This 1/2-hour breathing apparatus is on display at the World Museum of Mining, and was invented by Butte’s Dan Crowley. It was invented for use in the Butte underground mines after the Granite Mountain-Speculator Mine incident which killed many of miners.
The equipment is in a glass case so I used my polarizing filter to cut the glare as well as the assistance of WMOM employee Logan to help me hold my coat up behind my camera to avoid glare from windows.
