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By Ross W. Smith, Salim Akhtar

Flotation of oxide minerals, particularly silicates, with cationic collectors differs substantially from classic flotation of sulfide minerals using sulfhydryl collectors. In the case of cationic flotation of these minerals, in general: 1. There is a greater importance of electrostatic interaction between mineral and collector. 2. Longer-chained collectors are required; as a rule at least 10 carbons must be present in the hydrocarbon chain. 3. Moderate concentration of collector is required. 4. Attachment between collector and mineral appears to be less strong even though the system may exhibit a large contact angle. 5. Required conditioning time before flotation is usually relatively short. 6. There is sensitivity to slimes. 7. The collectors usually possess frothing power. 8. Selectivity of cationic collectors for specific minerals is usually poor. Almost any of the oxide and silicate minerals may be floated using cationic collectors. However, specific response to these collect- ors varies with mineral type. The following classes and minerals are

Jan 1, 1976

By Jack S. Watson, Rasika Nimkar, Robert M. Counce, BRADLEY BENNETT, Patrick Zhang

The purpose of this work is to develop a conceptual recovery process for thorium dioxide (ThO2) from its primary source, monazite. The study-level design presented in this paper represents an economically viable method for conducting ThO2 extraction from monazite ore while also recovering byproducts that include P2O5 and other rare earth element oxides rather than producing unnecessary waste streams. Three key points to note in the development of this process design are: (1) the process economics relied heavily on recovery of rare earth byproducts, (2) the thorium handling portions of the process could effectively be segregated from the rare earth and phosphate handling portions of the process, and (3) the thorium and uranium content in waste streams should be carefully managed and eliminated where possible.

By T. W. Healy, M. S. Moignard

The use of electrokinetic or zeta-potential phenomena in studies of the properties of mineral sulphides has increased greatly over recent years. This review aims to examine and discuss the body of literature on the subject of electrokinetic properties of sulphides in a comprehensive and critical manner. Although the review covers the period from 1925 to 1975, it is only in the past ten years that researchers have been fully aware of the implications and problems of chemical reactions, notably oxidation and precipitation reactions, on the surface properties of sulphide minerals. These papers are discussed in more detail than the earlier publications. A table containing a list of determinations of iso-electric- points and points-of-zero-charge of mineral sulphides, and the methods employed in obtaining these results, is presented.

Jan 1, 1976

By Ora H. Rostad

The sequence of events preceeding the discovery of the Mount Emmons molybdenite include some inadvertent near misses by several groups. The events are given in general chronological order to bring out the essentially contemporaneous, but different activities by several groups in two areas on opposite sides of Mount Emmons. The Mount Emmons molybdenite deposit lies in the Elk Mountain mining district. The west edge of the deposit is near the boundary between the Elk Mountain and Ruby mining districts as shown by the USGS map included (see Fig. 1). Considerable history regarding the Keystone silver-lead-zinc mine is given because of its proximity to the Mount Emmons molybdenite deposit which is on the other side of the mountain from Redwell Basin and where other significant activities took place. It should be noted that there was no documentary evidence available to me that would indicate that molybdenite was recognized to be present on, or under, any part of Mount Emmons, including Redwell Basin, before 1970. Veins containing silver-lead-zinc minerals were discovered in the Elk Mountain and Ruby mining districts about 1872. Some discoveries on the south flank of Mount Emmons about 1880 were developed into the Keystone mine. The Keystone has the largest cumulative production of metal ores of any of the mines in these districts. Most of the 413 Mt (455,473 st) of ore produced from the Keystone mine through August 1967 was produced after 1950. The ore averaged 175.4 gt (5.64 oz per ton) Ag, 2.62% Pb, 5.56% Zn, and 0.72% Cu.

Jan 1, 1991

By C. McLean, S. G. Kolb, A. J. Erickson, S. C. Moore

The Grossschloppen vein-uranium deposit, Bavaria, West Germany, was examined with underground workings during 1980-82 by Esso Erz GmbH, an affiliate of Exxon Minerals Company (EMC). Geologic evaluation entailed dense drilling of a portion of the deposit from workings constructed specifically for the program. Discovered in 1977, the deposit was initially explored by surface diamond drillholes which allowed definition of a 30-60 m wide vein system discontinuously mineralized along a 1000 m strike length and to at least a 450 m depth. The underground program was conceived as a cost-effective procedure to answer questions on vein correlation, grade continuity and variability. A 1200 m decline allowed access for detailed sampling of approximately 10% of the known area of mineralization. Fanned drillholes, logged by gamma probe, were spaced to provide intersections of veins at 10 to 20 m intervals. Six cross-cuts also penetrate the pitchblende and uranophane mineralization which occurs in 0.1 to 2.5 m thick quartz veins. Detailed cross-sections and level plans were constructed for resource estimates of the intensively studied portion of the vein system. The program resulted in the discovery of local, high grade areas and an average grade in the evaluated area nearly double that expected from surface drilling.

Jan 1, 1992

By I. E. Odom

The physiochemical properties and industrial uses of the clay mineral montmorillonite are reviewed. Montmorillonite is the most abundant species of the smectite clay mineral group and is the predominant mineral composing bentonite deposits. The crystal structure, chemical composition, exchangeable ion type, and small crystal size are responsible for several unique properties, including a large chemically active surface area, a high cation exchange capacity, and interlamellar surfaces having unusual hydration characteristics. The type of exchangeable ion, sodium (Na), calcium (Ca), and/or magnesium (Mg), has a major influence on industrial and chemical uses of montmorillonite because of their hydration characteristics. Natural occurrences of Na mont¬morillonite in commercial quantities are geographically limited, but Ca-Mg montmorillonite deposits are known worldwide. Foundry, well drilling, pelletizing, and civil engineering constitute the major uses of montmorillonite, but the total array of uses exceeds that of any other mineral.

Jan 1, 1988

By Arafat Ghosheh, Yousuf Abu-Rish, Darwish Amara, Mohammed Baderkhan

The Jordan Phosphate Mines Company is one of the world's major phosphate rock and phosphatic fertilizers producers (the second largest phosphate rock exporter), with ore reserves exceeding 2 billion tonnes, mainly located in the Eshidiya area. The Eshidiya phosphate deposits, 120 km north-east of Aqaba, are of sedimentary origin (as are all phosphate ore in Jordan). Three exploitable beds (Al, A2, and A3) with variable content of P205, CaO, SiO2, etc., are processed in order to produce 68-70,73-75, and 75-77% TCP grades. The A3 bed, which is characterized as the most siliceous containing 40-48% TCP, requires physical beneficiation using wet scrubbing, screening, and desliming by hydrocylone, followed by anionic conventional flotation to achieve 75- 77% TCP grade. For the last 15 years extensive laboratory and pilot tests (including physical, chemical, and mineralogical studies) were carried out. After operating the industrial plant, certain modifications were deemed necessary to adjust the operational parameters and the final flowsheet, which was followed to obtain the targeted quantity and quality of concentrate.

Jan 1, 1999

By M. J. McPherson, P. Mousset-Jones, G. Danko, F. Calizaya, K. You

The friction factor is one of the more difficult parameters to determine in ventilation planning. In practice, this can be estimated from published factors such as those of McElroy. The problem with this approach is that the selection requires some judgement, and the estimated values offer no more than guideline accuracy. This study, examines the effects of four factors on the coefficient of friction for a simulated mine airway. The factors are: airway cross-section, asperity height, flow direction, and cross-cut spacing. The study includes the modeling of a mine airway and the evaluation of the results from 13 experiments on flows of air over rough surfaces. The model, physically represented by a wind tunnel, includes a rough surface section which can be modified to simulate mine airways of various shape and asperity height. Most of the experiments were performed under controlled flow conditions during which the Reynolds number was varied between 50,000 and 300,0000. Based on this study, the friction factor for a mine opening was found to depend not only on the size and shape of the surface asperities but is also affected by the orientation of them in relation to the flow direction.

Jan 1, 1991

By Deborah A. Kramer

Although beryllium was initially discovered in 1797, it was not until 1916 that the first significant quantity of beryllium metal ingot was produced in the United States. Before 1940, most of the small quantity of beryllium metal used in the United States was supplied by Germany. Beryllium was not used in its metallic form; it was used as an alloying addition to other metals, mainly copper and nickel. World consumption of beryllium at that time was estimated to be a few hundred kilograms annually. Because of increased tensions in Europe before World War II, imports of metal from Germany ceased in 1940, and domestic production was required to meet the needs of the military. As a result, by 1946, the United States became the principal supplier of beryllium products for the world, a condition that prevails today. Because of beryllium's high strength, light weight, and high thermal conductivity, it has been used in a large number of industrial and defense applications as a metal, alloy, and oxide. The United States is the only country other than China and the former USSR currently producing beryllium products from beryllium ores and concentrates. Bertrandite, mined in Utah, is the principal ore source of domestically produced products. Imported ore, mainly from Brazil, supplements domestic ore supplies. Production and consumption data for the United States is shown in [Figs. 1 and 2]. Production data for 1969-1979 is withheld to avoid disclosing company proprietary data.

Jan 1, 1994

By G. J. Olson, K. S. Noah

A combined physical/biochemical process for the precombustion removal of 13 inorganic hazardous air pollutant (HAP) precursors, i.e., Sb, As, Be, Cd, Cr, Cl, Co, F, Pb, Hg, Mn, Ni and Se, from coal was tested. Biochemical processes for removal of HAP precursors from coal potentially offer advantages of deeper cleaning, more specificity and less coal loss. The slurry column is a second-generation process for the beneficiation o f fine (60-mesh x µm coal by a combination of physical separation of mineral matter and biooxidation of pyrite. Sixty-seven percent removal of pyrite from a 60-mesh Pittsburgh #8 coal was achieved at a 35% (w/w) slurry concentration and a five-day reactor residence time. Ninety percent of the heating value of the feed coal was recovered. Among the HAP precursors of most concern, over half of the Se, As and Hg were removed from the feed coal. From 40% to 70% of most HAP precursors were removed from the feed coal. Hg in the feed coal was reduced from 0.12 to 0.054 ,µg/g in the product coal, while waste coal contained 0.24 µg/g.

Jan 1, 2000

By J. L. González-Chávez, A. Ballester, M. L. Blázquez, F. González

In recent years, the bioleaching of sulfidic raw materials has been of great interest. However, the application of this biotechnology is now very limited for many different complex reasons. The mechanism of the chemical and electrochemical reactions taking part in the process is not well understood. The application of electrochemical techniques is useful in its elucidation. Among the common sulfides, galena has been studied very little with respect to its behavior during bioleaching. Therefore, the electrochemical evolution of massive electrodes of lead sulfide in the presence and absence of' a mixed culture of mesophilic microorganisms was investi¬gated by the application of potentiometry, anodic and ca¬thodic polarization and cyclic voltammetry. The agitation rate, the use of pH control and the composition of the nutrient mediums did not have any significant affects on the oxidation of galena. However, the temperature (25 'to 45 °C), the scan rate (4 to 100 mV/s) and the acid used to adjust the pH were significant variables that influenced sulfide oxidation. There¬fore, the peak (600 to 1,000 mV) corresponding to the oxida¬tion of sulfide ions from the mineral was only detected in the presence of a complexing anion of lead. In the presence of bacteria, the peaks corresponding to galena oxidation de¬creased and, at the same time, new peaks appeared both during the oxidation at -300 mV and during the reduction of the mineral surface at 150 and -300 mV. These signals were more important when the attack time increased. The rest potential of bioleached mineral increased with an increase in leaching time, which was related to the electrochemical transformation of the galena surface.

Jan 1, 2000

By Murray D. Lester

The relationship between bauxite and energy has two distinct aspects. On the one hand, since virtually all of the bauxite that is mined winds up as aluminum metal, the economic health and future of the bauxite industry and of the bauxite-producing countries depend on the continuing vigour and competitiveness of aluminum against alternative metals and materials. The price of aluminum is, in turn, particularly dependent on the price of energy. Hence, the need for bauxite is ultimately affected by the price of energy. The second aspect relates to location of the bauxite industry. There is no shortage of bauxite resources in the world. For various reasons, as we shall see, there is a growing tendency toward the integration of bauxite mining, bauxite refining and aluminum smelting in those countries that have the resources both of bauxite and of energy necessary to support the entire production chain. Thus, the availability of attractive energy supplies will increasingly favour development of bauxite mining: the traditional export of bauxite as a simple raw material is likely to diminish in relative terms. In short, both the amount of bauxite mined and where this mining will take place are related to energy considerations. Let us first have a brief look at the four basic activities that are involved in our integrated operations: A. The bauxite is mined and moved to an ore plant. This step does not require more than relatively modest amounts of energy normally associated with excavation, loading and shipping of any bulk material. We need about four or five tonnes of bauxite for every tonne of metal produced.

Jan 1, 1984

By Alan Bye

Sandsloot open pit is situated on the northern limb of the Bushveld Complex, 250 km north east of Johannesburg, South Africa. Sandsloot is currently the largest open pit platinum mine in the world and is one of six potential open pits in the area. The geotechnical strength properties of the Platreef have posed significant mining and processing challenges to the PPRust operation since inception in 1992. In order to optimise the whole business as opposed to isolated cost centres a mine to mill initiative was embarked upon in 1997. Initial work focussed on ore characterisation and an entire suite of data was collected for each rock type. This included mineralogy, geochemistry, geotechnical, blastability indices as well as metallurgical strength data. The second phase involved the clear definition of customer requirements, namely the optimum performance criteria for the plant and mining departments. This involved extensive field trials and data capture to measure the interaction and influence of the mine to mill value chain. Once the design targets were defined a 3D geotechnical model was constructed to ensure that the targets were consistently achieved. The model is very similar to an ore reserve model however it is populated with geotechnical, metallurgical and blast index data. Through software queries the appropriate blast powder factor for each mining block can be obtained thereby ensuring the correct fragmentation is blasted for the plant and mining operation. The initiative has delivered significant results showing improvements across the mine to mill value chain. These include increased loading rates, reduced electricity and crushing consumables as well as higher plant throughput. Additionally, the initiative has benefited both Brownfield and Greenfield projects on the PPRust operation.

Jan 1, 2005

By W. J. Kogelmann

Roadheaders, also called Boom Miners or Boom-type Tunneling Machines have been in North America since 1968, when first introduced by Willy Kogelmann, the founder of Alpine Equipment Corp. (?Alpine?). Roadheaders were invented in Europe in the late 1940s. Machines with in-line, axial cutter heads were developed in the former Soviet Union. The British Dosco DRCL is based on the Russian PK-3 roadheader. Roadheaders with transverse ?ripper? cutter heads were invented in Hungary (1). The Austrian-made Alpine Miners of VOEST-Alpine, purchased by Sandvik AB, are based on a 1965 Hungarian license. Roadheaders are widely used in the mining and tunneling industries because they can excavate drifts, entries and tunnels with cross sections of any shape and size, can handle mixed faces, work on steep grades, and negotiate tight curves and cross-cuts. A roadheader?s only major limitation is the strength and abrasiveness of rock and minerals to be excavated. This paper covers roadheader selection criteria, improvements in reliability, attachments for flexibility (Multi-Tool Miner), and automated support systems for increased cutting time for increased shift production.

Jan 1, 2008

By Mathew B. Revell, Martyn L. Bloss

The paste fill system at BHP Cannington's underground silver-lead-zinc mine is described. The paste fill system has been operational since December 1997 and is the first of its type in Australia. Technical and operational learnings since stope filling commenced are presented. Topics described include plant performance, reticulation system design and construction, pipe wear and failure, rheology, in situ performance and laboratory testing.

Jan 1, 2001

By P. D. Roa, O. Noirot, H. Owens, D. E. Walsh, J. R. Mokka

Over a period of eight years (1989 through 1997) the Mineral Industry Research Laboratory (MIRL) at the University of Alaska, Fairbanks, AK, has investigated the effects of temperature, residence time and particle size on the degree of low-rank coal (LRC) upgrading for a nonevaporative, hydrothermal drying process, also known as hot water drying (HWD). The following three Alaskan LRCs were used in this study: Usibelli coal (Seam No. 4) from the Nenana Coal Field, Little Tonzona coal from near McGrath, and Beluga coal from the Beluga-Yentna field on the west side of Cook Inlet. Replicated factorial tests were conducted. Experimental results indicate that most of the low-rank coal upgrading via HWD occurs rapidly within the first 10 to 20 min of residence time. Thereafter, the upgrading process slows down, and more than 100 min of additional residence time is required to produce percentage increases equivalent to what was achieved in the first 10 to 20 min. The properties of the hot water dried products were very sensitive to process temperature. Calorific value, carbon and oxygen contents, equilibrium moisture levels and Hardgrove gindabilities all appear to change linearly with temperature within the 275°C to 325°C (525°F to 61 5 OF) range.

Jan 1, 2000

By Ajay Mahajan, Manoj Mohanty, Vishal Gupta

Modern coal processing plants utilize multiple cleaning circuits to efficiently beneficiate different size coal fractions of run-of-mine coal. An older plant optimization approach is to maintain average product quality from individual cleaning circuits at the same level as the given product specifications for the overall plant. However, many past studies indicate that the equalization of product quality approach fails to produce the maximum plant-yield. A newer approach, known as equalization of incremental product quality, requires that the incremental product quality obtained from each circuit be maintained at the same level to satisfy the overall plant product quality. This approach ensures the maximization of plant yield while satisfying a single product quality constraint. However, while dealing with multiple product quality constraints, this approach by itself may not be sufficient to obtain the desired maximum yield. For the simple reason that the dirtiest particle (or group of particles) with respect to one quality constraint may not be the same particle (or group of particles) with respect to another quality constraint, the mass yield versus product quality relationship generated by equalizing different incremental product quality may not be exactly the same. Therefore, an additional search technique has to be utilized to determine the global-maximum value of plant yield. Thus, the main objective of this study was to utilize an emerging optimization technique, known as genetic algorithms (GA) to maximize plant yield while satisfying multiple product quality constraints. The maximum plant yield obtained from this approach was nearly same as the maximum yield obtained by the incremental product quality approach while satisfying one specific product quality constraint. The GA was applied on a coal preparation plant that utilizes four circuit operations - heavy medium bath, heavy medium cyclone, spiral and froth flotation. The results showed that using GA as an optimization process gives 2.56% higher yield that will result in additional revenue generation of $5,120,000 per annum than average product quality approach.

Jan 1, 2005

By D. G. Foot, J. D. McKay, R. A. Ynchausti

The increasing popularity of column flotation as an efficient and profitable mineral beneficiation technique has resulted in the need to perform a study of basic column operating parameters in order to understand mineral behavior in a column. Variation of column rougher flotation parameters on the Nevada Fish Creek fluorite and Utah Collins manganese ores enabled characterization of four beneficiation zones within a column flotation cell. Although specific mineral behavior in each zone was peculiar to the mineral system involved, particle retention time predominantly affected both manganese and fluorite recoveries in the collection zones of the column while enhancing mineral grades in the cleaning zones. Column parameters such as column length, feed injection location, and tailings recirculation velocity were inherently linked to particle retention time and retention time distribution, both of which affected mineral recovery. Froth depth had a discernible effect on fluorite concentrate grades; as froth depth increased, fluorite grades increased. Wash water additions affected both fluorite and manganese recoveries and fluorite grade. Axial mixing drastically reduced fluorite and manganese recoveries due to short circuiting of some of the feed slurry in the column.

Jan 1, 1988

By Roger D. Sharpe

The United States Gypsum Company operation at Plaster City, in Imperial County, California, consists of the largest gypsum quarry in the United States, a company-owned, narrow-gauge railroad and wallboard and plaster manufacturing facilities. A variety of gypsum products, including many types of wallboard, construction plasters, portland cement setting agent, and agricultural gypsum are manufactured. Gypsum is quarried from the Miocene age Fish Creek Gypsum. Evaporite minerals were deposited in a clastic-rich sabkha environment along the margin of a small embayment in the Salton Trough. The Salton Trough is a major regional structure that formed by rifting and transform faulting along the Elsinore, San Jacinto, and San Andreas fault zones. Sedimentary basins were formed between tilted fault blocks. The basins were filled by prograding alluvial fans, basin margin sabkha and marine sediments, and deltaic deposits from the Colorado River. Gypsum is exposed in the quarry on rounded hills with 250-300 feet of relief. The evaporites are up to 200 feet thick and average 125 feet in thickness. Anhydrite commonly occurs in the lower part of the evaporites under the crests of hills and beneath thick alluvial cover.

Jan 1, 1995

By Giin-Fa Fuh, Sally A. Shoop

An instrumentation program was developed based on the results of an analytical study of the geomechanical effects of longer longwall face lengths. Boundary element simulations showed that longer face lengths can cause in- creased face convergence and an increase in the shear stresses in the immediate roof. Empirical design methods predict that longer faces will cause little effect on abutment stresses as long as the roof caving is well behaved. On this basis, a longwall face instrumentation program was designed with emphasis on the interaction between face support and ground response for optimizing face conditions. At a 600-foot (183 m) face, five midface shields and two headgate shields were monitored with vary- ing hydraulic pump pressure. The instrumentation included six convergence rods with linear potentiometers to measure canopy-to-toe convergence; fourteen pressure transducers to monitor leg pressures; and two portable data loggers. Similar instrumentation will be in- stalled on a 750-foot (229 m) face for comparison. The results from the 600-foot (183 m) face indicate that a ground reaction curve, as determined from the relationship between the sup- port set pressure and the roof convergence, can be used to optimize the support pressure to control convergence, the key element to ground stability in the face area.

Jan 1, 1986