The Required Amount of Mine Air Passing through the Emergency Passage into the Mine

This descriptive study was conducted to compare the job demands, job control, social support and mental health status of thermal power plant and underground coal mine workers. 158 workers in thermal power plant and 162 workers in underground coal mine participated in the study. The results unearthed that thermal power plant workers had 2.3 times better mental health (p < 0.001 OR = 2.3 CI = 1.50-3.74) and 3.0 times lower job demands (p < 0.001 OR = 3.0 CI = 1.91-4.92) than coal mine workers. In the study, it was determined that mental health was positively affected as job control and social support increased in both thermal power plant and underground mine workers (p < 0.05); there was no significant relationship between job demands and mental health (p > 0.05). These results indicate that underground mine workers are at higher risk in terms of mental health and job demands than thermal power plant workers.

Human-centered Development of Underground work Spaces

The ventilation networks are associated with the set of underground mining works used for the extraction of useful mineral substances. Over time, the ventilation networks involve a change in the structure due to either the expansion or restriction of the mining works structure. For the establishment of air flows at the level of each active mining work, specialized programs are used at international level. These programs allow the modelling and solving of complex ventilation networks. The most advanced specialized programs are those from the VENTSIM range. The paper presents the updating of the ventilation network related to Livezeni mine, with the help of the VENTSIM program.

There are many places in the different countries of the world where working in the underground mines have been done below surface structures such as railway lines, roads, buildings, villages/residential colonies, pipelines, etc. The workings are generally old, abandoned and presently unapproachable. In some places, important delicate surface structures are installed above a portion of old abandoned underground workings. Safety of these important surface structures above old underground mine workings is a serious concern in many countries all over the world. Many times, it is difficult to move or divert these surface structures due to a number of reasons including technical problems, the involvement of huge expenditures and socio-economic issues. There is a need to assess the stability of these places and the procedure to stabilise the places if found unstable to make the structures safe. Hence, there is a need of proper stability assessment of the ground below these surface structures. The railway line is one of such important structures, where stability should be ensured for the safety of the passengers. In India, many underground workings are present below railway lines. Most of the workings are old and unapproachable and their stability status is in doubt. Dismantling or diverting of the important railway lines is a high-level policy matter and involves huge time and money besides complicated socio-political issues like the rehabilitation of the affected people. But the safety of the commuters using railways passing over the coal-bearing areas having mining activities cannot be compromised. Therefore, it is highly preferable to take protective measures instead of dismantling and diversion of lines, wherever possible. It is necessary to establish the position and dimension of the inaccessible underground workings below these types of important surface structures and carry out its stability analysis to take appropriate protective measures for the safety of the structures and commuters. This paper highlights the delineation procedure of the unapproachable underground roadways below surface structures with special reference to railway lines and its stability evaluation with case studies. Appropriate protective measures have also been suggested which are proved to be effective and validated the results of the study.

The purpose of the study is to compare and adjust the results of stability forecast for Irokinda gold deposit underground mine workings using various estimation methods of rock mass state based on the analysis of structural parameters only, multiparameter classification of structural parameters and engineering-geological indicators according to Z. Bieniawski as well as mass fracturing distribution. Engineering and geological conditions of deposit deep horizons have been estimated using the data obtained under geomechanical description of the core when drilling exploratory and hydrogeological boreholes and description of the walls of underground mine workings. All these made it possible to estimate the rock mass fragmentation degree, which affects the stability of underground mine workings. A full range of physical, mechanical and deformation property definition was performed using rock samples taken from the core of exploratory boreholes and mine workings. A total of 184 samples have been taken and analyzed during the field season with distinguishing of 10 rock varieties characterized by different strength and stability degree. The comparative analysis conducted on the example of the Irokinda field implies the need of the integrated use of these methods, which will enable increasing of result reliability and most accurate determination of the stability class of the rock mass for its further mining. The results obtained by various methods should be considered as a set of signals for making design decisions on strengthening mine workings.

The perspective of discovery of zonal disintegration phenomenon of rocks around underground mine workings is analyzed. The methodological stages for research of this phenomenon are shown. The physics of zonal disintegration of rocks around underground mine workings is disclosed. There are described the possibilities of advanced entropy method and developed energy method that allow to investigate a phenomenon of zonal capsulation of underground mine workings. The sequence of research of this phenomenon parameters is presented. The order of choice of stable shape and resource-saving support in underground mine workings is substantiated, for the deep horizons of the Kryvorizkyi Iron-Ore Basin mines. The method of parameters calculation of self-regulating roof-bolting in underground mine workings is substantiated, which allows to use the rock pressure energy. The design of a self-regulating roof-bolting is developed, which allows applying metal, polymer and rope bolts. The economic efficiency of rock pressure energy usage is substantiated in case of support setting at great depths in underground mine workings.

Nearly 10,000 miles (16,000 km) of underground mine workings began flooding on April 22, 1982 when the large pumps used to dewater the mines of Butte, Montana were shut off. In the first few months, water levels in the workings rose hundreds of meters. Flooding continues to this day at a slower rate, nearly 25 years later. An early evaluation of the water chemistry in the flooding mines suggested that the initially poor water quality was the result of flushing of a reservoir of stored acidity and metals. However, a detailed water balance for the Berkeley pit, underground workings, and associated mining features suggests an alternative explanation. During the early period of mine flooding, acidic surface water from the deactivated heap leach operations and nearby acid rock drainage were routed into the empty Berkeley Pit, and thence drained downward and outward into the underground mine workings, causing widespread degradation of water quality in the underlying workings. After 21 months, the hydraulic gradients in the system reversed, causing a change in the direction of ground water flow and a gradual improvement in water quality of the mine shafts.

Background: Describe the current situation of anxiety and depression among underground mining workers at some coal mines in Quang Ninh in 2022-2023. Methods: A cross-sectional survey was conducted on 180 underground coal miners in 02 coal mining companies in Quang Ninh. Research tools are the Zung anxiety scale and the Beck depression scale, which are utilized and evaluated according to the technical regulations of occupational and environmental health. Results: 15% of the study subjects had mental health problems, including 7 people (3.9%) with anxiety disorders and 10 people (5,6%) with depression, 10 people 5.6%) had both mental health problems: anxiety and depression. 8,9% (16 people) have mild anxiety disorder; there was 1 person with severe anxiety disorder. Among the subjects with depression, 15 people (8.3%) had mild depression; 2 subjects had moderate depression and 3 subjects had severe depression through the Beck test. Conclusion: 15% of the total 180 subjects studied, who are laborers working in underground coal miners at two coal mines in Quang Ninh had mental health problems (anxiety and depression), which is a relatively high rate. Larger studies are needed on the mental health status of underground coal miners to identify at-risk groups and related factors for effective early intervention measures. Keywords: coal miners; mental health; anxiety; depression.

Introduction. In the last ten years throughout the whole world there has been a steady tendency towards mining economic minerals at greater depths which is accompanied both by deterioration in the mining and technical conditions for working deposits and by active development of mine pressure. Of particular importance and significance in this aspect is the large-scale scientific and technical problem of creating safe technologies for working deposits of economic minerals at considerable depths, including unmanned working. It is generally accepted that scientific bases of mining technology are a fundamental knowledge of the geomechanical and physical processes in blocks of Earth around underground workings which occur due to disturbance of the original condition of rock masses by the cavities formed. As numerous full-scale experiments show, the block structure of rock masses, geotectonics, and the seismicity of regions have a considerable effect on the nature and features of the geomechanical and physical processes around underground mine workings. In the light of past achievements in geomechanics, geotectonics, and seismology some connections for these disciplines are clearly developed. Among key points in particular is the discovery of zonal disintegration of rocks around underground workings [1, 2], the variable sign of the reaction of rocks to dynamic effects [3, 4], and also a number of other physical factors [5-9] pointing to the particularly nonlinear behavior of rocks. Mainly these are the existence of an "invariant" ratio of the linear dimensions of rock blocks to the amount of crack opening in the structural hierarchy of rock masses/z~(6) [8],* the process of self-blocking of "composite" materials leading to formation of a cellular structure in the form of a passive core and an active supporting shell [5], and also detection of a new type of low-velocity waves whose elementary carriers are geoblocks of a different hierarchical level and exhibiting rapid dispersal [6, 7]. It is possible to show that there is a profound interconnection between all of these effects which is caused by the existence of the phenomenon of zonal disintegration of rock around underground workings [1] and the alternating sign of rock reactions to dynamic effects [4]. Apart from a desire to illustrate, although partially, this intercormection, a stimulus for this work is the requirement for attributing the curious, in our view, results of comparing the effects which are obtained on the basis of these two discoveries with a number of basic factors from the field of Earth physics and geotectonics recently accumulated by geologists and geophysicists, and which have not so far found any satisfactory explanation from a physical viewpoint. As geological and geophysical factors the authors have in mind mainly the following: 1) the structure of the Gutenberg velocity section of Earth for longitudinal and transverse waves; 2) subdivision of the geological history of Earth into five sections of approximately the same duration (1 billion years): Catarchean, Archean, Aphebian, Riphean, and Phaneroan; 3) separation of 19 tectomagnetic epochs in Earth starting from an age of 3.54 billion years and a final age of 0.093 billion years, with an average period of 170-200 million years; 4) paleoclimatic recurrence; 5) cyclic changes of the overall area of modern continent territories covered by seas;

In the process of underground coal mining a complex network of vertical, horizontal and inclined mine workings with the purpose of extraction, transportation and evacuation to the surface are utilized. The mining workings are also being utilized for ventilation network system, which is also used for ensuring the oxygen supply necessary for workers, as well for diluting explosive gases and/or toxic substances and, ultimately, for exhausting the heat resulted from underground workings. For air flow pumping, special fans, of high capacity, located at the surface of the main ventilation stations are used. The fan operating mode depends on aerodynamic parameters and also on the structure of the ventilation network. Knowledge of specific local network parameters leads to the optimization of air flow distribution. The novelty presented in the paper consists in analysing and optimising the complex ventilation networks of Lonea mining unit, based on the depresiometric, flowmeters measurements and the status parameters specifics to each branch. Worldwide, in high developed mining countries, solving a complex ventilation networks it s being carried out with the help of specialized software such as VentSim, VentGraft, VentPri, 3D Canvent etc., through discontinuous operating at the mining unit quarter or to a distant location, where upon the results obtained are presented to the ventilation specialists. The complex ventilation network afferent to Lonea mining unit was rendered, fixed and optimised, up-to-date, using 3D Canvent software.

&amp;lt;p&amp;gt;The underground space, which is not used for mining purposes, now serves more like a room for storing various goods, for organizing the production of goods, as mining museums, etc.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Using such space creates some dualism in its maintenance. On the one hand, it is simply an underground space, used as a storage, on the other hand the characteristics of this space are completely dependent on the natural conditions and properties of the rocks surrounding the mining workings. This is especially true for mining space used as mining museums, where it is unacceptable to cover mining workings walls with solid concrete support that will simply destroy the authenticity of the object. Whether it is necessary to have a mining engineer in the staff of such a museum?&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The authors hold to the concept that regulations for the use of each underground space for use as a museum must be developed by professionals, but this space should be managed by ordinary museum workers, just as it is not necessary to be a professional mechanic to drive a car.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Besides the air conditioning, removing the water one of the most serious problems in the use of unsupported underground space is the control of the stability of the roof and walls of the workings to provide safety for visiting this museum people.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The authors propose some solutions to control the stability of mining workings using instrumental observation methods developed specifically for unprofessional workers in such underground museums.&amp;lt;/p&amp;gt;

The opening of any underground mining work requires a check and the establishment of the regime of explosive and toxic gas emissions (methane and carbon dioxide). Establishing the regime of gas emissions is necessary to clearly establish the correct choice of specific machinery in construction Ex. or not, as well as the correct sizing of the vent. The purpose of this paper is to determine the rate of methane (explosive gas) and of carbon dioxide (axphysants gas) in the mine workings of Valea Sărată salt mine newly opened salt mine. For the preparation of the documentation, the following elements were taken into account: -The geological conditions of the salt deposit in the Valea Sărată mining perimeter; -Existing records and documentation regarding previous occurrences of gas and their manifestation; The results of quantitative and qualitative measurements in underground mining works, regarding: -circulated air flows; -gas concentrations: methane, its counterparts and carbon dioxide; Establishing the release of gases in the underground atmosphere of the mining works. Based on the measurements and observations made, as well as the analysis of the previously mentioned elements, the underground mining works were included.

Currently in Romania there are six salt mines which exploit the salt through underground mine workings: Dej salt mine, Tg. Ocna salt mine, Slanic Prahova salt mine, Ocnele Mari salt mine, Cacica salt mine, and Praid salt mine. The purpose of the present paper work is to establish the methane release (explosive gas) and the carbon dioxide release regime in mine workings from Praid salt mine in order to classification. This verification of the Ocnele Mari salt mine classification has been carried out during September 2021 and there have been taken into account the following elements: - Geological and technical-mining conditions of the salt deposit related to Dej mining perimeter; - Results of the quantitative and qualitative measurements from the underground mine workings regarding: a) Circulated air flows; b) Measured methane and carbon dioxide concentrations; c) Absolute flows registered; d) Accumulation capacity of gas in the deposit; e) Gas concentrations and pressure in the massif. - Existing evidences and documentations regarding the previous gas occurrences and their manner of manifestation; - Establishing the way in which the gas is released into the underground atmosphere of the mine workings. Based on the observations and on the carried out measurements, on the analysis of the studied geological and mining elements, there has been made the classification proposal of the Ocnele Mari salt mine from the point of view of gas emissions (methane and carbon dioxide)

Theoretical model for calculating and adjusting radon activity concentration in ventilation networks of uranium mines considering pressure drop effect

The purpose of the paper is to present the possibilities of the three-dimensional representation of geological strata in underground (access) workings in a hard coal deposit in the SW part of the Upper Silesian Coal Basin, using CAD software and its flagship program AutoCAD. The 3D visualization of the results of underground workings’ mapping is presented and illustrated on two opening out workings (descending galleries). The criteria for choosing these workings were based on their length and the complexity of geological settings observed while they were driven. The described method may be applied in spatial visualization of geological structures observed in other deposits, mines and existing workings (it is not applicable for designing mine workings), also beyond the area of the Upper Silesian Coal Basin (USCB). The method presented describes the problem of the visualization of underground mine workings in a typical geological aspect, considering (aimed at) detailed visualization of geological settings revealed on the side walls of workings cutting the deposit.