ABSTRACT
Interaction effects of mining two contiguous coal seams in ascending order with filling, under two different conditions, have been presented. Thickness of the parting and gradient of the seams, were 4.0 T to 5.0 T and 1 in 1.8 respectively, in the first case and 2.5 T to 4.0 T and 1 in 5.6 respectively, in the second case, T being the thickness of extraction in the lower seam. The existing guidelines specify the parting thickness to be 10 T and 15 T, for seams steeper than and flatter than 1 in 3, respectively. Finite difference simulation of the mining environment, in both the cases, was carried out by FLAG (Version 2.27). Multistage extraction and simultaneous sand filling was incorporated and 56 models were constructed under different geomining conditions, for assessing the stability of the parting and upper seam workings. Calibration of the models against measured deformations was carried out to standardize the model for use under similar geomining conditions elsewhere.
