Kola Superdeep Borehole

Kola Superdeep Borehole

Superstructure of the Kola Superdeep Borehole, 2007
Location
Kola Superdeep Borehole Location of the borehole in Murmansk Oblast, Russia Show map of Russia Kola Superdeep Borehole Kola Superdeep Borehole (Murmansk Oblast) Show map of Murmansk Oblast
Location	Pechengsky District
Province	Murmansk Oblast
Country	Russia
Coordinates	69°23′47″N 30°36′36″E / 69.3965°N 30.6100°E / 69.3965; 30.6100
Production
Type	Scientific borehole
Greatest depth	12,262 metres (40,230 ft)
History
Opened	1965
Active	1970–1983 1984 1985–1992 1994
Closed	1995

The Kola Superdeep Borehole SG-3 (Russian: Кольская сверхглубокая скважина СГ-3, romanized: Kol'skaya sverkhglubokaya skvazhina SG-3) is the deepest human-made hole on Earth, which attained maximum true vertical depth of 12,262 metres (40,230 ft; 7.619 mi) in 1989.^[1] It is the result of a scientific drilling effort to penetrate as deep as possible into the Earth's crust conducted by the Soviet Union in the Pechengsky District of the Kola Peninsula, near the Russian border with Norway.

SG (СГ) is a Russian designation for a set of superdeep (Russian: сверхглубокая) boreholes conceived as part of a Soviet scientific research programme of the 1960s, 1970s and 1980s. Aralsor SG-1 (in the Pre-Caspian Basin of west Kazakhstan) and Biyikzhal SG-2 (in Krasnodar Krai), both less than 6,810 metres (22,340 ft) deep, preceded Kola SG-3, which was originally intended to reach 7,000 metres (23,000 ft) deep.^[2] Drilling at Kola SG-3 began in 1970 using the Uralmash-4E, and later the Uralmash-15000 series drilling rig. A total of five 23-centimetre-diameter (9 in) boreholes were drilled, two branching from a central shaft and two off of one of those branches.

In addition to being the deepest human-made hole on Earth, Kola Superdeep Borehole SG-3 was, for almost three decades, the world's longest borehole in measured depth along its bore, until surpassed in 2008 by a hydrocarbon extraction borehole in Qatar.^[3]