Abstract: An explosive displacing bore hole tube is formed by an elongated tubular member having opposite ends thereof closed, as by caps, to enclose a nonexplosive material within the tube. The nonexplosive material is preferably nonpressurized air; bore hole cuttings or other material may be added for ballast. Alternatively, the tube may be completely filled with such cuttings. The explosive displacing tube is positioned within a bore hole along with a bulk flowable explosive to reduce the volume of explosive at a selected location or locations along the bore hole to thereby reduce the blast intensity at such a location or locations when the explosive is detonated. A tube filling apparatus is provided for simultaneously placing ballast in a plurality of the tubes.