The Fracture Induced Electromagnetic Radiation: Approach and Protocol for the Stress State Assessment for Mining

This technical note portrays that one of the main reasons for the lack of progress in the application of the Fracture induced ElectroMagnetic Radiation (FEMR) method for the stress field assessment in underground conditions is the lack of a single measurement methodology/protocol. Three FEMR parameters (frequency range, intensity/sensitivity and activity) are analyzed in relation to micro-crack dimensions and rock elastic properties. Two seismic acoustic parameters (seismic moment and b-factor) are considered from the perspective of FEMR application in underground. It is proposed that the combined use of intensity, activity, b-factor and calculated seismic moment FEMR, together with the proposed FEMR instrument sensitivity and frequency range, be entered into the future FEMR measurement protocol as mandatory parameters for the FEMR instruments design for the successful assessment of the stress state in the vicinity of mine workings.