In combination a loader unit and haul unit for use in a block caving mining operation. Each of the loader unit and the haul unit comprise a removable bucket, which can be used for loading ore. In use the bucket carrying a load of ore can be transferred from the loader unit to the haul unit so that the haul unit can transport the ore from a loading site to a crusher. The loader unit and haul unit have a respective longitudinal axis extending from the fore end to the aft thereof, and the bucket is elongate with a longitudinal axis. In use when the bucket is mounted to the loader unit the longitudinal axis of the bucket is disposed orthogonally to the longitudinal axis of the loader unit. When the bucket is transferred to the haul unit, the bucket is placed upright on the haul unit with the longitudinal axis of the bucket parallel to the longitudinal axis of the haul unit.