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By Donald T. Mylar

It is axiomatic that in designing a bulk material handling system the primary consideration is the functioning of the machines. The structure is secondary -its reasons for being are to support, enclose and provide access to the machine, for servicing. This results in a wide variety of supporting structures. Other considerations are: plant layout, local soil conditions, climate, local laws and codes, and last, but by no means least, the Customer's wishes.

Jan 1, 1971

By Raymond E. Zimmerman

The use of standard dense-media cyclones is well known, as they have been in use for many years. They are especially well suited for operating at low separating densities and for treating difficult coals containing a high percentage of near-gravity at the point of separation. Very few modifications of the basic design have ever been made. The author recently, however, has been interested in the development of a new type of dense-media cyclone that has been produced in Japan. He has observed the testing of this unit and has collected much data which he feels should be of considerable interest to coal preparation engineers. He feels that this unit, called the Swirl Cyclone, may be of substantial value as an alternate to the standard cyclones. It is certainly worthy of further investigation. There has been relatively little written in English-language publications on the Swirl Cyclone. It was briefly described at the Fifth International Coal Preparation Congress. I It has been described in a general manner by the author in two prior publications. 2, 3 This paper proposes to describe this device in more detail and at the same time submit technical data illustrating its wide characteristics.

Jan 1, 1977

By A. Noble

"Linear circuit analysis (LCA) is a fundamental tool that may be used to evaluate, design and improve the performance of mineral separation. The traditional LCA methodology provides a comparative evaluation of circuit designs purely from the unit interconnections. The quantitative approach uses the analytical circuit solution to evaluate the slope of the circuit’s partition curve at the midpoint. Since the partition slope is often associated with a separation’s general selectivity, this numeric value is used to compare and rank alternative configurations. Unfortunately, the partition curve slope only reflects the separation potential of middling material. By itself, this value does not account for the relatively high unit dollar value of pure material or the gains and losses in mass yield associated with alternative circuit configurations. Realizing the value in the LCA methodology, but respecting the limitations of the partition slope valuation, the authors have derived two new performance indicators that quantitatively address pure particle misplacement (the Partition Moment of Inertia) and circuit mass yield (the Yield Score). Together, these parameters provide a better indication of separation economics in typical mineral and coal separation systems. Since the two parameters provide independent information on circuit selectivity and circuit yield, a Pareto efficiency, multi-objective function selection approach is proposed for preliminary circuit selection.IntroductionOver the past 30 years, numerous scientific and industrial studies have proposed various mineral processing circuit design methodologies that attempt to optimize the allocation of separation resources within the processing plant. Over this period, the methodologies have undergone various transitions, including the increased inclusion of process models and computationally intensive algorithms, as well as a general shift from a purely technical solution (Lauder and McKee, 1986) to partially economic solutions (Abu-Ali and Sabour, 2003; Cisternas et al., 2014). Today, circuit design is largely driven by flowsheet simulation; however, no consistent design methodology is used across the industry.One intriguing approach for circuit evaluation is linear circuit analysis (Meloy, 1983a). This method evaluates the separation potential of the circuit solely considering the unit configuration and stream interconnections. No preliminary data other than the basic circuit configuration is required to use the approach."

Jan 1, 2015

By Susanne Pignolet-Brandom

Flash smelting products of a copper sulfide concentrate collected at successive levels in an experimental reactor have been studied by reflected light microscopy, scanning electron microscope - energy dispersive analysis and electron nicroprobe analysis. Chalcopyrite, intermediate solid solution, bornite, chalcocite, metallic copper, magnetite, iron-copper spinel, pyrrhotite, hematite, delafossite and cuprite have been identified in the product samples. The detailed reflected light microscopy study of these phases and their abundance in the samples has resulted in the identification of the series of reactions during flash smelting.

Jan 1, 1985

By J. J. Sense

The Mission Unit of American Smelting and 'Refining Company is located in Pima County, Arizona, approximately twenty miles southwest of the City of Tucson. The Unit consists of an open pit copper mine and concentrator. The concentrate is shipped by rail to Company Smelters at Hayden, Arizona, or El Paso, Texas Mine stripping began at Mission in the fall of 1959, and construction of the 15,000 tons per day concentrator gas started in the spring of 1960, The first ore was treated in mid summer of 1961 and full ore production was reached in August of 1961. At that time over 46,000,000 tons of material had been moved from the pit. Current production (ore and waste) averages over 100,000 tons per day. Total production to date (ore and waste) over 120,000,000 tons.

Jan 1, 1964

By K. Peri

The leaching behavior of gold in ammonical solutions with iodine as an oxidant has been investigated using cyclic voltammogram and Tafel polarization. The majority of experiments was carried out at 75°C and the results were compared with the equilibrium consideration on the iodine-ammonia system. The distribution of nine iodide containing species at various pH values in the absence and presence of ammonia was considered at three different temperatures. It was found that by introduction of ammonia into the system, the concentration of iodide (r), iodine (12) and triiodide (13') is increased substantially which in turn helps the rate of dissolution of gold. The apparent activation energy was found to be about 46 kJ/mole, indicating a chemical controlled mechanism.

Jan 1, 1999

By S. K. Kawatra

The fly ash from coal combustion often has a high unburned-carbon content. This can make it unusable as a cement admixture, which is the major fly ash utilization market. As a result, high-carbon fly ashes currently disposed of by landfilling, at sometimes considerable expense. In this paper, the use of froth flotation to remove the unburned carbon from fly ash is described. Three different fly ashes were studied, which had Loss-on-Ignition (LOI) values of 6.79, 6.90, and 11.11 %. It was found that the use of an alkanolamide/oil mixture as a froth-conditioning reagent could greatly reduce the amount of collector needed, by increasing the affinity of the collector for oxidized carbonaceous surfaces. For each of the three fly ashes, froth flotation reduced the LOI of the ash to less than 2% which is well below the ASTM specification of no ' more than 6.0% LOI for Class F fly ash. Increasing carbon content of the ash tended to increase the quantities of reagents needed in flotation.

Jan 1, 1996

By Jan Reimann

Increasing individualization with smaller quantities, growing competition from low-wage countries, and the continuous drive towards digitalization are the challenges that industrial companies in high-wage countries must face. The example of the Flender One gearbox modular system demonstrates how consistent standardization and digitalization are the enablers for AI, and thus already enable new business models and business approaches today.

Feb 22, 2026

By Joshua Cole, Joshua Sovechles, Christian Cardoso, Guillermo Bermudez, Martta Hirsi, Joshua Dettamanti, Rabia Abbasi

The implementation of technological advancements in flotation is key to optimize performance in mining operations. Consequently, flotation cell’s performance is highly dependent on the effectiveness of the mixing mechanism. A more efficient flotation mixing mechanism is likely to improve metallurgical performance and optimize energy consumption, which is the motivation for Metso’s journey to develop the latest iteration of FloatForce®. Looking to test the new design at plant scale, Metso approached the Kennecott Copperton concentrator, which is continuously looking for different venues to improve metallurgical performance. In this context, a test campaign was conducted to implement this new flotation mixing mechanism in their rougher circuit during 2024. The industrial trial consisted of several sampling campaigns assessing different operational parameters for comparison purposes around a 300m3 flotation cell. The effect of the new flotation mixing mechanism on the cell’s power draw was also studied. The results of this trial at Kennecott are presented in this paper. Overall new flotation mixing mechanism, FloatForce+ was seen to perform as well as the original FloatForce.

Feb 1, 2025

By L. J. Drew

The plate tectonic setting, regional geology, and certain aspects of the economic geology of the iron-rare-earth-nio-bium ore bodies at Bayan Obo, Inner Mongolia, China, were studied by a team of geologists from the Tianjin Geologic Research Academy and the U.s. Geological Survey between 1987 and 1989. These ore bodies were formed by hydrothermal replacement of Middle Proterozoic dolomite in an intracontinental rift setting. A variety of veins and/or dikes that have a carbonatite-like mineralogy cut the footwall clastic rocks and migmatites. A stockwork of veins occurs at several locations in the footwall. The hanging wall is a shale that has been converted to a K-metasomatite and has microcrystalline potassium feldspar as its principal constituent. This shale served as a sealing caprock that contained the chemical solutions that reacted with the dolomite and that created the enormous concentration of mineralized rock in an 18-kilometer-long syncline. The rocks that host these ore bodies and the associated mineralized areas occur today as roof pendants in granitoid rocks of Pennian age that were emplaced during a continent-to-continent collision during that period.

Jan 1, 1991

By M. Sadegh Safarzadeh, Erich U. Petersen, Jan D. Miller

"An acid bake-leach process has been identified and applied to an enargite concentrate containing ~67% enargite, ~27% pyrite (FeS2), ~3% chalcopyrite (CuFeS2), ~6% sphalerite (ZnS) and <1% galena (PbS). Sulfuric acid baking of this concentrate resulted in the transformation of the concentrate to S8, As2O3, HFe(SO4)2•4H2O, PbSO4 and Cu0.47Fe0.53SO4•H2O, all of which (except elemental sulfur and PbSO4) dissolved during the water leaching step. More than 87% Cu and 64% As were leached when the concentrate was baked at 200°C over 7 hours with a sulfuric acid-toconcentrate weight ratio of 1.6. Less than 1% As was lost to the gas phase. Upon water leaching, copper and arsenic were released to the solution at a concentration ratio of about 3:1. While enargite is very reactive during the sulfuric acid baking reaction, other minerals present in the concentrate such as pyrite, galena and sphalerite may compete to consume sulfuric acid and be converted into their corresponding sulfates at different concentrations. The purpose of this paper is to present our examination of the effects of sulfuric acid dosage on the extractions of Cu, Fe, and As from an enargite concentrate. In this regard, the concentrate, baked concentrate, and the leach residues are characterized and a conceptual process flowsheet is described for the acid bake-leach process for the treatment of enargite concentrates.IntroductionThe occurrence of enargite (Cu3AsS4) in copper ores and concentrates and the associated high arsenic values in such resources have resulted in a considerable decrease in the demand for such concentrates because they cannot be economically processed using conventional technologies such as smelting and atmospheric leaching (Mihajlovic et al., 2011). The exploitation of such problematic deposits through competitive treatment strategies will be required in the near future in order to satisfy increasing pressure from the copper market. It is expected that the average arsenic grade of copper concentrates will increase from 0.17% in 2008 to 0.22% by 2020 (Mayhew et al., 2011).The acid bake-leach process was identified and selected for further investigation at the University of Utah as a possible process alternative for the treatment of enargite concentrates. In this case, adequate amounts of concentrated sulfuric acid are mixed with the concentrate and heated to the temperature range 150-300°C. Subsequently, the baked material is leached with water/weak acid and the acid bake-leach process has some advantages over conventional sulfuric acid leaching (Prater et al., 1970). During water leaching, metal sulfates are released in solution, after which they can be extracted through well-known hydrometallurgical techniques. While the majority of the work has been done on oxide minerals, there is a limited record of sulfuric acid baking of sulfides."

Jan 1, 2015

By V. R. Burkhart

Pennsylvania Power & Light Company is an investor-owned public utility which was incorporated under the laws of the Commonwealth of Pennsylvania on June 4, 1920, with general offices at 901 Hamilton Street, Allentown, Pennsylvania. At the present time PP&L is operating five coal-fired steam electric stations, two hydroelectric stations and one steam heat plant which is being converted from anthracite to oil fired. In addition, PP&L is a partner in both the Keystone and Conemaugh mine mouth bituminous coal-fired steam electric stations in Central Pennsylvania and also part owner of a company which operates another hydroelectric station. PP&L plants, other than the two mine mouth stations, are located in Central Eastern Pennsylvania. (Figure 1) The company derives about 99% of its operating revenues from supplying electric service, while the balance is from the one steam heat plant serving the city of Harrisburg. The entire service area covering 10,000 square miles in 29 counties, has a population of approximately 2,300,000 people. The area served is mostly suburban. It includes 109 communities each having a population in excess of 5,000 people. The largest cities served are Allentown, Bethlehem, Harrisburg, Hazleton, Lancaster, Scranton, Wilkes-Barre, and Williamsport which range from 50,000 - 120,000 in population. So you see our service area does not include any major cities. The area has industrial, commercial, residential, agricultural and recreational activities that are linked with the Eastern Megalopolis by an extensive interstate limited-access highway system and railroad networks. We consider this Central Eastern Pennsylvania area we serve as the "heart of the market" -- an area with great growth potential.

Jan 1, 1973

By R. R. Rollins

Field data combined with theoretical derivations were used to design a surface mining operation using explosive casting. Calculated casting results varied from 44 to 65% depending on bench height. This model was then applied to field tests at an eastern, contour, coal stripping operation. Results from five experimental casting shots are summarized and compared to conventional mining methods. The overburden material removed by casting ranged from 35 to 65% with an average of 50%. Fragmentation was improved and it was demonstrated that this procedure is economically attractive with a resultant cost savings of $.59/m3 or $5.93/t of clean coal.

Jan 1, 1987

By S. P. Winkelmann

The expansion in gold production in the Carlin &apos;Trend over the last few years has been one of staggering proportion. To increase gold production while minimizing capital requirements and providing for the safe and efficient mining and processing of ores has required a tremendous effort by the Mine Engineering group at Newmont Gold. This paper discusses the organizational changes implemented to effectively deal with a full range of engineering problems and how the Newmont Gold Mine Engineering group dealt with these problems. Specially developed computer software and their applications will be explained. Improvements in the techniques used in converting geologic resources into reserves, and in scheduling the mining of multiple pits to feed multiple processing facilities, as well as ore control procedures are presented. Current mine engineering practices are discussed.

Jan 1, 1990

By Jorge Armstrong, Sean Warren, JOSEF BOURGEOIS

The application of statistical analysis software programs has proven useful for the investigation of rockfall runout distance along a designed slope. Rockfall modeling programs are continually being upgraded with more sophisticated analysis tools, such as the use of the rigid body versus lump mass models. Engineers at mine sites utilizing the software may have varied experience related to these models, their associated input parameters, and how to interpret the generated results. To address this concern, researchers at the Spokane Mining Research Division (SMRD) of the US National Institute for Occupational Safety and Health (NIOSH) investigated the influence of slope height, slope angle, slope material, and rock size for both rigid body and lump mass models in a 2-D statistical analysis program. Based on a literature search and industry input, specific ranges common to that of an open pit mining environment were chosen for each of the input parameters to determine 90% rock runout distance as well as their sensitivity to change. Data collected from this numerical analysis and simulation will be compared to empirical rockfall data gathered through the duration of the Highwall Safety project conducted by NIOSH from 2022–2026.

Jun 18, 2023

By G. S. S. Raman, M. S. Klima

The effects of pressure and cake thickness were studied using a split-plot design for pressure filtration of a fine refuse slurry obtained from a bituminous coal preparation facility. Pressure filtration offers the potential to significantly reduce the moisture content of the fine refuse stream with the addition of little to no flocculants, thereby minimizing the volume of refuse stored in impoundments and providing a recycle water stream for use within the plant. Experimental results showed that the final cake moisture decreased with increase in pressure and decrease in cake thickness. In addition, specific cake resistances calculated for the various tests indicated an increasing trend with increasing pressure and decreasing cake thickness. With increase in cake thickness, an increase in cake moisture and the weight of solids deposited in the cake was observed. An ANOVA analysis indicated that both cake thickness and pressure significantly affected the cake moisture, while only cake thickness statistically influenced the weight of solids in the cake. A regression model was developed with an R2 value of about 0.99 to relate cake thickness, the single largest statistically significant factor, with the weight of solids in the cake. Filter capacities were calculated in terms of the solids deposited per unit time based on a product specification of 25 percent cake moisture, and it was observed that the thinnest cake had the highest filter capacity.

By Dennis E. Peterson

Land subsidence had been observed in recent years throughout the Southwest. Particular examples of this phenomenon that have gained wide publicity axe in the Long Beach and Central Valley areas of California and, the Houston area of Texas. Less well known is the fact that the land surface Is subsiding in many parts of Arizona, including the Phoenix area. The causes of this problem vary from place to place, as do also the rates of subsidence. In Houston it has been related to pumping water from artesian aquifers; in Long Beach to the development of oil fields; and in the Central Valley to both the lowering of artesian pressures in deep aquifers and the wetting of poorly consolidated surficial deposits. The mechanism by which subsidence occurs in southern Arizona, even though it can be correlated with the continued lowering of ground water levels, is not as apparent as in these other cases. It is the purpose of this paper to examine both the causes and affects of land subsidence in southern and central Arizona.

Jan 1, 1965

By J. Ludden

By Sims Some two years ago we began investigating low coke button bituminous coal for use at our Bound Brook, New Jersey plant as a replacement for anthracite. Since August, 1957 the plant has been operating continously on this coal with the exception of a new 200,000#/hr, cyclone boiler. This study was motivated not from our desire to conduct combustion research, but for the sole purpose of reducing our steam costs, The indications were that the economics were greatly in favor of the use of the bituminous coal. The attempts to reduce the costs have developed some knowledge that has enabled this program to succeed reasonably well as will be discussed later by Mr. Ludden. The production of steam size anthracite is dependent upon either the reclamation of old culm banks or the breakage in the production of the domestic sizes. The anthracite industry has not as yet been able to cut, its mining costs to the point where the production of steam sizes has become a profitable business. This has resulted in two basic problems: (1) A constantly rising price in an attempt to have those sizes carry their share of the cost and, (2) Periodic shortages of supply when the demand is good but the market price prohibits the mining of anthracite to produce those sizes only, These conditions have made the long range forecast appear as though the price would go even higher and/or the supply at times be critically short.

Jan 1, 1958

By C. T. Holland

Coal mining has been an important industry in the Appalachian area for many years. This is particularly true in the northern part of the area, namely, in Pennsylvania, West Virginia, and Ohio. Also, in the south a great deal of mining activity has been carried on in Alabama, Kentucky, and southwest Virginia. Some of the by-products of this activity has been the production of mineralized water from the mines in copious quantitites. The southern Appalachians have been somewhat more fortunate in that the water there has had a considerable amount of alkalinity in it, which has to a large extent eliminated some of the more undesirable aspects of mine drainage. Northern Appalachia, including central and western Pennsylvania, the Monongahela basin in West Virginia, and the Appalachian area in eastern Ohio have not been so fortunate in that coals in those areas and the top and bottom rock have, in many cases, shown considerable quantities of pyrite, and the water does not carry the carbonates found farther south.

Jan 1, 1969

By W. Joseph Schlitt

The use of plate and frame filter presses for dewatering cement copper at Kennecott&apos; s Bingham Canyon precipitation plant is described. The dewatering process begins by periodically flushing a dilute copper slurry from cone precipitators to a rake thickener. The thickener underflows intermittently to an agitated surge tank which feeds the filter presses with a relatively constant slurry containing 10 to 20% solids. The presses operate with a three-stage cycle; loading, air blowing and discharging. Exothermic reactions occur during the air blow which cause actual drying as well as promoting dewatering via simple filtration. At the completion of the air blow, the presses are discharged onto a conveyor belt which transfers material to the load-out building for shipment to the smelter. An extended investigation was undertaken to relate moisture content in the filter cake to maximum press temperature, acidification of press feed, percent solids in the feed, and percent insol in the copper. Of these, press tempera¬ture and feed pH (3. 5 to 1. 0) have the greatest impact on drying. Because the discharged filter cake is hot and continues to undergo exothermic oxidation, significant drying occurs during subsequent handling so that a product containing 8 to 14% moisture is delivered to the smelter.

Jan 1, 1977