Spring 2015 Project Update
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Spring 2015
2015: The Year It All Comes Together


For the past three years, we’ve been working on a lot of moving parts to complete the remediation of past environmental problems at the old Holden Mine site. This is the year we bring all those parts together.

We made a lot of progress on the Holden Mine Cleanup Project last season.  When the mine was constructed more than seven decades ago, the tailings were piled at a very steep angle to Railroad Creek. We have reshaped and recovered much of the eight million tons of tailings that sit in three piles on 90 acres of the site. We started reshaping one of the waste rock piles with soil to restore vegetation last season. We plan to finish reshaping, regrading and revegetating the tailings and the waste rock piles in 2015.

Tailings Pile 1 Before
Tailings Pile 1 After
We also completed constructing a fresh water diversion for surface water around the site in 2014.  This will reduce the potential for erosion of the tailings pile.  
Copper Creek in temporary channel during streambed reconstruction
We’ve nearly finished our most demanding project: installing the below-ground barrier wall to collect contaminated water. Digging down as deep as 90 feet to construct a wall made of clay and cement is challenging.  With about 80% of the barrier wall complete, it will take us another month to finish the work. This year, we will also complete the groundwater collection system. 
Barrier Wall Construction

The Water Treatment Plant

Our big project this year is building a plant to treat the contaminated water we’re collecting from the tailings and waste rock piles.   The treatment plant will neutralize and filter the contaminated water using lime and other chemicals.  This process will ensure that the treated water discharged into Railroad Creek complies with government clean water standards.  The byproduct from the water treatment plant is an inert sludge that will be safely stored in an engineered repository on top of the re-graded tailings.
Future Water Treatment Plant

What's Ahead in 2016

We expect to have 250 to 300 employees on site through next year.  Our 2016 plans include:
  • Revegetating the cover soil on the tailings and waste rock piles
  • Reclaiming the quarry, borrow areas and Lucerne boat ramp area
  • Replacing Holden Village buildings
  • Wetlands mitigation
  • Barging equipment and other supplies to Lucerne through next year and beyond, on a reduced schedule.
  • Operating the water treatment plant 
Holden Village will resume its normal visitor season next year.  We are working with the Village to discuss the best way to move forward with the project and have the least impact on their programs if we need to use their facilities in 2016. 

Community Meeting - April 29, 2015

Join us on April 29 for our annual community meeting and project update. Rio Tinto Project Owner Dave Cline will make a presentation and answer audience questions about the project. 

When: Wednesday April 
29, 2015 from 4 - 6:30 pm
Where: Campbell’s Resort, Centennial Ballroom, 104 W. Woodin Avenue, Chelan, Washington


Rio Tinto has joined Magnus Pacific in donating $10,000 each to the Lake Chelan Community Hospital Foundation’s health program. The contribution will be used to expand the Foundation’s Club Max Programs, which educate and motivate children to make healthy decisions, specifically focusing on exercise and nutrition.
Rio Tinto’s Dave Cline (second from left) and Magnus Pacific’s Robert Kirby (second from right) join members of the Lake Chelan Community Hospital team in Holden Village.

For More Information 

Check out our project video at to learn more about the past, present and future of the Holden Mine Cleanup Project. Click on our “Links” tab for more information about Rio Tinto and our expertise in and commitment to managing legacy sites.

About Rio Tinto

Rio Tinto's business is finding, mining and processing mineral resources. Major products are aluminum, copper, diamonds, thermal and metallurgical coal, uranium, gold, industrial minerals (borax, titanium dioxide and salt) and iron ore. Activities span the world and are strongly represented in Australia and North America with significant businesses in Asia, Europe, Africa and South America.

The Holden Mine Project is part of Rio Tinto’s Legacy Management group. The Legacy Management group works to ensure that old historic sites inherited through the acquisition of other entities are made safe, that all problem areas are addressed cost-effectively, and that there is a sustainable socioeconomic future for the community and a minimal burden of aftercare for the historic sites. For more information visit

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