1911 - 1925: Union Pacific Coal Company No. 3.5 Mine at Hanna, Wyoming
The Hanna No. 3.5 underground mine was opened for development October 1, 1911 and started coal production in 1912. The mine opened with a 125 H.P. Allis and Chalmer electric hoist on the slope with a 1.25" rope. Mules were used for haulage from the entries to the slope. The track gauge was 42" with 3 ton pit cars. The No. 3.5 and No. 3 mines shared the same coal dump. The mine produced coal for 14 years and over that time produced a total of 726,901 tons of coal. The Union Pacific Coal Company produced 491,781 tons of coal from 1912 to 1920. The mine was leased to John W. Hay of Rock Springs in 1920 to complete the cleanup work. The name of the new company was the John W. Hay Coal Company and the leased mine started operations on Oct. 1, 1920. The John Hay Coal Company was also known as the Hanna Coal Company. The mine operated the same vein of coal as the old No. 3 and was driven as a panel slope mine. The primary work in the mine was driving the rooms and the extraction of the pillars. The average daily output was about 500 tons per day. The John Hay Mine Superintendent was R. B. Ober and the Mine Foreman was William Hughes. The mine ended coal production in 1925. The Hanna Coal Company produced 262,161 tons of coal from 1920 to 1925. The Hanna Basin mines (Hanna, Elmo, Carbon, Sampo and Dana) experienced a total of 371 miner deaths. The No. 3.5 mine in Hanna was responsible for 2 of the 371 deaths.