Abstract: The present invention relates to a downhole-hammer drill-bit assembly for removable attachment to a substantially tubular casing of a downhole hammer. The drill-bit assembly has a substantially tubular chuck, a drill-bit, and a substantially tubular retainer. The chuck has a step. The drill-bit has a bit shank, a bit shoulder extending from the shank and a bit head. A 6first portion of the bit shank is in a bore of the chuck. The retainer has a split retainer sidewall, a first end and a second end. The first end has a split retainer collar. The second end has a split retainer ring. The split retainer sidewall is around a portion of the chuck and the bit shoulder. The split retainer collar is around a first surface of the step. The split retainer ring is around a portion of the bit shank between the bit shoulder and the bit head.

Abstract: The present invention relates to a downhole-hammer drill-bit assembly for removable attachment to a substantially tubular casing of a downhole hammer. The drill-bit assembly has a substantially tubular chuck, a drill-bit, and a substantially tubular retainer. The chuck has a step. The drill-bit has a bit shank, a bit shoulder extending from the shank and a bit head. A 6first portion of the bit shank is in a bore of the chuck. The retainer has a split retainer sidewall, a first end and a second end. The first end has a split retainer collar. The second end has a split retainer ring. The split retainer sidewall is around a portion of the chuck and the bit shoulder. The split retainer collar is around a first surface of the step. The split retainer ring is around a portion of the bit shank between the bit shoulder and the bit head.

Abstract: A first hollow block is placed over or next to a second hollow block. Both blocks are filled with soil so that the roots of plants that are planted in the blocks are permitted to grow through openings of the blocks to interconnect the blocks, the roots and the existing ground.