You are on the "right track" as photo's with the Roundhouse still standing, do show large piles alongside the Wye leg. These are in Gunnison by RH Dorman on pg33/34, and pg117/123 also visible between the Depot and W.T. pg124 of Trails/Columbine 1990.
Being that Sargent, like Cimmaron are Helper stations as opposed to Terminals like Gunnison, did they rate full facilities? Branchlines such as Ouray just had a pile beside the track. Just dumped between the rails and then piled up to be later removed. Note that the Sandhouse supply track at Sargent extends far enough to spot cars for ash removal.
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