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By Oscar H. Lentz

During 1960, the controversy over percentage depletion reached the level of debate between presidential candidates. Nixon took the position that he would not tamper with the status quo in this matter. Kennedy took the position that he was willing to take a fresh look at the issues involved. Kennedy's position appears to have been based upon two premises: (1) new sources of federal revenue may be needed; and (2) current depletion rates, even if sound in principle, may be too high and, therefore, inequitable. The latter premise constitutes the basis for the claims that depletion allowances are simply "loopholes" of tax avoidance. Very probably the controversy over percentage depletion will remain in the political limelight during most of the coming decade. It is quite possible that the current depletion rates, at least those for oil and gas, will be reduced during this period. The aim of this paper is to isolate the complex causes of this mounting opposition to percentage depletion.

Jan 1, 1961

By John W. Goth

This article, though not common feature material, should be of reader interest. Goth made this presentation as the keynote address at the 19th Annual Intermountain Minerals Conference in Vail, CO, in August. Introduction Working backward, what is an LDC? LDC stands for Less Developed Country. LDCs play a dynamic role in world supply and demand of basic materials. They occupy an equally important position in international marketing and finance. I will explain later some of my concerns with LDCs. First, I want to address an issue I think is of equal or even greater concern. Mining and High Technology Unfortunately, many people believe that America must make a decision now between being a smokestack-based economy or a high-technology-based economy. Some would have you believe that smokestack America is dead. Our only option is to turn to high technology, in a manner similar to countries such as Japan. Presumably, when we talk about high-technology industries we envision organizations that came into being within the last decade or so and incorporate microelectronics, biotechnology, and interconnected computers. The entire workforce is clad in lab coats and there are few employees in proportion to the work performed. High-technology industry is not labor-intensive work thanks to the efficient robots used. On the opposite side are smoke-stack industries, that we presume include the older, basic industries such as mining, agriculture, iron and steel manufacturing, ship-building, auto manufacturing, and nearly all forms of construction. These industries are judged to be labor intensive, requiring unsophisticated and untrained employees who succeed by the sweat of their brows rather than by advanced degrees in mathematics and physics. If these are indeed the presumptions about high technology versus smokestack industries, then I submit that those presumptions are a disaster. They are wrong and far from the truth. Smokestack industries, such as mining and the others mentioned, are indeed much older than some of the recently founded high-tech industries. But this does not mean that those smokestack industries are low-technology industries. On the contrary, American agricul¬ture is a very high-technology industry whose crop yields are the envy of the entire world. Mining uses virtually all of the advances available through modern technology. Far too many opinion leaders still envision mining as Humphrey Bogart and John Huston in the movie Treasure of the Sierra Madre. Yet there are many who hold the opinion that our basic industries are dead and that this country's future depends on specialized high-technology industries and services. That is tantamount to announcing we will continue to build space shuttle vehicles, but we no longer need launching pads and landing fields. The point is, we should not be wasting our time talking about "new" industries and "old" industries. We should devote our time and effort to industries that are effective and efficient in meeting our needs, in contrast to industries that are not effective and efficient in meeting our needs. Less Developed Countries That leads me to some of the problems I perceive with policies regarding the previously mentioned LDCs - Less Developed Countries. Far too many people do not realize that many of the smokestack industries being lauded in Less Developed Countries are being operated at a loss and to the detriment of worldwide industry. And the losses incurred

Jan 12, 1983

By D. C. McIntire

The Homer City Station, jointly owned by New York State Electric and Gas Corporation and Pennsylvania Electric Company is a three unit coal fired station. The first two units were put into commercial operation in 1969; the third unit became commercial in 1977. Units 1 and 2 are subject to the Pennsylvania State Implementation Plan (SIP) emission limit of 3.7 pounds of S02 per million BTU. Unit 3, having started construction later, is subject to the Clean Air Act, New Source Performance Standards emission levels of 1.2 pounds of 50-2 per million BTU.

Jan 1, 1988

The 86th Annual Meeting of the SME Minnesota section/74th Annual University of Minnesota Mining Symposium partnered with the Canadian Institute of Mining Metallurgy and Petroleum (CIM)?s Iron Ore Symposium for a historic joint conference, held this year in Duluth, MN, April 15- 17. One of a flurry of recent collaborations between SME and CIM, the joint conference was a natural fit for the conference held in the heart of the Iron Range. As CIM National President Terence Bowles said in his joint keynote with SME President Jessica Kogel, ?The U.S. imports $51 billion from Canada and Canada imports $38 billion the U.S.; that?s 50 percent of Canada?s exports and 51 percent of its imports.? The two countries? economies are linked, and nowhere more closely than in their iron ore mining activities. Kogel opened the conference with a plenary speech identifying the top 10 issues facing mining and how these issues present opportunities for mining companies. She said that it is important that the mining industry stay flexible and adapt to changing conditions, or it will go the way of the dinosaur. However, she said that these challenges can lead to new opportunities. For example, one of the major challenges facing mining is the current state of risk aversion among investors, which makes for ?less money in the pipeline.? However, this situation creates a better climate for mergers and acquisitions, which is another, less risky way to get funding. Likewise, another challenge globally is geopolitical risk; this challenge is likely to drive growth toward stable countries, which was good news for an audience composed mostly of Minnesota and Canadian mining industry personnel. One of the highlights of Kogel?s address was a triangle illustrating the interdependent nature of sustainable development and corporate social responsibility (Fig. 1). This triangle consists of four equal components: the social environment, transparency, local and global impact and future generations. The most important takeaway, Kogel said, was that sustainable development and environmental and social responsibility, while they do add to the cost of doing business, are no longer optional.

Aug 1, 2013

By Richard R. Klimpel

INTRODUCTION Froth flotation is the most widely used and economic means of concentrating metal sulfide ores such as those containing copper, lead, zinc, nickel, molybdenum, and pyrite. Also recoverable are other metal species that are often associated with sulfide ores such as cobalt, platinum, gold, silver, etc. Froth flotation is a physico-chemical process for separating finely ground minerals from their associated gangue material. The process involves chemical treatment of a finely divided (ground) ore in a water pulp to create conditions favorable for the attachment of certain of the mineral particles to air bubbles. The air bubbles then carry the selected minerals, called valuable, to the surface of the pulp to form a stabilized froth which is removed and recovered. The unattached gangue material remains submerged in the pulp and is either discarded or reprocessed. To obtain the adherence of the desired mineral particles to the air bubbles, at least two specific steps must occur: a hydrophobic (water hating) surface film must be formed on the particles to be floated along with a hydrophillic (water wetting) film on all other particles; and a controlled bubble surface tension interface must be maintained, allowing for high particlelbubble collision frequency and efficient attachment or sticking of the particle to the bubble once collision has taken place. In most flotation applications, the above two steps are controlled by chemical flotation reagents. The collector is a chemical reagent which produces the hydrophobic film on the valuable mineral particle and is the primary driving force that initiates the flotation process. The frother is a chemical reagent which influences the collision frequency and attachment efficiency of hydrophobic particles and air bubbles. Thousands of research papers and books have been published on the chemical theory behind sulfide mineral collectors, e.g., Fuerstenau (1962), Fuerstenau (1976), Fuerstenau, et. al. (1985), King (1982), Leja (1982) and Moudgil and Somasundaran (1987), This article will only address and summarize some of the more practical aspects of collector usage. The industrial scale practice of froth flotation in sulfide mineral concentration has changed little since the 1950's. For example, of the approximately 80,000 metric tons of sulfide mineral collectors used commercially (1980) in the free world, almost 98% were known and manufactured in some form 25 years ago. A very interesting and informative history of collector development has been given by Crozier (1984). In addition, the industrial scale practice of froth flotation applied to sulfide ores has proceeded since the 1920's with often little direct (predictive) scientific explanation due to the extreme complexity of the flotation process. Empirical testing has been a mainstay of industrial flotation reagent development and use. Even today there is often strong disagreement between researchers as to the mechanisms of chemical flotation practices that have been performed successfully at an industrial scale for many years. As a result of the above environment which makes reagent cost/performance analysis difficult for new reagents, there is a strong tendency for the flotation operation to use, and reagent companies to supply, as cheap as possible raw materials and manufactured products that are quite general in application. In the last 20 years or so, there has been increasing technical effort to tailor make reagents for specific applications, but to date such work has had little commercial impact. It is clearly the hope of this author and others that this situation will change in future years as technology improves and pressure for improved flotation performance intensifies. This article is a condensation of collector usage trends quantified as part of a comprehensive industrially oriented applications program on froth flotation organized by Klimpel and coworkers (1979-1987) and as reported in various countries that participated in the program from 1978-1983. No attempt will be made to provide specific.

Jan 1, 1986

By William Hustrulid

INTRODUCTION The Idarado mine lies high in the San Juan Moun¬tains on the divide between the Uncompahgre and San Miguel Rivers and consists of a consolidation of a number of old and prominent mining properties through which course some famous and very produc¬tive veins. Among the better known are the Smuggler, Tomboy, Montana-Argentine, Black Bear, Liberty Bell, Virginius, Flat, Barstow, and Japan, as well as many others. Most of these veins have been extensively mined over the past century and in the last three decades the Montana-Argentine and Black Bear veins have been the backbone of the Idarado mine; therefore, the descrip¬tion of the veins is limited to them. Access to the mine is through either the Treasury tunnel, whose portal is below Red Mountain Pass on US Highway 550 at an elevation of 3244 m (10,643 ft), or the Mill Level tunnel entrance 3.2 km (2 miles) east of Telluride, CO, at an elevation of 2761 m (9060 ft). The Treasury tunnel intersects the Black Bear vein 2643 m (8670 ft) from the portal and the Mill Level tunnel intersects the Argentine vein 2179 m (7150 ft) from the portal. Mining is by shrinkage stoping from slusher sublevels. The size of the scope blocks varies somewhat, but the standard size is 67 to 76 m (220 to 250 ft) long and 61 to 76 m (200 to 250 ft) high. The mine ranks either first or second in Colorado in yearly production of gold, silver, copper, lead, and zinc. It is 9.6 km (6 miles) from the Red Mountain plant to the Pandora plant, via interconnecting drifts and raises. There are engineering offices at both plants as a matter of convenience. The Red Mountain plant in¬cludes the company general offices, warehouse, carpen¬ter and machine shops, and mine change room. The Pandora plant consists of the mill and assay office, ma¬chine shops, and mine change room. The flotation mill has a capacity of 1632 t/d (1800 stpd), making a bul¬lion product and separate concentrates of lead, copper, and zinc. HISTORY OF THE MINE The Montana-Argentine vein was first extensively worked by the Tomboy Gold Mines Co., Ltd., a British concern. This company mined the stoped areas above the Ophir level between 1910 and the late 1920s and most of the stoped areas above the 2100 level between 1900 and the late 1920s. Gold was the principal ore metal mined. The area between the Revenue and Ophir levels was mined chiefly by the Revenue Mines Co. between 1900 and 1910. The ore was worked from the Revenue tun¬nel, which portals in Canyon Creek. Gold and silver were the chief metals recovered. The stopes between the 1700 and Revenue levels, as well as some higher stopes, were mined by Telluride Mines Inc. during the 1940s. The Mill Level tunnel was driven by that company from 1945 to 1948. Lead and zinc then became economically more important than the precious metals. In 1953, Idarado purchased Telluride Mines, which merged with the parent company in 1956. The Black Bear vein was first extensively worked by the Black Bear Mining Co. in the 1900s and by the Colorado Superior Mining Co. from about 1914 until snowslides at the mine camp [altitude 3750 m (12,300 ft)] terminated the company's operations in 1924. Leasers operated at intervals until 1934. The Treasury tunnel, formerly the Hammond tunnel, had been started before 1900 and reached the 1646-m (5400-ft) mark early in the 1900s, at which time activity lagged until the late 1930s. In the early 1940s, Idarado extended the Treasury tunnel from its heading at 1646 m (5400 ft) to the Black Bear vein and established a raise connec¬tion with the 600 level, the lowest level in the old mine. Since completion of initial work in the mid-1940s, systematic development of the mine, both in the driv¬ing of new headings and the utilization of older open¬ings, has resulted in the present extensive network of workings. GEOLOGY Introduction The oldest rocks of the area are the Precambrian metamorphic rocks, the Uncompahgre formation which are massive quartzites, some phyllites and slates, and dolomitic or limestone beds. West-dipping Paleozoic and Mesozoic strata lie on the Uncompahgre formation. These units are separated by a major angular uncomformity from overlying, essentially horizontal, Tertiary formations that include the basal Telluride conglomerate and several thousand feet of overlying volcanic rock. Intrusive rocks, mostly Tertiary in age, are common in the area, and are in the form of dikes, stocks, and sills. Dikes are very closely associated with some of the ore veins (Mayer). Description of Veins The Black Bear and Argentine veins range from 0.6 to 7.6 m (2 to 25 ft) in width, but in most places are 1.5 to 2 m (5 to 7 ft) wide. They vary in character from a well-defined tabular structure between sharp "frozen" walls, or gouge seams, to an irregular zone of quartz and quartz-sulfide stringers. Many gouge seams within the veins make the veins blocky and loose. Common gangue minerals in the veins include quartz, pyrite, rhodonite, chlorite, sericite, clay minerals, epidote, calcite, adularia, rhodocrosite, fluorite, and specularite. Quartz constitutes 60 to 70% of the veins and varies widely in character, ranging in color from clear through white, gray, and green, to amethyst. Chlorite, sericite, the clay minerals, and fine-grained quartz are common alteration products of the vein walls and of wall rock fragments in the veins. Epidote is an altera¬tion of the dike or, less commonly, of tuff-breccia. Calcite, adularia, fluorite, and rhodocrosite, which are wide¬

Jan 1, 1982

By J. A. Dos Santos

High angle conveyor (HAC®) systems in open pit mining offer many advantages over the traditional, truck only, haulage systems, including: (1) superior energy efficiency, (2) less dependency on petroleum products, (3) less sensitivity to inflation, (4) less labor, (5) less excavation for the amount of ore recovered, and (6) less ramp construction and maintenance costs. Previous studies had revealed the technical and economic feasibility of high angle conveyors. This paper presents the Sandwich Belt HAC® as the vital link to optimization of in-pit conveying systems. HAC development to date is discussed, beginning with studies in 1979, to the first large scale prototype in 1983, to the first commercial unit in 1984, into "the latest commercial installations. Discussion continues with the HAC systems to suit the various open pit mining operations and the corresponding characteristics of the system components, particularly the high angle conveyor. The range of HAC systems from the low capacity (up to 1,814 t/h), low lift (10.7 to 36.6M), highly mobile to the moderate capacity (1,814 to 3,629 t/h), moderate lift (36.6 to 76.2M), intermittently mobile to the high capacity (greater than 3,629 t/h), high lift (greater than 76.2M), semi-mobile, are discussed along with some possible combinations of these.

Jan 1, 1989

By H. G. Papacek

The Fabrica Mine of the Brazilian iron ore company Ferteco mines on an extremely inhomogenous ore deposit. A large amount of the crude ore consists of fines minus 100 micron which cannot be sold without further treatment because of its chemical and physical properties. In order to make full use of the mined crude ore an expansion program has been realized which incorporates among others a concentrator to produce classified blast furnace ore , sinter feed and pellet feed. The pellet feed is converted in a 2.5 million tons per year Lurgi Dravo plant into high grade pellets. The paper discusses the selection of the concentration process, the pelletizing process and describes the experiences with the operation plant during the startup and the first years of operation.

Jan 1, 1979

By T. W. Camm, J. C. Johnson, S. D. Rosenthal

"Most engineers are bright, hard-working, reliable and prefer to avoid conflict. An engineering curriculum tends to self-select these characteristics. By most standards, you would expect workers exhibiting these traits to require minimal supervision. But, is this true? Is this how most current engineering managers lead? Looking at some current theories on leadership combined with personal anecdotes, this article will look at some common misconceptions about leading engineers.Engineers are different. There, it has been said. From cartoons to movies to television shows and more, there is a reason stereotypes of engineers resonate. Yes, you can find a lot of individual variation among specific engineers that you may know, but they do not detract from some of the overarching commonalities that engineers are known for.Clash of culturesWhat distinguishes a professional? Raelin (1985), in his book Clash of Cultures, describes professionals as having superior intellectual training, maintaining their own standards of excellence and being supported by associations that maintain the quality of the profession. Engineers obviously fit all three of these ideas: an engineering degree is still regarded as one of the most difficult to attain. Standards are maintained both through peer review and in academia, through ABET accreditation and through professional associations like SME to promote the discipline and foster technical growth.Six characteristics representing professional status are described by Raelin (1985, p. 9):• Expertise — prolonged specialized training in a body of abstract knowledge.• Autonomy — the freedom to choose the means to solve a problem.• Commitment — primary interest is in pursuing the practice of one’s own chosen specialty.• Identification — identifying with the profession and with fellow professionals, both through formal associations and through peers external to the organization.• Ethics — providing service without concern for oneself or without becoming emotionally involved with the client.• Standards — committed to help in policing the conduct of fellow professionals."

Jan 1, 2018

By David J. Collins

The emergence of activated charcoal adsorption as the most popular recovery method for precious metals, has led to numerous innovations aimed at increasing the efficiency of the process. This article describes a change in traditional charcoal transfer methods which will aid in reducing charcoal attrition losses. Studies have shown that significant charcoal attrition takes place during transfer, be it when using airlifts or centrifugal pumps. Tests conducted at Pinson Mines indicated a 4 to 8% loss to the minus 20 mesh fraction of charcoal after three (3) hours of pumping charcoal. Tests conducted while the author was at Jerritt Canyon indicated that charcoal transfer was a major contributor to charcoal losses; a decrease in the amount of coarse charcoal (plus 12 mesh) and an increase in the amount of finer charcoal (minus 16 plus 20 mesh) was noted as charcoal was moved to the head of the adsorption circuit.

Jan 1, 1998

By J. D. Cooper, D. W. Thompson, J. Basiuk, W. Cass, R. Ilves

The Department of Thoracic Surgery and Pathology at the Toronto General Hospital have had a long standing interest in the early detection and treatment of carcinoma of the lung. Our initial experience was with a population at risk due to a prolonged period of cigarette smoking. More recently our efforts have turned to industrial exposure, specifically in the nickel and uranium industries. [Initial Screening Project] (1) For a three year period 1963 to 1966 a cytology screening program was carried out through the Out-Patient Department. The study was limited to cigarette smokers over 40 in age. A total of 1586 patients were examined. Of the sputa collected, the classification is seen in Table 1. There were 11 malignant sputa present. Added to this number were 25 patients with symptoms, normal chest X-rays, but malignant cells on cytology, and a further 5 patients in whom an abnormality (eventually proven non-malignant) showed on X-ray, and sputum showed malignancy which was radio logically occult. (Table II). This gave a total of 41 patients with malignant sputum who were evaluated between 1960 and 1966. The clinical course of these patients is seen in Table III. Only 19 of 41 patients had localization and treatment of their tumour during that study period and this low rate of localization attests to the technical difficulties endoscopy in that day presented. The method of localization was as follows: a) 6 patients showed an area of segmental pneumonitis somewhere in this time period b) Using the rigid bronchoscope localized the tumour in 9. This was proven by direct biopsy, and frequently required more than one bronchoscopy over a prolonged time period. c) bronchograms and tomograms showed abnormalities in 5 patients. Of these 19 patients, 5 were treated by radiotherapy because of general condition or refusal of surgery. Three of the irradiated patients died of recurrent cancer within three years. The other two died within one year of unrelated disease. Fourteen patients underwent resection, with one operative mortality. At pathology, the tumours were "in situ" in 6 and invasive in 13. There was no evidence of nodal spread. When last followed up in 1979, there were no cases of recurrent tumour and no cases of second lung primary tumours. Similar experiences have been reported from the Mayo Clinic (2), Johns Hopkins (3) and Memorial Hospitals (4). Early detection of radiologically occult tumours which are in situ or minimally invasive has given uniformly good results. There have been no deaths from recurrent or metastatic cancer in surgically resected patients, and only one second primary tumour has been detected. Interestingly, the Hopkins group reports that 5 patients with Stage I squamous cell tumours refused operation. One refused any treatment and died of disease at 12 months. Three were radiated, and were alive from 14-38 months post-treatment, all with evidence of recurrent disease. [Sudbury Sintering Plant Study](5) From 1948 to 1963 an open travelling-grate sintering process was employed to convert nickel sulfide to nickel oxide at an International Nickel Company operation. The environment in this plant was particularly dusty and filled with fumes. It became apparent by 1969 that the incidence of bronchogenic carcinoma was markedly increased in workers from this plant. A concerted effort was made to track down all workmen with this exposure. During 1973 and 1974, 268 men were studied. Chest radiographs were done and showed no mass lesions. Sputum was collected on three consecutive days and analyzed. There were 12 men with malignant sputum, all of the squamous cell variety. Two refused any investigation, one presenting 31/2 years later with extensive hronchogenic carcinoma, and the other 5 years later with extensive carcinoma of the maxillary sinus. In the remaining ten patients careful rhinolaryngeal examination as well as a detailed bronchoscopy, involving examination, brushings and biopsy of all pulmonary segments was carried out. One patient was found to have laryngeal carcinoma and was treated by radiation. In nine patients, the malignancy was localized to the lung, leading to six lobectomies, two pneumonectomies and one sleeve lobectomy at operation. However, the follow-up in these cases suggests a different biological behaviour with these industrially related tumours. While no tumour has recurred locally, one patient has died of metastatic cancer and two patients have developed second and one patient a third pulmonary primary cancer. However, survival has still been much better than wits radiographically manifest lung cancer. [Technique of Localization] (6) Following a careful rhinolaryngeal examina examined and then the lower respiratory tract is examined. This is all performed under general anaesthesia. The trachea is examined with the rigid Jackson bronchoscope, collect-

Jan 1, 1981

By E. K. C. Chanda

The best use of available reserves to give good metal recoveries relies on short term mine production scheduling.-The aim is usually to produce a plan to guide mining in specific areas that will enable mine operations to deliver the budgeted tonnes and grade to the mill and keep within the long range mine plan. Thus, short term production scheduling is an important aspect of the open pit mine planning function. Since the 60's increased attention has been paid to effective production scheduling as a means of improving the economic viability of existing mines. Hence, mine scheduling scheduling systems have been evolving rapidly during the last two decades. These systems include manual techniques, computer based simulation, mathematical programming and more recently Computer Aided Design (CAD). Some general drawbacks of the current scheduling systems are that firstly, the costs of acquiring and using them are not at all insignificant especially for small to medium sized pits. Secondly, there is an inherent trial-and-error aspect in these systems. Thirdly, they tend to be suited for specific orebody geometries, hence lacking the necessary generality. For instance, the use of computer programs for planning open pits to mine stratiform orebodies raises problems which are not usually met when massive orebodies are considered. There for, a need exists to develop simpler but effective short term pit scheduling procedures suitable for stratiform type orebodies, considering their geometry and geology. This paper describes a PC- based model designed to assist the planning engineer in optimizing the short term production schedule in open pit mines with stratiform orebodies. The model is based on a combination of linear goal programming and deterministic mining simulation. The orebody model is made up of ore and waste mining regions where winning and and/or stripping are taking place. These shovel regions form the basic planning elements in the model. This approach does not require the laborious preparation and use of a regular block model. The computer program consists of main modules: (i) Data capture - processes the raw data into the required format for mine planning. (ii) Precedence mining constraints - checks the status of each shovel .region at the beginning of a given scheduling period with regard to geometrical mining constraints such as undercutting. (ii) LP- Optimization - provides an optimal selection of ore shovel regions which do not violet geometrical constraints for mining in the period, the objective, being to maximize the contained metal equivalent in the blended R-O-M ore and at the same time to minimize deviations in grade and tonnage from the call values. (iv) Post LP-Simulation - enables the user to smooth out the LP solution in order to adjust it to a practically executable plan and simulates mining of ore and waste for the period. Shovel allocation to selected ore and waste shovel regions, unit operations and depletion of reserves are executed in this module. Preliminary testing of the model for monthly production scheduling using data from Nchanga OPen Pit on the Zambian Copperbelt indicates that it can be a useful planning tool and gives acceptable results.

Jan 1, 1992

By M. Moss Stanley, Ronald P. Klepper

The objective of this chapter is to provide data that will assist in the selection and sizing of equipment utilized in the filtration method of separating solids from liquids. It should be recognized at the outset that in some situations more than one option may be available to achieve the target desired. In some cases purely technical objectives may be sacrificed because of cost considerations, design factors or other elements in order to satisfy optimization within the flowsheet and/or to provide bottom line results. Before considering available options, and prior to the next step of sizing out the selection, the operating criteria should be set down. The test work to develop selection and sizing data will be based on this data and the final products desired. This will help to establish initial parameters. A. GENERAL DATA 1. Material to be filtered: a. Solids b. Mother liquor 2. Feed rate of slurry in GPM 3. Density of slurry: Sp. Gr. Solids 4. Slurry: Temp. pH Viscosity 5. Source and method of feed 6. Valuable product: Solids Filtrate Both 7. Details on: Volatility Toxicity Stability 8. If flocculant is indicated, what has been used? 9. Describe product: (i.e., fibrous, cor 10. rosive, abrasive, inflammable, explosive, pasty, 11. Does product alter or require special environment during transport? 12. What type of filter media has been used successfully? 13. Is there any objection to use of a filter aid? If not, is there any preference? B. SOLIDS DATA 1. Sp. Gr. Bulk density 2. Screen analysis 3. Desired percentage moisture in cake 4. Solubility (state conditions): In mother liquor In wash water 5. Description of cake: (i.e., amorphous, fibrous, crystalline, colloidal, gran¬ular, thixotropic, 6. Special requirements for moisture de¬termination? 7. Can solids be compressed during dewatering? 8. Proposed product handling 9. Subsequent thermal drying or other pro¬cedure C. FILTRATE 1. Is separation of wash water and mother liquor desirable?

Jan 1, 1986

By K. S. Venkataraman

The physical properties of clay-water systems depend on the complicated system of forces between the clay particles themselves, and between the clay particles and the ions in the liquid phase. The kind and distribution of ions in, on, and between the clay particles and the size and the shape of the particles are the basic factors determining the macroscopic behavior of clay-water systems. Understanding the system requires a knowledge of the nature of the clay particles, their size, structure, composition, and surface properties, and of the manner in which they interact with ions [and molecules] in the surrounding liquid [or other medium]. The validity of Professor Brindley's words (Brindley, 1958), written three decades ago in the context of making pottery, whitewares, and electrical porcelains, transcends time, and the basic message is perhaps all the more important in the considerably expanded use of ceramics for structural, thermal, tribological, electronic, and other applications. Silicon carbide, silicon nitride, and sialons have been studied in the last two decades for high- temperature structural and tribological applications, particularly for using in internal combustion engines. Titanates, zirconates and niobates of barium, strontium and lead, have high dielectric constants, and are extensively used in the formulations for making capacitors. Hexagonal ferrites (molecular formula MO.6Fe2O3) are in use for making permanent magnets for fabricating miniature motors, and for assembling loud speakers, particle accelerators etc. Cubic ferrites such as magnesium-zinc ferrite and nickel-zinc ferrite are used as transformer cores, and for other high-frequency applications. In this context, Richerson's recent book (Richerson, 1984) on the general scope of traditional and technical ceramics is a good starting point for an overview of contemporary ceramics technology. Glasses are a whole class of amorphous materials used widely as sintering aids, and for making glass-bonded ceramics and glass-ceramic composites. Composites are yet another burgeoning field where two or more particulate components are used for improving the performance of ceramics. For all these applications, the inorganic starting materials are almost always submicron and near-micron powders. Understanding the powders' physicochemical properties, and their surface chemical interactions with the surrounding liquid/gaseous medium is-necessary for making reliable ceramic parts at competitive prices. Even though ceramics science and engineering has attained its separate identity in universities and the industry, ceramists themselves would concede that ceramics science is a cross-disciplinary field, having incorporated and assimilated within itself many principles from several apparently disjointed disciplines. Principles of material science, graduate-level physics and chemistry, polymer science, surface and colloid chemistry, transport phenomena, particle technology, unit operations commonly used in chemical engineering and mineral processing, and statistics and applied mathematics are integral part of any ceramics curriculum in universities. Added to this is the fact that all bench-scale successes in making ceramic parts are to be scaled-up for larger throughput operations. Understanding and applying process engineering principles of comminution, classification, drying, calcination, etc. then becomes essential. CERAMIC FORMING: Despite the diversity of the materials and processes, conceptually, the steps involved in making ceramic parts have remained the same over several decades: The different components for making the pan (usually one or more powders plus other forming and sintering additives) are proportioned and mixed thoroughly, and the well-mixed formulations are consolidated into desirable shapes known as "green bodies." Usually binders such as wax, clay, organic polymers and surfactants, whether dispersed or dissolved in a suitable liquid are used during mixing the batch for giving strength for the green bodies. In the dried green state, the inorganic powders typically occupy only 55 to 60% of the bulk volume of the body, depending on the particle size distributions of the powders and the forming history, with mostly inter- particle voids accounting for the rest of the void volume. SINTERING: The formed bodies are then fired in high- temperatures kilns/furnaces during which the parts are exposed to a predetermined temperature profile, and "soaked" for a certain duration at the final high temperatures, typically between 1200 K and 1900 K, and then cooled to room temperature. The gaseous atmosphere in the furnace is controlled (oxidizing, reducing, or inert) when necessary. During the initial stages of firing, volatile liquids evaporate, and during the intermediate temperatures between 400 and 600 K, the the organic polymeric additives pyrolize and oxidize into water vapor, CO, C02, and other gases. At still high temperature, the glasses, when present, soften, and simultaneously, the ceramic particles rearrange into a network of grains with definite grain boundaries so as to reduce the total interfacial free

Jan 1, 1990

By William Gleason

"During the past nine years the number of cellular phones connected to a network has increased from 34 percent of the world’s population in 2005 to 93 percent in 2014. These phones are powered by a combination of materials including elements such as gold, silver, copper and rare earths. And, as more parts of the world become connected to networks, the number of phones being produced, and the elements they will need, will continue to increase. The demand comes as prices for these commodities are slumping and access to the commodities is getting more difficult, technically and socially.These mobile devices have connected people around the world in ways that could not have been imagined two decades before, and, ironically, this communication has strengthened opposition to the development of the mines that produce the very materials they need to operate.In his keynote address to the 2014 SME Arizona Conference at the JW Starr Pass Resort in Tucson, AZ, on Dec. 8, 2014, John O. Marsden, SME President and president of Metallurgium, spoke to more than 500 attendees about the challenge to produce the materials that society needs while at the same time challenging the general public’s perception of mining that is often inaccurate and less than favorable.Marsden highlighted the amount of raw materials that will be needed not just for phones, but also for things such as automobiles, including electric cars, as a way to illustrate the importance of mining. Even so-called green products such as Tesla cars, which require about 317 kg (700 lbs) of aluminum, 13 kg (30 lbs) of copper and 36 kg (80 lbs) of cobalt for their eco-friendly batteries, will need materials mining provides.These are some of the numbers that the general public is often unaware of. They are part of the necessary things that mining provides for society but are rarely reported on. Instead, it is the accidents like the tailings spill at the Mount Polley Mine in British Columbia and at the Buena Vista Mine (Sonora, Mexico) that grab headlines and stick in the minds of the public, adding more challenges to an industry that already has its own complex technical challenges to deal with."

Jan 1, 2014

By E. F. Schnitzer, C. Lidstone, D. Cramer, P. J. Wampler

The River Island mining site is located at approximately river mile (RM) 15 on the Clackamas River, a large gravel-bed river in northwest Oregon. During major flooding in February 1996, rapid channel change occurred. The natural process of meander cutoff, slowed for several years by dike construction, was accelerated by erosion into gravel extraction ponds on the inside of a meander bend during the flood. In a matter of hours, the river cut off a meander and began flowing through a series of gravel pits located on the inside of the meander bend. The cutoff resulted in a reduction in reach length of approximately 1,100 m. Erosion by bed lowering, knick point retreat and lateral erosion of upstream river banks occurred quickly. Within two days of the peak flow, 3.5 hectares of land and 105,500 m3 of gravel were eroded from the river bank just above the cutoff location. Much of this gravel moved a short distance downstream into the excavation. Reach slope increased from 0.0022 to approximately 0.0035 in the cutoff reach. Between 1996 and 2003, the knick point from the meander cutoff has migrated 2,290 m upstream, resulting in increased bed load transport, incision, and local lowering of the water table. In 1993, prior to the meander cutoff, transects were surveyed in the River Island reach upstream of the cutoff location. Resurvey of these transects and aerial photo analysis indicates that 96% of the knick point migration occurred during the first winter following meander cutoff. Connection of the flowing river to the off-channel ponds has had minimal effect on water temperatures in the mainstem Clackamas River. It is likely that this minimal change in temperature will decrease as ponds are isolated from active river flow by gravel bar deposition. Fish net-ting in spring 2002, suggests that salmonid use of the pond in the spring is minimal. The most abundant native species netted were large-scale sucker and northern pikeminnow. The most abundant non-native species netted was brown bullhead. Early regulation by state and federal agencies did not adequately evaluate potential impacts to the river and the floodplain; nor did it evaluate future impacts related to geomorphic processes and sediment transport. New permit evaluation methods, currently implemented by both Oregon and Washington, incorporate 1) river dynamism through historic river migration analysis; 2) stability of human structures in light of river dynamics; and 3) sediment transport and its impact on channel stability and dynamics. The gravel pit capture at River Island highlights the potential risks of mining in an active secondary channel of a large gravel-bed river. Mining deeper than the depth of the adjacent channel, within the active migration zone, may increase off-site impacts. In locations where multiple gravel excavations are present within the meander zone, a comprehensive reclamation and restoration plan should be developed which provides long-term channel stability within the natural variability of the entire river reach.

Jan 1, 2006

By Paul D. Tomlingson

Numerous worthwhile benefits accrue to the industrial organization that is supported by a maintenance organization performing at a world class level. That organization will be favored with consistently reliable production equipment. It will be assured of meeting production goals. Its product will exceed marketplace standards. Its customers will see them as a quality organization. Its employees will enjoy job satisfaction and the plant will realize continuing profitability. Every industrial plant aspires to achieve ?world class? status knowing it can compete favorably with the best, most profitable organizations in the world. The trick is to achieve the attributes that qualify your organization for world class status. But there are no world class maintenance organizations. Rather, there are world class industrial organizations that include a world class maintenance organization. Maintenance, by itself, is a service provider, dependent on the support and cooperation of other departments. When that service is exceptional, it is made that way because maintenance is operating in a plant environment that requires it to be exceptional. Managers have created an environment in which maintenance can be exceptional. The plant, mine or facility manager must acknowledge from the start that maintenance is not a stand-alone effort of a plant maintenance department. It will require the joint efforts of all plant departments. Quality material support and full cooperation from operations, for example, are among the essential requisites for effective maintenance and achievement of world class maintenance status. When attributes such as these are reinforced by dedicated plant managers, profitability soon follows.

By Randall J. Weege

Nickel laterites throughout the world are similar in their gross aspects, but vary significantly in detail. The deposits occur in two separate and distinct geologic settings --those formed over ultramafic rocks which were mechanically emplaced, and those formed over ultramafic rocks that were intruded as melts. The source of the primary nickel in the parent rock may occur both as ionic replacement in silicate lattices and as nickel sulfides. Factors controlling the degree of laterization and nickel enrichment are dependent upon the parent rock characteristics as well as chemical and climatic conditions. Two chemically and physically distinct zones (oxide and saprolite) are commonly present in the laterized rock, but one or the other may be extremely thin or absent. Cobalt and copper may be present in recoverable amounts. Geologic, geophysical and geochemical methods are all utilized in exploring for these deposits. These methods are compared, evaluated and illustrated in the paper. Drilling patterns and ore reserve calculations are also discussed. In contrast to many ore deposits, processing costs are much higher than mining costs. The most efficient processing method is directly dependent upon the chemical composition of the ore. This variation in the chemical and physical characteristics of nickel laterites requires a detailed test program of the metallurgical response to representative samples and blends of ore. Detailed laboratory and bench-scale metallurgical tests are necessary prior to a full scale pilot plant test.

Jan 1, 1978

By Ed Sullivan

"Australia is one of the richest continents when it comes to mineral extraction, ranging from exotic projects like the Olympic Dam — a copper, silver and uranium mine believed to have the world’s largest uranium resource — to the extensive iron ore, nickel, coal and gemstone formations that provide many of the country’s most rewarding exports.Among the challenges to succeed in this industry is the ability to provide efficient “pitto- port” infrastructure performance, which essentially means ensuring that minerals move seamlessly from the point of extraction to the facilities that can then move them to international market destinations.To provide such efficiencies, avoid human error and facilitate automated mining functions, producers are increasingly turning to fiber optic cable suppliers for “end-to-end” communications and control solutions. Many such solutions include ruggedized cable and connectors that ensure the survival of fiber-based DCS/PLC automation/ control architectures for various types of mining operations, even in the harshest environments.Integrating the solutionAs industrial Ethernet and fiber optic cable emerges as the medium of choice in many industrial arenas, communication and control integration using the most appropriate products for a specific application is increasingly important.“This whole ‘pit-to-port’ performance concept is focused on control and process automation,” says Boyd McDonald, Founder and Managing Director at Datalek Systems & Electrical, Rockhampton Area, Australia. “It also means bringing reliability to networks and providing the needed bandwidth. An appropriate plug-and-play solution is also important because it takes human error out of the equation.”Datalek Systems & Electrical, is responsible for the design, installation and maintenance of numerous fiber optic communications systems including those that involve automation, security, access control an CCTV systems for open-pit and underground mining operations as well as LNG and coal seam gas facilities."

Jan 1, 2015

By G. J. Simandl

Jade is a commercial term encompassing green, white, black or yellow-brown jadeitite and nephrite. Jadeitite consists of Na-rich pyroxene, whereas nephrite consists of prismatic to acicular amphiboles of the tremolite-actinolite series forming bundles that are randomly oriented and interlocked. Nephrite is tougher (harder to break) than jadeitite. Its fracture strength is about 200 MN/m2 whereas that of jadeitite is about 100 MN/m2. On the other hand, jadeitite has a higher hardness (7 compared to 6.5 on the Mohs scale). There are over fifty known nephrite occurrences in British Columbia (B.C.). These occurrences consist of individual blocks, boulder fields, talus blocks and in situ occurrences. Most of the in situ occurrences are lens or cigar shaped. They occur at, or near the contact of ultramafic/mafic rocks (mainly serpentinites) with cherts, and other metasedimentary or igneous felsic rocks of Mississippian to Jurassic oceanic terranes such as Cache Creek and Slide Mountain. These contacts are commonly interpreted as shear/fault related. In general, it is believed that the B.C. nephrite formed by metasomatic exchange between ultramafic and silica-bearing rocks. Impurities in B.C. nephrite are spinel group minerals (chromite, magnetite, picolite), diopside, uvarovite, titanite, chlorite, and talc. Jadeitite is slightly denser than nephrite and good quality material sinks in methyl iodine. There are no known jadeitite occurrences of economic interest in B.C., but there are at least four geographic areas where favorable lithologies, and metamorphic conditions (Pn) required for the formation of jadeitite coincide. These are Bridge River, Pinchi Lake, Dease Lake, and Jennings River. These areas are known to contain small concentrations of jadeite, or are characterized by blueschist or eclogite-grade metamorphic conditions. Rhodonite and pyroxmangite are MnSi03 polymorphs. These minerals are pyroxenoids and are macroscopically and microscopically very similar. For brevity, both are grouped together under the term "rhodonite". Most of the B.C. occurrences are hosted by late Paleozoic chert sequences and are lens shaped and concordant. The common association of rhodonite with iron formations, jasperoids, and/or volcanogenic sulphide deposits in southwestern B.C. permits the delineation of favorable horizons using magnetic or electro-magnetic geophysical methods. Geographic associations between manganese showings and sulphide deposits, and the hydrothermal chemical signature of the rhodonite occurrences from this area, suggest a genetic link between rhodonite and volcanogenic sulphide deposits. The typical rhodonite rocks consist of rhodonite, pyroxmangite, neotocite, black amorphous Mn-oxides, Mn-bearing garnet, ± epidote, ±chlorite, ±rhodochrosite, ± parakutnah-orite, ± Mn-bearing calcite, ± iron oxides and hydroxides. Garnet ± epidote forms yellow patches and layers within the rhodonite. Within some of the rhodonite occurrences, the garnet is altered to chlorite. Rhodonite-bearing rock is commonly cross cut by secondary manganese oxide veins, creating a characteristic web-like texture. In several localities, the contorted bedding planes are readily recognized. Mn-calcite and quartz also crosscut rhodonite. Rhodonite deposits hosted by high grade metamorphic rocks may contain pyroxmangite. Rhodonite is an important gemstone and ornamental stone in B.C., second only to nephrite in dollar value. B.C. nephrite and rhodonite have been used for the past 100 years in local jewelry and ornamental applications. More recently they have been used in table tops, and they have potential as upscale materials in tile-making. There may be a market for tiles made from lower grade materials that were previously extracted and stockpiled. The prices of nephrite, jadeitite, and rhodonite vary widely with quality, but gem and ornamental grade stones are relatively highly priced materials and they trade world-wide.

Jan 1, 2001