scholarly journals Analysis of the Surface Subsidence Induced by Mining Near-Surface Thick Lead-Zinc Deposit Based on Numerical Simulation

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 717
Author(s):  
Yifan Zhao ◽  
Xingdong Zhao ◽  
Jiajia Dai ◽  
Wenlong Yu
Keyword(s):  
Large Scale ◽  
Surface Subsidence ◽  
Ecological Benefits ◽  
Near Surface ◽  
Economic Operation ◽  
Lead Zinc ◽  
Zinc Mine ◽  
Scale Surface ◽  
Good Agreement

This paper describes a case study of surface subsidence in the Hongling Lead-Zinc Mine. Hongling Lead-Zinc Mine is located in Inner Mongolia, China, about 240 km away from the border between China and Mongolia. There is a batch of outcrops of the near-surface thick steep-dip metamorphic orebody. The large-scale surface subsidence induced by underground excavation has brought some impact on the safety of herdsmen and their daily husbandry activities nearby. The requirements of reclamation for subsidence areas in the relevant laws and regulations, raise enormous pressure and risk on safe and economic operation. In this paper, a 3D numerical model of this mine was built by 3DMine and FLAC3D to analyse the excavation procedure and mechanism. The results of the simulation were in good agreement with the field subsidence data collected by satellites and unmanned aerial vehicles from 2009 to 2019. The analysis showed that the current mining method—an integrated underground method of stoping and caving—accelerated the surface subsidence, and some measures of monitoring, controlling and management were expected to take in order to improve economic and ecological benefits.

CME arrival time predictions with a deformable front

2021 ◽  
Author(s):  
Jürgen Hinterreiter ◽  
Tanja Amerstorfer ◽  
Martin A. Reiss ◽  
Andreas J. Weiss ◽  
Christian Möstl ◽  
...  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Arrival Time ◽  
Interplanetary Space ◽  
Solar Wind Speed ◽  
Model Combination ◽  
First Results ◽  
Good Agreement ◽  
Ambient Solar Wind

<p>We present the first results of our newly developed CME arrival prediction model, which allows the CME front to deform and adapt to the changing solar wind conditions. Our model is based on ELEvoHI and makes use of the WSA/HUX (Wang-Sheeley-Arge/Heliospheric Upwind eXtrapolation) model combination, which computes large-scale ambient solar wind conditions in the interplanetary space. With an estimate of the solar wind speed and density, we are able to account for the drag exerted on different parts of the CME front. Initially, our model relies on heliospheric imager observations to confine an elliptical CME front and to obtain an initial speed and drag parameter for the CME. After a certain distance, each point of the CME front is propagating based on the conditions in the heliosphere. In this case study, we compare our results to previous arrival time predictions using ELEvoHI with a rigid CME front. We find that the actual arrival time at Earth and the arrival time predicted by the new model are in very good agreement.</p>

scholarly journals A Theoretical Model for the Rake Blockage Mitigation in Deep Cone Thickener: A Case Study of Lead-Zinc Mine in China

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Zhuen Ruan ◽  
Yong Wang ◽  
Aixiang Wu ◽  
Shenghua Yin ◽  
Fei Jin
Keyword(s):  
Coarse Particles ◽  
Cemented Paste Backfill ◽  
Preventive Action ◽  
Unclassified Tailings ◽  
Paste Backfill ◽  
Lead Zinc ◽  
Zinc Mine ◽  
Deep Cone Thickener ◽  
Thickened Tailings

Deep cone thickener (DCT) is key equipment in cemented paste backfill (CPB) technology. However, rake blockage occurs frequently in DCT during the dewatering process of the unclassified tailings being thickened from dilute slurry to thickened tailings or paste. Rake blockage has disastrous effects on the CPB operation. In order to investigate the influencing factors of rake blockage in DCT, a mathematical model of rake power in DCT was developed. In addition, stacking mud bed (made of thickened tailings) from the DCT in Huize lead-zinc mine (HLZM) in different rake blockage accidents was sampled and tested to investigate the effect of tailings characters on rake blockage. Results indicated that the concentration of the mud bed and the friction between the mud bed and the cone wall contributed to the rake blockage. The concentration and friction were influenced by the high content of coarse particles in the mud bed. Moreover, activating devices for bed mud, as the corrective and preventive action, were developed to prevent the rake blockage, which was valid in HLZM.

scholarly journals The Implementation of a Mineral Dust Wet Deposition Scheme in the GOCART-AFWA Module of the WRF Model

2018 ◽  
Vol 10 (10) ◽  
pp. 1595 ◽  
Author(s):  
Konstantinos Tsarpalis ◽  
Anastasios Papadopoulos ◽  
Nikolaos Mihalopoulos ◽  
Christos Spyrou ◽  
Silas Michaelides ◽  
...  
Keyword(s):  
Wet Deposition ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Wrf Model ◽  
Saharan Dust ◽  
Near Surface ◽  
Dust Transport ◽  
Wet Scavenging ◽  
Aerosol Module

The principal objective of this study is to present and evaluate an advanced dust wet deposition scheme in the Weather and Research Forecasting model coupled with Chemistry (WRF-Chem). As far as the chemistry component is concerned, the Georgia Tech Goddard Global Ozone Chemistry Aerosol Radiation and Transport of the Air Force Weather Agency (GOCART-AFWA) module is applied, as it supports a binary scheme for dust emissions and transport. However, the GOCART-AFWA aerosol module does not incorporate a wet scavenging scheme, nor does it interact with cloud processes. The integration of a dust wet deposition scheme following Seinfeld and Pandis into the WRF-Chem model is assessed through a case study of large-scale Saharan dust transport over the Eastern Mediterranean that is characterized by severe wet deposition over Greece. An acceptable agreement was found between the calculated and measured near surface PM10 concentrations, as well as when model estimated atmospheric optical depth (AOD) was validated against the AERONET measurements, indicating the validity of our dust wet deposition scheme.

Estimating Near-Surface Rigidity from Low-Frequency Noise Using Collocated Pressure and Horizontal Seismic Data

2020 ◽  
Vol 110 (4) ◽  
pp. 1960-1970
Author(s):  
Jiong Wang ◽  
Toshiro Tanimoto
Keyword(s):  
Large Scale ◽  
Elastic Structure ◽  
Frequency Noise ◽  
Seismic Signals ◽  
Measured Velocity ◽  
Near Surface ◽  
Vertical Excitation ◽  
Single Station ◽  
Surface Rigidity ◽  
Scale Surface

ABSTRACT We propose a single-station approach to estimate near-surface elastic structure using collocated pressure and seismic instruments. Our main result in this study is near-surface rigidity (shear modulus) structure at 784 EarthScope Transportable Array (TA) stations in operation from mid-2011 to the end of 2018 using coherent horizontal seismic and pressure signals at 0.02 Hz. We isolate time periods for which surface pressure change is the dominant excitation source for seismic signals by searching for data windows with large pressure variations and high-seismic-pressure coherence. We emphasize the importance of using horizontal seismic components for two reasons: first, horizontal seismic signals are significantly higher than vertical signals at 0.02 Hz due to ground tilt, and second, we can analytically compute the predicted horizontal signals without an assumption of atmospheric pressure wavespeed (which is required for predicting the vertical excitation). Sensitivity kernels from 0.01 to 0.05 Hz show that this pressure–seismic coupling is mostly dependent on rigidity shallower than 50 or 100 m. Our estimates of shallow elastic structure show good spatial agreement with large-scale surface geological features. For instance, stations in the Appalachian Mountains mostly have high rigidity, whereas low-rigidity sites dominate the Mississippi Alluvial Plain. Because of the lack of measured velocity profiles, we quantitatively validate our approach by comparing with VS30 models that are based on proxies such as topographic slopes and large-scale surface geology. We estimate near-surface rigidity at 784 TA stations, where these locations have no prior structure information. Our method provides independent information for seismic hazard studies.

Vein, manto, and chimney mineralization at the Fresnillo sliver–lead–zinc mine, Mexico

1986 ◽  
Vol 23 (10) ◽  
pp. 1603-1614 ◽  
Author(s):  
A. James Macdonald ◽  
Marek J. Kreczmer ◽  
Stephen E. Kesler
Keyword(s):  
Hydrothermal Activity ◽  
Partial Replacement ◽  
Isotopic Ratios ◽  
Near Surface ◽  
Northern Mexico ◽  
Quartz Monzonite ◽  
Lead Zinc ◽  
Zinc Mine ◽  
Lead Isotopic Ratios ◽  
Ore Zones

Discovered in 1553, the Fresnillo mine in central Mexico has produced approximately 18 t Au, 8830 t Ag, 690 000 t Pb, 925 600 t Zn, and 74 000 t Cu (data for production from 1921 to 1984 inclusive). Ore has been mined from an oxide capping near surface and from unoxidized veins, mantos, and chimneys to a depth of 1 km along a strike length of 4 km. Ore zones at depth, in the northwest portion of the mine, are spatially related to a quartz monzonite porphyry stock, which intrudes a sequence of Mesozoic marine sediments that is overlain by terrestrial rhyolites. Manto and chimney mineralization followed development of skarn around the intrusion and was cut, in turn, by the veins that contain the bulk of the ore. The veins cut the quartz monzonite stock. Manto and chimney mineralization is characterized by partial replacement of the Mesozoic sedimentary rocks with axinite, hedenbergite, quartz, carbonate, sulphides, sulphosalts, sulpharsenides, and sulphantimonides. Brecciation preceded replacement in the chimney bodies. One of the largest replacement orebodies, the Cueva Santa Branch Manto in the central part of the mine, contains an orthogonal fracture set formed during antiformal folding. Trends in grade distribution throughout the manto follow the orthogonal fractures, which are filled by quartz and sulphides. Silver/base-metal ratios show marked peaks where manto mineralization abuts against major veins. Fluid-inclusion filling temperatures and salinities are high in ore zones adjacent to the quartz monzonite stock at a depth of 1 km: mean filling temperature is approximately 320 °C (range 230–370 °C), salinity ranges from 4 to 12 eq. wt.% NaCl. Fluid inclusions from ore near surface exhibit lower filling temperatures (a mean of 235 °C and a range of 210–290 °C) and lower salinity (< 1 eq. wt.% NaCl). The data are consistent with a reduction in temperature and with dilution as the hydrothermal fluids flowed away from the intrusive porphyry.δ34S values for sphalerite, galena, and chalcopyrite from deeper and intermediate levels in the mine range from −6.1 to −3.5‰. Calculated δ34SΣS is approximately 0‰, suggesting a magmatic sulphur source. Lead isotopic ratios obtained from galena-bearing vein, manto, and chimney samples throughout the mine fall on a line defined by 34 deposits in northern Mexico with slope of 0.092 ± 0.017 in the 208Pb/204Pb versus 207Pb/204Pb system. The lead data indicate that felsic igneous processes extracted the metal from a Precambrian basement source; this was followed by concentration within mineralized zones during hydrothermal activity.

Numerical Investigation on Safe Mining of Residual Pillar in Goaf: A Case Study of Panlong Lead–Zinc Mine

2020 ◽  
Vol 38 (4) ◽  
pp. 4269-4287 ◽  
Author(s):  
Feifei Wang ◽  
Qingyang Ren ◽  
Bin Chen ◽  
Ping Zou ◽  
Zijian Peng ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Lead Zinc ◽  
Zinc Mine ◽  
Safe Mining

scholarly journals Integrating weather and geotechnical monitoring data for assessing the stability of large scale surface mining operations

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
Chrysanthos Steiakakis ◽  
Zacharias Agioutantis ◽  
Evangelia Apostolou ◽  
Georgia Papavgeri ◽  
Achilles Tripolitsiotis
Keyword(s):  
Data Management ◽  
Large Scale ◽  
Surface Mining ◽  
Monitoring Data ◽  
Data Management System ◽  
Series Data ◽  
Mining Operations ◽  
Adverse Weather ◽  
Scale Surface

AbstractThe geotechnical challenges for safe slope design in large scale surface mining operations are enormous. Sometimes one degree of slope inclination can significantly reduce the overburden to ore ratio and therefore dramatically improve the economics of the operation, while large scale slope failures may have a significant impact on human lives. Furthermore, adverse weather conditions, such as high precipitation rates, may unfavorably affect the already delicate balance between operations and safety. Geotechnical, weather and production parameters should be systematically monitored and evaluated in order to safely operate such pits. Appropriate data management, processing and storage are critical to ensure timely and informed decisions.This paper presents an integrated data management system which was developed over a number of years as well as the advantages through a specific application. The presented case study illustrates how the high production slopes of a mine that exceed depths of 100–120 m were successfully mined with an average displacement rate of 10– 20 mm/day, approaching an almost slow to moderate landslide velocity. Monitoring data of the past four years are included in the database and can be analyzed to produce valuable results. Time-series data correlations of movements, precipitation records, etc. are evaluated and presented in this case study. The results can be used to successfully manage mine operations and ensure the safety of the mine and the workforce.

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.

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