system as the concrete charging hopper but could by physically separate if desired that secondary charging station 26 is also preferably provided with positive discharge means again shown as a rotating roller 52 with suitable blading 53 and is further associated with a counter rotating roller 54 that will skid on the surface of the concrete to assure even distribution of sand thereon a doctor blade 55 is shown associated with the spreading roller 54 thereafter the finish or facing layer is consolidated with the concrete substrate by a series of rollers 56 bearing thereon at station 28 in a carriage 57 that is reciprocated to and fro in the direction of travel of the conveyor 10 downward pressure is required of the carriage 57 and rollers 56 for consolidation purposes but need not be as great as was required hitherto the rollers 56 will bear on the concrete via an elastomeric compression sheet which can apply a particular pattern if same if required to be imposed on the finished or faced surface the next stage is the drilling stage 30 where holes are made in the slabs or tiles at positions appropriate to their size and type a plurality of drills 60 are shown one for each possible position of several sizes and types of tile or slab preferably corresponding to all normal production options for the machine the drills 60 are each indicated as spring biassed see 61 in fig4 b for cushioned engagement with the plates 37 the drills 60 are carried on drill frames 62 themselves movable down pillars 63 by actuator 64 against spring bias 65 except when operated by actuators 64 the drill frames.