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By J. A. McKeown, B. M. Sanders, A. Dadgar, R. H. Sergent

This paper describes the leaching of gold with Geobrom® 3400 from a very rich (6.2 kg/tonne) black sand concentrate and its subsequent recovery by ion exchange resins and solvent extraction. The dissolution of gold from black sand ranged from 94 to 96%. Gold loadings and recoveries of nearly 100% were achieved by both ion exchange and solvent extraction methods. The kinetics and equilibrium of loading gold onto ion exchange resins and its elution from the resin were studied. The commercial ion exchange resins PAZ®- 4, DOVEX®- 21K, and Amberlite® XAD- 7, and Great Lakes Chemical experimental GLR-30 were evaluated in this work. Diethylene glycol dibutyl ether was used in all the solvent extraction work for gold recovery from Geobrom leach solution. The consumption of Geobrom was about 130 kg per tonne of the concentrate processed. Therefore, the cost of lixiviant to extract 3.11 x l0-2 kg of gold from the black sand was only about $1.00. Based on the electrochemical regeneration of bromine, the economics of bromine process vs. cyanidation were investigated.

Jan 1, 1990

By R. L. Grayson

Compliance standards for respirable dust which are reduced because of high quartz concentrations have become an industry-wide problem. Research on the physical and chemical character of quartz-classified particles in respirable coal mine dusts indicates that they may exist in intermixed layers or may be coated by clay or coal material. The relative amount of intermixing varies with the coal seam being mined. If most of the quartz particles of a mine dust are "pure," then the dust may have a high fibrogenic risk potential because of truly free silica and the compliance standard should be lowered. If, however, the quartz is locked inside another material matrix, or coated, a reduced compliance standard may not be appropriate.

Jan 1, 1990

By M. Deutsch

A common casualty of modern open pit mine optimization is the assurance that the resulting design is actually achievable. Optimized mine plans that consider value and a bare minimum of precedence constraints do not, in general, translate into practical, operational mine designs that can really be used in the field. Ultimate pits may come to a sharp point at the bottom. Schedules may require taking small parcels of material from many disparate areas of the pit in a single period. And grade control polygons may be ragged, narrow, and not minable with realistic equipment. In this paper all of these problems are addressed by encoding these three fundamental open pit mine optimization problems as maximum satisfiability problems. Maximum satisfiability provides a useful framework for problems that are non-linear and may guarantee the optimality that metaheuristics cannot. INTRODUCTION Open pit mines are large and complicated operations, which require significant initial and ongoing investment. A single mine may employ hundreds or thousands of people and creates substantial benefits for both the surrounding and global communities. Planning an operation of this magnitude requires a lot of effort and cannot be done optimally by hand. Mining engineers today rely on many techniques from operations research to guide decision making, and to maximize the value of the mine. Techniques including linear programming, metaheuristics, and network algorithms are all used to solve different problems throughout mine design and optimization. However, techniques based on Boolean satisfiability, including the optimization extension of maximum satisfiability, have not seen much use in mining despite being used in many other fields including electronics design, scheduling, and artificial intelligence. We claim that maximum satisfiability is a useful and meaningful way of expressing and solving optimization problems in mine planning. However, this technique does not come without challenges; the problem is NP-hard, and modern techniques for solving these problems can struggle with the number of variables and clauses that a typical mining problem requires. Also, some of the constraints that mining must contend with do not fit nicely into the satisfiability paradigm. Despite these challenges, we believe that maximum satisfiability provides a useful framework for considering operational constraints and expressing some problems that other techniques can't easily express. Maximum satisfiability can be solved exactly, yielding the true optimal answer which metaheuristics cannot guarantee. In this paper we show the applicability of maximum satisfiability to mining by specifying three fundamental problems in open pit mine optimization. We show how these fundamental problems can be formulated and how they can be extended within the framework of maximum satisfiability. For the remainder of the paper we first give a brief background on common elements between the three problems and an introduction to satisfiability. Then we tackle the three problems; the Ultimate Pit Problem, the Block Scheduling Problem, and the Grade Control Polygon Problem. In the Ultimate Pit Problem we specifically show how to extend the problem to support a minimum mining width – a coveted result for many mining engineers. We then discuss some of the complexities and shortcomings of this framework and possible research directions.

Jan 1, 2019

By L. C. Morales

During my College days in Mexico City, my Mineralogy Professor used to say "Mexico is the Horn of Plenty, rich in minerals, and it is easier to say which minerals are not found instead of stating all that exist. He said that the only ones missing are bauxite, diamonds and titanium ores." Today, twenty years later, a rutile mine in Oaxaca is in successful operation. Mexico has an area of approximately two million square kilometers, with volcanic activity, large shores and mountainous areas reaching as high as 6,000 meters above sea level. These conditions are favourable for most mineral deposits, some -of commercial value and others as a source of mineral samples only. (fig. No.1) In addition to vast mineral wealth, Mexico has -another valuable asset in .his people. Even before the discovery of America, natives were successfully mining metals, and during the Colonial --days, the mineral deposits were mined to increase the wealth of Spain, and it increased the --knowledge of mining. All this experience was passed along from generation to generation, and created a tradition of mining and minerals processing engineers, that currently account for approximately 182,000 persons supported by mining related activities.

Jan 1, 1994

By C. R. Kuhn

From 1968 to 1975, most work in surface modification of inorganic materials involved silane coupling agents. A silane coupling agent can be described simply as an oganosilicon chemical having a general formula RSi-X3 wherein the R group is attached to a silicon in a thermally and hydrolytically stable manner, and X is a hydrolyzable group usually having an alkoxy functionality. About 1975, Kenrich Petrochemicals brought into the market place titanate coupling agents. Titanate coupling agents usually consist of one alkoxy group and three functional groups attached to a central titanium atom. Zircoaluminates became available in about 1982. Zircoaluminate organometallic coupling agents, which vary principally in their respective organofunctionalities, arise from a basic technology in which two different types of organic ligands are selectively bound to a low-molecular weight zircoaluminate backbone.

Jan 1, 1995

By Y. Guan

The dissolution behavior of copper and gold from their pure state and from Au/Cu alloys in cyanide solutions has been investigated using a rotating disc. Oxygen was used as an oxidant. The effect of the composition of the alloys, stirring speed of the disc, concentration of lixiviants and temperature on the overall dissolution kinetics has been studied. Gold/copper alloys of three compositions were used in this study. The atomic percent of gold in these alloys was 75, 50 and 25, respectively. The dissolution behavior of these three alloys was compared with that of pure gold and of copper under the same chemical conditions. In general, the dissolution of copper and gold from alloys is partially controlled by surface chemical reaction and largely by mass transfer.

Jan 1, 1992

By Welland L. Ott, Hans J. Rumland

The Falconbridge Dominicana laboratory receives samples from all parts of the operation. Ore, metal and oil samples are taken by operating departments, gas and water samples by the laboratory staff. Physical sample preparation is essentially standard and produces comminuted samples for wet-chemical analysis and X-ray fluorescence analysis (XRF). T he main operating sections of the laboratory are described indicating in each case the type of instrumentation and method used, sample types analysed and comments on problems experienced. Emphasis is given to the sample preparation and X-ray sections especially with regard to the difficulties caused by our heterogenous ore material, calibration of the instrument and operational malfunctions. General problems related to our remote location and the tropical climate are discussed. Limited statistics on instrument availability, and stability, accuracy, precision, etc., are given.

Jan 1, 1979

By A. W. Easton

INTRODUCTION This presentation will address changing trade patterns in lead and zinc from the mid 1980's to the early 1990's. Lead and zinc deposits are developed where they are found in many parts of the world. As many are not in major consuming areas, there is significant international trade in both lead and zinc concentrates and in refined metal. Forecasts of mine production have been analyzed, primary and secondary refining capacity and future consumption levels have been estimated, to arrive at the changes in trade patterns expected during the next half decade. This paper will first address concentrate and metal trade patterns for lead, then for zinc, and finally some remarks will be made on captive mine/smelter agreements, on regional trade agreements, and on barriers to trade. I would like to note that. there is only a small international trade in semi-fabricated products such as zinc die-cast alloy, zinc oxide, lead oxide or rolled lead and zinc. Most of the world's zinc and lead trade is in concentrates or refined metal. LEAD TRADE PATTERNS Lead Concentrates Six countries are exporters of lead concentrates. Three countries are in the Americas - Canada, Mexico and Peru, with two in Africa - Morocco and South Africa (including Namibia), and Australia. Due to the limited growth in lead consumption and consequent minimum investment in new production facilities expected, mine and metal production levels and future consumption levels are not forecast to change much between now and 1990. Accordingly, the tonnage of lead concentrates exported will remain essentially unchanged from these six countries. In total they have exports of 480,000 metric tonnes (metal content)* and by 1990 this figure is forecast to rise only slightly with the only increase taking place in Mexico. The concentrates are exported mainly to Western Europe & Japan. Apart from these six main lead concentrate exporting nations, a significant change is expected in the United States. In the mid * All concentrate trade figures are based on metal content

Jan 1, 1986

By Thomas J. Wright

The evaluation and development of the Eastern North Carolina phosphate deposit resulted in one of the world's largest and most modern phosphate mines and fertilizer complexes at an investment in excess of $90,000,000. The resulting ore beneficiation process showed excellent correlation with pilot plant data. A number of variations from current industrial practices were introduced and projected from bench scale tests through pilot plant to production. Principal among these variations were the following: 1) removal of magnesium by classification, 2) simultaneous flotation of coarse and fine phosphate, 3) the use of saponified fatty acid, 4) utilization of filter wash water for deoiling, 5) utilization of a rougher concentrate for acidulation, 6) calcination of flotation concentrates, and 7) elimination of grinding prior to the manufacture of phosphoric acid.

Jan 1, 1971

By B. K. Parekh, R. H. Mehta

Handling of fine coal is an importance issue for coal as well as the utility industry. Reconstitution in form of pellet or briquet would be desirable if it could be done economically. This paper evaluates the effectiveness of three binders e.g., asphalt- emulsion, corn starch and Brewex, in forming pellets of ultra-fine clean coal. It was found that asphalt emulsion and corn starch were not effective binders for ultra-fine clean coal, however, Brewex provided excellent quality of pellets, which exceeded all the minimum quasi requirements of coal pellets. INTRODUCTION Advanced coal preparation techniques (physical or chemical) are designed to process ultra-fine (minus 200 mesh or 74 pm) coal. The average particle size of the clean coal product is about 25 pm. Currently available dewatering techniques are effective in providing a 25 to 30 percent moisture product of this size coal slurry (Parekh et al. 1989). Handling and utilization of this dewatered ultra-fine size coal is difficult. Reconstitution, which includes pelletization, briquetting, extrusion, etc., of the dewatered coal product provides an ideal answer to handling and transportation problems. However, reconstitution of fines in the coal industry has not been successful due to various reasons. The most important criterion for its unsuccessful application in the coal industry is the cost of the binder (Capes et al. 1965). Various methods of reconstitution, such as briquetting, disk pelletization, extrusion pelletization and roller and die-pelletization, have been tested for fine coal agglomeration (Conkle et al., 1991) (Richards, 1990). Conkle et al., (1992) have provided a detail analysis of each technique in terms of moisture and operating cost requirements. According to Conkle, briquetting requires a product containing very low moisture, whereas pelletization can be done with coal containing up to 30 percent moisture. Currently available dewatering technique provides about 25 percent moisture product, thus, pelletization appears to be an ideal route for reconstitution. In this paper, results are presented on the comparison of three different binders i.e., asphalt-emulsion, corn starch and Brewers condensed solids (BCS or Brewex), for fine coal pelletization.

Jan 1, 1995

By C. H. L. Bastos

A physical and chemical characterization study was carried out on 483 kaolin samples from 2.9 km2area at the Para Pigmentos mine along the Capim river, northern Brazil. The samples obtained from cores, drilled with regular spacing of 100 m, were evaluated using grit percentage, particle size distribution (psd), brightness, leachability, magnetic response and viscosity. These parameters were correlated with each process step in the plant and also the physical and chemical properties of the ore and finished product. Cluster analysis was performed and four main groups of kaolin were identified. These were then related to their performance at the various process steps and the quality of the initial product. These groups are well defined by plotting grit X “psd” and TiO2x “psd” in scatter plots.

Jan 1, 2004

By R. V. Ramani, W. Miola

The MSHA prescribed method for the determination of quartz in airborne respirable-dust samples from underground coal mines is the P-7 method, a combination of low-temperature, radio-frequency ashing (LTA) and infrared analysis (IR). There is no prescribed procedure for quartz analysis in bulk samples of coal and host rock. Dispersive infrared (IR), Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) methods are most commonly used for the analysis of quartz in powders. Several aspects of the experimental procedures, such as the preparation of the analysis sample from bulk samples, ashing techniques, scanning procedures, peak measurement location, calibration techniques, sample amounts, size consist and data interpretation, affect the results from each of the methods differently. Significant differences in analytical results obtained from X-ray diffraction (XRD) and infrared spectroscopy (IR) on the same samples are reported. All studies point to the need for reliable quartz analysis methods. In a recent research program, a procedure for preparing bulk-coal and host-rock samples for quantitative quartz analysis was developed. Further, the results from X-ray diffractometry and infrared spectroscopy for quartz content on identical samples were compared. Calibrations with pure and mixed standards were used to assess the influence of particle-size distribution, matrix and calibration on the analytical results. In this paper, several issues concerning the measurement of quartz in the samples of coal, host-rock and airborne respirable dust from mines are outlined and quantified.

Jan 1, 1996

By J. D. Miller

"Bastnaesite is one of the important mineral resources for the production of rare earth materials, and it is typically associated with calcite and quartz as gangue minerals. Fatty acid or hydroxamic acid are recommended collectors for bastnaesite flotation. In this research, potassium lauryl phosphate was expected to provide a stronger flotation response for bastnaesite than for the calcite and quartz gangue minerals. Using potassium lauryl phosphate as collector, the results of captive bubble contact angle measurements, zeta potential determinations and microflotation experiments for bastnaesite, calcite and quartz are reported. Greater selectivity for bastnaesite was achieved using potassium lauryl phosphate than using octyl hydroxamate as collector. These results indicate that potassium lauryl phosphate might be a promising collector in the flotation of bastnaesite ores. The computation results of universal force field (UFF) interaction energies for the mineral-reagent interactions are also reported and were found to correlate well with the experimental microflotation results.IntroductionBastnaesite ((Ce,La)FCO3) belongs to the mineral class of semisoluble salt minerals, whose characteristics include ionic bonding and limited solubility in water. Bastnaesite, for the most part, contains the cerium subgroup or the lighter rare earth elements (Zhou et al., 2014). The Mountain Pass deposit in California in the United States and the Bayan Obo deposit in Mongolia in China are the two major deposits of bastnaesite (Azizi et al., 2016; Satur et al., 2016). Calcite and/ or quartz are common gangue minerals in these and many other rare earth deposits (Jordens et al., 2014)"

Jan 1, 2017

By D. Spitty

There are enormous complexities with mine planning and the problem itself presents a huge challenge to the existing mine planners performing this activity. Mine planning optimization supports planners to determine ?What are the best increment excavation sequence and the best material blending combination such that throughput, quality, cost, utilization and Net Present Value (NPV) targets are met?? It is achieved through using an advanced scientific approach that has been specifically adapted to address the mine planning dilemma.

Feb 23, 2014

By J. J. Reilly

The Vesta Mines of the Jones & Laughlin Steel Corporation operate in the Pittsburgh Seam in Washington County, Pennsylvania. This seam is overlain with a drawslate, 12" to 16" in thickness, which slimes readily when wet. Because of the need for a uniformly good quality metallurgical coal, the amount of reject, together with the top and particle sizes of the raw coal feed, is a serious problem at the Vesta Preparation Plant. The Preparation Plant operates two, seven and one-quarter hour shifts per day and processes 2,100 tons per hour of raw coal feed. The third shift is, used for planned maintenance of equipment. Since the water clarification equipment is so vital in insuring a uniform product, there is no alternative but that it be in operation at all times. To insure this continuous operation,. well-planned maintenance is a necessity. For years, Plant Management has kept performance records of the various units to determine the renewal dates of vital component parts, the length of wear, the various materials used in the manufacture of the equipment, and the labor cost for renewal. These records have been of inestimable help in planning an effective maintenance program to insure continuous operation of the various units.

Jan 1, 1959

By Charles R. Marek

There is an ever-increasing need for quality construction materials to provide the necessary housing and transportation facilities required for the protection and movement of people and goods. By the year 2000, requirements for housing in the United States will have doubled due to population growth. Requirements for transportation facilities in this same period will also have increased substantially. Further, all existing facilities for both housing and transportation will require substantial maintenance of one form or another. Aggregate is the basic material of the construction industry. There is some occurrence of aggregate source material in virtually every state of the United States, and in every country in the world. United States reserves of commercially useable aggregate have never been systematically estimated and are probably so vast as to be incalculable.1 However, in many areas its existence is largely negated by inaccessibility. Often it is lodged deeply or intricately in the earth or it is too distant from markets to offer a desirable "return on investment" under the present economic structure. Other factors that prevent its utility are the occurrence of small scattered deposits that individually are too small to justify the necessary capital investment for exploitation and collectively are too widely disseminated; also, the aggregate nay be deficient in certain desired chemical or physical qualitites.1

Jan 1, 1974

By G. M. Wilemon

The U.S. Bureau of Mines has conducted preliminary investigations on the leaching of phosphate ores obtained from deposits in the western United States using sulfuric acid (H2SO4) in the presence of methanol. Phosphate extractions in excess of 80 pct were obtained on an ore sample from Pocatello, ID. Initial leaching studies using the ore as received yielded extraction levels of approximately 35 pct. However, when the sample was ground for as little as 5 min in a rod mill, in methanol, then treated with HzS04, 82 pct extraction was achieved. The R2O3-P2O5 (R2O3 = Al2O3 + Fe2O3) ratio of the starting material was 0.11. Solubilized products after leaching exhibited an R2O3-P2O5 ratio of 0.02, which is well within desired limits. These results illustrate the potential of acid-alcohol leaching for recovering phosphate values from marginal-grade ores and as an alternative to methods involving current beneficiation techniques that yield lower phosphate recoveries.

Jan 1, 1992

By Emily Sarver, Cigdem Keles, Jonathan Gonzalez

The study re-examines respirable coal mine dust samples using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). It finds that SEM tends to overpredict the abundance of dust from rock strata and underpredict coal content, possibly due to coal-mineral microagglomerates (MAGs). The findings suggest that MAGs could be valuable in improving dust controls in mines.

Feb 10, 2022

By James P. Connell

The Berkeley Pit of The Anaconda Company is located on the southeast slope of the Butte Hill, the legendary "Richest Hill on Earth," and is one of the largest pit operations in the world completely dependent on truck haulage. Through October 31, 1968, the Berkeley stripping and mining operations have moved more than 442,589,000 tons of material. Present scheduled production is at the rate of 260,000 tons per day, with a record quantity of 306,900 tons having been hauled on September 23, 1968. Although the Berkeley Pit has been in production only a little more than ten years, it has been the proving ground for many of the presently used large trucks. Beginning with the original R. G. LeTourneau 75-ton electric truck in 1960, Unit Rig 85- and 100-ton electric drives, Haulpak 65- and 105-ton electric drives, and Caterpillar 100-ton electric drives have all been tested under production conditions. In addition, engine development has kept pace with both 1000-hp diesel and 1100-hp gas turbine engines now under test. As the size of the Berkeley operation has grown, the truck fleet has changed in size and appearance in order to maintain economic mining costs. The original fleet consisted of forty-three 36-ton trucks with conventional mechanical drives. The present fleet is made up of eighty-nine trucks: nineteen 85-ton Unit Rig electrics with 700-hp diesel engines; sixty-nine 100-ton Unit Rig electrics with either 700- or 1000-hp diesel engines; and one 100-ton Unit Rig electric with an 1100-hp gas turbine engine.

Jan 1, 1969

By James J. Scott

Friction Rock Stabilizers, trade name II Sp 1 it Sets'" have been under research and development by the author and the Ingersoll-Rand Company since February of 1973. The United States Bureau of Mines and the Mines Enforcement and Safety Administration as well as many mining companies have cooperated in field testing the device. Split Set rock anchors are distinctively different from the widely used mechanical rock anchors or fully grouted rock anchors. They control ground movement internally in a manner that allows controlled deformation during the early phase of the ground reaction curve but then, as secondary creep develops, anchorage per unit length increases and they serve to strengthen and stabilize the opening for long periods of time. The history of research and development of the Scott Split Set rock anchor system with accompanying laboratory and field test data is presented in this paper.

Jan 1, 1977