RECO was contracted to supply over 1000m of precast TechSpan® arch units to house reclaim tunnels below coal stockpiles.  Variable loads, corresponding to stockpile heights up to 25m were accounted for.  The coal was housed in cast insitu chambers containing electronically operated valves to regulate the release of coal onto the conveyor below.  Allowance for suspending the conveyor from the arch itself was also required.  An impervious membrane was installed atop each wall to seal the structure and direct all moisture away from the Reinforced Earth block and concrete headwalls were used at the tunnel entrance.