METHOD TO EXTRACT MATERIALS FROM THICK UNDERGROUND FORMATIONS Russian patent published in 2012 - IPC E21C45/00 

FIELD: mining.

SUBSTANCE: method to extract materials from thick underground formations is carried out by means of formation opening with a well, placement of a well hydraulic monitor unit in it, creation of a naturally balanced vault above a production chamber within the productive horizon and washout of formation rocks with pulp delivery to the surface. In order to increase efficiency of well hydraulic production of minerals, excessive pressure is pulled in the production chamber, which meets the following condition: P_chamb.≥P_form.+0.03 MPa, where: P_chamb. - pressure of working fluid in the production chamber, P_form. - formation pressure. At the same time the pressure in the chamber is continuously monitored with sensor installed in lower and upper parts of a movable pipe of the hydraulic monitor unit, and the excessive pressure in the production chamber is provided by control of the working fluid supply into the well, with high-quality of hydraulic insulation of the annular space with mortars based on bentonite powders with specific viscosity from 50 sec. until "non-liquid" state.

EFFECT: higher efficiency of well hydraulic production of minerals.

2 cl, 1 dwg