An experienced diver lost his life while scuba diving in the Hudson Valley.

On Monday just before 1 p.m., the body of a missing diver, Robert Thomas, 48, of Jersey City, N.J., was found by members of the New York State Police dive team.

According to the Putnam County Sheriff's Office, the dive team used sophisticated sonar and camera equipment to find the body at a depth of about 171 feet. They then lowered a cable from the surface, attached the cable to the body and lifted it out of the water.

Thomas went diving with two friends Sunday afternoon in waters at the site of the former Tilly Foster Mine, sometimes referred to as Simon’s Quarr, located off Old Mine Road in the Town of Southeast.

Police were told that Thomas dove into the water around noon and another man went in about an hour later. A female friend remained on the surface.

The other man surfaced around 3 p.m., but Thomas did not emerge, police say.

Police were also informed that Thomas is a very experienced technical diver who has gone diving in the mine many times in the past.

Just before 4 p.m., the Putnam County Sheriff’s Office received a telephone call from Thomas’ girlfriend who reported that Thomas went diving at the mine and was late for a party at her house in Queens.

A sheriff’s deputy searched the area and found Thomas’ friends, who told the officer that Thomas was late in surfacing from his dive, given his air supply

A preliminary investigation indicates that Thomas likely got stuck in wires or cables on the bottom of the flooded mine shaft, police say. The old mine is filled with water ranging in depths from 175 to 600 feet, and the bottom is littered with wrecked cars and trucks, old mining equipment and other debris.