共查询到20条相似文献，搜索用时 109 毫秒
1.
Conclusions The prospect of switch-over of the industry to processing lean materials raises the problem of beneficiation of finely disperse
placers of noble metals, the profitability of realization of which lies in raising the efficiency of separation processes
by reducing frictional forces in the course of implementation of the technological processes and by employing modern technologies
for beneficiation. The engineering—technological solutions worked out are distinguished by ecological safety during implementation
of the beneficiation processes.
The proposed schemes of beneficiation and primary processing of finely disperse minerals may be used:
| – |
- for enhancing profitability of utilization of currently exploited placers of noble metals;
|
| – |
- for reviewing economic effectiveness of technologically unprofitable coastal-marine placers in which finely disperse fractions
of useful components are prevalent;
|
| – |
- for reprocessing of rejects of previously processed placers;
|
| – |
- for recovery of platinoids and gold from bedrocks.
|
Scientific Research Center, Far Eastern Branch, Russian Academy of Sciences, Petropavlovsk-Kamchatskii. Translated from Fiziko-Tekhnicheskie
Problemy Razrabotki Poleznykh Iskopaemykh, Vol. 34, No. 3, pp. 108–113, May–June, 1998. 相似文献
2.
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;
|
| – |
o consolidation of rocks due to the ground-water pressure drop;
|
| – |
o water-and-rock material inrushes into mine workings caused by deformations of the undermined rock mass;
|
| – |
o geodynamical processes due to the changes in ground water regime;
|
| – |
o artificial hydrofracturing in rocks;
|
| – |
o transformations of clay linings under the tailing ponds and other technical water basins
|
相似文献
3.
| 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.
|
| 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.
|
| 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.
|
| 4. |
Tested methods of material quality improvement are recommended for large-scale introduction in mining and related industries:
| – |
disintegrator processes of material grinding and activation;
|
| – |
vibration equipment for sorting, triturating, and transporting granular and fluid mixtures; and
|
| – |
electrochemical water treatment with membrane technologies.
|
相似文献
4.
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:
| – |
♦ aerobic, surface flow wetlands (reed-beds);
|
| – |
♦ anaerobic, compost wetlands with significant surface flow;
|
| – |
♦ mixed compost/limestone systems, with predominatly subsurface flow (so-calledReducing andAlkalinityProducingSystems (RAPS));
|
| – |
♦ subsurface reactive barriers to treat acidic, metalliferous ground waters;
|
| – |
♦ closed-system limestone dissolution systems for zinc removal from alkaline waters;
|
| – |
♦ roughing filters for treating ferruginous mine waters where land availability is limited.
|
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
5.
| 1. |
Electromechanical regime observations in North Ural bauxite deposits can be used to evaluate the transcritical strain in rocks,
such as loosening or pillar breakage under long-term loads.
|
| 2. |
In conditions where no discontinuities of rocks in the peripheral zone of workings are observed, electrometric technology
can evaluate moisture content variations.
|
| 3. |
With the existing technology, it is impossible to estimte elastic strain by electrometric measurements in North Ural bauxite
deposits.
|
Ural Scientific-Research Institute of Copper Production, Sverdlovsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki
Poleznykh Iskopaemykh, No. 6, pp. 92–98, November–December, 1989. 相似文献
7.
| 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.
|
| 2. |
Statistical characteristics of variation series were obtained.
|
| 3. |
Maps of isolines representing the “principal relief forms” have been compiled, which describe the regularities of distribution
of the technical parameters.
|
| 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.
|
Moscow Institute of Mining. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Polyznykh Iskopaemykh, No. 6, pp. 84–91,
November–December, 1990. 相似文献
8.
Conclusions
| 1. |
Nitrous acid has a catalytic effect on the sulfuric-acid decomposition of galena. With oxygen at atmospheric pressure, the
presence of even small quantities of HNO2 in the solution (0.01 M) at room temperature increases the degree of oxidation of lead sulfide twofold.
|
| 2. |
The solid products of the oxidation of PbS (PbSO4 and S) form a dense film on the surface of the reacting particles, which leads to a decrease in the reaction rate. The kinetic
curves are parabolic in form.
|
| 3. |
The rate of oxidation of galena depends on the initial concentration of sulfuric acid in the solution. The order of the reaction
with respect to H2SO4 is close to unity (0.99).
|
| 4. |
The apparent activation energy of the process is 12.8 kJ/mole.
|
| 5. |
A change in the rate of mixing of the reaction mixture has almost no effect on the degree of decomposition of galena.
|
The process of the sulfuric-acid oxidation of galena, catalyzed by nitrous acid, occurs in the intradiffusional regime and
can be satisfactorily described by the Ginstling—Braunstein equation. This, equation reflects the fact that the reaction rate
depends on the completeness of the reaction due to the changing thickness of the layer of solid product that is formed. The
dependence is described by the equation for different temperatures and different concentrations of sulfuric acid in the solution:
{fx331-1} where α is the fraction of galena oxidized to the sulfate; CH 2SO 4is the initial concentration of sulfuric acid, moles/liter; T is temperature, K; τ is time, sec.
United Institute of Geology, Geophysics, and Mineralogy of the Siberian Branch of the Russian Academy of Sciences. Novosibirsk.
Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 56–64, July–August. 1998. 相似文献
9.
| 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.
|
| 2. |
Field tests of facing models show them to have a sufficient carrying capacity and resistance to dynamic as well as static
loads.
|
| 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.
|
Military Engineering Academy, Togliatti. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No.
2, pp. 74–78, March–April, 1989. 相似文献
10.
| 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.
|
| 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.
|
| 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);
|
| b) |
for discharge emissions of harmful impurities, scheme VI (Table 2).
|
|
| 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.
|
| 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.
|
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
11.
| 1. |
To predict the creep of rock, it is expedient to use the method of analogies, which was developed specifically for polymeric
materials, especially the principles of stress— time and baro-time analogies.
|
| 2. |
Use of the method of analogies makes it possible to predict the creep of rock existing in both a uniaxial and three-dimensional
stressed state. In this case, the time interval of the investigations is expanded by 1–2 orders of magnitude as a function
of the conditions under which the rock is tested for creep.
|
General of the Army A. N. Komarovskii Higher Military Civil Engineering School, Leningrad. Translated from Fiziko-Tekhnicheskie
Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 40–45, March–April, 1990. 相似文献
12.
| 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.
|
| 2. |
Equations systems are formulated to calculate the behavior of a support system sustaining static and dynamic rock pressures.
|
| 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.
|
| 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.
|
| 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.
|
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
13.
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.
|
| 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.
|
| 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.
|
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
14.
| 1. |
In a conveyer-hopper system of underground coal mine transport a load stream can be represented by a vector Γ6 comprised of six linearly independent parameters:
, qΠ, σΠ, qmax, σK and tΠ.
|
| 2. |
An analytic model has been developed describing the transformation of load streams, which allows defining the parameters of
the vector Γ6 in an arbitrary cross-section of a conveyer-hopper system. It helps improve the accuracy of process evaluations for under-ground
transport system.
|
| 3. |
At an arbitrary cross-section of the conveyer-hopper system, load streams can be described by a Markov step process. This
provides a uniform framework for study of load stream transformations.
|
| 4. |
The length of periods of load stream arrival and stream absence conform to an exponential distribution. The intensity of transformed
load streams follows a normal distribution in a portion of the arrival period.
|
| 5. |
A good convergence has been established between the results of calculations of the maximum composite load stream and normative
data obtained from a computer simulation study.
|
Donetsk Coal Institute, Donetsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp.
71–77, November–December, 1989. 相似文献
15.
| 1. |
The distribution of lumps by mass is a complementary structural-statistical lumpiness characteristic that makes it possible
to ascertain more clearly certain laws governing the process of fragment formation as compared with the distribution of lumps
by size.
|
| 2. |
A Weibull-type equation provides good approximation of unimodal curves of mass distribution for the different conditions considered
for the multiple fracture of rigid bodies.
|
| 3. |
There are characteristic points about which values of the distribution-shape parameter are grouped: the shape parameter is
close to 1/3 for the impact failure of lumps and the crushing of specimens, and to 1/2 for the case of explosive crushing.
|
| 4. |
An increasing in the end surcharge of tubular rock specimens failed by blasting leads to a reduction in the shape parameter
for the fine fractions and to diminution of the bimodality effect.
|
| 5. |
Use of the operation of the additional opening of blast-induced cracks in weakened lumps of semimetallic ore is reflected
in geometrically similar transformations of the distribution curves in the direction of a reduction in lump mass.
|
| 6. |
As applies to the blast-induced failure of brittle plates, a functional relationship between the mass of the fragments and
the reduced distance to the blast center is obtained by statistical averaging; for small values of the argument, the latter
is approximated by the fourth power of the reduced distance.
|
I. I. Polzunov Branch of the Altai Polytechnic Institute, Biisk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki
Poleznykh Iskopaemykh, No. 1, pp. 34–38, January–February, 1989. 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.
|
| 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.
|
| 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.
|
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.
| 1. |
It is recommended to drive a slot heading with formation of lead faces in the near-wall areas followed by the breaking of
the pillar remaining in the middle part of the working. The lead face should be 10–20 mm wide. The pillar exposure degree
should be 1.15–1.55.
|
| 2. |
The performance of the slot formation process Π∼A3/2n, where A is a unit stroke energy and n is the stroke frequency. Therefore, it is more efficient to increase the energy of
a single stroke rather than the stroke frequency.
|
| 3. |
The optimum criterion for the parameters of the impact system with the electro-mechanical drive is the maximum value of the
ratio A3/2n.
|
Polytechnical Institute, Alma-Ata. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4,
pp. 69–72, July–August, 1991. 相似文献
18.
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.
|
| 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.
|
| 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.
|
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
19.
| 1. |
By analyzing the formation of brines in underground leaching chambers, it is shown that the general criterial dependence representing
this process includes the criteria Pz, Ku, and the geometrical simplex D/h.
|
| 2. |
The authors determine the conditions of similarity for modeling the processes of brine formation in underground leaching chambers
by means of specimens of core material.
|
相似文献
20.
| 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.
|
| 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.
|
| 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.
|
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
|
|
