Situations Requiring Expert Advice and Custom Designs
Closing mines by use of steel gates, cupolas, backfilling, and other means can often be accomplished using standardized designs. Standardized designs are intended for use at features presenting no unusual conditions. It is common for about 10–20% of sites to exhibit unusual attributes which require expert, custom designed closures. The following is a watch list of situations triggering the need for custom designs or consultation. Contact Bat Conservation International for additional information.
- Sites in which large numbers of bats are roosting.
- Sites located in snow zones where snow creep or loading of cupolas or other structures can cause damage.
- Sites where acidic mine drainage or corrosive environments are present.
- Sites with unusual wildlife species requiring protection.
- Sites with historic features or structures requiring protection.
- Sites where closures will be in an area of high visitor use, or when the closures will attract public attention.
- Sites with sloughing or unstable walls requiring special design considerations for stabilization.
- Sites which include stopes open to the surface.
- Sites involving long or complex mines, especially mines with multiple surface openings, and/or vertical relief that generates airflow. (A closure plan may be needed with the objective of maintaining the internal microclimate.)
- Sites that need complex structures to close irregularly shaped or large openings, especially when structural stability is an issue.
- Sites requiring specialized door designs. (Access for claim holders, underground tours, interpretation, etc.).
- Sites requiring structural support of shafts or tunnels.
- Sites with low oxygen or toxic air conditions present.
- Sites that are not mines.