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The viscosity of high magnesium content FeO-Fe3O4-SiO2-CaO-MgO slags at nickel flash smelting conditions was investigated using a commercial rotational viscometer. The studied parameters were compositions of slag and temperature. The viscosity of these slags was measured as a function of CaO, MgO, SiO2, FeO. Fe3O4 and Fe/SiO2 in temperature range from 1473K to 1723K. These slags contained 5.81 to 10.59 pct MgO, 0 to 10.37 pct CaO, 28.21 to 36.21 pct SiO2, 39.40 to 55.42 pct Fe and 1.1 to 1.5 Fe/SiO2.

Jan 1, 1999

By Mustafa Kumral, Yuksel Asli Sari

Underground mining operations are sensitive to price fluctuations because they usually perform with a narrow profit margin compared to open-pit mining. Furthermore, the economic evaluations regarding operation are based on estimated or simulated grades rather than actual values. These bring a high degree of uncertainty to the viability of an operation. Hence, mine planning that accounts for uncertainty is crucial for underground mining operations. As an underground mining technique, sublevel stoping has geotechnical, curing time, seismicity, cost minimization, and production requirements. A new mixedinteger linear program is proposed that considers the uncertainty associated with net present value using chance-constrained programming. The net present value (NPV) maximization objective is transformed into a multi-objective maximization problem where one objective is to maximize the mean NPV, and the other objective is to maximize the negative standard deviation multiplied by a scalar called risk or reliability level. The balance between the two objectives was maintained by this scalar and was selected based on the reliability level of the project. A case study was conducted with varying reliability levels, and sequences were generated. It was shown that the expected net present value increased at higher reliability levels, and the overall value of the objective function decreased as the reliability level increased. In other words, the variance component penalized the value of the objective function. Moreover, it was observed from the case study that at lower reliability levels, stope grade order bears similarity to the extraction order.

Aug 4, 2023

By Adrian C. Dorenfeld

Concentradora "Dana Aida" (100 t/d capacity) was built in 1971-1972 to treat dumps and ores containing mixed oxide-sulfide copper-gold-silver minerals from two veins. The veins, Don Felipe and aria are about 150 m apart, but are distinctly different mineralogically. The deposit is near San Juan de Guadalupe, Durango. Mexico. All new process equipment was manufactured locally, in or near Torreon, Coahuila. Sampling, ore testing, flowsheet design, plant design, drawings purchasing, financing, etc. was planned and directed by two engineers. Construction was executed by local miners and common labor (largely agricultural). The paper presents detailed costs for equipment and construction. The subsequent breaking-in operation is discussed.

Jan 1, 1979

By Northcutt Ely, Charles F. Wheatley

This chapter deals with the systems of laws by which governments regulate the exploration for and production of the minerals within their jurisdictions. It is a summary, restricted by necessary space limitations, of material assembled by the author for a forthcoming publication of the United States Bureau of Mines, "Summary of Mining and Petroleum Laws of the World." (Information Circular, 1959.) The present study is organized in three parts, dealing with (1) the historical background of these legal systems, (2) laws of the United States, and (3) laws of other countries of the world. The reader's attention is invited to the acknowledgments at the end of the chapter, which inadequately express the appreciation due those who have assisted in the collection of this material. Part I. Historical Development of Major Western Systems of Land Tenancy with Respect to the Ownership and Control of Minerals The use of metals in primitive societies was largely confined to the manufacture of weapons for self-preservation. The ruler's control over copper, then brass, then iron, was essential to maintenance of his own ascendancy at home and his group's position against neighbors who had access to similar metals. Ancient societies were thus characterized by the ruling group's ownership of minerals and metals. The Egyptian civilization, which emerged in the fourth millenium B.C. upon the agricultural subjugation of the lower valley of the Nile, was responsible for extensive development of the upper valley as a source of mineral wealth. The production of gold during the height of that civilization has been estimated at $30,000,000 per year, thus equaling the early placers of California and Australia. The mines of Egypt were the property of the Pharaohs and were controlled at their direction. Greek mining developed a different scheme of land tenancy which more closely resembled modem concepts. Development of mineral resources was

Jan 1, 1959

By P Gomez, R Baumgartner, G Escobar

"The Cerro Corona mine consists of a Cu-Au porphyry deposit located in the Andes of northern Peru. The deposit comprises a typical Cu-Au multiphase porphyry mineralisation that has been overprinted by an epithermal event. This has generated a complex pattern of argillic alteration facies, which was accompanied by a locally structural-controlled Au-Cu mineralisation with the presence of gold and limited Cu sulfides and sulfosalts. These features, along with the porphyry-style mineralisation, produced a multifaceted occurrence of gold.Since the beginning of operations at Cerro Corona in 2008 there has been a continuous improvement of the geological and mineralogical knowledge. All mineralogical studies have mainly focused on host rock types and, to a lesser extent, alteration minerals, but little work has been done on the mineralisation itself. As a consequence, limited mineralogical information was available for use in the process optimisation initiatives.In the last two years, a series of mineralogical characterisation studies were undertaken with two main goals. First, to gain an understanding of the mineralisation genesis and second, to obtain a detailed characterisation of copper and gold minerals to support ongoing process optimisation. The first goal was achieved by conventional optical microscopy while the second required electronic microscopy and other microanalyses due to the necessity of quantifying several minerals of interest for the processing.The results were used to refine pre-existing geometallurgical domains, explain copper and gold losses in the flotation process and to some extent, improve copper and gold recoveries. The mineralogical characterisation is an ongoing work. Mineralogy provides the basis for any optimisation exercise since it looks in detail at the material to be treated and therefore, should be part of all geometallurgical programs.CITATION:Baumgartner, R, Gomez, P and Escobar, G, 2016. Comprehensive Mineralogical Characterisation at the Cerro Corona Cu-Au Porphyry Mine – the Fundamental Key for Geometallurgical Applications, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 221–230 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By W. L. Price

I. INTRODUCTION Today, there are two conflicting trends facing the designer of the bulk material handling system. The first trend is the necessity to stockpile increasingly larger amounts of bulk material (coal, ore, stone etc.) as economically as possible. Fig. 1 illustrates such a typical large storage pile. The second trend is the increasing awareness of the ecological problems of today manifesting itself in a new concern over possible air pollution from storage pile surface particles. The conflict between these two trends can become dramatic when this bulk storage pile is located near a heavily populated area. Strong winds can easily create a severe local problem by blowing the particles from the pile surface toward residential and commercial areas, igniting a crisis in public relations. (2), (3), (4). To help define our combined subject and ecological culprit more accurately, Fig. 2 shows the commonly accepted size range of dust particles. A descrip¬tion of the present state-of-the-art of dust control for large storage piles is the intent of this paper. II. OPEN STORAGE PILE SYSTEMS - ALTERNATE CHOICES AND RELATIVE COSTS In discussing the open storage dust problem and possible solutions, one obvious question arises - what are the economics of placing large bulk storage under cover? Part or this answer will be found in Fig. 3 - an approximate unit capital cost comparison between several methods of storage. It will be noted that the cost curve(s) for the closed concrete silo storage illustrated in Fig. 4 is cheaper per ton at relatively small tonnage capacities, but as tonnage increases, the open pile storage unit cost (B) becomes more economical. Curve (T) covers the cost of open storage using the plow feeder arrangement shown in Fig. 5. A gravity draw-down pile with feeders at the base as shown in Fig. 6 represents yet another open storage choice.

Jan 1, 1972

By D L. Head

Critical risk management (CRM) has become one of the latest safety buzz terms in mining. Everyone seems to be doing it, everyone seems to know about it, yet we are still having fatalities in our industry from well understood hazards such as mobile equipment amongst others.

May 5, 2022

By John C. Edwards

A fire location computational model was developed by the U.S. Bureau of Mines. The model can determine all the possible paths in a mine that smoke can travel from a fixed fire source to a smoke detector. The associated FORTRAN computer program can be utilized to determine the minimum travel time from a source fire to a smoke detector. The difference in travel time from an isolated fire source to two or more detectors can be used to isolate those airways in which the source fire is located.

Jan 1, 1990

By C. L. Severy

The Reeder No. 1 well was drilled by the Bureau of Mines in cooperation with the Geological Survey as agents for the Defense Plant Corporation. The well is south of Crescent Junction near Thompson, Grand County, Utah. It was started May 5, 1942, and completed August 3, 1942, for the purpose of con-firming the presence of magnesium salts in a deeply buried bed. Drilling was done under contract by the Mack Drilling Co. This report contains an outline of the physical features of the well, a brief history of drilling, and a description of the deposits and occurrences of oil and gas encountered in the drill hole. The work performed by the Bureau of Mines is described in considerable detail, with particular emphasis on drilling procedure and sampling. The report is concluded with a brief description of core-sample preparation for analyses. Appendix A comprises a log of the drill hole, and appendix B is a tabulation of analyses of cores.

Jan 1, 1949

By Alex Stewart

Most iron bearing ores treated by the R=N Direct Reduction Process yield products lower in phosphorus than the initial ores. The sulfur is also removed and generally is in the range of 0.02 to 0.05 percent in the final R=N product, independent of the sulfur content of both the ore and carbon fuel used. The mechanism and thermodynamic justification of the principal reactions leading to the removal of both phosphorus and sulfur and the control of sulfur in the iron concentrate produced are discussed and supported by the results of laboratory experiments. In substantially all iron ores (containing up to 4% sulfur as sulfate) and solid carbon fuels (containing sulfur from 1 to 8%) tested, the rejection of sulfur has been in the order of 90-95%, with not more than 0.02 0.05% sulfur in the final metallic iron product. With respect to phosphorus-bearing iron ores ranging up to 0.70% P205, the rejection to tailings has been in the order of 70-95%, resulting in not more than 0.03 - 0.07% phosphorus in the final product.

Jan 1, 1958

By Unkown

To the Membership of the Institute Gentlemen: The Mineral Industry of Canada in 1948 The preliminary estimate issued by the Dominion Bureau of Statistics and tabulated in the Bulletin of January, 1949, indicated that the value of Canada's mineral production in 1948 reached an all-time high of $808,180,216, showing an increase of 25 per cent over the previous record of $644,696,007 established in the preceding year. The output value of metallics was increased by 22.4 per cent; of fuels, by 43.7 percent of other non-metallics, by 19 per 'cent; and of structural materials, by 16.8 per cent. The value of metals produced in 1948 at $483,770,759, was about $87,000,000 more than in the previous year. There were substantial increases in the tonnages of copper, lead zinc nickel, and other base metals produced, but the rises in market prices for such metals accounted for most of the gains in output values. Production of gold at 3,495,403 ounces valued at $122,339,105 indicated an increase in volume of approximately 500,000 ounces and an increase in value of 14 per cent. Despite the benefits provided under the Emergency Gold Mining Assistance Act 1948 the volume of gold produced in the year was still nearly 2,000,000 ounces less than the record of 5,300,000 ounces established in 1941. The value of mineral fuels produced in 1948, at $158,787,255, was 44 per cent above the 1947 total. Coal production at 18,431,250 tons valued at $107,298,757, while substantially higher than in the preceding year was still half a million tons below the record reached in 1942. Striking developments in the Leduc field in Alberta were responsible for bringing the output of crude petroleum in the year to a new high of 12,098,166 barrels, valued at $36,858,959.

Jan 1, 1949

By AIME AIME

A CORPORATION would go into bankruptcy if its affairs were conducted as are those of the state of New York, according to the Committee on New York State Government Reorganization of the American Engineering Council of the Federated American Engineering Societies, in a report to the chairman, of the Joint Judiciary Committees of the Senate and Assembly. The report, just made public, was signed by the three members of the committee who were appointed by Herbert Hoover. They were H. de-B. Parsons, chair- man, Paul G. Brown and Lewis B. Stillwell. Although the American Engineering Council is a national organization, it decided to aid in governmental reorganization in New York State because of the magnitude of the task. The Council's committee in its report urged the passage of three state reorganization amendments for consolidation of departments, an executive budget system, and a four-year term for the higher state officials. In the words of the report :

Jan 1, 1921

By T. I. Urbancic, C-I. Trifu

"ABSTRACTSeveral case studies are presented on the use of seismic techniques to map active structures, evaluate changes in stress levels, and identify the conditions leading to large magnitude seismic events and the generation of rock-bursts in Canadian mines. The results suggest that microseismicity can be used to identify the orientation of active fractures; define regions of relatively high and low stress, and those most likely to host a rockburst; determine the role of local stress on observed shear failures; and identify the path of stress transfer associated with the remote triggering of rockbursts. Additionally, the conditions leading to rock-bursts can be characterized by a significant increase in the clustering of microseismic events along the fault plane orientation of an impending event, and an increase in the effective stress levels. It is concluded that the analysis of microseismicity provides the means for remotely monitoring rock mass behaviour as a result of mining."

Jan 1, 1997

By L Clarkson, D Williams, P Redcliffe, F van der Wal

This research presents a snapshot and insight into the trends, patterns, and common considerations identified in the current standing of real-time tailings dam monitoring practice. Based primarily on information derived from concurrent research by the author (in form of a Catalogue of Real-time Instrumentation and Monitoring Techniques for Tailings Dams), challenges and opportunities when transitioning to a real-time monitoring system are discussed. Learnings and key considerations between different monitoring approaches are explored, including themes of limitations and advantages that were observed consistently through global supplier feedback.

Jul 1, 2021

By Carl R. Peterson

The Rapidex continuous drill and blast tunneling concept utilizes a unique spiral blasting pattern that permits efficient performance with relatively small single shots, while at the same time directing major blast fragments at right angles to the tunnel axis. The concept's self-shielding geometry permits the design of a lightly shielded machine that can stay at the tunnel face firing frequent small blasts to provide rapid, virtually continuous advance. This paper describes Phase III of the development program (supported under Bureau of Mines contract H0252047) in which the "front end" of the machine?drilling loading, and shooting components, together with the shield--was fabricated and field tested underground at the White Pine Copper mine, Michigan. One of the major accomplishments of the Phase III effort was to develop a fully remote controlled loading and initiation system in which explosive slurry is pushed, through a hose into the blasthole by a small water-driven piston carrying the blasting cap. The cap is ignited via an induction coil just prior to entry into the borehole, after which a delay permits complete -withdrawal and shielding of the loading hose. The ultimate objective of the present Bureau-sponsored program is to evaluate the feasibility of mechanizing hard rock mining operations, such as development to a point where drilling, loading, shooting, and mucking can proceed simultaneously and result in increased productivity.

Jan 1, 1977

By D Laskovski, T Nguyen

Flotation surveying can be an extremely powerful means of determining opportunities for circuit optimisation and benchmarking. The type of survey employed depends heavily on the nature of the information required from the survey. It follows then that the type of survey determines the type of samples required; however, regardless of the type, the success or failure of a survey is often dependent on the correct used of appropriate sampling techniques at each sampling point. For a successful flotation plant survey it is vital that the correct samples be collected at the correct time in respect to the feed and each other. This paper discusses the current best practice sampling methods used in flotation surveying and discusses in detail the ideal sample masses based on theoretical analysis. Comparisons with JKTech’s database of real plant operations will then be made.CITATION:Laskovski, D and Nguyen, T, 2014. An investigation of current flotation survey sampling, in Proceedings Sampling 2014 , pp 99–106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By R. W. Gurry

IN the course of a series of measurements of the rate of diffusion of carbon in austenite at about 960°C. (1760°F.) and 1110°C. (2030°F.), it became necessary to determine carbon concentration when austenite is saturated with graphite, because of indications that the hitherto accepted value of the solubility of graphite in this temperature range is too low. Specimens of carbonyl iron were saturated at temperature in a hydrogen-toluene atmosphere which was in equilibrium with graphite. The carbon content of the steel was measured either by combustion or by the loss of weight after substantially complete decarburization in an atmosphere of hydrogen saturated at room temperature with water vapor. The absence of carbide or graphite as a phase at temperature was demonstrated by microscopic examination of saturated specimens that had been drastically quenched. The mean result of concordant measurements is that gamma iron saturated with respect to graphite contains 1.39 per cent carbon at 957°C. (1755°F.) and 1.89 per cent at 1110°C. (2030°F.). These two values, plotted along with what appears from the literature to be the best value (0.69 per cent) at the iron-graphite eutectoid temperature (738°C. or 1360°F.), yield a curve that is almost linear, and which, continued upward through a short interval, leads to a limiting solubility of 1.98 per cent at the iron-graphite eutectic temperature 1135°C. (2075°F.) instead of the commonly accepted value of about 1.7 per cent. EXPERIMENTAL PROCEDURE The samples of carbonyl iron, with the exception of those for microscopic examination, were cylinders 3.8 cm. long, 0.475 cm. in diameter. They were placed in a graphite holder and suspended in a vertical furnace, the temperature of which was controlled precisely by means of the resistance of the platinum winding.1 In the empty furnace the range of temperature over a distance of 4 cm. at the heat center was 9°C. (16°F.) but at a given location the temperature remained within ±0.5°C. (0.9°F.); it was measured by inserting a platinum-rhodium couple calibrated at the melting point of palladium, 1555°C. Since the presence of the sample probably improved the uniformity of temperature, it was decided to consider the average temperature of the sample to be 3°C. lower than the maximum measured in the empty furnace with the same setting of the controller. Data were obtained in the vicinity of two temperatures, 960°C. (1760°F.) and 1110°C. (2030°F.). The samples for microscopic examination, 2.2 cm. long, 0.475 cm. in diameter, were suspended individually on pure iron wire; for these no temperature correction was applied. The carburizing gas passed into the furnace was dry, oxygen-free hydrogen saturated at room temperature with

Jan 1, 1942

By John D. Nelson

Foundation underpinning is a common component of remediation schemes for distressed foundations on expansive soils. For many applications in expansive soil, micropiles have distinct advantages over other techniques. This paper will concentrate on the design and construction of micropiles in expansive soil. It discusses the nature of building distress and the relationship between foundation movement and soil heave. It presents methods for determining the factors that are required for the design of micropiles. Such factors include calculation of expected free-field heave, depth of soil wetting, and prediction of pier movement. A finite element program developed by the authors and others to determine pier heave and internal forces is presented. The input parameters that are required for pier analysis are discussed, and the nature of the output and the sensitivity of the results to the output are described. A case example illustrates the advantages of micropiles over other methods.

Aug 1, 2013

By David V. Ragone, James A. Craig, Richard E. Balzhiser

The Gibbs free energies of formation of UC2 and UC were measured by equilibrating two-phase mixtures of UC2 + C and UC, + UC with liquid bismuth. The measured equilibrium concentrations of uranium in the bismuth combined with available activity coefficient information yielded uranium activities in these two-phase regions. Measurements on UC2 were performed over the range 1015 to 1160 K and on UC over the range 1115° to 1165°K. The values obtained for UC2 are in excellent agveement with values determined using combustton calorimetry and low-temperature heat capacity measurements. The UC values are in fair agreement with the calorimetric values, differing by about 10 pct from the calorimetric determination. MUCH interest has been shown in the uranium carbides in recent years because of their potential as nuclear fuels. As nuclear reactor operating temperatures have been raised to increase thermal efficiency, new fuels have been required. The uranium carbides are of interest because of their high melting points, >2000°C, high thermal conductivity, and resistance to irradiation damage. The manufacture and use of uranium carbides are aided by a knowledge of their stability and reactivity under various conditions. In this regard the thermo-chemical properties of the carbides, i.e., heat capacity, heat of formation, free energy of formation, and so forth, are particularly important. A great amount of work has recently been done on the thermodynamics of the U-C system. Unfortunately, however, there has not been good agreement among the various investigations. This study of the free energies of formation of uranium monocarbide and uranium di-carbide in the temperature region 1100°-1200° K was undertaken to help clarify the situation. It should be noted that in the temperature range of this investigation, 1100°- 1200° K, the thermodynam-ically stable phase in equilibrium with graphite is U2C3, not UC2, Fig. 1. However, U2C3 is reported to be stable only under extremely low oxygen and nitrogen pressure. Although UC2 is metastable below 150O°C, it exists under most experimental conditions. It should also be noted that "UC," never exists as UC2 but with compositions near UC1.9. However, "UC2" will be used to designate the dicarbide phase except when the stoi-chiometry is necessary for clarity. METHOD The approach taken in this study of the free energies of formation of UC and UC2 was to determine the thermo- dynamic activities of uranium in the two-phase regions UC, + C and UC + UC, by equilibrating the two-phase mixtures with the liquid bismuth. When a mixture of solid UC2 + C is brought to equilibrium with liquid bismuth, the reaction that occurs is: Neither carbon nor UC, could be detected as dissolved material in the bismuth. The standard free energy for this reaction may be written: In the two-phase region UC, + C, Fig. 1, the thermo-dynamic activities of UC2 and carbon are unity. The activity of uranium in this region was determined by measuring the concentration of uranium in a liquid bismuth melt in equilibrium with the two-phase mixture. This concentration was then used in conjunction with the activity coefficient data of uranium in bismuth reported by Tien et al.' to determine the activity of uranium in the two-phase region, UC, + C. All of the quantities in Eq. [2] were then known, and the AG; (uc,) was evaluated. UC + UC2. For the studies involving UC + UC,, the reaction taking place when the two-phase mixture is brought to equilibrium with liquid bismuth is: The standard free-energy change for this reaction is given by:

Jan 1, 1969

By Kafui Nyavor

The indirect, and the direct contact mechanisms of bacteria oxidation of sulfides were studied using Thiobacillus ferrooxidans and pyrite. The aim was to determine which of the two generally aeeepted mechanisms played a dominant role, if any, during acid mine drainage (AMD) formation from the oxidation of sulfide minerals. The results show that at a pH of 4.5 where T. ferrooxidans are quite active, but where initial chemical oxidation of pyrite to Fe2+ is limited, the bacteria were unable to directly oxidize pyrite to any significant extent. Whereas, in the presence of Fe2+, T. ferrooxidallS assisted oxidation of pyrite by the indirect mechanism was observed and sustained over the pH and Eb range where the bacteria is active. The results lead to the conclusion that the direct contactmechanism of pyrite oxidition by T. ferrooxidans is insignificant. The predominant, and possibly the only, pathway involves the indirect bacteria oxidation of available Fe2+ to Fe3+, which in turn oxidizes FeS2 to generate additional Fe2+ and acidity in a cyclic process.

Jan 1, 1996