Electric Resistivity Variations of Rock Formation at an Abandoned Mining Shaft Site

Abstract

Abandoned shafts, even if backfilled, create a potential hazard for the envi-ronment and safe use of post-mining lands. The hazardous

phenomena depend on the shaft tube structure and the extent of mining activity in the vicinity and, on the other hand, the dynamic processes which occur

within rock strata. Among the processes which affect the rock mass structure is the rainfall water migration and erosion. The amount and rate of water

flow within soil and bedrock in the specific area depend on time. The water saturation in rock formation is the main factor which determines the

electric properties of geological environment. These phenomena can be used for monitoring erosion processes by electroresistivity or conductometric

measurements. In the paper, experimental results of the tests car-ried out in an abandoned shaft site are described. The tests were performed in three

series of measurements conducted using vertical electroresistivity sounding method (VES) in autumn, winter and spring. The results indicate significant

changes of rock formation resistivity values due to change in seasonal condi-tions. This impacts the interpretation of the data collected in

geoelectrical meas-urements.