矸石不出井
waste not discharged from mine
矸石充填
filling with refuse rock
stowing with refuse
refuse filling
gangue backfilling
coal refuse backfilling
backfilling with coal rejects
waste filling
gangue packing
gangue filling
矸石井下处理
underground disposal of waste
矸石氧化淋滤水
oxidation-leaching waste water
矸石直接充填采煤
the coal mining with gangue backfilling
矸石直接充填采煤方法
coal mining with raw waste backfilling method
矸石制砖
making brick from coal deads