What is the requirement for coal-rock division when dividing steps?( )
A、Coalandrockareclassifiedintodifferentsteps;
B、Coalandrockaredividedinthesamestep;
C、Whethertherockishardorsoft,itshouldbeonthesamestep;
D、Coalandsoftrockareonthesamestep
发布时间：2025-08-22 05:04:47
