Finland's Deepest Hole on Record
Appliion: Geothermal DeepRock Wells: Loion: Otaniemi, Espoo Finland: Hammer: Numa Patriot 185 125 Hammers: Bit: Conventional DTH Bits with PCD and Retainers: Hole Size: From 26 to 12 inches (656 to 305 mm) Depth or Length: 15,092 feet (4,600 meters) Deep: Formation: Granite (up to 520 MPa hardness) Rig Type : Hydraulic HerrenKnecht German .