BREWSTER, N.Y. (CBSNewYork) — An avid scuba diver from New Jersey died doing what he loved – diving in the flooded former Tilly Foster iron mine in Putnam County.

On Monday afternoon, the man’s body was found, a day after friends saw him go in – and never come out.

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As CBS2’s Lisa Rozner reported, friends said Jersey City resident Bob Thomas was an experienced technical diver who dove into the waters of a former mine in Brewster dozens of times. On Sunday at noon, he was with two other divers when he went in for what should have been a 90-minute expedition.

When he did not show for a party, his girlfriend called police.

“The search was commenced in earnest this morning. High-tech sophisticated sonar equipment and cameras — deep-water cameras were brought in that were used remotely from the surface to search the mine shaft,” said Putnam County Sheriff’s Office Capt. William McNamara.

Around 1 p.m., a deep-water camera located the body of Thomas, 48, and a team of about 20 first responders used a cable to pull him out. The Putnam County sheriff’s office said he was tangled in wires.

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“The bottom of the cavern is littered with things like wrecked cars; old mining equipment,” McNamara said. “You have these items, you know, jagged edges.”

Fellow divers were too distraught to go on camera, but said Thomas never went beyond his limits and believe his death was an accident.

The sheriff’s office said the mine is about 600 feet deep. Thomas was found 170 feet below the surface where friends say he planned to dive.

“It’s basically diving done at very deep levels under very difficult conditions, requiring special expertise, training, experience and equipment,” McNamara said.

Friends said Thomas had been diving for 20 years. He and other divers had an agreement with owners of the property to dive at the mine.

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He is remembered as an upbeat man whose passion was helping people and diving.