Another mine adventure with Ryan, this time to help map an active mineral mine in southwest Arizona. Kidsitting until late Friday made for an unpleasantly late drive down past the Salton Sea to the southern border. Plan A was to soak and then car camp near Holtville Hot Springs but I was discouraged by the large number of cars indicating the small hot pool would be packed and then I found out that the nearby BLM campground was exclusively set up for long term visitation with no mechanism for single night stays. Annoyed I drove further east to a place I knew I could camp off of Ogilby Road, crashing out around midnight. I underestimated the nighttime temperatures and between my 40degree sleeping bag and my negative insulating car air mattress I had a cold and not too restful night.
I awoke early and carried on for the final 2 hour drive to the Gila Bend area. After a good amount of faffing around, we finally got ready to start the survey. Fairly quickly we ran into challenges with the plethora of metallic objects generating magnetometer errors, but eventually I got comfortable working around this by doing backshots when needed. We started with the Jobes Decline, a steep ladder entrance that led into a 45 degree slope following the main mineralized fault. Several of the larger rooms were in this area, as well as several side drifts. I was mostly on task with mapping, but whenever I had a spare second I was impressed at the rare and unusual lead mineralization (galena, wulfenite, vanadinite, mimetite, etc.) as well as the very complex layered barite breccia in the fault's hanging wall. It turned out that the Jobes Decline was disconnected by the rest of the mine by only a few feet of fill.
With Jobes done, we began the annoying task of surveying in bright daylight over to the main decline about 150 ft away. My survey target and red glasses made it possible to barely keep track of the laser spot with care. There was more annoying metal to contend with at the main entrance but eventually we got in and descended the welded ladders deep into the mine. We worked hard the rest of the day, mapping more than half of the mine until after 7pm. In the process we mapped five major loops, each time I was impressed with our minimal loop closure offsets. For one loop I had to do a flat-out belly crawl, then awkwardly wait while Ryan looped around to the pleasant passage on the other side. We ended the day's survey by knocking out the most challenging part: surveying from a mid-shaft adit to the base of the vertical shaft just above the water table, and then trying hard to connect up to the surface. Initially I went out to try to find the keys and try to survey down the shaft from the surface, but this was not working and so I went back in to join Ryan at the deepest point in the mine. Here on a makeshift platform cantilevered over the water I struggled to steady my hands enough to complete three consecutive 170ft length shots up the shaft. This took quite some time and I was getting pretty discouraged by we managed to barely spot a bright steel spot reflective enough that I could get a clean shot off of. Success! The crux of the survey was done. Our last task of the day was to do the surface survey (in the dark!) from Jobes over to the vertical. We were dirty and coated with a thick greasy rusty grime. Done for the day, we finally deserved a warm alkalic shower, clean clothes, and food, drink, and socializing. Once again I struggled with the temperatures and slept poorly.
The following day we got a somewhat earlier start and had about 4 more hours to wrap up the survey. The second and final crux of the survey, the part we left for last, was to survey the adit that had been taken over by at least a hundred bats and reeked of ammonia. With that completed (2483 ft total survey in 125 stations), we exited to have a late lunch on the surface and drop off the survey gear. After about all the sun I could handle we reentered the mine, this time with the goal of poking around and collecting some mineral specimens. It was only really now that I could appreciate the weird mineralization. After several hours of collecting I ended up with a box of about a dozen rare minerals, and a couple 5 gallon buckets worth of superbly bright blue yard rocks of silicicated copper minerals.
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| Wulfenite (and below) |
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| Mimetite |
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| Vanadinite |
Ryan and I both had lengthy drives so after a rejuvenating shower I packed up and began the drive working towards a midnight arrival back home. Thanks to Ryan and Ed for a neat weekend away. A fascinating mine! After many hours of drafting I am quite happy with how the map of the mine turned out.
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