Abstract: The Tri-State District – located in Missouri, Kansas and Oklahoma – was a world-class zinc-lead district that produced ore from the mid-1800s to 1970. The deposits are hosted primarily in carbonate rocks, with sphalerite and galena the major ore minerals. The long history of the district means it spanned many changes in mining technology. Mining varied from early “camps” with hundreds of small shafts to more modern mines and methods. New potential in the district may occur for recovery of critical minerals from remaining mine waste.

Biography: Cheryl Seeger has been a geologist with the Missouri Geological Survey for more than 30 years, working primarily with ore deposits. Her degrees are from the University of Missouri – Rolla (now the Missouri University of Science and Technology and earlier the Missouri School of Mines). She is a native Missourian who bounced around a bit after her Bachelor’s degree, but came back to and still loves the Missouri Ozarks.