Investigation of LTCC Efficiency in Horizontal and Near-Horizontal Thick Coal Seams with a 2D Physical Model

In this study, the effects of coal seam slope, caving height and top coal drawing interval parameters on longwall top coal caving (LTCC) efficiency in LTCC applied in horizontal and near-horizontal thick coal seams were investigated. In addition to these researches, in the study, the relationship between top coal loss and rock mixture ratio, which are important disadvantages of LTCC, was evaluated and the importance of these parameters for LTCC was emphasized by determining the critical top coal loss and critical rock mixture ratio. As a research method, physical models that are effectively used in researching caving mechanism problems were used and a 2-dimensional physical model was developed for the study. The development processes of the physical model, test material selection processes and the suitability of the physical model are explained in detail in the study. A total of 47 physical model tests were carried out in the research. Test results showed that the caving height and top coal drawing interval are effective on the rock mixture ratio, the top coal drawing interval is effective on the top coal loss, and the caving height and coal seam slope are effective on the amount of top coal drawing. In addition, the study results showed that the relationship between top coal loss and rock mixture ratio is an important relationship for LTCC efficiency under all conditions, and the importance of critical top coal loss and critical rock mixture ratio for LTCC was revealed.