1911 - 1941: The Union Pacific Coal Company's No. 4 mine in Hanna
The Hanna No. 4 mine started mine development in 1911 and opened coal production in 1912. The mine produced only 29,583 tons of coal in its first year. The mine closed production in 1941 when the mining operations were moved out of Hanna to the new 4A mine facility north of town. The mine operated in Hanna for 30 years and produced 10,226,125 tons of coal with a peak work force of 331workers. The Hanna Basin mines (Hanna, Elmo, Sampo, Carbon, Dana, and Wagon mines) experienced a total of 372 miner deaths. The No. 4 mine in Hanna was responsible for 24 of the 372 deaths.