Effect of gate installation on continued use by bats of four abandoned mine workings in western Montana
By: submitted by Paul Hendricks.
Contributors: Montana Natural Heritage Program.; Montana. Mine Waste Cleanup Bureau.
Publisher: Montana Natural Heritage Program
Published: 1999
Place of publication: Helena, Mont
Language: eng
Number of pages: 13
Subjects: Bats -- Habitat -- Montana -- Lake County.; Bats -- Habitat -- Montana -- Jefferson County.; Abandoned mined lands reclamation -- Environmental aspects -- Montana -- Lake County.; Abandoned mined lands reclamation -- Environmental aspects -- Montana -- Jefferson County.; Abandoned mines -- Montana -- Lake County.; Abandoned mines -- Montana -- Jefferson County.; Bat-compatible mine gates -- Montana -- Lake County.; Bat-compatible mine gates -- Montana -- Jefferson County.; Anabat bat detection systems.; Little brown bat -- Montana -- Lake County.; Little brown bat -- Montana -- Jefferson County.; Plecotus townsendii -- Montana -- Lake County.; Plecotus townsendii -- Montana -- Jefferson County.; Bats -- Hibernacula.; Culvert gate system.; Lewis and Clark Caverns State Park (Mont.)
Description: In 1996 the Mine Waste Cleanup Bureau of the Montana Department of Environmental Quality installed culvert gate systems in the portals of four abandoned mine adits in western Montana.  Two gates were installed at the McDonald ("Ravalli") Mine adits in Lake County, and two more were placed in portals at the Gypsum Mine workings of Lewis and Clark Caverns State Park in Jefferson County.  Inspection of these mine adits prior to gate installation revealed that each was used at some time during the year by bats, particularly Townsend's Big-eared Bat (Corynorhinus townsendii), a U.S. Fish and Wildlife Service species of special concern (Harvey et al. 1999).  Gates were installed to allow for continued use of each mine working by bats while prohibiting accidental livestock entry and unauthorized access by humans.  Gates were built with 13 mm rebar attached at an angle iron gate frame, using recommended vertical spacing at least 5.75 inches and horizontal spacing at least 24 inches (Tuttle and Taylor 1994, Dalton and Dalton 1995).  The gate itself was attached to a corrugated metal pipe that was inserted into the mine portal, surrounding the pipe with fill to assure that entry into the mine was through the pipe and gate; the gate was secured with a protected padlock.  Although the gate design was supposed to be bat-friendly, no follow-up study has been conducted at any of the sties to determine if bats were still using the sites after gates were in place.  The objectives of the work described in this report were two-fold.  First, determine the effectiveness of the gate design in its primary function of allowing continued access by bats to the mine workings.  Second, gather mine environment data (temperature, relative humidity) continuously over a several month period to aid in characterization of the mine environments where bats occurred.