Dave,
Look at page 333 in Book XI. This aerial photo was messed with at Sundance to enhance it in contrast as it was clearer in the original. Anyone can go to the aerial photo in USATerriServer or study other aerials. On page 333 look at the end of the tail of the yard and can you see a white line in the bushes that seem to curve to the right and then curve less to the left to the left of #15, the susposed site of the first mine?
But later in the letter to enlarge the tail, the letter said that their crew built a grade but no track was there per the map attached to the letter. Did they build a grade over what was a track initially in 1906 but quickly cut back to the later working mine?
Sure would be nice to discover this to be a really short lived piece on ng out that way.
Most likely it was just the driveway used after 1900 to access that first mine and did not receive track. But the first report to the ICC Statistics showed a mile longer railroad that ever found. This is the fun of research, the answers never come.