采矿：地面的防护
mining: protection of surface
采矿CAD
mining CAD
CAD system used in mining industry
采矿方法联合应用
Mining method combined application
采矿方法选择
Selection of mining method
Mining method selection
采矿方法优化
Optimization of mining method
Mining method optimiza-tion
Mining method optimization
采矿方法优选
optimizaiton of mining method
Optimal selection of mining method
Optimal choice of mining method