The Swedish Defense Recruitment Agency – Ranger test
Sound six: Ranger test. Only a few recruits takes this special test which determines if you are able to become a Ranger…

When mining coal or other minerals took the miners ever deeper into the ground, it became necessary to ventilate the shaft, in other words to supply sufficient fresh air in order to protect the coal miners from suffocation. In doing so, diverse methods were applied, which depended on the type and the depth of the mine.
In the visitors’ coal mine exhibit of the LWL-Industrial Museum Nightingale colliery, air pressure is directed into the shaft through a pipeline and enters the mining gallery through a duct whose diameter increases along its length. This type of pipe is called a diffuser. With it, the amount of air exhausting out of a duct is increased. At the same time, the amount of noise made by the exhausting air is reduced. All one can hear is a steady, low whisper of the airstream.
Sound recordist: Konrad Gutkowski / Jonathan Nicolai / Anna Pietzuch
Video recordist: Konrad Gutkowski / Jonathan Nicolai / Anna Pietzuch
Photographer: Konrad Gutkowski / Jonathan Nicolai / Anna Pietzuch
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