Enhanced Surface Mine Reclamation Using Geomorphic Landform Principles

Approximately 40% of operating mines in West Virginia are surface mines, producing approximately 50 million tons of coal annually. Traditional surface mine techniques include end-dumping burden material removed from the surface into nearby valleys, resulting in valley fills with uniform slopes, terraces, and drainage ditches. These techniques provide the opportunity for improvement in the areas of stream loss, surface water infiltration and runoff, and downstream water quality. The objective of this research was to create alternative surface mine reclamation designs for a permitted valley fill. Four designs were created: i) dendritic drainage; ii) retrofit; iii) dendritic drainage with bench ponds; and iv) dendritic drainage with valley ponds. All designs were based on a permitted surface mine site (1.4 km²) in southern West Virginia. Characteristics such as stream length and cut/fill volume were compared among the four created designs, the traditional design, and the original pre-mined surface. Geomorphic landform principles including creating landforms with overall hydrologic balance were applied to the design permit area. The geomorphic landform design (GLD) resulted in approximately 5.3 km of created channel length, 5.7 x 107 m³ of fill material (same volume cut during mining), and was comprised of ridges, valleys, and channels. The same design principles were applied to the top surface of the traditional valley fill to create the retrofit design. The traditional valley fill (6.9 x 107 m³ volume) consisted of a level top surface with drainage ditches around the perimeter. Features of the retrofit GLD included complex slope profiles and a dendritic drainage pattern. The design resulted in 6.7 x 107 m³ of cut volume and 5.7 x 107 m³ of fill volume and approximately 8.4 km of stream length. The GLD design surface was used as the base for the surface water retention designs, which included a design with three bench ponds and one with three valley ponds. The bench pond structures mimicked wetlands and were located beside the GLD channels. The bench pond design resulted in approximately 5.3 km of channels and required 5.7 x 107 m³ of land to be cut and 5.7 x 107 m³ of land needed as fill material. The valley pond structures mimicked dams and were located directly on the GLD channels. The structures blocked and retained surface water runoff that was traveling downstream in the channels. The valley pond design created 5.3 km of channels and required 5.7 x 107 m³ cut material, but required nearly 5.7 x 107 m³ of fill material. All four enhanced surface mine reclamation designs provide enriched alternatives to traditional valley-fill techniques and improvements for previously constructed valley fills. These improvements could revolutionize valley fill design using geomorphic landform principles and possibly include surface water runoff retention structures to promote animal and vegetation diversity. Features of these designs include created stream channels, improved surface water control, and topography creating a natural appearance.