Mine Galleries Research Articles

Non-invasive research of tunneling heritage in the Ypres Salient (1914–1918) – research of the Tor Top tunnel system

Abstract During the First World War, the stalemate in the trenches resulted in the creation of a vast network of field defences in different theatres of war. The rediscovery of ancient siege techniques, such as military mining and the ever-increasing power of artillery fire, resulted in the creation of an underground world of tunnels and mine galleries deep below the surface. This paper explores the potential of integrating war records and non-invasive techniques (historical aerial photographs, geophysical soil-sensing techniques and airborne laser scanning) for the study of this buried war heritage in Belgium.

Continuous monitoring of deformations in mines using laser interferometer–deformograph

The article gives a detail description of the deformation graphing equipment designed at the Institute of Laser Physics, SB RAS, for the geodynamic monitoring of stress state in mine galleries and other underground openings, and for the analysis of ground surface vibrations before earthquakes and other seismic events. The more comprehensive study of separate rock mass blocks uses the advanced modification of the prototype deformograph introduced into service on Talgar testing ground in Kazakhstan. The programming support of the equipment is described.

The Influence of In-Situ Rock Mass Stress Conditions on Deformation and Load of Gateroad Supports in Hard Coal Mine

The stress-strain state of the rock mass in the neighbourhood of the mining galleries is absolutely critical considering their behaviour particularly load and deformation. The stress-strain state can be affected by numerous geological and mining factors i.e. depth, mechanical parameters of the rock mass, the presence of faults, previous mining operations in case of multiple seam extraction and by the influence of the current longwall mining process.Considering this fact the advanced measurement plan was developed. The measurements were conducted in one longwall maingate of the Czech coal mines. The holistic investigation program consisted identification of initial rock mass stress tensor and monitoring of its changing during the approach of the longwall face. Two CCBO (modified overcoring) probes were installed to obtain pre-mining full stress tensor and afterwards three CCBM probes were installed to continuous monitoring stress state in rock mass ahead of advancing longwall. The triple height telltales and endoscopic methods were applied to monitor the behaviour of rockmass in close proximity of the gateroad. Hydraulic dynamometers and strain gauged rockbolts were used to determine the support load. Also the gateroad deformation observations were performed. The results of aforementioned measurements allowed to determine the potential relation between stress-strain rock mass state and behaviour of the investigated gateroad in coarse of longwall face approaching.

Radon: a radioactive therapeutic element

Abstract This paper presents selected issues related to the use of 222 Rn in therapeutic treatments. Radon is a radioactive element whose usage in medicine for more than 100 years is based on the radiation hormesis theory. However, owing to the radioactive character of this element and the fact that its alpha-radioactive decay is the source of other radionuclides, its therapeutic application has been raising serious doubts. The author points to potential sources and carriers of radon in the environment that could supply radon for use in a variety of therapies. Except for centuries-long tradition of using radon groundwaters, and later also the air in caves and underground workings, the author would also like to focus on soil air, which is still underestimated as a source of radon. The text presents different methods of obtaining this radioactive gas from groundwaters, the air in caves, mining galleries and soil air, and it presents new possibilities in this field. The author also discusses problems related to the transportation and storage of radon obtained from the environment. Within radon-prone areas, it is often necessary to de-radon groundwaters that are intended for human consumption and household usage. Also, dry radon wells are used to prevent radon migration from the ground into residential buildings. The author proposes using radon released from radon groundwaters and amassed in dry radon wells for radonotherapy treatments. Thanks to this, it is possible to reduce the cost of radiological protection of people within radon-prone areas while still exploiting the 222 Rn obtained for a variety of therapies. With regard to the ongoing and still unsettled dispute concerning the beneficial or detrimental impact of radon on the human organism, the author puts special emphasis on the necessity of strictly monitoring both the activity concentration of 222 Rn in media used for therapeutic treatments and of its radioactive decay products. Monitoring should be also extended to the environments in which such treatments are delivered (inhalatoriums, baths, saunas, showers, pools and other facilities), as well as to the patients – during and after the radonotherapy treatments. It is also essential to monitor the dose of radon and its daughters that is received by persons undergoing radon therapy. This should facilitate the assessment of the effectiveness of these treatments, which may contribute to a fuller understanding of the mechanisms of radon impact, and ionizing radiation in general, on the human organism. This will make it easier to ultimately confirm or reject the radiation hormesis theory. It is also essential to monitor the effective dose that is received by medical and technical staff employed to deliver the radonotherapy treatments.

Detection of illegal mine voids using electrical resistivity tomography: The case-study of Raniganj coalfield (India)

Unauthorised coal mining activities may result in development of hidden hollows, rat holes, galleries, goafs, shafts etc., which pose great threats of land subsidence, fire, water flooding leading to severe environmental hazards, health problems and safety issues to the local people. Present study deals with delineation and mapping of unauthorised coal mine voids/galleries over an abandoned old mine around Khudia open cast mine, Nirsa, Raniganj coalfield, India. Electrical resistivity tomography (ERT) study comprising Wenner, Schlumberger, Dipole-Dipole, and Gradient arrays has been carried out along three parallel profiles over the affected area. Further joint inversion of all combined arrays has also been carried out using 2.5D resistivity inversion program, to combine the relative advantages of all the arrays, for producing superior results. 2D ERT sections have been generated for the filtered data sets with a constant quality factors and two different current thresholds. The best results have been obtained, from joint inversion of all combine arrays for the filtered data with higher current threshold. The observed resistivity anomalies are well correlated with the depth of coal seam occurrences as observed in the borehole litholog of nearby area. Finally, a geoelectric model of four unauthorised coal mine galleries has been established with their extension and orientation over the study area. The results demonstrate the suitability of the ERT technique through joint inversion of all combined arrays for characterization of illegal coal mine workings.

Multi sensor data fusion for 6D pose estimation and 3D underground mine mapping using autonomous mobile robot

ABSTRACTSimultaneous localisation and mapping by using a robot is indeed a challenging and critically important problem for an accurate 3D underground mine mapping. Using 6D pose information of a robot (x, y and z coordinates and the yaw, pitch and roll angles), the robot vehicle can be tracked, which is very crucial for an accurate mine mapping. The estimation of 6D robot pose on the ground surface is easy and generally accomplished by either the Global Positioning System (GPS) or by putting some artificial visual landmarks. However, in the underground mining environment, the estimation of pose becomes difficult due to the unavailability of the GPS signal and the identification of landmarks (as surface wall of the underground mine is rough). In this paper, an attempt has been made to construct a 3D underground mine map using a prototype mine robot. For this purpose, a strategy for the underground mine robot pose estimation is devised with the help of multi-sensor data fusion techniques. A shaft-encoder (wheel odometry), Inertial Measurement Unit (IMU) and a rotated 2D Laser Scanner is used to improve and rectify the 6D robot pose as well as 3D mine map. An autonomous prototype robot is built up and allowed to navigate in a real underground mine gallery to validate our algorithm. Generated 3D map has been compared with the actual map available. The outputs of this study are highlighted in this paper.

Mining Security Pipe© (TSM)© with Underground GPS Global© (RSPG)© Escape Security Device in Underground Mining

Abstract TSM is escape pipe in case of collapse of terrain. The TSM is a passive security tool placed underground to connect the work area with secure area (mining gallery mainly). TSM is light and hand able pipe made with aramid (Kevlar), carbon fibre, or other kind of new material. The TSM will be placed as a pipe line network with many in/out entrances/exits to rich and connect problem work areas with another parts in a safe mode. Different levels of instrumentation could be added inside such as micro-led escape way suggested, temperature, humidity, level of oxygen, etc.). The open hardware and software like Arduino will be the heart of control and automation system.

Extensometric observation of Earth tides and local tectonic processes at the Vyhne station, Slovakia

Abstract The Vyhne Tidal Station of the Earth Science Institute of the Slovak Academy of Sciences is located in the former mining gallery of St. Anthony of Padua in the Vyhne valley, Štiavnické vrchy Mts., Central Slovakia. It is equipped with a 20.5 metre long quartz-tube extensometer measuring Earth’s tides, and long-term tectonic deformations of the Earth’s crust. Data between 2001 and 2015 with some diverse gaps were digitally collected, processed and analysed. The effects of the local conditions, such as structure of the observatory, cavity effect, topography and geological features of the surrounding rocks, were investigated in detail and these effects were taken into consideration during the interpretation of the results of the data analysis. Tidal analysis of the extensometric data between 2005 and 2015 revealed that the measured tidal amplitudes are close to the theoretical values. The tidal transfer of the observatory was also investigated by coherence analysis between the theoretical and the measured extensometric data. The coherence is better than 0.9 both in the diurnal and semidiurnal band. The effect of the free core nutation resonance was also investigated in the case of the K1 and P1 tidal components. Since the K1/O1 ratio was about the theoretical value 0.8, than the P1/O1 was between 1.0 and 1.15 instead of the theoretical value of 0.9. The rate of the long-term strain rate was also investigated and the obtained −0.05 μstr/y shows a good agreement with the strain rate inferred from GPS measurements in the Central European GPS Reference Network.

An automatic approach for the control of the airflow volume and concentrations of hazardous gases in coal mine galleries

Intelligently controlling ventilation networks after an abnormal air branch is difficult. The key variable-frequency mine ventilator control factors that are used to correct this phenomenon were discussed. To improve the fitting accuracy of the mine ventilator characteristic curves, a database of characteristic curves for mine ventilators operating at different frequencies was established using the interpolation method for optimizing uniform approximations by Chebyshev. The concept of frequency sensitivity analysis by analyzing the sensitive branch in the ventilation network was proposed. The linear function between the mine ventilator working frequency and branch wind quantity was fitted out by experiments. A model based on Tikhonov regularization measured the branch wind quantity to calculate the wind resistance in the ventilation network, which yielded a unique branch resistance model solution. The mine air was monitored by calculating the variable wind resistance from the branch wind quantity. The sensitive branch coupling in the mine ventilator variable-frequency controlled ventilation was analyzed and combined with the control theory for ventilation networks. Two types of variable frequency were controlled to adjust the branch wind quantity, the frequency-concentration (f-w) servo control method and the curve search method. The experimental model was established for the Da Liu-ta coal mine ventilation system using the mine ventilator variable-frequency system controller to adjust the branch wind quantity. Because gas is explosive, CO2 was used instead of gas for this experiment. The results indicate that the mine ventilator variable-frequency control automatically adjusted the branch wind quantity, which strictly followed the frequency-concentration servo control method and curve search method. Increasing the CO2 concentration caused the mine ventilator variable-frequency controller to increase the branch wind quantity automatically to maintain the CO2 concentration under the threshold value. The experimental results also demonstrated both the practicability of variable-frequency regulation for air branch systems and the feasibility of the branch quantity adjusted theory. Theoretical guidance for adjusting the ventilation branch quantity for a variable-frequency mine ventilator was provided.

An assessment of the creep behaviour of Brazilian salt rocks using the multi-mechanism deformation model

Salt rocks are geomaterials that exhibit several peculiarities, which require a particular approach in rock mechanics. In the field, those rocks are usually found in layered/bedded deposits and in domes or similar structures. Creep is one of the main deformation mechanisms associated with salt rocks, and this phenomenon is highly dependent on the stress state, temperature and mineralogy. Salt rock mechanics for engineering applications requires the definition of a powerful constitutive model and this is an ongoing challenge. Among the many available models, one of the most sophisticated physical constitutive models for salt rocks is the multi-mechanism deformation creep model (MD model). The main contribution of this work is to present a first effort in the use of the MD model for Brazilian salt rocks. Material-sensitive parameters have been calibrated for the Brazilian halite through two methodologies. Salt is modelled as an elasto-viscoplastic material. Numerical simulations using the finite element method have been carried out for triaxial creep tests, Pre-salt wellbore closure and mining gallery convergence in order to validate the parameter set and the methodologies. Excellent results have been observed in most of the applications for validation. Even so, validation efforts should continue to consolidate the parameters and identify possible limitations.

Determination of contamination levels of Pb, Cd, Cu, Ni, and Mn caused by former lead mining gallery.

In the present study, levels of metal contamination caused by former lead mining area were figured out. For this purpose, Pb, Cd, Cu, Ni, and Mn were determined not only in sediment samples taken from different places of the mining area but also in some plants taken around the mining place. In the digestion of plant samples, dry ashing procedure was applied. Flame atomic absorption spectrophotometer (FAAS) was used in the determination of analytes of interest. All the parameters in digestion and detection procedures were optimized to obtain efficient digestion and high sensitivities for analytes. Standard addition and direct calibration methods were applied to find whether there was any matrix interference to affect the determination of analytes. Mn concentration was found to be the highest for each sample analyzed. Lead concentration was found to be between 41 and 249mg/kg in soil/sediment samples and between 2.2 and 1003mg/kg in plant samples. The highest contamination levels for all of the analytes with the exception of Cd were found in current sediment sample.

Evaluation of pre-jamming indication parameter during blind backfilling technique

Hydraulic blind backfilling is used to reduce subsidence problems above old underground water-logged coal mines. This paper describes experimental research on a fully transparent model of a straight underground mine gallery. An automatic data acquisition system was installed in the model to continuously record the sand and water flowrates along with the inlet pressure of the slurry near the model's inlet. Pressure signature graphs and pressure loss curves with bed advancement under different flow conditions are examined. Pressure signature analyses for various flowrates and sand slurry concentrations are conducted to evaluate a pre-jamming indication parameter, which could be used to indicate the arrival of the final stage of filling.

Mechanical behaviors analysis on a square-steel-confined-concrete arch centering and its engineering application in a mining project

Aiming at the support difficulties of mine galleries under the complex geological conditions of high buried depth, high in situ stress and tectonic fractured zones, a novel square-steel-confined-concrete (SSCC) arch centering supporting system is proposed in this paper. To validate the feasibility of this supporting system, a uniaxial compression test on an SSCC short column is performed and the results illustrate that it has better ductility and higher bearing capacity than the U-shaped column. Numerical analysis on the mechanical behaviors of SSCC arch centering is conducted considering three factors of core concrete strength, steel tube thickness and confinable effect coefficient. Two influence indexes of steel tube thickness (μt) and core concrete strength (μc) influencing the ultimate bearing capacity are put forward and μt has more significant influence. Therefore, an SSCC arch centering (side length 150 mm, tube thickness 8 mm and filled C40 concrete) is determined to perform laboratory and in situ experiments. Combined with numerical simulations, the deformation failure behaviours of the SSCC arch centering are eventually obtained. The laboratory experimental results show that the maximum deformation appears near the spandrel of the arch centering and the ultimate bearing capacity is 1286.9kN. An SSCC and a U-shaped arch centerings have been simultaneously used in the supporting system of the gallery in Zhaolou coal mine project, and the monitoring results (after 157 days) show that their average displacement of the SSCC arch centering is 10.33 mm, which is only 18.3% of that obtained in the U36 arch centering. The above research results indicate that this kind of SSCC arch centering supporting system could efficiently control the deformation of the surrounding rock mass in mining galleries.

Borehole Radar for Delineation of Unapproachable Underground Coal-Mine Galleries below Grand Chord Railway Lines

There are chances of railway lines being unsafe and thus directly affecting the safety of persons and goods due to the presence of old, abandoned and inaccessible mine workings below them. In the past, about 21 galleries in the leasehold of Kunstoria and Satgram areas of the Eastern Coalfields Limited (ECL), West Bengal and 33 galleries in the leasehold of Mugma area of ECL were driven below the Eastern Railway on the Grand Chord Howrah-Delhi railway line between Andal and Dhanbad. The abandoned mine plans of most of these galleries are not available and as such the exact locations of the galleries were not known. Keeping the above points in view, the present study was taken up for delineating the inaccessible and unknown mine galleries using borehole radar near Ratibati Colliery, Satgram area. A borehole radar survey has been conducted using an antenna frequency of 100 MHz along the six proposed railway sites. Six mine galleries were delineated in a radial distance varying from 4.5 to 5.0 m from the investigation boreholes and at the depths of 24, 27.5, 36.5, 51.5, 53.5 and 54.5 m respectively, from the surface. These mine galleries have been confirmed using direct non-coring drilling. It is also suggested that all mine galleries should be filled up with sand for the safety of the Grand Chord railway tracks in future.

Supergene Alteration of Ore Deposits: From Nature to Humans

Supergene minerals form under near-ambient conditions on the Earth9s surface. Supergene mineralization is controlled by the parent rock composition, climatic conditions, geomorphological environment, and chemical compounds added during mineral processing. They appear in alteration zones called “orecretes.” Bronze Age miners exploited these easily accessible high-grade soft ores for Fe, Cu, Pb, and Ag. Some supergene minerals can also grow in poorly ventilated mining galleries and shafts, coat metal mining artifacts and smelting residues, and form from disastrous blasts and fires in ancient mining settlements. Supergene deposits bridge the gap between humans and metal resources at the interface between rock, soil, air, water, and living organisms. These deposits provide essential clues to geological, environmental, and archeological studies.

A Very Slow Creep Test on an Avery Island Salt Sample

The applied deviatoric stress during most creep tests performed on salt samples is in the 3.5–20 MPa range. However, the stresses actually experienced in the vicinity of a salt cavern are much smaller. Any extrapolation is difficult to vindicate, as the dominant micro-mechanisms are strongly suspected to be very different in the low-stress and medium-stress domains. To answer this concern, a very slow creep test was performed on an Avery Island salt sample. To minimize the influence of even the smallest of temperature deviations during the test, the testing apparatus was placed in a remote gallery of the Varangeville salt mine, taking advantage of the very stable temperature conditions offered in an underground environment. The test was performed in multiple stages and lasted 42 months. The successive loads of 0.1, 0.2, 0.3, and 0.5 MPa were applied. Measured steady-state strain rates were of the order of 10−12 s−1, which are significantly faster than that extrapolated from creep tests performed at loads ranging between 3.5 and 20 MPa.

Resistivity imaging technique to investigate the subsurface strata conditions due to blasting in underground coal mines in India

ABSTRACTProduction from underground coal mining in India has been decreasing since the last three decades. Blasting‐off‐the‐solid, in Indian underground mines, has been a widely practised method for winning coal while developing mine galleries in bord and pillar system. The blast holes are drilled in solid coal without free face in blasting‐off‐the‐solid method of mining and are blasted with permitted types of explosives and delay detonators. Blasting‐off‐the‐solid will play an important role in underground coal production. The mines that were planned earlier to be away from residential areas are now approaching to those areas. The coal reserves are being exploited very fast, and mine owners cannot ignore to take the coal beneath the structures/houses. In this paper, resistivity imaging technique has been used to document the change of subsurface structures/features between the surface and underground face, where blasting is carried out to extract the coal in underground coal mines. Resistivity imaging survey conducted at three mining sites revealed that there was no significant change in subsurface strata conducted during pre‐ and post‐blasting conditions. The slight change in resistivity values up to 35 Ωm up to a few metres of peripheral area of the blasting face in the mine may be either due to the effect of blast vibration and/or same void created by blasting or increase in porosity of overlying subsurface strata.

Metaturbidite-hosted gold deposits, Córrego do Sítio lineament, Quadrilátero Ferrífero, Brazil

A study of geology and rocks paragenesis has been conducted at the Córrego do Sítio auriferous lineament, containing the Cachorro Bravo, Laranjeiras and Carvoaria metaturbidite-hosted lode-gold deposits located in the Quadrilátero Ferrífero Region, Minas Gerais, Brazil. These representative deposits are described to illustrate the essentially similar general character of all the deposits of lineament as well as the wide compositional and mineralogical differences in the ore of the different deposits, where, for the Cachorro Bravo deposit, a geological mapping included two underground mine galleries. The Córrego do Sítio unit is a metamorphosed turbidite in an alternating sequence of metagraywackes and phyllites, with parallel to discordant metamafic dikes and sills. The ore zone is predominantly hosted at the stratigraphic break between metasedimentary and metamafic rocks. Four deformation events affected the mine sequence. Mineralized veins and veinlets are considered to have formed within a brittle-ductile shear-zone environment and occurred in multiple episodes. Different vein types are recognized, but the most important volumetrically is a S1-concordant type characterized by smoky and milky quartz-carbonate-sulfide ± sulfosalts veins. Veins are dominated by quartz, but locally they are characterized by carbonate and a large variety of sulfide and sulfosalt minerals. Pyrite is the commonest associated sulfide mineral, followed by arsenopyrite and pyrrhotite. An extensive mineralogical study of polished sections has confirmed different generations of sulfide minerals. The sulfides and sulfosalt minerals are interrelated in the veins and disseminated on wall rocks. The data are consistent with a genetic models related to other Archean lode-gold deposits.

Novel wireless channels characterization model for underground mines

The propagation characteristics of electromagnetic waves in underground mines are different from those in free space because of the harsh underground environment. Physical phenomena like severe reflection, scattering, and diffraction along the mines’ rough walls will affect the propagation of electromagnetic waves. Channel predictions are crucial for reliable and optimal wireless communication in an underground environment. Although there are several channel prediction techniques, most of them are very difficult and time consuming. This work presents a new approach in wireless channel modeling in underground mines. The model is generated by adopting a performance-based approach rather than classical coverage-based approach. This new model, called “Mine Segmenting Wireless Channel Model”, divides the mine area into three main segments: (1) Line-of-Sight (LOS), (2) Partial-Line-Of-Sight (PLOS) and (3) Non-Line-Of-Sight (NLOS). We examine the impact of topology on performance of 802.11b system with Rician/Rayleigh fading.The model is statistically verified using simulations and is applied to fading wireless local area networks channel for IEEE 802.11 applications. Finally, the communication performance of a realistic IEEE 802.11b signal is evaluated in a real underground mine gallery (NORCAT Mine, Sudbury, Ontario, Canada). The results of the actual experiment were very similar to that of the model simulation.

Geochemical Control of Acid Mine Drainage in Abandoned Mines: The Case of Ermioni Mine, Greece

Acid mine drainage is an extensively documented environmental issue, commonly originated by the weathering of sulfide ores both in active and abandoned mining sites. Even though national and international regulations obliged mining companies to handle this problem in active mines, in the abandoned ones it is usually regarded as a major environmental thread. Natural attenuation is a term that is used to describe a combination of in situ physical, chemical and biological processes that under some specific conditions, act without human interventions in order to reduce the mass, toxicity, mobility and concentration of metals in soil or groundwater” (USEPA, 1999). For those processes, the local lithology may plays a key role, when contributing to an alkaline environment, consequent the precipitation of metals in the form of hydroxides. Despite of the fact that in Ermioni, Greece, a mixed sulfide ore mine had been operational since 1928, it has been abandoned after 1978 and no restoration actions have been implemented. Dispersed ore tailings have been deposited near the galleries, being exposed to atmospheric conditions. Soil and mine-water samples were collected from the region of that abandoned mine. The soil was collected from tailings at superficial points near the mining galleries, while water was sampled from canals, which drain from the mining galleries to the nearby Roros River. The mineralogical composition of the soil samples was studied by X-ray Diffraction Spectroscopy and Scanning Electron Microscopy, while Flame Atomic Adsorption Spectroscopy was applied for the determination of the Fe, Zn, Cd, Cu, Pb, Mn, Ni, Co, Cr and Hg concentrations in the water samples.