Geotechnical Properties and Flow Behavior of Coal Refuse under Static and Impact Loading

Abstract

Fine refuse from coal processing is frequently disposed of as slurry in an impoundment supported by an embankment consisting of coarse refuse. Flow failure of coal-waste impoundments and metal-tailings dams under static and dynamic impact loading has occurred many times in the last few decades in the form embankment or dam instability or breakthrough of impounded coal-waste slurry into underground mines. Such failures can release huge amounts of flowable waste and cause severe property damage, loss of life, and significant environmental degradation. Until recently, there has been no comprehensive study reported on the properties and flow behavior of impounded coal refuse. In this study, laboratory experiments were performed on samples collected from the Appalachian coal field to measure the geotechnical properties of fine coal refuse. A comprehensive investigation was carried out on the flow behavior of impounded fine-coal-refuse slurry under static and impact loading by using a group of small-scale and centrifuge model tests. The relationships between water content and important parameters in flow behavior were established, and the flow behavior of slurry with different water contents was analyzed under static and impact loading. In addition, the employment of slurry cells as a potential countermeasure to flow failure was evaluated in centrifuge model tests.