His family thanked rescue workers in a statement that also identified Westenskow.
"We feel they did everything possible to rescue Devin, but that there was no way to get him out alive given the extent of his injuries and instability of the mine shaft," the statement said. "We are forever grateful for their efforts."
The decision to end the rescue came after two unsuccessful attempts by search teams to descend into the shaft, where Westenskow was trapped in debris, said Doran Sanchez, a U.S. Bureau of Land Management spokesman.
An attempt Thursday caused walls of the 100-plus-year-old shaft to crumble and rocks to fall on rescuers, he said.
"One individual was hit in the head by falling rock and it split his hard hat," Sanchez said. "You're talking about two of the best search and rescue squads in Nevada, and they finally determined there was no way they could safely rappel down."
Westenskow was given his last rites Friday. He was pronounced dead at 12:30 p.m. that day, after the Pershing County coroner's office determined he had stopped breathing by reviewing images from a video camera they had lowered into shaft, Sanchez said.
Word of the death was not released until Saturday because there was no cell phone service in the remote area for authorities to stay in contact.
"The family feels that if Jesus Christ was buried in a tomb, it's good enough for Devin," his grandmother, Lois Westenskow of Layton, Utah, told The Associated Press.
The video camera showed he had been breathing early Friday but not moving and had suffered serious head injuries. Images taken Thursday night revealed he had been moving his hands.
About 50,000 abandoned mine shafts have been identified as the most hazardous in Nevada, but the shaft where the man fell wasn't among them, BLM officials said.
The agency plans to permanently seal the shaft and several other openings in the area by Monday, Sanchez said.
The family statement said Westenskow was divorced and split his time between Evanston and Battle Mountain, Nev.
Sheriff's officials from Pershing and Lander counties oversaw the rescue effort, with assistance from rescuers from Washoe County, Newmont Mining Corp. and the U.S. Navy in Fallon.