This site is part of the Southeast Missouri Lead Mining District and within what is known as the "Old Lead Belt." According to the Incidents of Mines, Occurrences and Prospects (IMOP) database created by the state of Missouri, there was only limited mining within the current boundaries of Lake Timberline. However, the Mississippi River and Bonne Terre Railway (MR&BTR) runs through the development. This railway (now abandoned) is comprised of mine waste (chat, tailings, smelter slag, etc.) based on visual observations and sample results. Three lakes within the development are adjacent to and receive storm-water runoff from the MR&BTR. In addition, based on documented conversations with some Lake Timberline residents, it appears lead-contaminated soil and gravel have been brought in from the surrounding areas. The soil was used as fill and the gravel was used for driveways throughout the community.
