Numerical Modelling and Monitoring of Slope Movements Vis-À-Vis Development of Trigger Action Response Plan For Opencast Coal Mines

Abstract

This paper presents the application of recent guidelines of Directorate general of Mine safety in January 2020 for a typical coal Opencast mine. TARP suggested for the opencast coal mine is demonstrated with reference to the typical geo-mining conditions and recent data during this typical COVID19 period from opencast coal mine on monitoring the movements and numerical model studies for design of stable dump slopes and high wall slopes along with sensitivity analysis on effect of ground water. Development of proper TARP suitable for the geo-mining conditions of any opencast mine with observational approaches and meticulous monitoring and online interpretation and communication to the grass root level. Indian mining industry has recently witnessed the biggest slope stability disaster involving 23 persons under slope failure in the year 2017. Adopting a suitable TRAP will lead to self-reliant and sustainable practices with improved safety and stability of slopes. The analyses of factor of safety of slopes for existing slopes are found to be within prescribed safety limits. The monitoring results up to 20 June 2020, revealed the overall stability of dump slopes with practically considerable vertical displacement within 12 mm on the dump-A. However, these local movements observed from the Total Station reading is due to high moisture content of materials and deployment of HEMM near to the monitoring stations for the formation of benches in dump. The maximum horizontal movement at any station is within 14.5 mm across 19 days indicating a daily movement of 0.76 mm which is far below the critical limit proposed by various researchers, and hence the slope is considered stable. Further analysis may be carried out in future for the Mine A with a large scale monitoring data to obtain an insight of slope movements.