Trihydro and its predecessor, Alloy Group’s Engineering and Consulting Division (acquired in 2024), provide environmental services for a large, complex, legacy mining site in the San Juan Mountains of Southwest Colorado. The site faces a multitude of challenges. Extreme winter weather with blizzards and avalanches creates significant safety hazards and logistical difficulties. Furthermore, the site borders a high-quality trout stream and extends into a neighboring mountain with its own mine workings, requiring careful environmental management to protect the surrounding ecosystem. Adding to the complexity, an adit located on the site discharges water with seasonal flow variations ranging from 600 to 1,300 gallons per minute (gpm). High concentrations of metals are present in the mine water that drains to the adit.
Due to environmental concerns, regulators and stakeholders were seeking viable passive treatment solutions for numerous abandoned mining sites. Trihydro addressed this need by operating two demonstration-scale passive water treatment systems, treating a combined flow of approximately 610 gallons per minute (gpm).
Passive treatment offers a distinct advantage over conventional methods. Passive treatment utilizes naturally occurring elements and biogeochemical environments to remove metals from mine water. This translates to less reliance on external energy sources, chemicals, and manpower for operation.
Trihydro diverted the adit water through a series of ponds to determine the optimal passive treatment system for the adit water. These engineered ponds include both horizontal and vertical flow wetlands. Native plants and various organic materials are used within these wetlands to create a biogeochemical environment ideal for metal removal. This process involves sulfate-reducing bacteria, which generate sulfide that binds to dissolved metals and creates alkalinity, raising the overall pH level of the water. Notably, the only active steps in the entire system involve initial aeration and the addition of a coagulant.
The demonstration systems are equipped with instruments connected to remotely accessible data loggers and a Supervisory Control and Data Acquisition (SCADA) system for continuous monitoring and control.
Trihydro designed a full-scale passive water treatment system based on the data gathered from the demonstration-scale systems. Construction of the full-scale system is underway.
Beyond water management and treatment, Trihydro's role encompasses comprehensive site operations, maintenance, and monitoring. This includes groundwater and surface water monitoring and sampling, stormwater management, settling pond monitoring and maintenance, and site maintenance (such as access road maintenance, fencing repair, etc.).
Trihydro also plays a crucial role in designing, overseeing, and implementing improvements across the site. The project team comprises process engineers, civil engineers, environmental engineers, geochemists, geologists, health and safety experts, and field technicians. These specialists bring a wealth of expertise in areas like process and environmental engineering, civil engineering and design, bench and pilot-scale testing, operation and maintenance implementation, construction oversight, and health and safety management.