This paper evaluated stability of drives excavated in paste-filled stopes for drilling long holes for further blasting in underhand mining. The practical implementation of the process has been carried out at the Rampura Agucha underground zinc mine in India. Simulation for effect of excavation and blasting vibration on the surrounding area was carried out using dynamic analysis in 3 dimensions using FLAC3D. The actual geometrical profiles of the stopes along with the original rock mass properties were incorporated in the model. The stopes below the blasted stopes are prepared for ore extraction after excavation drives in paste fill. Rayleigh damping condition was applied to the model along with application of dynamic blast load with viscous boundary conditions. The vertical component of peak particle velocity (PPV) at various points in the model were measured and were compared to the values observed at the corresponding locations in the field.

1 Introduction

According to different mine conditions, mining methods are chosen to increase productivity. The activities are planned, however, by keeping the safety of personnel and equipment as a primary concern. The paper discusses the effect of vibration from blasting on mined-out stopes in the Rampura Agucha underground lead-zinc mine in India. The mining method applied is underhand mining method with paste backfill. To undergo underhand mining, the blast boreholes required to carry out blasting activities need to be drilled downwards from the crown level of the stope. Hence, paste filled drives are excavated by drilling and blasting operations. Vibrations generated from blasting affect the stability of the backfilled paste which has low strength compared to ore body or host rock. Therefore, it is necessary to ensure the stability of these drives until the drilling and blasting activities of the stope are completed. A similar method for underhand mining in India has not been implemented in the past.

This content is only available via PDF.
You can access this article if you purchase or spend a download.