Eastern Oklahoma has a legacy of coal mining dating back to 1872. Since then, tens of thousands of acres have been mined and abandoned in the state, posing significant public health and safety hazards. In 1977, federal legislation established standards for controlling the effects of active coal mining. The Surface Mining Control and Reclamation Act (SMCRA) 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 help mitigate the safety hazards and environmental harms of abandoned mines.
The Oklahoma Conservation Commission (OCC) AML Reclamation Program contracted Trihydro to create a reclamation plan for the Oldham Abandoned Mine Land Reclamation Site. The plan addressed critical public safety issues in the state’s Shropshire Valley strip mines, targeting a former coal strip mine near Stigler, a small city in northeast Oklahoma, that presented two main problems: a 6.5-acre hazardous water-filled strip pit and a 3,450-foot dangerous highwall.
Trihydro partnered with Aerial Data Service to collect data using aerial photography, airborne LiDAR, ground control, bathymetric survey, digital mapping, digital orthophotos, and Unmanned Aerial Vehicle (UAV) photography and video of the site. The team used this data to assess existing site conditions and aid in developing the reclamation designs.
Trihydro’s comprehensive construction plans detailed the grading, cross-sections, and a stormwater pollution prevention plan for the project site, aiming for a safer and more stable landform. The team’s reclamation strategy involved infilling about 60% of the water-filled pit and reshaping the remaining highwall and spoil piles to create flatter slopes. The plan included a stormwater detention structure to control erosion and sedimentation during construction and to later serve as a water source for livestock. Trihydro also considered environmental effects on migratory birds, soils, wetlands, endangered species, and historical and archaeological resources in the area and included a plan to establish permanent vegetative cover to integrate the site with the surrounding topography.
The planning effort used geomorphically stable design principles informed by Carlson's Natural Regrade software to significantly reduce safety risks for the site's frequent visitors, including the landowner's young children and local hunters. Trihydro’s design for the Oldham Abandoned Mine Land Site would reclaim about 45 acres of land, enhancing public safety and environmental health near heavily used roads and populated areas. Construction of the reclamation design was delayed after the federal government stripped the State of Oklahoma of its regulatory authority over coal mining and abandoned mine reclamation throughout eastern Oklahoma’s Indian Country. Reclamation of the site continues under the authority of the U.S. Department of the Interior’s Office of Surface Mining Reclamation and Enforcement.