An economic evaluation of soil bioengineering as a method for slope stability on abandoned mine land in Eastern Kentucky

Unstable slopes are a serious problem on abandoned mine land (AML) in Kentucky and a number of other states. Current practices used to manage unstable slopes rely on modern conventional techniques that incorporate rock, concrete, or steel structural components. Implementation of these techniques has proven expensive due to recurring maintenance requirements. This study examines soil bioengineering technology as a viable alternative. In this study, the cost effectiveness of two common slope stabilization systems-rock gabions and rock riprap-has been compared with the innovative soil bioengineering system. Baseline cost estimates applied to all three systems were consistent with commercial scales. Assuming a useful life of 20 years for both the gabion and riprap systems, sensitivity analysis using net present values (NPV) in response to changes in both installation costs (I) and useful life (N) was conducted on both systems. Data was calculated over a range of applicable interest rates. The resulting values were compared to installation costs for the soil bioengineering system. This analysis confirms that soil bioengineering technology can be economically competitive with its conventional counterparts. Further, it is hoped the results of this study can lead to wider acceptance of environmentally conscious slope stabilization systems in mining regions throughout the country.