An explosive booster for initiating, and thus causing detonation of, a bulk explosive,
includes a hollow body comprising a base member and a sidewall projecting from the
base member. The body defines an interior space between the base member and the
sidewall for containing a detonable booster formulation in use. A hollow elongate initiator
locating formation projects longitudinally into the interior space at least from the base
member and defines an initiator channel that is open through the base member, for
locating an explosive initiator in initiating proximity relative to a detonable booster
formulation contained in the interior space in use. The initiator channel extends
longitudinally along a central longitudinal axis thereof that is radially spaced from, and
parallel to, a central longitudinal axis along which the interior space longitudinally extends.