Measurement and prediction of internal stresses in an underground opening during its filling with cemented fill

Knowledge of the internal stresses of cemented fill used in underground mines is very important with respect to ground control. The stope of a Canadian gold mine was instrumented with earth pressure cells to measure the stresses within the pastefill during and after filling. The results indicate that the stresses increase during backfilling but tend to decrease after the completion of backfilling. The Longitudinal stresses were observed to be the highest, while the vertical and transverse stresses were lower and roughly equivalent. Two new 3D models are proposed to predict the internal stresses of pastefill and the pressure on barricades as a function of the filled height. These 3D models have been extended to take into account the time factor in the development of stresses within pastefill. Comparison of the model responses with experimental data indicates that the models predict the stresses within the pastefill and the pressure on the barricade with reasonable accuracy.