RENO, Nev. - Rescuers ended an attempt to reach a man who was still alive after falling into a deep, unstable mine shaft in Nevada, saying Friday the effort posed too great a risk to people trying to descend into the pit.

A video camera determined the man was still breathing after plunging 190 feet into the shaft on Wednesday in Jersey Valley, northeast of Reno.

A priest had given last rites.

"The mine is so unstable that walls were crumbling and rocks were hitting rescuers on the head when they tried to reach him," JoLynn Worley, a spokeswoman for the U.S. Bureau of Land Management, told The Associated Press. "They're people who will make every effort to save someone, but they really can't get to him. It would endanger the lives of rescuers."

The name of the 28-year-old man from Battle Mountain wasn't immediately released.

The video camera showed the man was breathing but not moving and had suffered serious head injuries. Images taken Thursday night revealed he had been moving his hands.

Authorities intended to keep monitoring the mine shaft until the man stopped breathing, Worley said.

"I know some of his family members were out there," she said.

The man was working in the area with a geothermal drilling crew and visited the shaft with two friends during off-hours.

The shaft is among 10 such openings in the Murphy Mine Complex in Pershing County that originally was mined around 1895 and was last worked in 1945, Worley said.

From 265,000 to 310,000 abandoned mine shafts and openings are scattered across Nevada, she said, and federal and state agencies have an ongoing advertising campaign urging the public to stay away because of the danger.

About 50,000 abandoned mine shafts have been identified as the most hazardous, but the shaft where the man fell wasn't among them, Worley said.

Authorities have been closing shafts that pose the most danger near urban and recreation areas.

"People's curiosity sometimes gets the best of them," she said. "These were way out in the middle of nowhere where few people would venture."