Assessment on the hydrogeological condition of an open pit mine based on piezometric measurements

Abstract

Understanding groundwater and flow pattern behavior in a given mine site is generally based on accepted theory related to flow through porous granular media. The existence of discontinuities within the rock mass alters the accepted hydraulic behavior being the joint profile and aperture variability a challenge when designing an open pit mine. In this regard, groundwater interaction with the rock mass is the key variable that influences mining slope design and monitoring. This manuscript studies and analyses the geotechnical perspective of an open pit mine and carries out a comprehensive assessment on the groundwater behavior of an open pit mine in a hard rock environment. The analysis is carried out using data gathered from piezometers and correlating the findings with the structural model of the mine. A comparison of the analysis with the results of previous investigations like hydraulic testing and mapping of the mine site are presented comprehensively. The authors propose the concept of receding time for a better understanding of the drainage capability of a given discontinuity (or a set of them) and its importance in assessing groundwater behavior of the pit slope. Discussions are also made on how groundwater flow can be locally modified by slope scale structures and what are the potential consequences there may have for overall slope stability.