Abandoned Mine Lands Reclamation
Trihydro has supported the reclamation of several former surface coal mines in south central Iowa. To date, our team has developed the reclamation designs and successfully constructed five sites covering 235 acres.
Trihydro was selected by the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation and Water Quality, Mines and Minerals Bureau (Bureau) to perform field investigations, develop reclamation designs, and manage reclamation construction for several former surface coal mines in south central Iowa. To date, Trihydro has developed reclamation designs and constructed five sites identified as the Teach AML (30 acres), Vanderbeek-Langstraat AML (46 acres), Rowley AML (24 acres), Waechter AML (78 acres), and Jager AML (57 acres). The sites cover 235 acres of former coal strip mines, which include polluted waters, water-inundated pits, vertical high walls, large spoil/overburden piles, and clogged streams. Trihydro has completed designs for three additional sites, Roe AML (30 acres), Klootwyk AML (109 acres), and North King (55 acres), and is currently managing the construction of Vanderzyl AML (66 acres). Trihydro has also assisted the Iowa AML program on the DeRonde and Pleasant AML sites for design assistance and review.
Trihydro performed site investigations at each site to document and assess the conditions and hazards associated with site features. Feature mapping, aerial photos, LiDAR topographic mapping, ground-based topographic mapping, and digital photos were collected during field investigations and compiled into a web-based project management portal with a site-specific GIS application. Trihydro developed conceptual, preliminary, and final reclamation plans for review by the Bureau and landowners. To aid in developing the site plans, natural resource surveys and a geotechnical investigation (at the Teach site only) were performed to identify potential Waters of the U.S., wetland areas, water quality, depth of spoil material, and surface soil composition. The investigations included wetland delineations, geotechnical drilling, surface water sampling and analysis, existing structures inventory, and desirable tree species surveys.
The final reclamation designs for the sites incorporate geomorphically stable design concepts using Carlson’s Natural Regrade software and more traditional terrace and down-drain designs. The Teach site was Iowa’s first AML site to be designed completely using the geomorphic grading approach in Iowa. Trihydro prepared final construction plans and specifications, developed construction estimates, prepared bid documents, conducted the pre-bid meeting and tour, and assisted the Bureau with bid adjudication. Trihydro and the Bureau coordinated with the landowners and the U.S. Army Corps of Engineers (USACE) to develop designs that provided for the abatement of the polluted drainages from the areas as well as eliminated the recognized public safety and other environmental concerns present at the sites, while mitigating disturbances to wetlands and waters of the U.S. Trihydro also provided construction management and performed part-time, on-site construction monitoring during construction of the projects.
