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By Z. D. Yu, J. E. Gebhardt, D. I. Phillips, S. X. Jiang, R. Z. Zhang

The potential application of flotation for the treatment and processing of a fine-particle coal stream was investigated for the Chaili Coal Washery of the Zaozhuang Coal Mine Administration, Shandong Province, China. A goal of the test work was to evaluate the application of the Microcel™ flotation column and compare its performance to conventional flotation. Small-scale flotation tests were performed in the laboratory and on-site with fine coal slurry samples from the plant thickener underflow, i.e., the washing plant's undersized reject material. Flotation tests were conducted on-site with a 7.6-cm diameter Microcel™ column and with small-scale conventional cells. Column flotation tests were performed to determine a recovery-grade relationship for the fine coal feed, which contained about 24% ash, and to obtain sufficient data to enable scale-up to a large diameter unit. A primary objective as to establish the maximum throughput capacity of a Microcel™ flotation column while operating to produce a clean coal product with ash content of 7.5-7.8%. Results of the test work indicate that this product quality could be achieved at feed rates of 15-19 tph to a 3-m diameter Microcel™ flotation column. Lower ash products, i.e., 5-7% ash, were obtained but at lower column throughput capacities. Comparative flotation tests, conducted with conventional flotation cells, indicated that a product ash of only 8% or greater was achieved in a single-stage test.

Jan 1, 1995

By Kenton E. McElhattan

Financial analysts have often called National Mine Service Co. the only "pure play" company to the mining industry, meaning that an investment in NMS is an investment in the mining industry. As a leading manufacturer and supplier to the industry, National Mine Service does enjoy a close and direct relationship with mining. It is the only independent company that offers products and services that include mining machinery, health, safety, instrumentation, mine supplies, and reconditioning services for hydraulics, electronics, and machinery. But what is a positive relationship in periods of economic upturn can be eauallv as negative during the downturns. In fact, National Mine Service has felt the resounding blows of the current recession in the mining industry. Two-Fold Strategy Rising unemployment, corporate losses, bankruptcies, and mine closings in particular have directly affected NMS. But the company embarked on a strategy several years ago that included a two-fold approach to becoming less dependent upon the vagaries of the US coal industry. One strategy was to develop additional products and services for other mineral industries such as potash, trona, and salt and, where possible, apply the technology developed for the mining industry to industrial markets. The other strategy was to become a more international company. The objective was to make export sales a minimum of 10% of total corporate sales. Even today, NMS believes this is a good strategy as opposed to diversifying because its expertise is in mining, not in other areas. A review of NMS's fiscal 1982 annual report indicates that the company's strategy did begin to pay off. 1982 was a turnaround

Jan 2, 1983

By Frank H. Blair

A study of paleogeography and paleo-environment, coupled with modern geochemical techniques and geologic inference, points to the presence of unconventional platinum group metal deposits in domestic and foreign ultrabasic terranes. During the laterisation of the tectonized and serpentinized mafic and ultramafic rock units, onshore winds provided abundant low temperature chloride to the laterite-saprolite profile. Here, an environment formed where gold, silver and platinum was dissolved, transported and redeposited. Changes in climatic conditions have helped preserve the redeposited metals in fossil laterites. The definition of "unconventional mineral resources" used here is taken from the Cameron Volume of Unconventional Mineral Deposits published by SME-AIME in 1983: "Unconventional mineral resources represent materials of possible economic importance that occur in geological or physical environments that have not been successfully exploited for the particular mineral." (van Rensburg, 1983). Chromite-rich rocks worldwide contain high platinum group metal concentrations. This feature is found in ophiolitic sequences, Alaskan-type ultrabasic complexes or statiform intrusions. Association of platinum group metals with chromite has received much attention. The reason for that associa¬tion, however, is not clear. Much has been written about how and where the platinum group metals occur. It is known that they are present in the spinel lattice, as solid solution elements in sulfides and as discrete platinum group minerals. This article outlines the reasons geologists should be looking at lateritic terranes to determine the feasibility of searching for undiscovered, low-grade platinum group metals amenable to openpit, bulk mining. Laterite-saprolite horizons could contain significant platinum group metals and location of anomalous values on the surface and in the weathered profile can lead to discovery.

Jan 1, 1993

By Steve Kral

The Fourth International Symposium on Hydrometallurgy was organized to give those in the minerals processing field an opportunity to discuss current topics of interest in the broad field of hydrometallurgy. Held in Salt Lake City, UT Aug. 1-5, 1993, this fourth symposium also paid tribute to Milton E. Wadsworth for his many contributions in this area over the past 40 years. The science of hydrometallurgy has made great strides since the last symposium was held 10 years ago. The use of electrochemical principles and techniques has produced encouraging results. For example, the application of in situ electrode spectroscopy has helped to understand the mechanisms operating in hydrometallurgical processes. Sophisticated computer models have been developed to handle the thermodynamic properties of concentrated electrolytes. However, it is up to the hydrometallurgist to continuing working on bridging the gap between theory and practice. The successful application of solvent extraction-electrowinning (SXEW) is one illustration of the successful transfer of technology. Its widespread use in the United States during the 1980s played a significant role in the revival of the domestic copper industry. Currently, electrowon copper accounts for about 30% of total US production. Impressive developments in precious metals recovery have also occurred. Since the last symposium, carbon-in-pulp (CIP) and heap leaching have become widely used in gold recovery. And recovery of refractory precious metals ores and concentrates by pres¬sure oxidation and bio-oxidation have made significant advances. In all these examples, hydrometallurgy has played a significant role in the recovery of minerals and metals from primary sources. In addition, considerable attention has been focused on the treatment and recovery of values from secondary sources.

Jan 1, 1994

By Keith G. Wallace, Daniel J. Brunner

The traditional approach to mine ventilation planning involved making estimates of airflows, including leakage routes, and summing the corresponding pressure drops along consecutive paths in order to determine the fan pressures required. This methodology changed completely with the availability of computers. Mainframe digital computers began to be used for mine ventilation network analysis in the mid-1960's. Their use spread rapidly throughout the world in the 1970's. Mainframe machines were employed owing to the need for high speed numerical procedures and substantial storage requirements. However, during the past decade, the growing availability of low cost but powerful microcomputers has allowed the development of net- work analysis programs that can handle ventilation systems of hundreds of branches, and which can produce results within a few minutes. This paper discusses recent advances in software and hardware development specific to mine ventilation planning. Software developments include interactive data and output manipulation, graphical representation of output, internal checks on input parameters to preset ranges and subroutines which calculate the gas distribution throughout the network from known gas sources. Hardware advances have led to significant increases in memory to facilitate the analysis of large ventilation models, math co-processor chips which greatly shorten run times, and plotter hardware for graphical output displays. Recent software developments make it possible to graphically display output on printers faster than on standard plotters.

Jan 1, 1989

By Bruce D. Hulman, Robert .. F. Gorman

Introduction Groundwater resource evaluation has historically required extensive field investigative work, usually at great cost. More recently, the advent of the microcomputer has made difficult aquifer and groundwater evaluations comparatively simple and less expensive. A groundwater model is a numeric solution to a set of equations that calculates the water level in an aquifer or other types of water bearing strata. A computer will execute the solution of the set of equations rapidly and thereby permit evaluation of large amounts of hydrogeologic data rapidly. Computer modeling of groundwater resources is very often used to forecast the effects of multiple uses of a single groundwater resource. Modeling of heavily used aquifers has proven to be beneficial for averting problems arising from competitive use of a groundwater resource. This paper describes the work tasks performed in order to evaluate a large alluvial aquifer and thereby predict the hydrologic impact of additional groundwater withdrawal. Purpose and Scope Neyer, Tiseo & Hindo, Ltd. (NTH) was retained to evaluate the groundwater supply potential of the Missouri River alluvium underlying the Fairfax District in Kansas City, Kansas (Figure 1). The proposed groundwater supply is being considered for industrial use as non-contact process water and a heat exchange medium for plant climate control. The anticipated peak groundwater demand is estimated to exceed 30 million gallons per day (MGD) during the summer months, with an average daily demand of nearly 25 MGD. The proposed groundwater supply was to be developed from 15 large-diameter production wells located at positions that would minimize potential interference.

Jan 1, 1987

By G. B. Misra

Attempts have been made during the last three decades to establish a correlation between respirable dust dosage and the degree of progression of pneumoconiosis or silicosis amongst mine workers. Fair correlation has been possible only after the Johannesburg Pneumoconiosis Conference established mass concentration of dust in the respirable size range as the true measure of the incidence of pneumoconiosis. The author had established a good correlation between cumulative total respirable dust dosage as well as cumulative silica dosage and the category of pneumoconiosis according to ILO classification at Mufulira Copper Mine. Studies at Hutti also show a linear relationship between the average cumulative dust and silica dosage md the category of pneumoconiosis. However the maximum tolerable cumulative dust dosage for - prolonged exposure is 182 mg month/m3 - at Hutti as compared to 275 mg month/m3 at Mufulira. Similarly the maximum tolerable silica dosage for - prolonged exposure is Only 35 mg month/m3 at Hutti as compared to 55 mg month/m3 at Mufulira. The TLV for dust concentration at Hutti works out at 0.6 mg/m3 compared to 1.1 mg/m3 at Mufulira and the TLV of silica concentration at Hutti is 0.117 mg/m3 compared to 0.25 mg/m3 at Mufulira. The Hutti figure is however, closer to the TLV of 0.1 mg/m 3 recommended by ACGIH.

Jan 1, 1987

By Vinton A. Garbesi

INTRODUCTION The placing of the monolithic concrete lining of the Bi-County water tunnel illustrates the state of the art in the materials, equipment, methods and productivity available to the industry for this type of construction. This paper describes the management and engineering rationale used by Clevecon, Inc., a subsidiary of S & M Constructors, Inc., Solon, Ohio, in developing the concrete mix designs, the design of the specialized equipment, and the methods used in the manufacture, transport, and placing of the lining. Also discussed are the changes to the reinforcing steel design instigated to facilitate its handling and placing, as well as to enhance the quality of the lining. The intent is to bring to the attention of designers the effects certain design aspects have on the construction of reinforced concrete tunnel linings, as well as indicate the areas where research and development effort should be expended to further reduce costs for this type of construction. GENERAL DESCRIPTION The Bi-County Water Tunnel West is a water transmission main owned by the Washington Suburban Sanitary Commission of Hyattsville, Maryland. The facility was designed by A. A. Mathews Division (formerly STRAAM Engineers, Inc.) CRS Group Engineers Inc., Rockville, Maryland. It is to be utilized as the central feeder of potable water for the northern suburbs of Washington, DC, extending some 4,597 meters from a riser shaft at its western terminus to the eastern interface, with a similar tunnel which extends eastward about 5,180 meters; the majority of its length being under Interstate Highway 1-495. The excavated and finished diameters are 3.8 and 3.05 meters respectively. The reinforced concrete

Jan 1, 1981

By P. Jacquin

Many a deposit estimation has been carried out since geostatistical methods were first implemented. To date however few mining programs have totally been completed and even fewer comparisons can be drawn between estimated reserves and extracted ore tonnages. Aluminium Pechiney work a number of bauxite mines in Southern France. As from 1969 they modified their deposit estimation methods, giving up traditional approaches and opting for geostatistics. At that time, the authors of this paper were entrusted with the first geostatistical estimations and in particular, those concerning the deposits mentioned herein. Over the past decade a number of deposits have been worked out and we thought it interesting to report about comparative results. French bauxite deposits are of the karstic, as opposed to the lateritic, type. The bauxite, formed at some distance of the present-day deposit, was brought to and trapped in limestone karst pits. Subsequent physical and chemical alterations may have taken place : silica and carbonate drifts, recent karst slips. The morphology of these deposits is often rather complicated. The deposits are small from a few hundred thousand to a few million tons at the most. The overburden thickness usually precludes open mining. Mining investments and financial risks are often high, making it necessary to obtain optimal information on the deposit considered for mining. For the three cases brought up in this paper, deposit sizes, exploration methods and conclusions differ. They are brought up mainly to show the advantages inherent to a quality geostatistical study and the lessons drawn by Aluminium Pechiney.

Jan 1, 1982

By R. C. Kirkman

Your interesting and well-written paper brings up the issue of the purpose or use of a mineral property appraisal, specifically the value of these evaluations when the quality and quantity of the mineral resource to be exploited have not been thoroughly investigated. I am not a practicing professional in regards to valuation of limestone investment opportunities. I simply wish to make a few generic observations about the appraisal process in order to stimulate meaningful thinking by appraisal professionals whose reports may be reviewed by professional investors and "laypersons" alike. It is my contention that the analysis given in your paper is very thorough, considering the data that was made available to you. But I would not like to be the person responsible for investment decision making without having a feel for the risk involved. Therefore, the reviewer must classify this type of analysis as relatively "subjective" because they have not received an indication of the inherent risk involved in exploiting a mineral resource. This risk can best be quantified by using probabilistic methods in conjunction with the quality and quantity of the mineral to be produced. Most appraisals passively ignore this problem. Specifically, you have accurately identified the various costs and values entering the economic appraisal process. These can usually be quantified with a great deal more certainty than the capability of the resource to provide 25 years of quality material. Also, in Cases A (West Virginia) and B (Alabama), you are fortunate enough to have previous operations data. What if there had never been production from these properties? How does a potential mineral property investor evaluate the resource capability to meet various projected financial outcomes without spending a good deal of up-front capital to drill and delineate enough quality resources for a 20-plus year operation.

Jan 1, 1990

By Martin C. Jones

INTRODUCTION This paper outlines the methods used to drill and pregrout prior to the excavation of five Mine Shafts in the Coal Measures of the Eastern United States. One example is the use of cement pregrouting of four 240 meter deep shafts and the second is the use of chemical pregrouting of a 360 meter deep shaft. These two examples will be compared and contrasted, both at the investigation stage of each project, and during the drilling and pregrouting itself, to illustrate the different approaches taken and how these affected the outcome, both technically and economically. INVESTIGATION FOR 240 METER SHAFTS In the case of the four 240 meter shafts, site investigation was carried out prior to bid, and information was made available by the Client in the form of a report. This report was based on pressure testing of NQ cored boreholes at each shaft site. Pressure testing was repeated two or more times, at each test setting, using 345 or 690 kPa of water pressure in accordance with the procedure outlined by the U. S. Bureau of Reclamation. Flow readings were taken every minute over a period of ten minutes. Maximum computed permeabilities, for the strata which accepted water under test for the shafts, carried between 1.0 x 10-6 m/s and 3.0 x 10-6 m/s, and total calculated seepages varied between 170' litres/minute to 3891 litres/minute. Although these figures did not indicate an excessive amount of seepage, the Client decided that pregrouting should be carried out, and chemical grouting was not discussed, even though the test permeabilities indicated the use of cement grout would be limited in this case.

Jan 1, 1979

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 Jesse L. . Jr. You

Tunnels in the granitic Climax stock at the Nevada Test Site were inspected for keyblock occurrence. Thirteen relatively large pyramidal keyblocks were located in about 230 m (750 it) of tunnel. Orientations, dimensions, joint roughness coefficients, and joint compressive strengths were measured for the faces of nine keyblocks. The measurements were used to back-analyze keyblock stability to check the validity of a numerical model for keyblock behavior. A newly developed three-dimensional numerical model correctly predicted whether or not each keyblock failed in six of eight cases. The two exceptions involved stress conditions and keyblock locations that clearly violated the assumptions that underlie the stability model. The observations also allowed the effect of tunnel orientation on keyblock occurrence to be evaluated. Of the thirteen observed keyblocks, nine large blocks were found in less than 30 m (100 ft) of the Piledriver drift (which runs N56E) while only four blocks of comparable size were observed in 200 m (656 ft) of the Spent Fuel Test--Climax drifts (N61W). The orientations of the keyblock faces were checked against known discontinuity set orientations; some of the faces correlated well with mean set orientations, whi.le other faces were fringe members of sets. Stereographic techniques were used to examine the frequency of keyblock occurrence and to determine the maximum keyblock size that could be encountered with a given combination of discontinuities. Keyblock occurrence was found to be affected by tunnel orientation in a predictable way; this can be used to guide or improve tunnel design practices.

Jan 1, 1986

By L. Xu, N. I. Jayaraman, R. Bhaskar

The objective of this study is to develop a better understanding of the collection characteristics of dust measurement instruments used in mine dust control research with respect to properties of quartz and coal dust. Coal and quartz dust of narrow sues, with aerodynamic median diameters being approximately 2 µm, 4 µm and 10 µm, with quartz contents of l0%, 20%, 30%, 40% and 50%, were released in an aerosol characterization chamber using a fluidized bed aerosol generator. Dust was collected in MSA personal gravimetric samplers with l0-mm nylon cyclones, total dust samplers and Sierra 298 inertial cascade impactors. The samples were analyzed for mass and quartz content. A total of 21 experiments were performed for this study. The mass and quartz collection efficiencies of the total and respirable dust samplers and the impactor were determined. The data show that the amount of dust collected by the respirable dust sampler (respirable + oversize dust trapped in the cyclone pre-classifier) was, in general, less than the amount collected by the total dust sampler. The amount of dust collected by the impactor was higher than that collected by the total dust sampler. Quartz analyses of the airborne dust samples showed that the total dust and respirable dust samplers (including oversize dust) collect less quartz dust than at inertial impactor. The larger the median particle sire of the quartz and coal mixture, the lower the quart content of the dust collected in the samplers. For all three sires, the impactor was a better collector of quartz than the other instruments.

Jan 1, 1994

By Raja V. Ramani, Sachin Shankar

Re-entrainment refers to dislodgement of particles deposited by both atmospheric and nonatmospheric processes and their subsequent insertion into a flowing field. Formation of sand dunes, snow drifts, soil erosion and fugitive dust emissions are a few examples of the natural occurrence of re-entrainment. Re-entrainment studies have been done for the estimation of potential hazards from nuclear fallouts. The phenomenon of re-entrainment has been utilized for the cleaning of wafers and filters. Re-entrainment is associated with both surface and underground mining activities. However, studies on dust re-entrainment in mine atmospheres are limited. Understanding the re-entrainment phenomenon is important because dust particles lying seemingly harmless on the ground and adhering to numerous surfaces can get re-entrained and become a health and safety hazard. There are significant differences in the kind of re-entrainment encountered in underground mines and those in other fields of interest. These major differences are air velocity, direction of air flow, particle size, amount of particles, and time of exposure. While numerous studies have been done in other fields to identify the role of interacting variables and their contribution to the mechanisms of re-entrainment, no similar reported work is available for dust in mine atmospheres. In this paper, recent research efforts on re-entrainment are reviewed. The most suitable form of representing re-entrainment in underground coal mine atmosphere is presented. Various approaches to studying re-entrainment phenomenon in mines are also outlined.

Jan 1, 1991

By D. M. Kjos

Large-diameter autogenous and semiautogenous grinding mills represent the primary thrust of the expanding grinding technology. In spite of initial difficulties, large autogenous and semiautogenous mills have reached an acceptable level of technology that provides the mineral engineer with a reliable, low cost means of ore comminution. A successful milling installation begins during the design stage of the grinding mill and the plant in which it is to be installed. This is particularly true in autogenous and semiautogenous mills. Critical mill and plant design factors should be considered while the mill and installation are still only "paper." Various current liner designs will be discussed ranging from lifter bar/plate to integral types. Modes of operation such as "high-low" will be considered. Liner maintenance procedures ranging from laydown area in plant design, proper mill shutdown methods, to installation and bolt tightening complete the equation to yield optimum performance possible for any particular grinding application. The objective of this paper is to discuss trends in wear materials, designs, and operating practices, and to provide some guidelines for good practice as we move through the 1980s. We will put together concepts that relate to the designs, materials, and applications so that higher performance can be obtained by the operator for his specific application. The concepts are shown as being in series became they are dependent on each other to achieve the desired performance: designs times materials times application results in higher performance (Arnson, Parks, and Kjos, 1983).

Jan 1, 1987

By Malcolm J. McPherson

Observations of environmental parameters in mines have traditionally been made by means of hand-held instruments, these being employed as a basis to ensure that atmospheric conditions in the mine remain within limits commensurate with safety, to safeguard the health of personnel, and to ensure that statutory requirements are met. Thus, starting from the first flame safety lamps of the early nineteenth century, numerous portable instruments have been devised over the years to indicate levels of dust, temperature, humidity, and concentrations of gases including oxygen, methane, and carbon monoxide. Similarly, portable instruments have been used to measure air velocity and pressure. For routine monitoring purposes, hand-held equipment suffers from many disadvantages. Readings are intermittent, often with long delays between successive observations, making short-term trend analysis impossible. Portable instruments are more liable to damage; they are labor intensive and provide a very limited amount of information either for control or planning purposes. The 1960's and 1970's have seen an accelerated development of mine environmental monitoring equipment. Alarm methanometers to give localized audiovisual signals became more common. These were followed by a variety of instruments which gave local, then local/remote continuous records, particularly of methane concentration and airflow. More sophisticated transducers and transmission systems were developed allowing further parameters to be monitored. This led to a proliferation of paper strip and chart recorders which had to be maintained and inspected regularly for trends and abnormalities.

Jan 1, 1979

By M. J. McPherson, P. Mousset-Jones, J. Banik, F. Calizaya

Friction factors or coefficients of friction used to estimate the resistances of mine airways are, in the main, estimated from empirical measurements made in other airways considered to be of a similar geometry and type of lining. A somewhat more analytical approach, although still based on empiricism, is to estimate the ratio of the average height of the asperities to the hydraulic mean diameter of the airway (e/D ratio) and then to employ the Moody Chart or one of the equations that have long been established to represent the [coefficient of friction v Reynolds number curves] on that chart. Unfortunately, the Moody Chart and corresponding equations are based on pipes of uniformly distributed (sand grain) roughness whereas the asperities that exist on the surfaces of mine openings are frequently highly irregular both in their size and distribution. This is considered to be a major cause of discrepancies that have been found between coefficients of friction by the Moody Chart and those actually measured in mine airways. The work described in this paper examines an alternative method of estimating coefficients of friction for rough natural surfaces with uneven sizes and distribution of surface asperities. The technique utilizes the relatively recent developments in fractal analysis. A fractal dimension is determined from the topography of the surface. This has been correlated to coefficient of friction for a scale model of a mine airway. Further work is being carried out in actual mine airways. However, at this time, it appears promising that the fractal method may allow coefficient of friction to be predicted for given types of strata and method of roadway drivage.

Jan 1, 1993

By Gustavo G. Pilger, Jair C. Koppe, João Felipe C. L. Costa

Information for mine planning requires to be close spaced, if compared to the grid used for exploration and resource assessment. The additional samples collected during quasi-mining are frequently located in the same pattern of the original diamond drill holes net but closer spaced. This procedure is not the best in mathematical sense for selecting a location. The impact of an additional information to reduce the uncertainty about the parameter been modelled is not the same everywhere within the deposit. Some locations are more sensitive in reducing the local and global uncertainty than others. This study introduces a methodology to select additional sample locations based on stochastic simulation. The procedure takes into account data variability and their spatial location. Multiple equally probable models representing a geological attribute are generated via geostatistical simulation. These models share basically the same histogram and the same variogram obtained from the original dataset. At each block belonging to the model a value is obtained from the n simulations and their combination allows one to access local variability. Variability is measured using an uncertainty index proposed. This index was used to map zones of high variability. A value extracted from a given simulation is added to the original dataset from a zone identified as erratic in the previous maps. The process of adding samples and simulation is repeated and the benefit of the additional sample is evaluated. The contribution of an extra sample was evaluated locally, globally and in terms of variation in total measured resources. The procedure showed to be robust and theoretically sound, mapping zones where the additional information is most beneficial. A case study using coal seam thickness illustrates the method.

Jan 1, 2002

By J. Herbst, H. B. Treweek, V. R. Degner, G. Poling

Current mineral industry trends toward handling the high tonnages of lower grade ore and tailings retreat lead to a continuing need for large volume flotation cells. The benefits which accompany the larger cell flotation circuit include reduced capital cost, less mill floor space, reduced operational complexity, and less maintenance, provided the metallurgical performance and solids suspension capability of the cell are not compromised. This study reviews development considerations pertinent to large mechanical air induction type flotation cells from the standpoint of cell internal hydrodynamic characteristics and metallurgical performance. While the importance of process related factors such as chemical usage, pH control, solids size and loading, and circuit arrangement cannot be denied, this study will emphasize the relationship of cell size (volume), mechanism geometry (impeller diameter), and mechanism operating conditions (rotor speed and submergence), to air transfer, liquid circulation, liquid "rise velocity" and mechanism power draw. Specific hydraulic performance maps for large capacity 300 and 500 cu ft flotation cells will be reviewed in terms of the relationship between the operational variables and the air and liquid flow conditions within the cell. Metallurgical results, obtained under plant operating conditions for 300 and 500 cu ft cells, are included to illustrate the metallurgical performance similarity of flotation cells which follow hydrodynamic scale-up criteria set forth in this investigation.

Jan 1, 1976