US

Searchers scouring Wisconsin mine 'maze' for missing boys

  • This undated photo provided by the Dade County Sheriff's Office in Juneay, Wis., shows from left, Zachary Heron, Tate Rose and Samuel Lein. Authorities are focusing their search for the three missing teenage boys at an abandoned iron mine near Iron Ridge in southern Wisconsin. Dodge County sheriff's officials say the boys were last seen Sunday afternoon, July 10, 2016. (Dade County Sheriff's Office via AP)

    This undated photo provided by the Dade County Sheriff's Office in Juneay, Wis., shows from left, Zachary Heron, Tate Rose and Samuel Lein. Authorities are focusing their search for the three missing teenage boys at an abandoned iron mine near Iron Ridge in southern Wisconsin. Dodge County sheriff's officials say the boys were last seen Sunday afternoon, July 10, 2016. (Dade County Sheriff's Office via AP)  (The Associated Press)

  • This undated photo provided by the Dade County Sheriff's Office in Juneay, Wis., shows from left, Zachary Heron, Tate Rose and Samuel Lein. Authorities are focusing their search for the three missing teenage boys at an abandoned iron mine near Iron Ridge in southern Wisconsin. Dodge County sheriff's officials say the boys were last seen Sunday afternoon, July 10, 2016. (Dade County Sheriff's Office via AP)

    This undated photo provided by the Dade County Sheriff's Office in Juneay, Wis., shows from left, Zachary Heron, Tate Rose and Samuel Lein. Authorities are focusing their search for the three missing teenage boys at an abandoned iron mine near Iron Ridge in southern Wisconsin. Dodge County sheriff's officials say the boys were last seen Sunday afternoon, July 10, 2016. (Dade County Sheriff's Office via AP)  (The Associated Press)

Wisconsin authorities say an abandoned mine where they're searching for three missing boys is a labyrinth of tunnels that goes on for miles.

Dodge County Sheriff Dale Schmidt described the Iron Ridge mine to reporters during a news conference Monday as a vast maze of interconnected tunnels that goes on for four miles. He says it would be easy to get lost in the tunnels without a compass.

The three boys — Tate Rose and Zachary Heron, both 16, and 15-year-old Samuel Lein — were last seen Sunday. Schmidt said their bikes were found off a road near an entrance to the mine.

Searchers are using dogs and thermal imaging.

The mine is owned by the University of Wisconsin-Milwaukee, which says an estimated 100,000 bats live there.