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By D?Arcy R. George

A survey of the copper mining industry in Western United States revealed that uranium is almost universally present in the solutions resulting from leaching the waste ore dumps to recover copper. The U308 content ranges from about 2 to 15 ppm and a potential production of up to 1,000 tons of U3O8 per year is indicated. A six-week pilot plant test at the Bingham Canyon mine of Kennecott Copper Corporation showed that the uranium is readily recoverable by ion exchange techniques. The design of the new types of countercurrent ion exchange columns and operation of the pilot plant are described.

Jan 1, 1967

By Francisco J. Escandon V.

Numerous lead-zinc-barite-fluorite ore deposits, with simple mineralogy and roughly concordant with bedding, are found widely distributed all over the world, having been denominated and well described as "stratiform deposits" or "strata-bound ore bodies", not having any genetic relationship. During several years, its origin has been discussed, without getting to general agreement regarding the main mining districts of this type. Through studies made of large stratiform deposits in the United States, Europe and Russia, it has been found that there are, within this classification, syngenctic diagenetic and epigenetic ore bodies. During the Symposium about the genesis of the stratiform lead-zinc-fluorite-barite deposits, carried out in New York in 1966, Frank G. Snyder (1), presented an excellent analysis of the theories of the origin of these deposits and of the evaluation of the criteria regarding classification. As per his definitions (Table 1), "a deposit is syngenetic if formed by processes similar to and simultaneously with the enclosing rock, epigenetic if introduced into a pre-existing rock and a diagenetic origin implies deposition of metals with the host sediments but with recrystallization, rearrengement and limited migration".

Jan 1, 1974

By John S. Owens

The National Steel Pellet Project and the Butler Taconite Project are operated by The Hanna Mining Company in the vicinity of the towns of Keewatin and Nashwauk, on the western Mesabi Range. Production began in 1967, after seven years of exploratory and development diamond drilling and reconnaissance magnetic surveys, Previously, direct shipping hematitegoethite ores and gravity concentrates had been produced in the area from numerous open pits and several underground mines since the start of the century. Total shipments of these oxidized ores amounted to more than 200 million tons, but at the present time such reserves are nearly exhausted, and there are no mining operations in the Keewatin-Nashwauk area except at the two taconite projects. The locations of all of the present taconite operations on the Mesabi Range are shown in Figure 1, extending for a distance of about seventy miles from the Butler plant to the Dunka River area. The Butler and National plants have a combined rated capacity of 4.4 million tons of pellets. Their reserves cover a combined strike length of about eight miles on the Biwabik iron formation. All of the intervals between present taconite operations on the Mesabi are potential sources of additional magnetic taconite; in particular, exploration and economic studies have been carried out by Jones and Laughlin Steel Corporation in the Biwabik area between Aurora and Virginia, and by Pickands Mather and Company in the Hibbing area. However, west of the Henna and Butler holdings, it appears unlikely that magnetic taconite exists in commerical quantities at economic depths due to extensive oxidation of magnetite to hematite.

Jan 1, 1968

By William E. Horst

Ore grindability data based on various techniques to measure comminution characteristics are used to evaluate the crushing and grinding efficiency in mineral processing operations. The importance of achieving improved comminution efficiency, in terms of energy consumption, has been emphasized by recent increases in the cost of electricity. From a theoretical standpoint, the objective of a grinding operation might be expressed as maximizing the production rate at a given grind size while minimizing the energy consumption per ton of material ground. To achieve this objective in an industrial operation presents a challenge especially in view of changes in the raw material which are normally encountered. Various procedures1-5 used to determine energy-size parameters and grindability measurements have been reported. The proposed relationships between particle size and energy consumed have much in common between many of the techniques for measuring grindability. Probably the most widely used parameter to measure ore grindability in recent years is the Bond work index6, Wi, which is defined as the kw-hr per ton required to break from infinite size to a product size of 80 percent passing 100 microns. If the breakage characteristics of a material remain constant over all size ranges, then the calculated work index would be expected to remain-constant since it expresses the resistance of material to breakage. However for most naturally occurring raw materials differences exist in the breakage characteristics depending on particle size, which can result in variations in the work index depending on grind size. Consequently work index values are generally obtained for some specified grind size which typifies the comminution operation being designed or evaluated.

Jan 1, 1975

By R. H. Lambeth

Disposal of mine tailings in "waters of the United States" is presently prohibited even though case studies indicate that the practice may be environmentally viable. To simulate disposal in the natural environment, nine containers of tailings and sediment were instrumented and placed on the ocean floor near Juneau, AK as were ninety-six biosample containers. Pore water concentrations of five metals were determined, and biota populations were characterized for both materials. After 500 days of exposure there were no statistical macro scale differences between tailings and sediment biota populations or Cu, Pb, and Zn pore water concentrations. Tailings released slightly more Fe than sediment, but sediment released significantly more Mn than tailings. Disposal of mine tailings in marine waters may be environmentally safe.

Jan 1, 1998

By Manuel Bernales, Aldo Leon, Alexandra Carlier, Bern Klein, Andre Xavier

Mining companies and governments at both the local and national levels recognize that Participatory Environmental Monitoring and Surveillance Committees (PEMSC) are necessary mechanisms for meaningful engagement at the community level. In many cases, PEMSCs are established as volunteer initiatives by mining companies or by the mining communities themselves. In Peru however, they can also be recommended by the government as way to address social conflict. Most PEMSCs are launched while a mine is in operation and have the objective of monitoring both water quality and quantity. Many established committees are currently evolving and adopting a more comprehensive approach, as well as expanding their initial scope from a river or micro-basin focus and watchdog agenda, to a broader regional integrated resources management view. This paper examines the origins of Participatory Environmental Monitoring and Surveillance Committees in Peru. It also discusses the typology of these committees, and the scope of their work. Furthermore, it looks at the challenges faced by these committees, as well as existing opportunities for mining companies, governments, and civil society. Finally, this study presents a governance model that could contribute to the long-term existence of these committees. This discussion is further informed by the results of a national workshop that took place in October 2016 in Peru, in which over 200 representatives from 22 monitoring committees, government and mining companies participated.

Jan 1, 2017

By Robert L. Somerville

As more phosphate deposits are discovered and new mines are developed, the necessity of critically evaluating various rocks for phosphoric acid production recurs ever more frequently. This need is accentuated by the increasing number of, fertilizer plants being constructed on deep water at various locations to serve world markets and to take advantage of locally-available sulfur or sulfur-bearing ores. A major proportion of all phosphate rock mined is consumed by wet-process plants and this acid in turn is consumed, usually captively, in the manufacture of fertilizer. It is apparent, therefore, that the first question asked by the developer of a new deposit is - How will it work in a wet-process plant? and conversely, when developing a deep water, project, one of the early studies required is - Which of the available rocks shall we use? What is the correct price to pay? How do we compare one rock with another? The economic importance of even minor aspects of these questions

Jan 1, 1966

By I. Iwasaki, J. N. Orlich

The effect of slurry rheology and ball coating characteristics on the abrasive wear of grinding media and the rate of grinding were studied using -10 mesh quartzite in laboratory marked ball wear tests. Pulp viscosity was found to be closely related with both the thickness and physical characteristics of the coating affecting abrasive wear. The packing density of particles at the ball surface was the primary determinant of wear while the grinding rate was more dependent on viscosity and thus the ball coating thickness. The optimum grinding rate was achieved when the coating thickness was about twice the largest particle size.

Jan 1, 1988

By William T. Ingram

Early in the 60's the author served as Chairman of the Engineering Foundation's Coordinating Committee on Air Pollution Research. One of our objectives was the development of a study on the measurement of stack emissions. Three publications of the Foundation resulted from these efforts to focus attention on the stack sampling problem.1,2,3 Two of these were annotated bibliographies covering 197 references. The third reported the results of a workshop meeting at which some 21 individuals from research institutes, industry and government discussed the possible and probable areas of research that would add to or increase the ease, precision and utility of sampling gaseous and particulate matter emitted from stacks. The American Society of Mechanical Engineers has had in its Power Test Codes a Standard Code for Determining the Dust Concentration in a Gas stream4 since 1941, The American Industrial Hygiene Association has published, in its Air Pollution Manual,5 a Section on Stack Sampling. Industry and regulatory agency requirements for stack sampling have utilized some modification of the alternatives in methodology. There has been ho single guide to stack sampling that met the needs of those who have the need to know.

Jan 1, 1970

By J. A. Marts, R. C. Gilmore, S. Saki, J. F. Brune

El modelamiento de la dinámica de fluidos computacional (CFD por sus siglas en inglés) implica la creación de un dominio de cálculo llamado malla o rejilla para resolver las ecuaciones que definen la física del flujo de fluidos. Este proceso comprende a menudo emplear la mayor parte del tiempo en esfuerzos de modelamiento. En un proyecto patrocinado por el Instituto Nacional de Seguridad y Salud Ocupacional (NIOSH), los investigadores de la Escuela de Minas de Colorado utilizaron un enfoque innovador de mallas, el cual permite una fácil adaptación del modelo CFD para adaptarse a una variedad de geometrías de minado de tajos largos ventilados por canales (bleeders) y progresivamente sellados (referidos a menudo como bleederless en los Estados Unidos), con la porosidad y la permeabilidad de la cámara escalables en un amplio intervalo. En este trabajo se presenta la metodología del enfoque de enmallado y escalado junto con las recomendaciones para el uso de modelos CFD en aplicaciones de ventilación para las cámaras en tajos largos. La nueva técnica de enmallado se utilizó para evaluar la función de un retorno hacia atrás en una cámara progresivamente sellada y otra cámara ventilada por canales.

Jan 1, 2014

By S. Amirshenava, S. Nadimi

"Premature and unplanned mine closure can result in significant adverse impacts on the environment and community and need to be managed appropriately. Risk management techniques can reduce the negative impacts and risks of early mine closure. Risk Assessment 3D Model, is an efficient tool to quantify risk. The aim of this paper is to identify the mine closure risks in Choghart iron ore mine, and calculate the overall mine closure risk level. The result shows that 51.4% of assessed risks have low risk level and the overall risk level of early mine closure is low. Keywords: mine closure, risk assessment 3D model, Choghart iron ore mine INTRODUCTION The modern mining life-cycle can be divided into three main stages; exploration, mining (opening and production) and post mining (mine closure, and reclamation). Mine closure is the critical component of the modern mining life-cycle and it refers to the period of time when the operational stage of a mine has permanently ceases (Heikkinen et al, 2008). Planned closure occurs due to the depletion of ore reserves, but sometimes it is premature. Laurance (2006) shows that only 25% of mine closure in the past 30 years was due to resource depletion and in 75% of the cases the mines were closed for the other reasons. Ghanbari et al (2010) demonstrated that 48.6 % of copper mine closure in the past 100 years was due to resource depletion and 51.4 % of copper mines have been closed due to other reasons. The main reasons of premature mine closure are as follow (Laurance, 2006; Ghanbari et al, 2010; Maiti, 2013): • Economic, (low commodity prices or high costs) • Geological, (over-estimation of grade and tonnage) • Geotechnical (adverse geotechnical conditions) • Technical (equipment failure) • Regulatory, due to safety or environmental breaches • Social or community pressures • Closure of downstream industry or markets • Flooding or inrush Minaei Mobtaker and Osanloo (2013) developed a mine closure prediction model based on the data collected from closed iron ore mines in the past 100 years. They showed that economic factors, exhaustion of ore reserve and geological conditions are the main reasons of iron ore mine closure. They treated mine closure as a decision making problem in order to predict the causes of mine closure, including the uncertainties of some mine plan parameter such as iron ore price, production and consumption."

Jan 1, 2016

By C. F. Johnson

Nearly all of the sulphur produced in the world today is converted to sulphuric acid and 49 % is used in the manufacture of fertilizers. In the last few years we have seen the beginning of another chapter in the volatile history of sulphur as the severe shortage of 1963:-67 has been transformed into present-day surplus. Prospects for further aggravation of this situation in the years ahead seem assured. In 1970, western world production showed a rate of increase of 4 -5%, which 1S somewhat less than that of 8% for the period 1963-1967. The rate of growth of consumption dropped considerably in 1968 when the demands of the fertilizer industry fell. During the same period of time, wide-spread demands have been set in motion for a clean environment which indicates that a fundamental change in sulphur supply, demand, and even sources, is likely to result from this upheaval. The sale of sulphur by Poland to the western world has increased and for 1970 was estimated at over one million metric tons. In the next few years, increase in Canadian sulphur supply will stern from two sources;

Jan 1, 1972

By A. B. Cecala

Video technology coupled with datalogging exposure monitors have been used to evaluate worker exposure to different types of contaminants. However, previous application of this technology used a stationary video camera to record the worker?s activity while the worker wore some type of contaminant monitor. these techniques are not applicable to mobile workers in the mining industry because of their need to move around the operation while performing their duties. the Helmet-Cam is a recently developed exposure assessment tool that integrates a person-wearable video recorder with a datalogging dust monitor. these are worn by the miner in a backpack, safety belt or safety vest to identify areas or job tasks of elevated exposure. After a miner performs his or her job while wearing the unit, the video and dust exposure data filesare downloaded to a computer and then merged together through a NIOSH-developed computer software program called enhanced Video Analysis of Dust exposure (eVADe). by providing synchronized playback of the merged video footage and dust exposure data, the eVADe software allows for the assessment and identificationof key work areas and processes, as well as work tasks that significantlyimpact a worker?s personal respirable dust exposure. the Helmet-Cam technology has been tested at a number of metal/nonmetal mining operations and has proven to be a valuable assessment tool. mining companies wishing to use this technique can purchase a commercially available video camera and an instantaneous dust monitor to obtain the necessary data, and the NIOSH-developed eVADe software will be available for download at no cost on the NIOSH website.

Sep 1, 2013

By James Westfield

I welcome this opportunity to appear before you and to review briefly the various health and safety services of the Bureau of Mines available to the mining industry, other than coal, and also to tell of our plans for extending these services to improve safety and health conditions. The Bureau's health and safety activities are basically services by which we attempt to develop and disseminate information on improved techniques in mine accident prevention and promote mine safety education in the mineral industries. Unfortunately, some mining companies, particularly some of the smaller operations, seem to be unfamiliar with these services, The Bureau of Mines is charged by law with the responsibility for inspecting coal mines; other services to the coal mining industry and are provided only on request, Safety inspections and other services that we offer are provided for noncoal mining industries solely upon request.

Jan 1, 1958

"Controlling dust generation and keeping it below permissible limits at the working face of a room and pillar mine is a challenge for mine operators. With the recent changes in the respirable-dust regulation, it has become increasingly difficult. The current most effective practice of dust control at a continuous miner face in an underground mine is the use of a flooded-bed scrubber. A study carried out by the National Institute for Occupational Safety and Health (NIOSH) stated that a flooded-bed scrubber, under its optimum condition, can achieve cleaning efficiencies between 58 and 90 percent. The performance of such a system can be maintenance intensive. Other industries face similar dust control issues. The University of Kentucky partnered with Toyota Motor Manufacturing for the development of a novel wet scrubber for capturing paint overspray, with capture efficiencies in excess of 98 percent and minimal maintenance. The aim of this study is to assess the ability of this novel wet scrubber to capture respirable dust in an underground coal mine. This paper presents the conceptual design and the computational fluid dynamics (CFD) modeling of this novel wet scrubber. It discusses the results of the CFD simulation performed on the novel wet dust scrubber. INTRODUCTION Dust generation from underground coal mining is an inescapable phenomenon. No matter the practices employed, it inevitably occurs. Elevated concentrations of coal dust are potential health and safety hazards. Although dust in an underground coal mine cannot be completely avoided, its influence can be mitigated through good engineering practices. The effect of dust on the health of mining personnel has had a significant impact. The prolonged exposure of airborne respirable dust (< 5 µm) can cause coal workers’ pneumoconiosis (CWP), silicosis, emphysema, and chronic bronchitis, collectively known as black lung (U.S. Department of Labor, 2014). According to the National Institute for Occupational Safety and Health, black lung has killed more than 10,000 miners between 1995 and 2004 (NIOSH, 2008). In addition to being a health issue, coal dust is also a safety issue to the underground coal miners. The generated dust, if not captured, is dispersed into the mine air through the ventilating air and deposited downwind on the return entries’ surfaces. In the event of a methane explosion, the coal dust, if insufficiently diluted with rock dust, triggers a coal dust explosion which is much more severe than a methane explosion and causes more damage (Kenneth et al, 2006). The Jim Walters No. 5 Mine and the Upper Big Branch Mine disasters which together killed 42 people and resulted in damage worth millions of dollars in property are the examples of coal dust explosions (U.S. Department of Labor, 2001 & 2010)."

Jan 1, 2016

By Nicholas C. Lias

Quartz crystals are the raw material from which are made the crystal units utilized in filters and oscillators so vital to the performance of all long distance communications systems. These devices act as the heart of equipment that permits a single telephone cable to carry hundreds of conversations simultaneously. Quartz crystals are of value in communications because of this piezoelectric nature, that is when an electric signal is applied to the quartz, there is a resulting mechanical motion and conversely, a mechanical stress results in an electrical output signal. A plate cut from a quartz crystal will oscillate at some specific frequency, which is determined by the physical dimension of the plate. During the early stages of telephony, all quartz plates were cut from natural quartz, which was imported mainly from Brazil. Since the source of this important raw material was based upon a foreign supply which is located at a great distance from the user and could be vulnerable in time of a national emergent, it became necessary to maintain a large inventory of this strategic material. Also due to the considerable cost of natural crystals of a size and quality suitable for Bell System use, an investigation was made by Bell Laboratories into the possibility of developing a substitute material. The effort was successful and led to a joint development program between Bell Laboratories and Western Electric. This program brought about the design of manufacturing facilities capable of producing large quantities of cultured quartz at Western&apos;s Merrimack Valley Works, No. Andover, Massachusetts.

Jan 1, 1973

By P. L. Sibrell

Previous research by the U.S. Bureau of Mines showed that autoclave cyanide leaching of used automobile exhaust catalysts for recovery of platinum group metals (PGM) was technically feasible. This work involves a more detailed investigation of the chemistry of the dissolution of PGM in cyanide solutions. The PGM species in solution identified by ultraviolet spectroscopy. Pt and Pd cyanide complexes were square were The planar in geometry, while the Rh complex was octahedral. The rate of dissolution of the PGM was also investigated using a rotating disk technique. Dissolution rates increased in the order of Rh, pt, and Pd, respectively.

Jan 1, 1994

By A. Toulet

Mining in Mexico has an immensely long tradition. In his first letter reporting to his sovereigns from Mexico in July 1519, Hernan Cortes wrote, "To our mind it is probable that this land contains as many riches as that from which Solomon is said to have obtained the gold for the temple ... " 1 But not only precious metals drew his attention; in 1524, short of tin needed for casting guns, he found it in Taxco. As an added bonus, those who went to find it "came upon a vein of iron which according to experts is of exceeding richness." 2 Since then, the mines of Mexico have yielded up enormous amounts of mineral and continue to do so. Mexico is one of the ten principal producers of minerals world-wide both in production volume and diversity. 3 Tens of thousands of tons of iron, sulphur, and coal come from its earth annually; it is the world&apos;s second largest producer of barite; third of antimony, fluorite, and graphite. 4 Copper, zinc, silver, molybdenum, arsenic and cadmium and others are wrested from its mines. The wealth is there; but maximizing its potential requires investment, technology, and markets that the government cannot itself provide. Thus mining, since the Mexican Revolution severely restricted by both law and policy, today looks to private investment to develop its potential. Beginning in 1989, Mexico&apos;s government cautiously moved to liberalize private sector involvement in mining; 5 using the experience gained from these initial regulatory changes, the current new Mining Law was adopted in 1992 6 and new Regulations were promulgated in 1993. 7

Jan 1, 1994

By D. L. Monroe

Technical service is assuming an increasingly important role in the sale of asbestos fibre,, Manufacturers are examining raw materials more closely than ever before in order to, obtain the most efficient usage in their processes. Asbestos is one of the more difficult materials to evaluate and consequently has been are of the last to be subjected to evaluation. The main problem encountered in the evaluation of asbestos fibre is that minor differences in grade and texture are not shown up by chemical analysis, and are identified only by specialized physical analyses or actual production use. However, such minor differences become more critical as manufacturing processes are made more efficient, and many purchasing agents and plant chemists are applying a closer scrutiny to their supply of raw asbestos fibre. Many processes have been formulated around grades and qualities of asbestos fibre, which were standard some time ago, but which may now be subject to modification and improvement.

Jan 1, 1959

By P. A. Korpi

In March of 1978 the first set of Angular Spiral Liners utilized in grate discharge ball mills for wet grinding was put into service in the San Flanuel Concentrator of Flagma Copper Company. The use of these liners has decreased grinding media consumption by 19.2% and grinding energy consumption by 15.8%. In addition a 1.1% increase in grinding throughput is being realized through the use of the system. This paper describes the Angular Spiral Lining System and reviews the test program at the San Manuel Arizona Concentrator. Operating parameters are discussed in addition to the current testing program to futher optimize the system.

Jan 1, 1982