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By Christopher M. St. John, Tony F. Zahrah

Empirical and numerical methods are the two extremes of the tools available for the seismic design of subsurface excavations and underground structures. Both have their limitations: when relying on purely empirical methods directly relevant experience may be scant; site data may be insufficient to justify a comprehensive dynamic analysis. The primary purpose of this paper is to review the analytical tools available to the design engineer of subsurface excavations and underground structures. Particular attention is devoted to simplifed models that appear to be applicable in many practical cases.

Jan 1, 1985

A study was undertaken to determine the effects of five industrial frothers on the relationship between entrainment recovery and water recovery. The experiments were conducted using a Batequip rectangular 60L steel flotation cell that was run in parallel with the first cell in a copper/silver prefloat rougher circuit. The concentration of the frothers ranged from 2.5 to 8.4 g/t. The experiments were repeated at three different froth depths. A power function was found to fit this relationship with no discontinuity in the relationship caused by the changes in frother type and concentration and froth depth.

Jan 1, 2002

By Sandy Clamage

"Seeing the elephant" was a term often heard from 1849 to 1859, the period of the great California Gold Rush. The phrase was used by those who dreamed of instant wealth that was believed could be found in California's virgin earth and mighty rivers. When news of fabulous gold strikes throughout the Mother Lode reached far away places, thousands of gold seekers left home and family to join in this incredible adventure. The barren, placid state of California soon became one of the most bustling, populous areas in the West. Before the Rush Before 1848, Mexico ruled California. It was then a remote region, isolated from the urbane world of the East by 2900 km (1800 miles) of scorching desert and impassible mountains. By sea, it was 29 000 km (18,000 miles) via Cape Horn. Spaniards and Mexicans settled the coastal lands on tracts donated to them by the Mexican government. The inland area was the domain of Indians and a few settlers who also had been granted estates by the government. Among those settlers was Captain John Sutter. He had been fortunate enough to obtain about 11 leagues of land (spanning 100 km or 60 miles in length) from Governor Alvarado of Mexico. Sutter was somewhat of a visionary and possessed a gifted tongue. He managed to receive most of what he desired with minimal trouble. Enchanted with Sutter's personality, Alvarado promised him Mexican citizenship. Alvarado also commissioned him to become "representative of the government and officer of justice on the Northern frontier." With uncanny foresight, Sutter began building a fortress on his land in the Sacramento Valley. It later became known as Sutter's Fort. It was more than just a fort, however. It also became a stopping place and home for many foreigners and Americans who traveled to California, and it eventually became the mecca for overland pilgrims. Sutter engaged in many projects. These included a cattle ranch, fur trade and trapping, and the construction of an irrigation system. With the influx of immigrants over the years, the community around the fort grew rapidly. Lumber was much in demand and Captain Sutter agreed to supply the necessary capital for a community sawmill. The site chosen was some 72 km (45 miles) northeast of the fort on the south fork of the American River in the town of Coloma. During the course of its construction, Sutter's carpenter, James Marshall, discovered a problem with the tailrace on the mill. First Strike Early in the morning on Jan. 24, 1848, Marshall was checking the tailrace. He noticed an object shining in a foot of water at the bottom of a ditch. He reached down and picked it up. His heart began to thump wildly as he realized he was holding a gold nugget. Sutter planned to keep the find a secret for as long as possible. He knew very well that he could become an extremely wealthy man. The ever loyal Marshall remained faithful to his employer and the pair did their best to obtain more

Jan 3, 1985

The 23rd annual American Mining Hall of Fame Awards Banquet sponsored by the Mining Foundation of the Southwest will be held at the Tucson Marriott University Park Hotel, Tucson, AZ on Saturday, Dec. 3, 2005. The Mining Foundation of the Southwest is a non-profit organization. It educates the public about the mineral industries and reports outstanding accomplishments in the fields of mining and the earth sciences. This year’s inductee, guest of honor and featured speaker at the banquet will be Pierre Lassonde, president of Newmont Mining and resident of the World Gold Council. He is one of Canada’s leading gold analysts.

Jan 1, 2005

By G. Barbery

A review is given of the present applications of random sets and integral geometry in fragmentation and liberation models of ores and minerals. Although attempts have ben made in the past to apply such mathematical techniques to the comminution of solids, it is shown that it would not result in major progress. In liberation modelling, it is demonstrated that the approach can lead to fruitful results. Following a recent paper by Davy (1984), a model of liberation prediction is developped, which can be calibrated far ore texture and breakage using image analyzers. The model is demonstrated for the case of a Poisson polyhedra ore texture and monodisperse fragment size. The model enables to predict the complete composite particle distribution, and is thus valuable for integration of ore breakage models with minerals separation models.

Jan 1, 1985

By N. Paas

Diesel powered equipment has been operated in underground coal fir mare than 50 years. According to the Mine Safety and Health Administration (MSHA), there are approximately 3,000 diesel units operating in underground coal mines in the United States. This number is expected to reach 5,000 diesel units in 250 coal mines by the year 2000. Also, there are approximately 5,000 diesel units operating in metal/nonmetal mines such as trine, potash and salt mines: and more than 3,000 diesel units operating in Canada. This increased popularity of diesel powered equipment over trolley wire, electric trailing cable or battery powered equipment is because of improved safety, greater mobility, higher productivity and increased power of diesel equipment. The operation if diesel powered equipment is not without challenges. Diesel engines generate exhaust emissions, in particular carbon monoxide, oxides of nitrogen, sulfur dioxide, unburned hydrocarbons, and diesel particulate matter that must be maintained at safe levels. The chief method to control ambient exposure has been dilution by ventilation. A new concept to ensure continued safe ambient emissions levels from diesel equipment in underground mines is the EMISSIONS MANAGEMENT PROGRAM™. The program encompasses all factors that will influence diesel emissions. By ESTABLISHING low tailpipe emissions through technology, such as clean engines, clean fuel selection, exhaust aftertreatment devices and filtration of the exhaust gases via the Dry System ™, this program ensures that the baseline emissions are at their lowest technically feasible concentrations. The DST Dry System™ exhaust conditioner reduces DPM by over 98%, as demonstrated through laboratory research at the West Virginia University. Carbon monoxide and hydrocarbon emissions and odor are similarly reduced. MAINTAINING these low emissions requires an expanded training program for operators and mechanics, onboard feed-back devices and a maintenance program with special focus on events and faults that can alter emissions. Finally, an on-board emissions sampling system allows the mechanic to VERIFY emissions levels and help diagnose engine faults. If the tailpipe emissions fall outside an established limit for a particular equipment, corrective actions will be initiated.

Feb 24, 1997

By Robert L. Zook

Coal refuse slurry impoundments are dams constructed of coarse coal refuse to impound fine refuse (slurry) and water (25-30% solids). Both products are waste from coal preparation plants. A number of these structures in West Virginia, Pennsylvania and Kentucky were investigated to determine embankment stability. During the investigation a variety of embankment designs were encountered. The investigation determined the soil and geological characteristics of the embankments and the sites. This was accomplished by a test drilling and monitor installation (observation wells and piezometers) program, geologic study, and large scale mapping which allowed sub-surface profiles of the embankments to be constructed. The laboratory testing program concentrated on textural classification of the coal refuse, permeability and determining strength parameters to be utilized in the stability analyses. For the stability analyses, the Modified Fellinius Slip Circle, Simplified Bishop Slip Circle and Analysis for Translational Failure -were utilized. In all stability analyses hydrostatic pressure and earthquake were considered. This investigation indicated that 62% of the embankments analyzed are in a stable condition. The coal seam mined, the type of roof rock, and the gradation of the refuse influence the degree of compaction obtainable and the permeability of refuse. The shear strength of coal refuse appears to be controlled by its composition, moisture content, degree of compaction, amount and grain size of fines present. This investigation demonstrated these em¬bankments should not be treated as pure state-of-the-art dams; consideration must be given to the particular properties of coal refuse and the total refuse disposal system. Refuse dim slurry impoundments generally lack the site se- lection phase that is standard practice with siting most other types of dams.

Jan 1, 1974

By Leslie Burnside

Homestake Mining Co. set out to complete final reclamation at a former open-pit gold mine in west central Nevada. The goal was to exceed regulatory standards by satisfying the company's own high corporate standards for successful reclamation. Homestake's completion requirements challenged available technology due to the unsuitability of heap material as a growth medium, the harsh environmental conditions of the site and the region's lack of native growth medium. Accomplishing these goals required enlisting a multidisciplinary project team to develop, test and implement appropriate and cost-effective revegetation alternatives.

Jan 1, 1999

By J. P. Hanten, G. Ramadorai

This paper presents laboratory and pilot plant data on the removal of heavy metals and molybdenum from mining-milling waste water. Molybdenum is removed as an Fe-Mo precipitate by proper addition of ferric sulfate. Heavy metals are lowered by lime treatment. Solid-liquid separation was achieved in both cases by flotation techniques. The Lectroclear electrocoagulation-electroflotation process was used to achieve the desired degree of metals removal. Good correlation was obtained on the laboratory and pilot plant scales. A two-step process consisting of the sequential removal of molybdenum and heavy metals was tested successfully using a mobile pilot plant. Preliminary data on sludge characteristics was obtained and the feasibility of recycling the iron sludge for iron and molybdenum recovery was established on the laboratory scale.

Jan 1, 1987

By A. J. Lynch

For over 30 years the JKMRC has been conducting research aimed at improving the understanding of comminution and classification processes. The result of this research has been the development of a range of comminution and classification models which has been successfully applied in numerous optimization and design studies throughout the Australian Minerals Processing Industry. This paper reviews the current status of our understanding of the mechanisms which govern comminution and classification processes. Outlines of mathematical models of these processes are described together with examples of their application in design and optimization studies.

Jan 1, 1992

By John C. Bowling

Many recent mine developments in North America are located in remote northern regions with extreme winter temperatures in the range of -20oF to -60°F. In addition, many locations are subject to very heavy snowfall. This paper discusses some of the key considerations in the planning and design of mine plant buildings, particularly concentrators, located in these regions. SUMMARY & CONCLUSIONS The subject is considered under three main headings: I. Building Out line and Structural Frame 2. Wall and Roof Materials 3. Foundations The plan outline of a mine plant building will naturally be governed by the scope and layout of the process equipment it contains. The selection of roof profile, on the other hand, will generally depend upon a number of factors extraneous to the process e.g. snow conditions. When these factors are considered for concentrators in cold locations, a flat or stepped roof will usually be more economical and suitable than a sloping roof. The materials normally used for the structural framework of concentrators are the same as used for other industrial buildings, namely steel, concrete and wood. Structural steel, however, is the most commonly used material for concentrators in

Jan 1, 1971

By J. F. Dresser

Managing environmental compliance at a complex facility has the potential to bring a high degree of personal and professional satisfaction to both the corporation and the individuals responsible for day-to-day operations. The decade of the 1990's, however, has seen the emergence of a nationwide trend of aggressive federal and state civil and criminal enforcement for environmental violations. This trend, spearheaded by the U.S. Department of Justice (DOJ) and the U.S. Environmental Protection Agency's (EPA) Office of Enforcement, has the potential to place the corporation, its corporate officers, and compliance personnel at collective professional risk, as well as a growing tendency to place accountability on individuals. Management of environmental compliance has been anecdotally compared to a shooting gallery at a carnival, with the following exception: At the shooting gallery, successfully hitting nine out of ten targets usually brings a reward and recognition of shooting skill; hitting nine out of ten environmental compliance expectations not only brings agency consternation and negative publicity, but the "gallery" will likely shoot back with stiff fines and possible criminal allegations. Faced with the challenges of the new environmental compliance shooting gallery, corporations and professionals are often left asking themselves, "How do we (or more appropriately, can we) win at this game?" This paper examines recent federal enforcement statistics and offers several suggestions for coping with the responsibility of managing environmental compliance in the 1990's.

Jan 1, 1992

By M. M. Rajkovich, L. Adams, J. J. Zaluski, S. Gardner

In 1998, Kentuckians for the Commonwealth filed an Administrative Petition with the Kentucky Natural Resources and Environmental Protection Cabinet to designate 8,903 +/- hectares (22,000 +/- acres) on Black Mountain, which contains the state’s highest point, as unsuitable for mining. A fast track legislative process was triggered which could have "taken"100 million tons of coal reserves or, in the alternative, imposed severe restrictions on mining. Even with all parties represented by reasonable individuals, this process can be extremely cumbersome and expensive. The legal and technical preparation for this unusual hearing process as well as issues and strategies of the negotiated resolution are reviewed.

Jan 1, 2000

By J. S. Ross

The significance and role of industrial minerals in Canada differ from those in the United States, The smaller Canadian industry has recently become well diversified and self-sufficient in most commodities, However, it depends on exports, principally to the United States, for much of its market, Imports are small, but imports of several basic products manufactured from industrial minerals are large. This nation is a leading world producer of asbestos, gypsum, sulphur, nepheline syenite, titania slag, potash and barite. It has reserves in asbestos for at least 30 years enough potash to supply the current world's needs for 2,000 years and sulphur reserves for 40 years of current world demand, One of the ilmenite deposits contains enough titania to supply the current world demand for at least, 25 years.

Jan 1, 1964

By T. Dombrowski

Acid-activated montmorillonite is used worldwide as a catalyst and as a sorbent for the enhancement and purification of petroleum products as well as vegetable and animal-based fats. The solid-acid character of the activated montmorillonite is imparted by the manufacturing process, giving it unique properties that are exploited in these industries. Several international companies and a multitude of local clay producers are focusing on improving the efficiency of their standard and specialized products. This paper will describe the use of acid-activated montmorillonite in traditional sorbent applications, as a solid acid catalyst, and other new uses.

Jan 1, 1997

By Z. Nivolianitou

This article aims at highlighting the importance of technological innovation, namely the potential use of Virtual Reality (VR) technology, as a Sustainable Development Indicator for the minerals industry. Nowadays, VR is regarded as a mature technology for real world representation, and it has been already applied in various domains such as architecture, topography, aeronautics, medicine, and lately in the process industry. Several industrial sectors already use VR tools, as the car industry for improving car ergonomics and design and the aviation industry for both pilot and maintenance crew training. It is well known that the mining industry, as well as the process industry, requires people to work in hazardous environments and situations, often inadequately trained owing to limitations in time and resources, building thus the potential for minor or major accidents.

Jan 1, 2007

By S. J. Jung

The prime criteria in the design of underground openings with complicated geological structures is ground control. Stability of underground openings for deep mines is critical because incorrect orientation or geometry of shaft, stope, and accessways often results in the failure of openings due to high stress conditions. Current design procedures for complicated orientation and geometry of mines are rapidly becoming inadequate as mines are being developed. In this study, finite element method has been used with optimization criteria to design more stable and safe underground openings.

Jan 1, 1993

By Paul Sarnoff

The economics of precious metals -- depending upon who is involved --could be the economics of hope, of fear, indeed of profit and perhaps survival. For those investors seeking capital gains in a puzzling economy, precious metals involve the economics of hope. Those who are convinced that currency soon won't be worth the paper it's printed on turn to precious metals because of the economics of fear. Gold and silver have been a storehouse of wealth since biblical times. The economics of fear during the past 500 years on the Continent has caused almost every European family to make sure a private stockpile or hoard of gold, silver or coins is at hand in case the paper currency of their country undergoes the kind of disaster that came to the German Mark after World War I. Understandably, for mining companies involved in the production of precious metals, the elements of operations and management are directly concerned with the economics of profit -- and perhaps survival. To the American miner the price of precious metals in the marketplace is a matter of daily concern. After decades of selling silver to the US Government at 64.64 cents an ounce, producing silver mines suddenly became faced with prices breaking $5, $10 and $20 per ounce, and approaching $50 an ounce during the period 1978-1981. What should the miner expect one year in the future? Five years?

Jan 1, 1981

By A. G. Oppegaard

Most iron ores treated by the R-N direct reduction process yield metallic iron products considerably lower in titanium, manganese, and chromium oxides and alkaline metal sulfates/sulfides than were contained in the original ores. These metallic iron products are suitable as feed stock for the open hearth and electric steel-making furnaces. The elements which are rejected in part are acceptable in the product since the product is designed to by-pass the blast furnace. R-N reduction conditions (PCO+H2-1 atmosphere, 1830° to 2150° F.) are adjusted for each ore. The iron ore which is reduced to 90 to 95 percent metallic iron is then subjected to the conventional beneficiation techniques. Under these conditions, 55 to 80 percent of titanium oxides, 75 to 95 percent of manganese oxides, 60 to 90 percent of chromium oxides and up to 97 percent of alkaline metal sulfates contained in the ore are rejected with the gangue to the non- magnetic tailings. The metallic iron products illustrated in this work contained 89 to 96 percent total iron, one to five percent TiO2, 0.2 to one percent MnO, 0.3 to 1.6 percent Cr2O3 and/or up to one percent alkaline metal sulfide. Usually only one of these components was present. Recoveries ranged from 80 to 96 percent of the iron in ore.

Jan 1, 1958

By E. M. R. Santos

Acid mine drainage (AMD) is a serious environmental problem in mining activities. Prediction is the first step for evaluate the potential of acid generation and there are some possible methods to estimate it. They are described as static tests, which examine the balance between acid producing and acid consuming materials, and kinetic tests, which attempt to predict drainage quality over time. Static methods are very simple and give a qualitative classification of the ores based on their potential to generate acid drainage. The characterization of ores to determine their acid producing potential is vital for the prevention of long term environmental liabilities. Laboratory tests were conducted under different methodologies to predict the acid producing potential of sulphide overburden, ore materials and tailings from a deposit of copper ore.

Jan 1, 1999