Abstract: A machine for mixing a resinous binder compound with aggregates on a continuous flow basis to produce a building material or the like, without the use of cement or water. Aggregate is fed into a first mixing chamber where a metered amount of resin binder composition is added thereto. The mixture is then passed into a first rotating mixing tube having a rotating mixing screw conveyor therein with triangular teeth between the convolutions of the screw. The outer tube rotates contra to the direction of the inner screw which produces a thorough mixing action, coating each particle of the aggregate with the resin binder composition. This mixture is then fed into a second mixing chamber where a metered amount of a second resin binder composition is mixed with the aggregate. A second mixing tube, also having a rotating mixing screw conveyor and triangular teeth, then thoroughly mixes the blend. The resultant aggregate product is then conveyed to a discharge spout.