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By D. Brunner

System simulation is an increasingly popular technique for analyzing and improving existing as well as newly designed underground mining operations. An engineering firm that specializes in simulation helped a major metals producer build a long-range planning model of an existing underground mine. Subsequently the team adapted this model to assess technology alternatives in the design of a new mine. The two models differ in the level of detail used for modeling the development process. This paper discusses the differences in approach between the models along with the experiences gained and challenges faced during the construction and use of the models.

Jan 1, 1999

By Ron F. Schritt

Over the many years since the development of the steam powered shovel, various powering and control techniques have been employed for the various shovel functions. While volumes have been published on this subject, this paper will be limited to a very brief discus-sion of one of the latest of these and its application to a unique machine. The evaluation of the subject machine is far beyond the scope of this discussion, which will be limited to the techniques and equipment employed, and the considerations involved in their choice. The basic requirements for any power and associated control system for any power shovel function have remained relatively un-changed over the years. To the extent possible, such an equipment grouping must be: Easy to install during fabrication Easy to maintain and repair by available personnel Life cycle cost competitive Adequately reliable Adequately responsive And as may be expected these factors are arranged in various orders of priority by different manufacturers and users. All the various time honored approaches have to some extent fulfilled these require-ments but were discarded or fell into disuse when more effective approaches were developed. The latest in this long line of develop-ments and perhaps the most promising is that of electro-hydraulic controls and hydraulic drive.

Jan 1, 1977

By H. Wesley Peirce

Arizona embraces portions of two major western-U.S. physiographic-geologic provinces and a smaller, local one. These exert fundamental control over the geologic framework and associated earth-material resources and potential. The Mogollon Rim diagonally crosses the State and separates the Colorado Plateau Province to the northeast from the Transition Zone and Basin and Range Province to the southwest. More than 90 percent of the population, production of nonfuel minerals, agricultural land, and water resources are in the Basin and Range part of the State. In 1981 Arizona was ranked number one in the Nation with respect to the value ($2.56 billion) of nonfuel-mineral production. About 8.2 percent of this amount ($212.9 million) can be attributed to nonmetallic (industrial) materials. Although a diversity of nonmetallic substances is produced and some are exported, the bulk is utilized within the State and is directly related to market growth. Since 1950 there has been a fourfold increase in Arizona's population, a concomitant twelvefold jump in sand-gravel production (tons), and a twentyfold increase in "stone" production. New industries developed during this time include cement, salt (and storage of liquid petroleum gas products in solution cavities in salt), zeolite, hydrofrac sand, vitrified clay pipe, crushed marble products (teed additive, pool sand, roofing granules, etc.), and "rock" wool. Most of these newer industries serve out-of-State as well as in-State markets. In 1981 at least 225 industrial mineral or rock deposits were being worked to produce about 10 tons of material per Arizona resident per year. In 1980 the relative values of basic industrial minerals produced in the State, by major group, were cement and lime (51.6 percent); gravel (26.5 percent); sand (11.8 percent); stone (4.6 percent); and others (5.5 percent). Detailed knowledge of the nonmetallic rock-and-mineral content of most Arizona ranges and basins is lacking. Exploration opportunities in this sun-belt growth region appear encouraging.

Jan 1, 1987

By M. Spangler

FirstMiss Gold installed a supervisory control system based on Pavilion Technology's Process Insights neural network software and Oil System's PI data historian. The primary goal of the system was to control the acid preconditioning circuit. However, our first successful control loop was on the limestone feed rate to the neutralization circuit. The information gained by modeling these circuits and the better control provided by the system has resulted in reagent savings of over $80,000 per month.

Jan 1, 1995

By R. Adsero

"In view of the decade long decline in worldwide mine equipment productivity and with heavy economic pressures and survival at risk, improvements for those remaining in the game are essential. The latest Multifactor Productivity data for the US mining industry indicates a continuing descent with Australia on a similar course. The world’s mining industry has a fleet of over 400 large draglines moving billions of tons of material annually. The most efficient use of this equipment resource will provide a competitive advantage to those companies who are committed to improving performance. A dragline monitoring system is a requirement for optimum operations. The monitor reports the facts. Focused actions can change the facts and create improved performance. Analyzing monitor data to build knowledge and create understanding is a beginning. Understanding the key productivity indicators for dragline operations and an effective benchmarking process are the basis for improvement. There is overwhelming evidence that adopting new technologies and concepts including AC drive technology can and will bring about a step change in dragline operating cost with improved production performance.STATE OF THE MINING INDUSTRY A high altitude review of the state of the mining industry provided by a study of multifactor productivity shows a continuation of lower and lower output year on year for the capital and labor inputs applied. The story is sadly similar for both U.S. mining and the Australian mining sector. In fact, according to PwC analysts the worlds mining equipment productivity has declined 20% over the past seven years. (Lumley, 2014) Although the reasons for the continuing decline in mining productivity are varied, the need for improvement is clear. The world’s mining industry fleet of well over 400 large draglines moves billions of tons of overburden and ore (phosphate, limestone, etc.) annually.This discussion will review a few of the tools available for improved productivity in dragline operations."

Jan 1, 2016

By C. V. Deutsch, D. A. Silva

The geologic modeling of multiple domains is required for the prediction of mineral resources and reserves. In general, explicit methods have wide acceptance among modelers due to the ability to manually add deemed important trends and geological features into the models. As an alternative, implicit geologic modeling techniques are increasingly adopted to reduce professional time requirements. These methods aim for objective, repeatable and flexible models by replacing the manual time-consuming interpretation of sections with the interpolation of signed distance values. These techniques, however, have been developed for the binary case of two domains at a time. The current paper presents an algorithm that extends the binary case to multiple domains. The method is able to transfer large-scale geological features from data to geologic models. A case study illustrates the benefits of the algorithm and practical implementation considerations.

Jan 1, 2016

By R. S. Conti, M. R. Krump, C. P. Lazzara Ph. D., R. L. Derick, L. L. Chasko

A mine fire is one of the most challenging safety issues facing a mine operator and can occur at any location underground. The National Institute for Occupational Safety and Health (NIOSH) and the Twentymile Coal Mine, CO, conducted in-mine experiments to determine the capability of high-expansion foam for addressing underground fires. The tests were conducted in sloping entries with high-capacity diesel-powered foam generators. The following results were observed: a well-designed, maintained and properly operated high-expansion foam generator can propagate a foam plug hundreds of feet in steep upward-sloping (20%) multiple entries against a ventilation pressure; stoppings and partitions designed to contain the foam plug in upward-sloping entries must be substantially constructed; and the predicted quantity of foam concentrate can be significantly less than the actual amount used, due to foam losses, such as bubble breakage on dry surfaces. This paper describes the production of high-expansion firefighting foam and discusses the in-mine experimental tests and results.

Jan 1, 2010

By B. A. Carbon

Western Australia is the largest state in Australia with an area one and three quarter times the size of Texas. Most of the State is desert or semi-desert, and only the southwest corner is heavily populated. The State has a population of one and a half million people, and one million of these live in and around the city of Perth. Perth is located on the narrow Swan Coastal Plain and is flanked by the Indian Ocean and the Darling Plateau. The Darling Plateau is an ancient peneplain rising some 300 metres above sea level, and forms an important resource base for the population.

Jan 1, 1984

The 2012 North American Tunneling (NAT) conference is expected to attract more than 800 tunneling and underground construction professionals. But don?t let the North American part of the meeting?s title fool you. Many of the attendees will come from all over the world. The meeting is scheduled for June 24-27 at the JW Marriott Indianapolis Hotel in Indianapolis, IN. In addition to two and a half days of technical programming, the accompanying exhibit has attracted 116 exhibitors in 140 booths. And the conference will include short courses, a field trip and plenty of social activities that will give attendees the opportunity to catch up with each other.

Jan 1, 2012

By Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa, Amilton Barbosa Botelho Junior

A new step in the Bayer process has been used to recover NaOH and to reduce its content in red mud. After digestion, the residue is separated from the Bayer liquor and goes through press filters, which enables the recovery of NaOH and decreases the moisture content. It is well known that red mud is one of the most important sources of scandium. For this reason, the goal of this work was to characterize a Brazilian red mud (BRM) for scandium recovery. The sample was collected after the press filter system process. Analysis of energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), and X-ray diffraction (XRD) was performed. Microwave digestion using an acid mixture was carried out to determine the concentration of the main elements. Fe2O3 represented 40% of the BRM, and the Sc concentration was 43 mg/kg. The SiO2 content was 24%, which is the highest value found in the literature, whereas the sodium concentration was the lowest. A literature review was carried out to compare results with BRM, as well as the current studies for recovery of scandium by the leaching/ion-exchange process. Scandium recovery using a leaching/ion exchange process may be possible with efficiency higher than 90%. The greatest challenge is the occurrence of silica gel formation during leaching.

Oct 19, 2020

By Michael F. Gleason

In 1986, Gold Fields began negotiations with a large Nevada electrical power utility to supply power for its Chimney Creek Mine In northern Nevada. After the long negotiations reached an impass over various costs associated with the power line, a decision was made by Gold Fields to generate its own power. Self-generation is not uncommon overseas, but it is rare for any but very large or very small operations in the United States. Surprisingly, under certain conditions a mine can generate its own power profitably and Gold Fields has found that the associated operating and maintenance problems are minimal. The following report details what factors went into this decision and how it works. Hopefully, it can serve as a guideline for those who may find themselves in a similar position.

Jan 1, 1990

By James J. Anthony

High-angle in-pit conveying is an idea that is being seriously studied by a number of important mining companies in North America. Its application in coal, iron ore, and copper mining is expected to reduce mine operating costs considerably compared with the conventional discontinuous methods, such as truck haulage, which are fuel, labor, and maintenance intensive. Therefore, a mine introducing high-angle in-pit conveyors will gain a competitive advantage over mines which continue to use conventional haulage. While the capital outlay for in-pit conveyor systems obviously varies depending on pit depth, the angle of incline, and the capacity required, it generally will not exceed that of truck haulage when all Factors are taken into consideration. These factors include the cost of excavation, as measured in relation to the volume of minerals mined, the cost of building truck ramps and roads, and the capital outlay for the trucks and maintenance facilities. In many cases, in Fact, the capital outlay will be less than for truck haulage. This cost advantage will best be realized by new mines, whereas in existing producing mines the switch from truck haulage may involve the abandonment of a substantial capital asset.

Jan 1, 1983

By J. A. Marts

Reservoir properties including porosity and permeability distributions in longwall coal mine gobs have direct application to modeling the flow patterns and gas distributions in the gobs. Proper assessment of these distributions is required to assess gob gas hazards such as spontaneous combustion and explosive methane mixtures and to optimize gob gas venthole operation and nitrogen inertization. Determining the reservoir properties is difficult given that the gob is inaccessible and direct measurements cannot be easily taken. Several techniques had been used by previous researchers and will be discussed. This paper will present the methodology used to model the gob compaction by simulating the sequential extraction of coal. Two Western US coal mines were used for case studies. By determining volumetric strain, the porosity and permeability distributions in the gob can be calculated. The geo-mechanical model predicts an axisymmetric volumetric strain distribution with a steeper slope near the start-up room and a shallower slope near the active face.

By M. E. Rossi, J. A. Bassan, J. B. Novillo

Sampling and geological models are the basis of recoverable resources models. They are pillars of mineral resources and reserves estimation, and what geostatistical methods for grade estimation should rely upon. The resource model is best estimated if geostatistical methods make good use of sound geologic models. Data collection from the original drill holes, including field procedures and the quality assurance and quality control (QA/QC) of those samples are pillar one of a resource model. The second pillar of the model is the good use of the logged geological information, resulting robust geological interpretations, and the corresponding three-dimensional models of those interpretations. These models are partly subjective and mostly conditioned by the quality of logging and the geologist’s experience. They are also conditioned by the quality of the three-dimensional models built, regardless of the modeling method employed, traditional or implicit. Grade estimation is more commonly done by applying some geostatistical method and using the two basic sources of information, data and geologic model. Multiple stages are involved in this process, and in all of them there are uncertainties and risks that have to be dealt with. Knowledge, understanding, interpretation, and management of the model’s fundamentals are critical, given that they directly affect its accuracy and predictive quality. The mitigation of related risks allows for the creation of opportunities, generating value and reducing the project’s uncertainty. This paper discusses some of the key variables, uncertainties, and risks involved in the resource modeling process, illustrating with specific examples; discusses possible risk mitigation alternatives, and proposes best practices to avoid or mitigate those uncertainties. Emphasis is placed on taking advantage of technological advances without ignoring fundamentals. INTRODUCTION In the area of mineral resource estimation, one alarming trend that these authors have observed in the past 20 years or so is that the care and diligence in checking the work as it progresses has generally diminished. This is, perhaps, an unintended consequence of the availability of new technologies and tools that attempt simplify and speed up the work involved. This has led to a more casual attitude towards checks and balances that have to be in place at any given stage of the process before proceeding to subsequent stages, as best practices dictate. To some extent, some of these aspects are covered in international standards for resource estimates reporting (JORC, 2012; CIM, 2010). But these are broad, and do not specifically recommend best practices to a level of detail that would have an impact on certain aspects of the process. There are numerous references in the geology and mining journals and conferences that discuss the consequences of poor recoverable resource models (Baker and Giacomo, 1998; Vaughan, 1997).

Jan 1, 2019

By Calvin R. Davis

The bucket elevator is probably the oldest known form of conveyor. Its history can be traced back to the days of Babylon where wicker baskets lined with a natural pitch and fastened to ropes operating over wooden sheaves turned by slaves, were used for the elevating of water into irrigation ditches. It is not unnatural for the bucket elevator to be the first in history, for even today engineers and designers recognize that well designed, correctly applied bucket elevators offer unequaled advantages over other bulk material elevating methods. The bucket elevator's vertical design saves valuable floor space. It provides flexibility of machinery layout with lowest initial capital expenditure, which is its principal advantage. While the advantages of the bucket elevator have long been recognized, there has been a tendency to lean away from its use because of high maintenance without reliability. CHAIN Belt Company found that the bucket elevator, if correctly applied, can be built to be as dependable and reliable as any other piece of machinery in today's modern processing plants. It is not difficult to understand why the bucket elevator is looked upon sometimes as a necessary evil in the material handling system. Very little has been published or written about the specific use or application of bucket elevators other than in manufacturers catalogs. Most of today's elevator application was set forth at the turn of the century by Hetzel (1). There have been many improvements made in the manufacturing techniques of elevator components, improvements in material selections, all which can be used to improve today's bucket elevator. To best understand the improvements which have taken place recently in the design and application of bucket elevators, an understanding of basic elevator principles is desirable. In general, it can be said that bucket elevators are classified into two basic types : (1) centrifugal discharge and (2) continuous. Elevators in use today are either of the centrifugal discharge type or the continuous type, or a combination of both in special applications.

Jan 1, 1958

By B. A. Wills

With the increasing need to mine lower grade ores, high energy-related costs in comminution are of major concern. Very fine grinding is needed to liberate the very fine mineral particles in these ores. Not only is this expensive but it leads to greater losses in 'slimes'. In the early 1970's, 50% of the tin mined in Bolivia, 30% of the phosphate mined in Florida and 20% of the world's tungsten were lost in this way (Somasundaran, 1979). Gravity concentration techniques become unacceptably inefficient for particle treatment below 25-50µm, and even flotation fails in the ultra-fine range. Two approaches can be adopted to try to overcome this problem. The first involves increasing the efficiency of existing equipment or developing new slimes treatment processes. Gravity devices such as the Bartles-Mozley concentrator have been developed for this purpose and good recovery has been reported from 100µm down to 5µm. Such machines, however, have relatively low throughputs, so that large areas of plant space are generally required. Flotation is rapidly growing in importance for the treatment of ultra-fine minerals traditionally treated by gravity concentration.

Jan 1, 1986

The 29th annual American Mining Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Star Pass Resort, Tucson, AZ on Saturday, Dec. 3, 2011. Each year, one living inductee, two recipients of Medals of Merit, and up to five honorees from mining history are chosen by the MFSW for their outstanding contributions to the mining industry. Chilean Minister of Public Works and former Minister of Mining, Laurence Golborne Riveros will be the guest of honor, featured speaker and inductee into the American Mining Hall of Fame. Golborne Riveros was instrumental in managing the rescue of the 33 Chilean miners in October 2010 and in the coordination/management of the ?townsite? for family members, rescue support and the media. His engineering background and executive management skills made him ideally suited to assist in both a technical and managerial role in this emergency.

Jan 1, 2011

By Donald W. Gentry

Introduction The mining industry is perhaps best characterized by the numerous and abnormally high risks associated with the business of mining and by its most basic assets - ore deposits, people and technology. At the most fundamental level, it is the quality and effective utilization of these basic assets that determine a mining company's ability to compete efficiently in the international market place. The gold industry has received much attention in recent years and especially in recent months, for good reason. This commodity serves as an excellent platform for the subsequent discussion of these three basic assets and their role in mining's future. Facets of the gold industry The fate of this noble metal in recent times illustrates some of the various risks associated with the mining industry and the importance of high-quality assets, whether they be ore deposits, people or technologies. The following comments pertaining to the gold industry help place proper focus on subsequent discussions. All monetary amounts given are in US dollars. Throughout 1997, falling gold prices broke record after record: first hitting three-year lows, then a 12-year low in July and finally an 18-year low at year's end. From Jan. 1 through Dec. 31, 1997, the price of gold fell by more than $2.57/g ($80/oz), or some 22%. The decline in gold-mining profitability and stock prices was even more dramatic. At the beginning of 1997, the 20 largest gold producers in North America had a market capitalization of approximately $44.5 billion. At year's end, this market cap had fallen to $26.2 billion, a reduction of 41%. The total market cap of all the world's gold companies fell from $71 billion to $46 billion, a 35% drop (Serwer, 1998). Analyses suggest that, at a spot gold price of $9.65/g ($300/oz), only one, or possibly two, North American gold-producing companies can make money when break-even or "total costs of production" are considered. While strong hedge positions mitigate this situation in the short term, clearly, this is an industry in desperate straits. For example, write-downs for North American producers in 1997 were approximately $2.5 billion. Speculative short positions in 1997 were near historical record highs and generally exceeded long positions by factors of 9:1 or 10:1. Much of this is driven by some US commercial banks, hedge fund managers and commodity speculators who can significantly move gold prices sharply over short periods of time by selling gold they do not own in the expectation they can buy it back at a lower price before they have to deliver. These signifcant short positions are likely to continue as long as central banks are willing to sell or loan gold to financial institutions that in turn make the gold available to speculators who hope to capitalize on price fluctuations. The Far East accounts for approximately 26% of the annual demand for gold. Including India, the region accounts for 43% of total demand. More than 85% of the physical demand for gold is for investment jewelry in Asia and the Middle East. This demand is extraordinarily price sensitive. The fairly recent turmoil in Asian markets and economies, combined with currency devaluations throughout the region, have made gold more expensive (30% to 50% in local currencies) for those peoples most likely to treat gold as a safe investment haven. Higher interest rates also have reduced the amount of money they have to spend on consumer goods such as jewelry. All of these recent Asian events are deflationary in nature. Deflation, if coincident with rising unemployment, could result in significant dishoarding of gold. There is one key fact to remember when analyzing

Jan 1, 1999

By William J. Miles

The markets and applications of Wyoming bentonite deposits are primarily determined by the functional properties of a bentonite ore which results from the unique mineralogy and chemistry of each deposit. Commercial bentonite products contain sodium montmorillonite as the major mineral component, with minor concentrations of accessory minerals such as quartz, opal (silica hydrate), mica, feldspar, gypsum and zeolites. The chemical composition of the sodium montmorillonite influences the functional properties of the bentonite in significant ways. The type and concentration of various accessory minerals also influence the acceptability of the bentonite in each market.

Jan 1, 1995

By L. R. McCullough

To compete in Today's Market, Mine Managers have two, often conflicting tasks. They are to improve productivity, allowing the mines to compete in our world markets and to improve the environment in which our miners must work. To Maintain and improve the environment to ever increasing acceptable levels requires monitoring. In years passed this required considerable labor, which was provided by the Ventilation Department. They continuously took manual samples using hand-held instruments, sampling gas level such as CO for fire and methane for explosive risks. In addition they took continuous air velocity readings with hand-held instruments which allow them to calculate the ventilation air movement in each area of the Mine. This manual gathering of information was not only expensive and slow but marginal at best. It was marginal because the gas sampling was sporadic rather than continuous, as sample reading taken in one part of the mine would likely not be repeated for another 8 hours. If problems did occur, they likely went unobserved until they reached crisis proportion.

Jan 1, 1990