ISSN 1062-7391, Journal of Mining Science, 2017, Vol. 53, No. 5, pp. 837–847. © Pleiades Publishing, Ltd., 2017.
Original Russian Text © N.G. Kyu, 2017, published in Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, 2017, No. 5, pp. 44–56.
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Characteristics and Problems of Rock Fracturing by Fluids
N. G. Kyu
Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences,
Novosibirsk, 630091 Russia
Received December 1, 2016
Abstract—Fracturing efficiency of fluids in specific mining processes depends on reliability of data on
structure and state of rocks, on pre-setting the location of fracturing origin, on choice of a fluid and its injection
regime, as well as on the accepted engineering solutions. Fracturing by fluids are the processes that alter
properties, structure, composition and state of rocks. Investigation of such processes offers a deeper insight
into the multi-phase media (earth crust) and promotes advancement in nonconventional mining technologies.
Keywords: Fracturing by fluid, stress raisers, brittle failure, hole sealing, fluid injection, longitudinal and
transverse fractures, plastic substances, fluid fracturing control.
Fracturing by fluids means rupture of a medium under the action of pressure of a fluid penetrating
it. A fluid is a substance capable to transform without internal disintegration (voids, cavities). Fluids
can be solid (wax, plasticine, lead), liquid, gaseous or be composed of many phases (solid–liquid–gas
mixture). Generally, fracturing by fluids is a multi-parameter process of a medium-and-fluid
interaction at the nonlinear and undetermined, as a rule, relationship of the parameters.
Rock fracturing by fluids of different rheology is a frequent natural phenomenon. It occurs at great
depths and on the ground surface. A fluid makes a facture (slot) and fills it. The fracture may be of
simple or irregular shape, from millimeters to tens and hundred kilometer long.
Fluid-induce rupture begins at points of stress concentration. First, an incipient crack appears, and
fluid flows in it and presses on its faces. Tensile forces enable the fracture grow until the fluid
pressure in the crack lowers down to a critical value governed by the properties and occurrence
conditions of rocks, rock pressure and the fracture size. In a uniform monolithic medium under stress
where all components are equal initially, fracturing by fluid takes place in the plane of a preliminary
Fracturing by fluids is accompanied by various physical and chemical processes, in wide ranges of
temperature, pressure and properties of fluids and rocks. During these processes, elastic and
electromagnetic energies are emitted, inter-atomic and inter-molecular bonds are broken, fluids enter
chemical reaction with the newly generated surfaces in rocks, environment undergoes chemical
transformations, gases are released and absorbed, new substances appear with a range of properties
and stresses are redistributed in rocks.
Fluid-induced ruptures, alongside the other natural phenomena, have influence on formation of
streaks, veins and dykes in rock mass, where crystals, ore and other valuable materials may occur. It
is likely that mountain ridges are the consequences of magma inrush in the earth crust in the course of
fluid fracturing. Currently, there are long fractures (slots) in the bottom of the oceans, and fluent lave
erupts from them and makes hills. Some times fracturing by fluid induces such dynamic events as
volcanic eruptions and rock bursts.