converging-diverging slot-shaped hole
Fan shaped medium length hole
slot-shaped forward flared hole
C-shaped and L-shaped flap
sand shaped and mixed shaped alumna
single U shaped and double U shaped vertical borehole
A shrinkage method combining with medium-length hole and shallow hole
electron-hole liquid drop (=electron-hole droplet)
hole by hole blasting technique
hole by hole detonating
hole by hole initiating