Non-coal Lead/Zinc Shaft Closures
Each year, the department’s Land Reclamation Program receives federal Abandoned Mine Land funds to reclaim abandoned coal mines. The funds come from a per ton tax on coal production collected by the federal government and distributed to eligible states with abandoned coal mine problems using a funding formula. A state may request a portion of these funds be used for closing extremely dangerous, non-coal mine shafts that present an imminent falling hazard likely to result in death. Since 2001, Missouri has used this flexibility and has successfully closed more than 90 dangerous non-coal shafts at a cost of more than $800,000. Most, if not all of these non-coal shafts were from historic lead mining. On average, approximately $100,000 of the funds received each year has been used for this effort. Shaft closure cost averages approximately $9,000 per shaft, but may vary widely due to specific site conditions.
An example of a dangerous shaft opening in a residential area is the 2012 Webb City Elk’s Lodge Shaft Reclamation Project in Jasper County. It was discovered the sudden opening of a vertical shaft was associated with an abandoned underground lead/zinc mining operation. The shaft opening was considerably large (30 feet by 30 feet) and the edges of the opening were highly unstable as there was a constant sloughing off of material. Review of old mine maps of the area recorded the depth of this shaft to be well over 200 feet to the bottom of the old mine workings, which dated from the 1920s. The dangerous shaft was made safe by construction of a steel reinforced concrete plug over the shaft opening. The sealed opening was then backfilled to the surface, shaped to drain and revegetated with grass. Due to the immense size of the mine shaft, the total final cost of $19,656.74 was much greater than sealing the average shaft opening.