INFLUENCE OF THE DESIGN OF BLASTING WELLS TAMPING ON REDUCING THE YIELD OF OVERSIZE ROCK MASS MATERIAL

Abstract

The paper contains the requirements for tamping the
blasting wells. The Pacific State University has made a
search for structures of blast hole faces that would
meet these requirements and considered the most successful solutions. For tamping wells with smooth walls,
a spacer design has been developed, which is a hollow
split cylinder with a spacer cone inserted into it. Experimental field tests and industrial tests of spacer
tamping have shown that they can lock explosive wells
up to camouflet, but high pressure and temperature require making them from steel. They are expensive to
manufacture, and they can get into the mouth of the
crusher together with the rock mass.
For wells with fractured walls, a tamping in the form
of a monolithic concrete cone has been developed. The
well cavities around the tamping and above it up to the
mouth is to fill with coarse aggregate mixed with finegrained material for gas tightness. Experimental landfill tests and industrial tests of such design have shown
that they can lock explosive wells up to camouflet, however, concrete cones have a large mass, especially
when drilling large diameter wells, this can limit their
use. In order to combine the advantages and eliminate
the disadvantages of the considered tamping designs, a
combined tamping is proposed in the form of a cone
made of an elastic material, such as vulcanized rubber.
The cone in the upper part is made monolithic, and in
the lower part – hollow with longitudinal sections in
the form of petals. Providing a long-term closure of the
charging cavity until the wellhead is destroyed, this
plugging contributes to a more complete flow of secondary reactions in the detonation products and, accordingly, increases the energy of the explosion.