METHOD FOR THICK STEEP SEAMS MINING Russian patent published in 2006 - IPC E21C41/18 

FIELD: mining, particularly methods of underground mining.

SUBSTANCE: method involves separating seam into levels, driving sublevel drifts, which separate levels into sublevels; driving cross-drifts; weakening seam with hydraulic fracturing and excavating mineral in sublevels with several cuts; totally caving enclosing rock in goaf during second work performing and carrying over caved enclosing rock in underlaying sublevel goafs; cutting the second and next sublevels along with coal weakening in underlaying sublevel in advance of second workings equal to cut width. Height of above coal weakened zone is determined from mathematical expression based on weakened zone height, height of coal band, which is caved under its gravity and weight of caved rock during cut completion with the use of hydraulic monitor, and throw of working jet generated by hydraulic monitor.

EFFECT: reduced borehole lengths, decreased labor inputs, elimination the need of simultaneously performing mineral weakening works in upper sublevel parts and works in stope.

2 dwg