The survey was done by researchers from Hebrew University’s Cave Research Center (CRC), in addition to Bulgaria and other nations.
“The Malham Salt Cave is a river cave,” said CRC director Amos Frumkin. “Water from a surface stream flowed underground and dissolved the salt, creating caves—a process that is still going on when there is strong rain over Mount Sedom about once a year.”
Malham was first discovered by the CRC back in the 1980s. Later, tens of CRC expeditions surveyed Mount Sedom and found more than 100 salt different caves inside, the longest of which measured more than 3.5 miles.
Carbon-dating tests showed the cave as around 7,000 years old with successive rainstorms creating new passages for cavers to explore. When international expeditions resumed at Malham in 2018 and 2019, their surveys discovered the cave’s record-breaking, double-digit length.
“Thirty years ago, when we surveyed Malham, we used tape measures and compasses,” said Frumkin. “Now we have laser technology that beams measurements right to our iPhones.”
“We cavers worked 10-hour days underground, crawling through icy salt channels, narrowly avoiding salt stalactites and draw-dropping salt crystals. Down there, it felt like another planet,” said CRC member Efraim Cohen. “Our next and final step is to map the tightest spots and the most difficult ones to reach. When we’re all done, it’s likely we’ll add a few hundred meters to Malham’s impressive 10-kilometer length.”