More than 15,000 abandoned mine features are believed to exist in New Mexico. These features range from shallow prospecting pits to deep mine shafts that can pose significant public safety risks. In 1977, federal legislation established standards for controlling the effects of active coal mining. This law, the Surface Mining Control and Reclamation Act (SMCRA), also created a trust fund generated from fees on active coal mining to pay for the reclamation of abandoned mines that endanger the public. Trihydro has worked with several state Abandoned Mine Land (AML) Reclamation programs, which use funds from SMCRA to address the safety hazards and environmental harms of mines abandoned before the enactment of the federal law.
Trihydro worked for the New Mexico AML program to develop design specifications, plans, and a cost estimate for the Boston Hill Mine Safeguard Project — an initiative in Silver City, New Mexico that aims to identify and put in place solutions to protect the public from local abandoned mine hazards.
Trihydro and its project partners collected aerial imagery and topographic survey data for an approximate 1,190-acre area encompassing the Boston Hill Open Space in southwest Silver City. This data enabled the Trihydro team to identify about 510 abandoned mine features in the original project area, including shafts, adits, pits, and open stopes across city, Bureau of Land Management (BLM), and private lands.
The team inspected these features during the investigation and reconnaissance phases of the project, developing an electronic field form using the ArcGIS Field Maps program to support the process. After evaluating the features, Trihydro prioritized reclamation based on accessibility, fall potential, and trail proximity.
The team provided the New Mexico AML with a comprehensive ArcGIS database containing data points previously collected by the New Mexico AML, BLM, and their contractors, in addition to updated feature coordinates, descriptions, reclamation recommendations, and photos that Trihydro’s team had gathered. The combined inventory allows the client to work with one database going forward.
Because of the New Mexico AML’s funding constraints, Trihydro worked with the client to re-scope the project. The project area consequently decreased, but the ArcGIS database includes information about features that Trihydro assessed in the original project area. This inventory will help the New Mexico AML keep track of features that were cut out in the updated project scope.
Trihydro ultimately delivered plans, specifications, and a cost estimate for reclaiming 46 abandoned mine features in New Mexico. The plans included various safeguards, such as waste rock mortar closures, steel mesh closures, metal grate closures, adit and stope metal grate closures, and egress adit closures. The team also outlined access and haul routes for contractors.
The New Mexico AML hired a contractor to implement Trihydro’s plan. Reclamation of the abandoned mine features that Trihydro assessed is now complete.