共查询到20条相似文献，搜索用时 224 毫秒
1.
| 1. |
The technical parameters of coals of the grades K and K2 have been studied during working of the excavation pillar by eastern long-wall faces 4 and 5.
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| 2. |
Statistical characteristics of variation series were obtained.
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| 3. |
Maps of isolines representing the “principal relief forms” have been compiled, which describe the regularities of distribution
of the technical parameters.
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| 4. |
The variations of these parameters were examined in three directions relative to the axis of the well used for multiple hydraulic
treatment of a predegassed seam.
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Moscow Institute of Mining. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Polyznykh Iskopaemykh, No. 6, pp. 84–91,
November–December, 1990. 相似文献
2.
Conclusions
| 1. |
The ultimate size of bubbles in a flotation cell is an outcome of competing processes: coalescence of bubbles and adsorption
of the surfactant on their surface.
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| 2. |
Formation of highly developed initial interface due to breakup of the gas phase is an indispensable condition for stabilizing
bubble size at a lower size level.
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| 3. |
The optimal method of frothing agent injection (for stabilizing bubble size) into the flotation cell is to inject it into
the air phase as vapors or aerosols.
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Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, Vol. 34, No. 3, pp.101–107, May–June, 1998. 相似文献
3.
The hydrogeomechanical problems of mining are considered, which deal with rocks and ground water as a single mechanical system.
Among these problems are the openpits slopes stability, rocks consolidation and surface subsidence due to ground water level
lowering, water inrushes into mine workings, rock bursts prevention by using the water injection into the advance boreholes,
etc. The paper contains the basic theoretical grounds, as well as in-situ and laboratory methods for the investigation of
these processes.
The combined study of ground water regime and rock deformations has resulted in the theoretical substantiation of the hydrodynamic
and geomechanical processes within the scope of unique scientific direction-hydrogeomechanics (Mironenko, 1974). The hydrogeomechanical
models are widely used now for the analysis and forecasting the extremely important processes connected with the safe and
efficient mining operations, as well as with the protection of geological medium. Among these processes are:
| – |
o deformations of the open-pit slopes and spoil dumps;
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| – |
o consolidation of rocks due to the ground-water pressure drop;
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o water-and-rock material inrushes into mine workings caused by deformations of the undermined rock mass;
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o geodynamical processes due to the changes in ground water regime;
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o artificial hydrofracturing in rocks;
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o transformations of clay linings under the tailing ponds and other technical water basins
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相似文献
4.
| 1. |
A working and a rock mass around it may be defined by one dimensionless parameter λ≥0. This parameter predetermines the behavior
of the rock mass with any changes of mine pressure and support resistance.
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| 2. |
With 0≤λ<1 prediction of the behavior is clear: Reaction of the rock mass to any changes in mine pressure and support resistance
will have a stable character.
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| 3. |
If λ>1 then stability for the reaction is only retained up to a certain critical condition. Parameters of the critical condition
depend on mine pressure, the degree of weakening at contacts between blocks, geometrical dimensions and elasticity moduli.
With a changeover through the critical condition there is uncontrolled dynamic release of potential elastic energy for the
rock mass.
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Institute of Mining, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 37–43, January–February, 1991. 相似文献
5.
| 1. |
The sufficiently high reliability of the standard (k-ε) model for the Reynolds-stress in calculating the velocity field in
plane chamber-like mine workings has been demonstrated.
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| 2. |
A version of the velocity-field calculation in plane chambers by the Smagorinskii model has been proposed, using the (k-ε)
model in the preliminary stage, so as to permit considerable reduction in computer time.
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| 3. |
The most rational finite-difference schemes for approximation of the advection term in the turbulent-diffusion equation when
estimating the air transfer in plane chamber-like workings have been recommended:
| a) |
for periodically acting localized sources of impurity ejection, scheme VII (Table 2);
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| b) |
for discharge emissions of harmful impurities, scheme VI (Table 2).
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| 4. |
It is shown that scheme V (Table 2) has high schematic viscosity in a nonuniform velocity field, and therefore cannot be used
to calculate flows in chambers with complex geometry.
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| 5. |
Using the numerical modeling of the physical fields (air velocity and impurity concentration) in a ventilated volume proposed
here permits the determination either of the time to achieve the maximum permissible concentration with specified contamination-source
intensities and air flow rates or the air flow rate required in a specified ventilation time.
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S. M. Kirov Mining Institute, Academy of Sciences of the USSR, Kazan’ Branch, Apatity. Translated from Fiziko-Tekhnicheskie
Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 74–88, January–February, 1990. 相似文献
6.
Conclusions
| 1. |
The use of excavator-power-shovels with a scoop of active operation for mining coal-saturated regions makes it possible to
simplify the technology and eliminate the losses and impoverishment caused by drilling and blasting operations.
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| 2. |
A method of computation based on modelling of the trajectory of the excavator scoop can reliably evaluate indices characterizing
coal loss and impoverishment in the selective and selective-gross mining of seams by excavators with a scoop of active operation.
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| 3. |
The selective mining of coal seams with excavators equipped with a scoop of active operation is effective when the seams are
excavated in sub-benches and the dip angle of the hanging wall is within the range α=45–65° (EKG-5V0 and α+48–78° (EKG-12V).
Such excavation is effective in selective-gross mining when α>50° (EKG-5V, EKG-12V).
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Institute of Mining, Siberian Branch, Russian Academy of Sciences. Translated from Fizkiko-Tekhnicheskie Problemy Razrabotky
Poleznykh Iskopaemykh, No. 6, pp. 85–92, November–December, 1998. 相似文献
7.
| 1. |
A model of breakage mechanism and dust yield kinematics is suggested describing the fracturing of permafrost rocks in terms
of the theory of brittle breakage of materials.
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| 2. |
The mechanism of dust yield in bore hole drilling and other mining operations suggested in this paper will help introduce
efficient methods for dust suppression at subfreezing temperatures in operations involving breakage of perennially frozen
rocks.
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| 3. |
A further, more profound study of dust ejection velocity v2 will help develop a method for dust suppression at the site of its origination.
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Northern Institute of Mining, Yakutian Branch, Siberian Department, Academy of Sciences of the USSR, Yakutsk. Translated from
Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 54–58, September–October, 1988. 相似文献
8.
| 1. |
Cavity elimination technology by isolation and filling with low-strength materials has been used successfully in working mineral
resources by underground mines, including beds of complex structure.
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| 2. |
The technicoeconomic and social effectiveness of cavity elimination that preserves the surface of the earth and the environmental
setting in the area surrounding the mines and the utilization of production wastes and low-quality local mineral resources
endow these technologies with a conservation-oriented value and open new prospects for their use.
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| 3. |
Scientific and engineering principles of resource-saving cavity elimination technologies and years of practical experience
with them should be considered by designers of plans for development of new deposits in mining fields across the country.
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| 4. |
Tested methods of material quality improvement are recommended for large-scale introduction in mining and related industries:
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disintegrator processes of material grinding and activation;
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vibration equipment for sorting, triturating, and transporting granular and fluid mixtures; and
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electrochemical water treatment with membrane technologies.
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相似文献
9.
Conclusions
| 1. |
It was found experimentally that the natural mineral brucite has anomalously high sorption properties in relation to ions
of heavy metals in an aqueous medium.
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| 2. |
A comparative evaluation of the sorption properties of brucite and well-known natural zeolites demonstrates the clear technological
advantages of brucite.
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| 3. |
This article is intended to be the first of a series of reports on a new class of natural sorbents. Detailed and comprehensive
study of these materials will help clarify the main features of the mechanism of sorption on natural sorbents and significantly
broaden the range of practical application of brucite as an active sorbent in technologies developed for the purification
of natural and process water.
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Mining Institute, Siberian Branch of the Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 72–77, July–August, 1998. 相似文献
10.
Conclusions
| 1. |
For the example of sinusoidal pulses applied to the end of a pipe, we have shown that a pulse with the greatest amplitude
at fixed shock energy will drive the pipe furthest into the ground.
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| 2. |
Other conditions being equal, the greatest distance to which the pipe is driven in the ground is directly proportional to
the amplitude of the initial pulse applied to the end of the pipe.
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| 3. |
The residual strain (stress) in the pipe due to the presence of external friction increases with the length of the shock pulse.
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| 4. |
The damping of the shock-pulse amplitude is linear, regardless of the elastic properties of the ground, as long as individual
sections of the pipe slip relative to the ground. The damping coefficient is directly proportional to the frictional coefficient
of the pipe in the ground and does not depend on the shock-pulse configuration.
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| 5. |
Analysis shows that the distance to which the pipe is driven in the ground may be increased by a factor of more than 1.5,
at constant shock energy, by eliminating the intermediate mass from the model of the shock-pulse generator; in practice, the
intermediate mass corresponds to the housing of the shock machine rigidly connected to the anvil.
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Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 48–58, March–April, 1998. 相似文献
12.
Conclusions
| 1. |
We have shown that classical laws of elasticity and inelasticity reflect the variation in the reactive forces (the frictional
forces between rigid components of an element of the medium) in Newton's law of motion as a function of the growth in the
strain and the strain rate. Therefore, the defining relations do not include the second derivative of the displacement or
the strain with respect to the timet.
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| 2. |
Inequality of the loading forces and the reactive forces on the samples in the experiments leads to dynamic phenomena, corresponding
to uncontrollable additional contributions to the stress-strain and strain-time curves.
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| 3. |
With mild loading conditions of a thick-walled tube made of material that is incompressible and has a descending branch, abrupt
cumulative increase in the displacements, velocities, and accelerations is observed, even with proportional loading at low
rates.
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Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 34–49, September–October, 1998. 相似文献
13.
Conclusions
| 1. |
The possibility of tracking the trajectory of a pneumatic punch by recording oscillations of the ground excited by the shock
pulses has been experimentally confirmed.
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| 2. |
To determine the motion of a pneumatic punch in a horizontal plane, one receiver of seismoacoustic oscillations must be installed
at the point to which the punch is headed, with two others in symmetric positions to the left and right.
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It remains to thank V. N. Oparin for initial consultations and A. D. Kostylev and B. N. Smolyanitskii for practical assistance
in the work.
Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 117–121, July–August, 1998. 相似文献
14.
| 1. |
The analogy in the behavior of a rock mass and a granular medium is commonly used to build physical models of equivalent materials.
The analogy can be extended to mathematical models as well.
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| 2. |
An actual discontinuous velocity field can be described in terms of both an average smooth field (1.3) and kinematic tensors
(1.12). The tensor ɛ represents macrodeformations and rotations. The other tensors appear as additional kinematic variables
(microdeformations and rotations). The tensor ɛΠ describes deformation of the cement; ɛt, ɛτ describe deformation of particles; ɛR describes the relative slippage of particles. In a comparison with one-dimensional construct (1.1) the actual velocity field
(x1, x2) corresponds to the function F(x); the field
(x1, x2) to f(x); the tensor ɛ to the derivative f'(x); and the remaining tensors to the “local derivative” g'(x).
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| 3. |
Deformations and rotations at the microlevel are connected with macrodeformations and rotations by compatibility conditions
(1.14), (1.20), (1.21).
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Institute of Mining, Siberian Department, Academy of Sciences of the USSR, Novosibirsk. Translated from Fiziko-Tekhnicheskie
Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 14–21, July–August, 1990. 相似文献
15.
During the 1990s, passive treatment technology was introduced to the United Kingdom (UK). Early hesitancy on the part of regulators
and practitioners was rapidly overcome, at least for net-alkaline mine waters, so that passive treatment is now the technology
of choice for the long-term remediation of such discharges, wherever land availability is not unduly limiting. Six types of
passive systems are now being used in the UK for mine water treatment:
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♦ aerobic, surface flow wetlands (reed-beds);
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♦ anaerobic, compost wetlands with significant surface flow;
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♦ mixed compost/limestone systems, with predominatly subsurface flow (so-calledReducing andAlkalinityProducingSystems (RAPS));
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♦ subsurface reactive barriers to treat acidic, metalliferous ground waters;
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♦ closed-system limestone dissolution systems for zinc removal from alkaline waters;
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♦ roughing filters for treating ferruginous mine waters where land availability is limited.
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Each of these technologies is appropriate for a different kind of mine water, or for specific hydraulic circumstances. The
degree to which each type of system can be considered “proven technology” corresponds to the order in which they are listed
above. Many of these passive systems have become foci for detailed scientific research, as part of a $1.5M European Commission
project running from 2000 to 2003. 相似文献
16.
Conclusions
| 1. |
It is proposed that the energy content of dynamic scoops be evaluated on the basis of the quantity of relative power —the
ratio of the total power of the drive of the percussive teeth to the capacity of the scoop es. It is also proposed that the ratio es/zf be used as an index of the efficiency of such scoops. Here, zf is the require degree of fragmentation of the rock. Based on this criterion, a scoop with a capacity of 12 m3 is found to have the best energy characteristics.
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| 2. |
The proposed design method makes it possible to predict the energy content of the process of excavating rock by means of excavators
equipped with a dynamic scoop.
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| 3. |
Given the current level of development of pneumatic hammers, from the standpoint of total unit energy expenditures the excavation
of rock by excavators and mechanical shovels with dynamic scoops is expedient for rocks having a strength of 70–85 MPa and
classified as II or III with respect to block structure.
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Mining Institute, Siberian Branch of the Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 66–72, May–June, 1998. 相似文献
17.
Conclusions The following characteristics of self-transportation have been established.
| 1. |
If the frictional force F does not exceed the recoil force within a single oscillation period T of the vibrational device,
the phase length of forward motion in steady self-transportation is always half the period; it only becomes less than half
the period when the relationship between these forces reverses. In the vicinity of the point where this relationship reverses,
the rate of self-transportation of the device is a maximum.
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| 2. |
If the preimpact momentum of a device operating in vibroshock conditions is less than the critical value i=FT/4, self-transportation
is always in the opposite direction to the shocks.
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| 3. |
The greatest rate of self-transportation that is theoretically possible is equal to the critical momentum i of the system
divided by the mass of the base element.
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| 4. |
The rate of self-transportation depends on the form of the momentum diagram of the resultant of the internal active forces
acting on the base mass. The character of the dependence and the relevant criteria are analogous to those established in evaluating
the ability of the form factor to reduce the vibration and the necessary input force for shock machines.
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These results offer the possibility of further analysis of self-transportation, taking the characteristics of the specific
generator of the internal active forces into account.
Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 59–65, November–October, 1997. 相似文献
18.
Conclusions
| 1. |
Inrushes and caving of the roof in the face region can be prevented by creating the conditions necessary for independent shifting
of the ceiling of ShchRP-type supports under the influence of pressure of the caved rocks. Such conditions are created by
freely joining the ceiling to the base and suitably choosing the parameters of the support.
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| 2. |
Choosing efficient parameters for a self-advancing support and the stope makes it possible to keep the surface of the stope
at an angle close to the angle of repose. If the ceiling and base are freely joined one to another, choosing such parameters
allows the efficinet excavation of coal in the supercritical state.
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| 3. |
For ShchRP supports which have a freely joined ceiling and base and are used to mine thick steep seams, “kick” movement of
the support as a whole is preferable to separate movement of the ceiling and base, since separate movement may prove difficult
under the given conditions.
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Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy
Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 74–84, November–December, 1998. 相似文献
19.
| 1. |
With low-temperature plasma it is possible to create facings in soft rocks covering the entire working perimeter in a short
period of time.
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| 2. |
Field tests of facing models show them to have a sufficient carrying capacity and resistance to dynamic as well as static
loads.
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| 3. |
Laboratory tests of specimens from thermally reinforced clay rocks determined the dynamics of the variation of their strenth
characteristics as a function of the speed of loading.
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Military Engineering Academy, Togliatti. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No.
2, pp. 74–78, March–April, 1989. 相似文献
20.
| 1. |
A new model is suggested with simple techniques representing the dynamic behavior of an assembled support system at intersections
of horizontal mine workings. Plastic behavior of the material at the conjugation points of structural elements is taken into
account.
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| 2. |
Equations systems are formulated to calculate the behavior of a support system sustaining static and dynamic rock pressures.
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| 3. |
In case of a dynamic impact upon the support system at a conjugation, the greatest strength is attained when the rigidity
of the external medium is higher than that of the medium filling the space between the support systems of the individual workings.
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| 4. |
When a plane wave acts upon the support system at the conjugation, the internal support system removed from the wavefront
at the initial time is especially susceptible to breakdown.
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| 5. |
Support systems interact not only in terms of vibration amplitude but also vibration frequency and form. The influence of
internal support systems upon the external support system is particularly strong.
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Institute of Mathematics and Mechanics, Academy of Sciences of the Kazak SSSR, Alma-Ata. Translated from Fiziko-Tekhnicheskie
Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 6–12, May–June, 1990. 相似文献
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