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By G. V. Sullivan, B. E. Davis, T. O. Liewellyn

A technique was devised by the US Bureau of Mines to recover coarse [+1.2-mm (14- mesh)] North Carolina phosphate now discarded as waste. Concentration utilizes the difference in particle sphericity between the relatively flat calcite and the rounded phosphate pebbles. Sizing, treatment in a continuous hydraulic classification system, and grinding upgraded a 17% P,O5 reject to 4.5% P,05 with a phosphate recovery of 63%. The CaO: P2O5 ratio was reduced from 2.49 to 1.66.

Jan 1, 1987

By J. R. Caylor

The Mine Safety and Health Administration (MSHA) advanced several initiatives last year to further protect miners' health. Regulatory efforts included the implementation of a Hazard Communication rule for all mines, work on the Single Sample rule for all coal mines, and the Plan Verification rule for underground coalmines. Development and application of new technologies are actively encouraged in preventing miners' hearing loss and respirable dust overexposures. MSHA's successful x-ray program for screening of black lung among coal miners completed its third year. Compliance Assistance efforts are focused on Best Practices, outreach, and technical support for operators' specific challenges.

Jan 1, 2003

By Brian H. Kaye

Efficient design of grinding circuits for efficient production of ultrafine material requires rapid feedback of information concerning the fineness of material leaving the grinding device Generating this information requires efficient sampling and adequate rapid characterization of the material leaving the grinding machinery Recent developments in electrooptic inspection of dry and wet material leaving a grinding device are critically reviewed New methods for characterizing ultrafines are discussed A rapid operating automated cybernetic (intelligent) permeability device for automatic control of grinding circuits using Blaine Index and other fineness indices is described

Jan 1, 1983

By A. V. Glembotsky, N. A. Greshnova, V. P. Seregin, V. A. Glinkin

Based on a new alternative depressant of zinc sulphide - dimethyldithiocarbamate- modern technology has been developed for the treatment of complex polymetallic ores. In addition to its general function (depression of sphalerite and iron sulphides to some extent), this double-acting reagent is a promoter for galena and silver minerals. Laboratory and plant tests, as well as industrial experience have all shown consistently higher silver recovery to the lead concentrate as compared with sodium cyanide, resulting in less pollution and a safer environment

Jan 1, 1995

By Barbara H. Carroll

In order to rapidly evaluate an area for its mineral potential, a reconnaissance exploration program generally includes the following: 1. Outlining an area of interest 2. Identifying known mineral deposits 3. Bibliographic search of the literature 4. Evaluation of geochemical and geophysical surveys 5. Compilation and review of geologic maps The information now available from various government agencies regarding the mineral deposits, geology, and geochemistry may be integrated and used as a tool to rapidly evaluate an area before the field season. The databases most commonly used in the United States are the USBM MAS/HILS system and the USGS MRDS system for their information on mineral deposits; GEOREF and GEOARCHIVE for bibliographic information; and NURE data for the geochemistry and geophysics. In conjunction with the project geologist, this information may be used to plot known deposits and their geochemical signature as well as any other areas of like signature for further examination.

Jan 1, 1985

By S. C. Suboleski

Forecasts indicate that the acid rain bill currently before Congress is likely to cause an increase in demand of 30 to 40 million tons per year of compliance quality coal from Central Appalachia. This represents a doubling of this segment of the coal business. This paper will examine how this doubling can be met, what the likely implications for pricing are, the major uncertainties associated with these predictions, and the likely outcomes of the growth in compliance coal. Finally, some implications for fuel planners will be discussed.

Jan 1, 1993

By P. Riveros, J. Binvignat, V. M. McNamara, D. Koren

The feasibility of recovering cyanide and copper from a gold mill barren solution was evaluated in a small A VR pilot plant. The campaign lasted 64 hours, during which time about 4,000 L of gold mill barren solution were processed. The results showed that A VR is an effective technology for recovering cyanide and copper from barren solutions. Under the best conditions, the copper precipitation and the cyanide volatilization attained 94% and 98%, respectively. Using 5 MNaOH as the absorbent, practically all the HCN gas was recovered in the form of a concentrated NaCN solution containing 70 g/L free CN. Basic engineering design parameters applicable to a large-scale operation were obtained, including the Henry's Law constant and the mass transfer coefficient for HCN gas.

Jan 1, 1997

Design models for belt conveyors used in mines predict both the belt power requirements and belt tensions. Conveyors with slightly downhill profiles are more complex to predict due to the way that models such as CEMA interpret friction. Performance of a particular conveyor in relation to other conveyors in the same system requires an analysis of natural stopping times, braked times and take-up location. A review of CEMA-based PC models is presented for design of underground multi-flight belt systems.

Jan 1, 1995

By Jacob D. Baker

Sulphur dioxide is a versatile gas which has many uses throughout Pulp & Paper, Chemical, specialty Chemical, Mining and other industries. During recent years, S0 2 consumption and distribution patterns have resulted in renewed interests for liquid S0 2 and on site gaseous S02 manufacturing facilities. one relatively new use for S0 2 in the Mining Industry is its use for cyanide detoxification. Our purpose in this paper is to describe the process steps, economics and general technical features of so 2 gas generation using a Jet Type sulphur Burning System.

Jan 1, 1991

By B. Towson, R. F. Dalton, G. W. Seward

This paper reviews the successful application of oxime reagents for the solvent extraction of copper and considers the role that well focussed research initiatives can play in bringing further radical change to the metallurgical industry. Particular reference is made to the Cuprex Metal Extraction Process (CMEP), for the treatment of low grade or difficult to treat sulfide concentrates, using the reagent Acorga CLX- 50 to recover the copper and the reagent Acorga ZNX-50 for the recovery of zinc from chloride solutions. Other new extractants, currently in development, are also referenced.

Jan 1, 1994

By U. Paschedag

Today's modern longwalls have to produce high outputs with maximum availability and running time with the additional requirement of ever increasing panel width and length high-performance face conveyors require intelligent solutions for the integration of drive systems and chain tensioning devices into the overall longwall automation. The fully automated chain tensioning system allows the operation of an AFC with optimum chain tension at all times regardless of actual load on the conveyor. For the heavy-load start-up, the accurate load-sharing and an efficient overload protection of modern AFC's WESTFALIA and Dodge jointly developed the integrated WB/CST drive system.

Jan 1, 1995

By R. J. Miller

Mechanized Roof Supports (MRS) have dramatically improved safety and productivity of retreat pillar mining in coal. Due to low capital cost and greater flexibility, retreat panels have in some cases approached the productivity of a longwall. Because of improved safety and rapid set-up time when compared to conventional timbering, MRS are driving a return to retreat pillar mining in many situations. This paper describes how panel layout can be optimized for safety and operational efficiency when using MRS for retreat pillar mining of coal. The potential for significant unit cost reductions will also be addressed.

Jan 1, 1996

By A. B. Mayer

A generic task summary for design and implementation of hydrogeology programs at open-pit mine operations is presented as a guideline for management. Rigorous assessment of the local and regional hydrogeologic system is necessary to plan dewatering activities and to address environmental concerns. Dewatering activities include calculation of dewatering requirements, design of dewatering systems and evaluation of dewatering-water disposal areas. Environmental concerns include calculation of dewatering and water-disposal impacts, mitigation of soil and ground-water contamination and acquisition of water rights. Three-dimensional numerical models are commonly used to support these analyses. A thoroughly developed hydrogeology program provides an interactive basis for dewatering feasibility decisions and for support of environmental permits and regulatory compliance.

Jan 1, 1993

By A. S. Paschoa, A. W. Nóbrega

INTRODUCTION There are now over twenty years since the radiological characteristics of the brazilian regions of Araxá, Tapira and Barreiros, three locations adjacent to each other, in the state of Minas Gerais, Brazil, started being surveyed by investigators from the Instituto de Biofísica da Universidade Federal do Rio de Janeiro (IB/UFRJ), Pontifícia Universidade Católica do Rio de Janeiro (PUC/RJ), and New York University (NYU) (Roser and Cullen, 1958; Cullen et al, 1980). The importance of the Araxá apatite – Ca5,(P04)3(OH, F, Cl) - and pyrochlore - NaCaNB206F - for the production of large quantities of fertilizers and niobium was early recognized (Roser and Cullen, 1958). Interesting data have been gathered and published throughout the years on the contents of naturally occurring radionuclides in geologic materials, soils, grass, foods and waters of the Araxá region (Eisenbud, et al., 1964; Penna Franca, et al., 1965a, b; Roser et al., 1966; Penna Franca et al., 1970; Cullen, 1977; Penna Franca, 1977; Cullen and Paschoa, 1978; and Cullen et al., 1980). The radioactivity of the Araxá region is associated with mineral deposits of niobium rich pyrochlore and phosphate rich apatite. There are in this region mineral ores with 3 to 5% pyrochlore with 2 to 2.5% Th as Th02 and 50 to 150 ppm U308 in the matrix, while the apatite deposits contain up to 150 ppm U308 and a thorium concentration similar to that of the pyrochlore deposits (Paschoa and Palacios, 1981). As an indication of the high thorium content of the Araxá soils the 228Ra and 224Ra activity concentrations were reported to range from 10.6±0.2 to 62.4±0.7 pCi228Ra/g soil in 7 samples and 2.1±0.1 to 104±1 pCi224Ra/g soil in 19 samples (Cullen, et al., 1966). The uptake of radium isotopes by edible roots vegatables and fruits growing in the soils of the Araxá region can be illustrated by the data listed in Table I. The biological availability of natural radium isotopes in some segments of the Araxá soil allows a large variation in the 228Ra, 224Ra and 226Ra concentrations in vegetables and edible roots, as can be seen in Table I. This fact makes quite difficult a quantitative local assessment of the radiological implications of mining the Araxá mineral deposits of pyrochlore and apatite for production of niobium and phosphate fertilizers, respectively; since one cannot easily separate the naturally occurring from the technogically enhanced radionuclide contents of foods. The position of the city of Araxá inside the contour of the state of Minas Gerais appears in the upper part of Figure 1, which shows the outlined map of Brazil with the positions of the cities Brasilia and Rio de Janeiro also indicated. The lower part of Figure 1 is a representation of the Araxá region in an expanded scale, which indicates the locations of the pyrochlore and apatite deposits in relation to the city of Araxá, as well as the nearby hydrographic basins. The distance between the city of Araxá and the pyrochlore deposit is about 8 km, and between the pyrochlore and apatite deposits is 4 km. This paper deals tentatively with the radiological implications of the industrial operations taking place in the Araxá region for the exploration of the pyrochlore and apatite deposits. However, one must bear in mind, firstly, that the radiological implications of these industrial activities are by far too complex to be covered adequately by the limited amount of data to be presented in this paper, and secondly, that such implications cannot be considered of local character only. INDUSTRIAL OPERATIONS The commercial exploration of the Araxá deposits of pyrochlore and apatite started only few years ago, motivated by the increasing demand of niobium and phosphate fertilizers in Brazil and the world. As a consequence of the industrial operations in Araxá, a redistribution of the uranium, thorium, and radium originally present in the local deposits of pyrochlore and apatite started occurring in the seventies, with possible radiological implications for the Araxá region and its immediate surroundings, not to mention the destinations of the end products of such industrial operations. A literature review on the radioactivity associated with the extration industries of selected minerals was made by the USEPA (Bliss, 1978). The low level radioactive wastes of the industries for copper ore mining and rare metals processing have been object of particular attention (Fitzgerald, Jr., 1976; Eng, et al., 1979), but the short and long term implications of the radioactivity associated with the niobium industry were also subjects of concern (Knight and Makepeace, 1978). Recently, high 232Th and 226Ra concentrations in samples from the tin mining industry in West Malaysia were reported (Hu et al., 1981). A great deal of attention has been dedicated to the implications of the redistribution of radionuclides originally present in the mineral ores used by the phosphate fertilizer industry (Moore, 1967; Menzel, 1968; Spalding and Sackett, 1972; Eisenbud, 1973; Guimond and Windham, 1975; Guimond, 1976; Roessler,

Jan 1, 1981

By Tamás Megyeri, Dániel Borbély, Vera Szánto, László Kovács

"Upon completion, the Bátaapáti deep underground radioactive waste repository complex (National Radioactive Waste Repository - NRWR) will provide safe final disposal for low and medium-level radioactive waste from the Paks Nuclear Power Plant in Hungary. The waste emplacement is in progress and one of the main concerns related to the development is ensuring a feasible plan is in place for permanent repository closure. Detailed hydrogeological observations and safety assessments revealed that the clay filled fault zones penetrated with the access tunnels play determinant role in the long-term confinement performance of NRWR, so they need to be plugged. Detailed mechanical analysis and numerical modelling of the tunnel constructed through a fault zone is presented here to gain a better understanding of the rock mass and rock support behavior. The effect of stress reflection is demonstrated and its consequences are described in detail. A recommendation is given for tunnel support design in such conditions. INTRODUCTION Crossing fault zones is a challenging task during tunnel construction and can lead to failure if not properly accounted for during design and construction. These failures are can be caused by high water inflow or stability loss of the rock mass surrounding of the tunnel (examples can be found in CEDD, 2015). The prediction of the magnitude and development of displacement has a considerable impact on issues during tunnel construction. Changes of rock mass stiffness or structure ahead of the face, to a great extent influencing stresses in the vicinity of the tunnel and thus deformations (Steindorfer, 1998). Further research with numerical simulations was carried out, and the qualitative and quantitative evaluation of displacement vector is presented in (Grossauer et al, 2005). The concern associated with crossing fault zones was considered during the design of the Bátaapáti deep underground radioactive waste repository complex (NRWR) in Hungary. In the case of NRWR project, the fault zones have an impact on maintaining the stability of the surrounding rock mass as well as the final sealing of the repository. As part of the final closure design, a complex numerical modelling program was completed to gain a better understanding of the mechanical behavior of the rock mass and the monitoring observations during construction. Even though the need for the presented study is closely related to the NRWR project, the results can be used in any project related to fault zone crossing. The methodology used to better understand the impact of crossing fault zones for the NRWR project is presented in this paper. First the project background is introduced including an overview of the underground facilities, the aim of the repository, and the construction experience gained from the first crossings of the fault zones. After that the in-situ and laboratory testing is summarized. The numerical modelling methodology is detailed in the next section. Not only the outcome of the model is presented, but the results are compared with the experience and observations made on site. Since a good agreement is found between the actual and the modelled behavior, the conclusions are based on the validated result. To fulfill the aim of the paper, the stress reflection concept is introduced to explain the mechanical behavior of the fault zone and the rock support; furthermore straightforward suggestions are made for rock support design."

Jan 1, 2016

By Carl C. Martin

The treatment of ores in preparation for fatty acid flotation is characterized by a wide divergence in methods, and attempts to define "common practice", even for the same type of mineral, are usually of little value because of the numerous exceptions. Such factors as desliming, pulp density, pulp temperatures, and reagents for conditioning are successfully employed under conditions representing almost extreme opposites. More precise control of variables is necessary than with sulphydric flotation processes It appears likely that variations result from independent development of a process from the multitude of variables that characterize fatty acid flotation and the ores of non-metallic minerals. Consequently, a symposium is a suitable way of presenting a summary of pretreatment methods for fatty acid flotation processes, together with froth control practices, as they exist today.

Jan 1, 1959

By Donn W. Leva

In North America, pipelines move more material than any other form of transportation. 1 Pipelines have been used principally for the transportation of liquids and gases; however, slurry pipelines have made notable gains in recent years enabling solid materials to be moved efficiently by pipelines. The obvious advantages of pipe-lines --low maintenance, low operating costs, minimal impact on the environment, greater land use, low labor intensity, safety and high operating factor --have stimulated researchers in England, West Germany, Japan, USSR and the USA during the past ten years to develop pneumatic capsule pipelines for the movement of bulk materials in large quantities. As a result of this work, pneumatic capsule pipelines are now available for the movement of dense bulk materials. Through these pneumatic capsule pipelines, material is moved in wheeled capsules which are pushed through the pipeline by flowing air. In this paper, a capsule pipeline system developed by the Georgia Institute of Technology and Tubexpress Systems, Inc. of Houston, Texas is discussed. The Tubexpress System Major Components The pipe used for a Tubexpress capsule system is standard thin wall welded steel pipe. Since pressures in the system generally do not exceed one atmosphere, the controlling design criteria for wall thickness of the pipeline is pressure from the overburden of the backfill if the line is buried or the structural requirements for supporting itself and the load if it is suspended or supported on piers. The air pumping system for Tubexpress is a combination of

Jan 1, 1977

By T. McCallum, B. Wellbrook, T. Ratnaweera

"Pressure oxidation (POX) leaching of copper (Cu) concentrates continues to be explored as the next generation of leaching processes to sustain existing Cu Solvent Extraction/Electrowinning (SX/EW) operations as easily leachable ores become scarcer. The leach liquors produced, particularly from total pressure oxidation, contain elevated concentrations of Cu and acid, making solvent extraction processing more challenging. Addressing this challenge will require innovative processing techniques and continuous improvement to be successful in achieving satisfactory physical and metallurgical performance in the SX plant. The ability to efficiently process these feeds via SX plays an important role in the continued success of POX technology. Characteristics of a concentrate leach pregnant leach solution (PLS) are discussed, along with best practices that should be considered for processing by SX. Findings discussed in this paper will shed light on ways to reduce process risk and bring additional improvement to the industry with minimal change to the SX plant. INTRODUCTION Hydrometallurgical processing of copper concentrates continues to gain interest from the industry. Treatment by smelting and electro refining continues to dominate, accounting for ~80% of global copper production, but is faced with its own challenges. The case for increased hydrometallurgical processing has been discussed as high grade ore deposits are diminishing, capital costs for smelting are high, and the environmental aspects present challenges for sustainable practice. The hydromet copper industry is also turning a corner as easily leachable copper oxide deposits are depleting, and excess SX-EW capacity exists in certain regions. The transition to hydrometallurgical processing of copper concentrates will take a bit of effort as leaching of copper sulfides is difficult and byproduct credits must be considered. Various POX leaching processes have been studied and proposed to the industry as viable practices. Of the many processes, commercial use has been practiced with the Mount Gordon Copper Process, total and partial pressure oxidation by Freeport-McMoRan at their Bagdad and Morenci, Arizona complexes, the Sepon Copper Process in Laos, and the bioleach BIOCOP™ process in Chile. The experience related to the current paper centers around Cu concentrate leaching performed by Freeport McMoRan (known as CLP). The patented process was developed as an alternative to smelting and refining in 1998. The technology applies to both molybdenum and copper concentrates. Commercial CLP research and development began with Phelps Dodge in 1999 to 2001. The first commercial plant was commissioned in 2003 at the Bagdad operation. Initial operating conditions of the Bagdad CLP were under high temperature conditions before converting in 2005 to medium temperature conditions. In 2007-2009, the CLP technology was commissioned in Morenci, operating medium temperature and high temperature lite conditions until shutting down due to the economic downturn. The Morenci CLP restarted operation in April 2015 due to acid production benefits for the Morenci leach operations. Renewed solvent extraction test work initiated well before restart and has been an ongoing focus for further SX plant optimization."

Jan 1, 2018

By C. P. Miller

In a study of the usefulness of geochemical and biogeochemical prospecting for nickel made about two years ago, approximately ten localities, representing several different types of nickel occurrences were sample, and about 1500 samples of plant and soil were collected. This report will briefly cover the data and results for two areas, and s summary of guides for prospecting.

Jan 1, 1959

By d&apos, J. A. Oliveira, A. K. L. Resende, L. F. G. Assumpção, J. D. Neto

Kaolin samples from Rio Capim Resources were treated in conventional and superconducting magnetic separators to study the main variables that influence the impurity removal process. Two coating clays and a delaminated clay were tested. The variables studied were retention time (cross-sectional velocity), magnetic-field intensity and matrix type. The feed brightness ranged, from 84.7% to 87.6% ISO, for the coating clays and ranged from 80.7% to 85.4% ISO for the delaminated clay. Using a conventional magnetic separator with an applied, field of 1.5 to 2.0 T (tesla), the brightness values were higher than 88% ISO for the unleached coating claw products and were higher than 87% ISO for the unleached delaminated product. With a maximum field intensity in the superconducting machine of 5.0T unleached brightness values higher than 88.5 % ISO were attained for both coating and delaminated clays.

Jan 1, 1997