MINING

Hecla

Save a Generator, Use a Dam

Alaska’s miners are refining energy efficiency

By Rindi White

Mining gets a bad rap as an industry that literally digs in the dirt, yet miners strive to clean up their act with innovative tools and techniques. Efficiency is at the front of mining companies’ business plans, not just for the bottom line but for the sake of good stewardship.

“At Kinross, we strive to incorporate energy efficiency strategies into all aspects of our operations and projects, including mine planning, transportation, metallurgy, electricity consumption, fuel management, and power generation,” says Anna Atchison, director of external affairs in Alaska for Kinross Gold Corporation, the Ontariobased operator of the Fort Knox mine north of Fairbanks.

Last February, Kinross leaders outlined a Climate Change Strategy, budgeting $50 million in 2022 toward environmental, social, and corporate governance-related capital expenditures. One example was an agreement to purchase 100 percent renewable power at its LaCoipa project in Chile. To achieve that, Kinross is using electric shovels, solar power at the mine camp, and an ore conveyor to reduce the need for haul trucks.

In Alaska, the strategy translates to biweekly internal meetings discussing fuel savings opportunities at Fort Knox and monthly internal meetings to identify power opportunities, as well as regular collaboration with Golden Valley Electric Association. Kinross also invested in upgrades to its belt system to run faster and therefore save power. An autogenous grinding method reduces the energy intensity of the mine’s milling circuit.

The mill at Fort Knox will also process gold from the Manh Choh project being developed near Tok, with ore hauled by a fleet of trucks. Kinross is purchasing fifty new trucks that exceed the latest US Environmental Protection Agency emissions standards, resulting in a 90 percent reduction of PM2.5 (particulates less than 2.5 micrometers in diameter that cause haze and can penetrate deeply into lung tissue). Although particulate pollution has no direct impact on climate change, air quality has been a concern of residents along the haul route.

Kinross says its strategy is in line with its corporate values and its commitment to sustainable mining.

Community Partnership

In Southeast Alaska, mines near Juneau have access to abundant energy from local hydropower projects, yet minimizing consumption still pays off.

Hecla Greens Creek mine, located on the City and Borough of Juneau’s slice of Admiralty Island, is the largest customer of Alaska Electric Light & Power (AEL&P), which produces nearly 100 percent of its power through five hydroelectric projects in the Juneau area.

Hecla has primarily used hydropower since 2009, except for diesel backup generators. In 2021, 95.3 percent of Greens Creek’s power came from hydropower, the company reports.

For the remainder, the mine has its own power facilities. “We still need to keep our generators on site available to run at all times,” says Mike Satre, director of governmental affairs for Hecla.

Hecla’s reliable need for electricity reduces bills for the average AEL&P

Kinross

customer by as much as 25 percent, says AEL&P Vice President and Director of Consumer Affairs Debbie Driscoll. Included in that cost figure is AEL&P’s other primary interruptible customer, Princess Cruise Lines.

“Juneau was also the first port in the world to connect a cruise ship to shore power in 2001, something that is now done in multiple ports around the world,” AEL&P staff stated in a 2021 presentation to the City and Borough of Juneau.

Interruptible customers have lower priority than AEL&P’s residential and business accounts. Only after the demands of those customers have been met can Greens Creek and Princess receive power. In effect, AEL&P sells surplus power to Greens Creek and Princess.

“As a regulated utility, AEL&P follows a set process for determining how much money should be collected from firm customers through rates. Since AEL&P’s sales of excess hydropower to Greens Creek are fairly consistent, there is an assumption in the rate calculation process that AEL&P will sell a certain amount of electricity to Greens Creek, and that assumed revenue is used to reduce the amount that would otherwise be paid by firm customers through rates,” Driscoll explains.

By and large, the arrangement has been a win for Greens Creek and for AEL&P ratepayers alike, making rates the lowest among large, regulated utilities in Alaska and, at 12.52 cents per kilowatt-hour, slightly lower than the national average of 13.20 cents per kilowatt hour.

Since 2009, Greens Creek estimates it has saved Juneau ratepayers around $70 million, a number AEL&P echoed in its 2021 presentation to the City and Borough of Juneau. Hecla has also offset at least 70 million gallons of diesel that would have otherwise been used for power production.

While Satre says the partnership with AEL&P is the primary way Hecla reduces greenhouse gas emissions, it also minimizes diesel use in its fleets by using the newest, most fuel-efficient equipment available.

The company also goes to significant lengths to treat and reuse water on site when possible. “The main user of fresh water is our mill; however, we have been able to recycle water from the mill and mine and use it in those same processes again,” Satre says. “In 2021 we pumped 306 million gallons of freshwater to use in our operations and recycled 424 million gallons. A total of 1.3 billion gallons of water were treated, and 590 million gallons were discharged.”

More Hydropower on the Way

North of Juneau, Coeur Alaska’s Kensington Mine mainly operates with power from diesel generators. The company in 2019 finished an extensive refit of seven underperforming diesel generators, replacing them with four high-efficiency ones. The move decreased fuel consumption by 25 percent and improved emissions by 85 percent, company officials said at the time. Those numbers still hold; the higher-efficiency generators have allowed the mine to increase production of gold at a relatively flat rate of diesel consumption with 85 percent less particulate matter, 90 percent less carbon monoxide, 90 percent less sulfur dioxide, 96 percent fewer volatile organic chemicals, and 10 percent fewer nitrogen oxides than the pre2019 generators.

To further improve Kensington’s emissions and reduce reliance on diesel fuel, Coeur Alaska hopes to become the largest customer of Juneau Hydropower Inc., a company that is building a dam at Sweetheart Lake. The Sweetheart Lake project is expected to generate 19.8 MW of power, or about 116,000 MWh throughout a year. Kensington will require about 62,000 MWh yearly. If all goes according to plan, the hydropower project could be running by 2025 or 2026.

The project has challenges. Kensington is located forty-five miles north-northwest of Juneau, while Sweetheart Lake is about thirty-three miles south of downtown Juneau. The project would need three underwater cables and an agreement from AEL&P to “wheel” the power through the Snettisham transmission line to Kensington. “Wheeling” is using another owner’s transmission line to carry power from one site to another. Driscoll says AEL&P is evaluating if the transfer can be done without burdening its power customers with extra costs or

reduced reliability.

Duff Mitchell, managing director of Juneau Hydropower Inc., is excited about collaborating with AEL&P and supporting Juneau’s community goals of additional renewable energy and reducing borough-wide emissions. The additional hydropower will benefit the area—and cut Kensington’s reliance on diesel generation drastically.

“Obtaining line power would help us meet our company’s environmental goals of reducing greenhouse gas emissions. Coeur Mining, Coeur Alaska’s parent company, has a target of 35 percent reduction in net intensity by the end of 2024,” says Rochelle Lindley, manager of community and government affairs for Coeur Alaska.

Bonus Bonanza

Along with electricity, Juneau Hydropower Inc. plans to lay fiber-optic cable to allow the company to remotely control the Sweetheart Lake dam. As a bonus, the cable would provide internet connectivity throughout the borough, outside of Juneau’s core area. Mitchell says Juneau Hydropower’s business plan is not to compete with others providing internet service, but it will partner with providers interested in using its infrastructure. Similarly, he says, his plan is not to compete with AEL&P but to assist the community’s growth by providing new resources of energy for electrification of cars or cruise ship docks.

The third facet of the Sweetheart Lake project is to bring heat to downtown Juneau buildings using seawater heat pumps through its subsidiary, Juneau District Heating. Heat pumps will take in seawater, siphon off a few degrees, and push the slightly colder seawater back to Gastineau Channel. The extracted heat raises the temperature of a water reservoir to 180°F, which is shared with multiple buildings in downtown Juneau. Any building currently using a diesel-fired boiler will be able to convert to lower-cost, zero-emission central seawater heat.

Two seawater heat pump projects are already in place in Alaska: at the Alaska SeaLife Center in Seward and the Ted Stevens Marine Research Institute in Juneau. Mitchell points to a similar seawater heat system being designed for Helsinki. The capital city of Finland announced the $400 million plan in October, just as the country is facing a winter without natural gas imports from neighboring Russia.

Juneau Hydropower’s three-pronged plan—electricity, heat, and data—has a price tag of approximately $200 million, mostly funded privately and with a lowcost loan from the US Department of Energy, Mitchell says. The private funders include Juneau investors and an agreement with J-POWER USA, Japan’s largest hydropower operator. J-POWER is uniquely positioned to take part in the project; the company has developed sixty-one hydropower projects throughout Japan with more than 1,500 miles of high-voltage transmission line, including submarine cables like those Juneau Hydropower will use.

A key part of Juneau Hydropower’s business model is having an anchor customer for Sweetheart Lake at Kensington Mine. Coeur Alaska’s strategy to cut energy expenses and expand or extend the life of the mine enables more investment back into the community and provides a more secure and stable tax base, Mitchell says.

As the largest customer of Alaska Electric Light & Power, Hecla Greens Creek Mine lowers electric bills for Juneau residents while tapping hydropower for its operations. Above are the mine's Hawk Inlet facilities.

Hecla

Gallon by Gallon

Coeur Alaska finds energy efficiency in other ways, too. Lindley points to incremental innovations, such as ensuring lube oil is up to temperature whenever a generator must start due to power load requirements. That simple step allows the company to reduce engine idle time, and Lindley says it adds up to significant savings quickly.

“The request to start another engine occurs between one to four times per shift, and as a minimum [preheating lube oil] reduces the amount of diesel combustion by 330 gallons a day,” she says.

Similarly, shifting ventilation throughout the mine to an on-demand method has brought significant savings. “Ventilation on demand allows fans in areas of the mine that do not have active personnel in the area to be shut down, reducing the power consumed by ventilation by about 4,800 MWh per year,” Lindley says.

In another small but significant effort, Coeur Alaska is testing the use of a fuel catalyst, an additive that reduces smoke, reduces detonation, and improves fuel economy in diesel engines. Lindley says a trial run of a fuel catalyst began at Kensington in November. At other sites, the catalyst has shown fuel savings of 4 to 8 percent. If the catalyst trial proves out, she says, there would be an estimated saving of 480,000 gallons a year in Kensington’s power plant.

Measure by measure, step by step, the end goal is increased efficiency, which both reduces the overall costs of mining and helps mine operators meet company-wide environmental goals. It all adds up.