Modern Mine Research Articles

The risk reducing of miners evacuation in case of an accident with aerological impact

Displacement of miners along emergency escape routes involves various types of risk. First of all, displacement of miners occurs rapidly in order to have time gap to carry out the evacuation within the operational time according to the emergency recovery plan. Further, the evacuation is carried out along routes that arranged far worse compared to that ones for the displacement of miners to their workplaces as well as escape routes provided with emergency ways. Further, strict compliance with regulations of the Safety Regulations for displacement along the gassy area of the route until reaching the nearest fresh stream and, after that, displacement exclusively along the clean stream, in some cases significantly increases the route length. For example, in case, when switching points as duplicate self-rescuers could be used, the exit during the operational time of the emergency recovery plan could be unreachable, while organizing of the second switching point is prohibited by the Safety Regulations, etc. In addition, the risk of emergency evacuation is due to the fact that, unlike classical route tasks, routes are built not “from point to point”, but from the initial set (the position of the emergency recovery plan) to the final one (the set of exits to the surface of mine shafts involved for evacuation). The individual risk differs for certain groups of miners evacuated from the workings according to the position of emergency recovery plan. Therefore, the study is devoted to the elaboration of a method reducing the risk of emergency evacuation with a probable (within acceptable limits) violation of the requirements of the Safety Regulations as well as correcting these regulations. Strict compliance with regulations of the Safety Regulations is able to complicate the emergency evacuation process. In modern mines provided with long and complicated ventilation networks, due to an exogenous fire outbreak, large gassy areas could be formed, which are, able to cause complications during emergency evacuation. Bypassing these areas means increasing the evacuation time that could lead to the exceeding of operational time according to the emergency recovery plan An algorithm for correction of escape routes is proposed, which, provided that real information about possible escape routes is obtained by means of an emergency simulation, will make it possible to shorten these routes, although they contain clean and gassy areas alternately. The algorithm is recommended for the discussion purpose in order to correct some regulations of the Safety Regulations. Keywords: emergency recovery plan, mine ventilation network, gassy area, emergency escape routes.

Reforestation improves vegetation coverage and biomass, but not spatial structure, on semi-arid mine dumps

Modern mine rehabilitation aims at thorough restoration of an ecosystem with emphasis on not only land area covered by vegetation but also the structure and function of that vegetation. However, assessment of current restoration success reveals a lack of attention to the spatial structure and its relationships with vegetation coverage and biomass. A forest's spatial structure is an important attribute of structural diversity. Complex spatial structures mean diverse species composition and spatial dissimilarity, which can provide a base for self-sustaining and regeneration. This study uses WorldView-2 images and field data to train the mind evolutionary algorithm-back propagation neural network (MEA-BP) model for the purpose of mapping three parameters (coverage, biomass, and spatial structure) across mine dumps. The results show that the spectral and textural features could effectively assess the coverage, biomass, and spatial structure, with an R2 of 0.91, 0.86, and 0.62, respectively. The coverage is positively correlated with biomass, while the spatial structure is negatively correlated with coverage and biomass. Pure Hippophae rhamnoides L. had high coverage but very low spatial structure, while the mixed community dominated by Populus L. and Pinus tabulaeformis Carr had high coverage, high biomass, and medium structure at around 10 years. The results suggested that the artificial reforestation improves vegetation coverage and biomass but did not synchronously increase spatial structure. The initially planted species composition, substrates, and succession process have a significant influence on the forest parameter relationships. The future reforestation and optimization of community assemblages should take the relationships and their influence factors and effects on ecosystem services into account. The remote sensing-based data and model has potential and advantages in dynamically guiding the rehabilitation and monitoring of the restored ecosystem.

A Study of Millisecond Blasting on High Bench at Barun Iron Ore Operation

To improve the productivity and efficient of modern large-scale open-cut mines, a number of technologies are developed and trialed, including new blasting equipment, larger blasting holes, high benches, air spacing, and short-delay blasting within holes. However, the relative blasting parameters need field calibration and further investigation of theories on these techniques are required. This paper studied the open-cut bench blasting at Barun Eboxi Mine of Baotou Iron and Steel Group via theoretical analysis on shock wave, numerical simulation, and field test. According to the technical conditions of the site, three sets of vertical boreholes at 310 mm diameter were drilled on 24 m high batter; and three sets of air-spaced charges were set up. The digital electronic detonator was used to initiate at millisecond intervals. The study found that under the condition of 24 m high bench, the use of intermediate air interval is beneficial to the rock fragmentation. The delay time within the hole is 3-8 ms. The bottom of the lower explosives and the top of the upper explosives were devised for initiation to optimize the initiation location. The peak effective stress points are 63.6%, 52.2%, and 8.9% higher, respectively. The field test of high-bench intrahole millisecond blasting in Barun Eboxi mine shows that the intrahole millisecond blasting parameters proposed in this study are feasible.

A Bayesian Network Approach to Evaluating the Effectiveness of Modern Mine Hunting

This paper describes a novel technique for estimating how many mines remain after a full or partial underwater mine hunting operation. The technique applies Bayesian fusion of all evidence from the heterogeneous sensor systems used for detection, classification, and identification of mines. It relies on through-the-sensor (TTS) assessment, by which the sensors’ performances can be measured in situ through processing of their recorded data, yielding the local mine recognition probability, and false alarm rate. The method constructs a risk map of the minefield area composed of small grid cells (~4 m2) that are colour coded according to the remaining mine probability. The new approach can produce this map using the available evidence whenever decision support is needed during the mine hunting operation, e.g., for replanning purposes. What distinguishes the new technique from other recent TTS methods is its use of Bayesian networks that facilitate more complex reasoning within each grid cell. These networks thus allow for the incorporation of two types of evidence not previously considered in evaluation: the explosions that typically result from mine neutralization and verification of mine destruction by visual/sonar inspection. A simulation study illustrates how these additional pieces of evidence lead to the improved estimation of the number of deployed mines (M), compared to results from two recent TTS evaluation approaches that do not use them. Estimation performance was assessed using the mean squared error (MSE) in estimates of M.

A study of innovative cut blasting for rock roadway excavation based on numerical simulation and field tests

Drilling and blasting is a common excavation method in underground engineering. In modern mine construction, improving the efficiency of rock roadway excavation is a significant issue. With the development of blasting practices and the deepening technical understanding, it is difficult to implement deep-hole blasting with traditional drilling and blasting. The reason is that conventional cut blasting makes it difficult to fully throw out rock masses and create enough free surface. In this paper, an innovative cut blasting technology based on cavity cutting and fragment throwing (CCFT) is studied. It overcomes the limitation of dense hole layout, but strengthens the charge at the bottom, and forms a more sufficient cut cavity through a two-stage explosion. Based on the above ideas, a parallel cut with a double fragment-throwing hole (P-DFH) was designed for the excavation of rock roadways. The effects of CCFT cut blasting were studied at the mesoscopic and macroscopic levels. The smoothed particle hydrodynamics-finite element method (SPH-FEM) was used to establish a P-DFH model. The mechanism of cut cavity formation was studied. The arbitrary Lagrange-Euler with erosion algorithm (ALE-EROSION) was used to establish a global geological model for roadway excavation, and the evolution of rock failure in stages was analyzed. Finally, a field test was conducted to verify the effectiveness of the CCFT technique through monitoring. The application of the CCFT technique has achieved significant results for improving face advance, protecting surrounding rock, and controlling blasting vibration.

Modern mine scattering systems

For years, mine weapons have been irreplaceable on the battlefield. Using of fully mechanized mine scattering systems made it possible to reduce the direct exposure of soldiers to the enemy's fire, minimize losses and significantly hasten the work. The article presents a comparative analysis of modern mine scattering systems, as well as outlined further research directions related to this topic. Key words: mine explosive barriers, mine scattering systems, pyrotechnic systems

Modelling Large Heaped Fill Stockpiles Using FMS Data

The frequent best practice for managing large low-grade run-of-mine (ROM) stockpiles is to average the entire stockpile to only one grade. Modern ore control and mineral processing procedures need better precision. Low-precision models hinder the ability to create a digital mine-to-mill model and optimize the holistic mining process. Prior to processing, poorly characterized stockpiles are often drilled and sampled, despite there being no geological reason for relationships between samples to exist. Stockpile management is also influenced by reserve accounting and lacks a common operational workflow. This paper provides a review of base and precious metal run-of-mine (ROM) pre-crusher stockpiles in the mining industry, and demonstrates how to build a spatial model of a large long-term stockpile using fleet management system (FMS) data and geostatistical code in Python and R Studio. We demonstrate a framework for modelling a stockpile believed to be readily workable for most modern mines through use of established geostatistical modelling techniques applied to the type of data generated in a FMS. In the method presented, each bench of the stockpile is modeled as its own geological domain. Size of dump loads is assumed to contain the same volume of material and grade values that match those of the grade data tracked in the FMS. Despite the limitations of these inputs, existing interpolation techniques can lead to increased understanding of the grade distribution within stockpiles. Using the framework demonstrated in this paper, engineers and stockpile managers will be able to leverage operational data into valuable insight for empowered decision making and smoother operations.

Modeling Mine Workforce Fatigue: Finding Leading Indicators of Fatigue in Operational Data Sets

Mine workers operate heavy equipment while experiencing varying psychological and physiological impacts caused by fatigue. These impacts vary in scope and severity across operators and unique mine operations. Previous studies show the impact of fatigue on individuals, raising substantial concerns about the safety of operation. Unfortunately, while data exist to illustrate the risks, the mechanisms and complex pattern of contributors to fatigue are not understood sufficiently, illustrating the need for new methods to model and manage the severity of fatigue’s impact on performance and safety. Modern technology and computational intelligence can provide tools to improve practitioners’ understanding of workforce fatigue. Many mines have invested in fatigue monitoring technology (PERCLOS, EEG caps, etc.) as a part of their health and safety control system. Unfortunately, these systems provide “lagging indicators” of fatigue and, in many instances, only provide fatigue alerts too late in the worker fatigue cycle. Thus, the following question arises: can other operational technology systems provide leading indicators that managers and front-line supervisors can use to help their operators to cope with fatigue levels? This paper explores common data sets available at most modern mines and how these operational data sets can be used to model fatigue. The available data sets include operational, health and safety, equipment health, fatigue monitoring and weather data. A machine learning (ML) algorithm is presented as a tool to process and model complex issues such as fatigue. Thus, ML is used in this study to identify potential leading indicators that can help management to make better decisions. Initial findings confirm existing knowledge tying fatigue to time of day and hours worked. These are the first generation of models and future models will be forthcoming.

Beyond Privacy: Protecting Data Interests in the Age of Artificial Intelligence

Serious challenges are raised by the way in which technology companies like Facebook and Google harvest and process user data. Companies in the modern data economy mine troves of data with sophisticated algorithms to produce valuable behavioural predictions. These data-driven predictions provide companies with a powerful capacity to influence and manipulate users, and these risks are increasing with the explosive growth of ‘Big Data’ and artificial intelligence machine learning. This article analyses the extent to which these challenges are met by existing regimes such as Australia and New Zealand’s respective privacy acts and the European Union’s General Data Protection Regime. While these laws protect certain privacy interests, I argue that users have a broader set of interests in their data meriting protection. I explore three of these novel interests, including the social dimension of data, control and access to predictions mined from data and the economic value of data. This article shows how existing frameworks fail to recognise or protect these novel interests. In light of this failure, lawmakers urgently need to frame new legal regimes to protect against the worst excesses of the data economy.

Decline of novel ecosystems used by endangered species: the case of piping plovers, least terns, and aggregate mines

AbstractSand and gravel mining creates novel ecosystems along the Platte, Loup, and Elkhorn rivers in Nebraska, USA. Piping plovers and least terns are state and/or federally threatened and endangered species, respectively, that nest and raise young at these sites and their derivatives. Despite hosting relatively large numbers of piping plovers and least terns for decades, an important question that has largely gone unaddressed is whether the industry that has produced these novel ecosystems is stable and will continue to produce habitat consistently in the future. We evaluated how the number, size, and spatial distribution of different site types hosting different numbers of nesting plovers and terns have changed over time and how current trends in the number of different site types will affect future habitat using a multi‐state modeling approach. Overall area and total number of sites declined during the period 1993–2020. More important, one site type, traditional mines, are being replaced by another site type, modern mines, which host lower numbers of nests of both species. The difference between these two site types is primarily how waste sand is stored. Traditional mines store waste sand in spoil piles or plumes along the edge of a lake created by the mining process, forming relatively large expanses of nesting habitat used by both species. Modern mines store waste sand in limited quantities along the edge of the lake but also in piles away from the lake. Traditional mines also differ from modern mines in that they are routinely converted to housing developments with intermediate transition sites that host the largest number of nests for brief periods. Based on the previous 28 yr of decline, traditional mines and their productive derivatives are projected to continue to decline, thereby further reducing overall nesting habitat. Piping plovers and least terns are expected to nest in our study sites for the foreseeable future, but overall numbers are expected to be smaller than what has been observed in previous decades. Local declines in our study area will have local and regional implications for the recovery and management of these two species of conservation concern.

Обеспечение взрывобезопасности шахтного расходомера метана при эксплуатации, а также при первичной и периодической поверках

At the mines where hazardous and threatening with sudden outburst emissions coal seams are developed, it is required to conduct a current forecast of the coal seams outburst hazard, which is based on an estimate of methane consumption from the control drill holes. Previously, the gas flow rate was measured using PG2-MA and IG-1 pressure gauges. Pressure gauges have some significant drawbacks. Their capillaries are regularly clogged with coal dust coming out from the control drill hole, which results in distortion of the measurement results. Pressure gauges do not register measured flow rate values, they do not have compensation for temperature errors. Metrological support is developed for pressure gauges that reduces the forecast accuracy and reliability. For eliminating above shortcomings, the development of modern mine methane flow meters was conducted based on the hot-wire measurement principle with electronic processing of the measured information. Cross-sectional area of the flow meter primary sensor is dozens of times larger compared to the pressure gauges, therefore the coal dust does not clog the gas path. The temperature error is automatically corrected. High-speed response ensures recording the real dynamics of gas release from the control drill hole. Several additional service functions are implemented. For electronic flow meters, the metrological support is developed and certified in accordance with the established procedure, including a method for checking the device with clean air (instead of methane) and an exemplary installation. Due to special circuitry solutions, the explosion-proof design of the CoalAwakeningBeast device with the type of protection «intrinsically safe electrical circuit» is provided, which is confirmed by the results of testing the flowmeter in the laboratories of MakNII and VostNII. Industrial tests conducted at the mines in four coal-mining basins confirmed the functionality of the device. In the Karaganda Technical University based on the development of Scientific and technical producer's cooperative NTPK Microclim (Karaganda, Kazakhstan), preparations are being made for a small-scale production of CoalAwakeningBeast flow meters.

Impacts of the Covid-19 pandemic on traditional oil mining at Wonocolo Village Kedewan Sub-District Bojonegoro Regency East Java

Mining in the world consists of modern and traditional mining. Various studies have discussed how field workers were precarious at being exposed to Covid-19 in modern mining. Many studies discuss ways of modern mines overcoming Covid-19, but discussion of research related to the impacts of Covid-19 on traditional mining has not been carried out. This study addressed the effect of the Covid-19 pandemic on traditional oil mining in Wonocolo, Bojonegoro Regency. This work is a descriptive study using observation and in-depth interviews and reviewing secondary data related to conventional mining activities. The results showed that the Covid-19 pandemic has an indirect effect on traditional oil mining activities in Wonocolo. The pandemic caused a decrease in demand, a drop in selling prices, lower production, and temporary closure of wells in Wonocolo traditional mining. In contrast, Covid-19 did not directly affect miners’ activities since the miners believed that Covid-19 could not infect them due to the very extreme condition in the mining area that the Coronavirus would not survive.

Digitalization of hydrogeological processes in mining industry

The groundwater monitoring reconstruction and hydrogeological digitalization are discussed on the ground of the past and modern mine flooding protection technologies and geo-information technologies. According to the authors, it is of the current concern to advance digitalization technologies for hydrogeological processes in the mining industry to be focused on: – operative and episodic control and display of water condition at the control point in the x, y, z, t coordinates, including pore pressure, temperature, mineralization, flow rate of drainage water intake devices, productivity of pumping equipment of mine and quarry drainage, water-development in pit walls, in underground mines, in the influence zone of mining production; – creation of permanent hydrogeological models of groundwater flow, pore pressure distribution, flow gradients and transport of pollutants within the framework of conceptual and numerical models of subsoil, mining facilities, terrain, natural environment and anthropogenic activity in the influence zone of mining. The article discusses the working cycles of digitalization of operational and occasional monitoring data on the status of groundwater at the control points and 3D representations of groundwater flow, distribution of pore pressure, pressure gradients and movement of pollutants using constantly operating models to ensure safe and competitive development of flooded mineral deposits in modern conditions. The relevance of the digitalization technologies for hydrogeological processes based on the latest achievements in the field of geoinformatics and automation of hydrogeological work is substantiated.

Behavior of Fully Encapsulated Cable Bolt in Various Double-Shear Methods and the Sequence of Wire Failure in the Newly Developed Shear Apparatus

The use of long-tendon ground support elements (cable bolts) is now a common practice in modern underground coal mines, hard rock mines, tunnels, and other underground structures. The paper briefly introduces the development of test methods for rock and cable bolts, including single- and double-shear methods, in the last 30 years and focuses on the novel development of the fourth generation of cylindrically shaped shear test apparatus (MK-IV Double Shear Box) for assessing tendon performance in shear based on the experience gained from the development of previous versions of shear experiment apparatus. The results were compared with similar test findings using a rectangular-shaped double-shear apparatus with and without friction across joint faces. The sequence of wire failure was studied by using the newly developed double-shear test apparatus, and the performance of abnormal phenomena in the double-shear tests was analyzed. The sequence of wire failure can be inferred based on the positive and negative values of strain gauge readings, and the wire of cable bolt under shearing may be broken in the joint area. The failure possibly occurred from one side to the other instead of from top to bottom. The modified double-shear test apparatus with a long section of concrete cylinder was proposed to conduct further research on cable bolt debonding.

Sustainable Rehabilitation of Surface Coal Mining Areas: The Case of Greek Lignite Mines

Surface lignite mines of the Balkan Peninsula face growing pressure due to the CO2 emissions reduction initiatives, rapidly increasing renewable-power capacity, and cheap natural gas. In this frame, the development of a modern mine land rehabilitation strategy is considered as a prerequisite for mitigating the social and economic impacts for the local communities. In the case of western Macedonia lignite mines, these prospects are investigated based on a PEST (political, economic, social, technological) analysis of seven alternative land uses. Urban (industrial) development, green houses, and industrial heritage parks are considered as the most appropriate land uses for mitigating the socioeconomic impacts due to the loss of employments. For the land uses occupying large areas (i.e., agriculture, forestry, livestock farming, and photovoltaic parks), an optimisation algorithm is proposed for determining the mix of land uses that maximise revenue, equity, and natural conservation and minimise investment. The algorithm was applied using the opinions of 10 experts, who were involved in mine land reclamation projects carried out in the western Macedonia region in the recent past. According to the results obtained, photovoltaic parks are rated as a more attractive investment than extensive agriculture, as regards the anticipation of revenues, while livestock farming and forests are necessary to safeguard the ecosystem’s functions.

Research on environment optimization system of mining operation area based on modern open-pit mine geological structure

After studying a large number of mining and excavation sites, the author of this article sampled and analysed the geological structure of the collection area. By comparing the soil geological structure, the degree of environmental damage caused by the excavation process was studied, and a variety of open-pit mine geological structures were analysed and studied. After analysing the relevant data, a modern open-pit mine geological structure of the mining operation area environment optimization system was established. This system can integrate the existing resources of the mine based on the analysis and restoration of ecological vegetation and enter the corresponding parameters., Can design a 3D landscape planning mottled corridor matrix spatial pattern model, combined with the current situation of abandoned land in mining and can be combined with corresponding landscape design strategies (such as artistic aesthetics), the system has the design points of modern engineering technology, in the beautification of the environment Utilizing the existing geological conditions to optimize the environment of the mining operation area has an important auxiliary role.

Mechanical Properties of Welded Joints of 1.3964 Steel for Computer Aided Engineering (CAE) Purposes

Abstract The article presents the study of mechanical properties of welded steel from which the hull of a modern mine destroyer was made. Keeping the tightness of ship compartments during operation depends on the strength of these joints. The results of testing the mechanical properties of 1.3964 steel and its welded joints subjected to a static tensile test were presented, and a Johnson – Cook material model was proposed. The material model can be used in CAE (Computer Aided Engineering) simulations related to hull strength analysis.

Detection of abandoned water-filled mine tunnels using the downhole transient electromagnetic method

Many abandoned water-filled mine tunnels at unknown locations in major coal fields in China pose a hazard to the safe production in modern mines. Geophysical methods with rapid and accurate determination of the location and size of the tunnels are needed. The downhole transient electromagnetic method (TEM) applied in a borehole has significant potential for detection. A 3D finite-difference time–domain (FDTD) modelling method was used to simulate the anomalous response and parameter influence in conjunction with a model of a water-filled tunnel. The results show that the method gives a clear response and has distinct benefits for the detection of water-filled tunnels. Three components of the response signal were collected in an exploration hole in the vicinity of an abandoned mine in Shaanxi Province, China. The three components of the signal, especially the horizontal components, indicated obvious anomalies. We compared three different inversion procedures: (1) using three components of the total (primary + anomalous) field; (2) three components of the anomalous field and (3) using the horizontal components of the anomalous field. The results of the three inversions are almost the same and accord with the exploration result from densely distributed exploration boreholes nearby test borehole. The study showed that the downhole TEM effectively solves the problem of detecting and locating water-filled tunnels in the vicinity of a borehole. This information is a valuable complement to the geophysical detection of abandoned coal mine tunnels.

Innovative approach based on roof cutting by energy-gathering blasting for protecting roadways in coal mines

As underground mining progresses to deeper levels, roadway control has become a significant issue in the development of modern mines with characteristics of a high yield and high efficiency. To protect deep roadways from dynamic disasters, an innovative approach based on cutting the roof by energy-gathering blasting for protecting the roadway (CREGBPR) was studied. First, the key technique of energy-gathering blasting was introduced. CREGBPR was developed by using the blasting technique and to directionally cut the roof above the roadway following a specific design. Theoretical analysis, numerical simulation, and field tests were combined to analyze the roadway control mechanism of CREGBPR. Compared with the original approach, the CREGBPR approach uses the broken and expanded rock mass to support the fractured structure of the main roof, reducing the impact on the retained roadway. Furthermore, the improvement in the structure eliminates the roof overhanging the roadway coal pillar. The pillars can serve as integrated supporting bodies that bear the abutment stress. Meanwhile, the stress environment is improved significantly by the roof cutting effect; the stress evolution includes new areas in which the stress distributes more uniformly. As a result, these independent effects induced by CREGBPR are integrated to protect the roadway effectively. A field test was conducted to verify the effectiveness of CREGBPR. The roadway convergence and roof weighting were significantly reduced. The research results prove that the CREGBPR approach is feasible for engineering applications and can protect roadways in deep mines.

Improving Coal Quality Estimations with Geostatistics and Geophysical Logs

In most modern coal mines, there are many coal quality parameters that are measured on samples taken from boreholes. These data are used to generate spatial models of the coal quality parameters, typically using inverse distance as an interpolation method. At the same time, downhole geophysical logging of numerous additional boreholes is used to measure various physical properties but no coal quality samples are taken. The work presented in this paper uses two of the most important coal quality variables-ash and volatile matter-and assesses the efficacy of using a number of geostatistical interpolation methods to improve the accuracy of the interpolated models, including the use of auxiliary variables from geophysical logs. A multivariate spatial statistical analysis of ash, volatile matter and several auxiliary variables is used to establish a co-regionalization model that relates all of the variables as manifestations of an underlying geological characteristic. A case study of a coal mine in Queensland, Australia, is used to compare the interpolation methods of inverse distance to ordinary kriging, universal kriging, co-kriging, regression kriging and kriging with an external drift. The relative merits of these six methods are compared using the mean error and the root mean square error as measures of bias and accuracy. The study demonstrates that there is significant opportunity to improve the estimations of coal quality when using kriging with an external drift. The results show that when using the depth of a sample as an external drift variable there is a significant improvement in the accuracy of estimation for volatile matter, and when using wireline density logs as the drift variable there is improvement in the estimation of the in situ ash. The economic benefit of these findings is that cheaper proxies for coal quality parameters can significantly increase data density and the quality of estimations.