scholarly journals Peculiarities of the underground mining of high-grade iron ores in anomalous geological conditions

2019 ◽  
Vol 28 (4) ◽  
pp. 706-716
Author(s):  
Mykhailo V. Petlovanyi ◽  
Vladislav V. Ruskykh
Keyword(s):  
Iron Content ◽  
Underground Mining ◽  
Hanging Wall ◽  
Slope Angle ◽  
High Grade ◽  
Ore Deposit ◽  
Ore Body ◽  
Subsequent Decrease ◽  
Geological Conditions ◽  
The Difference

This paper is dedicated to research into the geological peculiarities, shape of the ore body and the occurrence of the host rocks in the hanging wall of the Pivdenno-Biloz- erske deposit , as well as their influence on the degrees and quality of high-grade iron ore extraction. It is noted that in the interval of 480 – 840 m depths, a decrease is observed in the stability of the natural and technogenic massif, which is caused by the increase in rock pressure with depth, the influence of blast- ing operations on the massif and the difference in geological conditions. This has led to the collapse of hanging wall rocks and backfill into the mined-out space of chambers in certain areas of the deposit, the dilution of the ore and deterioration of the operational state of the underground mine workings. Attention is focused on the causes and peculiarities of consequences of the collapse of the hanging wall rocks during ore mining, which reduce the technical and-economic indexes of the ore extraction from the chambers. A 3D-model of an ore deposit with complex structural framework has been developed, which makes it possible to visually observe in axonometric projection the geological peculiarities and the shape of the ore body. The parameters have been studied of mining chambers in the 640 – 740 m floor under different changing geological conditions of the ore deposit and hanging wall rocks occurrence – the northern, central and southern parts. The difference in the iron content in the mined ore relative to the initial iron content in the massif has been defined as an indicative criterion of the influence of changing conditions on the production quality. The reasons have been revealed which contribute to the collapse of the rocks and the subsequent decrease in the iron content of the mined ore in ore deposit areas dif- fering by their characteristics. It has been determined that within the central and half of the southern ore deposit parts with a length of 600 m, an anomalous geological zone is formed, the manifestation of which will be increased with the depth of mining. It was noted that within this zone, with the highest intensity and density of collapse of hanging wall rocks, the influence of decrease in the slope angle and change in the strike direction are of greatest priority, and such geological factors as a decrease in hardness, rock morphology, deposit thickness increase this influence significantly. To solve the problems of the hanging wall rocks’ stability, it is recommended to study the nature and direction of action of gravity forces on the stope chambers in the northern, central and southern parts, as well to search for scientific solutions in regard to changes in the geometric shapes of stope chambers and their spatial location, improving the order of reserves mining in terms of the ore deposit area, the rational order of breaking-out ore reserves in the chambers with changing mining and geological conditions of the fields’ development.

Exploration geochemistry of surficial media over the high-grade McArthur River uranium deposit, Saskatchewan, Canada

2021 ◽  
Vol 59 (5) ◽  
pp. 913-945
Author(s):  
Steve R. Beyer ◽  
Kurt Kyser ◽  
Tom G. Kotzer ◽  
Kevin Ansdell ◽  
David Quirt
Keyword(s):  
Pinus Banksiana ◽  
Hanging Wall ◽  
Coarse Fraction ◽  
Mining Activity ◽  
Alteration Zone ◽  
High Grade ◽  
Soil Geochemistry ◽  
Mine Site ◽  
Ore Body ◽  
Mine Effluent

ABSTRACT An orientation survey using surficial media was performed over the high-grade McArthur River unconformity-related U deposit (Saskatchewan, Canada) to test whether or not secondary dispersion of elements related to the ore body or alteration zone can be detected at the surface more than 500 m above the deposit. Organic-rich Ah-horizon soils, Fe-rich B-horizon soils, C-horizon soils, tree cores of Jack pine (Pinus banksiana), and glacially dispersed boulders of Manitou Falls Formation sandstone that host the U deposit were collected in four sampling grids near the mine site. Two of the grids overlaid the trace of the P2 fault that hosts the deposit and extends nearly to the surface, one grid overlaid both the P2 fault and one of the high-grade ore bodies (Zone 4), and one grid was located 2.5 km away from the ore body surface trace in the barren hanging wall of the P2 fault. The grid overlying the Zone 4 ore body had the highest proportion of samples with elevated U and low 207Pb/206Pb ratios, the latter indicative of radiogenic Pb from a high-U source, measured in two size fractions of Ah-horizon soils using Na pyrophosphate leach, pine tree cores using total digestion, and sandstone boulders using 2% HNO3 leach. A handful of pathfinder elements, such as As, Co, Ni, and Pb, are variably associated with the U and radiogenic Pb. Sandstone boulders with an assemblage of dravite + kaolinite ± illite, determined using shortwave infrared (SWIR) spectroscopy and matching the alteration mineralogy in the Manitou Falls Formation above the U deposit, were prevalent in the grid above the Zone 4 ore body and in the adjacent grid in the direction of glacial dispersion. A coarse fraction of the B-horizon soils, leached with 5% HNO3, highlighted the grid above the Zone 4 ore body to a lesser extent, whereas HNO3 leaches and aqua regia digests of C-horizon soil separates did not highlight the P2 fault or ore body trace due to influence by parent till mineralogy. Results of environmental monitoring at the mine site, which was active at the time of sampling, suggest that dust containing U, Pb, and radionuclides from waste rock piles and a ventilation shaft could influence A-horizon soil geochemistry near the mine site, and that U and radiogenic Pb anomalies in B- and C-horizon soils near the water table are close to a treated mine effluent discharge point. However, older trees that record elevated U and radiogenic Pb in annual rings that pre-date mining activity, and alteration mineralogy and geochemistry of boulders that are less susceptible to the influences of mining activity, add confidence that the geochemical anomaly in diverse surficial media above the Zone 4 ore body represents secondary dispersion from the underlying U deposit.

Hierarchical fuzzy-AHP-based multi-criteria decision making approach for selection of underground metal mining method

2021 ◽  
Vol 15 (3) ◽  
pp. 405-420
Author(s):  
Bhanu Chander Balusa ◽  
Amit Kumar Gorai
Keyword(s):  
Decision Making ◽  
Underground Mining ◽  
Fuzzy Ahp ◽  
Hanging Wall ◽  
Ore Deposits ◽  
Mining Method ◽  
Metal Mining ◽  
Extrinsic Factors ◽  
Ore Deposit ◽  
Mining Methods

In the last few decades, many underground mining methods were proposed for extractions of ores. The decision-making for selecting the most suitable mining method for a typical ore depost depnds on various intrinsic and extrinsic factors (intrinsic – dip, shape, thickness, depth, grade distribution, RMR (rock mass rating) and RSS (rock substance strength) of ore, hanging wall, footwall, and extrinsic – recovery, dilution, safety, productivity, flexibility, capital). The present study aims to develop a hierarchical Fuzzy-AHP (FAHP) model for choosing the most suitable underground mining method for an ore deposit. The structure of the proposed hierarchical FAHP model consists of five levels. The level-1 of the hierarchy defines two variables (intrinsic factors and extrinsic factors). These are further classified into quantitative or qualitative nature of variable (listed in level-2). The criteria, sub-criteria, and mining method variables are listed respectively in Level 3, Level 4, and Level 5. For each level of the hierarchy, a fuzzy pair-wise comparison matrices are developed using the corresponding levels’ listed variables. These matrices at each level are subsequently used to determine the local and global weights of each variable. The global weights are used for prioritizing the different mining methods. The proposed hierarchical FAHP model was validated by considering the field data of two different ore deposits in India. The results showed that the most appropriate mining method predicted from the decision-making model and the adopted mining method for extracting the ore deposit are same in two case studied mines.

scholarly journals A New Mining Scheme for Hanging-Wall Ore-Body during the Transition from Open Pit to Underground Mining: A Numerical Study

2018 ◽  
Vol 2018 ◽  
pp. 1-17
Author(s):  
Baohui Tan ◽  
Fengyu Ren ◽  
Youjun Ning ◽  
Rongxing He ◽  
Qiang Zhu
Keyword(s):  
Underground Mining ◽  
Numerical Study ◽  
Hanging Wall ◽  
Slope Instability ◽  
Open Pit ◽  
Ore Body ◽  
Instability Development ◽  
Induced Caving ◽  
Iron Mine ◽  
Mining Scheme

A new mining scheme by employing the induced caving mining method to exploit hanging-wall ore-body during the transition from open pit to underground mining is proposed. The basic idea is to use the mined-out area generated by the planned mining of the hanging-wall ore-body to absorb the collapsed slope body, so as to avoid the influence of the inner-slope mining to the normal open-pit mining and guarantee mining efficiency during the transition stage. Numerical simulation study on the process of induced caving mining of hanging-wall ore-body is carried out based on the practical engineering setting of the Hainan iron mine, China, by employing the numerical method of discontinuous deformation analysis (DDA). The impact of rock mass structure on the mechanism of slope instability development and the mining hazard assessment in the new mining scheme is investigated. The influence of mining sequence on slope instability development and mining safety is also analyzed by taking the hanging-wall ore-body mining under the southern anti-dip slope at the Hainan iron mine as an example, and eventually a reliable mining scheme via induced caving is obtained. The numerical study proves the feasibility of the proposed new mining scheme for hanging-wall ore-body and provides theoretical and technical support for its application in practical mining activities.

scholarly journals Instability Assessment of Hanging Wall Rocks during Underground Mining of Iron Ores

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 858
Author(s):  
Oleg Bazaluk ◽  
Mykhailo Petlovanyi ◽  
Serhii Zubko ◽  
Vasyl Lozynskyi ◽  
Kateryna Sai
Keyword(s):  
Physical Modeling ◽  
Underground Mining ◽  
Hanging Wall ◽  
Geological Structure ◽  
Ore Deposit ◽  
Source Data ◽  
Deformation Processes ◽  
Rock Deformations ◽  
Sloping Bottom

The paper presents the study of the deformation processes development in unstable rocks of the hanging wall during mining a thick steeply dipping ore deposit in the example of the Yuzhno-Belozerskyi deposit. In the studied field, there are problems of stability of hanging wall rocks, represented by low-resistant shale rocks that do not withstand significant outcrops in time. A decrease in stability is manifested in the form of failure of the hanging wall rocks into the stope. Based on a detailed study of the ore deposit geological structure and the performance of the stopes mining, according to the survey data, an area of the deposit has been identified where the ore failure and dilution reach 4%–8% with a maximum value of 12%. This also makes it possible to determine the most important averaged source data for performing physical modeling on equivalent materials. It has been determined that the deformation value of the hanging wall rocks with subsequent failure into the stope and ore mass deformation in the sloping bottom change exponentially with an increase in the depth of the stope location, and the dynamics of increasing rock deformations in the hanging wall is noticeably higher than in the sloping bottom of the stope. This reduces the quality of the mined ore and increases the probability of rock failure area propagation to the hanging wall drifts with their subsequent destruction. The results of physical modeling are characterised by acceptable reliability and are confirmed by a high similarity with the actual data on ore dilution with broken rocks during the stopes development. It has been found that during the formation of a steeply dipping outcrop of stopes with an area of 1200 m2, unstable rocks of the hanging wall are prone to failure of significant volumes. For successful mining and achieving stope element stability, it is recommended to optimise its parameters, the height, width and the value of a steeply dipping outcrop, as well as to preserve the ore pillar in the hanging wall until the ore is broken and drawn from the rest of the stope.

scholarly journals Ground Pressure under Mining Ore Bodies of Different Angles Based on Physical Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiaoshuang Li ◽  
Jian Song
Keyword(s):  
Stress Distribution ◽  
Physical Simulation ◽  
Underground Mining ◽  
Similarity Theory ◽  
Vertical Direction ◽  
Overburden Rock ◽  
Rock Layer ◽  
Ground Pressure ◽  
Ore Body ◽  
Geological Conditions

Ground pressure characteristics of the ore body and the overburden deformation of the stope depend highly on the combined influence of geological conditions and mining disturbance. The ore body inclination, as a natural geological factor, has a nonnegligible effect on the underground mining. The ore angle plays a great role in the stress distribution of the overlying rock layer, resulting in the movement and destruction of the rock layer. The variation of the ore angle dominates the stress distribution of the overburden rock, the forms of movement, destruction, and the surface moving basin. Here, taking the geological mining conditions of the deep ore body mining in Jinning Phosphate Mine as the engineering background, we adopt a similar material ratio scheme of each rock layer in the mining area via the similarity theory and the principle of orthogonal experiment. We conduct systematic study on the strata movement, mining failure characteristics, and movement of the overlying rock in stope using a similar simulation test under two different ore angles of 20° and 50°. We found that, as the ore body inclination increases from 20° to 50°, the overburden unloading area of the stope extending to the deep part of the rock layer in the vertical direction is more obvious and its shape is more asymmetric about the stope center. The unloading area is more concentrated in the middle and upper part of the stope, while the upward development trend is more obvious. The relevant results can provide a certain reference for the underground mining of the mines and those with similar conditions.

scholarly journals Selective underground mining of complex structured ore bodies of Kryvyi Rih Iron Ore Basin

2018 ◽  
Vol 60 ◽  
pp. 00041 ◽  
Author(s):  
Vsevolod Kalinichenko ◽  
Serhii Pysmennyi ◽  
Nataliia Shvaher ◽  
Olena Kalinichenko
Keyword(s):  
Iron Content ◽  
Iron Ore ◽  
Underground Mining ◽  
Ore Deposits ◽  
Thickness Ratio ◽  
Operating Costs ◽  
Ore Body ◽  
Ore Bodies ◽  
Selective Mining ◽  
To Receive

Selective mining of complex structured ore bodies will enable increased iron content in the mined ore mass in underground mining at Kryvyi Rih iron ore basin applying the existing mining systems. The article determines the way the grade changes in a mine block of a complex structured ore body when applying bulk and selective mining as well as factors influencing indices of extracting ore mass from the block. The investigation results prove that it is reasonable to mine complex structured ore deposits with barren inclusions applying selective mining if the iron content in the block varies from 64 to 67% and horizontal thickness of the barren inclusion makes 4 – 12 m. At that, the thickness ratio should not exceed 0.3. Stoping methods should be applied to receive high indices of ore mass extraction. There is determined an ore/barren inclusion-to-ore body thickness ratio considering the dilution factor that confirms practicability of selective mining of complex structured ore bodies. Selective mining of complex structured ore deposits of Kryvyi Rih iron ore basin applying open stoping enables increasing the mined ore mass quality without considerable capital and operating costs and, consequently, staying on the market and enhancing the environmental situation in the region.

scholarly journals Numerical Simulation of Surface Subsidence and Backfill Material Movement Induced by Underground Mining

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xibing Li ◽  
Dongyi Wang ◽  
Chongjin Li ◽  
Zhixiang Liu
Keyword(s):  
Underground Mining ◽  
Hanging Wall ◽  
Ground Surface ◽  
Surface Subsidence ◽  
Mining Method ◽  
Backfill Material ◽  
Ore Body ◽  
Sublevel Caving ◽  
Lead Zinc ◽  
Zinc Mine

Surface subsidence induced by underground mining is one of the challenging problems in mining engineering, which can destroy ground surface buildings and cause huge economic losses to the mine. In this study, a two-dimensional numerical model, established by the discrete element method code PFC2D, was adopted to investigate the mechanical mechanism of surface subsidence and backfill material movement induced by underground mining in the Hongling lead-zinc mine. In the first simulation case, the ore body was excavated from the ground surface to the mining level 705 m by the sublevel caving mining method, and the stress evolution during the mining process was analyzed to reveal the mechanical mechanism of surface subsidence. In the second and third simulation cases, the mined-out areas above 905 m were backfilled by the noncemented tailings and an insulating pillar was reserved beneath the backfill material, and then the deep ore body was excavated by two different mining methods to study the movement law of the backfill material and rock strata induced by underground mining. The numerical simulation results show that when the sublevel caving mining method is adopted, underground mining can induce toppling failures in the hanging wall and lead to a large collapse pit in the ground surface. After the toppling failures in the hanging wall, the collapsed waste rock in the mined-out area can provide support force for the surrounding rock and restrict the further collapse of the hanging wall. Furthermore, when the cut-and-fill mining method is adopted for the excavation of deep ore body, the insulating pillar can restrict the horizontal displacement of surrounding rock and maintain the stability of the backfill material. The cut-and-fill mining method can efficiently control the surface subsidence and prevent the occurrence of collapse pit in the ground surface and is recommended for the Hongling lead-zinc mine to solve the surface subsidence problem.

scholarly journals Substantiation of process schemes of field development taking into account technogenic conversion

2021 ◽  
pp. 5-14
Author(s):  
Artur Mazhitov
Keyword(s):  
Economic Efficiency ◽  
Natural State ◽  
Ore Deposit ◽  
Sulfide Deposits ◽  
Field Development ◽  
Ore Body ◽  
Applied Development ◽  
Geological Conditions ◽  
Induced Changes ◽  
Type Sequence

Introduction. Mining disturbs the natural state of the rock mass. Besides, the field reserves are of a different degree and nature of man-induced changes, which directly affects mining prime cost and ore marketable value. The scientific and practical relevance of the research consists in ensuring increased completeness and economic efficiency of field development by applying the development systems of different classes and taking into account the man-induced changes in reserves in mining dynamics. Research aim is to substantiate the technological schemes of mining, that take into account the possibility and feasibility of developing the reserves which have been affected by the man-induced changes, in particular when switching from one class of development systems to another. Research methods. In this research, based on the analysis of the mining and geological conditions of copper sulfide deposits, economic and mathematical modeling of developing an ore deposit by development systems of different classes was carried out, and the man-induced changes in underground reserves in the process of mining were taken into account. Results. Based on the modeling results, it was found that the increase in the economic efficiency of the deposit development is provided by justifying the type, sequence, and limits of applying different geotechnologies related to different classes of development systems within the entire deposit and a separate ore body. Conclusion. The research results can be used when designing fields in terms of selecting and substantiating the applied development systems.

The iron content of iron superoxide dismutase: determination by anomalous scattering

1983 ◽  
Vol 218 (1210) ◽  
pp. 119-126 ◽  
Keyword(s):  
Superoxide Dismutase ◽  
Iron Content ◽  
Three Dimensional ◽  
Anomalous Scattering ◽  
Total Iron Content ◽  
Iron Site ◽  
Iron Superoxide Dismutase ◽  
Density Map ◽  
The Difference ◽  
Electron Density Map

The number of iron atoms in the dimeric iron-containing superoxide dismutase from Pseudomonas ovalis and their atomic positions have been determined directly from anomalous scattering measurements on crystals of the native enzyme. To resolve the long-standing question of the total amount of iron per molecule for this class of dismutase, the occupancy of each site was refined against the measured Bijvoet differences. The enzyme is a symmetrical dimer with one iron site in each subunit. The iron position is 9 ņ from the intersubunit interface. The total iron content of the dimer is 1.2±0.2 moles per mole of protein. This is divided between the subunits in the ratio 0.65:0.55; the difference between them is probably not significant. Since each subunit contains, on average, slightly more than half an iron atom we conclude that the normal state of this enzyme is two iron atoms per dimer but that some of the metal is lost during purification of the protein. Although the crystals are obviously a mixture of holo- and apo-enzymes, the 2.9 Å electron density map is uniformly clean, even at the iron site. We conclude that the three-dimensional structures of the iron-bound enzyme and the apoenzyme are identical.

scholarly journals Laboratory Study of Deformation Behaviour of Two New Reinforcing Polymeric TSLs and Their Potential Application in Deep Underground Coal Mine

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2205
Author(s):  
Han Liang ◽  
Jun Han ◽  
Chen Cao ◽  
Shuangwen Ma
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Underground Mining ◽  
Deformation Behaviour ◽  
Polymer Materials ◽  
Surface Protection ◽  
Steel Mesh ◽  
Geological Conditions ◽  
Deep Underground ◽  
Roadway Support

Thin spray-on liner (TSL) is a surface protection technology used by spraying a polymer film, which is widely used for mine airtightness and waterproofing. A reinforcing TSL can replace steel mesh, which is a new method for roadway support. This paper reviews the development of a reinforcing TSL. Considering the deterioration of geological conditions in deep underground mining and the demand for reinforcing automation, two kinds of polymeric reinforcing TSL (RPTSL) materials are developed. The mechanical characteristics of the new TSL materials are studied experimentally. Results show that the average compressive strength, tensile strength, cohesion, and internal friction angle of the two TSL materials are 52 and 32 MPa, 12 and 8 MPa, 6.2 and 17.2 MPa, and 33.6° and 25.9°, respectively. The bonding strength between the two materials and coal is greater than the tensile strength of coal itself, and the mechanical properties of the material for comparison are lower than those of both materials. Based on the TSL support mechanism, we examine the application of the two TSL materials to the mining environment and compare the mechanical properties of polymer materials and cement-based materials. The advantages of polymer materials include versatile mechanical properties, good adhesion, and high early strength. This study provides a new support material to replace steel mesh for roadway surface support, which satisfies the needs of different surface support designs under complex geological conditions, and promotes the automation of roadway support.

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