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Highwall mining technology is the modified version of earlier auger mining. It facilitates recovery of locked up deposit in open pit highwalls, below villages, road, and other surface structures. Mining operations consist of driving series of parallel roadways at intervals in a planned way to recover considerable amount of coal from the highwall. The method offers great safety to mining personnel because of remotely controlled highly mechanised mining operations and unmanned extraction drivages. Although key to successful operations is scientific design of web pillars that support these drivages, optimum design to increase recovery is the main requirement. Design methodology includes estimation of long and narrow pillar strength through CIMFR empirical equation with some modification and application of numerical simulation to consider multi-seam interaction, pillar stress, etc. This methodology' has been utilised for highwall mine design at Opencast Project II (OCP-II) mine of Singareni Collieries Company Limited (SCCL) and Medapalli OCP (MOCP) of SCCL by CIMFR. Although, mining operations at both the sites are successful, performance analysis reveals that ooccurrence of roof fall, breakdown on account of geological disturbances and poor power supply, exposure of stone bands in the seam, working in cross gradient, etc., are some of the issues that has jeopardised full production capacity of the CHM. The highwall mining design methodology and performance analysis at couple of sites are discussed in detail in this paper. [ABSTRACT FROM AUTHOR]

High-wall mining, an extension to open cut mining, commonly use auger and continuous highwall mining system. Rock properties and structural geology' of rock are the vital parameters for designing highwall mining. The limitations of basic equations/models developed for computing web and barrier pillar strength, geological conditions and improper execution of highwall mining are the key causes for instability of highwall. Meticulous monitoring of displacement rates is imperative to evaluate the stability of the highwall and, in turn, safety of men, material and machinery. There are several land based, airborne and satellite based techniques of highwall movement monitoring systems. Frequency of measurement depends on the rate of ground movement. Total station can be used for daily monitoring whereas slope stability radar can be adopted for continuous monitoring if required. A study was conducted at OC-II of Singerani Collieries Company Ltd. by Total Station. The safe limits of highwall stability in terms of strain are discussed in the paper. [ABSTRACT FROM AUTHOR]