Coal Bin loading question

I am scratch building a 8' by 8' C&S type depot coaling bin from photgraphs and a C&S bill of materials from a Maxwell plan sheet. The drawing shows "loose boards" for the doorway, but has vertical lines in the doorway, which makes no sense. I'm assuming they are of the angled "slat" variety that can be also observed on D&RGW bins. The angled slats filled up approximately the botton 3/4 of the door opening.

Which brings me to my question:
Assuming that this bin sat about a car's-width from the nearest track, how did they get the coal from a gondola (or coal car in C&S parlance) into that small opening approximately 5 feet off the ground and 36" wide?

Maybe a chute of some kind that they could hand-shovel the coal into so it slid down into the bin?

Has anyone seen any pictures of this operation? Thanks!

Norm in Littleton, CO
- on the C&S Silica Branch

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RGS 20, 0404 & B-21, URy 50, D&RGW 491, B-8, 0578, 280, C&S 1113 & 1009, UTLX 55172
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C&S 4319