Mining

Bagasse to the Rescue!

By Kristine Edwards

When I first visited the Crystal Mine site (part of the Basin Mining Area Superfund Site in Jefferson County, Montana) back in 2006, I was so shocked by how bad it looked that I vowed to myself to get it cleaned up before I retired.

Acid mine drainage from old mines is a big problem in historic mining districts across the U.S. The pH of mine water at the Crystal Mine is around 2.7, which is pretty acidic (on a scale of 1-14, with 7 being neutral pH and what we like to see in uncontaminated water), and carries significant concentrations of heavy metals. In order to treat the drainage, we’re working with our contractor on a treatment system.

An environmental contractor was working on mine sites in Peru when they came across a locally grown material that showed a lot of promise for treating acid mine drainage. It’s called sugar cane bagasse, a byproduct of sugar cane. The bagasse is a light weight fibrous material. Additional research at the University of Colorado (Boulder) using sugar cane bagasse showed promise even at low pH levels and low temperatures. Since the Crystal Mine site is at 8,000 ft elevation, it can get very cold there in the winter.

 

Sugar cane bagasse sample

Sugar cane bagasse sample

 

The bagasse is permeable and promotes biological activity by sulfate-reducing bacteria. This converts sulfate in the drainage to sulfide. Dissolved heavy metals like cadmium, copper, iron, lead, nickel, zinc combine with these sulfides to adhere to the fibers, leaving the water much cleaner.

We’re running a treatability study at the Crystal Mine to see if the sugar cane bagasse works better at treating the drainage from this site than the typical methods. The manure and hay, a step in the process, are coming from a nearby barn and the aged wood chips and saw dust are from a local post and pole operation. So, even though the sugar cane bagasse is coming from Louisiana, we’ll be using some local materials as well.

This will be a test that, if successful, could simplify treatment of acid mine drainage at other remote mine sites in this region. It would also lower maintenance costs, if it works the way we hope it will. The study will run from mid-June to October, and then it will take us about a month to interpret the results.

I hope to have a make a decision on how to clean up the site and the design plan in place by June 2015. The Superfund cleanup process can be long and it’s taken several years to complete the investigation of the site. This treatability study with the sugar cane bagasse will help us design the final treatment system and could be something EPA or the state could use at other mine sites with acid mine drainage. I could then retire with a feeling of having accomplished my goal of cleaning up this site, and perhaps help clean up other sites as well!

 

Kristine Edwards at the Crystal Mine Adit Portal

Kristine Edwards at the Crystal Mine Adit Portal

About the author: Kristine Edwards, a “native” Montanan, has always loved hiking, fishing, horseback riding and backpacking in the mountains of Montana. She was hired by EPA out in Seattle (EPA Region 10), and was fortunate to eventually make it back to Montana after 4 years in Seattle and 3 years in Denver.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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It All Starts with Science: Answering Questions about Mining in Bristol Bay, Alaska

Considering the scope of resources in Bristol Bay – a 37.5 million average annual run of sockeye salmon; $480 million in ecosystem-generated economic activity in 2009; 14,000 full- and part-time jobs from that activity; and 11 billion tons in potential copper and gold deposit – it is no wonder there was significant interest in an EPA science assessment to understand how wild salmon and water resources in the Bristol Bay watershed might be impacted by large-scale mining operations. The public comment periods generated 230,000 responses on the first draft of the assessment, and 890,000 on the second.

This week, after reviewing all those comments and formal peer review by 12 scientists with expertise in mine engineering, fisheries biology, aquatic biology, aquatic toxicology, hydrology, wildlife ecology, and Alaska Native cultures, EPA released its final report, “An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska.”

More than three years ago, several Bristol Bay Alaska Native tribes requested EPA take action under the Clean Water Act to protect the Bay and its fisheries from proposed large-scale mining. Other tribes and stakeholders who support development in the Bristol Bay Watershed requested EPA take no action until a permitting process begins.

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Editor's Note: The views expressed here are intended to explain EPA policy. They do not change anyone's rights or obligations.

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Building Appreciation for the Environment with the Next Generation

Every year, the Mid-Atlantic Water Protection Division does a few Earth Day presentations at local schools. We have always felt that it’s important to educate young people about protecting the environment.

In certain ways, educating the next generation is one of the most important parts of EPA’s entire mission. This year, we went to a few schools including Julia R. Masterman at 17th & Spring Garden Streets in Philadelphia. Masterman is a public magnet school that includes both a middle school and a high school with young enthusiastic teachers, who continually use their science curriculum to talk about environmental issues.

Sometimes a short presentation on the class’s Smartboard about the history of EPA is offered, including old photos of the Cuyahoga River fire which happened way back in 1969. Or we talk about the first Earth Day in 1970, and how it led to the formation of the EPA. Other times, we change speeds a bit and do a simple chemistry experiment using red cabbage juice as a pH indicator. pH is a measure of acidity or alkalinity and changes in pH can also affect the aquatic life in a stream.

For an experiment about pH, we use red cabbage juice because it changes colors quite dramatically when mixed with baking soda, vinegar or even tap water. Purple, dark green and light blue…even a bright yellow can easily be created with the right substance. Middle schoolers love looking at the different colors, and some are inspired them to ask us a few questions about the Schuylkill River or other water bodies in the Mid-Atlantic Region. Read about successful restoration of pH-impaired streams in the Mid-Atlantic states of Pennsylvania and West Virginia.

What are some of the lessons you’ve shared with young people about protecting the health of our streams and rivers? The future of our environment is in their hands.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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