For over a century, Sunnyside was the leader in coal production in Carbon County. The history of coal mining in Sunnyside began shortly after Jefferson Tidwell and his three sons discovered coal in Whitmore Canyon in 1896. By 1898, the Pleasant Valley Coal Company had acquired the rights to the coal from Tidwell. On July 4 of that year, the Sunnyside railhead was abandoned by the D&RGW, and the coal camp located in Whitmore Canyon was named Sunnyside. By 1901, the D&RGW and its subsidiary, Utah Fuel Coal Company, acquired the operation.