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By D. Butler

Subsurface density changes can be detected by very precise surface gravity measurements. A feasibility study, combined with field experience using modern instruments, will indicate the probability of success. In addition to projected anomaly parameters, surface conditions that effect the survey precision must be evaluated. Examples with excavated zones at 9 m (30 ft) of depth and [+] 22 microgal error are compared to the same model at 30 m (98 ft) of depth. The figures illustrate anomaly detectability. The survey error is a function of surface topography and lateral density variation in the very near surface.

Jan 1, 1990

By A. Cecala, J. Noll, J. Hummer

"NIOSH has observed that many control rooms and operator compartments in the US mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room which had no cleaning system for intake air, a filtration/pressurization system originally designed for enclosed cabs was modified and installed. Eighty-seven percent of submicron particles were reduced by the system at static conditions, meaning that greater than eighty-seven percent of respirable dust particles should be reduced. The particle size distribution for respirable dust particles are greater than for submicron particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced which is an important component for an effective system and minimizes particles (e.g. dust) from entering into the room. The intake airflow was around 118 cfm, which is greater than the airflow suggested by ASHRAE for acceptable indoor air quality. INTRODUCTION Chronic overexposure to respirable silica dust (particle diameter < 10 microns) leads to a progressive lung disease known as silicosis. Workers who develop silicosis have an increased incidence of lung cancer and pulmonary disorders. In June 1997, the International Agency for Research on Cancer (1) found sufficient evidence to declare that inhaled crystalline silica in the form of quartz and cristobalite is carcinogenic. Mining is one of the leading industries for occupational exposure to silica dust (2-7). Control rooms located in dusty areas in some mines are of particular concern (8). Many mineral processing operations utilize operator’s compartments and/or control rooms to house workers who are performing particular job functions. Most industrial processing mills have rooms where a worker looks out over the facility and has direct control over the product flow throughout the entire building. In addition, primary crusher operators are often located in a compartment from which they are able to view the primary crushing function. Their job is to control when trucks dump into the primary jaw crusher and the rate of feed of the ore from the hopper into the crusher. Many of these control rooms and operator booths do not have filtration systems capable of cleaning air entering the control room or booth, which can result in elevated concentrations of dust in the room or booth. To reduce the dust concentrations in these rooms, it would make sense to clean the entering air with filtration/pressurization units similar to those proven to provide a clean environment in enclosed cabs."

Jan 1, 2016

By John Wiebmer

Several industry trends are putting new demands on surface mining equipment. This is true both on the “hard” side of the equipment business - the research and product development programs, and on the “soft” side - the business processes, human resources and competitive strategies. This article describes seven key industry trends and the impact each is having on surface mining equipment suppliers. 1. Globalization Earth-spanning technologies are shrinking the world into an economic village, causing corporations to think and plan on a global scale. This “globalization” is one of the great buzzwords of the 1990s, meaning precisely whatever the user says it means. In this case, let us take it to mean that political boundaries arc less restrictive than in the past, permitting mining companies new freedom to roam the globe for ore bodies. Evolving out of this are global mining houses that have ownership and management interests in labyrinthian webs of mines spanning the world. There are several impacts on surface mining equipment suppliers.

Jan 1, 1994

By J. C. Agarwal

Major scientific discoveries cannot be programmed. New or frontier technology, however, can and should be planned. It is the vital force underlying the business strategy of a vigorous and profitable mining and metals company. Generally, a radical departure from existing technology is required to 1) Enhance the competitive value of ore reserves, i.e., to turn low grade or marginal reserves into competitive reserves. 2) To increase yield and decrease costs. 3) To decrease investment. 4) To increase mine life. 5) To improve product quality to meet market demands. The very definition of frontier technology implies that it is so different that the old plant, if already in use, will not be directly suitable to use the new technology. Therefore, a priori, we know that the commercialization of frontier technology would very likely involve new investment. The recommended technique of economic and technical analyses, I propose to call "Success Analysis.&apos;&apos; Simply stated, it forces us, by step- by-step procedure, to ask "what is needed to succeed in this particular project." Therefore, the first step is to identify what is meant by "success." The definition of "success" requires an agreement with top management or sponsors of the project as to what constitutes "success" in their minds as contrast to the technical people perception of "success." In general, top management would define success as meeting: 1) The technical objectives, i.e., technology being developed would produce the desired product at the acceptable quality. 2) Financial objectives, i.e., when commercialized, the project&apos;s capital cost, operating costs and return on investment are better than the projects they would normally fund. The return has to be better because new technology is inherently riskier. 3) Marketing objectives in that the project will produce product of acceptable quality in timely manner, i.e., scale-up to commercial plant would not cause undue delays in start-up and that large fix-up expenditure would not be required to protect the projected return on the investment. Many projects are started in the laboratory to develop "Frontier Technology" in mineral processing. Most of these efforts are never commercialized. There are many causes of these failures. The major causes are listed below: 1) Inadequate communication with the sponsors of the project so that project objectives are defined and agreed to by all. 2) Ill-defined technical problems. 3) Incomplete development of technology. This has two major components: a. Incorrect scale-up and engineering. b. Inadequate start-up and maintenance planning. 4) Incomplete and over-optimistic process economics. 5) Lack of understanding of the future behavior of the marketplace. 6) Failure to complete R&D effort by the time it is needed. 7) Incorrect projections of human resources required; that is, technical, managerial and operating. 8) Lack of realistic forecast of the expenditures required for commercialization of the R&D effort. These pitfalls can be avoided by comprehensive planning and the use of success analysis technique. The major elements in "Success Analysis" are: 1) Identification of the "need" for new technology. 2) Unbiased and complete scale-up engineering. 3) Acceptable economic feasibility with enough margin of error in the sale prices and operating costs to justify the inherent risks in frontier technology. 4) Timing for availability of investment capital and markets. Many failures in the development of frontier technology are preordained because the initial selection of the research project has been without adequate attention to the needs of the industry. Many very innovative hydrometallurgical processes for recovery of copper from concentrates were developed in the past twenty years. They have not adapted except to a very minor extent because they did not satisfy the success analysis criteria. The copper industry in North America needed a process to compete against high grade ores and to avoid

Jan 1, 1985

By E. G. Joe

Introduction Uranium mining has been actively carried on in Canada for over twenty-five years mainly in Ontario at Elliot Lake in Bancroft, and in Northern Saskatchewan at the operations of Eldorado Nuclear Ltd. During this period, approximately one hundred million tons of mill tailings have been created and lie mainly on the surface close to the mining and milling installations. If all of the present reserves of uranium ores in Canada are mined, a further eight hundred million tons of mine tailings could be created in Ontario, Saskatchewan, the Northwest Territories, Labrador and British Columbia. The present control of effluents from existing tailings is managed by the operating mines under the regulations of both federal and provincial control agencies. It is the long-term effect of these tailings on the environment that has not been clearly defined or measured. Several years ago, the Canada Centre for Mineral and Energy Technology of the Department of Energy, Mines and Resources, embarked upon a program of research directed at the long-term effects of uranium mine tailings. Much of the research to date has been on tailings in the Elliot Lake, Ontario area where some tailings piles have existed for over twenty years. The program consists of two projects, one to address the problem of existing tailings and the other to examine alternatives in the management of current and future tailings. TAILINGS CHARACTERISTICS Uranium tailings are generally the result of sulphuric acid leaching in which the uranium and alkaline minerals such as carbonates and chlorites are leached out. If the ore contains sulphides, these minerals potentially present an additional hazard of acid generation over time and could increase the mobility of heavy metals and some radionuclides such as thorium-230. Except for the extracted uranium, most of the radionuclides from the ore remain in the tailings pile. Uranium ores in Canada span a wide variety of mineralization and associated gangue composition. Uranium minerals include pitchblende, uraninite, uranothorite, brannerite and the phosphate uranium minerals autunite and saleeite. Gangue minerals vary from acid consuming carbonates, and chlorites to acid producing sulphides and inert silicates. With such a wide variety in ore composition, the characteristics of the resultant tailings in Canada are in many cases site specific and the solutions to the long-term effects of these tailings may also be site specific.

Jan 1, 1980

By D. D. Misra

Though computer simulation of coal beneficiation has been in use for nearly two decades the models used in the programs for the simulation of the crushing processes concentrate mainly on the size distribution. This paper suggests the use of an empirical equation approximating to the cumulative probability or error function for the simulation of the liberation process in coal crushing. The algorithm outlined here can be incorporated in a computer program already having a size distribution model.

Jan 1, 1989

By D. W. H. Su

"This paper presents the results of a comprehensive study conducted by CONSOL Energy, Marcellus Shale Coalition, and Pennsylvania Coal Association to evaluate the effects of longwall-induced subsurface deformations on the mechanical integrity of shale gas wells drilled over a longwall abutment pillar. The primary objective is to demonstrate that a properly constructed gas well in a standard longwall abutment pillar can maintain mechanical integrity during and after mining operations. A study site was selected over a southwestern Pennsylvania coal mine, which extracts 1,500-ft-wide longwall faces under about 600 feet of cover. Four test wells and four monitoring wells were drilled and installed over a 125-ft by 275-ft centers abutment pillar. In addition to the test wells and monitoring wells, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the 1,500-ft-wide longwall panels on the south and north sides of the abutment pillar were mined by. To evaluate the resulting coal protection casing profile and lateral displacement, three separate 60-arm caliper surveys were conducted. Prior to the longwall panels being mined by, a number of 3D finite element simulations were conducted to estimate subsidence at the surface, coal pillar pressure increases, the resulting coal protection casing profile and displacement, and the vertical and horizontal displacements in the four monitoring wells. Comparisons of the pre-mining 3D finite element simulation results and the surface/subsurface/underground instrumentation results show that the measured test well and IPI casing deformations and profiles are in reasonable agreement with those predicted by the 3D finite element models, and that the measured surface subsidence and pillar pressure are in excellent agreement with those predicted by the 3D models, which serves to validate the 3D finite element models. Parametric studies employing the validated 3D finite element models demonstrate that larger coal protection casing thickness is expected to have little effect on the lateral deformation, although it may reduce the magnitude of casing plastic deformation, and under deeper cover (~1,100 feet), lateral casing deformation is expected to be smaller, although larger plastic casing deformation may be present near the seam level. Also, evaluation of various casing and cementing designs using the validated 3D models clearly indicates that, when all casings are grouted to the surface except the intermediate and production casings, the intermediate and production casings show little deformation and no plastic strain. This research represents a very important step and initiative to utilize the knowledge and science obtained from mining research to improve miner and public safety as well as the safety and health of the oil and gas industries"

Jan 1, 2017

By Robert H. Marshall

The application of simulation to production planning at a large, complex open-pit mining operation proved to be challenging and enlightening. The mine is divided into two separate pits and several dump areas which are served by the same truck fleet. The operating system consisted of shovels of two different sizes, wheel loaders, and a fleet of three different truck types moving material from seven source locations to ten dumping sites. The interconnecting haulroad network included many common segments. There were operating constraints unique to the system, such as: traffic rules; manpower limitations; shovel, material-type, and destination priorities and production limitations; and a unique, non-centralized dispatching method for truck distribution. The truck distribution was further constrained by the matching of trucks to shovels, loaders, and destinations by truck type. The gathering and transformation of input data as well as the evaluation of results and validation of the model were also challenging. Despite a high level of sophistication in production reporting, some input data were neither readily available nor backed by field observation. As a result, many innovative techniques had to be used to develop realistic input data and to validate the simulation results. Nevertheless, this case study definitely proved the feasibility of applying computer simulation techniques to short and long range mine planning and budgeting at a large, complex mining operation.

Jan 1, 1982

By G. E. Karantzavelos

Introduction Pure alunite (KAl3 (SO4 )3 (OH)6 ) contains 37% A1203. In the alunite ore found on Milos Island, Greece, opal is the principal gangue while some aluminum, iron, and titanium oxides are also present. Processing of alunite ore leads to the recovery of potassium sulfate, alusil (alumina-silica mixture), and sulfur dioxide. An interesting process has been developed in Greece (Svoronos, 1977) consisting mainly of roasting the alunite ore mixed with KCl to disrupt the mineral lattice in preparation for separating its components. The thermal decomposition of alunite at approximately 600°C occurs by the reaction: KAl3 (SO4)3 (OH)6 + nSiO2 + 6KC1 - 4 K2SO4 + 3 A1203 . nSiO2 + 6 HCl + 3H20 According to the process pure alunite mixed with 543 kg KCl, 840 kg K2SO4, 370 kg alusil, 264 kg HCl, and 65 kg H2O are produced. The roasted calcine is leached in hot water. The potassium sulfate leach slurry is then thickened and washed to obtain a solid residue (alusil) plus a solution rich in potassium sulfate. Assuming the alunite ore feed consists of 50% to 60% alunite, the solid residue might consist of approximately 22% to 27% A1203, silica, iron, and titanium oxides. This leach residue could be digested in a hot sodium hydroxide solution to dissolve alumina. An amount of the alumina (approximately 10%) would not dissolve. In addition, part of the silica would dissolve requiring removal from the solution in a subsequent desilication operation. The same leach residue could be attacked by mineral acids such as a diluted hydrochloric acid to extract aluminum chloride (Sawyer et al., 1983). Alumina and aluminum are presently produced from bauxite of which Greece has important reserves. If this aluminous material (alusil) could be beneficiated by any physical process, then it would be considered as a raw material for the production of fire-clay refractories instead of an alternate source of alumina. Experimental procedure Extensive laboratory work (mineralogical and chemical analyses) indicates that alusil is a mixture of liberated (mostly) alumina and silica particles, not a natural silicate mineral. Table 1 shows the chemical assays of two alusil samples that were obtained from a roasted alunite ore leaching pilot plant. The samples used for the experiments were a very fine alusil powder (K80 = 400 mesh, 38 µm). These were pulped in tap water. Desliming of the pulp before each flotation test was ineffective. Flotation tests were performed in a 2000 ml Denver cell. A standard 500-g sample was first conditioned at a pulp density 50% solids for 5 min with hydrofluoric (HF) acid solution (40%). The temperature of the conditioned pulp was measured and kept nearly constant at 50°C. The pH of the conditioned pulp was also regulated to 2.5-3 with HF solution. Then ARMAC C solution (2%) as well as two drops of fuel oil and one drop of AEROFROTH 65 were added and the pulp was reconditioned for 2 min. After conditioning, the viscous pulp was transfered to the flotation cell. It was then diluted with warm water to about 15% solids and floated to separate silica from alumina particles. A rougher froth product that was cleaned and recleaned was obtained from the flotation tests.

Jan 1, 1987

By David V. Fitterman, David L. Campbell

We&apos;ve used direct current resistivity (DC), electromagnetic (EM), induced polarization (IP), and ground-penetrating radar (GPR) geoelectrical methods to study mine dumps. The results reflect lithology, pore water saturation, and dissolved solids in the pore water. If the pore water has a pH less than 5, conductivity maps can indicate acid generating potential. IP measurements can help distinguish mineralogy in mine dumps, especially concentrations of sulfide minerals. EM and DC can help locate acidic/high TDS groundwater associated with mine dumps. GPR methods failed at the sites we studied in the West. Our own conclusions are augmented by those from the recent literature.

Jan 1, 2000

By J. J. Scott

Friction Rock Stabilizers, trade name Split Set*, is a new support system invented by the author and under development by Ingersoll-Rand and Lee-Norse Company. Split Sets are a substitute for standard bolts or fully grouted resin bolts and have certain advantages which are: 1. Improved safety for the miner 2. A rational design is possible based on rock mechanics principles 3. Supports can be made either to be yieldable or rigid 4. Supports can be used to build a roof beam or to suspend roof material 5. It is cheaper than the resin system and costs about the same as standard bolts.

Jan 1, 1974

By G. E. Jones, G. K. Hoffman

Two Sun Juan Basin studies were completed through the USGS National Coal Availability program. The study areas are in the northwest Bisti field (Fruitland Formation) and in the eastern Standing Rock field (Menefee Formation). In the Bisti and Standing Rock areas, the original coal resource5 are estimated at 4.66 and 3.1 7 Gt (5.14 and 3.49 billion st), respectively. The Bisti coal resources are greatly reduced by the Bisti-De-Nu- Zin wilderness area, which contains an estimated 1.13 Gt (1.25 billion st) of coal. Technological restrictions remove 32.5% from Standing Rock&apos;s original resource. Available resources are 60%. 2.79 Gt (3.07 billion st), of the Bisti original resource and 65%, 2.07 Gt (2.28 billion st), of the original Standing Rock resource.

Jan 1, 2002

By J. M. Richardson, A. L. Mular

Metallurgical balances are fundamental to the successful design and operation of concentration and dewatering circuits. With computerized balance techniques gaining prominence in recent years, it is essential that engineers understand the basic principles that underlie the new methods, as well as the various applications for design of new plants and analysis of existing operations. This chapter discusses two important types of metallurgical balance: (1) steady-state design (2) operating data adjustment Application of computerized steady- state design balancing is demonstrated through the example of a typical copper concentrator flowsheet. Operating data adjustment to achieve a consistent balance is demonstrated for a typical concentrator operation.

Jan 1, 1986

By J. H. White

It is hypothesized that the Hotelling valuation principle (HVP) can determine the value of developed gold reserves using simple methods and easily obtainable data. This paper reports the results of an empirical test of this hypothesis. The model for the HVP is given by [V R=Cp-0(1) or V - CP-0&apos; R(2)] where p = current spot price of gold per oz, [c] = average extraction cost of gold per oz, V = current market value of the gold in the ground (dollars) and R = gold reserves (oz). Using publicly available data from North American gold companies, we obtained data for V, R, p and c, and we ran a simple linear regression using Eq. (1) as the definition of the dependent and explanatory variables. By examining the value of the coefficients of the resulting regression equation, we can draw conclusions as to whether or not the HVP can be confidently used as an estimator of the value of developed gold reserves.

Jan 1, 1997

By M. J. Virnig, J. M. W. Mackenzie, M. W. Johns

The properties of Henkel's Aurix® resin which uses a guanidine functionality to recover gold by ion exchange have been described in publications of the International Mineral Processing Congress and Randol International (1)(2). The purpose of this paper is to provide an update on the results of further testwork using Aurix®. Specifically, this paper presents the first results of resin in pulp testing, all the results previously reported were for testwork carried out using synthetic gold leach solutions.

Jan 1, 1995

By G. Jim Cardwell

The question "what constituents should be determined?" is one that defies a simple answer, because earth scientist being what you are, the rock and mineral analyst will eventually be called upon to determine about three quarters of the elements in the periodic table. The concentrations of these analyses will range from as low as 1 ppb to 100% of the material being analyzed. The most important thing to remember about a quantitative analytical result is that it can only be an estimate of the concentration of the analyte present. A measure of the reliability of that estimate is given by statistically derived statements of the precision and accuracy of the measurement. When evaluating your data an understanding of precision and accuracy are of paramount importance. Precision is the measure of agreement between replicate values while the accuracy of a determination is the concordance between it and the true value. There is no quarantee, however, that a precise answer is an accurate one. The numerical difference between the two values is the error. When evaluating your data, the repeats analyzed with your samples will identify the precision and control standards of U.S.G.S. or Canadian Certified Materials quality will identify the accuracy. The main problem is this data is routinely withheld from the report, or was it ever included in the analysis of your samples?

Jan 1, 1983

By John L. Stafford

The ROEMMC combustion system was originally conceived as a means of utilizing solid fuels that would otherwise have been wastes requiring disposal and convert these fuels into useful energy sources. This concept follows as an extension of the application of residual waste incineration with energy recovery practiced in the lumber, manufactured board, sugar cane, and other industries. The incineration of these wastes in the furnaces of steam generating equipment is thoroughly described (1, 2, 3, 4, 5, 6, 7). The fundamental principle of the ROEMMC system is temperature control which makes possible the maintenance of the non-combustible fraction of these solid fuels in a dry solid state and their separation from the gaseous products of combustion. This philosophy of ash removal and the "slagging" philosophy are compared. The ROEMMC equipment function and applications are described.

Jan 1, 1978

By E. Suoninen, K. Laajalehto, L. Kartio

Efficient separation of pyrite from other sulfides is of great importance for the metallurgical performance of flotation processes. In this work Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) were used to study the surface chemistry of pyrite in depression, activation and xanthate adsorption under conditions of controlled potential. Modifications of pyrite surfaces after treatment with depressants (lime, sulfur dioxide, sodium cyanide) and after activation with metal ions (Cu, Pb) were studied. The principal adsorption product identified on pyrite was dixanthogen whose formation started at about +0.15 V and +0.25 V (vs, SHE) in ethyl and amyl xanthate solutions, respectively. Copper xanthate was formed on copper(II) activated pyrite. Activation mechanism of pyrite by copper(II) salts is likely to be electrochemical where copper occurs as copper(I) on the surface of pyrite. Effective depression is achieved by sulfur dioxide and sodium cyanide. Depression at high pH is due to formation of iron(III) hydroxides. Calcium ions do not affect the electrochemistry but adsorb on pyrite and reduce the surface sites for dixanthogen adsorption.

Jan 1, 1995

By R. F. Korcak

There exists a wide array of industrial byproducts that produce beneficial responses in the soil/ plant environment. These materials range from clean-coal-technology residues produced during the generation of electric power (particularly those high in gypsum) to mineral fines produced by the aggregates industry (i.e., sand, gravel and crushed stone). A number of these materials are examined in relation to potential nutritional interactions in soils and crops with emphasis on trace elements. The significance of utilizing these materials in agriculture as a component of sustainable agricultural systems are discussed.

Jan 1, 1997

By Tim Neil, O&apos

Introduction Compania de Carbones de Chile (Cocar SA) has brought into production Chile&apos;s first large-scale, open-pit coal mine, located in the Magellan Province. The US $65 million project includes a 1.1-Mt/a (1.2-million stpy) subbituminous steam coal mine and a mechanized bulk loading marine terminal with water depth sufficient to receive 60 kt (66,000 st) Panamax vessels. The loading terminal will be one of the largest in Chile. The Pecket coal project is expected to save Chile about $40 million in energy production costs and a further $100 million in oil imports, or about 25% of the country&apos;s oil import costs. Pecket coal will generate electricity for Codelco and will also supply general electricity needs for northern Chile. The Pecket coalfield is located on the Brunswick Peninsula, about 30 km (19 miles) northeast of Punta Arenas, the provincial capital, as shown in Fig. 1. Pecket is part of a large, coal-bearing basin. It extends from Punta Arenas 250 km (155 miles) north to Puerto Natales and across the border into the Rio Turbio coalfield in Argentina. A fleet of large and small O&K hydraulic shovels and backhoes is used to dig and load overburden and coal into mining trucks while O&K graders maintain the haul roads in and around the pit. Coal occurrence in the Magellan area of Chile has long been

Jan 1, 1988