METHOD TO SEAL ANTI-FILTRATION SCREEN UNDER WATER RESERVOIR AFTER PIT DEPLETION Russian patent published in 2015 - IPC E21B33/00 E21C41/00 

FIELD: construction.

SUBSTANCE: into a lower part of the already created antifiltration screen containing doleritic rocks, they pump cement mortar on the basis of sulphate-resistant or aluminous cement with 2% additive of calcium chloride under pressure of 0.7-0.8 MPa exceeding hydrostatic pressure, via wells drilled from underground mines. Maintain until hardened. After hardening the created rock-cement layer of the antifiltration screen and the upper part of the ore block are additionally plugged with local injections of gelling compositions GALKA® under pressure of 0.5-0.6 MPa, which is below fracture pressure of the ore safety block thickness left under the antifiltration screen. The gelling composition GALKA® has the following ratio of components, wt %: aluminium salt 5-15; carbamide 20-35; urotropine 3-10; water - balance.

EFFECT: increased strength and reinforcement of antifiltration properties of a screen when filling a pit for safe performance of underground mining works.

4 cl, 3 dwg, 1 tbl