1942-1954: The Union Pacific Coal Company's Hanna No. 4A Mine
The Hanna No. 4A underground mine was developed in 1941 and started production of coal in 1942. The mine was abandoned in 1954 when all the Union Pacific Coal Company mines in Hanna closed. It was the last mine opened by the Union Pacific Coal Company in Hanna. The mine produced coal for a total of 13 years. Over that time it produced 9,133,659 tons of coal with an average yearly work force of 320 workers. In the years 1943, 1944 and 1945, the mine produced over one million tons each year. The Hanna Basin mines (Hanna, Elmo, Carbon, Sampo and Dana) experienced a total of 372 miner deaths. The No. 4A mine in Hanna was responsible for 7 of the 372 deaths.