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By Oliver C., Ralston

THE following data were obtained during Tan exhaustive research into the possibilities of concentrating United Verde massive sulfide copper-zinc-iron ores by flotation. The composition of these ores approximates the following mineralogical analysis: 3 to 15 per cent chalcopyrite; 3 to 11 per cent marmatite (ferruginous sphalerite) ; 47 to 69 per cent pyrite; and 10 per cent quartz. The remainder is usually schist gangue. The sulfide minerals are finely dis-seminated; chalcopvrite and marmatite begin to be liberated on grinding at about 100 mesh, but complete liberation from gangue (pyrite in this case is considered a gangue mineral) is

Jan 1, 1935

By L. Hales

Neural networks are a generalized, multivariable non-linear modeling technique that can be used to model mineral processing operations. Neural networks will be described as will their use in modeling column flotation. Optimization of column flotation will be explored and discussed by using the neural network column models.

Jan 1, 1996

By W Z. Liu, Q Q. Shi, H T. Yang, X L. Zhang

In order to improve the cutting blasting effect of dimension stone mining, the water coupling directional cutting blasting technology was put forward. Based on the test apparatus and special charge configuration, the mechanism of directional cutting blasting was analysed. Directional device changes the initial equilibrium of the total energy of shock wave effect on blasthole wall. The initial directional crack first appears in the blasthole wall that makes contact with the directional device. Then, two cracks are connected along the direction of the blasthole centre line under the action of detonation pressure and water wedge. The plexiglass tests showed that water coupling directional cutting blasting technology produced cracks along with the predetermined direction completely. The cutting surface was smooth and only a few short cracks appeared around the blastholes. It proved the validity of this technology.CITATION:Liu, W Z, Zhang, X L, Yang, H T and Shi, Q Q, 2015. Directional blasting rock cutting technology, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 815–818 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By W. F. Netzeband

Jan 1, 1927

By Guangming Zhao, Nianjie Ma, Demao Guo, Denghong Chen, Yingming Li

Based on the mechanical essence that large-scale plastic failure zone appears in all or part of surrounding rock in soft rock roadway, the numerical simulation method is used to study the rectangular roadway in layered rock strata. It is clarified necessary conditions must be met for soft rock: firstly, the strength condition is that the maximum confining pressure is greater than the uniaxial compressive strength of rock strata. Secondly, the stress environment condition is that the ratio of maximum confining pressure to minimum confining pressure is greater than 3. Thirdly, the angle condition is that The direction of principal stress action enables the plastic zone of weak rock layers to fully develop. At the same time, the quantitative description method of soft rock is given, and the soft rock roadway is redefined. Soft rock roadway refers to the roadway that meets the strength conditions, stress environment conditions, and rock structure angle conditions under certain surrounding rock conditions and in-situ stress environment conditions. After the excavation of the roadway, a large-scale plastic failure can be formed, that is, a butterfly-shaped plastic zone is formed, and the conventional support cannot be adapted. It is difficult to support in engineering. It provides a theoretical basis and engineering analysis method for the identification of soft rock roadway, and the research results have engineering value Soft rock tunnel engineering in coal mines constitutes a vital aspect of soft rock engineering. This field broadly encompasses rock engi- neering concerning large plastic deformations, e.g., soft rock slope engineering and soft rock tunnel engineering. The intricate geological conditions encountered in soft rock tunnel engineering present a significant challenge to support, which has harmed coal production in China. China leads global raw coal production with the annual output of 4.6 billion tons. Annual tunnel excavation supporting this production spans approximately 11,000 km, with over 10% of these tunnels classified as soft rock formations. Soft rock is commonly associated with soft rock tunnels due to their prevalence in engineering projects. However, reaching a consensus on the definition of soft rock has long been an enduring challenge for scholars and engineers. Numerous definitions have been proposed, includ- ing descriptive, index, and engineering definitions. For instance, the International Society for Rock Mechanics defines soft rock based on its uniaxial compressive strength σ ranging from 0.5 to 25 MPa. China's Engineering Rock Body Standards, established in 1994 (GB 50218-94), take a qualitative and quantitative approach to classifying rocks. Rocks are categorized as hard or soft based on criteria such as hammering sound, fragmentation, water immersion effects, and weath- ering degree. Additionally, the integrity of rock bodies is assessed across five categories intact, relatively intact, soft fractured, fractured, and extremely fractured. This classification considers factors like the number and spacing of structural planes, their combination, and the types of structures. Descriptive and index-based definitions fall under the category of geological soft rocks, providing a comprehensive geological perspective on the surface features or strength characteristics. However, these definitions have limitations in engineering practice, which leads to contradic- tions. For instance, rocks with uniaxial compressive strength less than 25 MPa may not exhibit soft rock characteristics if the tunnel is shal- low with low horizontal stress levels. Conversely, rocks with compressive strength exceeding 25 MPa at sufficient depth and high horizontal stress may exhibit soft rock characteristics. Definitions originating from engineering practice have emerged after realizing the inadequacy of discussing soft rocks without considering engineering. For instance, Dong's loose circle theory defines soft rocks as rocks with a loose circle thickness exceeding 1.5 m, which chal- lenges conventional supports. This intuitive definition, widely accepted by engineering professionals, emphasizes the difficulty in supporting tunnels due to extensive damage. However, various tunnel damage poses a challenge in relying solely on the loose circle thickness of tunnels for determining soft rocks. He introduced the concept of engineering soft rocks, which are defined as rock formations exhibiting significant plastic deformations under applied engineering force. Two fundamental mechanical properties of soft rocks are identified the critical softening load and critical soft- ening depth. Rocks below the critical softening load threshold are categorized as hard rocks, while those exceeding it exhibit substantial

Jun 25, 2024

By R. L. Castro

Block caving methods, when operated under favourable rock mass conditions, can achieve higher production rates and lower operating costs than other various existing underground mining applications. For this reason, it has been considered the preferred method for the mining of deep and large orebodies in current and future operations around the world. One of the key aspects in the design of block caves is the selection of the production level layout, which, among other parameters, is based on the gravity flow characteristics of the caved rock. This is because gravity flow has a large impact on total ore recovery and the amount of dilution in a caving operation. Today, there are a number of computer based methods which aim to emulate the gravity flow pattern of the caved rock. In this paper, the authors present the development of FlowSiman improved model of gravity flow based on the cellular automaton approach, to estimate dilution entry, mixing and ore recovery. As part of the model development, flow simulations were conducted and subsequently compared to full-scale data collected at two mine sectors operated by Codelco Chile. The results indicate that by using proper calibrated parameters, good correlations between simulated and measured grades as well as dilution entry are obtained. The potential use of the numerical tool to evaluate drawpoint spacing in terms of recovery and dilution for block/panel caving operations is also presented.

Jan 1, 2009

By R. A. Hill, J. D. Pitts

"Long distance slurry pipeline systems have been successfully trans-porting steam coal, iron concentrates, copper concentrates and limestone for an aggregate of nearly 60 years and nearly three billion ton-miles annually. A phosphate concentrate pipeline is nearing start-up and systems for coking coal, lead/zinc concentrates and fly ash are planned. The solids pipeline concept, first patented in the early 1900's and commercialized in the 1950's, is now a proven technology providing an economic, environmentally pleasing and safe method for long distance bulk transport.The challenge for larger tonnage and longer distance movements of solids, for traversing increasingly rugged terrain in grass roots mineral developments, for transporting untried materials and for shipping more economic forms of proven materials still remains. This has necessitated continued refinements and optimization of the technology. The economic and environmental incentives for slurry pipelines when compared to other transport alternatives has justified substantial activity in this area. The scope of planned systems in coal, iron and other minerals is indicative of the firm place slurry pipelines will have in worldwide mineral development.In this presentation, the state-of-the-art in long distance slurry pipelines is reviewed with a focus on major systems of interest to the mineral processing industry. An overview of new developments in the application of this concept is presented, and finally, a projection of the future of pipelines in mineral development both worldwide and in Canada is discussed."

Jan 1, 1978

ABSTRACT Based on mineralogical characteristics and processing techniques required, gold ores can be classified into 12 types: gold placers, quartz vein-lode ores, oxidized ores, silver-rich ores, iron oxide copper-gold ores, porphyry copper-gold ores, iron sulphide ores, arsenic sulphide ores, antimony sulphide ores, bismuth sulphide ores, telluride ores, and carbonaceous sulphide ores. The bulk mineralogy and gold deportment of each ore type differs and may have a significant impact on ore processing and metal extraction. This paper summarizes the bulk mineralogy and gold deportment in some major types of gold ore and discusses the potential impact of gold deportment on gold metallurgy.

Jan 1, 2013

By M. W. Wadsley

"Physical and chemical property models are widely used in process engineering. There exist, in the published literature, completely empirical models of ''thermodynamic properties"", that is, property models that are not consistent with the laws of thermodynamics. There also exist property models that purport to be thermodynamically consistent but are flawed in their implementation. There are also published property models that are consistent with the laws of thermodynamics but that do not reproduce property values with an acceptable accuracy. A practicing engineer might be asked to assess very different property models for which there are a variety of claims. This paper discusses features of thermodynamic and empirical property models that may assist in their practical evaluation and implementation."

Jan 1, 2005

By Elaine T. Cullen

Underground mining, like many high-risk industries, is facing a crisis in the near future. This industry has traditionally relied on a master-apprentice relationship to train new workers, but experienced miners are retiring in large numbers, leaving few "masters" to properly train their replacements. With a recent resurgence in mining, many new miners are entering the workforce each day. The rise in the number of inexperienced workers has implications for worker safety in an industry in which one mistake can blow up the entire workplace. The explosion in the Darby Mine in May 2006 that killed five miners illustrates what can happen in hazardous environments such as underground mines. The Health Communications Team at the National Institute for Occupational Safety and Health Spokane Research Laboratory was asked to address this problem by developing new training and safety awareness materials to promote safe flame cutting and welding practices. This article describes how occupational ethnographic techniques provided insights needed for "new product development." The result of this work was a national initiative to raise awareness and to protect underground coal miners from the dangers of flame cutting and welding in an environment filled with solid fuel and methane (natural gas). Although this project was initially designed for the mining industry, the approach and lessons learned are applicable to any high-risk industry and should be of interest to other social marketing or occupational safety and health professionals.

Jan 1, 2009

By Thomas J. Menner

Jan 1, 1983

By M A. Harrington-Baker, J M. Trudnowski

Sulfate-reducing bacteria (SRB) have the ability to immobilise dissolved metals by precipitating them as sulfides, provided that a favourable biochemical environment is created. Such an environment includes the presence of sulfate, anaerobic conditions and the availability of organic carbon. If such conditions are engineered within a reactive barrier or field-bioreactor, most metals can be effectively removed. To demonstrate this concept, three passive SRB field-bioreactors were constructed in 1998 at an abandoned mine site in the vicinity of Butte, Montana, USA to treat acid mine drainage with characteristic elevated concentration of metals and low pH. Performance of the field-bioreactors, using aqueous samples, was monitored over 32 months until the project was terminated, field-bioreactors were decommissioned and solid matrix sampling of the reactive matter was performed. The most important analytical results are presented in this paper together with conclusions regarding the appropriateness of the field-bioreactors construction features. Only Zn, Cu, and Cd were being removed as sulfides due to SRB activities. Changes in concentrations of other metals (Fe, Mn, Al, As), which do not necessarily precipitate as sulfide, seemed to be affected by SRB only in an indirect manner by responding to increased pH caused by SRB activity. An innovative cellular containment system used for placing organic matter worked very well in preventing settling of the organic matter and ensuring uniform flow of AMD throughout the entire cross-section of the organic carbon with no preferential flow paths This demonstration was funded by the US EPA and was jointly administered by the EPA and the US DOE under DOE contract number DE-AC22-96EW96405. The project was implemented by MSE Technology Applications, Inc, Butte, Montana, USA.

Jan 1, 2003

By D. E. Munson

The Waste Isolation Pilot Plant (WIPP) Project was established in 1975 by the Department of Energy (DOE) under Public Law 193 to develop the necessary technology for safe disposal of radioactive wastes from the defense programs of the U.S. The technology development involves extensive theoretical, numerical, and laboratory programs, as well as construction of the WIPP facility in southeastern New Mexico for in situ testing and waste storage demonstration. If after the demonstration, the facility is found to comply with regulations of the Environmental Protection Agency, then the facility will become a repository for Transuranic (TRU) waste. The underground portion of the facility is 655 m beneath the ground surface in massive natural salt deposits of the Salado formation, as shown in Figure 1.

Jan 1, 1991

By C. M. Brinckerhoff

Much has been written in the mining technical magazines about the caving system. Many of these articles were published in the Transactions of the American Institute of Mining Engineers prior to World War II. In recent years little has been written on mining methods or on the detailed planning always required. Block caving had primarily been used to mine deep copper ores in Africa, the United States and in Chile, although other ores had been mined by this same system. Asbestos ore had been caved in Canada, tin ore in Bolivia, molybdenum ore in Colorado, iron ore in Wyoming and Sweden, and limestone in California.

Jan 1, 1984

By Zhiwei Wang, Chunsheng Qiao

"Aiming at the problems of the existing calculation methods for the support pressures of shallow tunnels in layered jointed rock strata, by using OAT (orthogonal array testing strategy) and DEM (distinct element method), 12 influencing factors including the thickness of the weathered overburden, and the states of the rock joints were considered. Then, the classification of the loosening zone was analysized. On this basis, by using the DEA (data envelopment analysis) theory, quantitative analysis on the influencing factors was conducted. By analyzing the influence of the key factors, a prediction formula of the boundary of the ringent trumpet-shaped loosening zone was established. According to principles of stress transformation, the formula of support pressures of the loosening zone which could considering the key factors were deduced. Finally, a practical case was introduced and studied to verify the proposed method.INTRODUCTIONIn recent years, various urban subway tunnels are increasingly carried out through jointed rock strata in many cities. Rock masses are discontinuous mediums with fissures, fractures, joints, bedding planes, and faults. The frequency of joints, their orientation with respect to the engineering structures, and the roughness of the joint have a significant importance from the stability point of view. However, there is a lack of understanding about the influence of the joints on the stability of tunnels. Therefore, how to measure the degree of the joints’ influence is a problem that needs to be solved.For the calculation of the support pressures, until now, many research results were focused on soil ground (Bierbäumer 1913; Terzaghi, 1943; Peck, 1969; Sabatini et al., 1999). In terms of site tests and model indoor tests, by measuring strut loads and calculating earth pressure based on strut spacing, the results proposed by Peck (1969) and Tschebotarioff (1973) have been widely used in practice for designing excavation support systems under sand (drained) and clay (undrained) soil conditions. Note that, it is unclear whether these findings could be extended to rock strata. For numerical simulations, how to simulate the states of the rock joints is a key problem that needs to be solved."

Jan 1, 2015

By D. Beneteau, D. Milne

"Advances in technology provide educators with valuable tools to enhance their teaching and efficiently deliver content to larger audiences. University educators are often encouraged to become more “research intensive” and to increase student enrollment. Faced with these pressures, there is a tendency to use technology to improve teaching efficiencies rather than to enhance existing teaching approaches. Practical learning in applied engineering courses would suffer greatly if hands-on experience is not emphasized. This paper discusses advantages and limitations of new technologies applied to learning, and methods to incorporate more hands-on experiential teaching techniques to applied mining engineering courses.RÉSUMÉ Les avancées technologiques fournissent aux éducateurs des outils intéressants pour rehausser leur enseignement et livrer efficacement de la matière à de grands auditoires. Les éducateurs universitaires sont souvent encouragés à devenir plus « axés sur la recherche » et d’augmenter l’inscription d’étudiants. Face à ces pressions, il y a une tendance à utiliser la technologie pour améliorer l’efficacité d’enseignement plutôt que de rehausser les approches existantes d’enseignement. L’apprentissage concret dans les cours d’ingénierie appliquée souffrirait grandement si l’accent n’est pas mis sur l’expérience pratique. Le présent article discute des avantages et des limitations des nouvelles technologies appliquées à l’apprentissage et des méthodes pour incorporer plus de techniques expérimentales pratiques aux cours de génie minier appliqué."

Jan 1, 2016

By Welby G. Courtney

The Bureau of Mines conducted an exploratory field survey to determine the amount of airborne coal dust, the size distribution of the dust, and the rate of dust deposition in coal mine airways. The survey was taken at eight underground locations in operating coal mines. The rate of dust deposition in the airways depended upon the concentration of air-borne dust and decreased exponentially with distance from the dust source. The rate was seemingly independent of the size of the airborne dust particles. The rate of deposition, along a return, for the coal dust from a fade being mined with a continuous mining machine closely matched the rate for the rock dust from a trickle duster. A sample rock-dusting schedule for that return is presented; that is, the trickle duster should be operated for 3-112 hours after every five shifts to protect the average deposit of new float coal dust in the return, but operation after every three shifts is preferred, to protect an occasional heavier deposit.

Jan 1, 1982

"Many industrial processes involve materials that are subject to temperature change and thermal stress. Examples range from the casting of large metallic products to the cooling and reliability of small electronic components. Thermally induced stress is a major concern as it can lead to material damage and product failure. Material properties, thermal and mechanical, and process conditions such as the size and location of a feeder in metals casting, or the power dissipation in a computer chip, will govern the magnitude of these stresses. Temperature may also be influenced by fluid flow, for example, the airflow over a computer chip in a laptop will govern the rate of heat extraction, hence the temperature gradients in the chip and the evolving thermal stresses.This paper provides details on the governing equations for heat transfer (temperature) and solid mechanics (stress), their degree of coupling, and the numerical techniques used to solve them. Three examples are discussed to illustrate the use thermomechanical modelling. These also provide an insight into the degree of coupling required between the equations. The first example, involves thermal cycling of electronic components where a prescribed temperature field is applied. As temperature is known, this example only requires the solution of the stress equation. The second example also involves the modelling of an electronic component where the temperature field is also calculated. In both of these examples, the stress calculation is dependent on the temperature field, but the temperature calculation is not dependent of the solution of the stress equation (one-way coupling). The final example provides details on modelling the metals casting process. Both the temperature and stress equations are solved but, unlike the previous two examples, in this case the temperature field is dependent on the results from the stress calculation (two-way coupling)."

Jan 1, 2001

"Use of the Bond Work Index to size industrial grinding equipment was widely known. Bond also described its application for measuring grinding circuit efficiency. Bond Work Index efficiency has been widely used by industry, but until now without concise standard methods, or a formal guideline, for doing so. The Bond Efficiency Sub-Committee of the Industrial Comminution Efficiency work group of GMSG has produced such a guideline, which follows. It covers the methods and provides examples of how to calculate the Bond Work Index Efficiency of most industrial grinding circuits. Bond Work Index testing equipment and methods are also provided. The next steps are: (1) to establish standard reference testing materials and one or more laboratories to serve as bases for reference testing; (2) to establish the accuracy of relative circuit Work Index Efficiency determinations; and (3), to develop and provide a public data base of industrial comminution circuit Bond Work Index Efficiencies. OUTLINE Introduction and Background Part 1. Determining the Bond Efficiency of a Grinding Circuit Method Demonstration/Example Calculations Bond Work Index Testing Equipment and Procedures Accuracy of Comparative Circuit WI Efficiency Determinations (under development) List of Symbols Part 2. Data Base of Bond Grinding Circuit Efficiencies (under development) References Annexes: A1. The Bond Crushing WI Test Equipment and Procedure for Bond Efficiency Determinations (Revised March 26, 2015) B1. The Bond Rod Mill WI Test Equipment and Procedure (Revised March 26, 2015) C1. The Bond Ball Mill WI Test Equipment and Procedure (Revised March 26, 2015) Introduction and Background Please see the references and slide presentation “Bond Efficiency SLC (rev3)-print.pdf.” This efficiency determination applies to most brittle materials in their naturally occurring (un-scalped) size distributions being treated in size reduction circuits down to a product sizing of approximately eighty percent passing 70 µm (see below). Unusually shaped materials (e.g. mica) should be regarded with caution. Part 1. Determining the Bond Efficiency of a Grinding Circuit Method In the plant: • Define the circuit for which the WI efficiency is to be determined • Procure samples of the circuit feed and product • Obtain the power draw of the size reduction equipment at the drive pinion(s) • Obtain the circuit throughput rate (dry tonnage) In the laboratory:"

Jan 1, 2016

By J. E. Klein

Bench scale tests using a stack of ten whole SAES St909 pellets, 6 grams, to crack methane have been completed with pure methane feed. Test conditions ranged from 600 to 800°C at 101 kPa (760 ton) with a methane feed rate of ten sccm. Methane reformation tests, test where hydrogen was passed through a St909 bed after cracking methane, were performed to determine if and how much methane can be generated under "reformation" conditions. Phase structure determinations of St909, composed of a ZrMnFe alloy with aluminum used as a pellet binder, after methane cracking were complicated by the number of materials that can be formed by the elements in the St909 and the carbon from methane cracking. It was determined that the aluminum not only alloys with the Zr, Mn, and Fe in the St909 alloy, but also forms aluminum transition metal carbides in addition to ZrC as the carbon content and the temperature of the St909 increases. Some A14C3 was also found in some pellets. Passing hydrogen over St909 pellets after methane cracking formed methane at various rates in the temperature range of 600 to 800°C. Temperatures of 800°C gave the best methane cracking performance and efficiencies decreased rapidly with temperature.

Jan 1, 2002