Deep inside an abandoned mine in the Krusne hory (Ore Mountains) of northwest Czech Republic, Jakub Kristek's radiation meter crackles with urgency as he picks up a fist-sized rock. "Uranium ore," he says, pointing out the speckles of green minerals glinting under his headlamp before returning the rock to its pile.
Kristek is one of a handful of amateur minerologists whose search for rare minerals has uncovered a series of secret mines that date back to the Soviet Union's unquenchable thirst for uranium at the beginning of the nuclear arms race.
After America devastated Japan's Hiroshima with a nuclear bomb in August 1945, Soviet leadership pinpointed uranium as "the most important strategic raw material" of the new era. In November that year, the Soviet Union signed a secret agreement with Czechoslovakia to massively expand mining "for ores and concentrates that contain radium and other radioactive elements" within the mineral-rich mountains of the Bohemian massif.
The Soviet-Czechoslovak venture to extract uranium began with the Kremlin sending advisers and tonnes of food to bolster Czechoslovak miners. But after Soviet-backed leftists seized power in Prague in 1948, Stalin's Kremlin was free to operate with a heavier hand. Czechoslovak miners being paid handsomely to dig for uranium were soon outnumbered by criminals and political dissidents forced to do the same.
Tomas Bouska is the founder of Politicti vezni, an organization preserving the memories of Czech political prisoners. He told RFE/RL that amid "uranium fever" in the Soviet Union, the historic mining town of Jachymov was sealed off to anyone without official clearance to enter, then "one year after communists arrived to power [in 1948] they turned it into a real gulag colony prison colony."
Tens of thousands of prisoners were sent into the mines of Jachymov, where they labored amid clouds of radioactive dust. "There was no ventilation and we didn't have any respirators or masks," one survivor recalled, "so we left each day gray or red depending on the uranium ore that was being processed."
Several former inmates described the notorious "Russian buses"that illustrate the conditions of the camps. Ahead of a shift in the mines, hundreds of prisoners would assemble in their prison yard, then, as one survivor describes it, "We had to come together so that we would be touching each other's hips and bodies. Then [the guards] went around us with a steel rope, which was about 5 millimeters thick and locked this with a padlock." The mass of men would then shuffle as one toward the mine entrance.
The prisoners used hand tools, as well as explosives to remove hunks of radioactive ore. In the Ore Mountains mine, Kristek points out a concrete safe where he says detonators were kept "so the prisoners couldn't access them." Violence inside the mines were commonplace and some prisoners recall robbing paid miners for their hauls of radioactive ore in order to reach daily quotas.
For Kristek, exploring Cold-War era uranium mines is less about uncovering the Soviet infrastructure than the unique conditions inside. Radioactive underground caverns can create novel minerals within a few decades.
Kristek, who has had four scientific articles published on his mineral discoveries and is awaiting confirmation of others through lab tests, knows firsthand the dangers of abandoned mines. One nearly crushed him when he was a teenager.
"I was alone and digging to access an old mine, and the entrance collapsed on top of me," he recalls. "My head and one arm were free so I was able to dig myself, out but it was really scary." Today the father of one risks solo expeditions only occasionally. "I find the space and the silence creepy," he says. "Sometimes I sing out loud when I'm down there."
The minerology scene is small and tight-knit in the Czech Republic, but Kristek says some criminal elements have been known to work underground. "People are literally mining in some abandoned mines, and they're very hostile to other groups." In the historic mining town of Krupka in the country's northwest, he says, "there was a big tin deposit still there and these [illegal miners] were extracting it."
It is unknown if uranium is being extracted illegally, but Kristek says given the massive processing requirements of radioactive material it is highly unlikely.
Finding the mine entrances, which in some cases resemble large animal burrows, is achieved through a combination of studying maps and historical aerial photos, and knowledge passed down from former miners.
By the early 1960s most labor camps around Czechoslovakia’s uranium mines were closed, then demolished, and many mines closed. After Stalin's rule, the Kremlin had learned forced labor made little economic sense. Prisoners needed to be housed, fed and guarded around the clock and were less motivated than paid workers.
Inside mines abandoned in the 1960s, wooden supports have long since rotted away. Roof collapses can be seen in sections of the mine, making exploring them today a nerve-wracking experience, even for seasoned explorers.
"A collapse is the worst thing because there's nothing you can do about it," Kristek says, referencing one Czechoslovak explorer who was buried under falling rocks inside a mine in Jachymov and whose body was never recovered.
Kristek says he's glad to have explored so much of the history-haunted spaces while they remain accessible. "The more time passes, the more of these mines will collapse and be lost forever."
