Evaluation of pre-jamming indication parameter during blind backfilling technique

Hydraulic blind backfilling is used to reduce subsidence problems above old underground water-logged coal mines. This paper describes experimental research on a fully transparent model of a straight underground mine gallery. An automatic data acquisition systemwas installed in the model to continuously record the sand and water flowrates along with the inlet pressure of the slurry near the model's inlet. Pressure signature graphs and pressure loss curves with bed advancement under different flow conditions are examined. Pressure signature analyses for various flowrates and sand slurry concentrations are conducted to evaluate a pre-jamming indication parameter, which could be used to indicate the arrival of the final stage of filling.