Boring is drilling a hole, tunnel, or well in the Earth. It is used for various applications in

geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people t ...

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is call ...

civil engineering Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewa ...

, and

mineral exploration Mining in the engineering discipline is the extraction of minerals from underneath, open pit, above or on the ground. Mining engineering is associated with many other disciplines, such as mineral processing, exploration, excavation, geology, and ...

. Today, most Earth drilling serves one of the following purposes: * return samples of the

soil Soil, also commonly referred to as earth or dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debri ...

and/or

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

through which the drill passes * access rocks from which material can be extracted * access rocks which can then be measured * provide access to rock for purposes of providing engineering support Unlike drilling in other materials where the aim is to create a hole for some purpose, often the case of drilling or coring is to get an understanding of the ground/ lithology. This may be done for

prospecting Prospecting is the first stage of the geological analysis (followed by exploration) of a territory. It is the search for minerals, fossils, precious metals, or mineral specimens. It is also known as fossicking. Traditionally prospecting rel ...

to identify and quantify an ore body for mining, or to determining the type of foundations needed for a building or raised structure, or for underground structures, including tunnels and deep basements where an understanding of the ground is vital to determining how to excavate and the support philosophy. Drilling is also used in vertical and inclined shaft construction.

History

Borehole drilling has a long history.

Han dynasty The Han dynasty (, ; ) was an imperial dynasty of China (202 BC – 9 AD, 25–220 AD), established by Liu Bang (Emperor Gao) and ruled by the House of Liu. The dynasty was preceded by the short-lived Qin dynasty (221–207 BC) and a warr ...

China (202 BC – 220 AD) used deep borehole drilling for mining and other projects. Chinese borehole sites could reach as deep as 600 m (2,000 ft).* Loewe, Michael. (1968). ''Everyday Life in Early Imperial China during the Han Period 202 BC–AD 220''. London: B.T. Batsford Ltd.; New York: G.P. Putnam's Sons, p. 194.

Methods

When drilling in stone, one must pay particular attention to the type of material. There are three different classifications of drill bits used for drilling into stone: soft, medium, and hard. Soft formation rock bits are used in unconsolidated sands, clays, and soft limestones, etc. Medium formation bits are used in

dolomites The Dolomites ( it, Dolomiti ; Ladin: ''Dolomites''; german: Dolomiten ; vec, Dołomiti : fur, Dolomitis), also known as the Dolomite Mountains, Dolomite Alps or Dolomitic Alps, are a mountain range located in northeastern Italy. They form pa ...

limestones Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when t ...

, and shale, while hard formation bits are used in hard shale,

mudstones Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' ...

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...

and other hard and/or abrasive formations. Soft ground drilling can be undertaken using a rotary auger or wash boring techniques, while rock drilling often use methods such as NMLC which allow for recovery of a core of material which can be examined to determine the strength, degree of weathering, understanding of any how intact the rock is ( RQD) and identify any discontinuities or other planes of weakness. Testing of the material in

borehole A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petrol ...

s is also possible. In soft ground the

standard penetration test The standard penetration test (SPT) is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil. This test is the most frequently used subsurface exploration drilling test performed ...

can be used to determine the strength of the material. In rock in-situ stress testing using

hydrofracturing Frost weathering is a collective term for several mechanical weathering processes induced by stresses created by the freezing of water into ice. The term serves as an umbrella term for a variety of processes such as frost shattering, frost wedg ...

or overcoring,

Acoustic Televiewer Acoustic may refer to: Music Albums * ''Acoustic'' (Above & Beyond album), 2014 * ''Acoustic'' (Deine Lakaien album), 2007 * ''Acoustic'' (Everything but the Girl album), 1992 * ''Acoustic'' (John Lennon album), 2004 * ''Acoustic'' (Love Amo ...

can be used to map discontinuities to determine their orientation. It is also possible once a borehole is complete to measure the permeability. Samples of water and material are also taken for examination and lab testing.

Superdeep Borehole

In 1961 the United States began

Project Mohole Project Mohole was an attempt in the early 1960s to drill through the Earth's crust to obtain samples of the Mohorovičić discontinuity, or Moho, the boundary between the Earth's crust and mantle. The project was intended to provide an eart ...

, an ambitious attempt to drill through the Earth's crust into the Mohorovičić discontinuity. The project was discontinued due to high cost. The

Kola Superdeep Borehole The Kola Superdeep Borehole (russian: Кольская сверхглубокая скважина, translit=Kol'skaya sverkhglubokaya skvazhina) SG-3 is the result of a scientific drilling project of the Soviet Union in the Pechengsky District ...

was a similar project of the

USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...

in the 1970s and early 1980s the

attempted to drill a hole through the crust, to sample the Mohorovicic Discontinuity. The deepest hole ever drilled failed not because of lack of money or time, but because of

rock physics Petrophysics (from the Greek πέτρα, ''petra'', "rock" and φύσις, ''physis'', "nature") is the study of physical and chemical rock properties and their interactions with fluids. A major application of petrophysics is in studying reservoi ...

at depth. At approximately 12,000 metres depth, rock begins to act more like a

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

solid than a rigid solid. Rock temperatures of several hundred degrees Celsius, required that the

drilling fluid In geotechnical engineering, drilling fluid, also called drilling mud, is used to aid the drilling of boreholes into the earth. Often used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are als ...

refrigerated The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...

before being sent to the cutting face of the drill. As the drill bits burnt out and were removed for replacement, the hole simply flowed closed, and the rock had to be re-drilled. The hole was scrapped. Further attempts are planned by American consortia and further

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...

n attempts in

Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...

Ice boring

Ice cores are drilled by hollow bits, in much the same way that sediment cores are drilled. When all that is needed is the hole, hot water drill technology may be used to melt holes in ice or snow for both Arctic and Antarctic research purposes. Equipment for such a method is also lightweight when drilling deep holes, compared to traditional drilling equipment. Hot water drilling has been used successfully in the

IceCube Neutrino Detector The IceCube Neutrino Observatory (or simply IceCube) is a neutrino observatory constructed at the Amundsen–Scott South Pole Station in Antarctica. The project is a recognized CERN experiment (RE10). Its thousands of sensors are located under ...

and Antarctic Muon And Neutrino Detector Array projects to drill as deep as 2,450 meters.

References

{{Reflist

External links