File:Helper UT Retired Power Plant (-0098).jpg
The power plant in the lower middle portion of the picture is referred to both as “Carbon Power Plant” and “Castle Gate Power Plant”. It was coal-fired and considered to be a comparatively small power plant. The plant units opened in 1954 and 1957, the plant was shut down in April, 2015. Per the article linked below, the plant was retired comparatively early because its location in the canyon left too little room for installation of filtration equipment needed to reduce mercury emissions.
www.sltrib.com/sltrib/news/56919729-78/coal-power-carbon-...