Pioneer Tailings is a local government-owned earth dam located in St. Louis, Minnesota, with a primary purpose of containing tailings. Completed in 1961, this dam stands at 25 feet in height and spans 2000 feet in length, with a storage capacity of 590 acre-feet. Situated near Lonsdorf Creek, this structure has a low hazard potential and has not been rated for condition assessment.

The dam is regulated by the Minnesota Department of Natural Resources, with state permitting, inspection, and enforcement in place. Despite being in operation for several decades, the last inspection occurred in August 2016, with an inspection frequency of 8 years. While the dam has not been assessed for condition, it is important to note that emergency action plans, risk assessments, and inundation maps have not been prepared or updated.

For water resource and climate enthusiasts, Pioneer Tailings presents an intriguing case study in dam management and regulatory oversight. With its historical significance dating back to the 1960s, this structure serves as a reminder of the importance of regular inspections, maintenance, and emergency preparedness in ensuring the safety and integrity of water infrastructure in Minnesota.