the first backfill plant at the Buick Mine went into operation in 1993. The plant is composed of an 8—m3 Denver mixer fed by two Conveyor belts, one of which feeds cement and fly ash from two 63-tonne bins and the other which feeds cycloned railings from a storage hopper [Figure 5.21. Cement and fly ash are delivered to the underground bins from surface via a 20-cm-in-diameter,