The test results show that the drawing interval of 1.5 m is helpful for controlling dead-unconsolidated thin sandstone of coal seam roof and reduce sand ratio of drawn top-coal.
英
美
- 试验结果表明,放煤步距采用三采一放有利于控制顶板极松散细砂岩,降低放出顶煤的含砂率。