CASE STUDY: GEOMORPHIC RECLAMATION OF ABANDONED COAL MINES NEAR RATON, NEW MEXICO DESIGN AND CONSTRUCTION OVERSIGHT

Abstract

In order to address hazards and environmental detriments associated with historic coal mining, the New Mexico Abandoned Mine Land Program contracted with Water & Earth Technologies, Inc. Construction for the Swastika Mine and Dutchman Canyon Reclamation Project took place over a six-month period in 2012. The geomorphic reclamation approach coupled hydrologic and hydraulic engineering analyses with geomorphic design tools to stabilize and reclaim the significantly altered landscape. Coal waste piles, a straightened and incised half-mile-long reach of the Dillon Canyon stream channel, and existing wetland features proved to be challenging design elements of this award winning project. The geomorphic landform accommodated nearly 200,000 cu. yds. of coal waste that had been abandoned in unstable piles that were degrading the adjacent stream physically and chemically. The stream reconstruction restored meanders and a functional floodplain to the impaired system. In Dutchman Canyon, road and embankment improvements were designed to allow seepage from closed mine adits to hydrate a constructed salttolerant wetland. In addition to the geomorphic landform and the sinuous stream, a realigned access road was constructed through the narrow valley. Valuable ecological and cultural features including mature trees, wetland areas, utility poles, and over 200 identified archaeological features were preserved. Geomorphic designs were modified as required during construction to accommodate additional archeological discoveries. Geomorphic design was accomplished using Natural RegradeTM with GeofluvTM to incorporate stable drainage and topographic variety into the reconstructed stream and landform. The design used geomorphic criteria developed from measurements of nearby, undisturbed portions of the valley, mimicking stable landforms and stream characteristics that have developed naturally in response to the topographic relief, soils, vegetation, and climate in the project area. The project created an aesthetically pleasing valley with an ecologically rich riparian corridor integrated into a stable landform composed of reclaimed coal waste. Additional