Search Documents

By Donald L. Bott

A computer model called the Quality Compliance Model was developed to optimize the mine planning and sequencing in area coal mining with respect to the limit on pounds of sulfur dioxide per million BTU imposed by regulations. The objective of the model is to maximize the amount of high sulfur coal mined from various benches while meeting the specified compl'ance standards. Given multiple seams and multiple benching operations, the mining sequence from each pit is simulated. The rate of mining is controlled such that the in-pit blending will maximize the usage of high sulfur coal and meet compliance standards. The compliant coal can be stockpiled for usage at a later date, or it can be disassociated. This calculation can be based on any given rate of production, i.e., from as small a unit as a unit train to as large as monthly or yearly production.

Jan 1, 1982

By Sahendra Ram, Ashok Kumar, Rakesh Kumar, AMIT KUMAR SINGH, Dheeraj Kumar, Arun Kumar Singh, Rajendra Singh

This paper describes the successful mechanized extraction of coal pillars in 11 panels using the fish-tail method from 2010 to 2017 at Pinoura Mine in India. This method proved its potential of coal recovery with efficient strata control under weak roof due to faster rate of extraction in a single lift. Observations of strata and snook behavior during the field studies in different panels of the mine are included.

Successful longwall gate entry design requires control of vertical and horizontal stresses. Vertical, or overburden, stresses are most severe in the tailgate where they are concentrated by longwall panel extraction. Horizontal stresses can also be highly destructive but they are less well understood. This paper discusses measurements of in situ horizontal stress fields in the eastern United States, experience with horizontal stress in longwall mines and methods for predicting and controlling horizontal stresses. The information presented was collected through site investigations at 45 US longwalls and an international literature review.

Jan 1, 1992

By Greg Beckstrom

Minnesota is a major mining state. This statement is not a dream or stretch goal but is a fact. As reported in a recent edition of Mining Engineering magazine, Minnesota ranks as the third largest state in terms revenues generated from nonfuels mineral production. The vibrancy of the mining sector in Minnesota can be attributed to several factors. The northeastern corner of the state is home to Minnesota?s iron range, one of North America?s largest deposits of iron ore. Iron ore from Minnesota is a strategic resource that has been [ ] instrumental to the nation?s development ? 90 percent of the iron used to build ships and planes during World War II came from Minnesota. Taconite pellets now produced from openpit mines on the iron range are shipped to steel mills worldwide. The growing appetite for steel in China and India has reignited once moribund mining operations throughout the iron range.

Jan 1, 2012

By D. Borrowman

Attrition of activated carbon in either the carbon-in-pulp (CIP) or carbon-in-leach (CIL) method of gold extraction can lead to, at the least, loss of expensive carbon that has to be made up, and at the worst, loss of both the carbon and any gold that was attached to it. Carbon attrition therefore represents a significant factor in both the efficiency and cost of the extraction process, and efforts to reduce attrition through process and equipment selection pay dividends. In evaluating carbon attrition potential, one would note that an individual carbon particle is in jeopardy virtually any time it is in motion. Since the motivators of this motion are primary centrifugal pumps, the purpose of this paper is to review the current styles of these pumps now in use and to examine their performance in minimizing carbon attrition.

Jan 1, 1992

By James P. Dorian, James M. Otto

The value of exported nonenergy minerals from the less-developed countries has increased substantially between 1970 and 1985, but their market share relative to world exports has remained stagnant. Of the top twenty minerals exporters, only four are developing countries. Production capacity in the developing countries is shown to be less sensitive to demand downturns than capacity in the developed countries. Two approaches to the management of cyclical minerals demand are given using examples from India and Papua New Guinea. The authors conclude that pro¬tective policies implemented by developing nations have, barring a few exceptions, relatively little impact on the chronic nonfuel minerals oversupply problem.

Jan 1, 1989

By Carl E. Nelson

Shallow epithermal stockworks hosted by maar eruption craters contain over ninety percent of the bulk mineable gold identified to date in the Circum-Caribbean region. Pueblo Viejo (Dominican Republic) and Santa Rosa (Panama) contain combined gold reserves of over 600 tonnes. Bulk mineable gold deposits are also being discovered in and around veins that were formerly mined underground. Bellavista, El Recio and San Martin (Costa Rica) contain combined announced gold reserves of over 50 tonnes. Representative rock suites collected at 8 bulk mineable gold deposits include 291 samples of veins and vein stockworks, hydrothermal eruption breccias, sinter, variably altered host, unaltered host, nearby intrusive rocks and basement. Analyses completed to date show that Circum-Caribbean epithermal ores are enriched in arsenic, mercury and antimony as well as gold and silver. Exploration efforts in the region naturally focus on districts with past production. However, an order of magnitude more bulk mineable gold has been discovered in shallow epithermal stockworks outside of the old bonanza vein camps. Exploration guides include basal island arc volcanic sequences, hydrothermal and hydrovolcanic (maar) eruption breccias, thinly-bedded carbonaceous maar sediments, and hot spring-related silicification and argillic alteration.

Jan 1, 1990

By Terry Ramsey, N. Finkelstein

INTRODUCTION The Cyprus Pima Mine is located 20 miles southwest of Tucson, Arizona and about fifty miles north of the Mexican border. The Cyprus Pima orebody was discovered in 1950. Feasibility studies were begun in 1952 employing underground development. Economic studies showed open pit operations to be feasible and stripping of overburden was begun in late 1955. The first ore was reached in October of 1956. A 3,000 tpd (tons per day) concentrator was completed and began operation January 1, 1957. From these beginnings, Cyprus Pima Mining Company has expanded into a plant processing approximately 54,000 to 56,000 tpd. Four expansions were required to bring the plant up to its present capacity. Each expansion incorporated what had been learned in previous operation of the plant. The first expansion was completed in August of 1963 doubling design capacity to 6,000 tpd. In reality, because of softer than average ore, capacity was closer to 8,000 tpd. Expansion I1 was completed in July 1966 bringing design capacity to 18,000 tpd. Expansion I11 followed immediately. Completed in the summer of 1967, this expansion increased the design capacity to 30,000 tpd. The actual dry tonnage of this portion of the operation in 1974 averaged 38,400 tpd, again, primarily as the result of treating softer than average ore. The latest expansion (Expansion IV), completed in December 1971 and utilizing a semi-autogenous grinding circuit, is located in a separate building (Mill 11) approximately 200 yards southeast of the original mill (Mill I). Expansion IV was designed for 14,000 tpd, but after circuit modifications, averaged 16,500 tpd in 1974.

Jan 1, 1976

By Geno Saccomanno

INTRODUCTION Cancer of the lung in uranium miners has been reported by many authors. In fact, it has become a most popular subject for comment by environmentalists, health physicists, and newspaper writers. I believe it appropriate for me to discuss cancer of the lung in uranium miners in a general way commenting briefly on etiology, incidence, tumor cell types, and particularly, tumor development and treatment. Cytological development of cancer in its incipient stages, particularly the in situ stage, relates to potential cure with photoradiation, early diagnosis, and treatment. Our observations of the cytological response to this modality of diagnosis and treatment will be discussed briefly since this area will also be covered by Doctor Balchum. The cause of lung cancer in uranium miners is primarily due to two carcinogens; cigarette smoking and radon daughter radiation. Cigarette smoking has continued at the same intensity over time among uranium miners; about 60% of the miners are cigarette smokers and 40% are non-smokers. Radon daughter exposure to the uranium miner has varied from mine to mine, but over the last 20 years has been reduced to a minor fraction (.3 WL) of the level that prevailed in many of the mines during the 1950-1960 era when many of the miners were exposed to more than 10 WLM. Sputum samples have been examined on as many uranium miners as responded on the Colorado Plateau since 1956. Autopsy studies were done whenever this was permissible. In some instances, only tissue from a biopsy of a node or lung was available for study. Smoking histories were also taken. Approximately 200,000 sputum samples were examined and histological examinations of lung lesions were made from 312 cases. METHODS The method of sputum cytological collection and preparation was reported previously. I The lungs were fixed with formalin and prepared for sectioning by Dr. Oscar Auerbach with his block-section method. RESULTS Three-hundred-twelve lung cancers from uranium miners were examined. The tumor types and the age at death for each type, smokers and non-smokers, are given in Table #1. The incidence of the tumors in the smokers and non-smokers is given in Table #2. The incidence of small cell carcinoma of the lung has decreased from an incidence of 76% of all the lung cancers found in uranium miners to 22% of these lesions (Figure #1). The decrease in incidence of this tumor is probably due to decreased exposure to radiation in the mines.

Jan 1, 1981

By Byron Belew, Juris R. Harlamovs, D. B. Dreisinger, John L. Watson, G. A. Kordosky, Thomas O. O’Keefe

Unwanted impurities, present in raw materials, are often coextracted along with desired constituents during leaching. Due to its abundance and ease of extraction, the presence of ferric iron in leach solutions, solvent extraction circuits, and subsequently in electrowinning circuits, has always been a problem. In the case of zinc hydrometallurgical processing, iron is frequently an impurity in leach solutions. Purification of such solutions by solvent extraction, using di (2-ethylhexyl) phosphoric acid (D2EHPA) in a kerosene diluent, results in ferric ions being readily extracted along with zinc into the organic phase. Ferric iron has proven difficult to strip from the organic phase, but it is known that ferrous iron may be easily stripped from D2EHPA, and hence a process to effect reduction of iron present in the organic would have great potential. This research investigated a process to directly reduce ferric to ferrous iron in the organic phase, and to strip the ferrous iron using a dilute acid solution. The process utilized metallic zinc as the reductant and a low concentration sulfuric acid stripping solution. The results of the laboratory tests illustrated that iron could be readily removed from the organic phase by simultaneous direct reduction and acid stripping. The reductive stripping process was subsequently utilized in industry at the laboratory and pilot plant levels. The results of the industrial tests were encouraging and demonstrated the potential of this novel concept.

Jan 1, 1993

By Jed Greenwood, Lyall Workman, Michael Haggerty, Russell Sheets

Draglines often work from a position on the active highwall or spoil side bench to remove undisturbed waste material and spoil in the previously mined pit. To protect the dragline crew members and the machine, it is necessary that the highwall remain stable while the dragline is present on the bench. In the past several years, we have been involved in determining the causes for highwall failures that included the dragline. While there have been no injuries and limited dragline damage with these incidents, the potential certainly exists for a more serious outcome. In all cases, the operation had completed a geotechnical study to support the ground control plan and pit designs. However, all these incidents included aspects that would not likely have been identified in studies to determine highwall and spoil designs to support ground control procedures. In general, these events included aspects that were localized and would have been difficult to identify in initial slope stability studies either observationally or during the soil testing and modelling efforts. Although the authors do not have quantitative evidence of this, it does seem there has been an increased number of events in recent years. This may be due to loss of institutional knowledge, mining in more challenging areas, or simply an increase in localized variation. This paper will describe some of the issues we have seen and what the causes of failure were. It becomes clear that avoiding similar incidents in the future requires on-going observation and inspection of active highwalls and spoil benches to try and identify local variability and impact on mining. The information can proactively be used to update stability modeling of any concerning issues to determine likelihood of problems and to develop solutions.

Feb 1, 2025

By D. R. Dixon

Since the critical role of oxygen in xanthate flotation of sulphides was established (1) subsequent studies have been concerned mainly with the galena-xanthate system. It is therefore surprising to find at the conclusion of a comprehensive review of the topic by Granville, Finkelstein and Allison (2) that it was not possible for them to draw unequivocable conclusions on the mechanism of xanthate adsorption. It was apparent that some new advances were likely if systems other than galena-xanthate (Pbs/x-) were examined. (2) Specifically a less reactive sulphide such as ZnS may interact with flotation reagents at a slower rate than PbS and more information per unit time gathered. Again ZnS is far less reactive electrochemically than PbS or stated equivalently, it is a poorer semiconductor than PbS. More importantly, the ability of ZnS to act as a semi-conductor can be controlled photochemically rather than by direct doping reactions for which it is difficult to assess the uniformity of doping. Thus the conductivity of ZnS can be made the same as that of PbS by irradiating the ZnS with ultraviolet light at circa 360 n.m. (3)

Jan 1, 1974

By Sergey G. Pushkin, Eugeny L. Schastlivtsev, Anatoly A. Bykov

Three years ago the authors and a group of assistants began to develop a GIs-system for integration of comprehensive eco- logical information to be linked to geographical maps of Kuzbass region. And now we have got the working system and some first results that the present paper deals with.

Jan 1, 1996

By Marco D. Boscardin

During subsidence, the ground surface may settle, change slope, change curvature, go into tension, and/or go into compression. In response to these ground movements, buildings and buried utilities in the subsidence area may settle, tilt, bend, distort, and sustain extension, compression and/or torsion. In order to develop measures to protect existing structures and utilities, or to design new structures and utilities to withstand potential movements in areas of subsidence, it is necessary to understand the interaction between the ground and the building or buried the utility. This paper reviews subsidence-induced ground movements, how these ground movements are transmitted to and accommodated by buildings and buried pipelines, and how these structures may alter ground movements relative to free field subsidence-induced ground movements.

Jan 1, 1986

By Terry Ritzel

Predictive maintenance technologies include vibration analysis, tribology, infrared thermography, ultrasonic detection and electrical measurements. These technologies have been applied to large electric mining shovels at the Cyprus Sierrita Mine outside of Tucson, AZ. The predictive maintenance program was initiated on the P&H models 2300 and 4100 electric shovels during August 1996. Results of these technologies have shown the potential for improving electric min- ing shovel availability and minimizing maintenance costs. Predictive technologies provide the tools to assess machinery condition. Availability is enhanced by the condition-based planning of component replacement. Maintenance costs are minimized by focusing resources through condition-based prioritization.

Jan 1, 1997

By Robert F. Conley

In the mining, manufacturing and application of inorganic pigments, dispersion contributes significantly. This is especially true with mineral pigments because of the variety, in slurry operations required for their processing. Such operations include any of the following: (1) mine-transport (2) wet grinding (3) flotation/beneficiation (4) wet magnetic separation (5) selective floculation (6) size classification (7) chemical processing (8) spray drying Dosage levels and general economics of dispersant use are broadly variant, being dependant upon the agents employed, from the simplist, i.e., sodium silicate or sodium carbonate, to the more complex, as polyacrylates and organo-phosphates. In certain unit processes the dispersant must exhibit unusual chemical stability and persistence, e.g., in protracted pigment slurry shipments. In others, the agent should be fugitive to prevent secondary reactions from occurring, e.g., with high temperature calcination where alkali salts can act as aggregation fluxing agents.

Jan 1, 1985

By Yadong Xue, Fei Wang, Hongwei Huang, Yan Sun

"Increasing attention to subway tunnel maintenance is being paid with the high speed development of urban rail transit system in China. A novel moving tunnel inspection equipment based on machine vision is developed in this paper. High resolution image acquisition system is proposed for tunnel crack and leakage inspection. The main components of this image acquisition system includes high speed CCD cameras, linear lights and high performance computer. To inspect the crack less than 0.3mm with a 3-5km/h speed in subway tunnel, we need to consider resolution and line rate of camera, pixels of cameras, range of inspection and illumination intensity of lights simultaneously. The optimization design is proposed to make the equipment more convenient for tunnel use. Entire tunnel situation can be detected and recorded in a single inspection process. This equipment has already been verified in Shanghai subway tunnel for defects inspection.1. INTRODUCTION In China, the quantity of subway tunnel has reached a large scale in recent years. Until 2014, there had been more than 2300km of subway tunnel in China which accounted for nearly three quarters of Chinese urban railway system (Zhang Chen,2015). In some metropolises like Beijing and Shanghai, most of the metro tunnels has already run over 20 years which within maintenance phase. This has brought about plenty of inspection work and maintenance work to guarantee the tunnel under the serviceability limit states. The increase of running mileage of subway tunnels in China has been displayed in Fig 1."

Jan 1, 2016

By D. J. Sweet, B. Seymour, T. M. Emery, M. Armatys, J. P. Bourgeois, W. Johnson

The Spokane Mining Research Division (SMRD) of the National Institute for Occupational Safety and Health (NIOSH) has partnered with a narrow vein, hard rock underground mine to research the effects of the binder content on the elasticity and post-peak ductility of cemented hydraulic backfill (CHB). This is part of a larger study to enhance the long-term integrity of ground support in underground mines. As mining advances deeper and stresses increase, CHB mix designs will benefit if they can be modified to handle higher levels of strain which are induced by an increased stope closure, typically affected by a reduction in stope width and increased mining depth, or through dynamic loading resulting from a local seismic event. This portion of the research examined the impact of reductions in binder and their impact on Young’s modulus, peak strength, and post-peak ductility.

Mar 2, 2022

By John O. Marsden

Technology development has played a crucial role in the minerals industry throughout history. The development of new technology allows mankind to produce metals and minerals at progressively lower cost of production in real terms, and therefore at progressively lower prices, improving their availability, accessibility and utilization worldwide. However, the developers of such technology are not guaranteed to reap the benefits from this effort: There is an expectation that technology developers will gain an advantage over their competitors. Is this a short-term benefit that results from a temporary cost or efficiency improvement, or is it a sustainable longer term "edge" that prevails even after metal or mineral price has been eroded by the implementation of a major step change technology? This issue is examined by reference to several case study examples in the copper industry. BACKGROUND The development and adoption of new technology has played a crucial role in the commodity minerals industry throughout history. As new, cost-efficient technologies are commercialized, the cost of production decreases, and this enables lower grade ore to be processed profitably. This in turn increases the availability and supply of the metal or mineral of interest, and ultimately (in a free market environment where the supply- demand balance determines price) inevitably decreases the metal or mineral price. This leads to the question: Why should mining companies invest in (new) technology development if the result is a decrease in the product price? The answer is to achieve competitive advantage, where the application of new technology enables one or more

Jan 1, 2004

By F. Sime, X. Wang, J. D. Miller, T. Akinseye, S. Assemi, L. Pan

Respirable coal mine dust (RCMD) is a complex mixture of carbonaceous and mineral particles with a variation in size and shape. Accumulation of RCMD in the lungs of underground coal miners results in severe respiratory damage and ultimately progressive pneumoconiosis known as the black lung disease. The occurrence of the black lung disease dropped to a low of 2.1% in 1990s but has increased to 3.1% in 2000s [1], prompting more research on coal mine dust mitigation. In addition to surveying the impact of new mining technologies on the size of generated dust and exposure measurement, a comprehensive characterization of physico-chemical properties of RCMD particles are essential for a better understanding of the adverse health effects of coal mine dust. Such vital factors include particle size, surface charge, morphology, composition, and agglomeration state. The respirable fraction of RCMD, has been designated as particles < 10 μm in diameter, and almost all studies on the RCMD toxicity have focused on micron-sized particles. However, recent toxicological studies have shown that nanoparticles (particles with one dimension less than 100 nm) can have a magnified toxicity compared to the larger particles with the same chemistry [2]. Nanoparticles have a much higher specific surface area compared to the same mass of larger particles and are thus more reactive. Most micron-size particles can be cleared by the body’s defense mechanism. However, inhaled nanoparticles can easily deposit in all regions of the respiratory tract and can translocate to vital organs. [2].

Mar 2, 2022