Search Documents

By Jerry Dolph

In September 1855, 55-year-old Noah Spencer Kellogg and his $3 jackass named Bill discovered what was known at the time as a “blow out” of high-grade lead and silver ore. The deposit was located on the side of a North Idaho mountain high above the South Fork of the Coeur d’Alene River. The ore was later assayed at 41,141 g/t (1,200 oz/st) silver. Kellogg named his discovery the Bunker Hill Lode, after the June 17, 1775 Revolutionary War battle of Bunker Hill. A thriving pioneer settlement sprang into existence around the resulting mine’s workings and was eventually— and appropriately — named Kellogg. The peak rising hundreds of feet above the mine’s adit was named “Jack-ass Peak” after Noah Kellogg’s hairy companion.

Jan 1, 1996

By Thomas F. Joyce

N L Industries, Inc., MacIntyre Development produces ilmenite and magnetite concentrates from its own open pit operation at Tahawus in New York's Adirondack Mountain region. The ilmenite concentrate is used within the company for the production of titanium dioxide pigments and the magnetite concentrate is sold to heavy media processors. Current production is from South Extension mine, loading by by six-yard Marion electric shovels into 85 ton Lectra Haul trucks. Bench heights are 44' and are drilled with a Robbins Rotary 9 7/8" diameter hole on 25' spacing for a yearly production of 3.4 million total tons of rock. The ore deposit occurs in veins dipping on the average at 40 degrees to the west. The ore body, which is divided into three zones, outcrops at surface and continues to depths of 800'. Zone 1 is a high grade band of thickness 150-200' with an Fe/Tio2 ratio of 2. Below this band is Zone 2, a low grade band of thickness 50-100' with an Fe/Tio2 ratio of 2 and beneath that seperated by a band of anorthosite is Zone 3, a high grade band of irregular thickness 50-450' with an Fe/Tio2 ratio of 1.6.

Jan 1, 1973

By T. P. Meloy

Improvement of grade and recovery requires the use of optimum processing circuits. Critical to an optimum circuit is the set point for separation. With the introduction of the concept of circuit analysis (Meloy, 1982), it became possible to determine optimum circuits for a given task. No analysis, however, has yet been made as to the grade requirements of the larger circuits. Williams and Meloy (1982), reviewed the literature and concluded that, within the operating range, most unit operations involved in particle separation behave linearly. For the purposes of this analysis, linearity will be assumed. Grade, G, is defined as the weight of the coal mineral, C, that appears in the product, divided by the weight of the coal mineral plus the weight of the gangue mineral or waste mineral, Q, which appear in the product.

Jan 1, 1982

By Luis Yacher

CONTAC Engineers is a Chilean based company which works on process control and automation, principally for the minning industry. Jointly with other local and international engineering firms, CONTAC has participated in most of the last expansion and modernization plans being carried out at the Chilean pinning industry. At presente, CONTAC is involved on a research and development plan for the design and implementation of new instrument and process control procedures for mineral process automation. One of these efforts is the design of an ore size analyzer for coarse ore being transported over a conveyor belt. A feasibility and prototype study was made at a SAG Mill Plant and currently a high resolution, high speed analyzer is being developed. It will became available on early 1986.

Jan 1, 1986

By John H. Paugh

Hydraulic slurrying and pumpability characteristics of phosphate matrix (ore) have not been quantitatively defined. An elemental triangular diagram analysis of rock/sediment texture is used to classify the nature of the ore; then related to empirical field data of hydraulic pressureand production yardage ratios. This experiment is applied as a geotechnical tool to provide empirical data of ore slurry and pumpability characteristics as key considerations in the design of slurry pipeline systems. A real texture variability maps are developed on a section of land to assist mine engineering planning.

Jan 1, 1981

By Terrence J. Stobbe

On the job injuries to the musculoskeletal system are probably the oldest of the industrial safety problems. Long before we had pinchpoints to guard, chemical vapors to ventilate, and noise to enclose, people were getting strains, sprains, and sore backs from their work activities. In spite of the age of the problem, it remains a long way from being solved. The past ten years have seen a significant commitment by the sci¬entific community to understanding the problem. Engineers, scientists, doctors, and epidemi¬ologists have been involved, and as a result, today we have a much better understanding of the problem. The first step in understanding a problem such as this is to explore its history and epidemiology. The research done by Chaffin (1977), Snook (1970), Ayoub (1978), the ILO (1962), and others, led NIOSH to publish its Work Practices Guide for Manual Lifting in 1981. The guide was based on research carried out in general industry, but subsequent research by Stobbe (1983) and Peters (1983) has suggested that the nature of the problems producing injuries in underground mining is the same as in general industry. The problems are more intense in the mining environment.

Jan 1, 1984

By Claus Becker

The new, 2.600 m long pipe under the river Elbe in Hamburg/Germany required for 2 traffic lanes, emergency lane and space for utilities a boring diameter of 14,20 m(46,6 ft). According the geology (glacial deposits consisting of clay, sand and marl, all containing big boulders) a Slurry-Shield with crusher was selected. With a minimum cover of 7 m and a maximum pressure of 5,6 bar extensive ground treatment was necessary to make the drive feasible. The machine contains a lot of new developments. The drive was finished in spring 2000 so all experiences can be reported. A special risk sharing contract avoided completely litigation.

Jan 1, 2001

By D. W. Tuckwiller

Electroplating is a widely utilized but little understood process. The fact that the average person is in contact with dozens of plated items daily without even being aware that they are electroplated is evidence of the success of the process. Although a complete explanation of electrodeposition involves thermodynamics and modern theories of bonding and catalytic reactions, in its simplest form the process conforms to the following description. A metal salt dissolved in water partially dissociates into negatively charged and positively charged ions. In the case of nickel sulfate dissolved in water, for example, a portion of the salt dissociates into positively charged nickel ions and negatively charged sulfate ions. If an electrical potential is applied between two electrodes in this solution, the nickel ions migrate toward the cathode and the sulfate ions toward the anode. The negatively charged cathode has a high concentration of electrons, which combine with the positively charged metal ions to form neutral metal atoms with a stable electron configuration. These insoluble atoms thus form a deposit on the cathode.

Jan 1, 1970

By M. J. Laurila

Simulation of coal preparation circuits is becoming a widely practiced technique used for the design of coal preparation plants. On a much more limited basis, simulators are finding application in off-line process control. A typical application in the latter category involves inputting projected coal washability data for a shift into the simulator and using the software to optimize product quality and recovery within a range of predefined specifications. The plant is then operated at SG?s of separation determined from the simulation exercise for the one shift time period. This procedure is useful in that it incorporates some form of advanced planning into preparation plant operations. There is an attempt made to reflect changes in feed coal quality on a shift by shift basis rather than continually running the plant near design specifications with changes in SG?s of separation being made in response to an inadequate sampling program which only provides a spot measurement of material that has already passed through the plant. Instead of instituting changes on a shift by shift basis, NHI has proposed a method whereby monitoring three major operating parameters, * Feedrate to jig * Flowrate from hydrocyclone overflow * Density from cyclone overflow the ongoing plant operating performance can be accurately predicted on a continual basis, i.e., updated hourly. Using a distribution curve to predict the split between the clean coal and refuse from a given separator does not account for variations in efficiency that occur as a result of variations in operating parameters. NHI and Arch have studied the effect of both jig loading and solids content in the recirculating load to the jig on product quality. As a result, relatively simple measurements can be made on-line in a preparation plant which will provide input data to the simulation program that enables the prediction of jig/hydrocyclone circuit performance on a real time basis.

Jan 1, 1985

By A. Kosiór

Many remnants of gold exploitation in the Middle Ages were found in the Lower Silesia region. The oldest evidence of such activity was found in the neighborhood of Zloty Stok and comes from the 7th century. Mining of precious and non-precious metal ores has a great relevance in the late Middle Ages when advanced metallurgic technologies were mastered, that allowed to obtain gold, silver, lead, copper, zinc and arsenic from complex ores occurring in the oldest middle part of Sudetes. Historically it concerned the area of the Swidnica Principality and Klodzko County. Experience obtained in Freiberg, which is located close to the Lower Silesia, was used in the development of mining. A high level of mining and metallurgic technology was obtained in the 15th century that caused significant increase of production of the metals mentioned above. Unfortunately, the good time of Lower Silesian mining lasted only up to the 18th century; the notion of preservation of cultural heritage was unknown at that time. The Lower Silesian medieval mines were not in such a fortunate situation as the ?Wieliczka? and ?Bochnia? mines, which are operating to present-day, and which made preservation of the most interesting headings and objects possible. All these objects are now available for visitors. However, in the case of the middle Sudetes it seems that it is often sufficient to localize old shafts and headings on the basis of careful observations and old maps and carry out some earthwork to uncover medieval headings and objects of underground mining activity. They are often preserved in amazingly good state; this also pertains to mining devices. Another issue is of course the permanent preservation of that heritage and its possible availability for re-searchers and tourists. Some success has been achieved in that field (Zloty Stok Gold Mine is a good example), but also problems were encountered in many cases. The Lower Silesian Coal Basin, which has not been exploited for 10 years is an evidence that there is not a holistic conception of mining heritage renovation. Many attractive mining objects disappeared irrecoverably from the mountainous landscape of the Middle Sudetes despite common consciousness of their significance for cultural development of Silesia and other regions.

Jan 1, 2006

By Robert E. Moore

Investigators have attempted to develop lime refractories on a scale for broad applications in the metal and ceramic industries for several decades. There was a flurry of activity in the early to mid-fifties but no commercial developments were forthcoming. The literature of that period yields little information on plant trials. A major factor suppressing past interest in lime has to have been the high success with the application of magnesic and dolomitic materials. These materials, usually tar-bonded or impregnated, have become the refractories success story of the past two decades, especially in BOF applications. It is safe to say that their development and application has essentially plateaued, and that work today is focussed on finding cheaper paths to produce MgO-based refractories. For example there are efforts underway to extract MgO from mineral magnesite and to combine natural dolomite with MgO1. Beginning in the late sixties, rather intensive research began on the development of CaO brick, especially in East and West Germany, in Poland, and other communist bloc satellites, 'and also in Italy and Spain. One speculates that the motivation was a regional shortage of good magnesia and dolomitic material. Of course, There has always existed the prospect of cost savings should it be possible to use raw limestone as the starting material. Quite a large literature has appeared treating of these developments which in the early seventies had already reached full plant scale trials and uses. Some of the directions followed in the research have led to novel methods of brick manufacture.

Jan 1, 1985

The National Mining Hall of Fame and Museum will hold its Ninth Annual Induction Banquet Sept. 8, 1996, at the Las Vegas Hilton Hotel. Six mining greats, two of them living, will be enshrined at the event. They will join 126 other mining legends previously honored by the hall of fame. The keynote speaker will be William Perry Pendley, president and chief legal officer of Mountain States Legal Foundation in Denver, CO. Jeffrey Zelms, president and chief executive officer of The Doe Run Co., will be master of ceremonies. Richard Swayne, regional director USA for Boart Longyear Co. of Salt Lake City, UT, will introduce the speakers. Thomas Falkie, president of Berwind Natural Resources Corp. and chairman of the Mining Hall of Fame’s board of governors, will enshrine the inductees.

Jan 1, 1996

By Keiichi Fujita, Michio Miyoshi, Hisashi Miyazaki

In the construction of "Hamacho" subway station (Tokyo Metropolitan Rapid Transit), in order to minimize ground surface settlement, the pipe-roof method was employed as an auxiliary measure when removing the portion between two parallel shield tunnels to form one large tunnel for the station. 14 steel pipes (dia.1,219.2mm, length 75m) were driven in horizontally so as to cover tunnels and support heavy and extremely soft covering soil and surface structures. Procedures of temporary supporting, excavation under compressed air, reinforcing, concreting, etc., and some comparisons with conventional methods are described.

Jan 1, 1979

By M. E. Orman

Many factors must be considered when designing a heap leach pad. Geotechnical properties of the ore, can and will affect how well an ore leaches, the solution recovery, stability of the heap, and settlement. As a heap is stacked some of these properties will change due to the increased load. In order to properly design a heap these properties should be determined beforehand so that the heap performs as intended.

Jan 1, 1997

By A. D. Randolph

Comminution represents one of the major costs of mineral recovery from low-grade ores. Efficient mineral recovery in a typical low-grade ore grinding-flo¬tation process depends on grinding the ore small enough to liberate mineralization without producing excessive slimes, which would result in higher power and flotation reagent costs. Size criteria for efficient grinding should be stated in terms of the distribution of mineralization sizes, but as the mineralization-size distribution is difficult to determine, less desirable criteria of absolute particle-size distribution (PSD) are used in practice. Thus, there is considerable incentive to be able to analyze and predict the PSD performance of grinding circuits for control and optimization of the process. Any realistic model of a grinding circuit must account for recycle of oversize material; such oversize recycle adds to the total mill load and limits total production rate. Simulation of such closed-circuit operation to study grind factors affecting total throughput can be done in a straightforward fashion provided recycle calculations can be added to an accurate input-output model of PSD in the grinding mill itself. Such a total simulation of mill performance is of obvious practical value in assessing the practicality and benefits of various over-all mill control schemes and/or modes of operation. For example, considerable interest has been shown in the development of continuous on-line particle-size sensors and such instruments should be an operating reality in a few years. A total closed-circuit PSD model of this type would be invaluable in the utilization of, and in predicting the pay-out from, such an on-line particle-size sensor. The purpose of this paper is to present a new approach to the development of an input-output PSD model of a grinding mill. The model is continuous in the par¬ticle size coordinate, L, and is based on the principle of a particle population balance along the particle size coordinate. Most previous studies of the grinding unit operation attempt to relate power

Jan 1, 1971

By Jianmin Qin, Raja V. Ramani

In this paper, the results of a research study on airborne dust transport in a full scale simulated longwall face are presented. The simulated longwall face was set up in the Lake Lynn Laboratory mine of the U.S. Bureau of Mines to conduct experiments under controlled conditions. The controlled parameters in the experiments were the dust dispersion rate, dust size distribution, density of the dust, air velocity, and the rate of travel of the dust generating source. The analyses of the experimental results on mass concentrations, particle size distributions, and real-time respirable dust concentrations are discussed. There are definite spatio-temporal trends between the location of the shearer, the concentration at any location in the face, and the dust generation rates. The size-consist and density characteristics of the source dust, the air velocity in the face, and the air leakage into the gobs all affect the concentration.

Jan 1, 1995

By W. G. Cornwall

The mining field, inclusive of the treatment plant is located in the foothills, five miles inland from the northern coast of Viti Levu, the largest and most important island of the Fiji Group. Gold and silver occur as tellurides, associated with the sulphides, and as minor occurrences of electrum.

Jan 1, 1975

By John M. Smith

Kaolin is an important industrial mineral because of its unique properties and low cost. Strictly defined, kaolin is the name given to a group of hydrous aluminum silicates of which kaolinite is the most common mineral (1). Through common usage the mineral, kaolinite, is called "kaolin" or "china clay". In 1972 over 4, 000, 000 tons of kaolin will be beneficiated and shipped by domestic producers. By far the largest user of kaolin is the paper industry which utilizes approximately 65 to 70 per cent of the total production. Kaolin is used in paper as a filler in the interstices of the sheet and as a coating to impart smoothness, gloss, brightness, and printability to the paper. The rubber industry is also a large user of kaolin where it is used as a filler because it adds strength, abrasion resistance, and rigidity to both natural and synthetic rubber goods. Kaolin is used as an extender in paints because it is chemically inert, has a high covering power, gives desirable flow properties, and is low in cost. In ceramics, kaolin is used in whitewares, tile, insulators, refractories, and in some face brick where a white color is desired. Kaolin is also used extensively in plastics as a filler in thermosetting and thermoplastic mixes to give smoother surfaces, a more attractive finish, good dimensional stability, and resistance to chemical attack. Many other process industries use kaolin as a filler, suspending medium, or for color improvement.

Jan 1, 1972

By Peter Hall

The need for large volume covered storage has increased drastically in the last ten years. Increased world demand for such products as thermal coal, potash, metallic concentrates, etc., availability of land for large open storage and environmental issues have brought about this need. This paper discusses briefly demand, environment, types of covered storage and the Alternative Storage System "Eurosilo", a proven system for storage of dry bulk mateials in units up to 100,000 m3.

Jan 1, 1982

By G. T. Adel

During the past decade, researchers at Virginia Polytechnic Institute and State University have worked to develop a novel flotation process for treating very fine particles. This process, which is now commonly known as [microbubble column flotation] (MCF), has been shown to be very effective in a number of applications related to fine coal processing. These applications include the retrofit of existing preparation plant circuits and the recovery of additional coal fines from refuse streams. In addition, work conducted under the sponsorship of the United States Department of Energy indicates that the MCF process is capable of producing superclean and ultraclean coals from many eastern U.S. coals. This paper describes some of the basic problems associated with fine particle flotation and the design and operational features of the MCF process used to minimize these problems. Also presented are the results of ongoing pilot- and field-testing programs.

Jan 1, 1989