Search Documents

By F. E. du Plessis

"The distinction between data suitable for process control and data subject to aliasing only becomes quantifiable with the availability of rapid real-time measurements. Expecting the dynamics of flotation to vary for different ore types, process flows and equipment types; a study was conducted to compare the dynamics of different flotation processes. The results shed light on the critical sampling intervals required for process control which in turn allows process stabilization and optimization. The technology used for the in-line measurements is based on diffuse reflective spectroscopy and has been introduced into the mineral processing industry over the past ten years. It has been widely implemented in the sulphide flotation industry in South Africa for the real-time measurement of grade.BACKGROUND AND OBJECTIVE A study was conducted by Du Plessis and Keet (2010) to quantify the minimum sample frequency required for grade and/or impurity control. The study was based on chromite data collected at 15 second intervals from the concentrate line of a flash float cell in the Platinum industry. The data captured the natural process variation of the entrained chromite through water recovery due to changes in feed parameters and flotation performance. It was found that the minimum rate of sampling required from the studied flash float concentrate was 2 minutes. This sampling interval time accounted for 90% of the variance in the process data. It was further found that a sampling interval time of longer than 4 minutes produced data with no significant correlation to reality. The dynamics of the flotation process has been misjudged in the past but can be quantified with the availability of real-time grade measurement based on diffuse reflective spectroscopy. The objective of the study was to compare the dynamics of different sulphide flotation processes through the comparison of maximum sampling interval times required to combat aliasing. All data were collected from single stream analyzers that are currently installed at mineral concentrators. The technology used is based on diffuse reflective spectroscopy."

Jan 1, 2012

By A. J. Basu

An overview of the evolution of computerized mine planning and design has been given, emphasizing the need for a knowledge-based system for planning and design of underground coal mines. An outline for the development methodology and procedure has been provided. Problem structuring guidelines have been used to incorporate intelligence and integration to the design modules. A skeletal model for a mine planning and design expert system has been prescribed, and the development process has been documented in detail. A feasibility prototype has been developed to test the structure of the skeletal model and to ensure completeness of the design process. The feasibility prototype development and its contribution toward proto typing has been addressed in this paper. At present, prototype development is underway. The prototype is expected to be avail-able for testing and implementation in early 1991.

Jan 1, 1991

By R. A. Hill, J. D. Pitts

"Long distance slurry pipeline systems have been successfully trans-porting steam coal, iron concentrates, copper concentrates and limestone for an aggregate of nearly 60 years and nearly three billion ton-miles annually. A phosphate concentrate pipeline is nearing start-up and systems for coking coal, lead/zinc concentrates and fly ash are planned. The solids pipeline concept, first patented in the early 1900's and commercialized in the 1950's, is now a proven technology providing an economic, environmentally pleasing and safe method for long distance bulk transport.The challenge for larger tonnage and longer distance movements of solids, for traversing increasingly rugged terrain in grass roots mineral developments, for transporting untried materials and for shipping more economic forms of proven materials still remains. This has necessitated continued refinements and optimization of the technology. The economic and environmental incentives for slurry pipelines when compared to other transport alternatives has justified substantial activity in this area. The scope of planned systems in coal, iron and other minerals is indicative of the firm place slurry pipelines will have in worldwide mineral development.In this presentation, the state-of-the-art in long distance slurry pipelines is reviewed with a focus on major systems of interest to the mineral processing industry. An overview of new developments in the application of this concept is presented, and finally, a projection of the future of pipelines in mineral development both worldwide and in Canada is discussed."

Jan 1, 1978

By Rudolf E. Greuer

It is undisputed that an interaction between mine fires and mine ventilation systems exists. The ventilation carries the poisonous and sometimes explosive combustion products, which constitute the greatest danger of mine fires, through the mine and it provides the oxygen on which the intensity of the fire depends. The fire, on the other hand, can produce considerable ventilation disturbances which make it difficult to predict the path along which the combustion products travel. The opinions, how serious a threat such fire generated ventilation disturbances are, vary. Where shallow deposits are mined and brisk ventilation currents are used, it is frequently felt that these disturbances are of no serious concern. Where mine workings extend over larger elevation differences and where such disturbances have been encountered and been the cause of some larger disasters, their assessment is an integral part of all fire emergency plans. The author felt that the potential of digital computers for the design of ventilation emergency plans, contrary to their acceptance for conventional ventilation planning for more than two decades, is not yet fully utilized. He designed a program for the simulation of ventilation systems under emergency conditions in particular fires. This was part of work completed for a contract with the U.S. Bureau of Mines ( Open File Report OFR 115(1)-78)

Jan 1, 1980

By WU Jian-hui

Keywords: metallic material, precursor synthesis, precipitation, nickel, fibrillar powder The composition and morphology of the precursor of fibrillar nanocrystalline nickel powder prepared by oxalate precipitation are characterized by XRD,IR and SEM analysis, and the effects of temperature, nickel concentration, pH, surfactant and drying process on the morphology and the dispersion of the precursor are investigated. By the experiment results, the fibrillar precursor is a complicated nickel salt. The precursor prepared in the of 60~70°C,0.6~0.8 mol/L nickel ion, pH=8.4~8.6 and with addition of PVP surfactant is well dispersive and in fiber form. The powder dried by azeotropic distillation is dispersive.

Jan 1, 2005

By S. J. Schatzel

In order to better understand the effects of longwall mining on the methane reservoir overlying the panel, the National Institute for Occupational Safety and Health/Pittsburgh Research Laboratory (NIOSH/PRL) designed and implemented a vertical borehole monitoring experiment (BME) on an active longwall panel. The mine operates in the Pittsburgh Coalbed in Greene County, Pennsylvania. The BME site was located away from either end of the panel to avoid mechanical influences caused by the draping of overburden in this region and was positioned at the same distance from the tailgate gateroad as the mine?s gob gas venthole sites. The borehole drilling depths and monitoring intervals were chosen to address a different stratigraphic zone in each of the three planned holes. The monitoring boreholes were positioned perpendicular to face advance using a close spacing pattern of about 15 m (50 ft) between collars. Boreholes were instrumented downhole and on the surface for various measurements. It was observed from the field data that the gob gas venthole fracture network formed 24-46 m (80-150 ft) ahead of the mining face. Overburden permeability?s within the same test zones increased 100 to 500 times following undermining. The borehole test interval within the fractured rock responded to overburden gas pressure while the test interval in the caved zone responded to mine ventilation conditions. Eight months after the boreholes were undermined, slug testing indicated permeabilities had increased further in the fractured rock zone. Measurements of surface movement indicate that the permeability development observed in the boreholes is a product of vertical subsidence without lateral movement within the tensional rock mechanics zone on a supercritical longwall panel. Results from this study suggest that maximum permeability in the longwall panel overburden is achieved 58 to 190 m (190 to 620 ft) behind the longwall following maximum compaction of the overburden.

Jan 1, 2009

In 1962, minerals beneficiation showed definite signs of coming out of the doldrums into which it has drifted after the uranium boom. Demand by steelmakers for high-grade iron pellets has created the need for concentrating plants to upgrade specular hematite by spiral concentration or flotation and magnetites by magnetic means and flotation. According to a paper given at the AMC annual meeting by C. S. Arms of Pickands Mather, "the shipment of pellets, started in the mid-1950's, has increased to 17.6 million tons in 1961 from North American operations. Many plants already underway will raise this production to about 42 million tons by 1965. This will be a very sizeable percentage of the total iron ore production contemplated by that date." Iron ore concentration methods are gradually raising the assay of pellets into the 65 to 69% Fe range and lowering silica to the 4 to 7% range. Quebec Cartier's Lac Jeannine concentrator went into operation in late 1961 and all grinding units were running by 1962. The Iron Ore Co. of Canada's new Carol Lake plant was started in mid-1962.

Jan 2, 1963

The sulphide ores of the principal lodes of the Boulder Mines are mainly composed of a schistose guess with a varying proportion of silica and lime, containing tellurides of gold, silver and mercury, associated with iron pyrites. It is a great difficultyto obtain pure and homogeneous samples of the tellurides for analysis, and from a number of tests made with excellent specimens it was found hardly possible to procure two to agree in analysis, the precious metals being found to be combinedwith tellurium in most varying proportions indeed, a close inspection of a partially crushed specimen will reveal, even to the naked eye, the various shades of colour characteristic...

Jan 1, 1901

By D. H. Diering

The paper takes the reader into the depths of a modern ultra-deep South African gold mine and gives a perspective on the vertical and horizontal extent of the tunnel networks in such a mine. Depending on the mine design layout employed, tunnels once excavated are subjected to various levels of stress change over their life time, and the support requirements are explained. It is suggested that shotcreting is the only viable ultra-deep level support medium, and after looking at the latest developments, the logistical problems are put forward. In an effort to overcome most of these problems, the South African ultra-deep mining industry embarked on a collaborative research programme in 1998. The importance of tunnelling and in particular tunnel support as a critical technology for future successful ultra-deep level mining is stressed. While not yet fully ?on top of? these problems and challenges, our industry is now fully addressing them and we expect to make significant progress during the next 4 to 5 years.

Jan 1, 2000

"The Dumont deposit is a large (1066 Mt probable reserve) low grade (0.27% nickel), nickel sulphide project located in the Abitibi region 25km west of Amos, Quebec. Royal Nickel Corporation acquired the project in 2007 and has since taken the deposit through pre-feasibility. And updated, revised pre-feasibility was released in July 2012.The disseminated nickel sulphide and alloy mineralization is hosted within the serpentinized dunite subzone of the Dumont Sill; a differentiated, pervasively serpentinized, ultramafic sill of komatitic affinity. Pentlandite, heazlewoodite and awaruite are the dominant nickel-bearing, metallic phases and can be recovered by conventional methods (flotation, mag separation). Non-recoverable nickel is also present within the silicate matrix of the serpentinized dunite and is locked in serpentine (Fe and Mg-rich variants) and minor olivine.A detailed mineralogical program including 1097 QEMSCAN® samples and 4300 electron microprobe points were undertaken to increase the understanding of the nickel deportment in the various recoverable and non-recoverable phases in a spatial context across the deposit. Eighty-three (83) metallurgical tests performed under a standard procedure have linked the mineralogy to metallurgical performance. This has allowed the creation and modelling of geometallurgical domains on a block by block basis to understand the recovery variation and metallurgical performance throughout the deposit. Understanding the spatial variability of Ni deportment in recoverable and non-recoverable phases through mineralogy is the key to understanding metallurgical performance thus, unlocking the value of the Dumont deposit and other large tonnage low grade ultramafic nickel deposits."

Jan 1, 2013

By Ali Mortazavi

In underground mining applications, successful blasting results in less damage, which may lower support costs, lower dilution and produce a uniform fragmentation. The explosive detonation process creates a pressure front that propagates a stress wave into the surrounding rock mass at a high velocity. The stress wave can induce varying degrees of damage, depending on rock strength and physical properties, to the excavated area. This paper presents a summary of a research project that was conducted to investigate the propagation of explosive-induced stress waves in hard rock media and the mechanism of rock damage and fracturing due to shock wave propagation. The primary objective of this work was to numerically simulate the experimental study of blast-induced rock fracturing conducted within Inco Limited, Mines Research department. ITASCA?s discontinuum code UDEC (Universal Distinct Element Code), was used to simulate the results of the controlled blasting experiments. In brief, the focal point of the paper can be summarized as follows: ? Investigate the size of the stress-wave-induced fractured zone around the blasthole, ? Examine the extent and direction of the radial fractures that form outside the blasthole, and ? Explore the mechanisms that cause rock breakage.

May 1, 2002

By H. Britton

This bulletin is the seventh in the series of petroleum bibliographies published by the Bureau of Mines, Bulletins 149, 165, 180, 189, 216, and 220 being compilations for the years 1915, 1916, 1917, 1918, 1919-20, and 1921, respectively. In this bulletin the same general plan of classification of references has been followed, but several additions have been made. ACKNOWLEDGMENTS Acknowledgment is made to the following organizations for the use of their libraries in the preparation of this bulletin: University of California, Stanford University, California State Mining Bureau, Union Oil Co. of California, Standard Oil Co. of California, and the Mechanics Mercantile Library of San Francisco; acknowledgment for their assistance is also made to H. H. Hill, C. P. Bowie, A. L. Foster, M. J. Gavin, H. C. Miller, E. B. Swanson, and Miss Louise Janssen, all of the Bureau of Mines, and to Miss Elizabeth H. Burroughs of the Union Oil Co. of California.

Jan 1, 1929

By Rory Cameron, Chuck Edwards

"Stringent environmental performance criteria and regulations, and the desire to minimize water use have made membrane-based treatment and separation processes an attractive option. This has lead to many advances in all aspects of the technology. Membrane separation processes have found application in sea water desalination, brackish water treatment, decontamination of ground water, and wastewater treatment. Development of membranes with better resistance to harsh feed conditions has created new opportunities for the broader application of membrane separation technologies to mineral processing streams. There are examples in mineral processing operations, including treatment of acidic drainage, pre-concentration of pregnant leaching solution in heap leaching operations, separation of acids and metals from waste streams and intermediate process streams, as well as gold and cyanide recovery from a heap leaching operation. This paper provides a brief overview of membrane technology principles, followed by a discussion of current membrane technology applications relevant to the mining and mineral processing industry. The paper further explores the potential for the application of membrane separation as an integrated component in mineral processing operations.INTRODUCTION Increased regulatory pressures, emphasis on water conservation, and scarcity of water in arid regions have resulted in substantial changes in industrial practices in recent years. As a result, many industries have become more open to adopting innovative technologies such as membrane separation. The mining industry, which is typically very conservative, has adopted membrane separation as an effective end-of-pipe solution for effluent and acidic drainage (AD) treatment; however, its use as an integrated component in plant operations has progressed more slowly. With increasingly stringent environmental regulations coupled with the desire for low- and zero-discharge operations, the use of membrane separation technology for achieving acceptable environmental performance may be unavoidable in the future. The relatively small footprint requirement, versatility, and modular construction of membrane separation units facilitate their introduction into existing processes with a suitable feed stream. Membrane separation is not a stand-alone process that provides the ultimate solution to water and wastewater treatment; however, it can often be economically added to conventional waste treatment plants to increase throughput and/or decrease contaminant output (Mortazavi, 2008). Although membrane separation technology has become an established separation technique that is widely used in drinking water production and other industries, it is still considered an emerging technology within the mining and mineral processing industry. This technology offers many potential benefits such as clean water recovery from wastewater, significant reduction of volume requiring conventional treatment, decreased usage of reagents, and acid recovery, all of which lead to increased treatment efficiencies and lower reagent consumption. This could translate to smaller and more efficient plants with lower capital and operating costs and lower environmental impacts. Plant expansion may be facilitated by incorporating a membrane separation unit operation in order to utilize existing treatment systems at higher throughputs."

Jan 1, 2012

[This is the sixth in a series of reports on properties of commercial motor fuels, made in accordance with a cooperative Agreement between the Cooperative Fuel Research (C.F.R.) Committee and the Bureau of tines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935.-36.3/ The present report cover brands of gasoline represented by 1,490 samples plus thus: from the Pacific Coat, which ;sere averaged by the Pacific Coast Technical Group before being submitted and are published exactly as they were submitted. In some areas reports were received from 8 to 10 companies on the same brands of gasoline, Whereas in other areas only one Company reported on a brand. Thus, it can be seen that soma of the data are more representative than others. The inclusion of data from several cities within some of the districts has improved the report by reducing the number of brands reported by only one company. Severe changes have been made in the districts. A new district, Memphis, Tenn., has been formed to include Arkansas any western Tennessee. The Rocky Mountain area, have been divided into three sections. Salt Lake City and Denver form the Middle Rocky Mountain district; Laramie, Wyo., Idaho, Montana, and. Spokane, Wash., are included in the North Rocky Mountain district, and Arizona, New Mexico , and El Paso, Tex., have been combined to represent the South Rock Mountain district. The Cleveland district has been expanded to include Ohio ant. Indiana. Eastern Pennsylvania, Maryland, and northern Virginia are included in the Washington (D. C.) district. The Atlanta district includes Georgia, South Carolina; Mississippee, and northern Florida.]

Jan 1, 1938

A new lead refinery with a capacity of 230,000 tons per year commenced operation at Port Pirie in October, 1959. This plant superseded the refinery which had operated from 1933 with the advent of the continuous lead refining process. The incorporation of new equipment following local metallurgical developments, together with the overseas demand for lead of extremely low antimony content createddifficulties in operating the original plant. The new refinery project was undertaken to cover this disability and to gain the full advantage of the new processes.Desilverising and softening are carried out in units identical in size to those used previously. Metallic zinc is recovered from the entire output of desilverised bullion by vacuum distillation. Final refining is carried out by batch treatment with caustic soda yielding lead of purity previously unattainable at Port Pirie.These two processes replace continuous dezincing by oxidation, a high temperature process which caused large quantities of lead and antimony to be recirculated. The final stage is a batch process; therefore the product composition can be checked before casting. Individual batches can be adjusted to produce special alloys to consumer's specification.Improved casting equipment allows the quantity production of pigs of good physical characteristics either as 56 lb bars or 2000 lb pigs.This, together with the high purity of the lead, assures the Broken Hill Associated Smelters Pty. Ltd. (RH.A.S.) position in world markets.Automatic control systems are extensively employed, particularly on the vacuum dezincing unit.The anticipated financial benefits have been achieved mainly by a reduction in the tonnage of recirculated materials, a smaller labour force, and reduced maintenance requirements.INTRODUCTIONIn December 1956 a decision was made to build at Port Pirie a lead refinery on a completely new site, and in October 1959 the new refinery was brought into operation. This plant superseded the lead section of the old refinery which...

Jan 1, 1963

Jan 1, 1884

By Harpal Parmar

This paper evaluates dynamic methods of pile capacity prediction by comparing their results to static load test results. Dynamic and static pile load test data were assembled from four southeastern states of the U.S. End-of-drive and restrike capacities were evaluated using the Pile Driving Analyzer (PDA) and by wave equation (WEAP) analyses. These were compared to static (Davisson criterion) loads. The best comparison was obtained for restrike PDA results; restrike wave equation analyses values also compared well. The end-of-drive results for both methods-showed relatively poor comparisons. The PDA was recognized as an important tool to measure energy transferred to the pile; this transferred energy was recognized as an uncertainty when conducting wave equation analyses. A statistical analysis showed restrike capacity results to be associated with higher precision and accuracy as compared to end-of-drive methods. The authors believe that restrike dynamic testing is essential to establish long term static soil strength and that it will lead to accurate and cost-effective design of piles.

Jan 1, 1996

By Seth L. Pearlman

Pin Piles are small diameter high capacity drilled and grouted piles also called minipiles or micropiles. They are ideal for building foundations on sites with poor ground conditions, sensitive surroundings, restricted vertical clearance, or difficult access. They are also well suited to foundation underpinning, arresting ground movements, and increasing the capacity of existing foundations. The major factors for selection of Pin Piles are reviewed; drilling, grouting, and design fundamentals are summarized; and a major case history is presented for the underpinning of the 43 story elevator core at the recently opened Mandalay Bay Resort and Casino in Las Vegas, NV.

Jan 1, 2000

By W R. Honeywell

Two series of laboratory flotation tests were carried out to study the treatment of Faraday ore by two-stage flotation. First the acid-consumers and then the uranium minerals were floated. On ore ground in the Faraday mill grinding circuit, and using Faraday mill water in the flotation step, a recovery in the flotation concentrate of from 91 to 93 percent of the uranium was obtained in 45 to 50 per cent of the weight at a grade of 0.24 per cent U30s. The saving of acid in leaching the uranium-bearing flotation concentrate, as compared to leaching the whole ore, ranged from 30 to 46 per cent. The average over-all extraction resulting from flotation and leaching of the flotation concentrate was 88.1 per cent. The best collector for the acid-consumers was sodium oleate. Acintol F A-1 emulsion was the best collector for the uranium minerals, and, in the uranium flotation step, an acid pH in the slurry was found to be necessary. The reagent costs were estimated to be 22 to 26 cents per ton of ore.

Jan 1, 1963

Development of aggregate resources for use in structural concrete has been encouraged in Japan to support infrastructure improvement and national land conservation. Natural aggregate is a valuable resource necessary for sound economic development, and its importance is growing. After completion of aggregate mining projects, planting and afforestation are implemented. But sandy soil in excavation sites is not optimum for the growth of vegetation, and many years are needed before forests are restored. Planting techniques should be improved to support efficient reforestation in a shorter period of time. For this purpose, problems hampering growth of vegetation must to be solved through application of physical and physicochemical techniques to ensure that the environment and the ecosystem will be conserved in project sites.

Dec 6, 2010