A dual circulation fluid hammer drilling system for drilling a hole in the ground comprising: a drill string having an up hole end and an opposite down hole end, and a hammer drill having, an outer tube, a drive sub and a drill bit with a bit face, the drive sub connecting the drill bit to the outer tube and the outer tube connecting the hammer drill to the downhole end of the drill string; characterized in that the drill string comprises one or more dual wall pipes, connected end to end, each dual wall pipe having an outer wall and an inner wall, the outer wall surrounding the inner wall, wherein an annular space is formed by and between the inner wall and the outer wall the annular space constituting an annular flow path for a first fluid, and the inner wall forming a central flow path for a second fluid, the annular flow path and the central flow path configured to separately convey the first fluid and the second fluid down a hole, and in that the hammer drill is configured to enable a flow of fluid between an outer surface of the hammer bit and an inner surface of the drive sub and to leave the hammer from a downhole end of the drive sub; and; the annular flow path delivers the first fluid to the hammer drill wherein the first fluid provides power to drive the hammer drill and flows between the outer surface of the hammer bit and the inner surface of the drive sub, leaving the hammer from the downhole end of the drive sub; and the central flow path delivers the second fluid to the hammer drill and directs the second fluid to flow through the drill bit and across the bit face when the bit face is in contact with a toe of a hole bring drilled; and wherein the first and second fluids (16,18) flow back up the hole being drilled through a single annulus formed between an inside surface of the hole and an outside surface of the drill string. a drill string having an up hole end and an opposite down hole end, and a hammer drill having, an outer tube, a drive sub and a drill bit with a bit face, the drive sub connecting the drill bit to the outer tube and the outer tube connecting the hammer drill to the downhole end of the drill string; characterized in that the drill string comprises one or more dual wall pipes, connected end to end, each dual wall pipe having an outer wall and an inner wall, the outer wall surrounding the inner wall, wherein an annular space is formed by and between the inner wall and the outer wall the annular space constituting an annular flow path for a first fluid, and the inner wall forming a central flow path for a second fluid, the annular flow path and the central flow path configured to separately convey the first fluid and the second fluid down a hole, and in that the hammer drill is configured to enable a flow of fluid between an outer surface of the hammer bit and an inner surface of the drive sub and to leave the hammer from a downhole end of the drive sub; and; the annular flow path delivers the first fluid to the hammer drill wherein the first fluid provides power to drive the hammer drill and flows between the outer surface of the hammer bit and the inner surface of the drive sub, leaving the hammer from the downhole end of the drive sub; and the central flow path delivers the second fluid to the hammer drill and directs the second fluid to flow through the drill bit and across the bit face when the bit face is in contact with a toe of a hole bring drilled; and wherein the first and second fluids (16,18) flow back up the hole being drilled through a single annulus formed between an inside surface of the hole and an outside surface of the drill string.