elminero
You may used the photos. I'm not sure what the resolution is. I have a few others also. Send me a PM for details.
There are two references, which you might already have, that might be of interest to your search. One is "A Brief History of Puerto Penasco" by Guillero Munro Palacio, 2007, self published. A magazine really. There are photos of the old mine and some photos of Gillespie, none of a railroad. One old photo shows rails coming out of the shaft for dog carts I would guess. Another book, which I have not yet seen, is 'Gillespie's Gold" by Earl Mac Pherson, 1973 also appears to have been self published. Love to have a copy of that.
The old photos in the Penasco book are owned by Palacio. He may have more.
With reference to Myrick's description of the railroad, I'm quite sure it is not 16 miles from the mine to the sea. I guess one could check on Google Maps. Also, I don't see who they would be marketing it too as it could have only served one small mine, unless it was a scam to get investors. There was an attempt to build a railroad from Ajo to bring copper ore to the sea for shipping which never took off.
Stuart
Yes, was and still is a gold mine. May have been worked by the early Spanish as other mines nearby have been. Owned by a British company around the turn of the century, obtained by Gillespie around 1930 allegedly by paying off a judge! By 1970 Mac Pherson reported that the mine had not been worked in 20 years. Gillespie apparently built the stone hacienda at La PInta which I know you are familiar with. He also put in a well about half way to the mine where he planted an orchard. The water cistern is still there. He is quite the legend, apparently he was well know around Sonoyta. The road past the mine connects to the highway just outside Sonoyta and can be traversed by 4WD.
Sea
There is a lot of rubble all around the area but none that would have obviously fallen off the ore carts. I worked the arroyos with a metal detector down drainage from the mine a bit, intending to work up to the mine. My logic was that natural erosion over eons may have carried nugget bearing rock down the drainage. Last visit I was stopped by the military who told me they had a shooting range in the area and that the mine was being worked and to stay out. That was about 2 years ago. No, I found no gold, just an old piece of barbed wire but I'd still follow up if I could. BTW, I have been told that the owners are increasingly protective of the mine. You can see some buildings off to the NE and I was concerned that anyone there could view vehicles coming into the mine.
There is an interesting old 50's Studebacker President shell along the road with racing stickers on it !! My son swiped the emergency brake handle out of it!
Here's my fav shot of the area. It's my screensaver.