Radon Monitoring for Observation of Displacements in Rock Mass in Underground Mineral Mining
T. Sh. Dalatkazin, P. I. Zuev
Institute of Mining, Ural Branch, Russian Academy of Sciences, Yekaterinburg, Russia
Keywords: Undermined rock mass, stress-strain behavior, radon, thoron, emanations, modern geodynamics, prediction, safety
Abstract
The study focuses on the urgent problem connected with the improvement of prediction reliability for hazardous ground surface deformations in undermined areas. Conventional geodetic surveys not always allow early detection of signs of unexpected failures. The authors propose an approach to the improvement of geodynamic diagnostic procedure using radon emanation survey. The method involves the analysis of spatial distribution of radon isotopes (²²²Rn and ²²⁰Rn) in soil air, dependent on change in the stress-strain behavior of soil. The pilot study of the procedure was carried out on a site of the Sarany deposit of chromite ore, nearby the zone of the 2013 sinkhole. In the course of areal shooting along four profile lines, the volumetric activity of radon-222 and thoron was measured. Using the compression and tension values calculated from the data of radon monitoring and normalized radon activity, the maps of deformation and geodynamic zoning were plotted. The comparison of the research findings and geodetic survey results proves informativity of the proposed method for the stress-strain analysis of rock mass, and validates its application for the enhancement of mining safety. The new approach to interpretation of emanation survey data provides information on the stress-strain characteristics of rock masses.
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