Microgravity estimation of the safety hazard for ground surface due to the unfilled old mining shafts

Authors: Z. Fajklewicz, J. Radomiński

In the paper the theoretical and experimental results of the microgravity research are presented.

The mean goal of this works were to applied the microgravity measurements for detection of the old unfilled mine shafts.

The next stage of the work was to find the relation between the shaft's parameters, density of material probable used to fill in the shaft, density of the microgravity points of the gravity pictures.

The are presented three examples of application gravity method for estimation of the stage of filled in of the shafts.

The shafts come from different areas of mine region. The first example is related to, shaft Rubin located in Piekary Śląskie.

The negative extreme of the residual gravity microanomalies is presented on Fig. 5. It is near by the gravity point no 9 and derives from old compressed old shaft so is confirmed by georadar measurements (Fig. 7).

The picture of the microgravity anomalies presented on Fig. 8 corresponds to unfilled old shaft Maria-Anna. On the base of gravity data it is possible to estimate of the hazardous area and state of the ground surface due to existence of the unfilled shaft.

The distribution of the microgravity anomalies in profile (Fig. 10) presents the negative anomaly over the air-shaft I in coal mine Saturn-Czeladź.

The negative gravity anomaly over the shaft corresponds to unfilled shaft with dilatation below the concrete plate over the shaft.