scholarly journals The Establishment of Ore-Controlling Fracture System of Baoginshan Gold Mine Based on Fracture-Tectonic Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yulong Lu ◽  
Xingqiang Li ◽  
Yang Liu ◽  
Jiahao Leng
Keyword(s):  
Shear Fracture ◽  
Shear Mode ◽  
Gold Mine ◽  
Fracture System ◽  
Principal Stresses ◽  
Secondary Fracture ◽  
The North ◽  
Ore Body ◽  
Type Fracture ◽  
P Type

The Baoginshan quartz vein type gold mine in the Baimashan-Longshan-Ziyunshan gold belt is the object of study, and the nature of the fracture structure and its ore-controlling effect are studied through surface and pit investigation, and the nature of the ore-controlling structure system and combination pattern of the Baoginshan gold mine is established. The F7 and F9 fractures in the near-east-west (EW) direction are the main fractures, which tend to the north and control the spreading of the ore zone; the northwest (NW) direction secondary tension fracture, with a dominant yield of 221°∠63°, is a T-type fracture in the Riedel shear mode and is the ore-holding structure of the vein-like ore body; the northeast-east (NEE) direction secondary shear fracture, with a dominant yield of 343°∠53°, is a P-type fracture and the combination of the two controls the specific positioning of the ore body. The characteristics and nature of the fracture structures in the whole ore zone, as well as their combination patterns, indicate that the overall ore-controlling fracture system of Baoginshan is a right-going tensional shear fracture zone composed of NW-oriented (T-type) and NEE-oriented (P-type) secondary fractures with F7 and F9 fractures as boundary fractures. The directions of the principal stresses are σ1≈158°∠40°, σ2≈288°∠38°, and σ3≈42°∠28°, respectively. In the next step of the prospecting process, based on increasing the spacing of prospecting pits (to 40m), in-pit drilling is deployed in the upper and lower discs of the NEE secondary fracture along with the tendency and strike for literacy, which can significantly improve the efficiency and effectiveness of prospecting and greatly reduce the cost of prospecting.

scholarly journals Rupture process of the 2014 Orkney earthquake, South Africa

2017 ◽  
Vol 17 (4B) ◽  
pp. 75-81
Author(s):  
Okubo Makoto ◽  
Artur Cichowicz ◽  
Hiroshi Ogasawara ◽  
Osamu Murakami ◽  
Shigeki Horiuchi
Keyword(s):  
South Africa ◽  
Strong Motion ◽  
Rupture Process ◽  
Gold Mine ◽  
Distribution Analysis ◽  
S Wave ◽  
Aftershock Distribution ◽  
North West ◽  
The North ◽  
Initial Rupture

An earthquake has occurred at 10:22:33 UT on 5 August 2014 in the Klerksdorp district, the North West province of South Africa. Its hypocenter is located beneath an Orkney town, where more than 10 gold mines exist. The Council for Geoscience (CGS) in South Africa reported that the magnitude and depth was ML5.5 and 4.7 km, respectively. CGS has been operating 17 surface seismic acceleration stations with 10 km interval in average, and obtained continuous acceleration seismograms through the time of the earthquake and following aftershocks. Using these seismograms, we analyzed the mainshock rupture process of this earthquake. Analyzing these seismograms, we found the ‘initial rupture’ with a Richter scale approximately 4 has occurred 0.3 sec before mainshock. Furthermore, by applying detailed aftershock distribution analysis, we found most of aftershocks occurred surrounding upper and southern part of mainshock rupture area, including initial rupture hypocenter. In order to understand detailed rupture process of this event, we surveyed for strong motion generating area (SMGA) of mainshock by applying Isochrones backprojection method (IBM) to the mainshock S wave waveforms. SMGA distribution seems to fill the vacant space of the aftershock distribution and initial rupture’s hypocenter. And we also found that a horizontal layered seismic vacancy exists between aftershocks with gold mine blastings. This fact implies mainshock rupture did not extent up to gold mine.

scholarly journals Prospecting Potential of the Yanjingou Gold Deposit in the East Kunlun Orogen, NW China: Evidence from Primary Halo Geochemistry and In Situ Pyrite Thermoelectricity

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1117
Author(s):  
Jinjian Wu ◽  
Qingdong Zeng ◽  
Zhanhao Wei ◽  
Hongrui Fan ◽  
Kuifeng Yang ◽  
...  
Keyword(s):  
Gold Mineralization ◽  
Rock Type ◽  
Geochemical Data ◽  
Ore Body ◽  
Detachment Rate ◽  
East Kunlun ◽  
Field Investigations ◽  
And Cluster Analysis ◽  
P Type

The Wulonggou Au district in the East Kunlun Orogen is one of the most important Au producing regions in China. The Yanjingou Au deposit occurs within a shear zone in the northeastern Wulonggou Au district. Based on detailed field investigations, geochemical data for the primary halo, and in situ thermoelectric data for pyrite, the following key results were obtained: (1) the Yanjingou Au deposit has the fractured-altered-rock type gold mineralization that is arsenopyrite-rich; (2) elemental correlations and cluster analysis show that Au and As are the most diagnostic elements; (3) geochemical data for the primary halo indicate the deposit is a shallow supra-ore halo ore body; and (4) in situ pyrite thermoelectric data show that the proportion of P-type pyrite is >80% and the detachment rate is 50%, which can be inferred that the location of the ore body is shallow. Based on our data, we present a mineralization prediction model for the ore body. The Yanjingou Au deposit has a good mineralization and high prospecting potential, with at least half of the ore body being concealed at depth, which has important scientific guiding significance for the breakthrough of prospecting and exploration.

scholarly journals Interaction of Natural and Technical Systems in the Subsoil Development Areas

2019 ◽  
Author(s):  
В.И. Голик ◽  
Х.Х. Кожиев ◽  
О.Г. Бурдзиева ◽  
С.А. Масленников
Keyword(s):  
Strain Gauge ◽  
Underground Mining ◽  
Economic Effect ◽  
The State ◽  
Economic Effects ◽  
Raw Material ◽  
The North ◽  
Ore Body ◽  
Technology Improvement ◽  
River Valleys

Деятельность горнодобывающей отрасли осуществляется с высокой степенью риска. Проблема управления состоянием массива особо актуальна в условиях горного региона с неработающими выработками, воронками провалов и отвалами пород и хвостов обогащения на террасных участках и в долинах рек. Она особо актуальна в условиях региона Северная Осетия с неработающими выработками, воронками провалов и отвалами пород и хвостов обогащения на террасных участках и в долинах рек. Увеличение глубины горных работ и объемов выемки сырья в сейсмически активных районах усиливают статическое и динамическое воздействие на геомеханические системы. Одним из способов исследования динамики напряжений в массиве являются измерения с помощью тензометрических датчиков. На одном из месторождений была оборудована замерная тензометрическая станция. Полученные эпюры напряжений вокруг выработки служили основанием для оценки поведения массива. Установлено, что изменение состояния крепи в зависимости от фазы развития очистных работ подчиняется закономерности. Пока рудное тело в пределах блока ведет себя как защемленная в висячем и лежачем боках балка, напряжения распределяются равномерно. После отрезки рудного тела со стороны висячего бока нагрузка на верхний элемент крепи со стороны очистных работ возрастает. Одним из направлений совершенствования технологий является использование феномена заклинивания дискретных пород, что нередко позволяет обеспечить возможность отработки месторождений с получением экологоэкономического эффекта при обеспечении безопасности горных работ. Эффективность использования породных конструкций складывается из экономии труда и материалов на управление состоянием скальных массивов при подземных работах. Оптимизация влияния напряжений в зоне взаимодействия очистных и подготовительных выработок уменьшает разубоживание руд породами и снижает опасность травмирования работающих отлаивающимися породами. При подземной разработке скальных сложноструктурных металлических месторождений в зоне взаимодействия горных выработок величина и знак напряжений во времени и пространстве может быть прогнозирована с достаточной для оперативного управления детализацией. Учет геомеханических факторов при отработке таких участков позволяет корректировать параметры разработки с получением экономического эффекта от повышения качества добываемых руд и уменьшения опасности для работающих. Mining activities are carried out with a high degree of risk. The problem of managing the state of the massif is especially relevant in the conditions of a mountainous region with idle workings, funnel dips and dumps of rocks and tailings in terraced areas and in river valleys. It is especially relevant in the conditions of the North Ossetia region with idle workings, funnel dips and dumps of rocks and tailings in terraced areas and in river valleys. An increase in the depth of mining and volumes of raw material excavation in seismically active areas reinforce the static and dynamic effects on geomechanical systems. One of the methods for studying the dynamics of stresses in an array is measurements using strain gauge sensors. At one of the fields, a metering strain gauge station was equipped. The obtained stress diagrams around the working served as the basis for assessing the behavior of the array. It was established that the change in the state of the lining, depending on the phase of development of the treatment works, is subject to regularities. While the ore body within the block behaves like a beam pinched in the hanging and lying sides, the stresses are distributed evenly. After segments of the ore body from the side of the hanging side, the load on the upper support element from the side of the treatment works increases. One of the areas of technology improvement is the use of the phenomenon of jamming of discrete rocks, which often allows you to provide the opportunity to develop deposits with environmental and economic effects while ensuring the safety of mining. The efficiency of using rock structures consists of saving labor and materials on managing the state of rock masses during underground work. Optimization of the effect of stresses in the zone of interaction between treatment and preparatory workings reduces ore dilution by rocks and reduces the risk of injury to workers using exfoliated rocks. In underground mining of rocky complex structural metal deposits in the interaction zone of mine workings, the magnitude and sign of stresses in time and space can be predicted with sufficient detail for operational control. Consideration of geomechanical factors when mining such sites allows you to adjust the development parameters to obtain the economic effect of improving the quality of ore mined and reducing the risk to workers.

scholarly journals Effect of Shaft Pillar Extraction on Stability of Main Shaft: A Case Study at Xincheng Gold Mine, China

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Xige Liu ◽  
Wancheng Zhu ◽  
Kai Guan ◽  
Hongxun Zhang
Keyword(s):  
Numerical Simulation ◽  
Orthogonal Experiment ◽  
In Situ Monitoring ◽  
Gold Mine ◽  
Main Shaft ◽  
Displacement Monitoring ◽  
Ore Body ◽  
Main Factors

Mining of ore body in the vicinity of a shaft has a significant influence on its stability. The in situ monitoring and numerical simulation are employed to analyze the effect of shaft pillar extraction at Xincheng Gold Mine. The XI# ore body is recently found around and beneath the shaft, and mining in this area may be detrimental to the shaft. Firstly, on the base of geological survey and in situ displacement monitoring, mechanical parameters of rock mass are obtained and the displacement around the shaft is measured. Secondly, the sensitivities of five main factors that may affect the shaft displacement are analyzed by means of orthogonal experiment according to the numerical simulation with FLAC3D. Finally, a numerical model is established according to the in situ condition; in order to forecast the shaft displacement induced by mining activities of XI# orebody, the Mining Priority Index (MPI) is put forward and used to select the optimal mining sequence. Based on the comparison between the numerical results with the monitoring data, it is determined that the ore within 100 m from the shaft is not suggested to be extracted until the last period of the shaft life.

The structure and geological development of the Erickson gold mine, Cassiar District, British Columbia, with implications for the origin of mother-lode-type gold deposits

1989 ◽  
Vol 26 (12) ◽  
pp. 2645-2660 ◽  
Author(s):  
P. G. Anderson ◽  
C. Jay Hodgson
Keyword(s):  
North America ◽  
Middle Jurassic ◽  
Shear Zones ◽  
High Heat ◽  
Gold Deposits ◽  
Crustal Thickening ◽  
Orthorhombic Symmetry ◽  
Low Grade ◽  
Gold Mine ◽  
The North

The Erickson gold mine is a typical gold quartz vein deposit. The veins are hosted by a thrust-imbricated, gently dipping, synformal allochthon of low-grade metamorphic, Devonian to Upper Triassic basalts, argillites, and peridotites of oceancrustal origin belonging to the Sylvester Group, part of the Slide Mountain assemblage. The Sylvester allochthon lies concordantly on Devonian miogeoclinal sedimentary rocks of the North American continental margin and was emplaced in the Middle Jurassic as a result of the collision of the Quesnel arc with North America. The veins in the mine are hosted mainly by a moderately dipping system of shear zones with approximately orthorhombic symmetry, indicating a triaxial bulk, inhomogeneous strain pattern superimposed on the earlier formed, gently dipping thrusts. Steeply dipping extension veinlets, rotation of schistosity, and downdip slickenlines indicate the maximum shortening axis was subvertical. The veins display complex superimposed ribbon and breccia textures, indicating incremental growth. Most of the gold occurs in association with tetrahedrite, sphalerite, and chalcopyrite in steeply dipping, late, grey quartz veinlets localized within and striking perpendicular to the main veins. The vein-forming event, dated at 130 Ma, appears to have been related to extension and high heat flow associated with the rise of the Omenica geanticline, in turn the result of crustal thickening caused by the collision of the amalgamated Quesnel arc – North America plate with Stikinia in the Middle Jurassic.

A Discussion on global tectonics in Proterozoic times - Tectonics of the North Atlantic Proterozoic dyke swarm

1976 ◽  
Vol 280 (1298) ◽  
pp. 529-539 ◽  
Keyword(s):  
North Atlantic ◽  
Shear Zones ◽  
Dyke Swarm ◽  
Fracture System ◽  
West Greenland ◽  
The North ◽  
Ductile Shear Zones ◽  
The North Atlantic ◽  
Lateral Displacements ◽  
Global Tectonics

The Proterozoic North Atlantic dyke swarm occurs in Scotland, East and West Greenland, and Labrador, over an area of at least 250000 km2, and includes two dominant dyke sets which in West Greenland strike NNE-SSW, and ESE-WNW. The intrusive relations of the two sets, and their association with ductile shear zones and other lateral displacements of country rocks, show the dykes to represent a conjugate swarm emplaced along shear fractures, rather than along tensional openings. The mechanical behaviour of the Proterozoic lithosphere is considered in the context of the regional fracture system.

scholarly journals Investigation into the Effect of RFSSW Parameters on Tensile Shear Fracture Load of 7075-T6 Alclad Aluminium Alloy Joints

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3397
Author(s):  
Andrzej Kubit ◽  
Tomasz Trzepieciński ◽  
Elżbieta Gadalińska ◽  
Ján Slota ◽  
Wojciech Bochnowski
Keyword(s):  
Aluminium Alloy ◽  
Shear Fracture ◽  
Load Capacity ◽  
Fracture Load ◽  
Tensile Fracture ◽  
Welding Parameters ◽  
Tensile Shear ◽  
Optimal Amount ◽  
Average Value ◽  
Type Fracture

The aim of the investigations was to determine the effect of parameters of refill friction stir spot welding (RFSSW) on the fracture load and failure mechanisms of the resulting joint. RFSSW joints were made in 7075-T6 Alclad aluminium alloy sheets using different welding parameters. The load capacity of joints was determined under tensile/shear loadings. Finite element-based numerical simulations of the joint-loading process were carried out, taking into account the variability of elasto-plastic properties of weld material through the joint cross-section. The influence of welding parameters on selected phenomena occurring during the destruction of the joint is presented. The considerations were supported by a fractographic analysis based on SEM images of fractures. It was found that there is a certain optimal amount of heat generated, which is necessary to produce the correct joint in terms of its load capacity. This value should not be exceeded, because it leads to weakening of the base material and thus to a reduction in the strength of the joint. Samples subjected to uniaxial tensile shear load showed three types of failure mode (tensile fracture, shear fracture, plug type fracture) depending on the tool rotational speed and duration of welding. Prediction of the fracture mode using FE-based numerical modelling was consistent with the experimental results. The samples that were damaged due to the tensile fracture of the lower sheet revealed a load capacity (LC) of 5.76 KN. The average value of LC for the shear fracture failure mechanism was 5.24 kN. The average value of the LC for plug-type fracture mode was 5.02 kN. It was found that there is an optimal amount of heat generated, which is necessary to produce the correct joint in terms of its LC. Excessive overheating of the joint leads to a weakening of the base metal and thus a reduction in the strength of the joint. Measurements of residual stresses along the axis specimens showed the presence of stresses with a certain constant value for the welded area on the side of the 1.6 mm thick plate.

Sign in / Sign up

Export Citation Format

Share Document