Homestake Mine typically worked very large stopes, sometimes using a variant of what is now called sub-level caving. I visited it in the late 1970s and if was using a backfilling process, I don't know about it.
further research produces the information that early mining methods were shrinkage stoping, using huge quantities of timber; the mine was at one stage, flooded to put out a fire which burned for 66 days.
sorting and hand-stacking of deads wouldn't be consistent with the bulk-extraction methods used at the time.
It's probably a 'safe' walkway or tramming way protected from scats falling from above. The 'shed' is nothing like strong enough for any sort of serious ground support, looking at it. The mine also apppears to have used horses and mules underground, hence the size of the walkway?
it seems that in the late 1970s a method called 'vertical crater retreat' was developed, which appears to be a variant of sub-level caving. There was also apparently a switch to mechanised backfilling methods in the early 80s. This all tends to suggest that mining methods varied somewhat on different levels or in different areas, not that that would be anything unusual
''the stopes soared beyond the range of our caplamps' - David Bick...... How times change .... oh, I don't know, I've still got a lamp like that.