Sensitivity analysis of the dynamic response of both the designed and the actual models of a slewing superstructure with two masts to the variation of the counterweight mass and the degree of accuracy of the
approximation polynomials of the digging resistance was conducted in the paper. Spatial reduced dynamic models of the bucket wheel excavator SchRs 1600 were used as a basis for the presented investigations.
Based on the comparative analysis of the calculation results, the following conclusions were drawn: (a) mass of the counterweight has a significantly higher influence on the maximum intensities of accelerations
of the referent points than on the spectrum of natural frequencies, (b) the accuracy of approximations of the digging resistance and the maximum values of accelerations differ by an order of magnitude, for
the approximation trigonometric polynomial of the same number of harmonics.
Mining activity influence on the environment belongs to the most negative industrial influences. Land subsidence can be a consequence of many geotectonic processes as well as due to anthropogenic
interference with rock massif in part or whole landscape. Mine subsidence on the surface can be a result of many deep underground mining activities. The presented study offers the theory to the specific case of
the deformation vectors solution in a case of disruption of the data homogeneity of the geodetic network structure in the monitoring station during periodical measurements in mine subsidence.
The theory of the specific solution of the deformation vector was developed for the mine subsidence at the Košice-Bankov abandoned magnesite mine near the city of Košice in east Slovakia. The outputs
from the deformation survey were implemented into Geographic Information System (GIS) applications to a process of gradual reclamation of whole mining landscape around the magnesite mine. After completion
of the mining operations and liquidation of the mine company it was necessary to determine the exact edges of the Košice-Bankov mine subsidence with the zones of residual ground motion in order to
implement a comprehensive reclamation of the devastated mining landscape. Requirement of knowledge about stability of the former mine subsidence was necessary for starting the reclamation works. Outputs
from the presented specific solutions of the deformation vectors confirmed the multi-year stability of the mine subsidence in the area of interest. Some numerical and graphical results from the deformation
vectors survey in the Košice-Bankov abandoned magnesite mine are presented. The obtained results were
transformed into GIS for the needs of the self-government of the city of Košice to the implementation of
the reclamation works in the Košice-Bankov mining area.
The geodetic measurements optimization problem has played a crucial role in the mining areas affected by continuous ground movement. Such movements are most frequently measured with the
classical geodetic methods such as levelling, tachymetry or GNSS (Global Navigation Satellite System).
The measuring techniques are selected with respect to the dynamics of the studied phenomena, surface hazard degree, as well as the financial potential of the mining company. Land surface changes caused by
underground exploitation are observed with some delay because of the mining and geological conditions of the deposit surroundings. This delay may be considerable in the case of salt deposits extraction due
to slow convergence process, which implies ground subsidence maximum up to a few centimeters per year. Measuring of such displacements requires high precision instruments and methods. In the case of
intensely developed urban areas, a high density benchmark network has to be provided. Therefore, the
best solution supporting the monitoring of vertical ground displacements in the areas located above the
salt deposits seems to be the Sentinel 1-A radar imaging satellite system.
The main goal of the investigation was to verify if imaging radar from the Sentinel 1 mission could
be applied to monitor of slow ground vertical movement above word heritage Wieliczka salt mine. The
outcome of the analysis, which was based on DInSAR (Differential SAR Interferometry). technology, is
the surface distribution of annual subsidence in the period of 2015-2016. The comparison of the results
with levelling confirmed the high accuracy of satellite observations. What is significant, the studies
allowed to identify areas with the greatest dynamics of vertical ground movements, also in the regions
where classical surveying was not conducted. The investigation proved that with the use of Sentinel-1
images sub centimeters slow vertical movements could be obtained.
The main objective of this study was to assess the environmental impact of the subsurface geological
structure in Nam Son landfill by hydrogeophysical method. The Electrical Resistivity Tomography (ERT), Self-
-Potential (SP) and Very Low Frequency (VLF) method was used for geological structure investigation. Three
profiles (total 900 m long) of two-dimensional ERT, VLF density sections and 180 SP data points scattered
within the study area near the disposal site were implemented. Surface water and groundwater samples were
collected from 10 sites in the area for hydrochemical analysis. Interpretations of geophysical data show a low
resistivity zone (<15 Ω m), which appears to be a fully saturated zone with leachate from an open dumpsite.
There is a good correlation between the geophysical investigations and the results of hydrochemical analysis.
Lower Carboniferous limestone has been extracted in the “Czatkowice” open-pit hill-slope quarry in
southern Poland since 1947, for the needs of metallurgical and building industries, as well as farming. We
can distinguish two aquifers in the Czatkowice area: the Quaternary porous aquifer and the Carboniferous
fissure-porous one. Two vertical zones representing different hydrodynamic characteristics can be indentified
in the Carboniferous formations. One is a weathering zone and the other one the zone of fissures
and interbedding planes. Groundwater inflows into the quarry workings have been observed at the lowest
mining level (+315 m above the sea level (asl)) for over 30 years. This study concerns two hypotheses of
the sources of such inflows originating either from (a) the aeration zone or from (b) the saturation zone.
Inflows into the quarry combine into one stream flowing gravitationally to the doline under the pile in the
western part of the quarry. This situation does not cause a dewatering need. Extending eastward mining
and lowering of the exploitation level lead to increased inflows.
Lower Carboniferous limestone has been extracted in the “Czatkowice” open-pit hill-slope quarry in
southern Poland since 1947, for the needs of metallurgical and building industries, as well as farming. We
can distinguish two aquifers in the Czatkowice area: the Quaternary porous aquifer and the Carboniferous
fissure-porous one. Two vertical zones representing different hydrodynamic characteristics can be indentified
in the Carboniferous formations. One is a weathering zone and the other one the zone of fissures
and interbedding planes. Groundwater inflows into the quarry workings have been observed at the lowest
mining level (+315 m above the sea level (asl)) for over 30 years. This study concerns two hypotheses of
the sources of such inflows originating either from (a) the aeration zone or from (b) the saturation zone.
Inflows into the quarry combine into one stream flowing gravitationally to the doline under the pile in the
western part of the quarry. This situation does not cause a dewatering need. Extending eastward mining
and lowering of the exploitation level lead to increased inflows.
The hereby paper is devoted to the analysis of operational properties of vibratory conveyors, which principle of operations is based on the Frahm’s dynamic elimination effect (Den Hartog, 1971). These
conveyors, according to the data given by their producers have several advantages, among others, higher vibrations amplitudes at the same drive and exceptionally low dynamic forces transmitted to the foundation.
The simulation model of such conveyor loaded with a feed was created in this work and investigations of the transport efficiency and forces transmitted to the foundation at stationary states as well as at start
up and coasting periods were performed. Analytical tests of vibrations during unsteady motion periods were also performed and the method of determining maximum amplitudes of conveyors in the transient
resonance during coasting was proposed. The research results indicate the possibility of a wide application of this type of machines in loose materials handling in various industry branches.
The paper presents a new method for measuring the strain and load of wire ropes guide using fiber
optic sensors with Bragg gratings. Its principle consists in simultaneous fiber optic measurement of
longitudinal strain of the rope and transverse strain of the bolt fixing the rope. The tensometric force
transducers which have been used so far were only able to determine the load in the head securing the
rope through an indirect measurement using a special strain insert. They required calibration, compensation
of temperature changes, as well as periodic checking and calibration. The head fastening the rope
required significant design changes. Measurement based on fiber optic sensors does not have these
drawbacks and is characterized by a much higher accuracy and safety of measurements, because the
working medium is light. The fastening head does not change. The measurement of the rope load may be
based on the change of strain value or indirectly by means of measuring the deflection of the bolt fixing
the rope holder. The proposed solution consists in placing the optical fiber with Bragg grating inside the
bolt. It enables continuous measurements with a frequency of 2 kHz. A special test bench was built at
the Research and Supervisory Centre of Underground Mining. Testing on guide ropes was carried out in
a mining hoist in the Piast mine.
The presented paper describes the results of an experiment determining the instantaneous values of
velocity vector components of the air stream at selected spots of the boundary layer formed at the sidewalls
of the mine heading in the ŁP type steel arch support. The experiment was carried out in a mine heading
in an active hard coal mine. A 3-axis thermoanemometric probe was used to obtain three-dimensional
distributions of the velocity and turbulent values, such as turbulence intensity and turbulent kinetic energy
of the flowing ventilation air stream. The analysis of the measurement results was aided by a numerical
solution of the discussed case of flow.
The research results presented in this paper provide a basis for extensive studies of the description of
velocity distribution and other turbulent quantities within the near-sidewall structures of a mine heading.
The objective of these tasks is to improve the accuracy and reliability of numerical calculations relating
to air flow in mine headings.
The evaluation accuracies of rock mass structures based on the ratings of the Rock Quality Designation
(RQD) and discontinuity spacing (S) in the Rock Mass Rating (RMR) system are very limited
due to the inherent restrictions of RQD and S. This study presents an improvement that replaces these
two parameters with the modified blockiness index (Bz) in the RMR system. Before proceeding with this
replacement, it is necessary for theoretical model building to make an assumption that the discontinuity
network contains three sets of mutually orthogonal disc-shaped discontinuities with the same diameter
and spacing of discontinuities. Then, a total of 35 types of theoretical DFN (Discrete Fracture Network)
models possessing the different structures were built based on the International Society for Rock Mechanics
(ISRM) discontinuity classification (ISRM, 1978). In addition, the RQD values of each model
were measured by setting the scanlines in the models, and the Bz values were computed following the
modified blockiness evaluation method. Correlations between the three indices (i.e., Bz, RQD and S) were
explored, and the reliability of the substitution was subsequently verified. Finally, RMR systems based
on the proposed method and the standard approach were applied to real cases, and comparisons between
the two methods were performed. This study reveals that RQD is well correlated with S but is difficult
to relate to the discontinuity diameter (D), and Bz has a good correlation with RQD/S. Additionally, the
ratings of RQD and S are always far from the actual rock mass structure, and the Bz ratings are found to
give better characterizations of rock mass structures. This substitution in the RMR system was found to
be acceptable and practical.
In technology of coal fines beneficiation in Poland mainly fines jigging processes are in use. In case
of steam coal fines beneficiation it is till 80% of the whole amount of produced assortments, while in
case of coking coal fines it is 100%.
The necessary condition of not homogenous feed separation which is directed to beneficiation process
in pulsating water stream is a sufficient liberation of particles. The stratification of particles in working
bed causes that particles of certain size, density and shape gather in individual layers in working bed of
jig. The introduction of sufficient amount of additional water determines appropriate liberation of particles
group, which generates partition into concentrate and tailings.
The paper presents the results of sampling of industrial jig used for the beneficiation of coal fines
by three various settings of additional amount of water under sieve which is directed to jigging. These
amounts were equal to 35, 50 and 70 [m3/h]. Collected samples of separation products were then sieved
into narrow particle size fractions and divided into density fractions. In such narrow size-density fractions
the coordinates of partition curves were calculated for tailings of hard coal fines, which were subsequently
approximated by means of Weibull distribution function. The separation precision measured by separation
density, probable error and imperfection were determined on the basis of obtained model separation
curves. The evaluation of separation effects was performed for a wide particle size fraction: feed directed
to jigging process and narrow particle size fractions. The analysis of separation results in size-density
fractions allowed to determine the influence of particle size change on the value of probable error. The
results of separation precision in size-density fractions were compared with effects of separation of wide
particle fraction, i.e. feed directed to jigging process.
To solve the problem of large deformation soft rock roadway with complicated stress condition in Baluba copper mine, the characteristics of roadway deformation and failure modes are analyzed deeply on
the basis of geological survey. Combined with the theoretical analysis and numerical simulation, the new reinforcement technology with floor mudsill and grouting anchor cable is proposed. Moreover, the three
dimension numerical simulation model is established by the software FLAC-3D, the support parameter
is optimized by it. The results show that the optical array pitch of the U-steel shelf arch is 0.8 m, and the
optical array pitch of the grouting anchor cable is 2.4 m. At last, the field experiments are done all over
the soft rock roadway. Engineering practice shows that the deformation of soft rock roadway in Baluba
copper mine is effectively controlled by adopting the new reinforcement technology, which can provide
certain references for similar engineering.
The article concerns investigations over benefits of application of HRC devices into sulphide copper
ore processing plant. High pressure comminution appears to be very effective technology in hard ore
processing circuits, especially in terms of energy consumption. This can be particularly observed in
downstream grinding and beneficiation operations. A series of pilot-scale crushing tests in HRC roller
press for various levels of operating pressure, were performed. HRC crushing effectiveness along with
downstream grinding process course for each crushing product were also under analysis. The investigations
were supplemented by analysis of flotation process effectiveness and impact of the process of
high-pressure comminution on environment (dust emission). The results of investigation show that operating
pressure level influences the obtained comminution results (comminution degree, yield of finest
particle size fractions). The grinding effectiveness, measured through production of the finest particle size
fractions was significantly influenced by the operating pressure. The results show that higher values of
operating pressure (4.0 and 4.5 N/mm2) are not as efficient within this scope as the pressure 3.5 N/mm2.
Dust emission is also correlated with the operating pressure value.
The article presents the results of tests on SHC-40 hydraulic props equipped with two types of valve blocks: standard (with spring steel cylinder) and BZG-2FS (with gas spring). The research was conducted
using impact mass of 4,000 kg and with extreme dynamic load of free fall impact mass of 20,000 kg released from different heights h. The dynamic tests involved a camera with the speed of image capture
up to 1,200 frames/sec, which made it possible to register the stream of liquid at the dynamic load and to determine the valve opening time.
The study conducted on SHC-40 NHR10 props equipped with two types of valve blocks: a standard and the BZG-2FS fast acting relief, showed that the prop with the BZG-2FS block is more suitable and more effective in the case of areas with high risk of mining tremors and rapid stress relief of a seam.
Research methodology developed in the Central Mining Institute combines digital recording technique of pressure in a prop and fast registration of the images, and allows to acquire more accurate analysis of
dynamic phenomena in the prop during testing.
Gas emissions from underground sites to the atmosphere depend on many factors. Pressure drops are
considered to be the most important. However, emissions can also be observed during the initial phase
of the pressure rise, following a previous drop in pressure. On the other hand, gas emissions may not be
detected when the pressure drops, especially when a previous pressure rise has taken place.
The aim of the research was to determine the role of variations in baric tendency on airflow rate and
its direction.
To solve this problem a numerical model was built utilizing the Ansys Fluent software package.
Subsequently, three scenarios of baric tendency variations were tested: a) rise – drop, b) drop – drop,
c) drop – rise.
The results showed inert behavior of gases. Under scenario (c), 1 hour after the change in tendency
gases still were flowing out to the atmosphere.
Considering scenario (a), it was proved that even during a pressure drop gas emissions do not take
place, which can be crucial for further determination of the gas hazard at the surface or for assessment of
the rate of gas emissions from a particular gas emitter.
Scenario (b) merely gave an overview of the process and was mainly used for validation purposes.
It gave a maximal CO2 concentration of 2.18%vol (comparable to measurements) and a CO2 mass flow
rate 0.15kg/s. Taking into account greenhouse gas emissions this amounted to 514 kg CO2/h.
In order to optimize the stope structure parameters in broken rock conditions, a novel method for the
optimization of stope structure parameters is described. The method is based on the field investigation,
laboratory tests and numerical simulation. The grey relational analysis (GRA) is applied to the optimization
of the stope structure parameters in broken rock conditions with multiple performance characteristics.
The influencing factors include stope height, pillar diameter, pillar spacing and pillar array pitch, the
performance characteristics include maximum tensile strength, maximum compressive strength and ore
recovery rate. The setting of influencing factors is accomplished using the four factors four levels Taguchi
experiment design method, and 16 experiments are done by numerical simulation. Analysis of the grey
relational grade indicates the first effect value of 0.219 is the pillar array pitch. In addition, the optimal
stope structure parameters are as follows: the height of the stope is 3.5 m, the pillar diameter is 3.5 m, the
pillar spacing is 3 m and the pillar array pitch is 5 m. In-situ measurement shows that all of the pillars can
basically remain stable, ore recovery rate can be ensured to be more than 82%. This study indicates that
the GRA method can efficiently applied to the optimization of stope structure parameters.
It is meaningful to study the issues of CO migration and its concentration distribution in a blind gallery to provide a basis for CO monitoring and calculation of fume-drainage time, which is of a great
significance to prevent fume-poisoning accidents and improve efficiency of an excavation cycle. Based on a theoretical analysis of a differential change of CO mass concentration and the CO dispersion model
in a fixed site, this paper presents several blasting fume monitoring test experiments, carried out with the
test location to the head LP in arrange of 40-140 m. Studies have been done by arranging multiple sensors
in the arch cross-section of the blind gallery, located at the Guilaizhuang Gold Mine, Shandong Province,
China. The findings indicate that CO concentrations in the axial directions are quadratic functions with
the Y and Z coordinate values of the cross-section of the blind gallery in an ascending stage of CO time-
-concentration curve, with the maximum CO concentrations in Y = 150 cm and Z = 150 cm. Also, the
gradients of CO concentration in the gallery are symmetrical with the Y = 150 cm and Z = 150 cm. In the
descending stage of CO time-concentration curve, gradients of CO concentration decrease in lateral sides
and increase in the middle, then gradually decrease at last. The rules of CO concentration distribution in the
cross-section are that airflow triggers the turbulent change of the CO distribution volume concentration and
make the CO volume concentration even gradually in the fixed position of the gallery. Moreover, the CO
volume concentrations decrease gradually, as well as volume concentration gradients in the cross-section.
The uniformity coefficients of CO concentration with duct airflow velocities of 12.5 m/s, 17.7 m/s and
23.2 m/s reach near 0.9 at 100-140 m from the heading to the monitoring spot. The theoretical model of
a one-dimensional migration law of CO basically coincides with the negative exponential decay, which
is verified via fitting. The average effective turbulent diffusion coefficient of CO in the blind gallery is
approximate to 0.108 m2/s. There are strong linear relationships between CO initial concentration, CO
peak concentrations and mass of explosive agent, which indicates that the CO initial concentration and
the CO peak concentration can be predicted, based on the given range of the charging mass. The above
findings can provide reliable references to the selection, installation of CO sensors and prediction of the
fume-drainage time after blasting.