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By Norris E. Brooks

MAPCO Inc. is an integrated energy company involved in oil, gas, gas liquids, pipelines, and coal. The Coal Segment has installed a simple incentive program based on profit, tons produced, and hours worked at each operation. The plan has two segments-production bonus and profit sharing. Each segment is described and the results, which include high productivity, good safety, and high morale are discussed.

Jan 1, 1983

By Emily Dieckman, Claire Kincaid

"When most people think “miner,” they picture an older white man in a dusty shirt and suspenders. He’s holding a gas lamp and a pickaxe, peering at the walls of a dimly lit cavern. This image, while steeped in heritage, is no longer representative of what mining is: a global, increasingly diverse industry.It’s an industry made up of individuals like Zambian-born Chushi Mwewa, PE, president of Southlands Engineering, LLC in the United States and managing director of Southlands Engineering Limited in Zambia; Navajo tribe member Peter Denetclaw, manager of environmental programs and Navajo relations at Freeport-McMoRan; and Chinese and Jewish Alyssa Hom, a project engineer at McCarthy Building Companies.According to the Austrian Federal Ministry of Science, Research and Economics, 168 out of the world’s 195 recognized countries have some mining or mineral resources activity, and the mining industry directly employs more than 25 million people across the globe.However, according to McKinsey & Company’s 2017 “Women in the Workplace” study, white males hold 67 percent of C-Suite positions and 70 percent of senior vice president positions in the corporate world, and mining is no different. This uniformity among leadership has been tied to lower levels of employee engagement, innovation and business growth. The bottom line is this: Diversity is good for business. The question industry leaders must now ask themselves is not “Will we promote diversity?” but “How will we promote diversity efficiently and permanently?”More than 80 industry professionals, consultants and students gathered to discuss this question and share stories at the “Developing Diversity in Mining” workshop organized by the University of Arizona’s Lowell Institute for Mineral Resources (IMR), held during the 2017 SME Arizona Conference in December 2017.Brad Ross, co-director of the IMR and one of the facilitators of the workshop, said he felt diversity was important to discuss because he has witnessed its benefits throughout his career in the mining industry.“By creating a team of people with different experiences and perspectives, a company is better equipped to see the big picture and to creatively tackle problems,” he said. Speakers from industry and academia,including Mwewa, Denetclaw and Hom discussed the challenges surrounding achieving diversity and inclusion as well as the roles and responsibilities of different stakeholders."

Jan 2, 2018

By Peter N. Yanker

The two types of dryers used in the drying of copper concentrates are the rotary dryer and the spray dryer. The rotary dryer has until recent history been the traditional drying method used, Although spray dryers have been used in the chemical field for many years it is only recently that they have been accepted for drying of copper concentrates. The comparison made here will apply in a narrower sense to the drying of copper concentrates as fed into the reverbatory furnaces of the Smelter. To compare a rotary dryer and a spray dryer, which are two totally different methods and pieces of equipment, it is best to view them as systems each made up of certain elements

Jan 1, 1976

By Leonidio Stegmiller

Since the petroleum crisis in 1973, charcoal1 is being considered one of the most important fuel for the Brazilian consumers, mainly for pellet's producers. In replacing fuel by charcoal mixed up with ore, obviously one of the first thing to be investigated is its influence in the product's quality. Special attention has been given to the metallurgical characteristics. This paper infocus the effect of increasing dosings of charcoal to the pellet's porosity and how other physical and metallurgical characteristics will be affected accordingly. This work was carried out using two different finesses of charcoal and dosing varied from 0.5 to 2.0%.

Jan 1, 1982

By A. B. Cecala

Two recent Bureau studies evaluated workers' dust exposures in automated pallet loading processes. The first study involved a Bureau designed dust control system using a push-pull ventilation technique. The unit was shown to reduce workers' dust exposures by 76% during pallet loading at a ground silica operation. A hydraulic lift table was used to automate the bag stacking process; this kept the loading height constant throughout the entire pallet loading cycle. The second study evaluated different commercial automated pallet loading systems. These systems automatically stack the bags onto pallets, shrink wrap the pallets, and deliver the pallets to a fork lift pickup location. Results from a ground silica evaluation site indicated respirable dust samples taken were below the Threshold Limit Value (TLV) as established by the Mine Safety and Health Administration (MSHA).

Jan 1, 1990

By Gerald Zink

The work described in this paper is sponsored by the Bureau of Mines for the purpose of accelerating the drilling of roof bolt holes and reducing the quantity of materials needed to fill each hole. A high-speed small-hole drill has been fabricated and tested in the laboratory. High priority has been given to safety, reliability, and compatibility with underground coal mining practice. The combination of drag bits and erosion jets is designed for high penetration rate, long wear life, and uniform hole size in a variety of sedimentary strata. A reliable high-pressure high-speed swivel feeds water to the bit at about 4 1/min (1 gpm). The duplex hydraulic intensifier which drives the jets has a 40 kw capacity (30hhp) Results of recent full-scale laboratory testing are presented.

Jan 1, 1978

By E. F. Draskovich

In 1984 a high temperature heat recuperation system was installed in the pellet plant of the National Steel Pellet Company located in Keewatin, Minnesota. The system is similar to those of Cleveland Cliffs Empire and U.S. Steel's Minntac operations. It recovers hot process air from the cooler by induced flow, and directs it to an intermediate zone between the drying and preheat zones on the grate machine. This system recently underwent further modifications in April 1985, following initial operation in 1984. The M. A. Hanna Company, which manages the property, developed the design criteria and made the subsequent recommendations for modification through its research facility in Nashwauk, Minnesota.

Jan 1, 1986

By N. Myung, G. Hwang, H. Kim, Y. Han, S. Choi

"According to research presently being conducted on selective lithium recovery in seawater, inorganic adsorbents with high selectivity and capacity for capturing lithium ions from liquid lithium resources are called lithium ion-sieves (LISs). Their low toxicity, low cost and high chemical stability make LISs suitable for lithium recovery from seawater. In the present study, the ultrathin LMO nanofibers with controlled diameter were successfully fabricated by an electrospinning technique with a hypothesis that greater aspect ratio (i.e., smaller diameter) would lead to the enhanced recovery of lithium ion from seawater. Design of Experiment (DOE) and dimensionless analysis were performed to systematically optimize the diameter and morphology of nanofibers. Several complementary techniques including FE-SEM and XRD were used to evaluate the physical/physicochemical properties of the nanofibers. Lastly, the lithium ion recovery was tested for the nanofibers with different physical properties using lithium ion solution. INTRODUCTION Demand for lithium resources is increasing in many industries across the world.1-2 However, the conventional resources for lithium is very limited, and it even gets worse to secure the resources due to low grade and/or complexity of feed materials. Much effort has been, therefore, devoted to obtaining lithium from aqueous lithium resources. Several methods such as solar evaporation3-4, co-precipitation5, and solvent extraction6 have been proposed for recovering lithium from an aqueous lithium source, but there are limitations on its use; It takes a very long time or conditions such as temperature, pH and Mg/Li ratio are severe. Lithium ion-sieve (LIS) materials are considered as a good lithium adsorbent because of their unique chemical structure that can selectively separate lithium ion from brine and seawater.7- 10 Furthermore, their low toxicity, low cost, and high chemical stability make LIS suitable for lithium recovery from aqueous lithium resources. Spinel hydrous manganese oxide (HMn2O4) derived from spinel lithium manganese oxide (LiMn2O4) after topotactically extracting lithium from the spinel structure by acid treatment is most widely investigated LIS.10, LIS materials have been actively studied in various forms for easy handling and high efficiency (i.e. membrane11,12, foam13-14, granular15,16). Among them, the 1-D nanostructure LIS with high specific surface area is excellent in efficiency.9 In this study, we present the part of our recently submitted work17. Specifically, we fabricated systemically lithium manganese oxide nanofibers with different diameter as a lithium ion adsorbent using electrospinning technique through design of experiment (DOE). Enhanced lithium ion adsorption properties of the HMn2O4 nanofibers with different diameter were investigated in lithium liquid resources."

Jan 1, 2018

"The adsorption of mixed cationic/anionic surfactants with different molar ratios onto quartz was investigated. The cationic surfactant used was dodecylamine bromide (DDA), and the anionic surfactant was sodium oleate (NaOL). The critical micelle concentration values for the individual surfactants and their corresponding mixtures were determined using a platinum plate. The adsorption mechanisms of mixed surfactants on quartz were studied using contact angle measurements, flotation tests and adsorption amount measurements. At alkaline condition, NaOL depresses DDA flotation of quartz without depressing the adsorption of DDA. The molar ratio of mixed surfactants is found to be a key factor in the orientation of alkyl chains and thereby the flotation response of quartz. A mixture of 1/2 or 1/3 DDA/NaOL forms on the surface of quartz when the concentration of NaOL is higher than that of DDA. The adsorption of the mixture decreases the wetting of quartz since the alkyl chains are in chaotically orientation with a conceivable number of head groups directing towards the solution phase. These results provide important insights into the adsorption of mixed surfactants onto quartz surface. INTRODUCTION Froth flotation is known as an effective method of separating mineral particles on the basis of their surface chemistry, specifically their hydrophobicity. [1]. The hydrophobic particles will attach to the bubbles and rise to the top of the containing vessel to form a froth that flows over the lip of the vessel. The hydrophilic particles remain in the liquid [2]. In the process, surfactant is often used as collectors for surface modification in order to change the wetting properties of mineral particles. The primary long chain alkyl ammonium salts are the most widely used as collectors for the flotation of oxide minerals, such as quartz, muscovite, hematite, phosphate and feldspar [3, 4]. Adsorption mechanism of alkyl ammonium salts on oxide minerals has been extensively analyzed [5, 6]. Generally, the ammonium salts are adsorbed through electrostatic interaction of the polar group of the molecules with the surface of these minerals [7]. Despite many obvious advantages of the ammonium salts in low temperature resistance and hard water resisting, however, their unavoidable drawbacks, such as high sensitivity and poor selectivity for slimes, relatively high cost, have limited their applications [8]. In recent years, mixed surfactants have drawn much attention due to their superior physicochemical and surface properties than single surfactants [1, 9-11]. They have been used in many industrial processes such as dispersion/flocculation, flotation, detergent, corrosion inhibition, cosmetics, foods, paints, chemical mechanical polishing, enhanced oil recovery, and nanolithography [12]. Most of the mixed surfactants have synergistic advantage in reduction of the surface tension and critical micelle concentration (CMC); therefore, they exhibit spurious properties, like excellent surface/interfacial activities, and are less expensive than single mixed surfactant systems [13, 14]."

Jan 1, 2016

By M. H. Rauschkolb, J. A. Cremeens

Geotechnical solutions were developed for closure of two historic, remote underground mines in the deserts of southern California. Closure criteria included access closure, minimal site impact, and optimum use of native materials. The closure designs and construction activities incorporated techniques for protecting sensitive biota, particularly bats and desert tortoise. The types of mine openings that were closed include adits, declines, shafts, daylighted stopes, and dugout dwellings. The desert locations permitted implementation of cost-effective closure techniques that relied upon the use of native materials. The strategies and techniques developed for these desert closures are adaptable to other climates.

Jan 1, 2002

By S. Makni, R. E. McIvor

Grate discharges historically outnumbered the overflow type of industrial wet ball mills. However, overflow discharge mills now strongly dominate. In order to understand their comparative advantages and disadvantages, Corem carried out a broad review of this topic. Where the data made it possible, the Functional Performance Equation was used to separate circuit classification from mill grinding effects. Batch tests were conducted in a torque-metered mill at different slurry levels. This paper presents the outcome of these investigations, which is a very strong case for the industry to once again consider grate discharges.

Feb 1, 2023

By R. L. Godfrey

The Custom Coals advanced coal cleaning plant will be designed with a unique blending of existing and new processes to produce two types of compliance coals: Carefree Coal? and Self-Scrubbing Coal?. Carefree Coal will be produced by cleaning the coal in a proprietary dense media cyclone circuit utilizing fine magnetite to remove up to 90 percent of the pyritic sulfur and correspondingly greatly reduce the ash. While may utilities can achieve full S02 reduction compliance with Carefree Coal, others face higher sulfur reduction requirements due to the higher sulfur content of their existing fuel supplies. For these circumstances, a patented Self-Scrubbing Coal will be produced by taking Carefree Coal and pelletizing limestone-based additives with the finest fraction of the clean coal. These technologies will enable over 150 billion tons of non-compliance U.S. coal reserves to meet compliance requirements.

Jan 1, 1995

By S. Chander

The results of an investigation to characterize the chalcopyrite/solution interface are presented. Several techniques including galvanostatic and steady state polarization, cyclic voltammetry and impedance spectroscopy were used. The results show that the dissolution of chalcopyrite is incongruent. Initially, at low potentials(<O.34V), iron species are released which give rise to the growth of an iron-deficient sulfide (IDS) layer. The dissolved iron might reprecipitate as a hydroxide layer depending on solution composition. Continued oxidation involves diffusion of species through the product layer. At higher potentials (>O.48V) further oxidation leads to dissolution of copper and sulfur species with a resultant breakdown of the IDS layer. The changes in properties of surface coatings resulting from various electrochemical treatments are discussed.

Jan 1, 1991

By Xia Guangxiang, R. Y. Wan, Yang Hanlin, M. C. Fuerstenau

The mechanism and kinetics of pretreatment on pyritic gold concentrate with the catalytic oxidation acid leach (COAL) process were studied in the temperature range of 80-100°C and oxygen pressure range of 230-1013 kPa, with sodium lignosulfonate (SL) and mixed medium of sulfuric acid (11 g/[ ]) and nitric acid (5.5 g/ [ ]). The results show that nitric acid acts as a catalyst, the surfactant changes the hydro-phobicity of resulting elemental sulfur to favor the oxidation of pyrite, and the oxidation-determining step would be the chemical reaction between nitric acid and pyrite. When about 80% of pyrite contained in the concentrate is oxidized, the gold cyanidation extraction exceeds 95 % . The nitric acid in solution can be recycled and used again.

Jan 1, 1993

By Suresh K. Bhatt

A mathematically simulated modeling technique is used in this U.S. Bureau of Mines paper to represent a hypothetical mining operation with existing mining technology and prevalent mining costs. Mining scenarios are prepared and evaluated for potential benefits and costs available through computer-assisted mining. Base criteria, parameters, and methodology are described.

Jan 1, 1991

By Summers D. A.

A mining machine has been designed and fabricated to mine coal from room and pillar operations combining high pressure waterjet cutting and mechanical fragmentation. Waterjets are used to slot the coal face with an advancing plow wedge then breaking out larger coal pieces. The machine has the following advantages: - simply built around a disassembled longwall chock and gathering arm loader apron; - few moving parts which are simply and inexpensively maintained; provides immediate roof support in the face working area; - coal produced is larger, with resulting lower preparation cost; - no dust is generated; - risk of spark generation is virtually eliminated.

Jan 1, 1992

By J. A. Botín

Investment decision for large mining projects imply an enormous financial risk and therefore, require a more complex risk evaluation methodology taking into account all sources of uncertainty from each process in the project value chain. Generally, the main sources of risk are those related to uncertainty on grade and other techical variables of the orebody. In this study, conditional simulation is applied to develop a risk management model to quantify and to manage financial risk associated to uncertainty on the grade of the orebody. The model was validated in case study on a real porphyry copper orebody in Chile.

Feb 23, 2014

By Donald E. Zipperian

It has been recognized that froth flotation of mineral particles utilizing rising flow of micro size air bubbles, counter-current to quiescent falling flow of particles in a column type cell, provides a unique mechanical atmosphere conducive to extension of froth flotation process to much coarser and finer particles sizes than possible with mechanically agitated and aerated cells. 1,2,3,4. This paper describes metallurgical results obtained at several plant installations of large capacity commercial size Deister FLOTAIRE® Column Flotation Cells. These cells utilize air aspiration into surface tension lowered water to generate micro size bubbles. Operating costs, power, wear, and scaling characteristics of rougher, cleaner, and scavenger units are compared with mechanical units. Problems encountered and scale up criteria developed when increasing from 0.20m(8inch) diameter pilot cells to 2.42m(96inch) commercial cells are discussed.

Jan 1, 1985

By R. R. Klimpel

The process of flotation is an extremely important solids separation technique employed in a wide variety of industrial process applications. Froth flotation is practiced in the coal industry to recover fines produced during the mining and cleaning of coal. A recent review article by Aplan (1) covers the processing variables encountered in the flotation of coal and the variety of chemicals and operating conditions which affect recovery. Numerous engineering and scientific studies have been performed with the goal of providing semifundamental laws of flotation behavior for improved screening of flotation chemicals, better equipment scale-up factors, etc. Often the results of such work are expressed in the form of mathematical models (e.g. 2, 3, 4, 5, 6) which are potentially useful for evaluating (simulating) on paper such alternatives as possibles process operating or configuration changes, the effects of ore and reagent changes, etc. It appears to be commonly accepted that a complete scientific/engineering characterization of flotation is immensely complicated and not sufficiently developed at the present to accurately predict (or understand) many important industrial facets of flotation. Thus, one is often reduced to detailed experimental characterization in both the laboratory and plant in order to fully evaluate flotation changes or alternatives. It is the purpose of this paper to describe a method of batch laboratory data characterization that is useful in evaluating flotation chemical reagents including froth flotation of coal. The approach consists of running a series of time-recovery curves in a batch float cell followed by the computer curve fitting of this data to a series of mathematical models based on semi-physical reasoning. The unknowns or parameters of these models are then optimally chosen so as to best fit the experimental data. It has been found in both coal and mineral systems that changes in reagent type, concentration, system pH, grind, etc. cause very consistent and logical changes to

Jan 1, 1979

By D. W. Hutchinson

One of the most important problems facing the coal industry today is the disposal of refuse from the coal preparation plants in a safe, economical, and efficient manner while complying with all legal requirements. The most commonly used refuse disposal method has been landfill/impoundment. In this method, the coarser refuse fractions are disposed of by layering and compaction into a landfill. The fine coal slurry refuse fraction is impounded in a dam constructed of a portion or all of the coarser refuse fractions. The failure of an impoundment at Buffalo Creek, Saunders, West Virginia and the sliding failure of a coarse refuse pile at Aberfan, Wales, England, resulted in an evaluation of refuse disposal methods by various regulatory agencies as well as coal producers. The result of this evaluation was the promulgation of Federal regulations dealing with the preparation, operation, and final abandonment of coal refuse disposal areas. As a consequence of these regulations the use of the landfill/impoundment method of disposal became in some cases economically unfeasible or technically impossible. At the time of the promulgation of the new Federal regulations, United States Steel Corporation was in the process of designing the Cumberland preparation plant. As a result of the new regulations

Jan 1, 1977