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By David A. Lee

It was estimated in Chemical Week1 that the uranium fuel requirements for the U.S. Electric Utility Industry by the mid 1980's would be about four times that-of what it is today. This corresponds to approximately 45,000 tons per year of 'yellow cake' - of which a good portion is represented by ammonium diuranate - vs. the 11,700 ton total estimated for 1975. Perhaps just as significant is the 40-fold increase in thirty years projected for the entire world since 1970. Thus by the year 2000. 'yellow cake' production could be in the order of [3]50.000 short tons annually.2 'Yellow cake', so named because of its inherently bright yellow color, is a finely divided precipitate that can be formed after the leaching step when refining uranium ores. Feed solids enhancement then occurs to at least 50% by weight using filters or centrifuges This is followed normally by drying and then calcining with the conversion of ammonium diuranate to triuranium octoxide represented by the following equation: [9 (NH4)2 U2 07 heat 14 NH3 7 + 15 H2O7 + 2N2/ + 6 U308 4] Theoretically, assuming 100% conversion every 100 kgs. or 100 lbs. of ammonium diuranate will result in 90 kgs. or 90 lbs. of triuranium octoxide.

Jan 1, 1976

By J. Ye

A comprehensive flotation study has been carried out on a Chinese fluorspar ore using the packed flotation column developed at Michigan Technological University. The results are compared with that of a conventional mechanical flotation method on the same feedstocks. Key factors controlling flotation performance of both methods are evaluated based upon a simple statistic design. The flotation concentrate produced in one stage of the packed column has 4-S% higher recovery and much lower silica impurity content than that produced by up to six stages when a conventional mechanical cell is used. The results also show that the packed column flotation process is particularly suitable for recovery of finer fluorspar particles.

Jan 1, 1992

By L. G. Hendrickson

Direct-reduction processes for converting iron ores to metallic iron in the solid state have been available for some time; and whenever scrap becomes expensive, there is a new wave of interest in these processes. It is well established that direct reduction, coupled with electric-furnace steelmaking, is a technically viable method for making steel and in some circumstances is economically competitive with the conventional blast-furnace--basic-oxygen-process (BOP) route to steel. This raises a number of interesting questions, several of which could be of great interest to the coal and ore mining industries. For example, what are the quality requirements of the raw materials for direct-reduction--electric-furnace steelmaking? Would they be different from the present requirements for blast-furnace--BOP steelmaking? Other questions relate to how much steel will be made by the direct-reduction route in the future. The quality questions can be discussed with a fair degree of certainty, but a prediction of the amount of steel that will be produced by the direct-reduction--electric-furnace route is beyond the scope of this paper. However, an attempt will be made to identify some of the factors that will influence whether there is a swing to direct reduction and the rate at which it may occur.

Jan 1, 1978

By A. R. Bell

Rio Algom Limited are currently undergoing a major expansion of their mining operations in the Elliot Lake area. To date this has involved the increase of output at the Quirke Mine from 4080 to 6350 tonnes per mill day (4500 to 7000 tons), the rehabilitation of the Panel Mine to produce at the rate of 2990 tonnes per mill day (3300 tons) by 1980, and the rehabilitation of the Stanleigh Mine to produce 4540 tonnes per mill day (5000 tons) by 1984. In addition, the planning for the rehabilitation of the Milliken Mine to produce 4990 tonnes per mill day (5500 tons) is now underway. This major expansion is taking place at a time of increasing awareness of occupational health matters and has involved very high capital expenditures and detailed planning related to the ventilation system to endeavour the provision of an acceptable environment. The paper discusses the ventilation systems, established and proposed, and relates them to historical and current data on mine air contaminants.

Jan 1, 1980

The purpose of this talk is to report the answers to the-'two following questions: I. What unique services does the mining industry expect of mining and mineral processing engineers? II. What suggestions does industry offer to educators to help revamp curricula to meet the needs of a changing industry? As the result of many questionnaires filled out in person by presidents, managers, superintendents, chief engineers, metallurgists, and other responsible individuals in operations and management of large and small metal and nonmetallic mining companies in the U. S., and to some extent abroad, we now have some, specific answers to the above questions. Although answers to questionnaires continue to arrive at this writing (February 10) the volume already received is sufficient to clearly justify certain conclusions and observations. A copy of the tally of the first 117 questionnaires received accompanies this report, and I am certain that a compilation of additional questionnaire data will merely reinforce, the trends in thinking that have been' established thus far. Here are the results of the survey:

Jan 1, 1961

By E. Manev

Thin aqueous equilibrium film studies and surface tension measurements on a mixed surfactant system consisting of polyethylene oxide (a model frother) and potassium ethyl xanthate (a model collector) enable the interaction between the two surfactants at the air/solution interface to be elucidated. For the film containing the non-ionic frother, the interface was charged and addition of low concentrations of xanthate acted as a common electrolyte and reduced the thickness of the film inducing rupture. However, at high xanthate collector concentrations, the negative charge xanthate was found to interact with the non-ionic and caused a build-up of negative charge at the air/solution. Higher frother concentrations were necessary to produce non-rupturing thin films upon increasing the xanthate concentration.

Jan 1, 1992

By M. S. Celik

Salt-type minerals are usually floated with anionic and cationic collectors. Flotation of a number of systems has been reported to remarkably increase above the concentrations where surface precipitation of collector-metal salt is initiated. Some studies attribute this phenomenon to heterocoagulation of oppositely charged collector colloid and mineral particles. In this study, examples are given on boron minerals to demonstrate that the high flotation region occurs when particles, colloidal precipitates and bubbles acquire a similar charge which induces Van der Waals interactions resulting in hydrophobic bonding.

Jan 1, 1995

By H. W. Newcomen, D. R. Brox

Assessments of the stability performance of open pit highwalls have traditionally been based on consideration of surface movement rates. Although generally accepted in industry, this approach presents challenges for establishing appropriate threshold values to allow for safe mining operations and does not address the issue of total strain. Surface movement monitoring data from a limited number of open pit mining operations in North and South America has been evaluated in terms of highwall strain, rock mass quality and inferred mechanism of instability. Threshold strain levels for key stages of highwall stability proposed from previous work have been reviewed and are generally endorsed based on evaluation of additional data. An empirical highwall strain criteria for the assessment of highwall stability performance is postulated based on the observed trends in highwall strain data from the case histories presented.

Jan 1, 2004

By Joseph Matoney, B. K. Parekh

INTRODUCTION The term "dewatering" refers to removal of water from coal. Water associated with coal can be categorized as "free or surface" and "inherent or chemically bound" moisture.' The free moisture is found on the surface of coal, in capillaries and small spaces between two or more particles. The inherent or chemically bound water is found in the interior of the coal and as part of coal structure. A significant amount of free moisture can be removed by mechanical dewatering techniques. However, inherent moisture can only be removed by applying energy intensive techniques, e.g., direct or indirect heating. Moisture in the coal offsets some of the benefits of coal cleaning. Extra water in clean coal adds to extra cost in transportation, heat lost during vaporization, and plugging of chutes. From a utility perspective, a 1 % increase in moisture can offset a 4.5% decrease in ash.2 Mechanical dewatering can be classified into two major process categories according to the principles involved, namely, 1. Sedimentation-liquid is constrained and particles move freely. 2. Filtration-particles are constrained by a medium and the liquid flows through. Each of the process categories is composed of various separation techniques shown in Fig. Equipment currently being used by the mechanical dewatering of coal of varying size ranges and final moisture content is illustrated in Fig. 8-2. This figure indicates that sizes larger than 13/, in. (37.5 mm) present no particular dewatering problem. Shaker screens of the very crudest types and designs are capable of producing these sizes at low surface moistures. High-speed vibrators are used for the intermediate sizes and can be used for smaller sizes down to 0.02 in. (0.5 mm) if high moistures (15% surface moisture or greater) can be tolerated in the product. Usually, however, the vibrator is not used below 3/, to 3/, in. (9.5 to 6.3 mm) because of the moisture associated with these fine sizes. At this level, centrifugal force is usually employed to aid dewatering. Centrifuges of various types and designs are used practically

Jan 1, 1991

By M. I. Dobrynina

At the beginning of the 80-s the first diamond pipe in the East-European platform was discovered in the North of the Russian Federation on the White Sea Winter coast. During several years while studying this unique area data on kimberlites and country rocks petrophysical characteristics have been collected. Considerable experience in geophysical methods when searching and exploring diamonds was accumulated, and various methods of geophysical data interpretation were used. It has been established from the analysis of geophysical data that diamond-bearing kimberlites are located in the most ancient and the most stable block of the East-European craton.

Jan 1, 1995

By W. T. Caneer

Uranium may be in short supply due to the predicted energy needs in the coming years. As a result of this a new surge of uranium exploration is underway. The refinement of numerous exploration techniques has accompanied this surge. One such technique is the monitoring of radon gas in surface soils and rocks as a guide to subsurface uranium deposits. The Colorado School of Mines Research Institute became involved in radon studies in 1967 on a project for the AEC. Since that time the Institute has conducted numerous radon surveys for a large number of companies which have been active in uranium exploration. The objective of this paper is to relate the techniques utilized by the Research Institute and the results of some of the studies performed. Most of the studies performed by the Research Institute were related to roll front, sandstone -type uranium deposits. However, we have performed radon studies in various other types of rock. For those who may not be familiar with the application of radon ?sniffing" in soils and rocks, a brief descriptive background should be given. The following question may be asked -- why use radon as a guide to uranium mineralization? Some of the answers to this question are as follows:

Jan 1, 1974

By P. C. Miller

The paper reports laboratory results from the bioleaching of chalcopyrite ores and concentrates using a mixed moderate thermophile culture. Copper dissolution in excess of 95% was achieved in all cases with the majority of tests indicating copper dissolution in excess of 98%. Aspects of downstream processing are discussed in relation to iron rejection by precipitation. The laboratory results indicate the need for careful control of the pH value to prevent co-precipitation of the copper with iron. A comparison of capital and operating costs is given indicating potential differences between the use of toll smelting and bacterial leaching on site. A discussion is given highlighting the sensitive cost areas of these two process routes.

Jan 1, 1997

By K. Getsos

Western Greece is a favorable site for exploration and discovery of oil fields. The most important potential source rocks seem to be all the rocks deposited before middle Jurassic under special circumstances, such as reducing conditions, which allowed preservation and maturation of the organic material. In general all the rocks of middle Jurassic to Paleogene are not favorite source rocks. The porosity type was studied on fifty samples using scanning electron microscopy (SEM). Potential reservoir rocks are the porous Paleogene wackestones-packstones with boring, channel and vuggy porosity type. Finally seal rocks are the impermeable mud-stones and wackestones of Jurassic, Cretaceous and Paleogene age. These rocks consist of micrite and whole sells of foraminiferas and the porosity type is mainly intercrystal/interparticle. A Total Organic Carbon (TOC) analysis, conducted on seventy samples using a wet oxidation method, has revealed an extremely low TOC content (less than 0.05 %). This amount is by far less than the minimum organic content amount, required for source rock characterization and characterizes all the rocks of middle Jurassic to Paleogene age. Additionally, 18O and 13C stable isotope analysis was contacted and the results are given in d values. All the rocks within the studied time interval have much lower d values than petroleum source rocks. Clay mineral content was studied in almost seventy samples. As is indicated by the clay mineral content the studied rocks have reached up to the Middle Diagenesis and the temperature during diagenesis was rather low.

Jan 1, 2006

By Raul A. Deju

This paper shows how one can relate the chemical reactions between water and a silicate bed to the equations of flow. First the reaction mechanism is studied both theoretically and experimentally. Once the reaction mechanism is established, the equations of flow are solved and a solution (under physically reasonable side conditions) is obtained. Experiments to substantiate the solution are also presented.

Jan 1, 1969

By S. C. Termes

As part of an effort to provide basic data on the fundamental scientific and engineering principles of minerals beneficiation, the Bureau of Mines is conducting research on the flocculation of mineral fines. This paper presents results of studies using crosslinked starches containing carboxyl, diethanolamine, iminodiacetic acid, and xanthate groups to flocculate hematite, goethite, chromite, manganrte, pyrolusite, cuprite, and cassiterite fines. The carboxyl and xanthate derivatives flocculated all minerals except cassiterite; the latter was flocculated by only the diethanolamine derivative. The iminodiacetic acid derivative flocculated hematite, goethite, chromite, cuprite, and pryolusite fines. Zeta potential measurements were made to help define the reaction mechanism responsible for flocculation. These measurements indicate that electrostatic attraction probably is not involved, except possibly in the case of the diethano lamine derivative. The separation of hematite from quartz by selective flocculation with chelating cross- linked starches under two pH conditions and with two dispersing agents is described. Best recoveries and grades were found when either the carboxyl or xanthate derivatives was added at the natural pH of the pulp in the absence of a dupersing agent.

Jan 1, 1983

By Shawn P. Coughlin, Michael A. Schimmenti, Juan Leonardo Tello del Pino

"PROJECT OVERVIEWThe Sistema de Potabilización Área Norte project (Northern Area Purification System) was a major expansion of the potable water system in Buenos Aires Province, Argentina. The aim of the project was to transport and purify raw water from the Paraná River to provide potable water for five communities in the northern part of the province, benefitting up to two million inhabitants. The project was constructed by a joint venture of four South American contractors (“the JV”), and consisted of the following key components:• Treatment Plant: A 16 hectare area was cleared for the construction of a treatment plant to purify 900,000 m3/day of raw water from the Paraná River and distribute it to the surrounding communities.• Bored Tunnel: Nearly 15 km of 3.6 m inner diameter tunnel, ranging from 18 to 22 m below grade, was bored with two EPB tunnel boring machines to draw the raw water from the river. The TBMs started from a central launch shaft and proceeded in opposite directions: Cristina advanced northbound to the Paraná River Intake System, and Liliana advanced southbound to the new treatment plant.• Access & Ventilation Shafts: Five access shafts and eight ventilation shafts were installed along the length of the tunnel. The access shafts were designed to provide entry points for inspection and maintenance of the final tunnel. The five shafts consisted of: one central launch shaft in the middle of the tunnel alignment, one retrieval shaft at each end of the tunnel (Intake and Treatment Plant, respectively), and two intermediate shafts. The intermediate shafts were installed before the TBM passed, with a final liner to be installed afterwards. Access Shaft 3, the intermediate shaft located between the launch shaft and the treatment plant, experienced persistent leaks during initial excavation attempts."

Jan 1, 2016

By Robert J. M. Miller

Thank you Mr. Chairman. For more than 15 years a debate has been taking place among students of massive sulphide deposits as to the origin of these deposits. Prior that time it was widely accepted that the deposits were of hydrothermal, epigenetic and even replacement origin (Wilson, 14). Kinkel, Knight, Stanton and others advanced hypotheses which would explain the, formation of the deposits by different, largely syngenetic, volcanogeric processes. I was fortunate in having become involved in exploration for these deposits at about the time the debate was beginning and thus had an opportunity to apply with some success, some of the new and old ideas for formation of massive sulphide deposits. The deposits which I will discuss today are all located n northwestern Quebec, in the Abitibi orogenic belt. Mattagami Lake Mines is about 100 miles due south and Noranda's Horne Mine about 200 miles south of James Bay. In 1959 I prepared a talk which was presented to the 1960 CIM Convention calling attention to the spatial and possible genetic relationship between the ore sulphides of the Mattagami Area, Quebec and the tuffite, as well as the structures which controlled the ore. In this present paper I would like to cover the following points: (1) The general criteria used by the epigeneticists to support their contention that the deposits were formed after the enclosing rocks.

Jan 1, 1973

By J. J. Kellar

The near-infrared (NIR) (12,000-4,000 cm-1) region of the electromagnetic spectrum, between the mid-infrared and visible, has often been viewed by spectroscopists to be of limited utility. This is unfortunate, and recently the use of the NIR has increased greatly, primarily for the quantitative analysis of food and agricultural products. However, many other areas of application of NIR spectroscopy remain unexamined. In this paper a novel use of NIR in the area of flotation chemistry is demonstrated. Specifically, it is shown that NIR/Internal Reflection Spectroscopy (IRS) can be used to quantify collector adsorption reactions in-situ.

Jan 1, 1990

By J. J. Gusek

An 81 hectare (200 acre) tailings impoundment at a taconite operation in Wyoming that ceased operations in 1983 has been a source of blowing dust. The site qualified for reclamation under Wyoming's Abandoned Mine Land (AML) reclamation program. The ultimate reclamation construction included: incorporating commercially available organic amendments and fertilizers into a 300 mm (12 in) thick "cap" of a sterile clay loam cover material, lowering the water level in an adjacent flooded mine pit that was feeding uncontrolled seeps into the tailings basin, constructing a wide tailings pond spillway that allows flood control while minimizing seasonal water level fluctuations in the pond, and building rock berms and rock snow fences for wind erosion control and soil moisture preservation. Tree planting in the protective wind/snow shadows of rock berms and rock snow fences, and the plugging of a decant pipe are planned for future work.

Jan 1, 1998

By G. Davis

Mineral properties and mineral firms often trade at a market value that is significantly greater than the value indicated by discounted cash flow (DCF) techniques. A possible explanation is that DCF analysis does not consider the value derived from managerial flexibility. Presumably, then, at least some of the difference between DCF value and market value is due to managerial flexibility. This paper surveys the recent attempts to empirically quantify the value of managerial flexibility using option pricing theory. The results indicate that managerial flexibility, at least as measured by the option pricing methodology, falls well short of explaining the gap between DCF value and market value.

Jan 1, 1995