Semester

Spring

Date of Graduation

2023

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

John Quaranta

Committee Member

Leslie Hopkinson

Committee Member

Paul Ziemkiewicz

Abstract

Coal refuse impoundments are the primary storage facility used in the mining industry for the placement and dewatering of fine coal refuse. The West Virginia Department of Environmental Protection (WVDEP) promulgate prescriptive impoundment closure and requirements for the long-term breach and reclamation of the facilities. Typical impoundment reclamation designs consist of backfilling the impoundment with coarse coal refuse and placing soil cap with a minimum 2% slope to the perimeter drainage ditch. Geomorphic landform design (GLD) promotes long term stability of a regraded structure through simulating local topography. By balancing the hydraulic response of the site, runoff and erosion can be mitigated. Of these GLD models, the subsequent factors of safety must be determined and documented with the use of PLAXIS LE. PLAXIS LE is a finite element modeling (FEM) software for geotechnical engineering, such as slope stability, consolidation, groundwater, and dynamic conditions.

The objectives of this research were: 1) coal impoundment site evaluation of active and reclaimed sites, 2) FEM of a reclaimed coal refuse impoundment with design alternatives to the site layout, and 3) incorporating findings from Objective 1 and 2 into a GLD based impoundment closure study of an active coal refuse impoundment to promote long-term stability and reduce reclamation costs for future closure. Through contact with the WVDEP, six reclaimed refuse impoundments, one active freshwater impoundment, and one active impoundment were visited to observe site conditions. The findings of this research determine that GLD applications for impoundment closure and reclamation reduces infiltration and promotes runoff. Complex geometry and limitations to the GLD created profile must be reviewed to ensure slope stability. Based on current reclamation guidelines and standard reclamation practices, GLD is not itself a recommended approach for impoundment closures, but aspects of the design method may be relevant to reduce saturation issues driving soil strength reduction and long slope lengths promoting infiltration.

Download

Share

COinS