Study of in-situ sieving experiment and gradation optimization of gangue

The anti-compression capability of gangue affects the controlling effect of coal mining with gangue backfilling obviously. Meanwhile, the anti-compression capability of gangue depends on their gradation characteristics. Taking the filling gangue of backfilling mining face No. 1603 in Jisan coal mine as a case study, an in-situ experiment is conducted with the gangue of underground mine by sieving method, and the composition characteristic of the gangue is obtained. Based on this, gangue gradation is optimized by continuous gradation theory. The result shows that 1) the original gangue has a clear gradation flaw: with a high content of large-sized particles and a low content of small-sized particles; 2) the gangue after continuous gradation has a better anti-compression than original ones; and 3) when the index of Talbol formula is 0.4, the anti-compression capability is the best, with an increase of 21% compared to the original gangue.