Abstract: An inflatable air tube includes a sleeve member arranged concentrically about the upper end portion of the air tube to define a receptacle chamber for receiving a quantity of bulk explosive blasting powder, thereby to add weight to the air tube for positioning and stabilizing the same in the bulk explosive powder during the depositing of the powder into a blasting hole drilled into the ground. According to the method of the present invention, a plurality of accurate blasting patterns may be provided in the blasting powder column by timing the manual or mechanical insertion of the air tubes into the bulk blasting powder relative to the rate of supply of the powder from a source thereof.

Abstract: A solid column explosive charge method for blasting rock includes a hollow gas-filled core component arranged collinearly in concentrically spaced relation within a vertical borehole, the core component being seated upon a first layer of particulate explosive material, and a first annular portion of the particulate explosive material being arranged concentrically about the core component. The first layer and the first annular portion are in engagement to define a continuous explosive column. A plurality of core components together with associated layers and annular portions of the explosive charge may be arranged in a continuous vertical column, the total volume of the core components being from 10 percent to 25 percent of the volume of the explosive column. A top layer of inert fill material is arranged above the core component to close the upper end of the bore opening.