scholarly journals Development of explosive breaking principles for the ores prone to overgrinding

2020 ◽  
Vol 192 ◽  
pp. 01016
Author(s):  
Artem Rozhkov ◽  
Igor Sokolov ◽  
Yuri Antipin ◽  
Kirill Baranovsky

In underground mining of valuable non-metallic raw materials, non-ferrous and precious metal ores, the problem of overgrinding of raw materials as a result of blasting operations is quite acute. For ores of nonferrous and precious metals, represented by strong rocks, the effect of increased concentration of ore minerals in small classes of ore is characteristic. Due to the process of segregation of the mass in ore drawing, small fractions accumulate in significant quantities on the lying side of the mine goaf and on the roughness of its surface. Such ore is often simply lost. It is rational to create conditions for reducing the yield of small fractions already at the stage of separating the ore from the array. Therefore, the development of technological methods for managing the quality of mining enterprise products and methods for improving the completeness of extracting mineral reserves is an urgent scientific and technical task. To solve this problem, a number of model and full-scale experiments were conducted to identify the dependence of the nature of destruction on the method and parameters of blasting, followed by statistical evaluation of the results. The principles of determining the parameters of the technology for breaking valuable ores that are prone to overgrinding are established.

Author(s):  
A. A. Smirnov ◽  
K. V. Baranovskiy ◽  
A. A. Rozhkov

During underground mining of deposits of valuable non-metallic raw materials, nonferrous and precious metal ores, the problem of their overgrinding as a result of blasting is quite acute. Overgrinding of valuable non-metallic raw materials leads to an actual decrease in the yield of concentrates or final products, due to the rather stringent requirements of the enrichment technology for the conditional size of the piece and the structural safety of the useful component. Non-ferrous and precious metal ores represented by strong rocks are characterized by the effect of increased concentration of ore minerals in small classes of ore. Due to the process of segregation on ore drawing, small fractions in significant quantities accumulate on the lying side of the goaf and its unevenness. Such ore with a high content of useful component requires additional technological measures for its extraction or is simply lost. Consequently, the development of technological methods for managing the quality of products of a mining enterprise and methods for increasing the completeness of extracting mineral resources are an urgent scientific and technical task. To solve it, an analysis of theory and practice in the study area was carried out, which showed that the existing methods for additional extraction of fine ore fractions in mining systems with an open goaf are laborintensive and resource-intensive, not universal, ineffective and often not safe. It is rational to create conditions for reducing the yield of fine fractions already at the stage of ore blasting As a result, determining parameters principles for breaking technology of strong fractured ores are proposed. Developed guidelines and recommendations for blasthole ring charges. Dependences the technical and economic indicators of ore explosive blasting from its structural and technological parameters are obtained.


2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Abdul-Majeed Azad ◽  
Desikan Sundararajan

Fuel processors are required to convert sulfur-laden logistic fuels (jet fuels, diesel, and coal) into fuel cell quality hydrogen-rich reformate with little or no sulfur for extended periods. Sulfur poisons and deactivates the reforming catalyst, therefore, sulfur-tolerant catalysts ought to be developed. In this paper, the development, characterization, and evaluation of a series of nanoscale ceria-supported reforming catalysts containing three noble metals in low concentration (1 wt% ≤ total metal loading ≤ 1.33 wt%) for the steam-reforming of kerosene (a JP-8 surrogate) are reported. Their performance is quantified in terms of H2yield, tolerance towards sulfur in the fuel, and the on-stream stability and compared with that of monometal and bimetal analogs under identical conditions. Due to the inherent cooperative synergy, a trimetal catalyst was found far superior to its mono- and bimetallic analog containing same amount of the precious metal loading in terms of quality of the reformate (measured by H2level in steady-state) as well as the catalyst longevity on-stream prior to deactivation. At the same time a mechanistic correlation between the distinct role of a given precious metal and the extent of its loading in each of the formulations and quality of the corresponding desulfurized H2-rich reformate was discovered.


Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 331 ◽  
Author(s):  
Tadsuda Taksavasu ◽  
Thomas Monecke ◽  
T. Reynolds

Silica sinters forming at the Wairakei geothermal power plant in New Zealand are composed of noncrystalline opal-A that deposited rapidly from cooling geothermal liquids flashed to atmosphere. The sinter is laminated with alternating layers of variably compacted silicified filamentous microbes encased by chains of fused silica microspheres. Microscopic inspection of bonanza quartz vein samples from the Buckskin National low-sulfidation epithermal precious metal deposit in Nevada showed that colloform bands in these veins exhibit relic microsphere textures similar to those observed in the silica sinters from the Wairakei power plant. The textural similarity suggests that the colloform bands were originally composed of noncrystalline opal-A that subsequently recrystallized to quartz. The colloform bands contain dendrites of electrum and naumannite that must have grown in a yielding matrix of silica microspheres deposited at the same time as the ore minerals, implying that the noncrystalline silica exhibited a gel-like behavior. Quartz bands having other textural characteristics in the crustiform veins lack ore minerals. This suggests that ore deposition and the formation of the colloform bands originally composed of compacted microspheres of noncrystalline silica are genetically linked and that ore deposition within the bonanza veins was only episodic. Supersaturation of silica and precious metals leading to the formation of the colloform bands may have occurred in response to transient flashing of the hydrothermal liquids. Flashing of geothermal liquids may thus represent a key mechanism in the formation of bonanza precious metal grades in low-sulfidation epithermal deposits.


Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5217
Author(s):  
Sean McCarthy ◽  
Alvin Lee Wei Jie ◽  
D. Christopher Braddock ◽  
Angela Serpe ◽  
James D. E. T. Wilton-Ely

The direct use in catalysis of precious metal recovery products from industrial and consumer waste is a very promising recent area of investigation. It represents a more sustainable, environmentally benign, and profitable way of managing the low abundance of precious metals, as well as encouraging new ways of exploiting their catalytic properties. This review demonstrates the feasibility and sustainability of this innovative approach, inspired by circular economy models, and aims to stimulate further research and industrial processes based on the valorisation of secondary resources of these raw materials. The overview of the use of recovered gold and palladium in catalytic processes will be complemented by critical appraisal of the recovery and reuse approaches that have been proposed.


Author(s):  
A.V. Zatonskiy ◽  
◽  
P.A. Yazev ◽  

In this article, we show the importance of potash fertilizers produced by PJSC Uralkali, Berezniki, Perm Territory for agriculture and the economy in general. А process of potas¬sium ore underground mining is described from breaking up moment till transportation to the surface. An importance of production planning for the mining enterprise functioning is substantiated. Various levels of plan-ning, from a general production plan to a weekly and daily plans are described. The problem of such planning at PJSC Uralkali is in using only integral performance indicators, it leads to significant errors. It is proposed to use simulation modeling as a possible solution to the problem. Purpose of work. The purpose of this work is to develop a simulation model of mining operations, from the process of breaking and transporting ore to a conveyor-transport system, and to test model’s applicability for ore mining planning. Since the existing software has a number of limitations in applies to potash mines, a specialized object-oriented library allows modeling queuing systems, multi-agent and active systems is used as a basis for modeling. The limitations and as-sumptions of the model are described. Materials and methods. The model is igned as a determinis-tic automaton. The end point for ore mining process modeling is the transfer of ore to the unloading point, because further transportation of ore is not a limiting factor for mining. Conclusion. The spe-cial states of all objects of the system including mining combine – self-propelled car – unloading point and all possible transitions between them are described. A data from open sources is taken to check the adequacy of the model. Changes in the simulation results are investigated for various in-put parameters in the developed software. The simulation results are of a pulsating character due to the periodic execution of the harvester drive away. A productivity of the combine decreases with an increase in the distance traveled by a self-propelled car. The possibility of transition to a stochas-tic model is investigated. An expected decrease due to an increase in the downtime of the combine is shown. A conclusion about the applicability of the model to improve the quality of planning for un-derground potassium ore mining is made based on obtained data.


2016 ◽  
Vol 858 ◽  
pp. 366-370
Author(s):  
Adilkhan Baibatsha ◽  
Kulyash Dyussembayeva ◽  
Alma Bekbotayeva

Total reserves in tails in enrichment factories account for about 1.0 billion tons, and they contain copper, lead, zinc and precious metals. Therefore such tailings can be considered a major technological company and a reliable source of raw materials to build of processing company. We have studied the conditions of distribution and storage of tailings from enrichment plants. Microscopic description of the tailings material gave the following data. Chalcopyrite prevalent among the copper minerals covellite is most common in the second place, rare chalcocite, bornite, sphalerite, pyrite, arsenopyrite. The grain size of the sulfides is generally 0.01-0.03 mm. The sulfides are mainly quartz or fused to it. Rarely observed aggregates are covellite-bornite, chalcopyrite-covellite and chalcopyrite-bornite. However, not all sulphides ore sufficiently disclosed, most of them are located within grains the surrounding rocks. If disclosed ore minerals associated with grains of rocks less than 100 microns, they can be readily available for leaching. To increase the fullness of extraction of metals from sulfide located inside rock grains larger than 150-200 microns, additional measures for their opening.


2020 ◽  
Author(s):  
Lauren R. Zeeck ◽  
Thomas Monecke ◽  
T. James Reynolds ◽  
Erik R. Tharalson ◽  
Katharina Pfaff ◽  
...  

Abstract The Miocene low-sulfidation epithermal deposits of the Omu camp in northeastern Hokkaido, Japan, are small past-producers of precious metals and represent significant exploration targets for high-grade Au and Ag ores. The quartz textures of ore samples and the distribution of ore minerals within quartz veins were studied to identify the processes that resulted in the bonanza-grade precious metal enrichment in these deposits. In the high-grade vein samples, which are crustiform or brecciated in hand specimen, ore minerals exclusively occur within colloform quartz bands. High-magnification microscopy reveals that ore-bearing colloform bands consist of fine-grained quartz exhibiting relic microsphere textures and quartz having a mosaic texture that formed through recrystallization of the microspheres. The presence of relic microspheres is evidence that the microcrystalline quartz hosting the ore minerals formed through recrystallization of a noncrystalline silica precursor phase. The ore-hosting colloform bands composed of agglomerated microspheres alternate with barren colloform quartz bands that are composed of fibrous chalcedonic quartz and mosaic quartz formed through recrystallization of the chalcedony. The findings of this study are consistent with previous models linking bonanza-grade precious metal enrichment and the formation of bands of noncrystalline silica in low-sulfidation epithermal veins to episodic vigorous boiling or flashing of the hydrothermal system in the near-surface environment.


2020 ◽  
Vol 839 ◽  
pp. 86-92
Author(s):  
Irina G. Endzhievskaya ◽  
Nina G. Vasilovskaya ◽  
Oksana V. Gofman ◽  
Nadezhda Y. Klindukh ◽  
Vladislav A. Kulik

This article presents the results of experimental studies aimed at improving the physicomechanical properties of effective hollow ceramic stones using various technological methods that will disperse, homogenize and structure the ceramic mixture by introducing industrial waste with high alumina content, dispersed reinforcement, and also mechanical activation of the molding material, accompanied by the fragmentation of clay particles to a colloidal degree of dispersion, allows eliminating the aging process. The main molding characteristics of the investigated mixtures were determined, X-ray phase analysis of ceramic masses and a shard of the control composition was performed and after dispersion, activation modes were worked out, strength characteristics of ceramic samples made of dispersed clay raw materials were determined.


Author(s):  
Н.А. ШМАЛЬКО

Применение рациональных технологий пшеничных хлебобулочных изделий с использованием нетрадиционного сырья – амарантовой муки, полученной из зерна амаранта, является технологическим приемом повышения эффективности хлебопекарного производства. Рассматриваемые в статье технологии с использованием амарантовой муки основаны на выборе режимов и способов тестоприготовления: опарного (на обычной густой опаре, на густой опаре с пофазным внесением соли), на жидкой опаре (с сокращением периода брожения), безопарного (с сокращением периода брожения, с применением активированных дрожжей). Внесение в состав питательной среды бродильных полуфабрикатов амарантовой муки позволяет интенсифицировать процесс тестоприготовления, улучшить степень разрыхления мучного полуфабриката и повысить вкусовые свойства готового изделия, что определяется достижением объективизации критериев адаптированности и выброженности мучной среды. Добавление амарантовой муки рекомендуется производить в случае переработки традиционной пшеничной муки с пониженными хлебопекарными свойствами, требующей применения технологических приемов и способов тестоприготовления, характерных для комплексных технологий хлебобулочных изделий. Разработанные способы производства хлеба из пшеничной муки прошли апробацию в промышленных условиях, что показало целесообразность их внедрения для повышения технологических свойств полуфабрикатов, улучшения вкусовых и иных качеств выпекаемой продукции. Стабилизация и улучшение качества хлебобулочных изделий, выработанных с использованием амарантовой муки, для каждого конкретного примера поточно-механизированной линии достигается путем подбора комплексной технологии при переработке пшеничной муки с пониженными хлебопекарными свойствами для определения соответствия выпеченной продукции нормам качества, отраженным в стандартной и технической документации. The use of rational technologies of wheat bakery products using non-traditional raw materials - amaranth flour obtained from amaranth grain, is a technological method in order to increase the efficiency of bakery production. The technologies considered in the article using amaranth flour are based on the choice of modes and methods of dough preparation: sponge (on ordinary thick dough, on thick dough with phase-by-phase salt addition), on liquid dough (with a reduction in the fermentation period), non-steam (with a reduction in the fermentation period, with using activated yeast). The addition of amaranth flour to the nutrient medium of fermenting semi-finished products allows intensifying the dough preparation process, improving the degree of loosening of the flour semi-finished product and increasing the taste properties of the finished product, which is determined by the achievement of objectification of the criteria for adaptability and fermentation of the flour medium. The addition of amaranth flour is recommended in the case of processing traditional wheat flour with reduced baking properties, requiring the use of technological methods and methods of dough preparation typical for complex technologies of bakery products. The developed methods for the production of bread from wheat flour were tested in industrial conditions, which showed the feasibility of their implementation to improve the technological properties of semi-finished products, improve the taste and other qualities of baked products.Stabilization and improvement of the quality of bakery products made using amaranth flour for each specific example of a flow-mechanized line is achieved by selecting a comprehensive technology for processing wheat flour with reduced baking properties to determine the compliance of baked products with the quality standards reflected in the standard and technical documentation.


Author(s):  
K. G. Starkova ◽  
O. V. Dolgikh ◽  
A. V. Krivtsov ◽  
O. A. Kazakova ◽  
A. A. Mazunina

Introduction. Identification of markers of genetic variability that determine the formation of professionally caused diseases of the cardiovascular system will allow to identify potential risk groups among workers and optimize the program of preventive and diagnostic measures.The aim of the study was to analyze the features of polymorphism of eNOS and HTR2A genes and regulatory indicators in workers at the mine mining enterprise with diseases of the cardiovascular system.Materials and methods. The men working at the enterprise on mine extraction of ore minerals, with pathology of cardiovascular system are examined. Real-time polymerase chain reaction and allelic discrimination were used to identify genotypes. Regulatory markers nitric oxide and serotonin were determined by enzyme immunoassay.Results. In the observation group, an increase in the frequency of polymorphic variants of eNOS G894T genotype GG 1.4 times and allele G 1.2 times, significantly associated with the development of cardiovascular disease (OR=3.16; Cl 95%=1.14– 8.76), as well as the presence of excessive frequency of minor allele G gene HTR2A (rs7997012) relative to the comparison group (1.8 times) due to mutant homozygous genotype GG (2.7 times) (OR=2.45; CL 95%=1.03–5.87), acting as risk FACTORS for cardiovascular disorders in the group of miners. At the same time, polymorphism of eNOS and HTR2A gene variants was combined with an imbalance in the level of CCC regulatory markers — nitric oxide and serotonin.Conclusions. Genetic variations of the eNOS g894t and HTR2A (rs7997012) genes can be recommended as sensitivity markers in monitoring and identification of risk groups among workers in underground mining.


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