When diesel powered trackless transportation equipment causes serious underground air pollution, Which of the following option can be considered?( ) A: Electricity B: Wire rope C: Winch D: Gasoline

What are the disadvantages of ramp development method?( ) A: Large amount of development work B: Trackless equipment has large initial investment, heavy maintenance workload and high technical level requirements C: The development depth is restricted by driving technology and economic factors D: No steel is required