The Biggest Man-Made Hole On Earth: Kola Borehole In Russia
Kola Bore Hole: The Biggest Man-Made Borehole
The project began with Uralmash-4E drilling rigs on May 24, 1970. In 1979, they upgraded to Uralmash-15000 series drilling rigs. By 1989, they had drilled the deepest hole, reaching 12,262 meters (40,230 feet). This Kola bore hole remains the deepest and biggest man-made hole.
The goal was to drill as deep as 9 miles into the Earth. However, the project was abandoned when they encountered unexpectedly high temperatures. Approximately 7.5 miles below the surface, rocks were found to be around 180 degrees Celsius. The drillers had expected high temperatures but not this extreme. Over time, the drilling machinery began to deform due to the heat. According to the researchers, the rocks at these depths were more like plastic than solid rock.
