Mine caps

Federal and State laws dictate certain aspects in the capping process, such as allowances for bats to have access.

Considerations can be made in the design to allow for an entrance to the mine, a steel door for humans, a slot for bats, a hole for airflow.

Expanding foam is quickly replacing concrete for some vertical shafts, typically mines where an entrance for humans is no longer desired.

This has the advantage of allowing mine gas to ventilate, water to drain from horizontal adits, and bats to traverse the grate.

The photo at right is of a 1/4-inch steel-plating cap at the entrance to a horizontal shaft at the Petherick Mine, located in Keweenaw County, Michigan.