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By E. Bakhtavar

All parameters influencing the decision for selection of a suitable extraction method were first selected as the base of this study. Then these parameters were categorized in two main groups. The first group of the parameters includes ?geomechanical and inherent characteristics of the dimension stones? such as hardness, RQD, compressive strength, joints plane orientation and spacing, and water content. The second group was named ?technical and economical parameters associated with the investor?s objectives? like for example extraction capacity (production rate), blocks recovery, mechanization, capital investment and operational costs. Finally, the influences of all mentioned parameters on the selection of the most applicable extraction methods have been assessed and discussed.

Jan 1, 2012

By Thomas J. Lien

Granitic Pegmatite deposits are the chief source of commercial feldspar, micas, lithium minerals, tantalum-columbium, beryl, and certain types of kaolin. The output from pegmatite mines in the United States is small compared to other mineral products in terms of bulk or value, and much of it comprises only minor metals and nonmetals. Nevertheless, pegmatite minerals play a vital part in our domestic industrial economy, particularly in the ceramic and electrical industries. Numerous special purpose uses also are important, even though they require small quantities of raw materials. In recent years, realizing the potential importance of the pegmatite minerals, the U.S. Geological Survey, the United States Bureau of Mines, several state Bureaus of Mines, and a few private companies have carried on extensive programs of pegmatite studies in the New England and southeastern states, in the Black Hills area of South Dakota, in the Rocky Mountain region of Wyoming, Colorado, and New Mexico, and in various parts of Washington, Idaho, Utah, Nevada, Arizona, and California. Currently, some of the pegmatite minerals such as micas and spodumene are selectively separated by the flotation process. To a lesser extent a few plants are selectively floating feldspar and quartz. Much of the credit for the above progress goes to the fine work done by U.S. Bureau of Mines (1), and companies such as Foote Minerals (2). Additional research efforts by the New Mexico Bureau of Mines (3) has successfully demonstrated selective separation of micas, beryl, spodumene, lepidolite, microlite, quartz and feldspar from a complex Pegmatite containing all these minerals. Since the nature of the mineralization of various valuable components of a pegmatite deposit is such that selective separation of some of these can be carried out at a coarse size using the Heavy Media Separation technique, it was felt that such a system should be investigated for selective preconcentration of their minerals. It was also felt that of all the :MS systems available, the DYNA WHIRLPOOL (DWP) device which allows a close control and adjustment of specific gravity should provide a means of achieving the above goal. Once the desired preconcentration of one or more of the pegmatite mineral assemblage is achieved, the available selective flotation techniques should provide effective recovery of various minerals into marketable products. This paper presents technical and economic aspects of selective preconcentration of some of the pegmatite minerals followed by selective flotation to produce marketable products.

Jan 1, 1978

By C. A. Carroll

In February of 1989 the Mission Complex of ASARCO Incorporated completed an expansion of its concentrator, raising the base mining rate from 25,900 TPO (28,500 STPD) to 37,200 TPO (41,000 STPD). The expansion was accomplished by extending the twelve existing Mission ball mills in length, by installing the grinding circuit from Asarco's idled Sacaton Concentrator along with various auxiliary equipment, and by modifications to the flotation circuit and water systems. This paper will give a brief history of the consolidation of the ore body which made the expansion possible and explain the various parts of the expansion.

Jan 1, 1990

By T. J. McKeon

Partition curves are used to evaluate the separation performance of gravity-based concentrators. The partition curve is used to identify the nominal density cutpoint and relative sharpness of the separation. In addition, the graphical representation makes it possible to quickly identify the root cause of misplacement based on the characteristic shape of the partition curve. Partition curves have been traditionally constructed using data obtained from float-sink tests using heavy organic liquids. These toxic liquids are environmentally unfriendly and have been banned in several countries. Another method of establishing the partition curve is to introduce density tracers into the feed and plot the distribution to the lights and heavies. For heavy mineral separations, this approach is generally impractical due to the fine particle size. In addition, the partition data obtained using these existing techniques do not account for secondary factors such as particle shape that may influence the separation. In light of these problems, a methodology was developed for constructing partition curves using experimental data obtained from microscopic grain-counts. This technique, which essentially uses the different mineral species as density tracers, provides a powerful tool for evaluating heavy mineral separations. A case study is provided to demonstrate how this analytical approach can be used to assess and improve the separaton performance in an industrial upgrade plant.

Jan 1, 2005

By Jean-Michel Rendu

On April 30, 2003, representatives of the Society for Mining, Metallurgy and Exploration, Inc.(SME) met with the staff of the Division of Corporation Finance of the U.S. Securities and Exchange Commission (SEC). The meeting was held to discuss issues related to the estimation and publication of mineral resources and ore reserves. It took place in the Washington, D.C. offices of the SEC. SEC staff members included Roger Schwall, assistant director, Division of Corporation Finance; Jill Davis, senior accountant; Roger Baer, senior mining engineer; Carl Chavez, chief mining engineer; Ron Winfrey, senior petroleum engineer; and John Murphy, senior petroleum engineer. SME committee members included JM Rendu, independent consultant and chairman of the SME Committee on Resources and Reserves; Ian Douglas, manager of deposit modeling and reserve estimation with Newmont Mining; Art Graham, director and mining engineer with Deutsche Bank Trust Company Americas; Larry Smith, chief geologist with AMEC Mining and Metals Consulting; and George MacDonald, vice president of exploration with Freeport-McMoRan Copper and Gold.

Jan 1, 2003

By G. P. White, J. M. Jones

Computer simtiation is a technique that has beers around for many years. Its applications include designing steel mills, planning space shota, or even developing ways to beat the casinos in Las Vegas. However, the use of computer sirndation in surface coal mining is fairly recent. To promote its use, several government agencies, including the US Bureau of Mines, Forest Service, and Department of Energy, contracted with universities and private companies to develop computer simulation programs for surface coal mining. Some of these developers include McDonnell-Douglas Electronics Co., Pennsylvania State University, Montana State University, Fluor Mining and

Jan 9, 1984

By J. R. Shultz, R. J. Lambert

One of the present trends in the mining industry is the increased use of mining contractors. In the past, many project owners have utilized mining contractors for topsoil stripping or overburden removal, usually on a short-term or periodic basis. In recent years, mining contractors have not only removed the overburden, but mined the product as well. Why is this change occurring? A prevalent trend in the mining industry appears to be the outsourcing of non-core and non-strategic functions, allowing producers to focus more on areas of technical expertise where higher incremental value is added—that is the processing, refining, and marketing of the product. As capital allocation becomes more critical, this trend is likely to continue.

Jan 1, 2002

Talk some about your background. Mining, particularly coal, runs in the family. I come from a mining family, one generation re-moved. Both of my grandfathers worked in the coal mines. My mother?s father had worked as a coal miner in the South Hills area of Pittsburgh after coming to America from Croatia. My father?s father (who died of black lung long before I was born) had been born in America and worked as a mine foreman and superintendent in mines just outside the Pittsburgh area. My father often talked about when, as a child, he accompanied his father underground on Sundays to check the mine pumps. While I never expected to go into mining, I often read some of my grandfather?s books on mining technology that my father had kept. I started college at Penn State and drifted into mining engineering as my third declared major. I was finally realizing the importance of a career choice. I?ve never regretted that decision. One of my children, Mark, has followed me into mining engineering, much to my surprise and pride. Evidently, he had been listening to the many conversations I had with friends and colleagues in the industry and never considered any other career path. He has since married another mining engineer, Kray Davis Luxbacher, so we truly have a mining family and can talk mining when we get together. My other children are in more mundane lines of work and rapidly tire of the mining discussions. I?ve worked for operating companies: Pittsburgh Coal Co. (then a division of Consolidation Coal Co., and a company I believe both of my grandfathers had worked for), Island Creek Coal Co., and a research organization: Occidental Research Corp. I am now with Glenn Springs Holdings Inc., dealing with legacy issues (primarily environmental) related to Occidental?s previous mining operations (coal and minerals). As such, I have a broad view of the industry and the critical changes that are shaping our industry.

Jan 1, 2008

By M. K. McCarter

Surface mining applies to extraction of mineral resources from water and sediments of rivers, lakes, seas, and oceans; from solutions circulating through broken rock and soil; and from rock and soil excavated from the earth. Surface mining is responsible for the majority of mineral production in the United States and a substantial portion of the world?s total production. This section deals specifically with extraction methods which employ mechanical processes in a relatively dry environment to free minerals from the earth. The following section, Section 15, deals exclusively with aqueous methods. With recognition of the importance of reclamation in all activities which temporarily disturb the earth?s ecosystems, it is appropriate to classify mechanical extraction methods as either deferred reclamation or concurrent reclamation. Deferred reclamation is necessary when the shape and logistics of the excavation require that it remain open throughout the productive life of he project. Upon exhaustion of economic reserves, the opening is then reclaimed in a manner consistent with public safety, environmental acceptability, and land use policy. Methods employing deferred reclamation are commonly referred to as open pit or quarry mining. Metallic ores, industrial minerals, and coal are all extracted using open pit methods. Typical examples are provided in Chapter 14.1.

Jan 1, 2008

By S. Chatterjee

Mining represents the first industry in the United States to have federally mandated training for its workers. Although the topics to be covered are specified in 30 CFR 48, course content is left to the discretion of the individual mine operators. Unfortunately, certain topics to be covered, such as prevention of accidents, are usually mine specific, making it very difficult to use the same course content in every mine. Further, training requirements may change from one mine to another, due to changes in the demographic characteristics of the workers, or changes in job and organizational characteristics. Therefore, if the intention of safety training is to modify the behavior of workers, it is expected that there should be some changes in the content of safety training programs in order to address the specific requirements of individual mines, or at least mines of similar worker and job characteristics. This study has been directed towards the development of a systems-based procedure for conducting a needs analysis. A special effort was made to understand the psychology of worker behavior by analyzing worker reactions to various organizational and job characteristics.

Jan 1, 1994

By Steve Kral

The Clinton administration’s policies toward the environment have the mining industry on the defensive. The president and US Secretary of the Interior Bruce Babbitt continue to bypass Congress in their efforts leave an environmental legacy when they leave office in a year. So the mining industry must take its case to the public. And the public seems willing to listen if the industry is willing to tell its story, according to US Rep. Chris Cannon (R-UT). Cannon was one of the keynote speakers at the105th meeting of the Northwest Mining Association, in Spokane, WA. The conference, held in early December, attracted about 2,400 people and more than 200 exhibitors

Jan 1, 2000

By Z. Hyder

Simulation and modeling is powerful tool to analyze real time data and can be used to analyze different scenarios using appropriate software that may reduce need of infield data collection process and can predict reasonably accurate results. In this paper the real time data of a mine is used to simulate and model the stresses on the pillars and evaluate the pillar strength and safety factor. The material properties assigned to the model are obtained by testing the representative samples taken from the selected locations of the mine. The mine under investigation has 50 ft wide pillars and 50 ft wide rooms under an average overburden of 650 feet. The effect of reduced pillar dimensions and increased roof span on overall stability of mine and extraction ratio is analyzed using LaModel [1] software. The predicted results of the reducing pillar size are analyzed to compares the current mining practices with the optimized room and pillar size to get better extraction ratio without comprising the safety.

Jan 1, 2011

By F. J. Klingler, R. Hausmann, K. M. Swaffar, J. C. Neyer

This paper presents the results of a study of case histories of projects on which sinking caissons were used to construct shafts for tunnel construction and other underground works. Design methodologies are reviewed with respect to the impact of soil and groundwater conditions on the performance and constructability of sinking caissons. Factors which have led to success or failure are reviewed and evaluated, and recommendations for future investigation, design and construction activities are presented. Cost data for five recent projects are reviewed and compared to the cost of shaft installation by other means.

Jan 1, 1997

By W. A. Wilkinson

Mining companies today are under increasing pressure to boost output from their existing mines and to bring new projects online quickly. Fundamental to the long-term performance of an operation is geologic modeling and mine planning. To maximize mine profitability, planners and schedulers must account for a staggering array of variables and create accurate mining plans that meet production and profit targets. Not surprisingly, this can be a difficult task, and getting it wrong can result in large unforeseen costs and significant lost revenue opportunities. This paper discusses the top five challenges geologists and engineers are facing in developing mining plans.

Jan 1, 2012

By Don Stevens

The Denali Prospect (147° 08' 20" W, 63° 08' 50" N) is located on the south flank of the Alaska Range in the Clearwater Mountains in south central Alaska. (See Figure 1). The mineralization was discovered in 1963 and surface explora¬tion began the following summer. Surface trenching and diamond drilling were used to locate and sample the mineralized zones. In 1969, an adit totalling approximately 1400 feet was completed. In 1970, a -15% grade decline approximately 1800 feet long was completed. Further diamond drilling was done along with both underground programs. Although much work remains to be done to properly evaluate the prospect, results from all the work to date are quite encouraging. This paper will consider the geology of the prospect and the surrounding area, some- aspects of the geochemistry of the sulfides, and the origin of the sulfide deposits. This paper includes data from this writer's Ph. D. dissertation, "Geology and Geochemistry of the Denali Prospect, Clearwater Mountains Alaska" from the University of Alaska and subsequent work.

Jan 1, 1972

Outokumpu Technology’s HSC Chemistry process calculation software enables the user to simulate an entire chemical or physical process. The HSC Chemistry 6.0 contains 21 calculation modules and 11 databases for reaction, equilibrium, heat balance, heat transfer, petrological and simulation applications. Most of the calculation modules automatically utilize the same extensive thermochemical database which contains enthalpy (H), entropy (S) and heat capacity (C) data. This database has been expanded to include more than 20,000 species.

Jan 1, 2007

By C. Zhou, J. Srednicki

Electronic systems have been increasingly used in underground mines to improve mine safety. These electronic systems emit electromagnetic (EM) energy which can adversely impact the performance of other electronic systems nearby and thus should be characterized. Researchers at the National Institute for Occupational Safety and Health (NIOSH) characterized the magnetic fields emitted from devices that can potentially interfere with the performance of proximity detection systems (PDSs) and compared the emission levels of these devices to the susceptibility of PDSs. In this paper, we present our measurement results pertaining to this effort. Particularly, magnetic fields emitted from the different orientations of a powered air purifying respirator (PAPR) and two lite trackers are evaluated based on the RE101 protocol specified in the MIL-STD-461G standard. The results show that both devices emit strong magnetic fields which strongly depend on the orientation of the devices. At some frequencies, the maximum emission levels from the two devices exceed both the emission limit given in MIL-STD-461G and the maximum magnetic fields that a PDS can withstand without a failure. The results and findings in this paper can help the mining industry better understand electromagnetic interference (EMI) underground and provide critical scientific data that support mining-specific recommendations to address EMI-related challenges.

Feb 1, 2023

By M. R. Shahan, C. E. Seaman, S. E. Mischler, T. W. Beck

"Float dust deposits in coal mine return airways pose a risk in the event of a methane ignition. Controlling airborne dust prior to deposition in the return would make current rock dusting practices more effective and reduce risks of coal dust-fueled explosions. The goal of this NIOSH study is to determine the potential of open-air water sprays to reduce concentrations of airborne float coal dust (<75 µm diameter) in longwall face airstreams. This study evaluated unconfined water sprays in a featureless tunnel ventilated at a typical longwall face velocity. Experiments were conducted for two nozzle orientations and two water pressures for hollow cone, full cone, flat fan, air atomizing, and hydraulic atomizing spray nozzles. Gravimetric samples show that airborne float dust removal efficiencies averaged 19.6 percent for all sprays under all conditions. The results indicate that the preferred spray nozzle is operated at high fluid pressures to produce smaller droplets and move more air. These findings can be used to select sprays and design spray arrays to control airborne float dust over the entire longwall ventilated opening. INTRODUCTION Coal mining processes produce airborne dust that naturally deposits on the floor, roof, and ribs of mine airways. These fine dust particles, termed float coal dust when smaller than 75 microns in diameter, are deposited in return entries of coal mines and can be re-entrained by pressure waves induced by methane-air explosions (Rice et al., 1911; Nagy, 1981; NIOSH, 2006). These particles are also those most likely to participate in coal dust-fueled explosions, which can potentiate and propagate explosions resulting in extensive damage. In order to meet compliance requirements of at least 80 percent incombustible content in the composition of material deposited in mine entries (CFR, 2016), coal mines apply an inerting agent, specifically, rock dust (Harris et al., 2009). Should methane be present in the mine atmosphere, the required fraction of incombustible content is further increased by 0.4 percent for each 0.1 percent methane. The removal of airborne float coal dust (AFCD) prior to deposition is an approach intended to make current rock dusting practices more effective by increasing the proportion of inert material to combustible material, resulting in a lower risk of coal dust-fueled explosions. Water sprays are both effective and widely accepted as a method for controlling underground coal mine dust. In fact, water sprays are considered to be the most economical and technically feasible means of reducing dust concentrations in underground coal mines (Courtney and Cheng, 1977; Barker and Humphreys, 1996). Sprays are used in several ways to control dust in mining processes: inhibiting dust formation, immobilizing dust to prevent it from becoming airborne, and capturing airborne dust (Cheng, 1973). Reductions in airborne dust concentrations have frequently been attributed to inertial impaction between water droplets and dust particles, forming larger agglomerates which then quickly precipitate out of the airstream (McPherson, 1993). Inertial impaction activity is generally accepted as the major capture mechanism for airborne particles larger than 0.5 µm in diameter. It is this mechanism that is evaluated in this study."

Jan 1, 2017

By Kanhaiya Mishra, Phanil. K. Mandal, S. K. Behera, P. S. Paul, Prashant Singh, C. N. Ghosh

The techno-economic and social benefits of cemented paste backfill (CPB) resulted in its wide acceptance by the mining industry. The Ordinary Portland Cement (OPC) remains the key binder but to diminish its economical constraints, suitability of alternate binders has been examined worldwide. The present study aimed to investigate the effect of partial replacement of OPC with fly ash on the CPB’s strength and to determine the most optimal mix to achieve the required strength (1 MPa at 28 days of curing) at the most cost-effective way using the Bayesian network (BN). The CPB mixes were prepared at 72 wt.% solid concentration with mill tailings (87–91%), OPC (6–13%), and fly ash (0–4%), and instantly after mixing, fresh (slump, bleeding, density) CPB properties were measured. The strength was tested at 7, 14, 28, and 56 days of curing and initially analysed through traditional model. The traditional models follow the aleatory principle and are considered not appropriate for geotechnical engineering. Hence, the BN model was developed and tested. The reliability of two classifiers in learning model structure was compared which gives Naïve Bayes as the highest reliable tool. The CPB’s strength is most sensitive to the OPC content. The most consistent mix(s) is mill tailings: 87–88%, OPC: 9–11%, fly ash: 1–4%. Adding fly ash at 89–91wt% mill tailings possesses high failure probability of the CPB. The collinearity test indicates that the fines percentage and chemical composition of CPB’s ingredients are highly correlated with its slump, bleeding, and strength development.

Jul 14, 2022

By Katzer R. Klimpel, J. Sewell

Dr. Roussey Roussev The use of chemical additives on grinding is of significant importance considering the high energy consumption of grinding processes. My research indicates that the dispersant approach explains the effects, in this particular case of wet grinding. Further, the dispersant approach combined with torque measurements give the possibility of clarifying the mechanisms involved when using grinding aids. I find the conclusions derived from the data obtained to be correct and useful for grinding. In general, I agree with the explanations. However, I would like to discuss several additional points that I consider to be important, and in the same time to mention some of my own results from investigations similar to those presented in the study under discussion. The "bed volume concept" and the change of slurry viscosity explain adequately the data plotted on fig. 3, in conjunction with Figs. 1 and 2. However, the significant increase of the average torque in the case of 83% solid with XFS-4272 introduces the necessity of establishing the optimum of percent solid when dispersant is used. For example, the optimum percent of solid for different materials varies. One of the reasons is the material&apos;s mass density. On the other hand, it is necessary to determine the concentration of the chemical used. Because of this, it would be interesting to know how the cited concentration was selected. The supportive discussion and verification by Dr. Roussev, with results similar to that of the paper, is appreciated. I will try to answer the additional questions he has raised. To begin with, the mill was fitted with six lifters of approximately one-quarter inch height. There has been extensive lab and plant level work to understand downstream influences of using dispersants like XFS-4272*. In sulfide ore processing, which is the area in which most industrial scale testing has been performed with this approach, neutral to positive influences have been observed. For example, positive effects (e.g., increased recovery) have been noticed in flotation operations involving ores that have a tendency to produce excessive slimes upon grinding. (1) Also, the use of a dispersant has been shown to demonstrate a positive influence on classification by improving the sharpness of separation and preventing a decrease in d50 value that usually accompanies increasing flow rates to classifiers.(2) The biggest potential downstream problem is in thickening, which at the dosages involved, has not been a problem in plant scale usage. The commercial price of dispersants like XFS-4272 is quite variable depending on source, concentration, etc, but a typical cost of XFS-4272 to achieve a 10% increase in throughput in industrial mills has been between 20 and 35- US per ton of feed ore (1981).

Jan 12, 1982