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By Pierre Mousset-Jones

I wish to submit this discussion item on an article published in the August issue of MINING ENGINEERING by Wala and Altman on the use of canonical diagrams for mine ventilation networks. The advent of computer graphics and plotting has enabled complex underground mine layouts to be displayed and plotted in a variety of three-dimensional formats that very closely represent the actual mine layout. This enables the ventilation engineer, who is familiar with the mine, to display the network pressures, quantities, resistances, and fan locations in a way that can be understood by everyone working at the mine. This is important if the ventilation engineer needs to discuss changes in ventilation with production personnel, or escapeway procedures with union personnel. While I can see some of the potential advantages in the canonical ventilation network diagram described by Dr. Wala, it appears to me that the fact that the diagram has no visual equivalence with the actual mine layout means that most mine personnel will find such a diagram almost incomprehensible. The authors have alluded to certain advantages with the canonical diagram. However, I find it difficult to see that these outweigh the fact that almost everything listed can be duplicated in isometric diagrams, and in a manner that is easily understandable to everyone in the mine from the miner to the mine manager. Perhaps the authors could show a clear example comparing an isometric with a canonical portrayal of a mine network showing the information that is immediately available from the canonical network that is not obvious in the isometric diagram. There is in this country a severe problem with the need for ventilation engineering and expertise to be used and accepted by mine management as a necessary part of mine planning. It seems to me that to introduce the requirement for further explanation so that management can understand a canonical network display will hinder more than help the recognition that ventilation engineering needs at so many mines in this country. However, I can see that the canonical approach does have its place in assisting the practicing mine ventilation engineer, wherever he or she exists in the organization chart for a typical mine. In this case, could the authors please indicate the availability of the computer program to compute and plot the canonical diagram for a mine ventilation network.

Jan 1, 1990

By Pierre Mousset-Jones

I wish to submit this discussion item on an article published in the August issue of MINING ENGINEERING by Wala and Altman on the use of canonical diagrams for mine ventilation networks. The advent of computer graphics and plotting has enabled complex underground mine layouts to be displayed and plotted in a variety of three-dimensional formats that very closely represent the actual mine layout. This enables the ventilation engineer, who is familiar with the mine, to display the network pressures, quantities, resistances, and fan locations in a way that can be understood by everyone working at the mine. This is important if the ventilation engineer needs to discuss changes in ventilation with production personnel, or escapeway procedures with union personnel. While I can see some of the potential advantages in the canonical ventilation network diagram described by Dr. Wala, it appears to me that the fact that the diagram has no visual equivalence with the actual mine layout means that most mine personnel will find such a diagram almost incomprehensible. The authors have alluded to certain advantages with the canonical diagram. However, I find it difficult to see that these outweigh the fact that almost everything listed can be duplicated in isometric diagrams, and in a manner that is easily understandable to everyone in the mine from the miner to the mine manager. Perhaps the authors could show a clear example comparing an isometric with a canonical portrayal of a mine network showing the information that is immediately available from the canonical network that is not obvious in the isometric diagram. There is in this country a severe problem with the need for ventilation engineering and expertise to be used and accepted by mine management as a necessary part of mine planning. It seems to me that to introduce the requirement for further explanation so that management can understand a canonical network display will hinder more than help the recognition that ventilation engineering needs at so many mines in this country. However, I can see that the canonical approach does have its place in assisting the practicing mine ventilation engineer, wherever he or she exists in the organization chart for a typical mine. In this case, could the authors please indicate the availability of the computer program to compute and plot the canonical diagram for a mine ventilation network.

Jan 1, 1989

By Leonard Harris

Most of those involved in the mining industry are aware of the negative feelings that the well-informed citizens of this country, also known as the American public, have for the industry. As noted in an issue of Mining World News, “The general public perceives mining as dirty, noisy, destructive and belonging somewhere else.” The same theme was raised at a conference in Scotland in July 1991. It was noted there that mining has an unattractive public image around the world “as dirty, dangerous work that pollutes and degrades the environment.” Why is this? Why does mining have such a bad rap? I’m afraid that some of the blame rests with the mining industry itself - both in the past and in the present. Hopefully, we can do something about this in the future. And hopefully, the information here will help the reader to spread the word to offset the negative messages being issued almost daily by industry foes. I hope this will become more than just the words of another miner talking to miners and their friends. In the past, belching smokestacks and polluted streams and waterways were common sights. Today, the negative results of mining operations can also be seen in the form of waste dumps, leaked acid mine waste water and dust blowing from tailings piles. Some will argue that mining did nothing illegal in the past, and that all the regulations in force at that time were carried out to the letter. That may be so. The fact remains, however, that mining did these things, and the evidence is very clear in many parts of the country. It is visible to the well-informed citizens, in spite of the fact that many mine sites have been cleaned up and new technologies, such as flash smelting, dump leaching, pressure leaching and bioleaching, have greatly overcome many of the pollution problems. What is not so visible is the importance of the mining industry in our daily lives. Not long ago, knowledge about our non-renewable mineral resources ranked low on the list of qualifications for being a well-informed citizen. Events during the past two decades have changed this scenario. Politicians, writers, newscasters, economists and administrators, as well as the ‘public,’ are expressing opinions and forming judgments on oil company profits, desecration of landscapes, waste disposal sites and pollution by the extractive industries.

Jan 1, 1992

By 000-000-604

HISTORIACAL INTRODUCTION Mineral processing has three principle branches, to quote Taggart, "Ore Dressing, which comprises the methods of separation of solids in inorganic crude by means which do not affect substantial chemical change; Extractive Metallurgy, which utilizes chemical reactions for separations of constituents from solids in inorganic crude; and, Fuel Technology, which employs both physical and chemical methods for separating and rearrangement of liquid gaseous and solid components in crude oil and natural gas, tar sands, shale oil, or coal." The scope of this handbook covers the first two classifications, that is, "ore dressing" and "extractive metallurgy," which have been combined in one term: "mineral processing." For a brief history of the development of mineral processing, one could well refer to the Introduction, Sec. I of the Handbook of Mineral Dressing by Taggart, Froth Flotation, Principles of Mineral Dressing by Gaudin, and the original Richard's Ore Dressing, volume No. 1, first published in 1903-1905. In these references and the references given in them a coverage of the history of "ore dressing" can be found and studied at the reader's leisure. For the history of extractive metallurgy as well as ore dressing, the bibliography in General References, taken from a History of Ex¬tractive Metallurgy by F. Habashi, will give a good background for those who are interested in more detail on the history of metallurgy in general. Mineral processing covers a very wide field as is illustrated by the topics discussed in Part II of this handbook and dates back to the early history of man which started with the production and use of native minerals such as gold, silver, copper, mercury, and meteoric iron which were washed or picked from deposits on the surface of the earth and worked because of their malleability. Later, melting was discovered and then it was possible to cast objects of these metals, excluding mercury. The discovery of a method for reducing the metal¬lic oxide probably was developed from melting fragments of oxides or roasted sulfides with charcoal, so that the native metal could be produced in simple blast furnaces such as are used today in rural parts of Spain, China, and elsewhere. Eventually, it was learned that iron could be readily worked when hot, which resulted in its replacing bronze for tools, weapons, and cutlery. Carbon dating and correlation with the Brittle Cone pine has

Jan 1, 1985

By Daniel Hodouin, Claude Bazin, Sami Makni

SCOTT COULTER: Thanks, Eric. Thank you all for coming. Our first speaker today is Claude Bazin. Claude received a degree in metallurgical engineering in 1980 from Laval University in Quebec. He worked for a short time in a mineral processing plant and then returned to Laval to complete graduate studies in the field of process modeling and control. He obtained his master's degree in 1983 and his Ph.D. in 1990. In 1987 he joined Brunswick Mining, New Brunswick, as research metallurgist and subsequently process control engineer. In 1990 he joined Helzfield Mines, New Brunswick, as senior metallurgist. In 1991 he accepted a position of professor at the department of mining and metallurgy at Laval University, a position he is still holding. He's a member of the CIM, TMS, and the Society for Mining, Metallurgy, and Exploration. Claude's topic today is "On-Line Material Balance for Flotation Plants." INTRODUCTION CLAUDE BAZIN: During the last two decades, the on-stream analyzer (OSA) has gained the stat& of key instrument for the control of flotation plants. The OSA is currently used in almost every sulphide flotation plant (Leroux and Franklin 1994), and its application to oxide mineral flotation plants is increasing. The OSA assays are sent to the flotation operators via an operator console or to control loops of various degrees of complexity (McKee 1991) implemented in a distributed control system (DCS). Operators and/or controllers take control actions based on these assays to ensure an adequate operation of the plant. Although this application pays off very rapidly for the purchase of the OSA, one could ask, "Could we get more from the OSA?" Some plants reported the use of OSA measurements for process optimization (McKee 1991). The optimization strategy is based upon economic indices calculated from metal recovery using the 2-product formula (Wills 1992, p. 124). The 2-product formula is sensitive to measurement errors in the assays and can lead to considerable scatter in the calculated indices (Hodouin et al. 1993). Least squares algorithms provide a robust alternative to filter out measurement errors (Spring 1992). This paper presents some applications of a recursive least squares algorithm that provides real-time estimates of the mass flow rates within a flotation plant using OSA and mass flow rate measurements.

Jan 1, 1998

By John L. Bolles

The mineral processing engineer must have some knowledge of mineral identification, and the greater his knowledge in this field, the greater will be his potential to do his own specialty well. Most metal-bearing ores and industrial minerals require processing of some kind to produce a salable product or a material suitable for further processing. The types of treatment are many, but each one is aimed at separating a mineral or family of minerals from others. Obviously, then, it is basic to all mineral processing to identify the minerals present in the raw material and in intermediate and final products resulting from processing. Very often the mineral processing engineer will enter planning while exploration of a mineral prospect is going on. He will examine hand specimens, drill cores and cuttings, bulk samples, and materials in place. He must identify the valuable minerals, their occurrence and associations with other minerals, and the identity of diluents or host rock. An exact and detailed knowledge of the raw material will usually suggest the treatment processes that should be investigated in the development of the most suitable scheme for that particular raw material in that particular location. Physical properties of a mineral often lead directly to a process for separating that mineral from others. Some well-known examples of these are: magnetic separations for such minerals as magnetite, rutile, ilmenite; gravity separations for gold, silver, galena. cassiterite; flotation separation for most sulfides; distillation of mercury from cinnabar; and selective dissolution in specific solvents such as halite or sylvite in water, gold and silver in cyanide solutions, copper oxides, carbonates, sulfates and silicates in dilute sulfuric acid. These processes and many others are described in detail elsewhere in the Hand¬book and so it is not appropriate to give details here, except to emphasize that processing is aided greatly by complete mineral identi¬fication. Developing a treatment scheme for a new mineral discovery is an exciting assignment fag the mineral processing engineer, but much more of the usual work relates to quality control in existing plants. Here too, mineral identification is important. Some processing is aimed toward producing an end product which will meet exacting specifica¬tions regarding purity or allowable diluents. In this situation it is vital that contaminants be identified so that the process can be adjusted

Jan 1, 1985

By David A. Gulley, William A. Vogely

INTRODUCTION The Scope of the Chapter This chapter discusses environmental regulation and closely-related public policies associated with mineral development in the United States. This chapter outlines the nature, extent, and amelioration of secondary effects of mineral development. It sketches the policy foundations of regulation; discusses the implementation of environmental law; describes land use conflicts and land management regimes; and surveys the costs and benefits of environmental regulation. Since regulations are subject to frequent change, the chapter emphasizes basic factual and conceptual material, rather than specific regulations. The goal is to familiarize the reader with the general nature of environmental impacts and mitigation which arise in the minerals industry, and with the issues surrounding the regulation debate. The chapter is organized as a series of sub- chapters. The first of these is a discussion of the conceptual foundations of regulatory policy. The second section summarizes the principal federal environmental statutes, and the implementation of such regulation. Following that, the third section summarizes the current state of knowledge regarding the types of environmental impacts associated with mineral development. This discussion, organized in a format similar to that used in environmental impact statements, can be thought of as a guide to reading and understanding such statements. Next, the fourth section surveys studies of the costs and benefits of environmental regulation. 'These empirical studies are evaluated in terms of the framework developed in the first section of the chapter. In the fifth section, the discussion turns to federal, state, and local approaches to land use control and siting, and the economic analysis of such conflicts. Included are discussions of the two principal forms of public lands mineral entry, the 1872 location patent system and the 1920 leasing approach. CONCEPTUAL FOUNDATIONS OF REGULATORY POLICY David A. Gulley The Role of Regulation in a Market Economy What is Regulation?: Regulation is the intervention of government in the activities of the private market. In a market society, the private sector is presumed to be the most appropriate economic agent. Given this presumption, regulation generally begins with a demonstration of persistent problems under laissez-faire in a given context. Environmental and related regulation occurs because the public believes the free market does not properly value environ- mental quality. In this section, concepts are advanced to aid the reader in understanding the government's role in this respect.

Jan 1, 1985

By Alexander N. Winchell

"Location. The Cuyuna iron district extends from the region of Kimberly, near the Center of Aitkin County, Minnesota, south-westward through Deerwood, Ironton, and Brainerd, across Crow Wing and Todd counties, across the Mississippi River, and for an unknown distance farther southwest in the same direction. It is known that the Huronian rocks, in which the ores of the Cuyuna district are found, reappear near the western border f Minnesota, but no ores have been found in this region. The district has a length of more than sixty miles, but the more important portion as now known 'is confined to Crow Wing County in an area which is less than thirty miles in its longest dimension. The commercial headquarters for the district are in the city f Brainerd, on the Mississippi River.History. The discovery of iron ore in the Cuyuna district was accomplished with no aid from surface outcrops, but solely through the use of the dip needle. The mantle of glacial drift overlying the iron formation varies from twenty-five to 359 feet in thickness, and it was by means f the magnetic attraction of the iron bearing rocks that their presence was discovered with the dip needle by Cuyler Adams, about 1895. The general geologic map of Minnesota, published by the State Geological Survey in 1909, showed the extension of the Huronian rocks of the Mesabi district passing through this area. Two years later, Leith published a sketch showing the hypothetic extension of the iron bearing formation through the same area. The first drilling was done in 1903, near Deerwood, Minn., by Cuyler Adams, and exploration was continued to the present time in increasing amount. The Northern Pacific Railway extends throughout the length of the district and affords an easy outlet for the ores. The Soo Line Railway completed a spur into the district in 1910. Both roads carry the ore to the docks at Supe¬rior, Wis., the average haul being about ninety miles. Shipments began in 1911, the Kennedy mine being the first producer. By 1918, the number of shippers reached twenty-seven, with a total output of nearly two and one-half million tons for that year."

Jan 1, 1920

By Remo Grandori

"INTRODUCTIONDouble Shield TBMs were introduced in the market in the early seventies with three main targets:• Increase the TBM performances in term of advance per day thanks to the ability to erect a segmental lining simultaneously with the excavation phase.• Be able to advance through unstable and disturbed rocks under the protection of the shields• Provide a finished tunnel by installing a precast lining as the TBM advance.In 2003 SELI developed the design of the Double Shield Universal (DSU) TBM as an evolution of the original Double Shield TBM design.This new TBM design was targeted to improve: the TBM capability to advance through squeezing/converging rock formations under high cover, the telescopic joint design (allowing by such to operate the machine in double shield mode in very weak rock), the capability of the TBM to investigate and treat the ground around and ahead of the tunnel face.In the same lapse of time Single Shield TBMs, originally utilized for soft ground tunnelling, extended progressively their range of application to mix rocks and finally to hard rock tunnelling with increasing performances.This also thanks to the substantial reduction in the installation time of the segmental lining ring that contributed to minimize the TBM stand by time between two consecutive boring strokes.Today the choice between the two types of TBMs needs to be carefully evaluated project by project since one type of TBM may “prevail” in certain geologies and diameters and vice versa.THE VISHNUGAD PIPALKOTI TUNNELThe Vishnugad Pipalkoti Tunnel is part of the 444 MW Vishnugad Pipalkoti Hydro Electric Project (VPHEP) on Alaknanda river in Uttarakhand (India).The Owner is the Indian electric company “Tehry Hydro Development Corporation” (THDC) and the World Bank finances the project.The Headrace Tunnel total length is 13.4 Km and a section of about 12,3km will be excavated by TBM by SELI Overseas (Italy) in subcontract to HCC (India) the General Contractor for the project. The TBM will be delivered ex workshop in March 2016 and it is foreseen to start boring in the second half of 2016.Figure 1 below shows the location of the project and the following Table 1 summarizes the geometrical characteristics of the TBM tunnel."

Jan 1, 2016

By Jr. Smith

Borates have been mined in the desert areas of California and Nevada for more than 100 years. To about 1890, playa surface mining provided the chief sources of boron minerals. Underground mining of colemanite and later of borax and kernite was predominate until about twenty years ago. Open pit mining of the large deposits of borax and kernite near Boron, California has been most significant for the past twenty years. Mining of colemanite in the Ryan, California area, near Death Valley, began in 1907. Following the discovery of the large deposits in the Boron area (about 1957), mining in the Death Valley area became nearly nonexistent. Only small tonnages were mined for special uses. Little mining was done in the Boraxo area near Ryan. The first claim was made in about 1915 In 1960 the area became the property of the Kern County Land Company, which was acquired by Tenneco Oil Company in 1967. In 1976 the various borate properties and claims in this region were acquired by American Borate Corporation. The open pit mine is now approximately 400 feet (121.9 m) deep, 3000 feet (914.4 m) long and 1000 feet (304.8 m) wide. The borates in the Boraxo pit consist primarily of three minerals. These are about 50% coiemanite (C2B6O11' 5H2O), about 40% probertite (NaCaB5O9.5H2O), and 10% ulexite (NaCaBcO9.8H2O). The colemanite, along with boric acid and high-grade coiemanite ore from Turkey provide the only sodium-free borates for production of textile grade fiberglas. When heated to its decomposition temperature, colemanite decrepitates to a fine powder. This provides the basis for the concentration process. The gangue minerals in this deposit are primarily calcite and clays, including bentonite. The ore body has a very low arsenic content.which is a desirable feature. Test work had been done with samples prior to the results discussed herein. This paper will discuss results of test work which were the basis for erection of a plant, and the subsequent plant operations.

Jan 1, 1978

By James S. Browning

In 1975 bituminous coal and lignite production in the United States reached an all-time high of 637 million tons, an increase of 6 percent over production in 1974. The output, valued at $11.9 billion f.o.b. mines, was produced at 5,100 mines in 24 states (6). Coal mining is the largest mining industry in Alabama. Production from Alabama's mines in 1975 was over 21 million tons, and present projections forecast a steady increase in production, with tonnages almost doubling by 1985 (5). Of the total quantity of coal produced, about 16 million tons were consumed in electric power generation and the remainder was used for metallurgical coke production, extraction of chemicals and petroleum based products, and power for industry. The fact that 75 percent of Alabama's power is generated by burning coal attests to the importance of this fossil fuel to the State. Approximately 14 million tons of coal were produced by strip-mining methods in Alabama during 1975 and about 7 million tons were produced by underground mining during the same period. Surface mining is expected to continue at about 14 million tons per year, but by 1980 underground coal mining is expected to increase to about 25 million tons (3). About 7 million tons of surface-mined coal in Alabama is subjected to some means of washing or cleaning. The methods used are screening accompanied by heavy media separation, jigging, tabling and flotation. Some of the simpler approaches employ screening and jigging, or tabling. Except where flotation is used, the screen undersize fraction (finer than 0.25 inch) is rejected, with the result that 10 to 15 percent of the coal is lost. Thus, in the State of Alabama an aggregate of about 1 million tons of coal is wasted annually in the fines which are impounded from treatment of surface-mined coal. The use of the Humphreys spiral to concentrate fine coal was practiced as early as 1947. At that time the Hudson Coal Company (1) used Humphreys spirals to concentrate anthracite fines. In 1950, the use of spirals to treat fine-size

Jan 1, 1977

By William Gleason

"More than 6,300 people converged on the Colorado Convention Center for the 2017 SME Annual Conference and Expo and 119th National Western Mining Conference in Denver, CO on Feb. 19-22. Many of them crammed in to hear Douglas Silver deliver the keynote address to the conference.Silver is a portfolio manager for Orion Mine Finance, a private-equity fund focused on providing funding to advanced-stage base and precious metal projects and is one of the most respected voices in the field of mineral economics. Prior to joining Orion, he served as chief executive officer and chairman of International Royalty Corp., a global mineral royalty company, which he founded in 2003 and sold in 2011.Those who were hoping that Silver would deliver at least a bit of optimism during his 90-minute presentation got what they came for from the talk titled, “When are commodity prices going to rebound?”It marked the second time Silver has presented the keynote address to SME, the first was in 2008 and was delivered during the height of mining’s super cycle (ME, June 2008). In his 2017 address, Silver looked back on the previous 10 years and the massive contraction of the global economy that resulted from the great recession that began near the end of 2008.It has been a challenging time for the mining industry. About US$1.4 trillion was lost in the global mining stocks from 2011 to Jan. 6, 2016. Major mining companies exceeded $60 billion in write downs between 2012 and 2013 and investors lost confidence in the sector, putting the global mining industry into a bear market that has taken mining equities to historic lows.However, that was then and this is now.Using numerous examples, including rising commodity prices, a steady decline in the U.S. unemployment rate, increases in discretionary income and the Dow Jones Industrial Average, which topped the 20,000 mark for the first time ever in February, Silver theorized the current down cycle is near its end and the demand for metals and other commodities will see a sharp increase by 2025. He also noted that investors are beginning to rotate back into mining equities."

Apr 1, 2017

By Guillermo P. Salas

The Consejo de Recursos Naturales No Renovables of the Mexican government entered into an agreement with the United Nations in 1964 for the mineral exploration of a large area in Estado de Sonora, Mexico. The agreement called for a systematic exploration for copper in northern Sonora based on photogeologic mapping, aerial reconnaissance, and geochemical stream sediment sampling. The UN-CRNNR investigations resulted in the detection of anomalous copper values in sediment from the Arroyo Cruz de Cafiada. The anomaly was followed upstream to its source, which ultimately proved to be the La Caridad ore body (see Fig. 1). Soil copper and molybdenum values were found over a large area, and further detailed geologic and geophysical investigations were instituted of the anomalous area. David Coolbaugh was largely responsible for the follow-up work. An induced polarization (IP) survey found a roughly circular region of "highs" that coincided with a high soil copper anomaly. The circular anomalies ringed the topographic feature that ultimately was found to contain the Caridad ore body. Soil geochemical copper response over the ore body was subdued, because the soils were derived from a leached capping, whereas leaching in fringe areas that contained less veining was less intense. The ore body was also ringed by the typical high pyrite zone, and this was the anomaly detected by the IP survey. The UN began drilling in the fall of 1966. Eleven holes tested the IP-Cu geochemical high, but none were of commercial interest. The project was returned to the Consejo and was reviewed in the field by G.P. Salas and V.F. Hollister. It was found that the leached capping had not been tested by the past activities, and the Consejo elected to explore that area in 1967. The capping was evaluated by Salas and Hollister and drilling by the Consejo began in 1967. Commercial grade ore intercepts were found in the first hole. The Consejo drilled nine holes, of which eight were commercial. At least 90.7 Mt (100 million tons) of 0.8% copper were indicated by the Consejo in eight holes. The lesson learned in this discovery is that evaluation of leached capping is an important guide to exploration. The general-

Jan 1, 1991

By Omar A. Muhtadi, David A. Milligan

7.1 INTRODUCTION The circulating fluid (generally an aqueous cyanide solution) is the major active component of heap leaching. This solution extracts precious metal from the heap and is then processed to recover the precious metal. The solution continuously recycles through the heap to recover more precious metal. With each cycle through the heap, water and chemicals are lost. Make-up water and chemicals must be added to balance losses from evaporation, seepage, entrainment, and chemical reaction in the heap, as well as any other processing losses. Adding more water than needed can result in a build-up of water as inventory in the various ponds and can eventually require that water be discharged from the operation. This is an extremely undesirable condition, and can often be very expensive in both investment in water treating facilities and operating costs. Most heap leach facilities operate under a zero discharge permit; thus, a situation requiring water discharge can result in permit violation. Chemical solution control must be managed to maintain the optimum pH, dissolved oxygen content, and cyanide content, while preventing "scaling". Calcium-based precipitation is a common scaling problem in mill reclaim waters. A buildup of these deposits can result in severe reduction of water flow, loss of pump efficiency and eventual interruption in metal production. In addition, problems of plugged sprinkler heads, blinded leach pads and fouled carbon (in carbon recovery systems) can be and often are experienced when scale control is not maintained. The remainder of this chapter discusses chemical solution control and scaling prediction/prevention in the context of a "closed" system. Sizing of ponds to accommodate precipitation and runoff, collection systems, and other similar design considerations are not discussed here. These topics are deferred to later chapters, e.g. Chapter 10 considers design of collection systems while Chapter 12 discusses pond sizing. 7.2 CHEMICAL CONTROL Chemical composition of the circulating solution must be controlled by the operator if the heap leaching process is to be successful. The primary or essential chemical control parameters in any heap leaching operation are:

Jan 1, 1988

By Joseph Matoney, B. K. Parekh

INTRODUCTION The term "dewatering" refers to removal of water from coal. Water associated with coal can be categorized as "free or surface" and "inherent or chemically bound" moisture.' The free moisture is found on the surface of coal, in capillaries and small spaces between two or more particles. The inherent or chemically bound water is found in the interior of the coal and as part of coal structure. A significant amount of free moisture can be removed by mechanical dewatering techniques. However, inherent moisture can only be removed by applying energy intensive techniques, e.g., direct or indirect heating. Moisture in the coal offsets some of the benefits of coal cleaning. Extra water in clean coal adds to extra cost in transportation, heat lost during vaporization, and plugging of chutes. From a utility perspective, a 1 % increase in moisture can offset a 4.5% decrease in ash.2 Mechanical dewatering can be classified into two major process categories according to the principles involved, namely, 1. Sedimentation-liquid is constrained and particles move freely. 2. Filtration-particles are constrained by a medium and the liquid flows through. Each of the process categories is composed of various separation techniques shown in Fig. Equipment currently being used by the mechanical dewatering of coal of varying size ranges and final moisture content is illustrated in Fig. 8-2. This figure indicates that sizes larger than 13/, in. (37.5 mm) present no particular dewatering problem. Shaker screens of the very crudest types and designs are capable of producing these sizes at low surface moistures. High-speed vibrators are used for the intermediate sizes and can be used for smaller sizes down to 0.02 in. (0.5 mm) if high moistures (15% surface moisture or greater) can be tolerated in the product. Usually, however, the vibrator is not used below 3/, to 3/, in. (9.5 to 6.3 mm) because of the moisture associated with these fine sizes. At this level, centrifugal force is usually employed to aid dewatering. Centrifuges of various types and designs are used practically

Jan 1, 1991

By S. Johnson

Introduction The mining of aggregates underground has grown steadily over the last 25 years. Growth has come in both production volume and in the importance this segment of the industry is playing in the continuing supply of construction aggregate. Underground aggregate mines will continue to grow in both number of operations and complexity, as the replacement of zoned reserves in metropolitan areas becomes crucial. This growth will result in a shortage of qualified mine managers, possibly limiting the success of these facilities. The aggregate industry will have to modify current practices in order to meet the growing demand for this specialized skill. Segment Growth Underground mining for aggregates is not a new idea. Martin Marietta has been operating underground mines since 1969, and currently operates 16 underground mines ranging in size from 250,000 tpy to 2,500,000 tpy. These mines represent less than 4% of the total number of operating locations, but contributed 9% of the annual production in 2004. Though they range in size and production capacity, the importance is evident. The 2000 United States Census revealed several trends that are of interest to the aggregate mining industry. For the period 1990-2000 the U.S. population grew by 33 million or 13%. There were nine major metropolitan areas with a population of five million or more. These nine areas accounted for 30% of the total U.S. population. More significant was the fact that the population growth in these nine metro areas was 25% of the growth for the entire country. These statistics tell us that the population is expanding in these major metropolitan areas at a staggering rate. The same thing is happening to some degree in every population center. Population growth increases the demand for local aggregate while reducing the available area to mine that aggregate. The need for an economical supply of aggregate to support community expansion is a problem that will grow as older quarries are mined out and closed. This will be an issue that communities of all sizes will have to deal with. A reliable and cost effective supply of quality aggregate is crucial to support community expansion.

Jan 1, 2006

By Emmet K. Oslen

Kaiser Steel Corporation, the pioneer steelmaker on the Pacific Coast, was founded by the late Henry J. Kaiser. In 1944 the Company purchased from the Southern Pacific Railroad an iron ore property 200 miles east of Los Angeles known as Eagle Mountain. Today the domestic operation of Kaiser Steel Corporation consists of the iron mine at Eagle Mountain; two coal mines, one each in Utah and New Mexico; an integrated steelmaking complex at Fontana, California; and several steel fabrication and erection facilities along the west coast. Kaiser Steel also has interest in Hamersley Iron, Ltd., Australia, and Kaiser Resources, Ltd., British Columbia. Eagle Mountain Mine is located about 80 miles east of Palm Springs and adjacent to the southeast corner of Joshua Tree National Monument. The area is one of the most arid in the world averaging only two inches of rain annually. Geologically, the mine is at the western edge of the Basin and Range Province which covers about one-half million square miles of the western United States. The Province is typified by north to northwesterly trending fault block mountain ranges separated by sediment filled valleys, Production has totaled over 82 million tons of finished products since the first shipment in June, 1947. Over 500 million tons of material have been mined from the deposit to date. Eagle Mountain Mine is noted for the pioneering use of the largest and most up to date equipment to mine and process its ore. In 1961 Eagle Mountain received the first fleet of 100-ton haulage trucks in the mining industry. There were thirteen semi-trailer units in the fleet. The first 12 to 17-yard size shovel in the mining industry was placed in operation at Eagle Mountain during 1962. Rotary drilling was introduced at Eagle Mountain in 1954 to replace churn drilling. Eagle Mountain was the first major mine to use metallized slurry when three aluminum slurries were introduced for primary blasting in 1962.

Jan 1, 1972

By S. C. Chelgani

The Thor lake deposit is a world class resource of rare earth (REE) metals and minerals in Canada. Development work to optimize a REE mineral recovery process flow sheet is underway, however, given the ore mineralogy; the developed reagent scheme is relatively complex. As part of a research project, micro flotation tests were conducted on a feed sample in order to examine factors affecting stream partitioning. SEM-EDX was performed to evaluate variability in grain composition between streams (concentrate and tails) and TOF-SIMS surface analysis was used to determine statistically significant differences in surface species particularly related to potential activation (or depression) of the examined mineral phases. SEM-EDX analysis reveal that the concentrate has a significantly higher proportion of REE bearing grains (carbonates and phosphates) relative to the tail (almost none were identified). Spectral fingerprinting by TOF-SIMS has allowed for the identification of all reagent species investigated. Reagent signal intensity discrimination on test stream mineral surfaces was observed by the TOF-SIMS analysis using reagents at plant concentration levels. TOF-SIMS analysis confirmed that REE bearing grains reporting to the concentrate are doing so in response to collector attachment whereas grains reporting to the tail are doing so in response to a lack of collector and/or in combination with the presence of the depressant. The surface analysis of gangue phases reveal a similar reagent discrimination; the signal intensity of collector species was significantly higher on the concentrate samples relative to the tails while depressant species were significantly enriched on the surface of the gangue phases in the tail samples. A detailed evaluation of the surface species representing the various reagents used in flotation scheme revealed a distinct competitive relationship between two of the reagents. The surface analysis identified that when used in concurrently, there appears to be a negative feedback resulting in a significant reduction in loading for several of the collectors on grains reporting to the concentrate. An evaluation of the effect of reagents on REE mineral in pilot plant is currently under way. Key words: Rare earth minerals, Flotation, Surface chemistry, TOF-SIMS, SEM-EDX

Feb 27, 2013

By D. W. McGlashan

[Becaune ad ;the extennive nwrgace anea od u.X chopRex2 in emmiom, emuhion dRokdtiun oddeh poaaibWa don ;the necove/ry ul; BinQey divided minmcd pa~LL&a, Swr~aC;tavu% mu2 akab&ze ;the emu-bion and poan an an ad~i&y don ;the dahed mina&. OZhm hpohtant acto oh me ;the naAwre od ;the em&iun inghedied, ;the nQRaLLve volwna 06 the colz;tinuoun and dincon;tinuoun phaa, ;the change aign bonne by the dnuplm ad the o.X phae, ;the z&a pu;tenticd od ;the dahed minmd, the ~olubRe am curdent 06 khe wcr;ten-pulped and gnuund onu. AX on nem ;the AoQRec;trtic point on ZPC, ;the doubRe Raym about ;the minW-&den oil dnopR& i~ neduced in ;tkichnaa and the dn_opR& wU codace and continue to aggnegate into agglommaka . Invetmion dnom O/U ko W/O can UCCWL depending upon a nwnbm a 6 in;tmQeaked daotuh~. EReothokin&Lc inn&wnenta;t/iun to meanwre ;the ZPC, QReckProphonQkic mobilXty z&a pokeW and hakerning cuttrtent me invcduabte in ;the appficatiun ud emu-bion dRo;tat;iun ;to m&~c and nonm&~c minu.&. ] INTRODUCTION Recent interest in emulsion flotation can be ascribed to the necessity of selective separation and concentration of extremely fine minerals. That which follows is an elucidation of the many factors-in emulsion technology in application. In applied surface chemistry for solid-particulate separation and concentration, emulsion flotation is one of the intermediate processes between froth flotation, in which the continuous phase is water (99.5 to 99.999% by volume), and particulate extraction, in which the continuous phase is almost entirely an organic-fluid. Another intermediate process is particulate exchange (or partition) in which immiscible or very limitedly miscible phases are in controll¬ed but appreciable volumes. Surfactants are common to all of these

Jan 1, 1968

By James C. Bradbury

Tripoli is a naturally occurring, finely divided form of silica found chiefly in midwestern and southeastern states and used commercially in fillers and abrasives. The name comes from the location of a silica deposit in North Africa and was applied in the latter part of the 19th century to similar material near Seneca, Missouri. Subsequently, the North African material was found to be diatomite, composed of siliceous skeletons of microscopic marine plants called diatoms, and the material's name was changed to tripolite. The name, tripoli, remained with the Missouri silica, which is inorganic in origin, and tripoli is now used to designate all naturally occurring silica that is similar in characteristics and origin to the Missouri material. Just to confuse things further, in commercial trade tripoli usually designates silica from the Missouri-Oklahoma field, whereas silica from southern Illinois, the other major producing area, is called amorphous silica. Each term, however, may be used commercially for any material, regardless of place of origin that has the characteristics or uses ascribed to material from either major producing area. For example, Engineering and Mining Journal routinely lists under "tripoli," prices "f.o.b. Elco, I11." and "f.o.b. Seneca, Mo. and Rogers, Ark.", and under "silica, amorphous," prices "f.o.b. I11 and "f.o.b. Dierks, Ark." "Soft silica" is another term that has been applied to tripoli from Illinois, west central Arkansas, and Tennessee, presumably to distinguish it from the more compact Missouri material. It has also been used in the ceramic trade to distinguish tripoli from "hard" silica, or silica flour, which is produced by pulverizing silica sand. Tripoli is produced mainly in extreme southwestern Illinois, in the Missouri-Oklahoma district in Newton County, Missouri, and Ottawa County, Oklahoma; and in the novaculite belt of west central Arkansas. Some tripoli is produced for local and specialized uses near Austin, Texas.

Jan 1, 1980