Fred, the best detailed that I've seen is in the Gilpin Railroad Era book, page 290. If you don't have this book, you should get it and the matching Sunset published Colorado Central book. And...start searching on Black Hawk or Blackhawk on the DPL digital collections. Good images of the yard area you're modeling in these three sources.
Here's the Gilpin book image:
Not sure why it's rotating the image, I can't get it to orient properly, but it clearly shows the ironwork framing.
That roof on the left is the hay warehouse; this is before the beer warehouse was put in (which happened after the turntable was moved). There are a few images of the turntable when it was moved to the edge of town later. I believe it's the same turntable.
Note also that the yard was bounded by a rough rocky outcrop, visible in other pictures and indicated on the Sanborn maps.
Three DPL images to look at, though none show the TT, are CHS.X4691 (looking down on the turntable location after it was removed, with the hay warehouse on the foreground right edge), X-2146 (right center edge is the hay barn and area where the turntable would be) and X-2032 (bottom right shows station and feed shop in C&S block-lettering days).
Dave Eggleston
Seattle, WA