History 430: Theory and Practice
"From all directions as one approaches Picher, Oklahoma, the mountainous chat piles loom prominently in the distance, impressive testimony to the labor of thousands of miners and mill men who spent their lives extracting and milling lead and zinc ores from the Tri-State Mining District of Oklahoma, Kansas, and Missouri." The mines started to be discovered in the regions of Southeast Kansas and Northeast Oklahoma during and before the turn of the Twentieth Century. More and more people begin to inhabit these regions and with more settlement through the heart of America, shifted to more exploration of the rich resources of lead, and zinc, which were plentiful throughout the region. The increase in the mining industry to the area brought many issues up for the workforce of the mining companies. This led many companies working to benefit themselves and not to think of their employee's benefits or lives. The violent, furious, and persistent unions were very adamant during the 1930s.
Boyd, Jordan L., "The Violent, Furious, and Persistent Unions: Picher, Oklahoma during the 1930s" (2012). Theory and Practice: Hist 430. Paper 10.