybdenum-bearing minerals and is located at the headwaters of the Bristol Bay watershed in Southwest Alaska. The Pebble deposit underlies portions of the South Fork Koktuli River, North Fork Koktuli River, and Upper Talarik Creek watersheds, which drain to two of the largest rivers in the Bristol Bay watershed, the Nushagak and Kvichak Rivers.

Since 2001, Northern Dynasty Minerals Ltd. (NDM) and subsequently the Pebble Limited Partnership (PLP) have been conducting data collection and analysis as part of efforts to pursue the development of a large-scale mine at the Pebble deposit. NDM says that the Pebble deposit is the world’s largest undeveloped copper and gold resource.

PLP was created in 2007 by co-owners NDM and Anglo American PLC to design, permit, construct, and operate a long-life mine at the Pebble deposit. In 2013, NDM acquired Anglo American’s interest in PLP, and NDM now holds a 100% interest in PLP.

The current resource estimate for the deposit includes 6.5 billion tonnes in the measured and indicated categories containing:

  • 57 billion pounds copper
  • 71 million ounces gold
  • 3.4 billion pounds of molybdenum
  • 345 million ounces silver
  • 2.6 milllion kg rhenium (Since the late 1980s, rhenium has been critical for superalloys used in turbine blades and in catalysts used to produce lead-free gasoline.)

The estimate also include 4.5 billion tonnes in the inferred category:

  • 25 billion pounds copper
  • 36 million oz gold
  • 2.2 billion lb molybdenum
  • 170 million oz silver
  • 1.6 million kg rhenium

Palladium also occurs in the deposit.

Since 2001, NDM and subsequently the PLP have been conducting data collection and analysis as part of efforts to pursue the development of a large-scale mine at the Pebble deposit. In 2020, NDM CEO Ron Thiessen wrote that “after acquiring the property in 2001, the company [NDM] spent more than a decade and close to $1 billion proving it up as one of the greatest mineral resources ever discovered – certainly on American soil.”

According to Thiessen, contained copper at Pebble is equivalent to ~1.3% of all the copper metal ever discovered or produced in the past 10,000 years; contained gold at Pebble is equivalent to ~1.8% of all the gold ever produced; and Pebble is the largest deposit of rhenium in the world.

In the 2020 Mine Plan, PLP proposes to develop the Pebble deposit as a surface mine at which 1.3 billion tons of ore would be mined over 20 years. The project consists of four primary elements:

  1. The mine site situated in the SFK, NFK, and UTC watersheds. This would comprise the open pit, bulk tailings storage facility (TSF), pyritic TSF, a 270-megawatt power plant, water management ponds (WMPs), water treatment plants (WTPs), milling and processing facilities, and supporting infrastructure.

  2. The Diamond Point port;

  3. the transportation corridor, including concentrate and water return pipelines; and

  4. the natural gas pipeline and fiber optic cable.

Under the 2020 Mine Plan, PLP would progress through four distinct mine phases: construction, operations (production), closure, and post-closure. The construction period would last approximately four years, followed by 20 years of operation. Closure, including physical reclamation of the mine site, is projected to take approximately 20 years. Post-closure activities, including long-term water management and monitoring, would last for centuries.

PLP CEO John Shively issued a statement following the EPA’s announcement:

Today’s action by the EPA to preemptively veto the proposed Pebble Project is unlawful and unprecedented. For well over a decade, we have argued that fair treatment under the rules and regulations of the US should be followed for Pebble or any other development project. Unfortunately, the Biden EPA continues to ignore fair and due process in favor of politics. This preemptive action against Pebble is not supported legally, technically, or environmentally. As such, the next step will likely be to take legal action to fight this injustice.

… The EPA decision to try to destroy the Pebble opportunity is just one more piece of the Biden administration’s war on domestic natural resource development. It has attempted to stop mining, fossil fuels development and timber harvesting on many fronts in Alaska. The Biden strategy when it comes to securing the minerals required for its green energy goals seems to be to give some passing support for the development of boutique minerals such as lithium and rare earths in the U.S., but to seek the enormous supply of base metals such as copper needed for EV’s, solar panels, wind turbines, hydroelectric plants, and the associated infrastructure from other nations.

We have seen what happens when our nation is dependent on others for our resources, for instance the Saudis for more oil production. When we go to China seeking the copper and other minerals we need for our green energy transition, the reaction will likely be more problematic and the cost more expensive.

—John Shively, CEO of PLP

Bristol Bay. The Bristol Bay watershed’s fishery resources are a thriving economic driver for the region, generating significant nutritional, cultural, economic, and recreational value. The total economic value, including subsistence uses of the Bristol Bay watershed’s salmon resources, was estimated at more than $2.2 billion in 2019 and results in 15,000 jobs annually. The Bristol Bay Watershed is home to 25 Alaska Native villages and communities and supports one of the last intact, sustainable salmon-based cultures in the world. Salmon provides more than half of the subsistence harvest for some Alaska Native communities in the Bristol Bay region.

The streams, wetlands, and other aquatic habitats in the South Fork Koktuli River, North Fork Koktuli River, and Upper Talarik Creek watersheds provide important spawning and rearing habitat for Coho, Chinook, and Sockeye salmon and provide high-quality habitat for other fishes, such as Rainbow Trout, Dolly Varden, Arctic Grayling, and Northern Pike. The aquatic habitats of the South Fork Koktuli River, North Fork Koktuli River, and Upper Talarik Creek watersheds also provide critical support for downstream habitats.

By contributing water, organic matter, and macroinvertebrates to downstream systems, these headwater areas help maintain downstream habitats and fuel their fish productivity. Together, these functions—direct provision of high-quality habitat and indirect provision of other resources to downstream habitats— support the valuable fisheries of the Bristol Bay watershed.

EPA’s assessment was that unacceptable adverse effects on the anadromous fishery areas in the Bristol Bay watershed would be likely to result from discharges of dredged or fill material associated with mining from the Pebble deposit. (Anadromous fishes hatch in freshwater habitats, migrate to sea for a period of relatively rapid growth, and then return to freshwater habitats to spawn.)


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