If you saw this along the Indian Creek Valley Trail during the first couple months of 2020, you may have thought something was awry. You would have been correct. That discharge depositing orange sludge on everything it touches and flowing directly into Indian Creek is water from the old “Big Chief” mine outside of Indian Head; the mine water usually flows into the green catch basin and gets treated by the Max B. Nobel Mine Drainage Remediation Site & Interpretive Wetland Area—also known as the Sagamore treatment system—before it goes into Indian Creek.
Here’s a brief explanation of abandoned mine drainage (AMD) and why it needs to be treated before going into our streams.
Whether near the surface or deep underground, mining exposes buried rock layers containing sulfur rich minerals to the atmosphere. Since they are below a water table or aquifer, the mined area fills with water after it’s closed down. A series of chemical reactions, assisted by underground bacteria and fueled by the surplus of water and atmospheric oxygen, take place producing sulfuric acid and dissolved metals. This acidic, metal-rich water flows out of the abandoned mine and into surrounding streams. If left untreated, chronic pollution from AMD will impair or kill much of the aquatic life within those streams.
You can see the ponds, windmills, and discharge of the Sagamore treatment system pictured above when walking on the trail. AMD from the Big Chief mine is treated here by exposing it to limestone and oxygen. The limestone is slowly dissolved by the acidic water, raising its pH to a level closer to drinking water. Raising the pH allows the dissolved metals (mainly iron and aluminum) to oxidize to solid particles and settle at the bottom of the ponds. After the system has done its work, the treated AMD then flows into Indian Creek.
This is a passive method of AMD treatment therefore the system does not require much technology or oversight, but it does require regular maintenance to keep it working correctly.
Every AMD treatment system in the Indian Creek watershed has differing maintenance requirements, and for Sagamore to work correctly it needs to have the plumbing for the catch basin cleared of mineral deposits approximately every 6 months. If not kept on a consistent schedule, the pipes will be blocked by mineral deposits and the discharge will completely bypass the system at the catch basin—exactly what was happening at the beginning of 2020.
MWA coordinates with Pennsylvania’s Bureau of Abandoned Mine Reclamation (BAMR) to perform this type of maintenance since they have the proper equipment to tackle it, but their in-house team could not make it out to the site. Luckily, the clog must have cleared itself and the AMD is once again flowing into the catch basin. MWA and BAMR are currently talking to a local private contractor who can regularly clean the pipes of Sagamore and other AMD treatment systems within the Indian Creek watershed, ensuring consistent functioning into the future.
A big thanks goes out to the trail users who reached out to us about the malfunctioning catch basin. If you suspect something is wrong at one of the AMD treatment systems, please contact us. The more eyes we have looking out for threats to our water quality, the better!