The dangers of open mines are increasingly recognized, and authorities and landowners are capping shafts and blocking entrances. Some of these mines, especially in Europe, have been used by bats for up to 2,000 years. As bats have been disturbed or o
therwise excluded from their natural roosts in caves, they have become increasingly dependent on less disturbed mines. Some of the world's largest hibernating populations of bats now live in mines that are critical to their survival.
The problem of mine closure was highlighted in March, 1983 when Dr. Robert Stebbings heard about a large-scale shaft capping operation in West Cornwall, England. Seventy full-time employees were solidly capping up to 2,800 mineshafts without consideri
ng bats. A survey of remaining shafts revealed evidence that several had recently been used by at least one colony of the endangered Greater Horseshoe Bat (Rhinolophus ferrumequinum). Measurement of guano piles and eyewitness reports by locals s
uggested a colony in excess of 1,000 bats, making it the largest colony known in Britain. Hopefully, this colony is not already entombed in a capped mine. Surveys of the remaining uncapped mines in West Cornwall are now in progress.
Publicity given to capping in the U.K. has resulted in many inquiries about the methods used. These have come from countries ranging from Canada to Argentina and Australia. Such projects are also receiving increased attention in the United States.
In Wisconsin up to 95% of all hibernating bats live in abandoned mines, and some of these mine populations are among the largest known in North America. Yet recent legislation nearly forced closure of all Wisconsin mines without consideration of the co
nsequences for bats. Most originally occupied caves in the state are now commercialized or too heavily disturbed to permit further use by bats.
In Canada, the Renfrew Mine shelters one of that country's largest populations of hibernating bats. However, its bats were nearly lost through a recent mine closing. As a result of Dr. Brock Fenton's involvement the mine is now being protected by a c
ombination of gates and a fence at a cost of $7,000. The original plan would have eliminated the bat population and would have cost $32,000.
It is important to assure that all mine capping plans consider bats in early planning stages. As in the recent Canadian example, the consequences may prove beneficial to all concerned.