A case study of acoustics and vibration of mine fans

Some officials and residents of Hueytown, Alabama, have speculated that the `Hueytown Hum´ is produced by a mine fan which is owned and operated by Jim Walter Resources, Inc. (JWR) and that the most likely transmission path is through the air, although some speculate the ground may also be a factor. As a result, both air and ground transmission paths were investigated. Sound recordings were taken and analyzed, and fan-site and geologic conditions were reviewed for ground transmission potential. Fan noise in the Hueytown area can be detected; however, the amplitude of this noise is too low to measure with a standard handheld sound-level instrument because of interference from the ambient background noise. The detected fan noise does not have the characteristics of sound that some of the residents complained about, such as the hum being a very steady humming sound that does not change in tone or pitch. In addition, it is highly unlikely that ground vibrations from any of the JWR fans could be detected in the Hueytown area