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By E. Asselin

Passivation of Fe-Ni-Co alloys during the Caron leach process is thought to result in low cobalt recoveries in ammoniacal ammonium carbonate solutions. A brief review of the available thermochemical data for the (Fe, Ni, Co)-NH3-H2O systems has been undertaken. The stability of the Co(II) and Co(III), Ni(II) and Fe(II) ammines was examined through the use of speciation and Pourbaix diagrams at 298 and 333 K and at 6 M total ammonia. Increasing the temperature reduces the stability fields of the ammines and generally constrains the thermodynamic window for the leach. The Fe(II) ammines are only thermodynamically stable under reducing conditions. Polarization experiments show that these ammines are unlikely to form if oxygen is present. Fe-Ni-Co alloy passivation may be alleviated by careful management of potential.

Nov 1, 2011

By E. Asselin

Passivation of Fe-Ni-Co alloys during the Caron leach process is thought to result in low cobalt recoveries in ammoniacal ammonium carbonate solutions. A brief review of the available thermochemical data for the (Fe, Ni, Co)-NH3-H2O systems has been undertaken. The stability of the Co(II) and Co(III), Ni(II) and Fe(II) am-mines was examined through the use of speciation and Pourbaix diagrams at 298 and 333 K and at 6 M total ammonia. Increasing the temperature reduces the stability fields of the ammines and generally constrains the thermodynamic window for the leach. The Fe(II) ammines are only thermodynamically stable under reducing conditions. Polarization experiments show that these ammines are unlikely to form if oxygen is present. Fe-Ni-Co alloy passivation may be alleviated by careful management of potential.

Jan 1, 2011

By J. M. Marek

The determination of the proper cutoff grade for an open pit metal mine is based on economic criteria and the operating philosophy of the mining company. Previous papers have dealt with the balance of a fixed mine production capacity versus economic return. Mine production capacity is often controlled by the amount of mining equipment and the working area in the pit. A complete cutoff grade strategy is a balance of economic return of mining higher grade material versus the capital costs of additional production capacity and the operating cost of moving the waste and low grade material to assure proper ore release. An approach to the problem is presented which is based in part on work by previous authors and provides guidelines to proper cutoff grade strategy encompassing the time value of money and variable commodity prices.

Jan 1, 1985

By Iga Trisnawati, Fitria Puspita, Himawan Tri Bayu Murti Petrus, Gyan Prameswara, Idi Amin, Andi Nurfaadhilah Ulfah

Laterite ores, rich in essential metals like nickel, iron and cobalt, are a crucial resource for modern technology. However, the extraction of nickel from laterite ores is a complex process due to their intricate mineral compositions and low nickel concentrations. This paper presents the results of a study to understand the leaching behavior of preroasted laterite ore and the impact of roasting on leaching kinetics. The ore was subjected to roasting at 280 and 610 °C for a duration of three hours, followed by leaching in sulfuric acid (H2SO4) under atmospheric conditions. The results show that preroasting the ore at 610 °C significantly improved the recovery of nickel during leaching, with recovery rate of up to 93 percent, and the leaching process of the preroasted ore was primarily controlled by diffusion through the ash layer. The activation energy values were found to be 20.97 kJ/mol for the ore roasted at 280 °C, and 18.97 kJ/mol for the ore roasted at 610°C. These findings suggest that preroasting can enhance the leaching performance of laterite ore, potentially paving the way for more efficient and sustainable nickel extraction processes.

Aug 1, 2024

By Henri Letient, Tom Aley, David Evans

Antamina is a large open-pit copper and zinc mine located within the Central Andes of Northern Peru at an altitude of 4300 masl. The facilities are situated within the headwaters of several watersheds, within the Amazon basin. Nearby villages rely heavily on springs and streams for drinking and irrigation water. The principle source of baseflow during the dry season is from Cretaceous karstic limestone aquifers. Antamina will produce nearly 1.4 billion tonnes of waste rock over its mine life. Finding suitable sites for storing large volumes of waste rock is often a challenging task – especially in karstic, alpine terrain. Detailed hydrogeological investigations are essential for delineating the karstic hydrogeologic watersheds associated with the proposed waste facilities, which are often very different than topographic (hydrologic) watersheds. Contamination vulnerability mapping at Antamina consisted of geological and karst mapping, geophysical surveys, geochemical testing, dye-tracer studies, drilling and aquifer testing. Detailed mapping followed by dye-tracer studies proved to be the most cost-effective methods for characterizing the karst aquifer systems. The results were used to optimize waste rock management at the site to minimize potential impacts on groundwater resources.

Jan 1, 2005

By B. Yarar

The critical surface tension of wetting (?c) of Cu2S, FeS2, PbS, and MoS2 were determined by plotting flotation recovery versus YLV which was arranged by methanol, and Extra-polating to % R = 0. ?c values ranged from 26 dyne cm-1 for MoS2 to 49 dyne cm-1 for PbS and elemental sulfur gave a value of 31.5 dyne cm-1. Minerals exhibiting natural flotability of different extents, could be separated from their mixtures in the absence of conventional flotation reagents, but controlled ?LV. Correlations between non-stoichiometry and degree of natural hydrophobicity for MOS2 are also reported in this paper.

Jan 1, 1983

By F. W. Schweitzer

The trend toward development of large low grade ore bodies has accelerated in recent years. It has been estimated within the copper industry that "porphyry" type deposits will provide the bulk of copper production during the next 30 years. It is further estimated that in these deposits the average ore grade by the year 2000 will be 0.25% copper (1). Many of the new porphyry copper discoveries are of such extremely low grade that they are particularly sensitive to small fluctuations in cost variables and copper prices. Because haulage constitutes a major item of surface mining expense, the capability to transport large tonnages of material at increasingly lower unit costs is vital to the profitable operation of many of these mines. High capacity conveyor belts appear to have considerable promise in this area. The heaviest use of high tonnage conveyors has been in the brown coal industry in Germany. In the past 20 years several such installations have proven successful. In addition to the German installations, several other successful systems have been put into operation. Some examples are: The Oroville Dam project in the United States; the tar sand operation in Northwest Canada; the pre-mine stripping and mining of the Twin Buttes Mine in the United States; the Kursk Magnetite 'dine in the U.S.S.R.; and the Nchanga Copper Mine in Zambia. Most of the systems mentioned are handling alluvial material consisting mainly of fines. The noteworthy point regarding these installations is their high continuous capacity. One of the largest lignite mines in the world is at Fortuna, Germany, where over 15,700 tons (15,250mt) per hour of overburden is transported on an 87 inch (221cm) wide belt running, at over 1000 feet (305m) per minute.(2). Another example is a 20,000 ton (18,150mt) per hour system for loading iron ore into barges on the Great Lakes (3).

Jan 1, 1976

By Robert T. DeGavre

I have been asked by the Society of Mining Engineers to present a paper on Inco Limited's Indonesian nickel project as a case study in the financing of large overseas mining projects. I welcome this opportunity It is a story worth telling not only because the project itself represents a significant human achievement but also because there are certain important lessons that can be derived from our experience in financing the project. The paper will be divided into four sections: (i) a brief history of the project, (ii) a critical appraisal of the project's financing plan in terms of the goals that we sought to achieve, (iii) some comments on certain factors underlying the relative success of the financing plan, and (iv) the contributions that the engineering staffs must make to a successful financing plan. The paper will not present a technical assessment of the project since Inco Limited has been asked to submit a series of papers on this subject at the International Laterite Symposium as part of the 108th Annual Meeting of the AIME in February 1979.

Jan 1, 1978

By Richard Newcomb, Michael Rieber, William A. Vogely

INTRODUCTION The solid fossil and nuclear fuels, but especially uranium, are given prominent, indeed leading, roles by energy experts in most long range estimates of world energy futures. Optimistic forecasts are inspired partly by the disproportionately large solid fuels resource base compared to present rates of consumption or to oil and gas resources, and partly by the vision of inexpensive high technology applications. Such a view overlooks the fact that while resource- use disparities and new technologies give allure to the promise of the solid fuels, they do not guarantee cheap solutions to the basic problems of solid fuel uses: viz., their relatively difficult conditions for efficient ignition and control, including the management of environmentally acceptable residuals disposal. Contrary to the varied versions of this optimistic hypothesis, this paper shows that a great many persistent economic and technical problems interfere with such a simple inference. These act as constraints which qualify or dispute much of the national energy policy based on existing modeling of solid fuel requirements and optimistic engineering evaluations. The assumptions and techniques of such exercises are sometimes at fault. As often as not, however, the distortions created in open market fuel com- petition due to misdirected national energy policies themselves are to blame for misdirected efforts. A number of interesting implications result. Among them are the distinct possibility that the low technology applications will dominate, so that more direct coal and less synfuel or nuclear use will occur; that, accordingly, exhaustion rates for uranium will be low, that the most extensive growth of solid fuel through 2000 will be in conventional pulverized coal cumbustors, and that the traded share of the world coal bum will be much larger than predicted. These trends will place much more pressure on oil and gas prices than forecast by most experts. On the way to these findings the paper demonstrates that solid fuel resource adequacy in situ, balanced against the projections of demands as capacity requirements, mean little as conventionally measured by years to exhaustion or potential supply schedules. Indeed, all stock concepts of demand requirements or of fuel re- sources must be tied to the paths of the unit costs and the deliverable prices of all substitute fuels and systems over time. This requires a dynamic analysis of supply and demand, integrated with geological and engineering constraints, to provide insights into the multiple modes of market and product substitution. Market forces rather than technical promise will determine the allocation of the solid fuels. Moreover, the equilibrium paths of individual fuel prices and market shares are not easily simulated by general or network models, and decision makers will continue to rely on the partial, local comparison of alternatives in their choices of fuel systems at any time. 'The economics of the solid fuels differs from that of other energy sources in important ways relating to their form in use, conversion efficiency, (dis)economies and externalities. Petroleum and gas are in a more convenient form for

Jan 1, 1985

By J. Ke

Traditional geostatistical methods have been used in ore reserve estimation for decades. Neural Networks (NNs) have provided an alternative approach to data analysis and ore reserve estimation. Unlike the traditional geostatistical methods, neural network uses a highly non-linear complex algorithm to do the estimation. Although Neural Networks have been demonstrated to be attractive alternatives as with every new techniques, there are questions which remain unanswered. This paper presents a comparative analysis with different types of metamodeling approaches -- Triangular, Kriging, Spline, and Neural Network. The neural-network is organized in a multiple-layers and Back-propagation model is used to handle the non-linearity and hidden slabs for smoothing the predicted results. With multiple dimensional and very noisy drill hole sample data, the ore grade is predicted and the overall performance is validated by the analysis of R-squared (R2), Root-Mean-Squared (RMS), and contours of ore grade spatial variability. The ore grade and tonnage of estimated outputs are also compared with various cut-off grades.

Jan 1, 2003

By J. B. Hiskey

Of the halogens, the gold iodide complexes are the most stable in aqueous solutions. A series of experiments were performed to investigate the kinetics and mechanism of the leaching reaction between gold and iodide. Using a rotation disk technique, the effects of rotation speed, iodide and iodine concentration, temperature, pH and in the presence of different electrolytes were measured. Oxygen and hydrogen peroxide were also examined as oxidants in the iodide system. The first order reaction rate was found with respect to 13 and half order reaction rate with respect to 1-. The comparison of gold leaching between iodide and cyanide is also presented, in which a rate constant of about 2.6x10-9 mol/cm2? sec for 10-2 M I- and 5x10-3 M I2 was obtained. This value is close to that -for typical cyanidation. Cyclic voltammetry experiments were also performed to examine the electrochemical nature of the reaction which will be presented in part II of this study.

Jan 1, 1990

By E. W. Davis

This paper deals with the role of the Maintenance Department in a milling operation; specifically, the Mines Development, Inc., processing plant at Edgement, South Dakota. The goal of very maintenance department is the smooth and uninterrupted operation of the plant it serves, To achieve this goal, maintenance men adapt various features and procedures into a program designed to fit the characteristics of their particular plant operation. A few of the basic elements of a sound maintenance program are: 1, A periodic preventive maintenance schedule. 2, A systematic inspection and lubrication procedure. 3. A training program for maintenance personnel. 4 A good equipment-history file system, 5. A carefully planned spare parts inventory.

Jan 1, 1962

By Eric Lutz

"Great effort has been expended for more than 40 years to improve the workplace safety and health of surface and underground miners across the United States. When looking at the past decade, withstanding the 2010, Upper Big Branch (UBB) disaster that took the lives of 29 miners, this effort has resulted in a generally decreasing trend from 57 fatalities (22 coal; 35 metal/non-metal) in 2005, to 45 (16 coal; 29 m/ nm) in 2014. Through August of this year, there have been 23 mining-related deaths (eight coal; 15 m/nm). These results reflect continued diligence and perseverance on the part of miners that stay true to our legacy; and demonstrate significant investments from mine-site leadership, mining corporations, and state and federal regulators. However, over the past five years there have been an average of 32 fatalities per year, with a low of 36 (2011 and 2012) to a high of 45 (2014). If we know that there will be somewhere between 30 and 50 mining related deaths next year, which of us will volunteer to be counted as one of the numbered? Clearly, we all agree that one fatality is too many; and as evidenced by changes following UBB, deaths in any sector are deaths reflective of all mining across all sectors.The impact of each miner death touches us all. Miner’s deaths are felt deeply by family and friends, most significantly the children; their communities in which they served, supported, and worshiped; and by society that has lost a hardworking, dependable contributor. Further, to take a slightly cynical, but realistic view, miner fatality events impact the financial vitality of mining and contracting companies and broadly diminish investor confidence. Just as important, these events significantly impact our communities and result in negative public perceptions, which ultimately drive regulatory policy and related compliance pressures. This resulting pressure forces operations to broadly address safety and health gaps in very specific ways (i.e., see U.S. Mine Safety and Health Administration (MSHA) regulations regarding lids for trash cans) minimizing a mine site’s opportunities for operational flexibility. To break this cycle that is the operational reality, mining companies are focusing tremendous efforts on fatality prevention and specifically on dedicated investment to prevent multiple fatality events."

Jan 1, 2015

By S. S. Peng

In dealing with the mining engineering problems, the traditional approaches of laboratory experimental simulations and/or analytical solutions are not very effective. Mainly because the field problems are too complex to be solved with a few simplified assumptions. Conversely it is also true that the experimental and analytical/ numerical models currently available are far from being able to model the actual cases. Under such conditions, the most effective mean of research into mining engineering problems is to combine the mine (field) investigations with laboratory and / or analytical modelings. It is with this concept in mind this research was initiated in 1973. 'The field investigations which began in the fall of 1978 consisted of mainly visiting the mines where surface subsidence monitorings had been or were being monitored and/or surface structural changes had occurred. From such visits, subsidence data were collected. A quick analysis of those data provided preliminary understandings of the characteristics of the surface subsidence parameters in the regions (1-5). Using those date, models of various types are being developed for subsidence prediction / control. So far, a total of 44 longwall subsidence profiles in 22 longwall panels and 10 room-and-pillar profiles in 5 room and-pillar sections have been collected. This paper summarizes the combined results published previously (1-5) and present the preliminary results of the predictive models developed.

Jan 1, 1982

By Janet Briggs, Michael Vertes, J. F. Shirley, R. E. Cutherbertson, Alexander Sutulov, J. D. Vincent

Molybdenum, the 42nd element in the periodic table, is now a very important metal in industry of the United States and the world. Chemically, it is a very complex element having valences of 0, +2, +3, +4, +5, and +6, and can exist as a mixture of these valences in many compounds. It was discovered and separated by Scheele in 1778. At the present time, molybdenite is the only important commercial source of molybdenum. Molybdenum occurs in some 12-14 different recognized minerals, but practically all of the production is molybde¬nite. As late as 1915, it was considered a rare metal. Germany made extensive use of it during the first world war, which resulted in the establishment of a molybdenum industry in the United States at Cli¬max, Colo., in 1917. It was not until the mid-1920s when its introduc¬tion to steelmaking developed for the US automobile industry that the metal gained important acceptance. The first notable example was the Willis-Saint Claire automobile introduced in 1921 by C. Harold Willis, formerly chief metallurgist for Ford Motor Co. Molybdenum has also been produced in the US from wulfenite (PbMoO4) from Arizona and Nevada, and a small amount of molyb¬denite was produced up to the early 1970s as a coproduct from two molybdenum-bismuth mines in Quebec, Canada. The first byproduct production of molybdenite from a copper con¬centrating operation was achieved at Cananea, Sonora, Mexico, and was followed shortly by the Utah division of Kennecott Copper Co. in the mid-1930s. This section of the Handbook is divided into four main subdivi¬sions: Chapter 2, which deals with the concentration and recovery of molybdenite from primary molybdenum ores; Chapter 3, which deals with the recovery and separation of molybdenite as a byproduct from copper production; Chapter 4, which deals with the conversion practices employed for converting molybdenite to the oxide or metal form; and Chapter 5, which covers the uses of molybdenum in steel¬making, chemicals, pigments, lubrication, catalysts, etc. The Free World molybdenum production, for the past eight years from all sources, is shown in Table 1. 2. Primary Molybdenite Ores General In 1978 there were four primary molybdenite recovery plants in operation: Climax, Endako, Quests, and Henderson. For over half a century the Climax mine has been by far the largest and most important source of molybdenum in the world. During the early 1970s a few primary molybdenite mines in British Columbia were shut down due to adverse economical conditions. The largest of these was British Columbia Molybdenum, formerly owned by Kennecott Copper Corp. The Climax plant and operations are described in detail and the opera¬tions of the other plants are summarized following a general discussion of recovering molybdenite from primarily molybdenite ores. Recovery of molybdenite as a byproduct will be taken up in Chapter 3. Geology Molybdenite production from mines in which it is the sole or preponderantly important mineral is confined to ore bodies in granites or igneous-type rocks or pegmatite dikes. More than one state of mineralization is sometimes present as at Climax, York, Hardy, and Questa. In the case of Climax, important byproduct recovery of tung¬sten, tin, pyrite, and monazite is also attained. The molybdenite is commonly disseminated very finely in the siliceous granitic gangue but does occur in stringers and blebs in silicified mineral solution channels. Treatment of Primary Molybdenum Ores All primary molybdenum ores are low in molybdenite, the content ranging from less than 0.20% MoS2 to a high of about 0.40% MoS2. A high resistance to grinding is a common ore characteristic combined with a habit of very fine dissemination of molybdenite in the siliceous portion of the ore. Because of low MoS2 content, high hardness, and fine dissemination of molybdenite in primary ores, it has been necessary to develop a special mill treatment which yields an accepta¬ble recovery at a reasonably low milling cost. Essentially, the treatment consists of intensive rougher flotation at a relatively coarse grind with production of a low grade rougher froth containing a substantial percentage of the molybdenite in the form of low grade middling particles, followed with multistage regrinding to liberate the locked molybdenite and several stages of flotation cleaning to produce a finished grade concentrate. Rougher flotation on pulp ground to ap¬proximately 35 mesh is common practice, even if complete liberation of molybdenite from siliceous gangue may require regrinding to 200 mesh. The flotation of middling particles with a very low content of molybdenite in the rougher flotation step has been made possible by the application of a combination of reagents first developed at the Climax mill and used with some modification in the treatment of all primary molybdenum ores. The reagents commonly employed and their functions in flotation are:

Jan 1, 1985

By Terence P. McNulty

Gold-bearing outcrops were discovered in 1862 by Union soldiers garrisoned at Needles, CA, near the northwest corner of the future State of Arizona. Sporadic mining began several years later, but engineered shaft sinking and mill construction were not adopted at Oatman and the neighboring camp of Goldroad until about 1900. Geological interpretations in 1915 enabled major production during the next decade. In the late-1930s, USSR&M built a new mine and mill in Gold Road and the District flourished until closure by Federal Order L-208 in October 1942. For about a decade, Oatman’s mines were among the largest gold producers in the American West.

Feb 1, 2024

By Edwin H. McKee

Eruption of rhyolitic ash-flow tuffs in the area of the McDermitt (Cordero) caldera began about 17.4 m.y. ago and continued for about 1.5 m.y. During this period of silicic eruptions, a circular area about 30 km in diameter collapsed to form a caldera that subsequently filled with sedimentary and volcanic rocks. 3 A total of more than 200 km of silicic rocks was erupted from the volcano. The final phase of igneous activity, about 15.5 m.y. ago, included resurgent doming and intrusion in the central part of the caldera. Three to 4 m.y. later +I2 m.y. ago), hydrothermal solutions using the northern part of the caldera ring fractures as conduits deposited cinnabar, pyrite, alunite, and other minerals in tuffaceous lake beds and volcanic rocks accumulated within the caldera. The ore-forming solutions may have been a residuum from the silicic magma or connate water or ground water heated by the still-hot resurgent magma in the central part of the caldera. The source of the mercury has not been identified. Later oxidation of the sulfide minerals and redistribution of the supergene minerals corderoite, several mercury nitro-oxychlorides, marcasite, iron, and titanium oxides in the sedimentary rocks account for most of the newly discovered ore body at Cordero.

Jan 1, 1976

By James J. Guesk, Robert W. Reisinger, Timothy C. Richmond

A high-altitude (2,900 m [9,500 ft]) historic underground copper mine in Wyoming is discharging copper-laden water with a neutral pH into an otherwise pristine creek. The Wyoming Abandoned Mine Land program is reclaiming the site under a CERCLA deferral agreement. The clean-up goal is to reduce copper in the mine discharge so that the creek can eventually support a trout fishery. A pilot-scale passive treatment test utilizing sulfate-reducing bacteria has been conducted at the site beginning in summer 1997. Test results show significant reduction in copper concentrations in near-freezing mine water at flow rates ranging to 19 liters per minute (5 gpm)

Jan 1, 2000

By W. L. Wilson

This article could be entitled "The Rediscovery of the Windfall Mine," since it was originally discovered early in this century. The "Rediscovery" was made by personnel of Idaho Mining Corp. during the course of an investigation of the Windfall mine beginning in 1967. There had been historic production from the Windfall mine sporadically from 1908 until 1951 and there was present during much of this time a mill that vat leached crushed ore. Mining was underground to a depth of 91 m (300 ft). Prior to Idaho's activities, the mine had been inactive since the early 1950s. Idaho Mining Corp. was an "exploration company," privately owned and based in Reno, NV. The writer was at that time manager of exploration for Idaho Mining. The company held interests in the Cortez Gold mine, then being readied for production, and had conducted exploration for various mineral commodities in Nevada for several years. Idaho's attention was first directed to the Windfall mine in the Eureka District, Eureka County, Nevada (see Fig. 1, Nevada map) by a search of published geologic literature of the state of Nevada. An attempt was made to acquire a library consisting of all of the published geo-data for the state of Nevada as well as to obtain as much of the unpublished material as could be acquired. A study of these data, and in particular Tom Nolan's Professional Paper 406 (1962), indicated that the Windfall mine was anomalous for the Eureka District in that it contained deposits of disseminated gold. This source and other sources indicated that the Windfall had produced from underground operations approximately 59 kt (65,000 tons) grading 12.6 g/t (0.368 oz per ton) gold ore that was processed in a vat leaching operation and that the gold was "invisible" to the naked eye and could not be panned. It was ascertained that there were no active operations near the mine and a geologic reconnaissance was made and a few samples were taken to attempt to determine if the mineralization was indeed disseminated. The initial group of samples around the mine area averaged 1.25 ppm [11.5 g/t gold (0.036 oz per ton)] and the mineralization did appear to disseminate into the wallrock. The next step involved researching the ownership of property in the immediate area of the mine, and [ ] a property map was constructed that showed six or seven different ownerships of patented and unpatented claims, as well as some open ground, in the target area. Negotiations were commenced with the claim owners, ultimately resulting in the acquisition of all of the desired property, although some of

Jan 1, 1990

By Edward C. Dowling

Froth flotation has been used industrially for many years to separate valuable minerals from their associated gangue constituents. Notwithstanding the significance of this process to the mineral industry, many of the engineering tools needed for the evaluation of the flotation process are still in a developmental stage. Traditionally, the evaluation of a flotation test on both the laboratory and industrial scale has been based largely on a rougher recovery value achieved at a sufficiently long time to give a "final" or "equilibrium" recovery value. The assumption of a time equivalency for a given recovery value between various flotation tests or between laboratory tests and industrial operation underlies this method of evaluation. Such an assumption implies that flotation is an "equilibrium engineering process" and that the time-rate recovery of material from the flotation cell is not affected by changes in the flotation system. It has been shown by Bushell (1) and by Klimpel (2) that the assumption of time equivalency between various flotation tests is unjustified. Consequently, better tools are needed for evaluating flotation test results, Because mathematical flotation models which incorporate both a recovery and a rate function can completely describe flotation time-recovery profiles, they can provide an excellent tool to evaluate flotation tests.

Jan 1, 1984