Improving rock classification in terms of explosivity

Purpose. To improve rock classification in terms of explosivity relying upon the detailed analysis of characteristics of rating classifications available in the Russian Federation and in the world. Methods. Complex approach has been applied involving comparison of sizes of particle-size fractions determined in terms of both national and the world standards; information gathering and processing as for the available classifications intended to identify difficulties of rock explosivity; compilation of comparative systematic of classifications or methods being considered. Findings. Both national and the world rock classifications in terms of explosivity have been considered. While comparing national classifications as for the difficulties of rock mass failure (i.e. explosivity), a comparative table has been compiled where the most popular rock classifications are compared. Analysis of the world practices, concerning compilation of rock classifications in terms of explosivity, has shown that their approaches differ from Russian ones slightly. In the first instance, they are empiric dependences being calculated for each rock mass type separately in any single case. It has been determined that geomechanical classification of D. Lobshir (MRMR) is the most popular and rating world system to evaluate rock explosivity. It has been demonstrated that while compiling such classifications, foreign scientific writers put an emphasis on physical and mechanical indices of rocks (i.e. density, fissility, compression strength, tensile strength etc.) as well as on mine engineering ones (i.e. line of the least resistance, well diameter and depth, stope height etc.) which determines essential reliability of calculation of drilling-and-blasting parameters. Originality. The research is the first stage of the development of the unified transition classification from Russian explosivity scales to the comparable world methodic practices as for rock mass explosivity. Practical implications. To perform rapid transition from one explosivity classification to the other. The findings are recommended to be used while projecting drilling and blasting operations in the context of any types of minerals and in the context of academic activity.Мета. Вдосконалення класифікації гірських порід за вибуховістю на основі детального аналізу особливостей існуючих російських і закордонних рейтингових класифікацій. Методика. Застосовано комплексний методичний підхід, що включає зіставлення розмірів гранулометричних фракцій, які визначали згідно вітчизняним і закордонним стандартам; збір та обробка інформації щодо існуючих класифікацій визначення труднощів вибуховості гірських порід; складання зіставної класифікації розглянутих класифікацій або методик. Результати. Розглянуто вітчизняні та закордонні класифікації гірських порід за вибуховістю. При порівнянні вітчизняних класифікацій в частині труднощів руйнування гірського масиву (вибуховості) була побудована порівняльна таблиця, в якій між собою зіставляються найбільш популярні класифікації гірських порід. При аналізі закордонного досвіду складання класифікацій гірських порід за вибуховістю було виявлено, що їх мето- ди дещо відрізняються від російських, і являють собою емпіричні залежності, та розраховуються для кожного типу масиву в кожному окремому випадку індивідуально. Встановлено, що найбільш популярною і рейтинговою системою для оцінки вибуховості гірських порід за кордоном є геомеханічна класифікація Д.Х. Лабшіра (MRMR). Показано, що закордонні автори, при складанні класифікацій, роблять акцент не лише на фізико- механічних показниках гірських порід (щільності, тріщинуватості, межі міцності на стиск і розтяг і т.д.), але й на гірничотехнічних (лінія найменшого опору, діаметр та глибина свердловини, висота забою і т.д.), що визначає суттєву достовірність розрахунку параметрів буропідривних робіт. Наукова новизна. Представлена робота є першим кроком до розробки єдиної перехідної класифікації від російських шкал за вибуховістю до аналогічних закордонних методичним практикам в частині вибуховості гірського масиву. Практична значимість полягає в можливості швидкого переведення однієї класифікації за вибуховістю в іншу. Результати роботи рекомендується використовувати при проектуванні буропідривних робіт на всіх типах родовищ корисних копалин, а також у навчальному процесі.Цель. Совершенствование классификации горных пород по взрываемости на основе детального анализа особенностей существующих российских и зарубежных рейтинговых классификаций. Методика. Применен комплексный методический подход, включающий сопоставление размеров гранулометрических фракций, определяемых по отечественным и зарубежным стандартам; сбор и обработка информации о существующих классификациях определения трудности взрываемости горных пород; составление сопоставительной классификации рассматриваемых классификаций или методик. Результаты. Рассмотрены отечественные и зарубежные классификации горных пород по взрываемости. При сравнении отечественных классификаций в части трудности разрушения горного массива (взрываемости) была построена сопоставительная таблица, в которой между собой сопоставляются наиболее популярные классификации горных пород. При анализе зарубежного опыта составления классификаций горных пород по взрываемости было выявлено, что их методы несколько отличаются от российских, и представляют собой эмпирические зависимости, и рассчитываются для каждого типа массива в каждом отдельном случае индивидуально. Установлено, что наиболее популярной и рейтинговой системой для оценки взрываемости горных пород за рубежом является геомеханическая классификация Д.Х. Лабшира (MRMR). Показано, что зарубежные авторы, при составлении классификаций, делают акцент не только на физико-механические показатели горных пород (плотность, трещиноватость, пределы прочности на сжатие и растяжение и т.д.), но и на горнотехнические (линия наименьшего сопротивления, диаметр и глубина скважины, высота забоя и т.д.), что определяет существенную достоверность расчёта параметров буровзрывных работ. Научная новизна. Представленная работа является первым шагом к разработке единой переходной классификации от российских шкал по взрываемости к аналогичным зарубежным методическим практикам в части взрываемости горного массива. Практическая значимость. Заключается в возможности быстрого перевода одной классификации по взрываемости в другую. Результаты работы рекомендуется использовать при проектировании буровзрывных работ на всех типах месторождений полезных ископаемых, а также в учебном процессе.The research is carried out by a team of authors of Mine and Underground Construction Department at Siberian Federal University as part of a grant of the Russian Federation President for governmental support of young Russian scientists-Candidates of Sciences (МК-1178.2018.8)

A Brief History of the Development of Blasting and the Modern Theory of Rock Breaking

The article is devoted to the task today to improve the effectiveness of blasting during construction of horizontal and inclined mine excavations. Construction of new and reconstruction of existing mines requires large volume of excavation works, which length can reach tens of kilometers for only one project. Drilling and blasting workings allow not only to break out rocks from a frontal part of an excavation, but also cause an internal effect, which can lead to undesired damage that, in turn, often lead to increased expenses for excavation operations and safety problems for personnel. Calculation methods for blasting and explosion operations is a topical issue in mining industry as they allow to improve characteristics of excavation works and safety of explosion operations. Dozens of scientists offer their design, which reflects the vision of the problem and its solution. There are many methods for calculating the parameters of drilling and blasting, but so far not developed a uniform methodology of calculation, which would encompass all the factors and explained the mechanism of formation of cracks around the explosive charge and the process of breaking rock. The paper presents a novel methodology for calculations for blasting and explosion operations. That methodology comprises various specifics of rock geology and mining engineering during works in horizontal and vertical excavations. In this paper given an algorithm for calculation two main areas of destruction: crushed zone and fracturing zone. In addition, article outlines main aspects of Mining Engineering Development from Antiquity until present days and presents the dynamic of mineral resources

New technical solutions for ventilation in deep quarries

The paper discusses the issues of ventilating in deep quarries caused by the intensification of blasting operations at great depths, the increased distance of ore truck transportation to the daylight area, constant change in the geometrical parameters of the quarry, its microrelief and direction of mining, and increased isolation of the mined space from the environment. We provide a brief analysis of the current tools for forced airflow in deep quarries, which showed that the use of forced ventilation is often challenging since it leads to high energy consumption, high level of noise exceeding the permissible parameters, and high speeds of forced air flows may blow the dust off the quarry surfaces. The article presents methods and tools developed at the Siberian Federal University for intensifying the natural airflow in deep quarries by changing the air density at the entrance and exit points of the pit, as well as heating the shady areas using mirrors and solar energy, which do not interfere with mining and blasting operations

Strongly Enhanced Photovoltaic Performance and Defect Physics of Air-Stable Bismuth Oxyiodide (BiOI)

Bismuth-based compounds have recently gained increasing attention as potentially nontoxic and defect-tolerant solar absorbers. However, many of the new materials recently investigated show limited photovoltaic performance. Herein, one such compound is explored in detail through theory and experiment: bismuth oxyiodide (BiOI). BiOI thin films are grown by chemical vapor transport and found to maintain the same tetragonal phase in ambient air for at least 197 d. The computations suggest BiOI to be tolerant to antisite and vacancy defects. All-inorganic solar cells (ITO|NiO$_x$|BiOI|ZnO|Al) with negligible hysteresis and up to 80% external quantum efficiency under select monochromatic excitation are demonstrated. The short-circuit current densities and power conversion efficiencies under AM 1.5G illumination are nearly double those of previously reported BiOI solar cells, as well as other bismuth halide and chalcohalide photovoltaics recently explored by many groups. Through a detailed loss analysis using optical characterization, photoemission spectroscopy, and device modeling, direction for future improvements in efficiency is provided. This work demonstrates that BiOI, previously considered to be a poor photocatalyst, is promising for photovoltaics.R.L.Z.H. thanks Magdalene College, Cambridge. L.C.L. and J.L.M.-D. thank the EPRSC Centre for Doctoral Training: New and Sustainable Photovoltaics, and the Cambridge Winton Programme for the Physics of Sustainability for funding. T.N.H. thanks the Cambridge Graphene Centre, funded by the EPSRC. K.H.L.Z. was supported by the Herschel Smith fellowship. The U.S.-based theory and synthesis portions of this work were supported primarily as part of the Center for Next Generation Materials by Design (CNGMD), an Energy Frontier Research Center funded by the DOE Office of Science, Basic Energy Sciences under Contract No. DE-AC36-08GO28308. The MIT-based characterization portion of this work was supported primarily through a TOTAL SA research grant funded through MITei, as well as a SusChem grant funded by the National Science Foundation (No. CBET-1605495). The TCSPC work was supported as part of the Center for Excitonics, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0001088 (MIT). The computations were performed using resources sponsored by the Department of Energy’s Office of Energy Efficiency and Renewable Energy and located at the NREL. The authors also acknowledge the MRSEC Shared Experimental Facilities at MIT, supported by the National Science Foundation (No. DMF-08019762)

Perovskite-Inspired Photovoltaic Materials: Toward Best Practices in Materials Characterization and Calculations

Recently, there has been an explosive growth in research based on hybrid lead–halide perovskites for photovoltaics owing to rapid improvements in efficiency. The advent of these materials for solar applications has led to widespread interest in understanding the key enabling properties of these materials. This has resulted in renewed interest in related compounds and a search for materials that may replicate the defect-tolerant properties and long lifetimes of the hybrid lead-halide perovskites. Given the rapid pace of development of the field, the rises in efficiencies of these systems have outpaced the more basic understanding of these materials. Measuring or calculating the basic properties, such as crystal/electronic structure and composition, can be challenging because some of these materials have anisotropic structures, and/or are composed of both heavy metal cations and volatile, mobile, light elements. Some consequences are beam damage during characterization, composition change under vacuum, or compound effects, such as the alteration of the electronic structure through the influence of the substrate. These effects make it challenging to understand the basic properties integral to optoelectronic operation. Compounding these difficulties is the rapid pace with which the field progresses. This has created an ongoing need to continually evaluate best practices with respect to characterization and calculations, as well as to identify inconsistencies in reported values to determine if those inconsistencies are rooted in characterization methodology or materials synthesis. This article describes the difficulties in characterizing hybrid lead–halide perovskites and new materials and how these challenges may be overcome. The topic was discussed at a seminar at the 2015 Materials Research Society Fall Meeting & Exhibit. This article highlights the lessons learned from the seminar and the insights of some of the attendees, with reference to both recent literature and controlled experiments to illustrate the challenges discussed. The focus in this article is on crystallography, composition measurements, photoemission spectroscopy, and calculations on perovskites and new, related absorbers. We suggest how the reporting of the important artifacts could be streamlined between groups to ensure reproducibility as the field progresses

Improving the Method of Blasting Parameters Calculation in Construction of Horizontal and Inclined Excavation, for Example Mines of the Polar Division “Norilsk Nickel”

Статья посвящена актуальной на текущий момент задаче повышения эффективности буровзрывных работ при строительстве горизонтальных и наклонных подземных горных выработок. Предложена методика расчёта параметров буровзрывных работ при проведении горных выработок, базирующаяся на достоверном определении основных зон действия взрываThe article is devoted to the task today to improve the effectiveness of blasting during construction of horizontal and inclined mine workings. Proposed method for calculating the parameters of blasting during mining, which is based on the reliable determination of the main areas of action of the explosio

Dynamic Quality Management System Mineral

Статья посвящена решению вопросов повышения эффективности отработки месторождений многокомпонентных руд за счет внедрения современных средств и способов управления качеством руд при подземной добыче. Освещены новые пути обеспечения требований потребителей к качеству рудоминерального сырьяThe questions of increase work efficiency on the deposits of multicomponent ores due to the introduction of modern means and management methods. Highlight new ways of customer requirements to the quality of raw materials or

Improving the Method of Blasting Parameters Calculation in Construction of Horizontal and Inclined Excavation, for Example Mines of the Polar Division “Norilsk Nickel”

Статья посвящена актуальной на текущий момент задаче повышения эффективности буровзрывных работ при строительстве горизонтальных и наклонных подземных горных выработок. Предложена методика расчёта параметров буровзрывных работ при проведении горных выработок, базирующаяся на достоверном определении основных зон действия взрываThe article is devoted to the task today to improve the effectiveness of blasting during construction of horizontal and inclined mine workings. Proposed method for calculating the parameters of blasting during mining, which is based on the reliable determination of the main areas of action of the explosio