A man living in an abandoned ghost town in California has opened up a sealed mine shaft, which he reckons hasn't been explored since 1878.

Brent Underwood is a resident of Cerro Gordo, a mining town famous for silver and lead, which was one of the most prosperous locations for the pair in its heyday.

The ghost town boomed after opening in 1865, with more than 4,000 miners living at the site, according to Underwood. It was closed in 1957 and has since been abandoned, but during the pandemic it acquired a new resident, Underwood.

Entrepreneurs Underwood and Jon Bier bought the town for $1.4 million in 2018. After the former visited in March 2020, the pandemic and a snowstorm saw him take up permanent residence at the site.

In the months since unexpectedly relocating to the town from his home in Austin, Texas, Underwood has been sharing numerous videos as he explores the sprawling mine network. There's some 30 miles of tunnels beneath the rock, with the deepest mine shafts 1,100 feet deep.

Armed with climbing equipment and a camera, he's descended to numerous levels but decided to open up a sealed mine shaft in his latest adventure.

Underwood shared a clip to his TikTok account, @brentwunderwood, in August, showing a digger scooping out dirt to reveal the long-forgotten entrance to the collapsed mine.

"This mine hasn't been opened in 100 years," the on-screen caption says, as he narrates the exploration, which can be seen here.

"We're opening up a mine shaft which has been collapsed for almost 100 years. This mine shaft hasn't been walked in in a very long time. Further back in the mine there's this hole deeper down," he says as he rappels down.

Finding artifacts from 1878 😳 #abandoned #TikTokFormats #TikTokPartner #abandonedplaces #treasure

Underwood lands on a partially decomposed animal, as he joked the mine is "full of surprises" in the clip, viewed more than a million times.

He continued: "Further back in the mine there's all sorts of old dynamite. When old dynamite crystalizes it can be very dangerous, so I left that there. Then I found this graffiti, which is done by carbide which came in tins like this."

In a second part, uploaded a day later, Underwood explored more of the "untouched level" of the mine, captioning the clip "finding artifacts from 1878."

Filming his surroundings, Underwood said: "This is an abandoned mine that we're opening up for the first time in 100 years. Further back in the mine there's another level 100 feet down but no ladder to get there. The glowsticks are to see how far down it was. I rappelled down and started exploring a section not touched in a very long time.

Opening up a collapsed mine and exploring inside #abandoned #TikTokFormats #TikTokPartner #abandonedplaces

"Right away I found this newspaper from 1878, showing how long it's been since people have explored here. Then there's this old dynamite box, from The Giant Powder company, next to it, actually dynamite. Not used in 150 years. Then I found this, which was used to drill holes for the dynamite and blasting cap tins, which can be very dangerous."

The video amassed more than 12 million views, and is one of the most popular on his channel, which documents his other mine explorations.

In his expeditions he's found silver ore—claiming $500 million was mined out of the rock when it was operational—as well as sacks used for transportation, bits of clothing, bats, tools and even the powder room where they used to store the explosives.

Explaining more about the graffiti, which includes signs for the toilet and a drawing of a goose, Underwood said in the comments: "They'd use the burnt carbide from their headlamps. So that's like 150-year-old graffiti."

In some parts of the mine the only way to descend down to the 700-foot level is by using the original wooden cage and hoist, dating from the 19th century.

Commenting on the most popular clip, Slimebby joked: "I remember this horror movie."

"I cannot wrap my brain around people digging and working in that in the 1800s. It is mind boggling," Pfeifyy wrote.

While Babaramdass commented: "Wow man, high anxiety watching that, way too claustrophobic."

On his YouTube account, Underwood said: "My hope is to breathe life back into this town. My goal one day is to allow more people to come and stay overnight.

"Restoring an abandoned ghost town with no running water is a long process with many ups and downs, but I wouldn't trade it for the world."

Newsweek reached out to Underwood for comment.

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