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Innowacyjne rozwiązanie hydromechanicznego czyszczenia osadników wód dołowych w podziemnych wyrobiskach górniczych

Biel Bronisław

Mining – Informatics, Automation and Electrical Engineering

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2021

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R. 59, nr 4

26--30

PL

W kopalniach podziemnych woda pochodząca z naturalnych dopływów oraz woda technologiczna pochodząca głównie z sieci rurociągów przeciwpożarowych gromadzona jest w osadnikach znajdujących się najczęściej na najniższym poziomie kopalni. Zwykle jest to woda zanieczyszczona mechanicznie. Gromadzenie się osadu odbywa się na zasadzie sedymentacji. W artykule przedstawiono metodę oczyszczania osadników wód kopalnianych opartą na zasadzie hydrourabiania i hydrotransportu oraz sposób segregacji na część stałą, czyli osad, i wodę. Konsystencja otrzymanego osadu pozwala na jego transport, np. za pomocą przenośnika, a woda może być ponownie wykorzystana w procesie hydrourabiania osadu. Do tego celu stosuje się urządzenia z serii ZEKO.

EN

In mines, water from natural inflows as well as process water from fire protection systems is usually stored in sedimentation tanks, located primarily at the lowest level of the mine. Such water usually contains mechanical contaminants, undergoing the process of sedimentation. The article presents a method enabling the cleaning of mine water sedimentation tanks. The method involves jet mining, hydrotransport and segregation into sediment (i.e. the solid fraction) and water. The consistence of sediment obtained after segregation makes the former transportable (e.g. using an appropriate conveyor/feeder), whereas water can be reused subsequently in the jet mining of sediment. One of the solutions enabling the performance of the above-named process is a ZEKO series system

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Innovative hydromechanical cleaning of mine water sedimentation tanks in underground headings

Biel Bronisław

Mining – Informatics, Automation and Electrical Engineering

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2021

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R. 59, nr 4

21--25

EN

In mines, water from natural inflows as well as process water from fire protection systems is usually stored in sedimentation tanks, located primarily at the lowest level of the mine. Such water usually contains mechanical contaminants, undergoing the process of sedimentation. The article presents a method enabling the cleaning of mine water sedimentation tanks. The method involves jet mining, hydrotransport and segregation into sediment (i.e. the solid fraction) and water. The consistence of sediment obtained after segregation makes the former transportable (e.g. using an appropriate conveyor/feeder), whereas water can be reused subsequently in the jet mining of sediment. One of the solutions enabling the performance of the above-named process is a ZEKO series system.

PL

W kopalniach podziemnych woda pochodząca z naturalnych dopływów oraz woda technologiczna pochodząca głównie z sieci rurociągów przeciwpożarowych gromadzona jest w osadnikach znajdujących się najczęściej na najniższym poziomie kopalni. Zwykle jest to woda zanieczyszczona mechanicznie. Gromadzenie się osadu odbywa się na zasadzie sedymentacji. W artykule przedstawiono metodę oczyszczania osadników wód kopalnianych opartą na zasadzie hydrourabiania i hydrotransportu oraz sposób segregacji na część stałą, czyli osad, i wodę. Konsystencja otrzymanego osadu pozwala na jego transport, np. za pomocą przenośnika, a woda może być ponownie wykorzystana w procesie hydrourabiania osadu. Do tego celu stosuje się urządzenia z serii ZEKO.

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Wysokociśnieniowe urabianie węgla

Kalukiewicz A.

Archives of Mining Sciences

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2003

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Vol. 48, nr 4

481-501

PL

W artykule przedstawiono modele teoretyczne opisujące efektywność hydrourabiania na tle dotychczasowych doświadczeń z tym procesem. Autor przedstawił własne badania przeprowadzone w podziemnej kopalni wqgla kamiennego. Do hydrourabiania zastosowano instalacją własnej konstrukcji umożliwiającą wytworzenie strumieni o średnicach 0,8-1,2 mm, przy ciśnieniach 110-200 MPa. Uzyskane w trakcie badań wyniki pozwalają określić zagęszczenie siatki nacięć w celu wykruszania się urobku. Określono także energochłonność procesu i skład ziarnowy urobku. Wyniki badań pozwoliły zweryfikować zaproponowany bezwymiarowy model hydrourabiania wysokociśnieniowego.

EN

The paper provides an overview of theoretical models describing the efficiency of high-pressure water jet techniques, exploring the applications of this process to date. The idea of employing water as a rock cutting tool is a very old one. Observation of natural processes clearly showed the destructive actions of water jets, starting from processes in the micro-scale to full scale features such as the Grand Canyon in Colorado. Documented materials describing practical applications of high-pressure water jest date back to the 19th century. The method was employed to excavate clastic gold deposits in California, USA in 1853-1886 (Fig. \). High-pressure water jest found their way to Europe, too- in 1900 this method was introduced in Prussia and Russia. In qualitative terms the idea of employing water jets to rock cutting is not new, yet certain quantitative aspects - such as energy requirements and kinematics of water jets, particularly high-pressure water jets, place it among novel and unconventional mining techniques. The hydraulic rock cutting operation (using water jets mostly) involve the concentrated action of water jet with supersonic speed upon the surface to be machined. Hence considerable power densities delivered locally cause the micro-fragments of the material being crushed to be torn from its body mass. Several descriptions/models of high-pressure jet generation and its range of applications arc available in literature on the subject since it is extremely difficult to cover all phenomena existing in the water jet (water-air friction, turbulence, generation of shock waves). That is why information on water jet is obtained chiefly by way of empirical tests. The paper reviews several mathematical models developed experimentally in various research centres. One of the institutions that continued the research on hydraulic rock cutting was the Skoczyński's Mining Institute in Russia. Extensive experimental programs allowed for formulating most crucial relationships between jet parameters and cutting efficiency [after Kuzmich (Nikonov, Szawłowskij, Hynkin 1967; Nikonov, Kuzmich, Goldin 1986; Nikonow 1962], Eq (l)-(3). According to later works by LA. Kuzmich, G.P. Nikonov, J.A. Goldin, the depth of the cut in hard rocks is given by the formula (4). E. Pasche developed an empirical formula (5) determining the cut depth (Pasche 1981). S.C. Crow took into account cavitation processes (Crow 1973, 1974) and provided yet another formula defining the cut depth (6). G. Rehbinder (1977, 1980) used the theory of cavitation as the starting point and derived the formula (8). J. Vasek and L. Hlavac (Hlavac 1992; Vasek et al. 1991; Vijay, Brierley 1980) from HOU CSAV in Ostrava derived an analytical formula (9) to find the cut depth on the basis of existing models and fundamental equations of hydromechanics. All these developed models require that the operating conditions of the jet and properties of the material to be cut be precisely known beforehand, which seem to preclude their practical use as each application of a model would require extensive testing or a large number of parameters would have to be found. Laboratory tests on rock- model specimens revealed that small-diameter high-pressure water jets proved to be very effective tools. The further step involved testing the new technology in real-life conditions in underground coal mines. For that purpose a high-pressure cutting unit was designed and engineered in the AGH University of Science and Technology (see Fig. 2). It generates water jest of sufficiently high pressure (up to 200 MPa) and allows for jet manoeuvring to ensure effective coal cutting. In order to ensure a sufficiently large speed of nozzle displacement with respect to the rock, the assumption is made that it would move in a rotating motion and the turning radius be continuously controlled. Vertical and horizontal movements of a hydro-monitor with continuous speed control produce a network of cuts on the coal surface, as seen in Fig. 4. The size fractions of mined material obtained by way of hydraulic cutting were much more satisfactory than when conventional mining machines arc used (grade 0-10 mm - 7%, in excess of 100 mm - 36%), while the unit energy of the process remained on a low level Ejw = 1.24 kWh/Mg. During the tests there was no water in the excavations, so the mined material was only slightly wet. Dust levels inside the excavation were similar to those in the main gate and ventilation ducts where no mining operations are carried out. In terms of water jet applicability, the major parameter is the required density of cuts to be made on the rock surface in order to crush the rock portions between the adjacent cuts. Extensive tests in laboratory conditions and in situ were run in the mine M-300. As a part of this study, the problem of rock crushing between the cuts was thoroughly investigated (Kalukiewicz 1984). The crushing factor w = hw/h is shown graphically (h - depth of cut made by a water jet, hw - depth of rock crushing in between the cuts in relation to the distance between the adjacent cuts x). It is readily apparent that the crushing factor remains on a high level, nearing unity for x = 40-40 mm, then it rapidly falls down to zero, which means that rock is not crushed at all. It appears that coal mining with high-pressure jets only is possible and viable in terms of energy requirements. However, when any scam disruptions should appear, other tools, such as machining tools, have to be employed as well. Recent research work is focused on combined mining techniques utilising high-pressure jets as well as machine tools (i.e. high-pressure water jet assisted rock cutting). As it was mentioned in the introductory section, there are several major determinants of the high-pressure jet assisted cutting process and its mathematical description uses many difficult and mostly empirical coefficients. That is why a dimensionless model of the water assisted cutting process is suggested. The major advantage of the model is that it allows for selecting the operating parameters of cutter/cutting machines, hence it can be employed at the stage of cutter or cutter controller design. he model includes several formulas relating independent parameters, such as: pressure, time of penetration and velocity of jet displacement when it moves transversely to the operating line, displacement velocity and nozzle standoff distance to dependent variables: cut depth and unit energy. The cut depth g as the function of time t is expressed as (11) for rock penetrated by an immobile jet {tm - time constant, i.e. the time after which the maximal depth hmax is achieved by the jet of specified parameters, to be determined experimentally). The unit energy in time is given by (12). When rock is cut by a jet moving along the rock surface and the distance between the nozzle and rock surface remains the same, the depth of penetration will decrease with an increase in relative velocity of the nozzle motion along the rock mass. When the relative velocity is very small, the depth of penetration is maximal and in a certain range it remains independent of relative velocity variations. Accordingly, the depth of penetration hw given by (14) reaches its maximal value when vw tends to zero; when hw tends to zero, vw will tend to infinity. Unit energy as a function of nozzle displacement velocity is given by (15). In practical applications it is most useful to express the cut depth in the function of pressure as in that way cutting efficiency can be assessed in relation to jet pressure (16) and that pressure, apart from water delivery, determines energy requirements for the process and imposes some new requirements as to cutter design. These expressions and the relationships between the unit energy and pressure presents (17), where p is a parameter defined as pressure at which after the time t a hole in made in the rock to the depth hmax. When the jet moves with a constant velocity vw, the functional relationships between these quantities will be given as (19) - cut depth and (20) - specific energy variations in the function of pressure. When the nozzles moves away from the rock surface, the cut depth is reduced. For the distance l, much less than the effective jet length lj it is given by (21) where 1 stands for the total, effective jet length or the maximal cut depth for zero jet split. Analytical formulas expressing the relative cut depth and the relative unit energy of cutting arc graphed as curves in Fig. 9, 10, 11. Averaged values obtained by way of measurements being a part of numerous studies (Kalukiewicz 1984, 1986, 1993; Klich, Kalukiewicz 1990) are also indicated on relevant graphs. These values are indicated as points in the coordinate systems to verify the previously derived formulas. Hydraulic rock cutting as a mining technique has several advantages: - no sparking, - low dust levels, - water jet is not subject to wearing. However, high pressure water jet rock cutting requires very advanced equipment. Presently in mining practice high pressure water jet are combined with traditional machining tools (Summers, Barker 1978; Nikonov et al. 1967). In purely technical terms, however, a cutting machine utilising high-pressure jets only can be well designed.