DOWN-HOLE STEMMING Russian patent published in 2012 - IPC F42D1/20 

FIELD: mining.

SUBSTANCE: down-hole stemming is made from flexible polymeric material, has the shape of the cylinder the outer diameter of which is equal to the well diameter, axial inner diffuser that has the shape of elongated hemisphere joined with truncated cone. Diffuser walls are as thick as cylinder walls and made from the similar material, the space between cylinder and diffuser is filled with inert material, for example, sand. In the lower part of the stemming there installed is a diffuser cover with hole for means of initiation.

EFFECT: preservation of the whole diffuser surface area at reflection of shock waves.

2 cl, 2 dwg