Mining

摘要： China has set the first batch of rare earth mining quota for 2022 at 100,800 tons, up about 20% compared with that in 2021, with the smelting & separation quota at 97,200 tons.Quotas for the first half of 2021 were set at 84,000 tons for mining and 81,000 tons for smelting & separation. An independent industrial analyst said that the 20% jump was mainly due to China’s surging demand for Nd Fe B magnets, amid the new energy push in China.

摘要： From 1952 to 2022,the University of Science and Technology Beijing(USTB)has gone through an incredible journey of 70 years.From its beginning as the Beijing Institute of Iron and Steel Technology,China’s first higher institute of mining and metallurgy disciplines,to its selection as one of China’s key universities of“Project 211”,and then as a national“Double First-Class”(the World First-Class University and First-Class Academic Discipline Construction)university,USTB has developed into a multidisciplinary research-orientated university with distinctive characteristics.

摘要： Ultra-thick steep coal seam mining will inevitably lead to the increase of greater and violent ground subsidence and deformation.A subsidence control method by inversely-inclined slicing and upward mining is proposed in this paper.By this method,the sequence of collapse of overlying strata and the direction of propagation of strata movement are changed,the extent of roof-side deformation thereby is lessened,and boundary angle of roof-side subsidence is reduced by 5°-10°.The mechanism of this mining method for control of strata movement has been evidenced by numerical simulation and experiments with similarity materials.A subsidence prediction model based on the variation of mining influence propagation angle can be used to evaluate the surface movement and deformation of the mining method.The application of the method in No.3 Mine in Yaojie mining area has yielded the expected result.

摘要： Zambia’s economy is fueled by copper production, which is one of the country’s most important industries. In terms of copper output, Zambia has around five large open-pit mines and eight significant underground mines. Zambia’s Government owns a stake in some of these businesses. This article examines the economic, social, technological, and environmental ramifications of copper mining in the Copperbelt area of Zambia.

摘要： Advances in numerical simulation techniques play an important role in helpingmining engineers understand those parts of the rock mass that cannot be readily observed.The Material Point Method(MPM)is an example of such a tool that is gaining popularity for studying geotechnical problems.In recent years,the original formulation of MPM has been extended to not only account for simulating the mechanical behaviour of rock under different loading conditions,but also to describe the coupled interaction of pore water and solid phases in materials.These methods assume that the permeability of mediums is homogeneous,and we show that these MPM techniques fail to accurately capture the correct behaviour of the fluid phase if the permeability of the material is heterogeneous.In this work,we propose a novel implementation of the coupled MPM to address this problem.We employ an approach commonly used in coupled Finite Volume Methods,known as the Two Point Flux Approximation(TPFA).Our new method is benchmarked against two well-known analytical expressions(a one-dimensional geostatic consolidation and the so-called Mandel-Cryer effect).Its performance is compared to existing coupled MPM approaches for homogeneous materials.In order to gauge the possible effectiveness of our technique in the field,we apply ourmethod to a case study relating to a mine known to experience severe problems with pore water.

摘要： Dear Editor,This letter develops two new self-training strategies for domain adaptive semantic segmentation,which formulate self-training into the processes of mining more training samples and reducing influence of the false pseudo-labels.Particularly,a self-training strategy based on entropy-ranking is proposed to mine intra-domain information.

摘要： The association of radiation with matter,being it from external means(i.e.external sources)or from internal pollution of the body by toxic substances,can pose biological hazard which may show the clinical symptoms later.The nature and extent of these symptoms and the time they take to appear are a function of the amount of radiation absorbed and the rate at which it is received.This study aimed at assessing the health effects of radiation exposure to human sensitive organs across some selected mining sites of Plateau State Nigeria.Finding of this study have revealed that the mean Dorgan values for the lungs,ovaries,bone marrow,testes,kidney,liver and whole body for different mining points of Plateau State are 0.29 mSv/y,0.26 mSv/y,0.31 mSv/y,0.36 mSv/y,0.28 mSv/y,0.21 mSv/y and 0.30 mSv/y respectively.From the findings presented,it can be concluded that the background radiation in Plateau State is not an issue of health concern in regards to sensitive organs and may not course immediate health effect except when accumulated over long period of time which may cause cancer to the indoor members on approximately seventy years of exposure.

摘要： There’s a lot of value in data.The collection,fusion and mining of multi-source data will release the potential of data and bring into play the value of data.At the same time,due to their respective interests and risks of privacy exposure,there are obstacles in the development of mul­ti-data fusion,and the phenomenon of“isolated data is­land”is common,which hinders the development of data fusion.

摘要： An adverse effect resulting from explosive mine blasts is the production of toxic nitrogen oxides(NO and NO_(2))and carbon monoxide(CO).The empirical measurements of the concentration of toxic gases showed that it depends not only on the composition of an explosive and properties of its ingredients but also on several other parameters,such as volume of blasting chamber,explosive charge mass and design,confinement characteristics,surrounding atmosphere,etc.That explains why measured concentrations of toxic gases reported in literature significantly differ.In this paper,we discuss the possibility of theoretical prediction of the concentration of toxic gases by thermochemical equilibrium calculation applying two models:ideal detonation model and deflagration model.It can be demonstrated that thermochemical calculations can provide a good estimation of the measured concentrations and reproduce experimentally obtained effects of additives on the production of toxic gases.It was also found that the ideal detonation model applies to heavily confined explosive charges,while the deflagration model is more suitable for low detonation velocity explosives with light confinement.

摘要： 纽约证券交易所上市的加里东矿业公司(Caledonia Mining Corporation)宣布,其控股的毛毯矿(Blanket Mine)2020年的黄金产量达到创纪录水平,全年总产量达到近5.8万盎司。2019年公司黄金产量是55,182盎司。