page_title: Kola Superdeep Borehole
section_title: Making the hole
hierarchical_section_title: Kola Superdeep Borehole / Making the hole
caption_attribution_description: English: A USSR stamp, Science in USSR. Date of issue: 25th November 1987. Designer: A. Kernosov Michel catalogue numbers: 5774-5776. 10 K. deep dull green, blue-black and azure. Kolskaya borehole Русский: Марка СССР Исследование строения и состава земной коры (1987, ЦФА №5892).
context_page_description: The Kola Superdeep Borehole was a very deep hole dug on the Kola Peninsula in Russia during 1970-1992 and closed by 2008. It was dug in order to learn more about the inside of the Earth. Digging started on May 24, 1970. The work continued until 1992, or 1994. The borehole was kept open until 2005. SG-3, the deepest part of the hole, reached 12,261 meters or 7.6 miles below the surface in 1989. That is the deepest hole ever made and is still the deepest man-made point on Earth.
  For a long time, SG-3 was also the longest hole by distance from its opening. In 2008, the Al Shaheen BD-04A oil well in Qatar reached +27 meters or 89 feet farther and, in 2011, the Odoptu OP-11 oil well off Sakhalin got +83 m or 272 ft farther.
context_section_description: The hole was made with different machines at different times. The Soviets started making the hole with the Uralmash-4E. Later, they used the Uralmash-15000. At first, they wanted to get to 15,000 m or 9.3 mi below the surface. The machines broke the earlier record for the deepest hole on June 6, 1979. The prior record had been held by the 9,583-meter (31,440 ft) Bertha Rogers hole in Washita County, Oklahoma, in the United States. The machines got to 12,000 m or 7.5 mi below the surface in 1983. Then the Soviet Union celebrated (took special note of) this for about a year without going any deeper. On September 27, 1984, the machine broke at a depth of 12,066 m or 39,587 ft; its drill string twisted off and was left in the hole. When the Soviets started to make the hole again, they had to start from 7,000 m (23,000 ft).
  The greatest depth was reached in 1989. The people making the hole thought that they would get to 13,500 m (8.4 mi) by the end of 1990 and, at last, get to 15,000 m by 1993. They were not able to go any deeper, though, because they had made an error, and the end of the hole was 180 °C or 356 °F in place of the 100 °C or 212 °F they had hoped for. Their machines stopped making any holes at all in 1992. The last studies were stopped in 2005 and the place was completely closed and left alone in 2008.
caption: A Soviet stamp from 1987 with a picture of the hole.
exif: {"Image Orientation": "0", "Image XResolution": "800", "Image YResolution": "800", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop 7.0", "Image DateTime": "2007:09:26 12:43:49", "Image ExifOffset": "154", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "290", "Thumbnail JPEGInterchangeFormatLength": "5913", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "560", "EXIF ExifImageLength": "800"}