Covia | Wisconsin Sand Mines Home to Thriving Bat Populations

En Español

Covia Holding Corp.’s Maiden Rock mining facility in Maiden Rock, Wisconsin has operated as an underground mine for industrial sand since 1999, removing and processing between 500,000 to 700,000 tons of sandstone from the mine each year. Over time, these mining operations created large, abandoned tunnels, which were soon occupied by tens of thousands of hibernating bats like big brown bats, little brown bats, northern long-eared bats, and tri-colored bats. This incredible phenomenon has created one of the largest shelters for hibernating bats in the Midwest.

Since 2005, Maiden Rock’s team has worked with the Wisconsin Department of Natural Resources to enhance bat habitat across 650 acres, protecting bats in the tunnels from predators and human disturbance with special gates, bat counts, and monitoring the tunnels for white-nose syndrome – a disease that is devastating bats across the eastern U.S. They complemented these efforts by installing bat houses for summer roosting bats with the help of a local Eagle Scout troop and marking the boxes’ locations via GPS with local Cub Scouts.

Maiden Rock’s abandoned mine tunnels now provide the second-largest shelter for hibernating bats in the Midwest. Approximately 84,000 to 95,000 bats make these tunnels their home each winter.

The dedicated employees and volunteers at Maiden Rock didn’t stop there. They also took on the responsibility to manage the site’s grassland and forest areas. Their ongoing conservation efforts include managing for standing dead trees and constructing brush piles across 10 acres of forest, seeding native grasses and wildflowers on exposed areas and steep slopes, and creating successful partnerships with Saving Birds Thru Habitat and the local 4-H club to monitor nest boxes and plant bird-friendly trees.

Buoyed by the success of their efforts in and outside of the mine, the team also took ownership of a restoration project for nearby Pine Creek, which had slowly filled with sediment from poor agricultural practices and erosion and could no longer support eastern brook trout, which depend on clean water to survive. The Maiden Rock team’s restoration efforts included reshaping the creek bed, native plantings, adding rocks and logs, and stream monitoring. Ongoing invasive plant control now helps maintain the restoration.

Education is also a significant component of the Maiden Rock program, and the team works with teachers, natural resource experts, and other local groups to ensure that educational projects are engaging and informative. School groups learn about wildlife habitats through active participation, whether it be by helping to monitor the stream or build, install, and monitor the bat houses and nest boxes. Geology students from the University of Wisconsin-Eau Claire have participated in research on the composition of sandstone cement in the mine. Events such as the annual “Maiden Rock Bat Nights” and mine tours help spread understanding about the bats on site, their importance, and the threat posed by white-nose syndrome. The Maiden Rock team also visits local schools and participates in Maiden Rock Summerfest to educate the community about bats.

What started with protection of a bat cave resulted in a community-wide effort to restore and maintain precious surrounding wildlife habitat for a multitude of animals.

Related Content

• Blogs:
  • Celebrate Bats for Halloween
  • A Breakthrough Discovery About White-Nose Syndrome
  • National Bat Week 2014
  • Wildlife in Winter: Hibernation
• Webinars:
  • Bat Conservation on Your Corporate Landscape
• Project Guidances:
  • Bats Project Guidance

[factbox