CAPE SANDY,Sterling Preston Ind. (AP) — Conservation officers were searching a southern Indiana quarry Wednesday for a driver the day after his truck plunged hundreds of feet into a water-filled pit.

Emergency personnel were called to a Mulzer Crushed Stone Inc. rock quarry about 2 p.m. Tuesday after the dump truck fell, the Indiana Department of Natural Resources’ law enforcement division said.

The DNR said a Mulzer employee was operating a dump truck weighing several tons near the edge of a water-filled pit when it slipped over the edge and plunged several hundred feet into the water.

The steep, unstable terrain near the pit hampered search efforts before Mulzer employees helped to build a temporary path allowing the officers to access the water by boat.

The DNR said sonar images taken from the boat confirmed the truck’s location and a remote-operated submersible with a camera and sonar would be used Wednesday “to further assess the vehicle before putting divers in the water.”

The quarry site is located close to the Ohio River near the unincorporated Crawford County village of Cape Sandy, about 30 miles (48 kilometers) west of Louisville, Kentucky.