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By J. Alatalo

Autogenous grinding is a process of reducing the particle size distribution of an extracted ore by using the ore itself as the grinding media. It is a process that is difficult to control and there is a lack of knowledge of the events occurring inside the mill. To find out more about how the mill behaves under different processing conditions, a full factorial test was performed with iron ore in a pilot-scale pebble mill at the LKAB R&D facility in Malmberget. To complement this work, a strain gauge detector was embedded in one of the mill?s rubber lifters, the Metso Minerals continuous charge measurement (CCM) system, and was used to get more information about the charge dynamics. The data from the experiments has been analyzed. For production purposes, an increase in the number of particles smaller than 45 µm can be regarded as a probable increase in the production rate. The analysis shows that there will be an increase in fines at 65% of critical speed, especially when the mill is 45% full. This setting will also increase the power consumption, but improves the grindability of the ore even more. The deflection of the lifters is smaller for lower critical speeds. A higher degree of filling also gives a smaller toe angle and a higher shoulder angle as expected.

Nov 1, 2011

By S. C. Sun

Very little information is available concerning the magnetic properties of minerals and only recently has there been any attempt to correlate magnetic susceptibility with varying chemical composition1. The work described here covers a study of the relationship and chemical composition of both the rutile and sphene types of titanium minerals. The relationship between the magnetic susceptibility of three selected mineral specimens and the applied field strength is also presented. Experimental: The equipment and procedures used in this in- vestigation for crushing and cleaning the mineral specimens and for determining the magnetic susceptibilities were the same as that employed by Spokes and Mitchell1. The particle size of-the measured specimens was limited to 270/325 mesh.

Jan 1, 1959

By E. A. Rychkun

It is essential for a. mining company to determine an optimal mining strategy which will maximize the return on investment. In the case of Placer Development Ltd., the Lerch-Grossman three-dimensional optimization technique has been implemented on a digital computer to assist in the determination of such a strategy. It is the purpose of this chapter to explain and illustrate the methodology of the Placer Development Ltd. computer system with emphasis on the feasibility phase of a mine's development. In the Placer Development Ltd. strategy determination process, it is essential that certain objectives be considered: 1) There must be some means of constructing a realistic computer model of an ore body which gives a significant weight to geological constraints. 2) Data must be accurate and quantifiable. 3) Computer solutions must be unique, i.e., approximation or iteration methods of determining optimal solutions are undesirable. A method must be used which, when given fixed parameters and data, yields a mathematically sound unique solution. The following material is a presentation of how these objectives have been implemented. The flow of this outline will be from the general to the specific, with an example application.

Jan 1, 1979

By Steve Kral

"The mining industry is a tough business. The obstacles faced in attempting to run a mine - much less build a new one - go beyond an orebody’s geology. There was a time when commodity prices dictated whether or not to build or expand a mine. Today, though, the challenges faced by miners include social responsibility, environmental regulations and a myriad of needed permits on several governmental levels that every miner knows will be challenged by opponents every step of the way. With all of those challenges, and others not mentioned here, it’s a wonder anyone would stay in the industry. But they do. In fact, more than 2,100 mining professionals from around the world gathered in Reno, NV last December for the American Exploration and Mining Association’s (AEMA) annual conference. That is an impressive number, considering that commodity prices remain in the doldrums, preventing companies from building many new mines and limiting expansions at existing ones. Even so, attending such a conference allows these mining industry pros to learn new and more efficient ways to operate their mines and plants through the dozens of technical presentations the conference offered. And mingling with their peers provided another avenue for learning. The AEMA conference also attracted many of the industry’s leading equipment and service providers (228 exhibitors in 246 booths). Technical presentationsThe AMEA meeting is known for its variety of high quality technical presentations and the 2014 conference was no exception. Some of the topics include new technologies in surface and underground mining, explorers and emerging producers, mine closure and remediation, regulations and reserves reporting, hydrology and new innovations in mining. Here is a sample of some of the presentations."

Jan 1, 2014

By H. Tudeshki, A. Tayebi

"The large extent of global production and consumption of aggregates from quarries, grabs one´s attention and makes its substantial and essential standpoint in the world today pretty clear. A great amount of aggregates is utilized in civil engineering applications such as road construction, railway industry, concrete production, etc. Considering this fact that igneous rocks display a higher strength and abrasion resistance, this type of rock is preferred in the field of civil engineering. For all these applications, rock quality assurance is a key factor and certainly unavoidable, and it has great influence on the quality of constructions in civil engineering. One of the major problems encountered by both the producers and users of igneous rock is the fact that, with the passage of time, some specific rocks lose their strength, up to a complete loss of structure or in other words, their disintegration and degradation. In the last decades, different methods and procedures such as Glycol test, methylene blue dye test, as well as the Los Angeles test have been introduced to distinguish these rock properties, and to identify these problems. However, as these methods are time consuming, hard to perform, only to be applied to hand-piece samples, requiring special laboratory equipments, and only possible to be accomplished under laboratory conditions, their application has always been limited to some specific cases, and they are neither recommendable nor advantageous. In addition, these methods provide partially different results for the same rock. To address this widespread quality management problem of the quarry industry, a relatively quick, easy and user-friendly approach is necessary. It calls for a systematic solution with a device that can simply be used day to day in a mine for quality control of the quarry´s daily production. This scientific research is concentrated on developing a systematic method for early recognition and diagnosis of rock quality, in order to control and manage the quality of the quarry production in advance. This method was developed, based on the procedure of the magnetic susceptibility measurement. The obtained values can lead to valuable information regarding the quality of the rock and allows the quality control process to be accomplished and performed at the borehole location. This approach has been assessed through extensive field and laboratory studies. A detailed and comprehensive discussion will be made on the results of the experiments. The advantages and impacts of the application of this method, on increasing the reserves and environmental protection are also discussed."

Jan 1, 2011

By C. R. Daly, D. Biswas

This study presents the development of a simplified artificial neural network (ANN) for the characterization of rock mass with a simultaneous display of its output in a three-dimensional interactive environment as well as in the form of a text document. The system was developed using JAVA object-oriented language, virtual-reality modeling language (VRML) and JavaScript, and it runs on the Internet. The user can walk through a three-dimensional virtual roadway, checking the underground rock mass behavior and, consequently, can design a support system. The system first characterizes the rock mass with the help of a neural network and recommends a suitable support system for the particular geomining condition. The system then represents its output in a three-dimensional environment. The neural network developed in this system was trained with 261 data sets, and its performance was evaluated with five case histories. The evaluation results showed that the network could identify the rock category and support system adaptively. The average error for the support load was 2.7%. Among the five case histories, two were represented in a three-dimensional environment. The output obtained from the overall system compared favorably with the existing underground conditions.

Jan 1, 2003

By Jack M. Jodrey, Neil D. O’Donnell, R. A. Metz

Bituminous sands of the Lower Cretaceous McMurray Formation in northern Alberta constitute the ore for the surface mining operation at Syncrude Canada Ltd. These sediments represent a complex succession of fluvial, estuarine and marine depositional environments. Grade prediction is realized through a combination of geological interpretation, computer modeling, and reference to past mining experience. Accurate forecasts of feed grade permit reliable predictions of volumes for removal to meet budgeted synthetic crude oil production. This planning facilitates efficient allocation of mining equipment and resources. The feed grade to the Extraction Plant is monitored at various points along the delivery system.

Jan 1, 1992

By Scott G. Britton

Microcomputeranalysis has long been a technique for engineering professionals to improve the theoretical and practical design of continuous mining systems. Such work has been typically composed of modeling observed events and then introducing a variety of known elements with predicted results to compare against the results of the model. Programs written in BASIC, Cobol, Fortran or other language dominated such efforts. These programs have taken years to develop and prove out. This article explores a new management tool used daily at Tanoma Mining Co. (TMC) to track and improve continuous mining systems through the use of microcomputers and Lotus l-2-3 software. Data provided by section foreman, shift foreman, and maintenance personnel are analyzed against predetermined goals. In this way, new production targets are developed, weaknesses in the current mining systems are identified, and the results of changes are measured. The current results of this system on the productive output of TMC systems is on the order of 10% improvement. Thin seam coal mining is an industry within the broader industry of coal mining. Thin seam mining faces the same cost pressures and engineering problems as its higher-seam competitors without the advantages of moving volume per foot of extracted material to stay at an economic parity with others requires additional creativity within the management teams to extract higher productivity gains from the existing workforce and mining systems. TMC operates a deep mine in Indiana bounty, PA, about one hour northeast of Pittsburgh.

Jan 1, 1991

By A. O. Drysdale

From a mining point of view the Portland Cement Industry falls logically into the Industrial Minerals Division. Portland Cement manufacture requires four principal materials, lime, silica, alumina and iron. The usual source of lime is limestone. Silica sources include clay, shale, quartz, sandstone and sand. Alumina is usually provided by selecting a silica source with a suitable alumina content such as clay and shale. "Cement Rock" is occasionally found in which all four ingredients are found in natural combination or sufficiently close that only minor adjustments are required. In the absence of iron oxides a white cement can be produced. All raw materials used in Canada contain some iron and in most plants further minor quantities of iron are added to promote fluxing, hence the typical grey colour of Portland cement. The modern period in cement manufacturing started in 1824 when Joseph Aspdin of England patented a process for the manufacture of a modified hydraulic cement which he called "Portland Cement". Hydraulic cements are cements that harden under water. Although natural cements, made by calcining and grinding natural argillaceous limestone were produced in Canada as early as the 1830's, Portland cement was not produced in Canada until 1890, about 18 years after it was first made in the United States.

Jan 1, 1964

By S. Gaillard, E. Cauda

"Diesel particulate matter (DPM) is an occupational health hazard in underground mines. It generally occurs in the submicrometer size range and is often present in the mine atmosphere with significant concentrations of dust particles that tend to occur in the supramicrometer size range. As dust can interfere with analytical methods to measure DPM, it is often removed from a sample stream using an impactor-type size selector such as the DPM impactor (DPMI). Because the DPMI physically removes oversized particles from the stream, its performance may be gradually reduced with aging. Sharp-cut cyclones (SCCs) are an alternative size selector for DPM sampling applications, with a major advantage that, by design, they should not be susceptible to rapid aging. This paper presents the results of a field study designed to compare the performance of aged versus new/clean DPMIs and SCCs in an underground mine. DPMI aging resulted in clogging of the device and, eventually, a reduction of its effective particle cut size, but when sample flow rate was maintained, DPM sample mass collection was not affected until significant aging had occurred. Under the conditions of this study, the effects of SCC aging were observed to be minimal at the end of the study period. IntroductionSubmicrometer-sized particles are increasingly recognized as significant respiratory health hazards (Cantrell and Watts, 1997; Kenny, Gussman and Meyer, 2000; Ristovski et al., 2012). Diesel particulate matter (DPM) represents a major source of submicrometer particles in both public and occupational environments (Kittelson, 1998; Abdul-Khalek et al., 1998). Relative to other occupational groups, underground miners can have some of the highest DPM exposures due to their work in confined spaces where large diesel equipment is used (U.S. Environmental Protection Agency, 2002; Grau et al., 2004). DPM largely consists of solid elemental carbon (EC), commonly known as soot, and organic carbon (OC) that may be sorbed to EC particles (Kittleson, 1998; Abdul-Khalek et al., 1998). EC and OC can be measured by thermal-optical methods such as the U.S. National Institute for Occupational Safety and Health (NIOSH) 5040 standard method (Birch, 2016), and their sum is referred to as total carbon (TC). While the complex nature of DPM does not allow for its direct measurement, both TC and EC have been accepted as suitable surrogates for monitoring occupational exposures to DPM (Noll et al., 2007; Birch, 2016)."

Jan 8, 2018

By C. A. Holley

Agitative agglomeration is a rapidly expanding field related to many chemical processes. This paper reviews many processes and the particular type of agitative agglomeration that is utilized with each. Many new innovations to produce granular products in place of powder are explored. The operation and theory of the many types of agitative agglomeration equipment is reviewed.

Jan 1, 1988

By John E. Tilton

Mining is one of the oldest human activities. It goes back at least to the Bronze Age and possibly even the Stone Age. The Romans mined copper in Spain and tin in England some 2,000 years ago. The writings of Agricola in the 16th century show that mining was important in the Middle Ages. Today, more mineral commodities are mined in greater tonnages than ever before. This long and fascinating history closely tied with the economic development of the human race is one of the charms of the mining industry. It also, unfortunately, gives rise to some widespread misconceptions. Old industries are generally considered stodgy with mature and stagnant technologies. Costs tend not to decline as in newer industries, and may even increase with real wages. Costs are particularly expected to rise in the case of mining as the best mineral deposits are depleted. Thus, mining is often thought of as a sunset industry, destined to decline over time as the resource base is depleted. These perceptions have several important implications. They argue against economic policies that rely too heavily on mining and mineral processing to foster growth and development. The best and the brightest young people, along with society's other valuable resources, should be encouraged to enter newer industries. There the technological opportunities and the prospects for growth are more promising. These perceptions also suggest that the ability to compete in the mining industry depends largely on the quality of a company's or country's mineral deposits. Mining will take place first in countries with the lowest-cost deposits. Once these are exhausted, mining will shift to countries with the next best deposits. From time to time, new discoveries may also produce a shift in the location of mining, [ ] and may even for a time keep the costs and prices of mineral products from rising. Over the longer term, however, rising costs and prices are inevitable, as the world is forced to exploit poorer mineral deposits.

Jan 1, 1997

By P. Venkatraman, F. S. Knoll, W. S. Kow

Froth flotation is the most widely used technique for cleaning fine coal. This practice may change, however, with the development of enhanced gravity concentrators such as the Mozley Multi- Gravity Separator (MGS). The MGS is a flowing-film concentrator that utilizes centrifugal forces to improve the separation of flotation-size particles. In the present work, a pilot-scale test program was conducted to examine the effects of feed rate, feed solids content, wash water flow rate and drum rotation speed on the performance of the MGS. The test results indicate that the MGS effectively rejects high-density minerals such as pyrite, while ultrafine ash-forming minerals are removed less efficiently. A major advantage of the MGS is that high separation efficiencies can be realized without additional grinding, flotation reagents or heavy media. This article describes the working principles of the MGS and presents data obtained from recent pilot-scale test work.

Jan 1, 1995

By H. F. Hennigar, D. L. Pawson, E. J. Foell

Results of an analysis of abyssal benthic megafauna based upon review of nearly 250 hours of videotape and 2149 bottom photographs are presented, and the utility and limitations of such analyses in deep sea biological studies are discussed. The images were acquired at depths of 4400-4800 m during a resource assessment cruise aboard the RV Prospector using a unique, deep-towed, television telemetry system coupled with 35-mm photography. The data review was carried out in support of NOAA efforts to provide adequate environmental baseline information before industrial exploitation of nodule deposits and concurrent monitoring begin.

Jan 1, 1991

By Steve Kral

Despite low commodity prices and mining industry cutbacks throughout the world, Peru remains one of the industry’s bright spots. The country’s remarkable economic turnaround during the 1990s remains a model for other developing nations to follow. And the Peruvian government has not forgotten the industry that was instrumental in that turnaround. True, the country has not been spared the effects of the mining industry’s retrenchment that has occurred in other parts of the world. However, foreign mining companies remain committed to doing business in Peru. And the government remains committed to attracting foreign investment and maintaining a strong mining industry. This commitment was evident in September 1999during the 24th Convention of the Institutos de Ingenieros de Minas del Peru in Arequipa, Peru. More than 3,000 mining industry professionals from around the world attended the convention. And Extemin, the accompanying exhibit, featured more than 450 companies, many from the United States, Canada, Australia, South Africa and other countries.

Jan 1, 2000

By B. Morris

This presentation will describe the process by which the Quebrada Blanca (QB) copper project in northern Chile was financed. It will also show how a relatively junior mining company addressed the problems created by its inability to provide its share of the equity funding and the guarantees required by the project lenders. QB is located in the semi-arid Andean highlands of northern Chile, 170 kilometres southeast of the port of Iquique and 30 kilometres west of the border with Bolivia, at an altitude of about 4,300 metres (14,000 feet). Figure 1 depicts the project's location. The QB orebody is a secondarily enriched porphyry copper deposit containing reserves of 85 million metric tons grading 1.3 percent copper. Underlying the enriched zone is a significant primary ore zone containing several hundred million metric tons grading about 0.5 percent copper. In the late seventies and early eighties Falconbridge and its affiliates spent $20-30 million dollars exploring the deposit and conducting feasibility studies. For a variety of reasons they decided not to develop the property which was returned to its owners, Empresa Nacional de Mineria (ENAMI), which is a Chilean state mining corporation. In 1988 ENAMI announced its intention to privatize the property through a public bidding procedure.

Jan 1, 1993

By E. Watkins, V. Gangrade, P. Zhang, J. Addis, D. W. H. Su, T. Minoski, C. Hollerich, M. Van Dyke, S. Schatzel, H. Dougherty

"This paper presents the results of a comprehensive study conducted by the Centers for Disease Control (CDC), National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Mining Research Division (PMRD) to evaluate the effects of longwall-induced subsurface deformations and permeability changes on shale gas well integrity and safety under shallow cover. NIOSH researchers selected a study site over a southwestern Pennsylvania coal mine, which extracts 1,500-ft-wide longwall faces under 482 feet of cover. One in-place inclinometer well and three permeability monitoring wells were drilled and installed over a 125-ft by 275-ft centers abutment pillar. In addition to the inclinometer well and monitoring wells, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the first 1,500-ft-wide longwall panel on the south side of the abutment pillar mined by the site.A number of FLAC3D finite difference simulations (Itasca Consulting, 2017) were conducted to estimate surface subsidence, coal pillar pressure increases, and horizontal displacements in the in-place inclinometer (IPI) monitoring well. Comparisons of the FLAC3D finite difference simulation results and the surface, subsurface, and underground instrumentation results show that the measured IPI casing deformations are in reasonable agreement with those predicted by the FLAC3D models, and that the measured surface subsidence and underground pillar pressure are in excellent agreement with those predicted by the 3D models. Measured permeability changes were incorporated into a preliminary calculation to evaluate the effect of a hypothetical shale gas well leak on longwall ventilation. Results from this 2018 research clearly indicate that under shallow cover, the measured horizontal displacements within the abutment pillar are at least one order of magnitude higher than those measured in a 2017 study under deep cover and slightly higher than those measured in a 2014 study under medium cover. This research represents a very important step and initiative in utilizing the knowledge and science obtained from mining research to improve miner and public safety as well as the safety and health of the workers in the oil and gas industries"

Jan 1, 2019

By Carlos Henrique Turolla Maia, Ulrich Maidl, Marc Comulada, Julio Claudio Di Dio Pierri

"Pure sands are typically the domain of slurry shields due to their high permeability and their granular characteristics. However, the Earth Pressure Balanced (EPB) shield machine technology has advanced in recent years with improved conditioning agents and shield machines that are equipped with slurry injection facilities and alternative mucking methods. These new so-called hybrid EPB machines have steadily increased the range of application of the EPB technology. The contribution discusses the capacities and operational features of hybrid EPB vs. slurry shield technology in pure sands. At the example of the Metro Line 4 in Rio de Janeiro (Brazil), the contribution shows that hybrid EPB tunneling in pure sands is possible and it is compared with a state-of-the-art slurry shield project as the KASIG project in Karlsruhe (Germany). Furthermore, the control of the support pressure by means of foam conditioning and slurry injection in conjunction with a close, real-time monitoring of machine parameters is discussed. INTRODUCTION Slurry shield and EPB technologies have both undergone significant developments in recent years, leading to the use of parts of one technology in the other and even to completely hybrid systems. Also the ranges of application (see recommendations by DAUB (DAUB 2010)) of both technologies have been shifted far beyond their original limits and are largely overlapping by now. Nevertheless, the basic principles of face support remain unchanged. Exploiting the possibilities of process data analysis (Maidl 2014), the interactions between the ground and the shield machine are a matter of research and have been intensely investigated. PRINCIPLES AND CALCULATION OF FACE SUPPORT PRESSURE Figure 1 shows the principles of two approaches for the determination of required support pressures: kinematic methods and numerical methods. Kinematic methods that are employed for the assessment of face stability only consider the situation in front of the TBM. The required face support force is determined by means of an assumed failure wedge that would form in ultimate limit state. Based on the ground properties, the vertical surcharge and the self-weight is transformed into a horizontal force along a virtual sliding surface. This horizontal force is to be balanced by the face support. The calculation results are amended by respective partial safety factors for water and earth pressure and the method-specific support pressure fluctuations are added."

Jan 1, 2016

By S. Uihteenmaki

Pyhasalmi is a massive sulfide orebody located in central Finland. The mine has been in operation since 1962. The flotation concentrator produces Cu, Zn, Pb and pyrite concentrates. The plant has used an on-stream analyzer for process control since 1968. The original analyzer has overlived a few generations of minicomputers, but the analytical parts are essentially unchanged. The on-stream analyzer is a critical component in plant process control system, which has made Pyhasaltni one of the pioneers in the art of computer control and optimization of flotation plants. The paper summarizes the experiences gained from the use of the high performance elemental analyzer system and the proven benefits from the use of on-stream analyzers at a complex sulfide flotation. The aging analyzer is approaching the end of its useful life. A new state of the art analyzer system is undergoing testing at Pyhasalmi.

Jan 1, 1999

Information Technology has addressed those problems unique to senior management in the mineral industry. In general, these problems are those concerned with decision-making. Peter Drucker in his discussion of making effective decisions identifies five phases: (1) define the problem, (2) analyze the problem, (3) develop alternate solutions, (4) decide the best solution, and (5) convert the decision into effective action. The scope of the chapter by Guernsey addresses the first three phases which provide input to the decision-maker. The decisions to be made relate, in most instances, to the economics related to a mineral property or process. Computer models have been designed to generate these economic and financial evaluations. No one model is appropriate to the solution of all management's problems. In this chapter several applications are identified and summarized; a model for the economic evaluation of a mineral property is described in greater detail. The implementation of such models is dependent on the unique needs of management.

Jan 1, 1979