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Production In 1993, it was estimated that United States mine production of barite increased 24%. Barite consumption, either sold or used by grinding plants, increased by 39% and imports increased 4%, according to the US Bureau of Mines (USBM). Nevada continued to be the leading producer of barite with 80% of the total, followed by Georgia. It is estimated that 83% of the domestically mined barite was used as a weighting agent in drilling fluids. The remaining 17% was used in barium chemicals, glass or as a filler. Most of the production from Missouri, Georgia and Tennessee was used in the non-oilfield sector. Prices The value of domestically produced barite, f.o.b. mine, decreased 1%, according to the USBM. The declared value c.i.f. US port of all imported crude barite during 1993 decreased from $40.09/t ($36.37/st) in 1992 to $37.72/t ($34.22/st). Uses Of the total barite used by grinding plants and chemical manufacturers, it is estimated that 90% was used in drilling fluids and 10% in the non-oilfield sector. This included barium chemicals, fillers in paper, plastics, brake shoes and glass. The tonnage consumed in the drilling fluids market increased due to the higher average rig count during 1993. The average number of rotary rigs operating in the United States was 754, 5% greater than the 1992 average of 717. Imports Crude barite imports in 1993 were 443 kt (488,000 st) greater than 1992, representing an increase of 137%. Imports accounted for 67% of the barite consumed (apparent) in the United States.

Jan 1, 1994

By S. J. Stokowski

An extensive drilling and laboratory testing program indicates that diagenetic dolomitization of the Oligocene Sombrerito Fm. limestone, southwestern Dominican Republic, is detrimental to the usefulness and quality of the potential construction aggregate resource. The first part of this program was the collection, photographing, and geologic logging of diamond drill cores to allow lithologic subdivision of the strata into potential quarry layers. The primary lithostratigraphic units are: I (youngest) approximately 10 m of white, dense marine limestone; II, approximately 5 m of white, interbedded dense and chalky marine limestone; III, 2+ m of tan, chalky calcitic dolomite. Unit I has been often altered by lateritic weathering and/or dolomitization; Unit II is often altered by dolomitization. The quarry layers were individually crushed, by core, into coarse aggregate sizes for chemical and physical (specific gravity absorption, MgSO4 soundness, sand equivalent, and LA degradation) analyses. The non-weathered units decrease in coarse-aggregate yield and quality with depth and dolomitization. Dolomitization typically causes about 5% lower yield of coarse aggregate, a sand equivalent of about 20 units below the original value, an increase in absorption of about 3%, an increase in the LA of up to 13%, and a decrease in the average 5-cycle MgSO4 soundness by about 17%.

Jan 1, 1987

By Brij M. Moudgil

Separation of dolomite from apatite, because of nonselective adsorption, cannot be achieved by conventional froth flotation technique. Results obtained in the present study also indicate, that this can be attributed to the depletion of the collector molecules due to complexation with the calcium and magnesium ions, dissolved from the two minerals. However, it has been established in this investigation that conditioning the material at pH 10, followed by reconditioning, without any additional collector, at pH 4, results in selective flotation of dolomite from the mixture. The recovery of apatite, in the proposed reconditioning process, is much higher than with the conventional conditioning under similar pH conditions. The mechanisms involved in the conventional conditioning, and the reconditioning process are presented.

Jan 1, 1983

By M. Buxton

Sensor derived data can add value across the mining operating chain ranging from resource definition, extraction, pre ? concentration, mineral process monitoring and assessment of product quality. Most documented studies on the use of sensors in mining focus on specific technologies for specific applications. These studies do not take into account different aims, objectives and operating conditions at different steps in the value chain. The first part of this contribution assesses key physical performance and discriminatory requirements of sensors applied in each portion of the mining value chain. The second part proposes a framework of methods for quantifying the value added by additional sensor information. Integrating the sensor based technology and the economic value quantification allows for both, designing an economically optimal sensor monitoring network along the whole mining value chain and optimizing efficiencies. Illustrative studies demonstrate the significant economic benefits, in particular in reduction of exploration expenditures, increase in extraction efficiencies, increase in ore product quality and improvement of processing efficiencies.

Feb 27, 2013

By Robert M. Belesky, H. R. Hardy

A methodology to detect the presence and monitor the stability of shallow cavities is presented in this paper. The approach incorporates surface-wave seismic and acoustic emission/microseismic (AEIMS) techniques. Application of tomography to the seismic data is made to enhance the ability to locate cavities. Zonal and hit-sequence location techniques are introduced into AE/MS monitoring schemes. These source location techniques simplify the analytical procedure yet still provide sufficient information regarding the region of AE/MS activity. The concept of unique velocity data for conventional, least-squares, source location routines is discussed. A hypothetical case utilizing the algorithm is presented. The method described has been successful based on preliminary studies. Areas of current and future research are identified.

Jan 1, 1986

By Hal McVey

"Philosophy" addresses the definition and assigning of importance to the marketing of by-products. Two examples, one in metals and the other in industrial minerals, explore prime product to by-product relationships. Relative revenues from all products illustrate the importance of by-products to economic feasibility. "Mechanics" takes a broad view of the types of marketing organizations that are applicable to individual circumstances in the marketplace. In-house marketing as well as agents, merchants and trading companies are outlined and discussed. Philosophy Definition Of Terms Philosophy Definition Of Terms The definition of terns for a paper such as this is generally a necessary but not-very-interesting exercise. However, in simply trying to clearly define the term "by-product" some interesting relationships between products arise and the line of demarcation between "product" and "by-product" often becomes obscure. The search for that distinction represents the philosophy portion of the title. A couple of definitions of philosophy can even help to set the tone for what follows. According to Webster, philosophy is : 1 Pursuit of wisdom. 2. A search for a general understanding of values and reality.

Jan 1, 1983

By Marc. A. Meyers

The analysis of the phenomena involved in the determination of the compressive strength of iron-ore agglomerates leads to the identification of the important parameters. It is shown mathematically that the pellet rupture strength is proportional to the cross-sectional area. Fracture is initiated at the center of the pellets by the tensile stresses developed by the compressive loads normally to the compression axis. The variation in strength between individual pellets of identical composition and subjected to identical treatments is due to internal voids of varying sizes, that act as stress-concentration sites. Two novel testing procedures are proposed. The first consists of testing the pellets between two plates having three steel spheres each. This configuration simulates much better the environment actually encountered by the pellets. The second procedure consists of a thick-walled cylinder in which a piston penetrates; a large group of pellets is tested simultaneously, as the stress versus strain plot is being recorded. This latter test presents significant advantages over the conventional testing procedure; the main one is that one single test is sufficient to characterize the mechanical response of the pellets.

Jan 1, 1981

By W. F. Moll

Absorbent clays are products, usually in the form of granules, that can absorb and hold approximately their own weight of liquids while essentially maintaining their size and integrity. They always contain in abundance at least one of three materials: montmorillonite, attapulgite and diatomite. The first two are complex silicates; the last is amorphous silica of biogenic origin. Not all montmorillonites provide the base for an absorbent clay, however. Nevertheless, the silicates in particular, and the diatomite to a lesser degree, have certain molecular properties that give rise to the useful physical properties. Uses Use of absorbent clays is as old as civilization. Numerous references to "fuller's earth" appear in ancient writings, including the Bible. Fuller's earth originally connated a clay that could absorb oil and grease from wool to facilitate cleaning. Robertson (1986) covers the fascinating history in interesting detail. In the modern sense, absorbent clays find application in three principal areas, and a host of minor ones. Industrial floor absorbents, cat litter and agricultural carriers comprise the major uses.

Jan 1, 1986

By Paloma Lazaro, Moe Momayez

Heat-related illnesses (HRI) are relatively common in both hot surface and underground mining operations. When workers are exposed to extreme heat or strenuous work in a hot environment, they become prone to heat stress. Heat strain is the result of the body’s response to external and internal heat stress. It is therefore vital for the conditions leading to heat strain be detected and treated in a timely manner. Heat-related illnesses are manifested by exhaustion and heat stroke. The predicted heat strain (PHS) [ISO 7933 (2004)] model has been developed to predict the health condition of the worker in terms of core body temperature and water loss. The PHS model tested in this study is based on eight physical parameters that are measured at different intervals during a work shift. They include air temperature, humidity, radiation, air velocity, metabolic rate, clothing insulation, posture, and acclimatization. The model predictions are then compared with a direct physiological measurement, such as core body temperature. We present the results of an extensive study that monitored and predicted body’s response to heat stress under different environmental and working conditions. The PHS model provided reliable results in most instances in comparison with other prediction methods currently in use in the field.

By B. Samoski

In late 1994, EPA and OSM acknowledged that efforts by any one agency or by the many different agencies to remedy the water quality impacts of decades of contamination from abandoned coal mine lands in Appalachia would not be successful if their disjointed efforts were not unified and if the local watershed organizations were not included. The result of the collaboration between EPA and OSM was the creation of a statement of mutual intent which was a pledge by government agencies, watershed organizations, and the industry to restore watersheds degraded by acid mine drainage from abandoned coal. The presenter will describe the evolution of this pledge from a paper promise to on-the-ground remediation projects.

Jan 1, 2002

By G. Abramov

The 20th Century saw the modern mining industry enriched by one outstanding method of extracting of mineral resources called Borehole Mining (BHM). Mean while, despite its successful track record in wide ranging locales, few specialists are yet aware of this technology. The intent of this article is to introduce borehole mining to a wider spectrum of drilling and mining professionals. The BHM method is based on in-situ water jet cutting of rock mass. On Fig. 1 the schematic of the method is presented. The borehole mining tool 1 is lowered into the borehole 2 and high pressure water 3 is pumped down. At the bottom part of the tool, one portion of that water comes out through the hydromonitor nozzle 4 in a shape of water jet 5 and cuts the material 6 creating slurry 7. The other portion of high pressure water then comes to the hydroelevator 8 (jet pump, eductor) which produces a vacuum. When the slurry reaches this vacuum zone, the eductor sucks the slurry and pumps it up to the surface, where rock parts are separated from water in a tank 9 or a pond and clarified water is pumped down again closing the re-circulating BHM water supply system. The borehole mining tool is suspended on a drill rig tower 10 which allows the tool to rotate and move vertically along the borehole axis. While extracting rock mass, underground caverns (stopes) 11 are created. If necessary, compressed air 12 can be injected to the raising slurry flow to create an airlift effect. Also, a secondary agent 13 (such as oil, foam, etc.) can be added to the stope through the gap between the tool and the casing. As seen from the illustration, BHM is the remote mining method of extracting of mineral resources through boreholes by high pressure water jets.

Jan 1, 2001

By G. M. Wilemon

The U.S. Bureau of Mines has conducted investigations on extracting phosphate values from wastes generated during the mining and beneficiation of phosphate matrix. These wastes may contain up to one third of the phosphate originally present in untreated ore. Samples of wastes were air-dried and leached using 93 pct sulfuric acid in the presence of methanol. Evidence for the formation of a calcium sulfate hemihydrate coating that hinders complete dissolution of phosphate is presented. Solid-liquid separations were enhanced when flocculation was effected using poly(ethylene oxide) (PEO) in conjunction with hydroxypropyl cellulose (HPC) or hydroxyethyl cellulose (HEC. A conceptual flowsheet for a proposed process using an acid-alcohol leaching technique is presented.

Jan 1, 1990

By Sergey G. Pushkin, Eugeny L. Schastlivtsev, Anatoly A. Bykov

Three years ago the authors and a group of assistants began to develop a GIs-system for integration of comprehensive eco- logical information to be linked to geographical maps of Kuzbass region. And now we have got the working system and some first results that the present paper deals with.

Jan 1, 1996

By Lance Rasband, Richard Hanke, John Starcevich

"The world’s largest tunnel boring machine (TBM), at the time of her launch in 2012, the TBM locally referred to as “Bertha,” is incapacitated due to mechanical failure. Bertha’s stoppage places her 25m below the surface between the aged Alaskan Way Viaduct and the failing Seattle Seawall. Accessing Bertha with a vertical shaft provides the best approach to access all facets needed for repairs and will allow the full removal of Bertha’s cutter head and related inner workings. Due to the limited area above the tunnel alignment and physical constraints created by existing infrastructure, the dimensions of the otherwise symmetrical shaft are heavily impacted, thereby requiring special attention to design and layout. Consequently, the shaft design required a combination of 3m, 2.5m, 2.2m, 1.5m and 1m diameter unreinforced drilled secant piles coupled with various ground improvement techniques and dewatering, to fully satisfy the shoring design requirements. This paper will describe the shaft installation procedures, equipment used and pitfalls encountered while undertaking access shaft construction of this magnitude. INTRODUCTION Mining on Seattle’s SR99 tunnel began in July of 2013. Initial mining progressed slowly through a 4.5 m thick fiber-reinforced concrete headwall before immediately entering the first of three planned safe havens. Once through the headwall and safe haven the machine would move through roughly 122 lineal meters of jet grout improved soil at a rate of slightly over 1.6 m per day. It was anticipated that once mining has passed through the improved area, “Bertha” – now the world’s 2nd largest tunnel boring machine (TBM), would be moving at a rate of almost 11 m per day. By the end of October 2013, Bertha had mined roughly 131 m, averaging 1.4 m per day, and had begun mining within native soils. By the start of December 2013, tunneling had reached the 244 m mark and Bertha was now averaging 3.6 m per day, achieving as much as 12.8 m of progress on given days. Unfortunately, on December 6th, 2013, Bertha began to stumble and all progress quickly came to a halt. Initial reports stated an obstruction had stopped Bertha in her tracks. The preliminary investigation involved installation of 10 deep dewatering wells to reduce the hydrostatic pressure within the ground around the TBM, to allow the contractor’s personnel to inspect the cutter head from within and also to investigate for the presence of obstructions at the face of the cutter head. During inspection, the contractor’s crews found fragments of steel pipe entangled in the cutter head. The steel was apparently from an abandoned 254 mm diameter monitoring well casing, previously installed by WSDOT to monitor ground water conditions for the design and planning of this tunnel project. After the steel was removed from the cutter head and cleared from Bertha’s path, she attempted to move forward but was only able to generate a slow crawl."

Jan 1, 2016

By J. D. Miller, C. L. Lin

As the techniques and resolution for three-dimensional spatial analysis have advanced in the last decade, it is now possible to map in detail the microstructure of multiphase materials in three-dimensional digital space. In this regard, three-dimensional X-ray microtomography offers a unique imaging capability. Spatial resolution on the order of 10 µm can be achieved with the use of microfocus X-ray generators. Recently, a state-of-the-art cone beam X-ray microtomography system was installed at the University of Utah for the quantitative analysis of multiphase materials in three dimensions. This facility was designed to obtain 2,048 by 2,048-pixel reconstruction over a 10-mm diameter, while also allowing for the imaging of somewhat larger (40-mm) objects. The system is capable of handling high-density materials, even materials having a density as high as 8.0 g/cm3. This unique, one-of-a-kind instrument can be used to obtain three-dimensional spatial reconstruction for many applications, such as three-dimensional liberation analysis, pore structure analysis of particle beds during filtration and the air-void system of concrete structures. The utilization of X-ray microtomography not only allows for the quantitative analysis of multiphase systems but also allows, for the textural characterization and determination of phase continuity. This paper presents information regarding the current use of this new facility and a review of potential applications for the advanced analytical system. Key words: Cone beam X-ray microtomography, Three-dimensional analysis, Material characterization

Jan 1, 2003

By William G. Fischer

Equations developed by an early researcher in subsidence, F. Martos of Budapest, Hungary, have been slightly modified to produce effective equations for predicting the time-dependent nature of Green River trona mine subsidence. Following the initial study, a survey was run to check the results twenty years after mining of the area had been completed. The final results were within a few centimeters of the value that had been projected. Mining conditions in the Green River area are ideal for this sort of study with trough type subsidence being the surface manifestation of high extraction underground room and pillar caving operations.

Jan 1, 1986

By K. C. Carriere

INTRODUCTION The purpose of this paper is to introduce the reader to basic control strategies for solid/liquid separation in mineral processing and to indicate some of the implementation difficulties to be encountered, without becoming overly involved in details of process, equipment or software. It is assumed that the reader has some familiarity with control systems and with dewatering processes, since exploration of these topics would require considerably more length. The paper is organized into three parts: first a general discussion on the need for control of dewatering processes and of the general criteria involved, next a more detailed elaboration on control strategies for the various unit operations, and finally a case study showing a specific approach towards such a project. Motivation & Objectives The justification for implementing any control system in an industrial plant is to improve operations and thereby to increase profitability. Without this motivation, the system will likely be perceived as unnecessary and will decline into disuse, an expensive and troublesome monument to someone's ill-conceived ideas. However, when a control strategy is correctly conceived, implemented and integrated into operations, it can provide significant advantages in operating ease and efficiency, and a handsome return on investment. In general terms, the objectives in establishing a control system are: • stabilization of process disturbances maintenance of product quality • maximization of throughput • dearer definition of process • protection of personnel and equipment A successful control strategy must address at least some of the above criteria. However, the most important requirement is a commitment on the part of plant personnel and management to start up, operate and maintain the system, and to upgrade it to reflect current process status and operational philosophy. Process Applications In this paper, control strategies will be explored for the most common methods of dewatering of mineral pulps. These unit operations include: drying, centrifuging, filtering and sedimentation. While the first three are important, they do not tend to be as complex as sedimentation, and thus will not be as exhaustively treated. Sedimentation is very widely applied, not

Jan 1, 1986

By G. Davey

High speed stirred milling is a relatively new method of grinding in the metalliferous process industries. However it has been it has been in wide spread use in the industrial mineral field for over 30 years for various minerals. Many existing metallurgical operations are looking to maximize economic return from existing deposits, requiring new thinking and technologies. The operating experience of two existing copper operations will be covered to show the effect of the introduction of the Metso Stirred Media Detritor (SMD) a new type of high speed stirred mill. Both operations have derived significant metallurgical benefits from the introduction of this new technology. The benefits and process difficulties are covered and explained.

Jan 1, 2003

By Edward C. Krug

"You are to use the word ... purely for its selling power. It is a name they venerate. As a result, you can use the word ... to ... get [them] to practice, not only without shame bit with a positive glow of self-approval, conduct which, if undefended by the magic word, would be universally derided." (C.S. Lewis, The Screwtape Letters, 1982, p. 162). "We need to tear everything down over a period of time and reconstruct a whole new world, planned top to bottom. "Right now there are just way too many people on the planet [5.3 billion]. `If we had ... an ethic ... we could cut back to 250 million-350 million people. `The United States is ... a bunch of pigs ... the average citizen ... [uses] maybe 70 to 80 times as much as anyone in the Third World.` "The indigenous pople were the ones that were right! I mean, they had their own religion, their own ethics and their own technology. We just went down a wrong road. "So when he says, `We got to rebuild the whole world,' you have no doubt this is serious sentiment .... And it is finally this world view that distinguishes (Ted) Turner as a media mogul and an environmentalist. It is why Worldwatch's Lester R. Brown told me Turner was `truly a visionary. "'(Interview of Ted Turner, Audubon magazine, November-December 1991. On Dec. 28, 1991, Ted Turner was name Time magazine's "Man of the Year." Clearly, media and environmental leadership agree with Turner's openly stated beliefs.)

Jan 1, 1992

By Glenn A. Gruber

The conditioning of phosphate flotation feed with anionic flotation reagents was identified as a high- priority research topic during a beneficiation work- shop sponsored by the Florida Institute of Phosphate Research (FIPR). FIPR subsequently solicited research proposals to identify the mechanisms of reagent adsorption, to determine scale-up relationships for conditioner design, and to investigate the effect of conditioning variables on reagent adsorption and flotation performance. The two-year research project was awarded to Jacobs Engineering. Somasundaran, Inc., the University of Florida Mineral Resources Research Center, and the U.S. Bureau of Mines assisted Jacobs. Two mechanisms of anionic collector adsorption were detected by spectrographic analyses and confirmed by microcalorimetric measurements. The mechanisms provided a sound technical basis for the empirical practice of conditioning phosphate flotation feed at a high percent solids. Tests performed in laboratory and pilot-scale agitated tanks indicated that power intensity may be used as a reliable scale-up parameter for anionic conditioning of phosphate slurry. Excessive agitator speed during conditioning was found to be detrimental to anionic flotation performance. Some dimensional ratios of anionic conditioners were found to be consistent with good utilization of agitation energy. Laboratory conditioning and flotation tests demonstrated that adsorption of collector onto phosphate and the subsequent recovery of phosphate in anionic flotation were significantly influenced by the quantity and quality of water used in conditioning. Conversely, the quality of water used in flotation was more influential on the recovery of quartz in the concentrate. A comprehensive survey of anionic conditioners and conditioning practice in the Florida phosphate industry was also performed during this project. The study clearly showed that flotation testing with laboratory conditions typical of scientific research gives different results than laboratory testing with simulated plant conditions. The effects of test conditions on laboratory test results should be carefully considered by investigators planning and conducting applied research.

Jan 1, 1999