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By Everett P. Partridge, J. E. Conley

Available statistics show that the demands of the American chemical industry for sodium sulphate have been increasing slightly in recent years. The supply from domestic sources, particularly in the form of byproduct salt cake from the acid manufacturers, has been tending to decrease this to the growing manufacture of synthetic acid. Both hydrochloric and nitric acids are being synthesized from their elements. The natural result has been that a smaller amount of salt cake is available. Simultaneously, the expansion of the kraft-paper industry, especially in the South, has brought about greater demand for sodium sulphate in that section. This demand is being met by domestic byproduct salt cake, by imported German sodium sulphate made from potash waste liquors, and by favorably situated domestic deposits of Glauber salts and the anhydrous salt, thenardite. No shortage of natural sodium sulphate exists in the United States, but usually such deposits occur in semiarid regions far removed from transportation facilities and from markets. Moreover, the major portion of the natural deposits is Glauber salt or mirabilite (Na2 504 • 10H20), which must be dried or dehydrated in order to meet consumer requirements. The water of hydration represents, roughly, 55 percent of the total weight of the crude salts and therefore has a very important influence on transportation costs, in many instances the cost of getting even the dehydrated product to market is the deciding economic factor. Therefore, the recovery of production of anhydrous sodium sulphate from plant-waste liquors or from natural brines of suitable composition might be economically feasible.

Mar 1, 1936

By Gandhi

Piled raft foundation under uniformly distributed vertical loads has been analyzed using Finite Element Method. The soil is considered to be linear elastic, isotropic, homogeneous. The raft,pile and the soil have been idealized with eight noded brick elements. Parametric study have been carried out varying pile length, soil modulus, raft thickness, and pile spacing. Design charts have been produced to achieve 50% load sharing between pile and raft for optimum design. Data available in literature is compared with the design chart results and found satisfactory.

Jan 1, 1996

By Rethel L. Hubbard

Fourteen straight-run asphalts were prepared in the laboratory from bitumens obtained from three sources: (1) native bitumen from Rozel Point, Utah, (2). bitumen extracted from Athabaska bituminous sandstone at Canada, and (3) bitumen extracted from Edna bituminous sandstone outcropping in San Luis Obispo County, to seven asphalts with penetrations ranging from 19 to 287 at 77 F. were prepared from each of the bitumens. The yields of the prepared asphalts ranged from 74.5 percent for a 27-penetration asphalt from the Athabaska bitumen to 99.5 percent for a 271-penetration asphalt from the Rozel Point bitumen.

Jan 1, 1949

By D A. Edmunds

The most important development that has been taking place recently relating to mining operations in New Zealand would generally be regarded as being the Resource Management Law Reform. This has been widely publicised by the Government as a comprehensive review of the laws governing New Zealand's natural and physical resources. Submissions have been sought and a free phone provided to encourage public participation. Recently a Discussion Paper has been prepared by the Core Group coordinating the review to explain progress on Phase One (Ministry for the Environment, Directions for Change: A Discussion Paper, Wellington 1988). It outlines Government decisions already taken which impinge on the Review and describes the possible models for resource management laws. However, it is possible that some fundamental practical issues of significance to the mining industry will not be addressed and may be lost sight of in the much wider issues which are to be covered. The purpose of our paper is to address one of these issues namely, the interrelationship between any new resource management legislation and the Conservation Act 1987 (as recently amended) in the context of Ministerial consents. The importance of this issue can be seen from the fact that as at 7 June 1988 there were 279 mining licence applications and 223 prospecting licence applications waiting to be determined by the Minister of Conservation. Since April 1987 only 19 mining and 13 prospecting licences have been consented to. In addition a major proportion of New Zealand's mineral resources are contained with land administered by the Department.

Jan 1, 1988

By G. H. Charlewood, J. W. McBean

"One hundred years after being developed, the diamond drill is still an essential tool in mineral exploration. The basic principle is unchanged, but the technique has been revolutionized, particularly in the past fifteen years. The cost of core drilling has not kept pace with the rising cost of living. The price of machinery, supplies and labour in drilling has doubled and trebled since 1946. Some of the techniques which have made it possible to hold the price line are described."

Jan 1, 1967

By M. W. Wadsley

"Physical and chemical property models are widely used in process engineering. There exist, in the published literature, completely empirical models of ''thermodynamic properties"", that is, property models that are not consistent with the laws of thermodynamics. There also exist property models that purport to be thermodynamically consistent but are flawed in their implementation. There are also published property models that are consistent with the laws of thermodynamics but that do not reproduce property values with an acceptable accuracy. A practicing engineer might be asked to assess very different property models for which there are a variety of claims. This paper discusses features of thermodynamic and empirical property models that may assist in their practical evaluation and implementation."

Jan 1, 2005

By Lloyd A. Morley

This final report concludes the documentation under Grant G0155003 and details research not covered under foregoing report volumes. The first chapter lists all other reports. The following chapters are divided into three major research tasks: Continuous Safety Monitoring Systems, Battery and Battery-charging Safety, and Mine Power System Transients. The monitoring chapter discusses the prediction of power-system failures. The battery chapter details work on battery-box stresses, battery chargers, and the elimination of electrocutions. The final chapter covers transient instrumentation, distribution transients sources and suppression, and utilization transients on mine power systems.

Jan 1, 1981

By Paul J. Sabatini, Yazen A. Khasawneh

"A Demag CC1800 crawler crane was partially erected on crane mats adjacent to a seawall when settlements near a corner of the crane mat area were observed to be slightly larger than previously assessed. A ground improvement program including installation of dry soil cement mix (DSM) piers was implemented to improve soil bearing capacity. Due to near-surface obstructions, only 75 percent of the DSM piers were installed to the design depth. Because of the partial installation of the DSM piers, an evaluation of the crane pad stability and the effect of the crane loading on the stability of an adjacent 10-ft high concrete seawall, which was believed to have limited (if any) reserve capacity, was required. A two-dimensional finite element model was developed to evaluate the responses of the partially improved ground and the sea wall to the loads imposed by the crane. Geotechnical site investigation and laboratory testing programs were performed to better define the subsurface conditions near the area where settlements occurred and to provide the required mechanical parameters for the soil constitutive model. Analysis results indicate that total and differential settlements of the crane pad and the increase in load on the seawall were tolerable provided limited excavation and replacement of weak dredged soils outside the DSM area would be implemented.INTRODUCTION & BACKGROUNDA Demag CC1800 was erected on 8 ft × 16 ft crane lattice mats at about 12 ft from an existing seawall. Approximately 3.5 in. of subsidence was observed at one corner of the crane mats, while the crane was partially erected and stationary. The approximate location of the crane mats with respect to the existing seawall when the subsidence occurred is shown on Fig. 1.The seawall consists of a reinforced concrete wall connected by reinforced concrete bents to a composite section of sheet pile wall; the total depth of the seawall is about 29 ft. The bents are spaced at about 20’4” and supported by five piles at each bent location. The composite sheet pile consists of concrete and a sheet pile section with a reinforced concrete wale section. The retaining wall is about 10 ft in height and is supported at three levels. The first support level comprises a 2-½” diameter steel rod near the top of the wall spaced at 40’8” the second and third level supports comprise 1-½” diameter steel rods spaced at about 5’6”. The second level support is inclined at about 10 degrees below horizontal and the third level support is oriented horizontally through the wall footing. A schematic of the seawall section is shown on Fig. 2.A geotechnical site investigation was implemented soon after the subsidence was observed. The program included advancing four borings to a depth ranging from 16 ft below ground surface (bgs) to about 30 ft bgs. In general, the investigation showed sandy material (likely fill that was used behind the retaining wall) from the ground surface in two borings located immediately behind the retaining wall. The other two borings furthest from the retaining wall showed very soft to soft clay (possibly dredged material) from the ground surface to a depth of about 10 ft bgs. Based on this information, the ultimate bearing capacity of the subsoils was estimated to range from 1,200 to 2,000 pounds per square feet (psf). From the anticipated crane loading (weight of the crane and loading lifts), a minimum allowable bearing capacity of about 1,500 psf would be required for safe operation. To achieve the required bearing capacity a ground improvement program was selected and implemented."

Jan 1, 2017

By Susanne Hering, Brent Kirby, Charles D. Litton, Tracy Allen, Kirk R. Smith, Rufus Edwards

In developing countries, high levels of particle pollution from the use of coal and biomass fuels for household cooking and heating are a major cause of ill health and premature mortality. The cost and complexity of existing monitoring equipment, combined with the need to sample many locations, make routine quantification of household particle pollution levels difficult. Recent advances in technology, however, have enabled the development of a small, portable, data-logging particle monitor modified from commercial smoke alarm technology that can meet the needs of surveys in the developing world at reasonable cost. Laboratory comparisons of a prototype particle monitor developed at the University of California at Berkeley (UCB) with gravimetric filters, a tapered element oscillating microbalance, and a TSI DustTrak to quantify the UCB particle monitor response as a function of both concentration and particle size and to examine sensor response in relation to changes in temperature, relative humidity, and elevation are presented here. UCB particle monitors showed good linearity in response to different concentrations of laboratory-generated oleic acid aerosols with a coarse (mass median diameter, 2.1 µm) and fine (mass median diameter, 0.27-0.42 µm) size distributions (average r2 = 0.997 ± 0.005). The photoelectric and ionization chamber showed a wide range of responses based on particle size and, thus, require calibration with the aerosol of interest. The ionization chamber was five times more sensitive to fine rather than coarse particles, whereas the photoelectric chamber was five times more sensitive to coarse than fine. The ratio of the response between the two sensors has the potential for mass calibration of individual data points based on estimated parameters of the size distribution. The results demonstrate the significant potential of this monitor, which will facilitate the evaluation of interventions (improved fuels, stoves, and ventilation) on indoor air pollution levels and research on the impacts of indoor particle levels on health in developing countries.

By T. F. Mitchell, J. V. Batty, R. R. Wells, R. Havens

"INTRODUCTION )ne of the most important wartime activities of the Bureau of Mines was the search for new sources of minerals necessary to the prosecution of the war. As a part of the investigation of strategic mineral deposits in the United States under the Strategic Minerals Act (Public 117, 76th Cong., 1st Sess., Ch. 190), examining engineers of the Bureau of Mines investigated and sampled various deposits of chrome ore in California, Idaho, Montana, Oregon, and Washington, and those deposits that warranted further study were explored by diamond drilling, trenching, and drifting, as re¬quired. During these investigations, samples were submitted to the Ore Dressing Section of the Salt Lake City Station for metallurgical testing. This paper gives data summarizing results obtained from laboratory ore-dressing studies of the chrome ores submitted.Although the deposits range widely in geographical location, the mineral occurrence of all of them is strikingly similar. Chromium, in all of the ores tested, is present as impure chromite or chromium spinel. Although pure chromite (FeCr204 or FeO.Cr203) contains 68 percent chromic oxide, the iron may be replaced in varying amounts of magnesium, and the chromium may be replaced similarly by aluminum and ferric iron. In studying concentration methods as applied to chrome ores, the composition of the chrome mineral is of fundamental importance, because it is manifestly impossible to produce a high-chrome concentrate from a low-chrome chromite by any mechanical process.In all but one of the ores, the gangue material consists of olivine or altered olivine minerals such as serpentine, antigorite, and chrysotile. The exception, the Antelope or from Montana, has a gangue chiefly composed of actinolite, chlorite, and talc."

Jun 1, 1947

By E. Marcoux, F. Lotfi, A. Belkabir, L. Maacha, A. C. Brown, S. Brunet

"Koudiat Aïcha is a small Zn-Pb-Cu deposit, enclosed in the Visean Sarhlef volcano-sedimentary series of the Moroccan Hercynian Jebilet massif. Base metal mineralization is located between a basal unit consisting of black argillite with arenite intercalations, and an upper unit composed of black argillite with locally fossiliferous calcareous units towards the top. Paraconcordant gabbro sills are present in both the upper and basal units, and the enclosing strata. Three successive phases of deformation linked to regional deformation overprint the volcano-sedimentary rocks and gabbros, as well as the sulfide mineralization.The mineral deposit includes several lenses of massive to semimassive pyrrhotite, 1 to 20 m thick, with a large halo of disseminated sulfide veinlets and sulfide nodules within a zone of intense chlorite alteration in the footwall. The ore mineralogy consists of massive to semimassive pyrrhotite with lesser amounts of sphalerite, chalcopyrite, arsenopyrite, galena, pyrite, and stannite.Lead isotope results (206Pb/204Pb averaging 18.27) suggest that the metals of the Koudiat Aïcha deposit are derived from the volcano-sedimentary host rocks. Sulfur isotopes also indicate a volcano-sedimentary origin, with bacterial reduction of sulfate (d34SCDT = -7.5‰ to -10.5‰). The conditions for sulfide meta-morphic equilibration range from 250° to 330°C (sphalerite and chlorite geothermometers). The gabbroic sills could have been a local heat source for hydrothermal circulation. Based on these geological and mineralogical features, a Besshi-type model seems appropriate for the genesis of the Koudiat Aïcha mineralization.Koudiat Aïcha est un petit dépôt de Zn-Pb-Cu, encaissé dans la série volcano-sédimentaire Viséenne de Sarhlef dans le massif Hercynien de Jebilet au Maroc. La minéralisation en métaux usuels se situe entre une unité basale d’argilite noire interlitée d’arénite et une unité supérieure composée d’argilite noire comprenant localement des calcaires fossilifères près de son sommet. Des sills de gabbro paraconcordants sont présent à la fois dans les unités basale et supérieure, ainsi que dans les strates environnantes. Trois phases de déformation successives associées a la déformation régionale superposent leurs effets sur les roches volcano-sédimentaires, les gabbros, ainsi que la minéralisation sulfurée. Ce gîte comprend plusieurs lentilles de pyrrhotite massive a semimassive de 1 a 20 m d’épaisseur au sein d’un large halo de veinules de sulfures disséminés et en nodules au sein d’une zone intensément chloritisée dans le mur du gisement. Le minerai consiste en pyrrhotite massive à semimassive avec des quantités subordonnées de sphalérite, de chalcopyrite, d’arsénopyrite, de galène, de pyrite, et de stannite. Les résultats de l’analyse des isotopes du plomb (206Pb/204Pb moyen de 18.27) suggèrent que les métaux du gîte Koudiat Aïcha proviennent des roches volcano-sédimentaires encaissantes. Les isotopes du souf¬fre indiquent eux-aussi une origine volcano-sédimentaire, impliquant la réduction bactérienne des sulfates (d34SCDT = -7.5‰ et -10.5‰). L’équilibration métamorphique des sulfures s’est produite entre 250° et 330°C (géothermomètres à sphalérite et chlorite). Les sills de gabbro pourraient avoir été la source de chaleur locale responsable de la circulation hydrothermale. Sur la base de ces caractéristiques géologiques et minéralogiques, il semble approprié d’invoquer un modèle de type pour Besshi pour expliquer la genèse de la minéralisation de Koudiat Aïcha."

Jan 1, 2008

By L. M. Lowe, D. G. Feasby, J. R. Goode

"Rare earth resources usually contain minor amounts of radioactive elements. The most widely recognised sources of radioactivity are associated with thorium and uranium. However, also present in the resources are isotopes of rare earth elements (REE) that are themselves radioactive, including lanthanum (La-138), lutetium (Lu-176) and samarium (Sm-147). These radioisotopes, as well as remnants of the natural thorium (Th-232) and uranium (U-238, U-235) decay series, can contribute to significant levels of radioactivity in mixed REE concentrates and in separated products. Levels such as these can present challenges for transport, transboundary movement, product storage, workers’ health and safety, as well as waste management issues at the facilities that separate out the individual REE’s. These are discussed in this paper. A particularly challenging radioactive isotope is Ac-227 (a decay product in the U-235 decay series). Actinium behaves chemically similar to lanthanides and hence normally concentrates with REE multi-element composites. Reliable analysis of Ac-227 is not widely available and the methodology required to deal with this challenge is briefly described. A principle reason for minimization of radioactive content throughout REE processing is restrictive specifications by concentrate purchasers in order to reduce waste management challenges. Approaches to the minimization of radioisotope content in REE concentrates and separated products are outlined in this paper."

Jan 1, 2014

By D A. Vogel

"Sampling may be mandatory for safety or environmental reasons. It may be because the value of a sale needs to be determined or to provide important data for investments. Whatever the reason, an incorrect sample will come at a risk. Only the person that relies on sampling data can imagine what the potential cost of such risk is.Sampling itself has a cost too; the direct cost of a quality control department and indirect cost for interrupting a process, such as stopping a conveyor belt during loading. If all material is the same then only one small sample is enough. But if all the material is different, then a very large sample must be tested; in the conveyor belt scenario it must be stopped very frequently and the associated cost will be high.A good sampling plan finds the proper balance between risk and cost. A good sample must be small enough to handle yet large enough to be representative for what information is required. All good samples have three things in common: there was proper access to the material the sampling tool allowed equal probability of particles being selected nothing was disregarded, everything was included.This too is the core of Gy’s ideal sampling scenario, where all particles have the same probability of being selected and included in the sample. There is risk of bias when part of a lot is excluded from the sample. Extra care is needed when sampling particularly heterogeneous, segregated or layered materials. The sampling tool should never systematically leave out a portion; it shall not push aside large or hard particles. Wet samples shall not stick to the sampling tool. This extends to sample preparation too when reducing particle size and dividing the sample in the process.CITATION:Vogel, D A, 2017. Access, select, include – a review of the commercial sampling of traded bulk commodities in the context of Gy’s Theory of Sampling, in Proceedings Eighth World Conference on Sampling and Blending, pp 367–378 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 9, 2017

By C. J. Newman, R. J. St. Eloi, G. Macfarlane

"The Kidd Creek copper smelter has been expanded from its original design of59000 tonnes of copper per year to over 120 000 tonnes per year. Modifications to the process gas handling system and acid plant have been made to accommodate this higher production rate and, generally, to optimize the operation.The gas handling system associated with the continuous smelting process is discussed in terms of boiler accretions and modifications to minimize their impact on operations; design changes to effect reductions in high pressure drop duct configurations; material changes to overcome corrosion and plant additions to improve gas cleaning capability. The acid plant is reviewed with references to changes made to accommodate the increased S02 gas strength resulting from the higher smelting rates. IntroductionThe Kidd Creek Division of Falconbridge Limited is a base-metal mining and metallurgical complex located in Timmins, Ontario. The discovery of the original copper-zinc-silver orebody was announced in April 1964. Mining operations began in 1966 with a 9000 tonnes per day (t/d) concentrator corning on stream in November of that year. In April 1972, a 108 000 tonnes per year zinc plant was conunissioned. Over the years the facilities have been expanded, such that the concentrator now has the capacity to process 13 000 t/d of ore. To expand zinc production, the world's second installation of the Commco/Sherritt pressure leaching facility was completed in 1983 to bring total zinc production capacity to 136 000 tonnes per year. In 1973, serious planning for a smelter operation began. In early 1975, after studying both continuous smelting and flash smelting processes, a decision was made to proceed with the technology offered by Mitsubishi Metal Corporation of Japan. The Mitsubishi Continuous Smelting Process was to be used for the smelter and the Onahama No. 3 tankhouse technology for the copper refinery."

Jan 1, 1994

Development of Technology for Complex Uranium Ores Processing on the Flotation Process Basis

Sep 13, 2010

Paper written on project work carried out in partial fulfilment of B. Eng (Mining Engineering) degree The stability of a ferrosilicon dense medium suspension is one of the most important parameters to keep under control since it determines the density gradient of the medium in the separation zone and thus directly influences separation sharpness. The stability of ferrosilicon suspensions were characterized using settling tests employing a differential pressure method. Particles smaller than 45 µm and especially the ore fines played an important role in the settling behaviour of the solids. High medium stability is favoured by ore fines, fine medium particles, and high medium densities. Keywords: dense media, ferrosilicon, dense medium stability, ore fines

Jan 1, 2002

By Diana K. Schimmelpfennig

Assessment of revegetation success on mined lands is a difficult, time consuming task and has been the subject of a number of controversies. Present regulations require that both plant cover and aboveground plant biomass be measured for use in making that assessment. Of these two variables, biomass is the most time consuming to measure and requires destructive sampling, a most undesirable requirement on fragile, recently revegetated areas. On the other hand, plant cover can be estimated using the point-frame method which is relatively nondestructive. In addition, vegetation can be sampled more uniformly with the point frame and in less time if species composition measures are to be made. A study was done to evaluate the predictability of aboveground biomass production on revegetated mined sites and adjacent native prairies using plant cover estimates made with the point frame method. The predictability of biomass production by cover estimates bears on the need for both measurements in assessing revegetation success. In general, a positive, statistically, significant correlation was demonstrated between plant cover (estimated by the point frame) and aboveground biomass (estimated by the harvest method) regardless of community type (mined or native), species composition, diversity or level of biomass production. However, the latter did have their effects on the relationship and must be accounted for in any predictive equations (that is to say, the predictive equations must be considered site-specific). Considering the relationship observed between the two parameters, cover estimation may be a sufficient indicator of revegetation success, especially where time and minimization of disturbance are critical.

Jan 1, 1982

By İbrahim Gunes, ATILA GURHAN CELIK, Eren Komurlu

This study introduces a new apparatus designed to improve the load-bearing capacities and insertion efficiency of split set type friction bolts. Laboratory and site studies demonstrated the apparatus’s advantages in terms of practicality and prevention of buckling. The apparatus temporarily compresses the split tubes, reducing friction during insertion and increasing normal stresses and friction capacity at the bolt-rock contacts.

Jan 3, 2022

By Ali Porbaha

Rapid growth in the urban development requires continuous search for innovative technologies to construct complex infrastructure systems. Deep mixing is one promising construction technology that has a wide spectrum of applications for development and expansion of complex urban facilities. Large number of reported case history of the projects in Europe, Japan, and the US demonstrate the versatility of the technology compared to conventional methods of ground modification. A large number of factors influence the quality of the soil cement columns; some of these are rooted in the installation process and the effective use of machinery during construction. This paper attempts to present some issues related to installation of deep mixing that affect quality of the treated columns. Presented here are various installation patterns, installation machinery, installation sequence, effect of penetration/withdrawal injection methods, penetration/withdrawal speed, effect of number of shafts, rotation of the blade, shape and orientation of mixing tools, and rotational speed of the shaft on quality of the treated ground.

Jan 1, 2001

Operational effectiveness is fundamental to any operation, becoming highly topical in those experiencing less than optimal output from their fleets. It is all encompassing aiming to identify those factors that could be improved within production and suggesting solutions in order to optimise the existing fleet and obtain the greatest capital return on expenditure.Argyle Diamond Mine (ADM) is a large open cut diamond mine located in the East Kimberley region of Western Australia, approximately 180 km south of Kununurra. It is owned and operated by Rio Tinto on a two week on/two week off roster fly-in/fly-out from Perth or drive in/drive out from Kununurra. Through benchmarking the operation between January and June 2002, a study was undertaken allowing identification of areas falling below target. Following this, analysis of annualised hours and production downtimes were undertaken to quantify the potential gains of improvements in these areas. Strategies were then identified as stated in the 2002 mine plan, in operational effectiveness meetings, and by staff members. This project aimed to maximise direct working hours through determination of the main issues hindering performance. External and internal factors were considered and a continuous improvement program (CIP) was developed. The CIP aimed at internal site-based improvement teams to identify and implement solutions for improvement on a day-to-day basis.

Jan 1, 2003