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ISSN 0536-1028 (Print) ISSN 2686-9853 (Online) |
УДК 338.23:330.52(98) | DOI: 10.21440/0536-1028-2019-8-97-107 | Download | ![]() |
Abstract Introduction. A promising area of replenishing the resource base for placer gold mining could be the involvement of high clay content deposits. Important scientifi c and practical problem with this solution is improving the quality of sand preparation for enrichment due to high-quality disintegration. Solving the problem requires not only creating more effi cient clay sands disintegrators, but also study of sand granulometry, evaluation of their physical and mechanical properties, the material composition of the mineral rock mass. The composition of the hard-to-wash sands of the Far East shows that the clay content in them varies widely and can reach 60% or more. Analysis of the existing methods of sands deposits disintegration shows that the use of traditional methods of rock preparation for enrichment will not allow to fully solving the problem of processing high-clay alluvial deposits.
Research aim is the development of a scheme for processing high-clay sands using a high-pressure hydrodynamic disintegrator based on the principle of the effect of hydrodynamic cavitation.
Research methodology. The experiments have been carried out on high-clay sand processing with a laboratory disintegration facility with various cavity activators.
Results. In the course of the study, the design of the device for the disintegration of high-clay sands was developed and proposed for practical implementation, allowing to reduce the loss of gold in the enrichment of high-clay sands on sluice washers, as well as to engage in mining alluvial deposits with high clay content, mining of which was previously considered unprofitable. The use of this technological scheme will make it possible to switch from a two-stage technology for the processing of placers to a one-stage, incorporating the processing of sands and effel into a single technological process, eliminating the costs of processing man-made alluvial sands of gold deposits.
Key words: placer gold deposit; high clay content sands; disintegration; cavitation; hydrodynamic disintegrator.
REFERENCES
Received 7 May 2019
УДК 622.342.1 | DOI: 10.21440/0536-1028-2019-8-88-96 | Download | ![]() |
АННОТАЦИЯ
Введение. Перспективным направлением пополнения сырьевой базы россыпной золотодобычи может стать вовлечение в эксплуатацию месторождений с высоким содержанием глины. Важной научно-практической задачей при этом является решение проблемы повышения качества подготовки песков к обогащению за счет качественной дезинтеграции. Решение проблемы требует не только создания более эффективных аппаратов для дезинтеграции глинистых песков, но и изучения гранулометрии песков, оценки их физико-механических свойств, вещественного состава минеральной горной массы. Состав труднопромывистых песков Дальнего Востока показывает, что содержание глины в них изменяется в широких пределах и может достигать 60 % и более. Анализ существующих способов дезинтеграции песков месторождений показывает, что использование традиционных способов подготовки породы к обогащению не позволит в полном объеме решить проблему переработки высокоглинистых россыпей.
Цель работы. Разработка схемы переработки высокоглинистых песков с применением высоконапорного гидродинамического дезинтегратора, в работе которого использован эффект гидродинамической кавитации.
Методика исследований. Выполнены эксперименты по переработке высокоглинистых песков на лабораторной дезинтегрирующей установке с различными активаторами кавитации.
Результаты. В ходе проведения исследования разработана и предложена к практической реализации конструкция установки для дезинтеграции высокоглинистых песков, позволяющая сократить потери золота при обогащении высокоглинистых песков на шлюзовых промывочных приборах, а также вовлекать в отработку россыпные месторождения с высоким содержанием глины, отработка которых ранее считалась нерентабельной. Использование данной технологической схемы позволит перейти от двухстадийной технологии переработки россыпей к одностадийной, включив в единый технологический процесс переработку песков и эфелей, исключив затраты на переработку техногенных песков россыпных месторождений золота.
Ключевые слова: россыпное месторождение золота; высокоглинистые пески; дезинтеграция; кавитация; гидродинамический дезинтегратор.
БИБЛИОГРАФИЧЕСКИЙ СПИСОК
Поступила в редакцию 7 мая 2019 года
Podkorytov V. N., Mochalova L. A. Analysis of commodity prices impact on the manageability of market capitalization of an oil and gas company. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal = News of the Higher Institutions. Mining Journal. 2019; 7: 122–131 (In Russ.). DOI: 10.21440/0536-1028-2019-7-122-131
Research aim. The research is focused on the analysis of commodity prices impact on the manageability of company’s market capitalization by the example of the largest public joint stock companies of oil and gas producing industry abundant at the national stock market. Research object is prices for commodity (oil and natural gas) and stock prices of PJSC Gazprom, PAO Novatek, PJSC Rosneft, PJSC LUKOIL, PJSC Tatneft, PJSC Surgutneftegas. Research methodology and tools. Within the framework of the regression analysis carried out by the authors, the price of 1 barrel of oil and 1 Mmbtu of natural gas were accepted as a factor indicator (closing monthly futures) expressed in US dollars. The price of 1 stock item of an oil and gas company (monthly closing prices) expressed in US dollars.
Results. The regression analysis has shown the following. Firstly, there is some dependence between oil and gas companies stock prices and oil prices, with other external and internal cost factors the given connection is rather strong for several enterprises. Secondly, dependence between stock prices of gas producing companies and prices for natural gas is unobvious which is probably connected with speculative short term spikes in the stock market and results in the need to use monthly median prices. Thirdly, PJSC Surgutneftegas stock prices independence from commodity prices may indicate that attracting investment by means of securities realization in the stock market is not a priority task. Scope of research. Research results may be used by the investors willing to invest in shares of oil and gas companies and by these companies’ managers when controlling their cost.
Summary. The outcome of the research is the following. Firstly, oil and gas companies differ and require not general, but individual approach to cost factor models development. Secondly, when calculating, the use of only one cost factor is not very reasonable, therefore multifactor regression model development is required when managing the cost of a company.
Key words: oil and gas company; company’s market capitalization; price for oil; price for natural gas; price for a stock item; cost factors; company’s cost management.
REFERENCES
Received 18 July 2019
УДК 622.7.09 | DOI: 10.21440/0536-1028-2019-8-81-87 | Download | ![]() |
АННОТАЦИЯ
Introduction. Well-known formulae make it possible to analytically calculate the random error of mass-reduction at samples preparation and their preparation for analysis, which is also true for weighted samples collection for analysis; it helps to calculate, analyze and optimize the circuits of samples preparation, including reference standards preparation. All these values can be determined by means of direct measuring, but the performer’s qualifcation cannot be taken into account.
Research aim is to determine and test the sample reduction error formula coefcient which takes into account the quality of performers work at sampling.
Research methodology. For experimental evaluation of performance quality, gold and silver side-by-side assays of gold concentrate in two independent laboratories were carried out, which allow determining the repeatability error by duplicate analysis. The comparison was carried out of the two laboratories’ work on random repeatability errors determination.
Results. It has been proposed to use the coefcient of the performer’s work quality when calculating random errors of samples preparation for analysis. Coefcient’s application is shown by the example of gold-bearing product preparation circuit design.
Conclusions. The formula which calculates the error of mass-reduction caused by the reduction of sample mass describes the procedure of ideal reduction until the quality of the performer’s work is taken into consideration. When calculating and analyzing sample preparation circuits (including weighted samples collection for analysis), the error should be taken into account, which is introduced due to the imperfect process by the performer. The ratio of reproducibility error to repeatability error in analysis procedures produces the coefcient of imperfection of performing the operation of weighted samples collection for analysis from the package, which is 1.1–1.6 for noble metal ore, and 1.2–1.4 for nonferrous metal ore. Experimental determination of sample preparation errors and their comparison with expected values make it possible to estimate the quality of laboratories’ work and take measures to improve their work.
Key words: reproducibility; repeatability; random error; samples preparation for analysis; coefcient of performance.
REFERENCES
Received 4 September 2019
Aleshin D. S., Khalezov B. D., Krasheninin A. G. Molybdenum mineral base. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal = News of the Higher Institutions. Mining Journal. 2019; 7: 113–121 (In Russ.). DOI: 10.21440/0536-1028-2019-7-113-121
Introduction. Molybdenum production is important for Russia’s economic development. About 80% of the produced metal is used in special steel manufacture.
Research aim. Based on the data about reserves, extraction and production of molybdenum, the researches aim is to identify world leaders in the market, show and describe basic molybdenum deposits at the territory and the Russian Federation, analyse production dynamics of molybdenum concentrates and ferromolybdenum within recent years, specifying main manufacturing enterprises in Russia.
Methodology basically included theoretical research methods, particularly review and analysis of various sources of information.
Results. The present article displays brief analytical review of molybdenum world market and indicates main manufacturers of consumers of the concentrate. World leaders in molybdenum reserves are determined. The dynamics of molybdenum concentrates global production is presented for the period from 2012 to 2018. Mineral raw material base is described and main deposits of molybdenum at the territory of Russia are shown. The dynamics of molybdenum concentrate production in 2012–2017 is reflected with the list of manufacturing enterprises. Ferromolybdenum production dynamics is given. Change in molybdenum concentrates and ferromolybdenum import-export is shown.
Key words: molybdenum; molybdenum ores; production; export-import.
REFERENCES
Received 6 June 2019
This work is licensed under a Creative Commons Attribution 4.0 International License.