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By N. Iverson, E. Haft, V. T. McLemore, M. Woodard, E. Owen

Present and emerging technologies are renewing interest in domestic rare earth elements (REE) production. REE deposits throughout the North American Cordilleran alkaline-igneous belt are being re-examined for their economic potential. In New Mexico, the mineral deposits found in this belt are associated with Eocene–Oligocene alkaline to calc-alkaline igneous rocks. Four areas in New Mexico have been examined for their REE potential. The chondrite-normalized REE patterns are similar for all four districts, even though different REE minerals are found. Crandallite, xenotime, bastnäsite and brookite are found in fluorite veins and carbonatites at Laughlin Peak. Bastnäsite was extracted during fluorite processing from 1954-1980 from the Gallinas Mountains, where samples as high as 8% total REE are found in fluorite veins. Other REE minerals include agardite, parasite, xenotime, and monazite. Allanite, thorite and as much as 8133 ppm total REE are found in fluorite veins in the Capitan Mountains. In the Cornudas Mountains, exploration along the outer edge of the Wind Mountain nepheline syenite laccolith and within phonolite dikes, plugs, skarns and carbonate-replacement deposits in Chess Draw contain as much as 3110 ppm TREE, hosted in eudialyte, monazite, bastnäsite, and calciocatapleiite.

Feb 1, 2023

By John Davis Morgan

The uncertain world conditions of the present time require that the United States be prepared to meet: a. all-out nuclear war with attack on the United States b. limited wars (anything smaller than (a.) c. political, economic, and/or psychological warfare. Our present position as a major world power derives in large measure from our free institutions and our great industrial productivity, and our productivity in turn depends on an ever-continuing flow of raw materials from the earth - metals, minerals, fuels, and agricultural products. The United States, with only about 6% of the world's population, uses from one-third to two-thirds of the world's annual supplies of 'most metals and minerals. The United States strategic materials stockpiling program is designed to enhance our national security posture: as stated in the preamble of the Stock Piling Act, to decrease and prevent wherever possible a dangerous and costly dependence of the United States upon foreign nations for supplies of strategic and critical materials in times of national emergency. In times past, the Good Lord himself has ordered some stockpiling. The Book of Genesis in the Bible tells how Pharaoh of Egypt was directed to set aside one-fifth of the produce of the land in each of the seven good years to meet the needs of the seven bad years that were to follow: this would be a stockpile of about two years? normal use. Our cultural heritage often reminds us of the wisdom of stockpiling, as in the case of the stories about the provident squirrels that gather their nuts in an orderly manner in the f all to prepare for the winter's cold. And the old proverb about a bird in the hand being worth two in the bush points out clearly the value of something that is directly at hand.

Jan 1, 1960

By Donald W. Gentry

This section deals with one of the most fascinating aspects of mining the evaluation of mine investment opportunities. Be-fore proceeding further, it is important to clarify the meaning of some fundamental terms used frequently in the text. 6.0.1.1 Mine Valuation vs. Evaluation The words "valuation" and "evaluation" in a mining context are often used interchangeably. However, for the purposes of this section, a distinction is made between the two terms in accordance with commonly accepted practice. The word valuation in a mining project context has the rather narrow meaning of placing a dollar or other currency value on the worth of the project as a whole. In other words, the value of a mining project refers to a measure of the desirability of ownership of that property. As such, the major item of interest is, "what is the mine worth?," or `what is the value of the mine?" The value of a mining project may actually be determined in the marketplace at any specific point in time, or it may be estimated by one of several methods. The topic of mine valuation is discussed in more detail in Chapter 6.1. The word evaluation in a mining project context connotes the broader meaning of determining the numerical values of all

Jan 1, 2008

By Willard C. Lacy

A mining operation begins with prospecting and exploration-stages with long periods of investment and high risk of failure. However, success in exploration ultimately determines survival of the mining industry. Prospecting and exploration may discover evidence of a mineral occurrence and outline its size and character, but ore deposits that support mining are "made" through the collective efforts of project geologists, geophysicists, geochemists, metallurgists, engineers, chemists, lawyers, and even politicians (Joralemon, 1975). Some deposits may go through multiple cycles of rejection and recommendation, discovery and development, decline and abandonment, rediscovery and development, etc., as economic, technological, or political conditions change or geologic understanding is improved. Peters (1987, p. 233) graphically illustrates the normal life cycle of a mine and the position of exploration in the cycle (Fig. 4.0.1). During the past fifty years, mineral exploration has evolved from comparing evidence of mineralization of prospects with that of known deposits to a more quantitative science employing many facets of geochemistry, geophysics, multispectral sensing from space, computer data storage, analysis, modeling, and most importantly, a better understanding of ore genesis. This modem approach to exploration began in the late 1940s and continues to develop. Exploration efforts peaked in the 1960s with emphasis upon the search for porphyry copper deposits, Mississippi Valley lead-zinc deposits, and volcanogenic massive sulfide copper-lead-zinc deposits. It peaked again in the middle and late 1980s with emphasis upon micron-size disseminated gold and epithermal and stratiform precious metal deposits.

Jan 1, 2008

By K. V. Raj

As open pit mines continues to grow deeper, managing air pollution can become challenging. During arctic air inversion, the temperature of the air over the mine increases with altitude, and the cold, heavy, surface air is trapped in the pit. This problem is complex, and any solution will require an extensive understanding of the interactions between the aerodynamic movement of air, air inversion, meteorology, pollutant sources, and transport phenomena in the open pit mines. The availability of computational fluid dynamics (CFD) has elucidated the pollutant flow mechanism in open pit mines. Very few CFD studies have been published, especially the Large Eddy Simulation (LES), on the contaminant transport in deep open pit mines under arctic air inversion. The contaminant transport in an open pit mine under arctic inversion is due to a stable or nocturnal boundary layer in micro-meteorological terms. Understanding the physics of the stable boundary layer (SBL) is relevant to air flow and pollutant transport in deep open pit mines. This paper focuses on a Large Eddy Simulation (WMLES as Sub-Grid Scale Model) modeling of the SBL and pollutant transport in a large open pit mine.

Feb 23, 2014

By P. L. Sibrell

Three different refractory carbonaceous gold ores from the Carlin operation in northeastern Nevada were investigated to characterize the effect of passivation treatments on the nature of the carbonaceous material. The carbonaceous material was chemically isolated from the ores and passivated residues, and examined by FTIR spectroscopy, elemental analysis, and gold adsorption capacity. The main component of the carbonaceous material in these ores was found to be a naturally occurring activated carbon-type compound. Hydro-carbons were detected on rare occasions, but no evidence was seen for humic acids. Ore samples were passivated by autoclaving, or by treatment with sodium hypochlorite or gaseous Chlorine. In some of the passivation tests, a new peak was observed in the IR spectra of the isolated carbonaceous material, that was due to carbonyl functionalities. However, all of the passivation treatments tested decreased preg robbing significantly. This suggested that the appearance of the carbonyl peak was due to the severity of the conditions during passivation, rather than the method used.

Jan 1, 1990

By Robert A. Clifton

It seems probable that more and more minerals will be used in plastics as time goes on. This must occur because the minerals will; aid in processability, enhance the engineering properties, reduce the cost, and above all conserve large amounts of petroleum based chemicals. This paper examines the advantages and disadvantages of using the minerals and the ability of the domestic minerals industry to support this possibly very large undertaking. In the author's opinion, it can. This talk is excerpted from a forthcoming Bureau of Mines Information Circular.

Jan 1, 1985

By J. V. Thompson

The Powderhorn complex as a source of perovskite (calcium titanate) containing about 1.5% rare earths has been examined in several recent feasibility studies. Much promising exploration and process research has been done in recent years. This paper is presented with cautious optimism and with the acknowledgment that there may be some technical and economic areas yet to be explored. The Powderhorn carbonatite and alkalic stock in Gunnison County, Colorado, lies about 203 airlines km southwest of Denver at an elevation of 2450 to 2750 m (see Figures land 2). All of the mineable ore bodies are owned by Buttes Resources Company of Houston, Texas.

Jan 1, 1990

By Christopher Mark

Successful longwall gate entry design requires control of both vertical and horizontal stresses. Vertical, or overburden, stresses are most severe in the tailgate where they are concentrated by longwall panel extraction. Horizontal stresses, which are generally tectonic in origin, can be highly destructive during the development and headgate phases of longwall mining. The goal of this paper is to present the current state-of-the-art in detecting and controlling horizontal stresses. The information presented was collected through site investigations at 45 U.S. longwalls and an international literature review. The paper begins with a discussion of the present knowledge of regional in situ stress fields in the U.S. A review of available underground stress measurements from coal mines is presented, along with data collected by structural and petroleum geologists. The combined evidence indicates that a persistent ENE-EW trending stressfield is present throughout the eastern coalfields. Experience with horizontal stress in longwall mines is addressed next. The paper focuses on the northern Appalachian region, where the effects of horizontal stress have been most evident. Three case histories are discussed in detail, and the solutions each developed are highlighted. Observations made in the Southern Appalachian, Alabama, and Illinois coalfields are also described.

Jan 1, 1991

By William L. Young

I think I should let you in on one of Canada's best-kept secrets, if you will promise not to tell it all over the place. Believe it or not, good, honest, enterprising capitalism is still alive and flourishing north of our common border, and I am living proof that capitalism is still working for the little guy. My personal story of mining development in Canada isn't all that rare -- you've probably heard something like it from other areas and other days several times -- but my case brings it up-to-date. I would like to Tell you briefly the history of Northumberland Mines Limited, a contemporary case of individual enterprise getting a mining operation underway. And if I can do it you probably can too.

Jan 1, 1981

By James W. Estep

The sulphur shortage that has occurred in the past two years has directed attention more and more toward sour natural gas reserves, Wellhead values of sour gas vary widely depending upon the acid gas composition, location, market conditions, and necessary processing charges. Preparation of a saleable residue gas is considerably more involved and expensive than that normally encountered in treating a sweet gas. Recent revisions in sales gas specifications have increased capital costs and processing charges. The presence of hydrogen sulphide and carbon dioxide in a natural gas contributes to shrinkage factors that may approach 50%. Fuel required by the gas sweetening process and sulphur slant tail gas incineration also contributes to a further reduction in the volume of residue gas available for sale. The additional processing facilities involving gas sweetening, mercaptan removal, expanded utilities, sulphur recovery and sulphur handling, all demand additional operating and maintenance staff. A favorable sulphur market under certain conditions may justify the processing of sour gas whereby sulphur is either a by-product or a co-product, Five typical cases involving different compositions of sour gas are presented for evaluation. Capital costs, operating problems, and operating costs are presented in detail for full economic evaluation

Jan 1, 1967

By B. K. Mishra, B. Das, L. Panda, D. S. Rao

"The dissolution behavior of lateritic nickel ore containing 1.2% Ni, 40.6% Fe, 9.5% SiO2 and 9.59% MgO by sulfuric acid was investigated. The ore was characterized adequately by different techniques such as chemical analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), thermal analysis and Fourier transform infrared (FTIR) spectroscopic measurements. The characterization results did not reveal any distinct mineral phase for nickel; it was associated with mineral phases like goethite, hematite, chromite and serpentine in various proportions. The beneficiation studies by hydrocyclone, magnetic separation and flotation did not enrich the nickel value. Reduction roasting followed by magnetic separation indicated only 2%Ni with 28.9% yield. Consequently, the recovery of nickel values from the lateritic ore by acid leaching under different conditions was studied. The kinetics of leaching obey the first order rate equations. The recovery of nickel was found to be influenced by temperature. It was observed that at an acid concentration of 2M, leaching temperature 363 K, time 240 min and solid-to-liquid ratio of 1:10, it is possible to leach out more than 95% Ni.IntroductionThe demand for nickel is ever increasing. Nickel is used to impart specific properties to steel, titanium and aluminium, and also is used in petrochemicals, catalysts, batteries, etc. It has been estimated that nickel oxide ores account for about 70% of the world nickel reserves. However, most nickel is sourced from sulfide ores. Nickel is extracted from sulfide ore by size reduction, followed by flotation to obtain a nickel-rich concentrate. The concentrate is then pyrometallurgically processed by smelting to produce a nickel-rich matte after discarding an iron-rich slag. Due to the increasing demand for nickel in stainless steel and other alloys, nickel is also extracted from many secondary sources. The recovery of nickel from oxide ores is now gaining momentum, and more exploitation of this ore is being attempted by advanced as well as environmentally feasible, cost-effective techniques. Dalvi et al. (2004) has reported that, due to the increase in demand, the world nickel production from laterites is expected to increase every year from the current level of production. In recent years, investigations of the use of low-grade ores, spent catalysts, clays, etc., have intensified to meet the market demand and also due to a shortage of high-grade nickel bearing ores (Al-Mansi and Abdel, 2002; Baba et al., 2009; Ismail et al., 2011)."

Jan 1, 2015

By Susanne Pignolet

Ore microscopy has been applied to the complex lead-zinc-copper-cobalt-nickel ores from the Madison Mire in the Fredericktown subdistrict of the Southeast Missouri Lead District to predict potential beneficiation problems. It has been found that in some portions of the ore deposits, textures are present which may result in metal losses. In ores from the Bonneterre Transition Zone the intimate association of siegenite with chalcopyrite may result in cobalt and nickel losses to the copper concentrate. In ores from higher stratigraphic horizons, this association is relatively uncommon, and siegenite is commonly associated with bravoite. This latter association will increase the recovery of the cobalt and nickel in bravoite, even though some of the fine-grained bravoite will not be recoverable. Other textures which may result in potential beneficiation problems include coatings of covellite on chalcopyrite and inclusions of sphalerite in galena.

Jan 1, 1983

By S. S. Hsieh

Bench-scale beneficiation studies were made on Idaho dolomitic phosphate rock using the TVA carbonate flotation process. The process employed diphosphonic acid as a phosphate mineral depressant and fatty acid as a carbonate mineral collector. Silica was subsequently rejected as float using an amine collector, with phosphate product recovered as the sink fraction. Two samples of prepared flotation feed from commercial operation were used; one contained 21% P205 and 3.2% MgO, and the other contained 26% P205 and 1.8% MgO. The results indicate that concentrates containing 31-33% P205 and 1% or less MgO can be obtained, with P205 recovery of about 80%.

Jan 1, 1984

By H. W. Breathitt

World demand for phosphate rock has increased significantly in the past fifteen years. Prior to the early 1960's, most of the world production was obtained from Florida, North Africa, and Kola. As the 1960's arrived, new mines in North Florida and Eastern North Carolina, as well as expanded production in the Western United States, .increased domestic production. Many new mines overseas have also become significant. This includes countries such as Senegal, Togo, Israel, Spanish Sahara, and Jordan. Limited production, often as by-products, has been noted in South Africa, Brazil, and other countries. In recent years, and even recent months, we have learned of many new areas being considered as potential sources of phosphate rock. This includes Australia, Saudi Arabia, Mexico, Colombia, and Brazil. Many other developing countries have discoveries and are considering their new deposits, often with difficult beneficiation problems, as potential sources of phosphate. These factors all relate to expanded world, population and the demand for more fertilizer products to produce food. In this paper, four areas of the world with different types of phosphate deposits are briefly reviewed to contrast the ore beneficiation problems to Florida procedures--long considered the "standard" of the industry, at least for most of the United States' domestic production. Agrico has three large operating mines in Florida with total production capacity exceeding seven million tons per year. Here, pebble phosphate (+14 mesh material) is produced without the use of flotation, whereas all of the material finer than 14 mesh is subjected to flotation beneficiation to upgrade into high grade concentrates.

Jan 1, 1977

By H. R. Bullis

Lupin is located on the shores of Contwoyto Lake at lat. 65° 48'N, Long. 111° 15'W and lies about 80 kilometers south of the Arctic Circle. Since start up in 1982 the mine has produced over 2.15 million ounces of gold from 6.66 million tonnes of ore grading 10.63 gm/tonne. Total remaining reserves at 1993 year end were 5.1 million tonnes at a grade of 9.11 gm/tonne (1.65 million ounces). This is sufficient for 7 -8 years at the present annual production rate of about 200,000 ounces. The Centre and West Zones of the deposit are open to depth. The deposit is in an Archean metaturbidite sequence of the Contwoyto Formation, which has been mapped as part of the Yellowknife Supergroup of supracrustal metasedimentary and metavolcanic rocks making up part of the Slave Geologic Province. These rocks have been subjected to regionar and contact metamorphism and to several phases of deformation. Six stages of Archean plutonism have been identified and all Archean rocks have been cut by Proterozoic diabase dyke swarms. Gold mineralization in the Lupin deposit is commonly fine grained and associated with pyrrhotite and arsenopyrite in amphibolitic banded iron formation. The gold-bearing portions of the host iron formations are characterized by the presence of multiple quartz veins and the pervasive replacement of grunerite by hornblende. In sparsely mineralized portions of the host iron formation, zoning of sulfides about quartz veins is clearly seen with the arsenopyrite halo being more restricted around the veins than the pyrrhotite halo. In well mineralized portions, quartz vein densities approach one vein per metre along strike. In these areas pyrrhotite distribution in the iron formation is more pervasive and the rock takes on the appearance of a banded sulphide rock.

Jan 1, 1995

By M. F. Corcoran

Rapid advances have been made in the past few years in the application of automatic controls and instrumentation to iron ore pelletizing plants. Present practice in applying instrumentation and control to the Grate-Kiln system of iron ore pelletizing is described. Major control points and loops are tabulated. Future trends in the application of digital control including computer data logging systems are described.

Jan 1, 1965

By M. A. Alan

The Bellavista Gold Deposit lies 75 Kms north west of San Jose, the capital of Costa Rica, Central America and 3 Kms north east of Miramar, in the Province of Puntarenas. The total road distance from San Jose to the deposit is 120 Kms all paved road except for a 2.5 Km graded, gravel road on the property (Figure 1). Infrastructure services in the Miramar-Puntarenas area are well developed with electrical power distribution, a modern port facility and community services being available. The deposit lies on the south west flank of the Tilaran Mountain Range between an elevation of 550 and 800 meters above sea level. The local topography is steep, originally covered with pre-montaine, tropical wet forest vegetation which has been largely destroyed due to clearing for cattle grazing. The annual rainfall is approximately 2,950 mms, 90% of which occurs between May and October.

Jan 1, 1992

By X. Cheng

The mechanism of cathodic decomposition of pyrrhotite was studied in deoxygenated solutions at natural, near neutral pH using potential and cyclic voltammetric measurements. Reaction products on pyrrhotite surfaces were examined by AES and XPS, and by analyzing the voltammograms for the electron balance of the reactions. Surface properties of the pyrrhotite/solution interface were characterized using ac impedance technique. The parameters of an equivalent circuit were determined by the nonlinear least squares fit (NLLSF) technique. The effect of cathodic polarization on floatability was investigated by micro-flotation tests. Possible implications to the flotation separation of chalcopyrite-pyrrhotite ores are discussed.

Jan 1, 1993

By A. Noble

"In coal and mineral processing, several numeric parameters are used to quantify the separation performance of unit operations. For density-based separations, the partition curve is used as the starting point for many stages of diagnostic analyses. The curve is often quantified by its midpoint slope sharpness, and this single value is subsequently used for technical evaluation, benchmarking, and comparison. While this analytical approach does depict misplacement by relative density class, it inherently prioritizes middling separation and does not consider process economics or the micro-price value of individual classes. An alternative parameter, the organic efficiency, does indirectly consider process economics, but it does not reveal information on the root cause of lost revenue or misplacement. In this paper, a new analytical approach, the partition moment of inertia, is introduced. This parameter reconciles the technical misplacement data derived from the partition curve with the economic data derived from micro-pricing. The result is a new analytical procedure that promises better use of performance data. IntroductionPartition curves are commonly used in the characterization, evaluation and simulation of various physical separators. In mineral processing, partition curve analysis is routinely applied to hydrocyclones, screens, density separators and other beneficiation technologies that are based on intensive physical properties. Graphically, the partition curve depicts the recovery of particles as a function of the physical property on which the separation is based, such as particle density, size or magnetic susceptibility. Given the probabilistic nature of many real separators, the partition curve often exhibits a characteristic S shape (Fig. 1), similar to a cumulative normal distribution. Other geometric features of the curve are also depicted in Fig. 1, including the high and low closeout, or bypass, values; the midpoint slope; and the separation cut point, defined as the property value with 50 percent recovery.Partition curve analysis was originally proposed to evaluate coal washability (Tromp, 1937). Given the limited computational resources at the time, the analytical methods relied heavily on graphical construction and interpretation of the curve. Owing to the simplicity of calculation and interpretation, many of these graphical approaches are still widely used for performance analysis today. The most common calculations are based on the slope of the partition curve at the midpoint. Increased slopes correspond to enhanced separation performance, as a perfect separation exhibits a stepwise transition from 0 to 1 at the desired cut point, that is, an infinitely large slope. One common formulation of this slope, the Ecart Probable, Ep, is derived by evaluating the slope between the 25 and 75 percent recovery points:"

Jan 1, 2016