Geophysical signs of hard rock disturbance

Abstract

Introduction. Development of deep open pits requires reliable knowledge on conditions of rocks at the hard rock mass to locate potentially hazardous sectors which have considerable impact on efficiency and rationality of a deposit’s development. Definition of disturbed zones at the open pit benches is an actual scientific and practical task in terms of supporting stability and functionality of such facilities. Research aim is to study geophysical signs of disturbance of hard rocks by data of nondestructive ground-penetrating radar (GPR) observation of the surrounding rock mass at the working open pit benches in order to estimate their geological structure and differentiate by disturbance degree. Methodology. Nowadays, GPR data is overwhelmingly interpreted based on comprehensive analysis of amplitude, frequency and phase characteristics of an electromagnetic signal and without an attribute analysis of the wave field. When using the structural approach, based on the analysis of the dynamic and kinematic characteristics of the wave field, to identify hard rock disturbance areas, it becomes possible to significantly increase the accuracy of their determination and localization according to the nondestructive subsurface GPR research. Results. Based on GPR measurements, the author has studied geophysical signs of disturbed rock zones identification at the open pit benches which consist in a quantitative estimation of change in reflection response amplitude characteristic, permittivity of a section and Q factor attribute. Conclusion. Using the established relationships with the proposed analysis of geophysical signs, the GPR study data can contribute to the adoption of differentiated and providing greater stability parameters of benches and mining operations.