<正> The effective diffusion coefficients in mine ventilation-flows had been obtained as 4 to 200 m~2/s by matching the measured concentration-time curves with
<正> The difficulty of selecting appropriate rheological model and parameters for the alternating distribution of soft and hard rock layers was often encountere
Roadway surrounding rock is a compound structure consisted of roof, floor and sides. The sides of extraction opening is the weak coal mass, which affect immedia