Search Documents

By P. G. Vikre

Several factors have caused less emphasis to be placed on geologic mapping in mineral exploration in the last 15 years. These include opportunities for "easy" discoveries of near surface gold and silver deposits in developed countries, and of base metal deposits as well in less developed countries, a decline of emphasis on geologic mapping in many universities, and a decline of useful mapping by government agencies in many areas. Geologic mapping is simply a way of recording geologic observations on volumes of rock larger than can be seen from one place. Since most geologic processes involve systems larger than this, mapping is also essential to understand the significance of observations made on smaller volumes of rock, such as thin sections and sample taken for chemical or isotopic analysis. To be useful, the observations recorded through geologic mapping are then interpreted to arrive at an understanding of the 3D geometry and geologic history of a volume of rock, which is used to direct mineral exploration, or any number of other purposes.

Jan 1, 1995

By J. Jordan, D. K. Denton, D. Tesarik, D. F. Scott, T. J. Williams

Personnel from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health integrated the results of studies from a seismic tomographic survey, a finite-difference analysis, laboratory measurements of compression wave (ultrasonic) velocities in rock cores, and site geology to evaluate the use of seismic tomography for identifying induced pressures in an underground pillar at the Edgar Mine, Idaho Springs, CO. The key findings were that (1) the seismic tomograms showed that seismic velocities in rock adjacent to mine openings were low, (2) a difference tomogram in which in situ stresses on the east and west sides of the slot were compared showed that velocities increased west of the slot but decreased east of the slot, (3) geologic features (rock types and a fault) identified through geologic mapping were recognizable in the seismic tomograms, (4) ultrasonic velocity measurements on the rock cores agreed with seismic velocity measurements in the tomograms, and (5) results from a finite-difference analysis compared well to the seismic tomograms west of the slot but not east of the slot. The significance of this research is that seismic tomography is a useful tool for determining relative stress in underground pillars.

Jan 1, 2004

By Roy A. Koski

This paper describes variations in feed characteristics, preparation techniques, response to induration and product quality in pelletizing magnetite concentrates, earthy hematite ore fines, and specular hematite concentrates in grate kiln systems. The Cleveland-Cliffs Iron Company manages plants processing these various materials on the Marquette Iron Range in northern Michigan. The operations include the Humboldt Mining Company, Marquette Iron Mining Company, Empire Iron Mining Company and the Pioneer Pellet Plant. The combined output of the operations is approximately 9,000,000 long tons per year. The Humboldt Mining Company, owned by Ford Motor Company and Cliffs, produces pellets from a specular hematite concentrate. The Empire operation, which processes magnetite ore, is owned by Inland Steel Company, McLouth Steel Corporation, International Harvester and Cliffs. The Pioneer operation, which processes earthy hematite ores, is a joint venture of Republic Steel Corporation, McLouth Steel Corporation, Bethlehem Steel Corporation and Cliffs. The Marquette Iron Mining Company, owned by hones and Laughlin Steel Corporation, International Harvester, Wheeling-Pittsburgh Steel Corporation and Cliffs, produces pellets from specular hematite concentrate at the Republic Mine and Eagle Mills Pellet Plant. With the exception of the Eagle Mills plant, the operations employ the grate-kiln pelletizing system. Descriptions of the Empire, Pioneer and Republic operations, which have a combined capacity of 7,200,000 tons per year, are given in the paper.

Jan 1, 1969

By G. F. Joklik

Although the mineral shortages of twelve to eighteen months ago have given way to oversupply, their memory lingers on. These problems were man-made: booming demand throughout the industrial world, political and industrial unrest and the oil embargo all contributed. But in the minds of many, the shortages conjured up visions of the depletion of the world's mineral resources, a disaster that could be staved off only by drastic curbs on consumption and therefore, curbs on economic growth. A little historical research shows that fears such as this are not inventions of the 1970's. A hundred years ago, for example, the imminent exhaustion of the world's coal supplies was being predicted in Great Britain. The English economist, John Stuart Mill, who was usually more perceptive, wrote a few years earlier that "it is only in the backward countries of the world that increased production is still an important object". And later there was Franklin Roosevelt who said in 1932, "Our industrial plant is built; the problem just now is whether under existing conditions, it is not overbuilt". His concern, in other words, was not with the discovery and exploitation of new natural resources, but with the administration of known resources and with seeking foreign markets for surplus production. In light of copper prices at the time -- just under 6¢ a pound -- that was understandable. These instances illustrate how, throughout the world's industrial history, concern about surpluses of raw materials has alternated with alarm about the adequacy of supplies and with calls for restricting growth.

Jan 1, 1975

By Margreth Tadie, Chalwe Chibwe

Physicochemical properties of copper electrolytes are a strong fundamental consideration in electrodeposition processes during electro-purification and recovery of copper. Their influence extends to mass transfer as well as energy consumption during the electrodeposition process. In this study, the influence of electrolyte composition on electrolyte physicochemical properties was investigated to review the existing literature data. This review of data is considered necessary as more and more electrowinning models are being developed for process prediction and optimisation and a need of such data is required for accurate prediction of physicochemical properties. The major components of importance to the formation of smooth high-quality and high-purity copper cathodes at optimum current efficiency are considered the species in solution. These include Cu ions, Fe ions (major impurity), H2SO4, and a smoothing agent additive. A 5-factor, 2- and 3-level experimental design was employed to determine the effect of copper (35 and 45 g/l), sulphuric acid (160 and 180 g/l), iron (1, 3, and 6 g/l), polyacrylamide additive (2, 5, and 10 mg/ l), and temperature (45 and 55 °C) on electrolyte density, conductivity, and the diffusion coefficient in synthetic copper electrowinning electrolytes. The major species in a copper electrowinning electrolyte are found to be the most relevant for prediction of physicochemical properties. These results indicate that relatively simple empirical models are sufficient for modelling of the electrolyte domain in electrowinning, without the need for the generation of vast amounts of complex experimental data.

Feb 1, 2021

By J. V. Belke

There are many aspects of a grinding mill supply and installation that can result in the mill not operating as intended, resulting in unplanned shutdowns, poor reliability and headaches for all concerned. One of the largest aspects, both in criticality and physical mass, is the mill foundation; if not properly specified, designed and constructed the mill operation will be compromised. The mill foundation starts with the design specification and loading diagram supplied by the mill builder. The importance of understanding these documents and how to apply them is critical for the start of any mill project. When designing mills with a GMD the foundation must be properly modeled to ensure that all interactions of the mill and motor structures, foundation and subsurface strata behave in the intended fashion. All of the previous efforts can be laid to waste if the construction of the mill foundation is poorly handled. Mill foundations are typically the most massive concrete structure at a processing plant and can easily cause nightmares for inexperienced contactors. This paper explores some of the more important facets along the lifecycle of the grinding mill foundation.

Feb 23, 2014

By A. Hajati

The main purpose of this study was to find the optimum values for factors affecting the Zn recovery rate using oxine or dithizone as a chelating agent collector during flotation in a Hallimond tube. Eight control factors, including four levels of pH, oxine/dithizone, corn starch, sodium thiosulfate, sodium citrate, sodium silicate, conditioning and floating durations were considered in a Taguchi experimental design technique. An L32 orthogonal array was applied to determine the signal-to-noise (S/N) ratio. Analysis of variance (ANOVA) was used to determine the optimum conditions and the most significant parameters affecting the reaction rate. Analysis of the experiments using the Taguchi approach indicated that pH had the highest contribution to the recovery rate of zinc oxide particles. The results showed that the recovery rate of zinc increased by 43.4 ± 3.0% and 24.9 ± 3.2% using oxine and dithizone, respectively, under optimum conditions with a confidence level of 90%.

Jan 1, 2010

By E. Martinez

A heavy mineral sand sample was tested containing 13% heavy mineral consisting of rutile, zircon, and ilmenite. Eleven tests were run at a mill site with a Mineral Deposit Limited MG 4 spiral to determine the effect of the addition 0; magnets to the spiral compared to conventional gravity separation. Different magnet configurations and field strengths were tested. Optimum results were obtained with the spiral retrofitted with magnets. The heavy mineral content of the concentrate was increased from 55.5% in the control to 64.2% with the magnets. The 8.7% improvement in heavy mineral recovery was due not only to the weakly-magnetic ilmenite, but also to increased recoveries if the non-magnetic zircon and rutile. The increased recoveries were achieved with no loss of concentrate grade.

Jan 1, 1992

By M. J. Hrebar

In the summer of 1990, a study was conducted to document large tractor (i.e., Caterpillar Dl1N) utilization in surface coal mining. The tractors were found to be utilized as primary production machines and in combination systems with blast casting and draglines and blast casting and excavator/truck systems. In addition, dozers were used to prebench ahead of a primary dragline system. The study also established ranges and averages for Dl1N operating costs and mechanical availability. Based on simulated production of various tractor dozing applications, the potential for low cost coal stripping was suggested (Hrebar, 1991). A follow-up study, also funded by Caterpillar Inc., was conducted in the summer of 1991 to determine actual production rates in two dozer stripping applications. These actual production rates would then serve as a foundation for estimates of stripping costs. This paper presents the results of the studies in a contour and a cast application.

Jan 1, 1992

By T. Rudolph, M. Pawlik, J. Benndorf, X. Yin, J. F. Brune, P. Goerke-Mallet

The long and often undefined period in the post-mining phase challenges geo-monitoring with its various responsibilities, like the detection of environmental changes, ground movements and water management. Modern methods of geo- and environmental monitoring observe numerous aspects using active and passive sensors with multispectral, hyperspectral and microwave sensors, with diverse spatial dimensions and spatiotemporal resolutions from satellites, Unmanned Aerial Vehicles (UAVs), in-situ sensors. Data integration, together with on-site knowledge and experience, provides the basis for comprehensive modeling, which improves the understanding of the environmental changes and their related causes, which is an essential step for public acceptance. In this paper, we aim to give a brief overview of various geo- and environmental monitoring methods.

Mar 2, 2022

By R. M. Rowe, T. E. Irwin

A flowsheet was developed for upgrading Climax tin concentrate to about 45 percent Sn. Bench-scale test work conducted at AMAX Extractive Research and Development, Inc., was used to design a multiple-stage tin- processing flowsheet which included screening, high-intensity magnetic separation, and high- tension (electric- static) separation. Formal engineering and plant installation was accomplished in-house by Climax mill personnel. The successful start-up operation of the facility was the joint effort of the AMAX R&D and Climax-mill staffs.

Jan 1, 1986

By Jonathan G. Price

Silver-copper-lead deposlts in Precambrian, Permian, and Cretaceous red-bed sequences near Van Horn, Texas, have the following features In common: (1) mineralization controlled by steeply dipping fractures in sandstones, (2) lack of ore In overlying and interbedded limestones, (3) absence of igneous intrusions, (4) sulfide ores without typical hydrothermal gangue minerals, and (5) associated arsenic, molybdenum, zinc, and cadmium but not gold. Ore was probably deposited along fractures by reaction between low-temperature, oxidizing, metal-rich ground waters and sulfide-bearing waters or rocks. Detailed mapping and studies of fracture patterns indicate that mineralization occurred during Basin and Range extensional deformation, thereby postdating major Trans-Pecos igneous activity.

Jan 1, 1983

By J. Philip Bromberg

The 1977 Clean Air Act Amendments will have a large effect on the coal-fired segment of the electric utility industry. Since electric power generation constitutes by far the largest single use for coal, this legislation has the potential to greatly affect future patterns of coal utilization in the U.S.A. The inability to depend exclusively upon low sulfur coal as an exclusive mode of compliance with New Source Performance Standards may greatly lessen projected demands for low sulfur coal by eastern utility boilers. The requirements of the legislation is discussed with particular reference to the needs of the electric generating industry, along with the technologies available for complying with the Act.

Jan 1, 1978

By J. Y. Hwang

Sands are utilized to make molds for metal castings in the foundry industry. Approximately a half ton of sand is disposed of for each ton of metal cast in this country. In Michigan, annual sand disposal amounts to about one million tons. A process has been developed in this study to reclaim sands from a steel foundry. Physical separations are utilized in conjunction with other operations (such as the removal of binder, metal, spruce, washes, etc.) to yield silica and chromite sands with desirable molding properties. Several different separation methods, including electrostatic, magnetic, and various gravitational approaches have been examined. Experimental results are presented. The applicabilities of these separation methods are discussed.

Jan 1, 1992

By I. M. Arbuthnot

Over the last five years, a large number of small to medium sized carbon-in-pulp gold treatment plants have been built in Australia, most designed to treat between 250,000 -1,500,000 tpa of ore. In many cases, the primary requirement was to get a plant built and operating in a short period of time and at minimal capital cost, relating to the limited capital resources and tight cash flow positions of these relatively small mining companies. Since the inclusion of both pre-leach and tailings thickeners resulted in an obvious and significant capital cost, most plants were built without thickeners, without doing a detailed cost-benefit analysis on their inclusion, However, the increasing use of High Rate Thickener?s (HRT s) in the mineral processing industries resulted in a reassessment, in some cases, because of their considerably lower cost. This reassessment was triggered primarily by the need to conserve water in arid mining areas, where borefields were costly to install and water was limited. It has become apparent, though, since startup and operation of these installations, that the savings in cyanide consumption is also a very significant factor and can be used as a primary justification for the installation of a HRT in many cases.

Jan 1, 1991

By P. Rusin

Toxic substances in On solutions can retard biological leaching of copper sulfide dump ores. On solutions were analyzed for metals, organics, and chloride, and showed inhibitory concentrations of aluminum, manganese, and chloride. Inhibition of bacterial activity by the solid fraction of On solution, with and without the organic constituents, was evaluated. Toxicity to bacterial species was evaluated by monitoring bacterial numbers, pH, Eh, and rates of iron oxidation. The On solution solids were toxic at 50 -60% of their field concentration. Most of the toxicity of the On solution was due to the organic fraction. Different SX reagents show varying degrees of inhibition of T. ferrooxidans. Bacterial inhibitory effects of carriers and lixiviants used in the SX plant should be determined so that entrained SX reagents do not retard biological dump leach systems. The reagents used should be the most cost effective and the least toxic.

Jan 1, 1994

By S. S. Wang

Dialkyldithiophosphinates are a new class of flotation collectors for base metal sulfide ores. Structurally, they are quite different from the conventional collectors such as mercaptans, xanthates, thionocarbamates and dithiophosphates. Collectors Structures [Mercaptans R-SHS Xanthates R-OCS-M+ Thionocarbamates R-OCNH-R Dithiophosphates 2 R-CCNH-R' Dithiophosphinates (R) 2-PS-M+ ] In the above structural formula, R and R' stand for a hydrocarbon radical, and M+ is an alkali metal or ammonium cation.

Jan 1, 1982

By Libby R. Ricafort, Nonato S. Retardo, Jose B. Anievas

This paper shows the metallurgical test results that led to the design of the heap leach facilities of Philex Mining Corporation. The design incorporates a water management model as process solution circulation is excessive with high rainfall intensity in the area. This poses problems in the operations requiring stringent controls than would be necessary in a less severe environment. The corporate perspective embraces on environmentally-sound mineral development. A budget is always provided to environmental management making certain that no industrial development is moved forward at the expense of the environment.

Jan 1, 1996

By Tony Dunn

FMC Corp. achieved a significant cost reduction at its Green River, WY soda ash operations using a new proprietary solution-mining and processing technology. In phase one of the program, trona ore is dissolved, recovered and processed with the new technology. It is then fed into an existing refining plant, replacing dry mined and calcined trona ore. Phase two produces a final high-purity product. It also increases capacity by 635 kt/a (700,000 stpy). Both phases were completed under budget and ahead of schedule. This $120-million expansion project uses a new process and a new team to derive soda ash in a more cost-effective and environmentally friendly manner. The team successfully introduced solution-mining technology - with a liquid solution injected into previously mined sections of the mine. This shift in techniques signified a new era for soda ash production. The project is an example of teamwork at its best. For it to be successful, FMC had to work within several different areas inside and outside of the company. Engineers, contractors, mechanical operators and technical people were needed who could blend in with FMC's existing in-house team.

Jan 1, 1999

By L. Xiao, P. Somasundaran

Using potassium oleate as a collector and alizarin red S as a modifying agent, selective depression of dolomite from francolite was achieved in an alkaline medium (pH > 9.0). Adsorption of alizarin reds alone on dolomite was found to be higher than that on francolite. Complimentary adsorption experiments of alizarin red S and oleate showed that oleate adsorprion was increased in the presence of alizaring red S. The results are explained in terms of comparative adsorption for the active sites on francolite and dolomite by oleate and alizarin red S and their interactions with dissolved mineral species in solution.

Jan 1, 1990