Thanks again to everyone for their input! This thread has gotten far more response than I ever expected and the new material that has appeared requires that a sojourn be planned to check out a few new questions that I am now curious about. I won't go into them now until a couple of us get out and do some "railroad theology"... This is truly an incredible bunch of "forummers"! Thanks!
Chris, Steve answered the question (which you remembered) and the only thing I can add is a memory... During my first summer in Durango (1971) several of us went tubing on the river. This is long before any commercial trips were available. The only bridge crossing the Animas south of Durango was the one lane La Posta Road bridge just south of "Mexican Flats". That bridge is still in place today as an Animas River Trail footbridge. It can be found almost under the present hi-way bridge at that location (you have to look for it). This one lane bridge was retired and a two lane bridge was built around late 1974 / early 1975. In 1980 this two lane bridge was widened into the current four lane one in use today... Back to the tubing... On the first trip down the the river we almost ran into some some pilings that were sticking up out of the water for the old RR bridge crossing to the American Smelter. I knew what they were because of the map. The "west" river side of the bridge had been placed on an outcropping of rocks 15 feet or so above the water at this location. When the new two lane (now four lane) bridge was built, it was placed in the same basic location as the railroad bridge. The pilings were removed from the river at this time. If one goes for a walk along the river trail and crosses the original one lane bridge, this outcropping of rocks can be seen under the new hi-way bridge. I hope I explained this well enough to be understandable... (A lot of wind to set up the small bit of memory!) The smelter location had always been obvious as the slag looked like an outcropping of coal. Many in town, including myself, thought that it was coal not knowing about the second smelter...
The photo shows south of Durango before the first improvement of US 550/160 (now Hi-way 3). The present 550/160 at this location is now on what was La Posta Road going south on the west side of the river. I am guessing that this photo is from the early 40s.
Dave thanks for posting your photos. Outstanding! I went and found them in Dorman's book and I specifically remember the one showing the cars parked on the spur track left going to the smelter. The picture in the book was so small that I had never noticed the cars parked on the City Mine Branch. Don't know if Greg Scholl realizes it but on several of his pictures that he has posted recently from 1968, show this location of the former branch. Also, while perusing the book, I found another picture of the Gold King tipple from the opposite side, another 3/4 shot, that I also remember, but can now place it into context.
MD, thanks also for the kudos. Always the gentleman! We had some great discussions about this kind of thing during breaks at the RR. Hopefully in a month or two I may be able to share some new findings about this interesting spur.
Again, thanks all, this was great! I learned a lot!
El Flop