The Mechanics of Mine Closure in Joshua Tree National Park

A legacy of the fevered search for gold in the West, there are over 300 abandoned mines in Joshua Tree National Park, so many that they have become an indelible part of the park’s landscape. Mine shafts have come to serve as wildlife habitats, especially for bats, and they provide a good source for cultural resources studies. But they also pose a risk to the unwary. It is for this reason that GBI has partnered with the National Park Service and Joshua Tree to seal off sites that have been deemed unsafe. As a Physical Science Technician, GBI Research Associate Allison Dunkel helped to assess and close some of these openings. She also documented the experience photographically, and provided the below time-lapse video showing the lowering of a culvert into the shaft at Independence Mine.

Allison explains the procedure: “We needed to remove a head-frame, install the culvert, seal it in place using polyurethane foam (PUF), then reinstalled the head-frame. The goal was to leave the site looking like we were never there, but also keeping our visitors safe!” Indeed, her before-and-after pictures show very little superficial difference, but below the surface are structures that will help prevent future accidents.

Before and After pictures of the Independence Mine shaft closure.

In addition to contributing to public well-being, Allison found the experience personally fulfilling, as well. As she explains, “I got to camp out in the back country with a couple other amazing females for a week. It was an amazing opportunity to learn about the compliance work and planning that goes into a mine closure within a National Park. This was a very challenging, yet extremely rewarding project!”

2 Comments

  • Ronna says:

    Are there any concerns that bats will be trapped in these mines or can they fly out the culvert?

    • Marc Oxoby says:

      Thanks for your question, Ronna. We reached out to Allison Dunkel and here’s what she had to say: “We work with other branches in the park to determine the best type of closure for each mine. There are wildlife monitors to look for bats, tortoises, and other animals. At this site, we did not find any bats actively nesting before the work was done, but there were remnants of an old bat nest. The culvert that was used will allow bats to enter and exit the shaft opening if they try to come back to the area. We try our hardest to make sure that everything is safe; not just for humans, but for our animals and plants too!!”

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