Sequoia & Kings Canyon National Parks (CA)
Abandoned Historic Explosives Found In Crystal Cave

Park employees working in Crystal Cave late last Thursday afternoon found what appeared to be live explosives left over from the 1930s. All visitors and employees were evacuated from the area. Park officials also contacted the chief regional blaster, who is certified by the NPS in the handling of abandoned explosives and who also happens to work in the park. On Friday, the chief blaster and a cave specialist assessed the situation and found three drilled holes which may contain unexploded charges. The CCC opened up trails in the cave in the 1930s using small explosive charges to widen passages and increase head space where they deemed it appropriate. The discovery of the abandoned explosives was made while the cave specialist was planning a new lighting system for the cave. Efforts will begin this week to remotely remove the wires and any attached explosives. There’s a distinct possibility, however, that the explosives used to develop the cave included nitroglycerin, which becomes unstable over time. The safest course of action therefore may entail detonation. In preparation for that possibility, park staff will install temporary blasting mats and blankets to protect cave formations and features. The area remains closed.

OK.

I always thought the most hazardous thing about the cave was the poison oak growing along the paved trail from/to the visitors center.

Wow that's crazy. I did the Wild Cave explorer's tour last year, which was awesome and I think lasted about 5 hours-- we spent a lot of time crawling on our bellies through tight spaces.

Whew! Glad they didn't go off during a tour!

A few years ago I did the basic Crystal Cave tour and at one point the tour guide shut off all the lights and said it is impossible to see in the dark. However, I was wearing a dark flannel jacket and a white T-shirt underneath, and while the lights were out I clearly could see my tshirt, and opened and closed the jacket a few times because I couldn't believe my eyes. Turns out humans do have a very slight residual ability to see in the infrared. I wouldn't have known that without the cave tour!

New selling point for the cave tour: IT'S A BLAST!

Vince: you are right, the human eye does respond into the near infrared, but the photon flux needed for perception is many orders of magnitude greater than that emitted by room temperature (or human temperature) objects. What you were actually seeing was phosphorescence from a chemical introduced onto the shirt either during the manufacturing process or laundering.



Post Edited (05-21-08 07:15)

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THE YOSEMITE POST
Voice of the Rocky Marmot Empire

szalkowski wrote:

> New selling point for the cave tour: IT'S A BLAST!
>
> Vince: you are right, the human eye does respond into the near
> infrared, but the photon flux needed for perception is many
> orders of magnitude greater than that emitted by room
> temperature (or human temperature) objects. What you were
> actually seeing was phosphorescence from a chemical introduced
> onto the shirt either during the manufacturing process or
> laundering.

Probably optical brighteners. They supposedly take in UV and slowly emit visible light back. It's most pronounced when your in a dark room lit with "black light". It'll give an eerie purplish glow. Tide uses lots of optical brighteners, as do many other laundry detergents.

The DoD has specific laundering instructions which don't recommend optical brighteners. Optical brighteners will supposedly make one more visible under infrared night vision as well as other detection methods.

Hey you learn something every day hopefully. I'm just glad I wasn't imagining it.

And much more glad I wasn't pinned in a beautiful cave by dynamite...can't navigate by the light of a t-shirt

Late on the afternoon on May 15th, park employees working in Crystal Cave found what appeared to be live explosives. After the discovery was made, all visitors and employees were evacuated from the area and park officials contacted the chief regional blaster, who is certified in handling abandoned explosives. On May 16th, the chief blaster and the park’s cave specialist assessed the situation and found three drilled holes that potentially contained unexploded charges dating back to the late 1930’s. They worked with park managers and staff to formulate a plan to remove any explosives with little to no damage to the natural formations in the cave. On Tuesday, May 20th, the chief blaster removed the wires from the three holes in an operation that lasted until 9 p.m. He then set off a total of seven small charges in an effort to cause the historic explosives to ignite, but none did so. The materials were determined to be inert and were manually removed from the holes. Crystal Cave reopened to the public at noon on Wednesday.

will this be part of the regular tour or do you have to pay extra

and at the park museum you can buy t-shirts saying I Survived Crystal Cave