Comparison of model study with field implementation of gravity blind backfilling method to control subsidence induced disaster in abandoned underground coal mines

Blind hydraulic backfilling technique is used for subsidence control in underground coal mines. A laboratory size model of underground working was developed to understand backfilling process. Observations from model were utilized for backfilling process in one of the underground mines. This study describes the results obtained in the field investigation at an old abandoned waterlogged underground coal mine of Eastern Coalfields Limited (ECL), a subsidiary of Coal India Limited and their verification with the findings obtained in the laboratory scale model study carried out on a model of underground coal mine worked by board and pillar method. The relative influence of slurry concentration and flow rates on the areas of filling from a single inlet borehole has been discussed. The relative spread of sand in different directions has also been measured using a remotely operated underground vehicle mounted camera. The empirical relationships developed under field conditions have been found to be similar to those of laboratory model.