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By J. Espí

The mineral price assigned in mining project design is critical to determining the economic feasibility of a project. Nevertheless, although it is not difficult to find literature about market metal prices, it is much more complicated to achieve a specific methodology for calculating the value or which justifications are appropriate to include. This study presents an analysis of various methods for selecting metal prices and investigates the mechanisms and motives underlying price selections. The results describe various attitudes adopted by the designers of mining investment projects, and how the price can be determined not just by means of forecasting but also by consideration of other relevant parameters.

Aug 1, 2013

By A. D. Hughes

C. W. MERRILL*-Mr. Hughes' paper not only is very well presented but is most timely in that it covers a subject of vital interest to the United States. Tin is one of the strategic metals which has not been found here in appreciable quantities. The total United States tin output since the first recorded production over 100 years ago would not supply current consumption for a fortnight. On the consumption side, tin is extremely important in national defense because of its use in tin plate which, in the form of tin cans, makes it possible to feed properly the armies that the United States recruits from its civilian population in emergencies. Moreover, the internal combustion engines so important in powering tanks, planes, and other war machines, require large quantities of tin alloys for bearings and for soldering. These considerations, along with the fact that Malaya, historically, has been the leading source of tin to the United States, make the kind of information that Mr. Hughes has presented so ably, a matter of vital interest.

Jan 1, 1949

By P Holtham, J Meng, E Tabosa, W Xie

Turbulence and its distribution are of great importance in flotation, and have received considerable attention recently. However, there is no mature technique to measure turbulence in three-phase (liquid-solid-gas) industrial flotation cells due to the opaque, highly aggressive and abrasive nature of the slurry involved. Previous research has shown that the piezoelectric vibration sensor (PVS) is a promising tool for turbulence measurement in industrial flotation cells. The PVS is a robust device that converts mechanical vibration to electrical signal, from which turbulence information can be extracted. An improved calibration method has allowed development of a frequency model to calculate the force applied to the sensor. Experimental results and comparison with laser doppler anemometry (LDA) have shown that the PVS can measure fluid kinetic energy, which is related to turbulent kinetic energy, a parameter used in the literature to represent turbulence in flotation. Laboratory measurement in a two-phase (water and air) 60 L cell and with slurry in a 3.5 L cell gave good stable results and mostly consistent trends between the measured turbulence profile and cell operation. When applied in a 300 m3 industrial cell filled with water, the addition of air or slurry to the cell resulted in a shift in the turbulence profile. This is expected because a change in fluid density will change the force applied to the sensor. It is therefore concluded that the piezoelectric sensor is an easy-to-use and robust technique that is fully capable of measuring turbulence in industrial flotation environments.CITATION:Meng, J, Tabosa, E, Xie, W, Runge, K C and Holtham, P, 2014. Development and application of a piezoelectric sensor for turbulence measurement in industrial flotation cells, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 457–470 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By Goutam H. Shahani

The current economic downturn has been at the center of media attention for several years. Today, the mining and mineral sectors are being impacted by highly fluctuating supply-and-demand conditions, extreme price volatility and tremendous market uncertainty on a world-wide basis. There have been numerous plant closings, project cancellations and employee layoffs. In this gloomy economic environment, it is easy to forget that the world?s gross domestic product (GDP) has more than doubled in real terms during the last 30 years. While current market turbulence may continue for some time, the long-term trend is unmistakably upward. Living standards are rising all over the world, thereby creating demand for food, clothing, transportation and housing. This translates into tremendous demand for the mining and mineral sectors. In the future, new capacity and plant expansions will be necessary to meet this need. These investments, which typically have a life span of 30-plus years, will have to be based on long-term economic considerations rather than current market conditions.

Jan 1, 2011

By R. Mumbi, M. Peart, E. Arinaitwe, B. Mbao, J. Zulu

Since 1925, xanthates have been widely used in sulfide flotation due to their low cost, ease of manufacture, and ability to float most value species. However, the industry's increasing need for safer and more selective alternatives, driven by low head grades, poor-quality, difficult-to-process ore with complex mineralogy, and stricter environmental regulations, has led to the development of Solvay's AERO® XR series of collectors. These custom-formulated products are based on greener chemistries and offer metallurgical benefits that are similar to or better than those of xanthates, without the safety concerns. Developed through Solvay's Flotation Matrix (FM) 100 approach, the XR series collectors are suitable for a wide range of applications, including the processing of Cu, Zn, and Cu-Ni, as well as the flotation of precious metals. This paper will highlight the differences between xanthates and XR series collectors, and present case studies of their successful commercial application at various global operations.

Jan 1, 2023

By F. E. Walker

The Bureau of Mines determined total sulfur and sulfur forms for coal in 283 counties in 29 States and 2 fields of the State of Alaska. Specifically, organic, pyritic, and sulfate sulfur were measured of approximately 2,900 samples, and they include most of the coalbeds in the United States.

Jan 1, 1966

By F. E. Walker

The Bureau of Mines determined total sulfur and sulfur forms for coal in 283 counties in 29 States and 2 fields of the State of Alaska. Specifically, organic, pyritic, and sulfate sulfur were measured of approximately 2,900 samples, and they include most of the coalbeds in the United States.

Jan 1, 1966

The last decade has seen a very rapid development in TBM tunnelling. Some trends are purely technical or economical and others relate more to preferences of different interests. Power levels have more than doubled and thrust levels too. Shield machines are developed to be able to handle harder rock and the open TBMs are made more feasible for `difficult' rock. What is right and what is wrong is more a matter of opinion, but one thing is certain: TBMs now are a useful tool and no longer an experimental work-shop for the enthusiasts.This paper highlights some recent developments and indicates some probable future ones. A few features that have increased the open TBMs' ability to cope with ever harder rock and also to overcome problems with poor rock are discussed in detail, using the Atlas Copco JARVA Mk 27 -the most powerful TBM built so far - as a reference.

Jan 1, 1993

"Above ground, elevated belt conveyors with span >200m between support points can cross valleys, rivers, forests and buildings with minimal footprint. The Cable Bridge Conveyor is a new type of suspension bridge based belt conveyor system that has long span between support points. It combines typical belt conveyor and the improved simple suspension bridge to form a conveyor bridge. The improved simple suspension bridge places a widened bridge deck directly on suspended cables, without the need for high truss towers. The benefits include reduced cost and increase aerodynamic stability compared to conventional suspension bridges. The Cable Bridge Conveyor’s compatibility with current belt conveyors allows the versatility in application. INTRODUCTION Belt conveyor is a ubiquitous material handling system. Conveyors can be placed directly on ground or elevated above ground by support structures. Considerations of cost, design, environment, civil work, safety and process requirements are all factors in choosing the ground based or elevated conveyors (1). The ground based conveyor has the lowest structural cost, where the conveyor is laying on an existing road. Maintenance access is easy and straight forward. Compared to the ground based conveyor, the elevated conveyor can cross existing buildings and structures, give passage to traffic beneath the conveyor, has smaller footprint, and requires less civil work to pass mountainous areas. The drawback of the elevated conveyor is higher structural cost, which can be compared with savings in civil work and other benefits. Conventional elevated conveyors are supported by rigid truss type structures, with typical span of 15m to 25m between concrete support bents or steel trestles. Triangular truss, using steel pipes instead of hot rolled steel sections, is more efficient. The typical span of triangular truss supported conveyor is around 30m to 40m, while the weight is about 10% less than conventional box truss with shorter span (2). Long span elevated structure based on suspension bridge is another step forward in increasing the distance between support bents, reaching 100m~400m and beyond. The very wide distance between support points of an elevated conveyor offers unique benefits. The conveyor can cross rivers, valleys, highways, forests and other obstacles with minimal footprint and reduced civil work. The versatility from long span conveyors makes bulk material transportation over previously impossible terrains now a feasible option."

Jan 1, 2015

By D. G. Champion

"A comparison of diesel engine power ratings with in-service capability, and the selection of unit size and total number of units are discussed in the paper. Engine specific fuel consumption and its evaluation in relation to manufacturers' tolerances and equipment load factors is reviewed along with the suitable plant layout. The potential for heat recovery is discussed in connection with simple and operable recovery systems f or exhaust and cooling circuits. Maintenance standards as related to improved reliability and reduced fuel and operating costs are also outlined. IntroductionDiesel generators are used in Canadian mining operations to provide electrical power for "" base- load"" requirements in some instances and for ""stand-by"" or ""emergency"" power in almost every producing mine in the country . There are over 300 mines in Canada of which only a handful have to generate their own electricity. Only one or two mine s enjoy access to a hydroelectric site. Consequently, the diesel engine is the principal prime mover because of its high efficiency relative to other prime movers in the size range in question.The author has been associated with several “base-load” plants in addition to participation in numerous projects requiring emergency diesel generators. Records indicate that engine performance in term s of reliability and efficiency lags behind other industries where the diesel engine is used more extensively, such as the shipping industry which is able to make a more prudent selection of original equipment and enjoy easy access to highly skilled operating and maintenance personnel. It is hoped that the contents of this paper will be of value to Canadian operators of diesel generators, in the generation of prime power or applications for back-up power."

Jan 1, 1986

By M. Kawata, T. Amano, T. Miyamoto, K. Shibayama

"The High Pressure Acid Leach (HPAL) plant of Taganito HPAL Nickel Corporation (THPAL), located in Taganito, Philippines, with a nameplate capacity of 30,000 Ni-t/year started commercial operation on October 2013. The plant load was smoothly ramped up and it achieved monthly production equivalent to 33,000 Ni-t/year in 2016. Partial improvement of the plant capacity for the achievement of 36,000 Ni-t/year, as evaluated from the current operation progress of each system is planned for 2017. In this paper, aside from presenting the progress of the plant ramp-up, research and development activities such as the reduction of nickel loss and the improvement of filtration capacity which was achieved by particle size control of ZnS precipitates in the Zinc Removal system are also discussed.INTRODUCTION Taganito HPAL Plant Project History of THPAL Taganito HPAL Nickel Corporation (THPAL) was incorporated in August 2008, as a joint venture of three (3) companies, namely Mitsui Corporation with 15% share, Nickel Asia Corporation (NAC) with 10% share and Sumitomo Metal Mining Corporation (SMM) with a controlling stake of 75%. Aside from its capital share, NAC’s Taganito Mining Corporation (TMC) supplies the ore for the HPAL plant located in Taganito, Claver, Mindanao, Philippines. The objective of THPAL is to produce 30,000 MT of nickel and 2,600 MT of cobalt as mixed (Ni/Co) sulfide by treating nickel laterite ore in the Philippines and exporting to Japan as raw material for SMM’s Niihama Nickel Refinery (NNR) for the next 30 years. In other words, 1.15 wt% of nickel in ore is refined to 99.99 wt% nickel in electrolytic nickel. The mixed (Ni/Co) sulfide is shipped to NNR and SMM provides the technology and management personnel to THPAL plant as well as sulfuric acid which is the main reagent for HPAL process. Figure 1 shows the location of THPAL and current relationship between the stake holders.The Characteristics of THPAL Plant In terms of plant design, a 2-train system is applied for the HPAL circuit considering the reliability of the process, facility and avoidance of whole plant shutdown due to HPAL troubles. The technical data, operation know-how and improvements gained from the successful operation of Coral Bay Nickel Corporation (CBNC) which was established in April 2002 were reflected in THPAL’s plant design. As for the H2S plant, a more economical design was considered which is different from CBNC."

Jan 1, 2017

By Young W. A.

The Eagle Silver mine is in the Rush Valley mining district, Tooele County, Utah, and is now operated by the Hampton Mining Co. The property, originally referred to as the Argent, is reported to have been one of the first discoveries in the district. The early operators mined ore to a depth of 850 feet, at which point the property was abandoned because of excessive water. During 1905 the Honerine tunnel was driven into the area approximately 1,800 feet below the collar of the Argent shaft. This tunnel served to drain the levels above and operations were resumed. Ore deposits in the Eagle Silver mine occur in the Galena King lime-stone, a 20-to 60-foot member of interbedded quartzite and limestone in the Oquirrh formation of Pennsylvanian age. This member has been faulted along the bedding, forming the Galena King gouge. Mineralization commonly occurs in or near this gouge area in a brecciated, highly altered, pipelike zone. The known ore shoots occur in association with the breccia pipe, commonly adjacent to cross faulting and porphyry intrusions. In general, two ore shoots have been mined on the upper levels of the mine, one lying to the east and the other to the west of the breccia zone. The Bureau of Mines diamond-drilling program was begun during the latter part of 1948 and completed early in 1949. Nine holes were drilled, aggregating 852.8 feet. Sludge and core samples from mineralized sections were analyzed in the Salt Lake City laboratories. A total of 87 sludge, 71 core, and 11 chip samples was submitted for analysis.

Jan 1, 1950

By J. M. Whatley

"IntroductionIN UNDERGROUND mining operations, the mine hoist has become one of the most important and one of the most expensive single pieces of equipment. As the means of transporting men and materials to the face, broken ore to the mill, and waste to the dump, it is often the very lifeline of a mine and must operate with dependability and efficiency or the whole operation will suffer. The mine hoist has become synonymous with safety. In few other types of mechanical equipment do so many men so frequently and completely place their lives. In Canada, more has probably been done to assure safe hoisting than in most other countries, but, unfortunately, this has resulted, in many cases, in the mines having to pay a high price for equipment. Hoist manufacturers have carried out much research in recent years in the endeavour to keep down these costs and at the same time maintain or improve the efficiency and safety of their products. Broadly classified, the bases for design research are dependability, efficiency, safety, and first cost.Probably the greatest single factor influencing the design of mine hoists was the introduction of electric motor drives. It was not until about 1905 that an effective start was made in the development of electric mine hoists, and then only with machines of small size. From that time on, however, progress was rapid, as may be gauged from the fact that by 1910 one large group of mines in Johannesburg had in use, or on order, fifty-four three-phase hoists and four Ward-Leonard. type hoists."

Jan 1, 1953

By Valeh Aghazadeh, Shima Barakan, Mina Soleymani, Ehsan Bidari, Morovvat Faridazad

Molybdenite is the most important molybdenum concentrate, which is mainly recovered as a by-product from porphyry copper deposits. Due to the low efficiency of purification processes such as flotation in the reduction of copper content of molybdenum concentrate to a standard level (i.e., less than 0.5 wt.%), further purification by a hydrometallurgical method is required. Although different types of chemical reagents were found to be effective in the leaching of copper minerals from molybdenum concentrate, the mechanisms of these processes remain largely unexplored. In this study, optimal conditions for maximum copper leaching (> 99%) were obtained at the concentration of HCl = 1 M, FeCl3 = 0.5 M, CuCl2 = 0.05 M, CaCl2 = 0.5 M at 75 °C, 500 rpm, and S:L = 1:10 during 60 min. CuCl2 was identified as the most effective leaching reagent for copper dissolution in agreement with Visual MINTEQ model results due to the formation of various types of copper chloride complexes. Furthermore, the electrochemical behaviors of FeCl3, CuCl2, and CaCl2 reagents before and after the leaching process were investigated by the cyclic voltammetry technique. The results of cyclic voltammograms at different scan rates verified the presence of copper chloride complexes, and ferric ions as the oxidizing reagents for better dissolution of copper sulfides. Based on kinetic study results of shrinking core models, both chemical and diffusion reactions controlled the copper leaching process with an obtained activation energy of 33.56 kJ/mol. For recovery of the leached copper, the precipitation process was done by the addition of Na2S at 45 °C, S/Cu = 1, and pH = 9.

Dec 26, 2022

By S. F. Mauser

This report describes the study of factors which affect medium voltage (661 - 1000 volts) trailing cable splices used in underground coal mines. Improvements in quality, dependability, and design of splice kits and shop splices are presented in the study results and recommended guidelines and regulations. Recommended research programs are included which describe approaches for development of the recommended guidelines and regulations for medium voltage trailing cable splices. The basis for the conclusions and recommendations presented in this report is included in three appendices which describe a survey, splice examination, and general requirements development prepared during the progress of this study.

Jan 1, 1977

By R. J. Leary

A small electronic digital computer employing punched cards has been used to facilitate the solution of a variety of problems in Bureau of Mines pyrometallurgical research. In this work the computer has been found to be economical for solving both simple problems that occur repeatedly and those involving complex or iterative calculations. Each of these classes of problems and their respective solutions are described. These small computers can be used effectively by researchers when they work in consultation with a computer specialist. Close team work produces the required solutions in less time, and, oftentimes, in a more useful form. Participation in programming by researchers develops in them a skill for evaluating the suitability of problems for electronic computing.

Jan 1, 1960

By John Shirokoff, Ladan Khaksar

"Cyclic polarization technique and also potentiodynamic measurements were applied to study corrosion behavior of 13% chromium steels in chloride containing environment. Potentiodynamic measurements were performed at 25 and 75 °C with 0, 10 and 20 g/l NaCl in 0.01 M hydrochloric acid solution. At the same time, the significant pitting parameters such as corrosion potential (Ecorr), pitting potential (Epit), protection potential (Epro) and passive current (Ipass) of cyclic polarization curves with various NaCl concentration were analyzed and compared to describe the corrosion behavior of 13% chromium stainless steel. Surface measurement techniques such as SEM and EDS were used for morphology and analysis of corrosion products. The results showed that both temperature and Cl- concentration had significant effects on corrosion behavior of 13% chromium stainless steel in acidic solution.INTRODUCTION Of all the corrosion resistant alloys (CRA) used in oil and gas developments, martensitic stainless steels (MSS) are some of the most common ones these days. These steels not only have the advantages of normal steels: high strength, cost-effective, easy to manufacture, available in a wide variety of product forms, but they also have good CO2 corrosion resistance at higher temperatures as a result of their 11% minimum chromium content. One of the most common types of MSS used in the oil and gas industry is 13% chromium steel. NACE and API standards both reference several different varieties of 13% chromium steels for use in oil and gas projects(“Corrosion Resistant High Cr Steel for Oil and Gas Wells,” 2013). All types of 13% chromium steels have about 12 to 14% chromium and other minor alloying additions, and can be placed into two general groups: conventional and modified. Conventional 13% Cr steels (13Cr) are those most common in oil and gas, some of which are CA6NM (UNS J91150), AISI 410(UNS S41000), and AISI 420 (UNS S42000). These alloys have excellent corrosion resistance when compared to carbon steels up to about 300°F (150°C) and are used for a variety of wellhead, tubular, and downhole components however they have very limited resistance to cracking in H2S (Vallourec Group, 2015). Modified 13% Cr (M13Cr) steels came from the need for increased corrosion resistance at higher temperatures, increased H2S cracking resistance, and increased yield strength above 85 ksi (586 Mpa) primarily for tubular goods and other downhole equipment. These features were developed by taking a conventional 13Cr steel and adding nickel (Ni), molybdenum (Mo), copper (Cu), and other alloying elements. M13Cr provides better corrosion resistance than 13Cr up to about 350°F (177°C), yield strengths up to 110 ksi (758 Mpa), and also improved H2S cracking resistance(“Corrosion Resistant High Cr Steel for Oil and Gas Wells,” 2013)."

Jan 1, 2017

By Aníbal Gatañaga Coll

Dada la peligrosidad del sílice libre como principal problema en el campo de la higiene industrial, el objetivo del trabajo es controlar y evaluar la concentración de dichos polvos a través del uso de tres métodos: El método químico, el de difracción de rayos X y el petrográfico. El primero (N. A. Talvitie), utiliza un reactivo que descompone y disuelve a todos los constituyentes de la muestra, excepto al cuarzo, quedando calcinado y filtrado; el segundo método es eficaz, pero requiere de un equipo muy costoso, mientras que el método petrográfico muestra una mejor identificación de los minerales, determinando las cualidades de los materiales que se producen en la composición del polvo, así como precisa la pequeñez de las partículas encontradas en los polvos industriales y sobre todo de la capacidad del operador.

Jul 20, 1955

By Johne Jesus Mol Peixoto

No reator RH, a otimização do fluxo recirculatório de aço entre a câmara de vácuo e a panela é a chave para promover as reações de refino. Neste trabalho, foram utilizados água e solução de cloreto de zinco (ZnCl2) como fluido similar ao aço para investigar a taxa de circulação no modelo a frio de um reator RH em escala 1:7,5. A taxa de circulação foi determinada utilizando o método de pontes de Strain Gages. A técnica PIV foi utilizada de modo a calibrar e validar os resultados. O aumento da vazão de gás de 30l/min para 120l/min resultou na elevação da taxa de circulação para ambos os fluidos. Cálculos preliminares demonstraram que há grande diferença nas condições de arraste de escória entre os sistemas água/óleo e ZnCl2/óleo.

Aug 17, 2017

By M. Kim, M. Ha

"The effect of red mud on the melting behavior of ferronickel slag was investigated by a laboratory-scale horizontal tube furnace. Melting and softening of slag samples fluxed with different amount of red mud was examined by in-situ visualization technique at temperature range from 1400 to 1550°C. FactSageTM 7.0 was used for the thermodynamic calculation of multi component system of ferronickel slag and red mud. Liquid phase area was extended to lower temperature by adding red mud indicating its suitability as a flux material. X-ray diffraction analysis confirmed the dependency of the phase changes on the red mud content. Microscopic observation by scanning electron microscope (SEM / EDX) clarified the phase transformations from olivine to spinel along with red mud additions.INTRODUCTION Ferronickel smelting by submerged arc furnace (SAF) is an energy intensive process performed at high temperature range 1500–1600°C. During the smelting process of saprolitic nickel laterite ore with a nickel content of 2.2–2.3 pct, a large quantity of ferronickel slag is being produced that account for 97 pct of ore charged. To achieve ferronickel grade of 15–20 pct Ni, electrical energy of 80 to 85 MW is used for the melting and reduction of nickel oxide (NiO) and iron oxide (FeO) in the ore (Rodd et al., 2010). Unreduced components, mostly MgO, SiO2 and partly FeO are removed from the furnace in a liquid slag form by a tapping operation. Due to the high melting temperature, forsterite (Mg2SiO4) based slag containing approximately 10 pct FeO requires typical process temperature of 1600°C. Flux in metallurgical process is a medium that decreases melting and operating temperatures while it increases fluidity of the liquid slags. Calcite and fluorite are examples of flux materials used for the ironmaking, steel refining and continuous casting process. Oxide systems based on CaO - CaF2 - SiO2 - Al2O3 - MgO cover most of the slag composition in ferrous metallurgy accordingly. Crucial operating factors for ironmaking and steelmaking slags are basicity (typically CaO/SiO2 ratio), viscosity and impurity levels. These are extensively controlled by the fluxes. General metallurgical fluxes such as limestone, dolomite and calcium fluoride are abundant in nature and supplied to steel mills at low prices. Meanwhile, in copper flash smelting process, silica is supplied with copper concentrate to remove iron oxide (FeO) generated from sulfide oxidation. FeO - SiO2 binary system formulates eutectic area at 25–38 pct of silica that has low melting temperature below 1205°C. Fayalitic system (Fe2SiO4) that has low viscosity (0.1 Pa·s) (Park et al., 2011) facilitates easy separation of slags from molten sulfide mattes. Recently, copper plants actively utilize recycled raw materials as a flux. Various recycled glasses are ground and fed to copper smelting process as a partial replacement of silica ore. Applying industrial wastes to smelting processes is advantageous since the operators can reduce the production cost remarkably. Not to mention the consumption of recycled materials can ultimately minimize the environmental risks and the waste management costs. The authors, therefore, investigated the reasonable waste materials that can be effectively used for ferronickel smelting process. Prerequisites for potential fluxing materials are non-recyclable property, low transportation cost and excellent performance as a flux."

Jan 1, 2017