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By John L. Schaller

The Bureau of Mines, U.S. Department of the Interior, has investigated the extraction of alumina from domestic kaolin clay by leaching with boiling 26 wt-pct hydrochloric acid. Acid leaching of crushed calcined kaolin feed yields slurries that are slow settling and difficult to filter because of the presence of fine particles generated in crushing, calcining, and leaching. Laboratory research showed that tumbling and moistening crushed raw kaolin on a pelletizing disk caused the fines to agglomerate on the surfaces of the larger particles, while the sharp edges and corners of the larger particles were rounded off. Minus 16-mesh crushed raw kaolin was misted on a 36-in-diam, 8-in-deep pelletizing disk at rates of 175 to 250 lb/hr, and was calcined in either a rotary or a fluidized-bed calciner; negligible degradation occurred. The physical properties of the misted calcined kaolin were evaluated in the leaching system of the clay-hydrochloric acid miniplant. Only minor attrition occurred during leaching, and the slurry was readily filtered on a continuous belt filter.

Jan 1, 1982

Drilling in the south of the Rapahoe Sector at Greymouth Coalfield has demonstrated the existence of thick coal seams in the upper Rewanui Member. Seam correlation is handicapped by complex lithostratigraphy and laterally variable geophysical log profiles. An integrated investigation of coal measure stratigraphy, coal petrology, and proximate analyses, suggests a feasible model whereby most of the major seam intersections belong to a single horizon. Coal properties vary laterally in response to original swamp conditions, which are believed to have ranged from well-drained to ponded. A new model of peat accumulation is proposed for the northern Rapahoe Sector, whereby Upper Rewanui peat accumulation occurred on a flood plain between the levees of a major south southwest-flowing fluvial system in the east and the toe of a western alluvial fan.

Jan 1, 1985

By F. J. Tavera, J. A. Finch

A probe suitable for on-line measurements of gas hold-up in industrial flotation systems has been developed. It is based on an open cell for measurement of slurry-gas conductivity and a novel syphon cell for measurement of slurry-only conductivity. The desired behaviour of the two cells was demonstrated and estimates of gas hold-up were shown to be in good agreement with independent measurements. The gas hold-up probe was used as a diagnostic tool to assess the operation of flotation columns. Differences in gas hold-up between baffled sections in two industrial columns were detected

Jun 18, 1905

By R. Kramer, A. Habibi

A ventilation survey was conducted in an underground longwall trona mine. The mine is relatively shallow and categorized as a gassy mine. The ventilation system includes three intake and six exhaust shafts, and three surface axial fans ventilate the mine in a blowing configuration. Airflow quantity, pressure losses and air psychrometric characteristics were quantified, and the influence of moving cages and skips in the shaft examined. The benefits of utilizing high-accuracy digital pressure transducers and advanced psychrometers were seen when undertaking a “leapfrogging” survey to gather data needed to build a computer ventilation model. Two underground booster fans with VFDs are idle but available at the mine. The ventilation model was used to determine the optimal booster fan locations to decrease operating cost by reducing the load carried by the main fans. A leakage study was conducted to evaluate the effects on the system of additional pressure from a booster fan. The study finally prepares a future ventilation model for the next 15 years of mine operation and investigates the effect of proposed scenarios.

Jan 1, 2014

In mining industries, materials loading and handling costs represent a significant component of the total (capital and operation) costs. A variety of methods have been applied in surface mine equipment selection in order to select the suitable loading and haulage system with the lowest total cost. The optimal size and number of equipment calculation are very important task for mining engineering because loading and haulage equipment are major proportion of open pit mining cost. Capital and operating cost are considered in objective function with respect to interest rate, insurance and tax in non-linear form. Shovel and truck annual productivity constraint, fleet matching constraint and number of truck per shovel constraint are incorporated in this optimisation problem with continuous variables. This formulation will yield total cost minimisation per hour and good accuracy compared to previous methods.

Dec 6, 2010

By M. C. Pietrobon

"A common problem in assessing the applicability of laboratory flotation data is determining how closely conditions during laboratory testing of the ore matches those that occur in a plant. Typical laboratory based investigations do not consider factors such as water quality, pulp temperature and the pulp chemical environment during both grinding and conditioning on laboratory flotation performance. Disregarding these important factors may seriously compromise the validity of conclusions based solely on laboratory experimental results. Furthermore, considering these factors during the flowsheet design stage in the development of new ore resources may reduce financial risk associated with building a new plant. A methodology is described here which embraces these factors in an attempt to bridge the gap between laboratory and plant. The methodology should be considered a vital first step in all laboratory based experimental programs and has implications for fundamental studies on the flotation behaviour of single minerals. This methodology increases the confidence with which findings of laboratory based studies can be transferred to the plant and highlights the effect of variables which may be accessible to manipulation in the plant.Pulp chemical parameters, such as pulp dissolved oxygen demand, pH, Eh, mineral oxidation and solution composition were manipulated in the laboratory by adjusting the duration of gas purging after grinding, the process water input and pulp temperature. A key finding was that matching of the laboratory pulp chemistry to the plant pulp chemistry was dependent upon oxidation after grinding. In turn, mineral oxidation was dependent upon the pH in grinding, water composition and the duration of oxygen purging after grinding. The methodology closely matched the dissolved oxygen demand and surface chemistry of laboratory and plant pulps."

Jan 1, 2002

By Ranajit Kumar Sahoo, Shatrughan Soren, Surendra Kumar Biswal, Soumya Sahoo, Sachida Nanda Sahu

The presence of appreciable quantity of clay mineral in Indian hematite ore needs an attrition technique using screw scrubber in the beneficiation circuit to remove the ultrafine clays and avoid downstream operational problems. Spectroscopic analysis revealed that iron ore samples obtained from the Barbil region of Odisha contain a high amount of silica and alumina in the form of clay minerals (e.g., kaolinite) contributed as a loss on ignition (LOI) in the iron-making process. Iron ore fines of below 10 mm size were subjected to a laboratory-scale screw scrubber, and the effectiveness of scrubbing as well as the pelletization of the scrubbed product was investigated. The screw scrubber in the beneficiation circuit helps to remove the clay minerals, causes an increase in iron values from 63.65% Fe(T) to 66.18%Fe(T), with improved physical (CCS of 325 kg/pellet) and metallurgical (RDI of 2.24%) pellet properties.

Aug 31, 2020

By Rick Wilkins

The stability of steep embankments is a major safety issue in open pit mining, highway passes, and earth filled dams. A failure in any one of these situations could mean a loss of very expensive equipment, a long term inconvenience, and more importantly, a loss of life. These possible catastrophes could be avoided by installing a reliable real time monitoring system. Robotic total stations (RTSs) give one possible cost effective solution to creating a near real time monitoring system. Repeated surveys at predetermined time intervals can automatically generate warnings if slope movements exceed a preset tolerance level. The variation in atmospheric refraction, combined with possible instabilities in reference targets, can make a monitoring system based on RTSs produce false alarms. A methodology has been developed at the Canadian Centre for Geodetic Engineering (CCGE) for reducing these systematic error effects. The methodology has been realized in the creation of a software package that has been successfully implemented at large earthen dams in California and at an open pit mine operation in British Columbia.

May 1, 2002

By B. Kolonja

This paper considers simulation of truck dispatching system designs using maximum expected production of the truck-shovel system as the measure of performance. Two methods are utilized, multiple comparisons with the best (MCB) and the combination of MCB and the variance reduction technique known as common random numbers (CRN). These two techniques are compared via simulation experiments. The results show that the combined procedure of MCB with CRN is the superior tool to reduce the total number of replications needed to ensure the specified probability of correct selection over the finite number of designing systems. In this case study, MCB with CRN reduces the variance by 29% and the number of required replications by 48%. Also, the MCB with CRN procedure narrowed the confidence interval by 18%.

Jan 1, 1994

A geologic, petrographic and geochemical study has been performed on the pyroclastic flow deposits in the coastal area of East Zhejiang Province, Southeast China. This study leads to classification of the pyroclastic flow deposits into three associations: the extrusive type, the surge type and the ash flow type welded tuff associations. Through detailed investigation and comparison of the characteristics of these lithologic associations, with emphasis on the welded tuffs, a comprehensive model has been proposed to demonstrate the petrogenesis of the pyroclastic flow deposits.

Jan 1, 1995

By T. Deng

Flotation of rare earths is complicated by the number of mineral classes that carry rare earth elements, including carbonates, phosphates, and silicates that often co-occur within the same deposit. Gangue constituents often belong to the same mineral classes as the rare earth minerals themselves. Chemical regimes developed for specific separations employ customized combinations of collectors, modifiers, and depressants that are not directly translatable to other operations. In this rougher flotation case study, a reagent suite including phosphate ester and sulfosuccinamate, originally developed for the recovery of bastnasite and monazite from silicate hosted ore, could not be applied to a synchysite ore hosted in carbonate gangue because the suite was aimed at silicate gangue rejection only. The separation of a fluorocarbonate mineral from carbonate gangue required a different chemical regime involving the use of hydroxamate and sodium silicate. Maximizing rare earth recovery was complicated by the presence of slimes. The effect of desliming and the increase in grind size was explored.

Jan 1, 2014

By A. T. Harris

Ground quartzite, known in the industry as amorphous silica, is produced from a quartzite deposit near Honey Brook, Pa., by George F. Pettinos, Inc., of Bala-Cynwyd, Pa. The quartzite is mined by the open pit method and processed in a mill at the mine. The operation regularly produces five standard grades of sand and one grade of crushed stone; however, the company accepts special orders and will produce material to meet the customer's specifications. Beneficiation (chiefly crushing and screening) is controlled by laboratory screen tests on samples taken during preparation of the sand. The chief uses of the sand are for foundry operations, furnace lining, concrete aggregate, and other specialized uses. The quartzite in this deposit is of uniform composition and does not require control by chemical analysis. However, for special purposes, analysis will be furnished.

Jan 1, 1965

By J. Kunze, R. Degal

During the last 100 years, the submerged arc furnace has been one of the most amazing diversified melting units. These furnaces have found their application in more than 20 different main industrial areas such as iron, ferro alloy, chemical industry, lead, zinc, copper, refractory, titanium oxide, recycling, phosphorus etc. Such an evolution was only possible because of tremendous efforts in research and development and due to the large range of design solutions. The worldwide strong competition also forced the industry and plant suppliers to develop highly efficient, economically balanced units in optimized sizes and with long lifetimes, to adapt to the market conditions. Regarding the environment, the plants improved significantly in terms of water treatment plants and off-gas treatments as well as on site recycling units. This paper will give a short overview regarding the history of the furnace and the latest developments in today?s main application fields: ferro alloys, non-ferrous, special application and recycling. In addition new activities in research and developments are briefly discussed.

Jan 1, 2004

By Reno M. Pappas, Christopher Mark

This report presents results of a U.S. Bureau of Mines study of longwall gob material. The objective of this work was to determine material stiffness properties of the gob for use in numerical models of rock mass response to longwall mining. Photographs of actual mine gob were digitized to obtain approximate particle size gradations of gob material. The gradation curve was shifted down to a lab- oratory scale, and 20 uniaxial compression tests were conducted. Varying the maximum particle size was not found to affect the stress-strain behavior, but changing the gradation appeared to influence the stress-strain behavior. The stress-strain relationship of the simulated gob material was nonlinear, the stress-secant-modulus relationship, was approximately linear, and the stress-tangent-modulus relationship was approximately a second-order polynomial function. Equations were generated from these curves, providing numerical modelers with a means to estimate gob moduli based on the stress level. In addition, the experimental data were statistically evaluated using multiple regression analyses, producing a series of equations to predict the secant and tangent moduli from the given stress level, bulking factor, rock strength, and thickness-to-width shape ratio of the particles.

Jan 1, 1993

By R. L. Xu

In this paper, the author would like to point out with figures that the building industry is one of the key industrial sectors of the national economy in China. And in the coming 15 years, the output of building construction will not in the least decrease, but increase. The requirements for building standards, quality, functions as well as physical environment will also be higher along with the incessant development of the national economy and the gradual raising of people's living standard. China is a country with a vast territory and a great, variety of physical characteristics. The topographic and engineering geotechnical conditions are complex and varies considerably from place to place. Although, in recent years, encouraging progress has been made in building construction, there still exist many problems unsolved or even not explored at all, which we have to tackle in the future design and construction of foundations. Also reviewed in this paper are the achievements attained in the past thirty odd years and the challenge we will face in the foundation engineering field in China.

Jan 1, 2010

By R. W. Schutz

"Titanium possesses an exceptional and wide-range resistance to chlorides and their compounds when compared to most corrosion-resistant engineering alloys (CRAs) used in the chemical process industry. This natural resistance to chlorides stems from titanium’s protective, tenacious, and readily rehealable titanium oxide surface film, which is chemically stable over a wide range of pH and redox potentials in aqueous environments. This passive film explains titanium’s elevated resistance to anodic pitting, crevice and stress corrosion, and erosion-corrosion in aqueous chloride environments.Guidelines for successful selection and application of industrial titanium alloys are derived from an extensive laboratory test database and more than forty years of industrial/chemical service experience. These guidelines are simplified, and alloy corrosion performance is assessed with respect to four basic aqueous chloride service categories where selection or consideration of titanium is highly merited. An overview of historical titanium alloy applications in chloride-rich environments in a wide variety of process industries substantiates their exceptional chloride tolerance. These industrial titanium alloys are cost-competitive with stainless steels and nickel alloys, readily commercially available, and routinely fabricated and welded in the shop and field via well-established methods."

Jan 1, 2002

By F. F. Skiba, P. J. Root

A mathematical model has been used to investigate crossflow effects in a stratified reservoir during an idealized displacement process. A process in which one incompressible fluid displaces completely another incompressible fluid of the same density and viscosity was considered. The reservoir was assumed to be composed of homogeneous layers which are discrete but interconnected. Approximate five-spot flow geometry was simulated by arranging two pie-shaped cylindrical (two-dimensional) wedges in series. Some of the common production methods rely, for their effectiveness, on the fact that the formation consists of isolated strata. This is particularly true of selective plugging and single-zone production-injection methods. The effectiveness of these techniques for several cases in which adjacent strata are in communication has been evaluated. The usual production-injection schemes for fluid injection processes involve using the same completion interval in both the production and the injection wells. The efficiency of this, as well as alternative productioz-injection procedures has been examined for some cases involving communicating strata. INTRODUCTION The performance of many fluid injection projects is marred by early breakthrough and by production of a high percentage of the displacing phase after breakthrough. This channeling effect, if it occurs in reservoirs which have large permeability variations, is often explained on the basis of a model composed of discrete, isolated strata. Corrective or preventive measures based on this same model are also common. The behavior of stratified models has been the subject of considerable study. An excellent review of the early literature was given by Seba.1 Studies of the depletion performance have since been made for continuous, unrestricted communication between strata2-4 and for production from one permeable bed in continuous but restricted communication with an adjacent permeable bed.5,6 Model studies of displacement processes in stratified systems with crossflow also have been reprted.7-12 Finally, methods which account for crossflow have been developed for computing displacement behavior in stratified systems.13,14 Most methods for controlling or preventing channeling involve some change in the interval open to production and/or injection. Although many variations of the selective completion problem have been studied in regard to the depletion of a reservoir, little attention has been given to the behavior of a displacement process under similar conditions. Sebal used a resistance network model to study the performance of a process in which one incompressible fluid displaces an identical fluid from a linear, stratified reservoir. He investigated the possibility of improving the vertical coverage by limiting the completion interval of the production well. This investigation deals with techniques in which selective completion of the production and/or the injection wells is used in an attempt to control channeling. At one extreme, selective plugging and single-zone isolation (assuming perfect execution) should be successful if the reservoir is actually made up of independent strata. At the other extreme, they can hardly be expected to be successful if the channeling is caused by a mechanism in which stratification effects are negligible even though there are extreme variations in the formation permeability and/or the injectivity profile of the wells is not uniform. By contrast, it is difficult to anticipate the effect that the amount of communication between the beds of a stratified system will have on the efficiency of selective completion techniques. The objective of this study is the quantitative determination of the effect of communication on the behavior of some particular stratified systems which will at least lead to qualitative conclusions.

Jan 1, 1966

By David Preece

The Thirlmere aqueduct was constructed over 110 years ago to provide water from the Lake District (in the north-west of England) to the city of Manchester some 60 miles (100 km) away. The aqueduct remains, to this day, a key piece of infrastructure in the distribution of raw water in the north-west of England. A short section of the aqueduct was identified as being in poor condition during routine inspections by the owner. Subsequent investigations attributed the conduit damage to the movement of unstable ground over the conduit. Bachy Soletanche Ltd was subsequently appointed to carry out the design and construction of the slope stabilisation works and to undertake repairs inside the damaged conduit. The works were undertaken on an existing slope which, in places stands at a gradient of up to 40º to the horizontal. Strict limitations on plant and equipment were imposed by the client (United Utilities) to ensure that slope and conduit loading and associated vibrations were kept to an absolute minimum during construction. An intensive instrumentation system was installed to monitor surface movements, ground movements at depth, conduit movement and strains across existing planes of weaknesses within the conduit. The solution comprised the installation of spaced piles up-slope and down-slope of the conduit. Restrictions were imposed on the minimum stand-off distance between the outside face of the conduit and the piling works so targeted permeation grouting was undertaken to improve the ?connection? between the conduit and the down-slope piles. The presence of existing sub conduit groundwater flows was suspected and the permeation grouting was focused in areas to minimize disruption to the groundwater regime. The paper presents the basis of the design and highlights the combined construction and instrumentation methods adopted to minimise damage to this valuable asset.

Jan 1, 2011

By S. J. Lötter

Analysis of the major and minor components of raw zircon as well as plasma-dissociated zircon was undertaken using inductively coupled plasma optical emission spectroscopy (ICP-OES). Microwave-assisted acid extraction as well as flux fusion using lithium tetraborate were investigated as digestion methods. Microwave-assisted acid extraction samples were analysed with matrix-matched standards. The most successful microwave-assisted acid extractions yielded 44.3(1), 49.75(7), 78.3(3) and 90.0(7) per cent recovery for Zr, Hf, Al, and Fe respectively using sulphuric acid. In no instance was acid extraction capable of complete digestion of the sample matrix. A standard addition method was applied to the flux-fusion samples due to the high complexity of the sample matrix. Method validation for the flux fusion procedure was performed using the SARM 62 certified reference material (CRM) with acceptable recovery ranges being based on the 95 per cent confidence intervals of the CRM. Successful analyses were achieved for Zr, Hf, and Ti with apparent content of 66(6), 1.7(1) and 0.15(1) per cent respectively.

Jan 1, 2012

By M. King Hubbert

"The present large-scale use of energy and power by the human species represents a unique event in the billions of years of geologic history. Furthermore, in magnitude, most of the development has occurred during the present century. In the United States, the peak in the rate of petroleum production occurred in 1970 and that for natural gas is imminent. The peak in the world production of crude oil is expected to occur at about the year 2000 and that for coal production at about 2150 or 2200. For other sources of energy and power, water power, geothermal power and tidal power are inadequate to replace power from fossil fuels. Nuclear power, based on the breeder reactor and utilizing lowgrade deposits of uranium and thorium, has a larger potential than the fossil fuels, but it also constitutes a large perpetual hazard. The largest source of energy available to the earth is solar radiation. This source has a life-expectancy of a geologic time scale, is nonpolluting and is larger in magnitude than any likely requirements by the human s pecies. In consequence of the large supplies of available energy, the period since 1800 has been one of an unprecedented exponential industrial growth. This also has been accompanied by a world-wide ecological disturbance, including that of the human population. It can easily be seen that such a period of growth must be ephemeral in character and, in fact, is now almost over. One aspect of this transition from a state of exponential growth to a state of nongrowth is the present alarm over an ""energy crisis."" Actually, the world's present problems are by no means unmanageable in terms of present biological and technological knowledge. The real crisis confronting us is, therefore, not an energy crisis but a cultural crisis. During the last two centuries, we have evalved what amounts to an exponential- growth culture, with institutions based on the premise of an indefinite continuation of exponential growth. One of the principal consequences of the cessation of exponential growth will be an inevitable revision of some of the tenets of that culture."

Jan 1, 1973