Final answer:
The Kola Superdeep Borehole is the world's deepest borehole, located on the Kola Peninsula, with a depth of approximately 12 kilometers. Drilling stopped before reaching the goal of 15 kilometers due to technical challenges.
Step-by-step explanation:
The world's deepest borehole is named the Kola Superdeep Borehole. Its location is on the Kola Peninsula, near the Russian border with Norway and Finland. The borehole reaches a depth of approximately 12 kilometers (7.5 miles) beneath the Earth's surface. Drilling of this hole began in the 1970s under Soviet leadership, with the primary goal to explore the Earth's crust. However, drilling stopped due to technical challenges which prevented the team from going deeper, with the ultimate project goal being 15 kilometers.
While the deepest mine is less than 4 kilometers deep, the Kola Superdeep Borehole remains as an unmatched achievement in drilling. Geothermal energy extraction, often discussed alongside deep drilling, presents sustainability issues due to the depletion of heat near each borehole and necessitates frequent re-drilling to maintain energy production. This makes the idea of a global geothermal network reaching 50 kilometers down a challenging prospect.