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By B. J. Scheiner

A ferrous chloride-oxygen leaching system was investigated by the Federal Bureau of Mines as a means of re-covering copper and silver from a sulfide concentrate that had been pretreated to remove a majority of the antimony. The pretreated concentrate contained Cu, Ag, Pb, Zn, Sb, and As. Parameters affecting metal extraction, such as temperature, pressure, amount of ferrous chloride, and initial hydrogen ion concentration, were studied. Copper extraction of 98 pct was achieved by leaching 4 hours at 40 pounds per?square inch gage (psig) and 1000 ?C. Copper was recovered from leach solutions by cementation with iron, and the resulting ferrous chloride was recycled. Leaching the residue with cyanide followed by electrowinning recovered 99.7 pct of the silver. Iron, Sb, As, Pb, and S reported to the tails.

Jan 1, 1978

By S. B. Kim, J. Hong, K. Park, W. Kim, H. Kim, Y. Han, J. Choi

"For the first time, the influence of stearyl trimethyl ammonium chloride (STAC) as a collector, on the flotation behavior of lepidolite (Uljin, South Korea) was systematically examined in Denver Sub-A cells. Flotation tests were carried out by varying amount of STAC (50–200 g/ton), feed size (-65, -100, -150, and -200 mesh), and solution pH. The impeller speed of 1000 rpm, flotation time of 10 min and AF-65 (a frother) of 250 mL/ton were invariably applied. In order to complement flotation experiments, zeta potential measurements and XRD analysis were conducted. XRD results showed that the ores were mainly composed of lepidolite, muscovite, quartz, calcite and albite. In addition, zeta potential results showed that isoelectric points were about 2.5, 2.3, and 9.7 for quartz, albite, and calcite, respectively, and lepidolite was determined to be less than 2. Overall, the results of 3-stage flotation showed that Li2O grade and recovery tended to increase with increasing STAC dosage and decreasing feed size. In addition, Li2O grade increased with decreasing pH. The results were explained by the extent of the interaction between STAC and each mineral.INTRODUCTION A great number of potential applications of lithium are being developed currently by the thermonuclear fusion power generation industry(1,2) as well as by the battery and fuel cell industry(3). Even though lithium is mainly consumed in the form of lithium metal and some lithium compounds, about 10% of total lithium production is consumed directly as mineral concentrates by the ceramic industry for the manufacture of special ceramics and mica based glass-ceramics(4). Granitic pegmatites normally contain feldspars, quartz, and mica in addition to lithium-bearing minerals such as spodumene (LiAl(SiO3)2), petalite (LiAlSi4O10), and lepidolite (KLi2Al(Al,Si)3O10(F,OH)2). The amount and grade of metallic minerals tend to gradually decrease and become lower, leading to the increase in the price of base metal or metallic compound(5). Accordingly, recent studies have been extensively devoted to developing the technique to improve the grade of metallic minerals from low grade metallic ores(6,7). Nevertheless, studies regarding the improvement of Li grade from lepidolite ores are very scarce. Lepidolite is a phyllosilicate mineral of the mica group and is often associated with other minerals such as calcite, muscovite, feldspar, and quartz, which need to be separated for lepidolite enrichment(8). Many studies have reported the flotation techniques for separating calcite, muscovite, feldspar, and/or quartz from various targeting minerals(9-11); however, there has been no attempt to investigate physico-chemical properties of lepidolite and its separation from such types of gangue minerals through flotation. Hence, in this study, for the first time, flotation has been carried out for the quaternary ammonium salts (stearyl trimethyl ammonium chloride (STAC, (CH3)3CH3(CH2)16NCl))-lepidolite system based on only the electrokinetic property of minerals that consist of lepidolite ores without adding any depressant to get an initial insight on its flotation behavior. The experimental variables that influence the lepidolite flotation such as amount of collectors, feed size and solution pH have been also examined."

Jan 1, 2015

By Sadatoshi Ohmori, Karen Shinoda, Nobuharu Isago

Method of tunnel excavation is generally classified such as full-face excavation, bench-cut excavation, diaphragm with center pillar excavation, center drift advancing excavation and so on. These excavation methods should be selected properly in terms of ground condition, the area of tunnel section, the arrangement of construction. Center drift advancing excavation method in mountain tunnel construction, is often applied under quite weak ground condition, prior to the main tunnel widening excavation. Recently, the advancing drift is for the excavation of extreme larger section in main tunnel to confirm the stability of face. In addition, we make advancing deformation occur in drift when the construction was done in poor ground like squeezing and swelling ground, and the force occurred in main tunnel was expected to reduce by the effect of ‘dodging’ for support structure. Mechanical relation between drift and main tunnel has been mainly grasped on past experiences in Japan. However, the characteristic of tunnel enlargement was partially discussed by using the three dimensional analysis and the result was grasped by past experiences on the basis of each tunnel construction. It is considered that the natural ground stress is normally released as the advance displacement, but it was released after the main tunnel widening, causing a displacement and deformation increase. Up to now, the construction practice has shown the reduced displacement during the main tunnel widening excavation by the drift, and the numerical analysis agreed with above observation. However, there is no report found that the displacement and deformation at the time of widening excavation of the main tunnel become larger in case of a drift application. In Kyusyu area, western part of Japan, the northern part of Yoshinomoto tunnel was applied an advancing bench-cutting method for a center drift for the purpose of obtaining the geological information for support selection of the main tunnel in widening excavation. The shape of center drift was a perfect circle with a diameter of 4.0 m or 6.0 m and the same temporary support regardless of the geological situation. As a result, the displacement and deformation of the main tunnel after widening excavation were larger than the section where the center drift was not applied. Furthermore, the displacement and deformation of the main tunnel after its widening excavation was considered larger in the section where the cross-section of the center drift with 4.0 m diameter was applied than one with 6.0 m. Therefore, the center drift with a high rigidity support structure had the effect of suppressing the advancing deformation prior to the main tunnel widening excavation.

Jun 13, 2021

By Charles U. Keranen

The Tilden Mine is an iron ore mining, processing and pelletizing facility located on the Marquette Iron Range in Michigan's Upper Peninsula. It has a designed capacity to produce 8 million long tons of pellets annually from 21 million long tons of crude. It is a partnership owned by The Cleveland-Cliffs Iron Company, Algoma Steel Corporation, LTV Steel Corporation, the Steel Company of Canada, Wheeling Pitts- burgh Steel Corporation and the Sharon Steel Corporation. Cleveland- Cliffs manages and operates the Tilden. The crude ore averages 35% iron and is primarily non-magnetic iron oxide and silica. The major ore mineral is martite. Hematite, earthy hematite, goethite and magnetite are also present. The principal gangue mineral is chert. The ore grains are mostly in the 10 to 25 micron size range which necessitates very fine grinding for liberation. The concentrating process is the most complex one used in the iron ore industry. The unique technology for Tilden was developed in the mid and late 60's. The design and construction occurred in the early 70's and operation of the first phase which was of 4 MLTPY capacity began in October. 1974. Expansion of the facility to the current 8 MLTPY capacity was completed in 1979. Chemicals are the key to the beneficiation process at the Tilden Mine. The flowsheet utilizes selective flocculation - desliming, cationic silica flotation and concentrate dewatering by thickening and filtering. Nine different process chemcals are used. The control of the reagent feed systems is highly auto- mated. The entire concentrator is operated from a central control room. The concentrator flow diagram is presented in figure 1. The plant consists of 12 primary autogenous grinding lines, a common crushing circuit to handle an intermediate product within the primary grinding section, 24 pebble mill lines with cyclones and deslime thickeners, 12 flotation lines, 4 concentrate thickeners and slurry tanks, 8 lines of filters with six machines per line, and 2 tailings thickeners. A pumping system was installed in 1980 to permit the direct return of tailings thickener overflow water back to the reuse water pumphouse.

Jan 1, 1986

By E. L. Bohnet

The purpose of this paper is to translate a mining company's "Corporate Objectives" into usable and practical guidelines for long term mine design and production scheduling. These guidelines are required to ensure that both operating and development properties are designed and economically ranked on the same basis, and with the "current" Corporate Objectives in mind. Secondly, if both management and mining engineers have a better understanding of the cause and effect of corporate policies, then penalties and risks associated with various Corporate Objectives can be put into better perspective for management. Corporate Objectives, relative to usable guidelines for either short and/or long term mine planning, could be defined as one or more of the following four objectives: 1) Maximize the recovery of the economic portion of the defined geologic resources, and hence, maximize total non-discounted project cash flows and profits (most common approach in mine design), 2) Maximize the Net Present Value (NPV) of the after-tax cash flows from each existing or proposed project, either on an individual basis or in concert with other projects, including downstream processing facilities (primary method used to judge relative investment merit of a proposed development or operating concept), 3) Limit short and long term capital expenditures to a defined ceiling, 4) Maximize product output for the existing facilities in the short term, or conversely, keep commodity production at a constant level for a series of years.

Jan 1, 1994

By R. M. Geisenheyner

We are in the midst of a transportation revolution. From the Wright Brothers to the SST. From the Toonerville Trolly to the 120-mile-an-hour Northeast Corridor train. From Christopher Columbus to Neil Armstrong. There is another side to this revolution and it is going on every day at our mines and factories. We call it bulk distribution. Perhaps ordinary sounding, but every bit as exciting as those other transportation innovations. Basically, we have gone from bag to bulk, and in the process reached that Last Frontier in manufacturing cost savings. By revitalization of our distribution system, we have made it possible for our mines and factories to realize fully the vast economies of spage-age manufacturing techniques and accomplishments. The pacesetters in this distribution revolution have been you gentlemen, the producers and shippers of dry mineral products. In this area bulk distribution grew up. And here most of the current innovations are being introduced. Management of your industry was early to realize the economic advantages of bulk distribution. Distribution costs of your products comprises a sizeable, portion of the selling price and management is sensitive of any developments which may even slightly reduce the cost of transportation, marketing or the exploration of new frontiers.

Jan 1, 1969

By E. Harrison

The Greens Creek Ore Bodies are located approximately 18 miles southwest of Juneau, Alaska in an area on Admiralty Island classified as a non-wilderness national monument. An area-wide stream sediment geochemistry program targeted the deposit in October of 1973. Today, after 37,000 meters of combined surface and underground diamond drilling, three ore zones are known to exist with total reserves approaching 4.1 million tonnes. Lying within moderately folded metasediments of an undetermined age, these orebodies are thought to be of seafloor exhalite orgin and contain unusual and impressive amounts of gold, silver, lead, zinc and copper.

Jan 1, 1986

By M. Misra

A sample of thorium-contaminated soil from Kirtland Air Force Base (AFB) was subjected to froth flotation for removing thorium contaminants. A series of flotation tests were conducted to screen and evaluate the reagents. Among the collectors used, sodium oleate exhibited to show the promising results. Preliminary tests showed that a concentrate having activity as high as 5300 pCi/g can be obtained from the contaminated feed soil having activity 800 pCi/g. The volume reduction obtained was 89% and the activity recovery in the concentrate was 68%. The paper discusses the physico-chemical characterization data and the potential physical separation decontamination schemes for the thorium contaminated soils.

Jan 1, 1996

By T. M. Yegulalp

A numerical model is being developed to assess the enhancement of permeability by improved fracture connectivity by micro-hydrofracturing. A generic two-dimensional percolation model has been developed to test the impact of various field conditions on permeability. Field data from Cyprus Minerals' Mineral Park Mine has been used to establish statistical properties of the observed fracture systems. Results of statistical anlyses of the field data and examples of the use of percolation model are presented.

Jan 1, 1995

By R. D. Irvine

Enhanced concern for protection of the environment and attendant actions by environmental regulatory authorities in support of this concern are influencing to varying degrees the demand and supply of a range of industrial minerals in a number of jurisdictions. These influences take a variety of forms. In this paper, the author seeks to delineate certain broad trends which are occurring relative to industrial minerals and the environment and then, through a series of examples, outline opportunities, developments, and impacts respecting a number of industrial minerals produced and consumed in Canada and the United States.

Jan 1, 1995

By B. E. Davis

A technique was devised by the Bureau of Nines to recover coarse (plus 1.7 m) 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 17.0-pct-P205 reject to 24.5 pct P205 with a phosphate recovery of 63 pct.

Jan 1, 1985

By Roshan B. Bhappu

Based on the classical definition of optimization, flotation plants of today are far from being perfect, effective, or functional as possible. Though considerable efforts have been expanded in the optimization endeavor during the last decade, much more needs to be done in the future to optimize our flotation plants and operations. The major problem in designing an optimum flotation circuit is that the flotation process depends on the interaction of several physical and chemical parameters. In the past, there has been a tendency to only consider the effects of chemical factors such as flotation reagents: collectors, frothers, conditioning reagents, pH, etc. On the physical side, the emphasis has been limited to the liberation characteristics, grinding time, percent, solids in the pulp and flotation time. Its only recently that we are employing particle size analyses, on-stream analysis, oxidation reduction potential and the like, as operating controls. The design, operation and control of a mineral processing plant depends on costs incurred at all stages, from inception (testing for flowsheet development) through plant closure and beyond. To ensure that micro- and macro- engineering technology is transferred to operational levels, the academia, testing engineers, designers, operators, consultants and management must all get involved in the transformation process. Historically, in the 1950’s engineering empiricism was strengthened through micro-engineering based on fundamental and mechanism. Unique scientific apparatus such as zeta meter and infrasizer were used to test new hypotheses. With the advent of computers in the 60s and 70s, complex differential equations were solved to study and understand unit processes and to assess mechanism assumptions. Such efforts contributed to improved understanding of the unit operations such as comminution, flotation, thickening, filtration and the like. In the 80s and 90s with the availability of more sophisticated computer technology involving modeling procedures, advanced numerical methods, image analysis, nonlinear-curve-fitting and data adjustments, it was possible to test newly developed models under the production environments. These innovations are now available to develop simulator and sensors (such as particle size analyses) for macro-engineering purposes including plant design, automatic controls and optimization. Accordingly, it behooves the mining companies and plant operators to take advantage of these new developments to control a large number of physical and chemical parameters involved in the plant operation and optimization. This is especially important in light of declining head grades and increasing operating costs in the U.S. minerals industry if it wishes to maintain a competitive edge in the international marketplace. In regard to the future R & D activities in the field, in order to arrive at useful correlations in micro- engineering research, it is essential to consider a plant operation as an interactive engineering system representing the combined effects of physics and chemistry, equipment and operation. The important issues that needs to be addressed in the future are

Jan 1, 1993

By G. B. Walker

The success of Heavy Media Separation, the static sink-float process, is evidenced by the operation of an estimated 300 installations treating many millions of tons per year of a wide variety of mineral products ranging in value from gravel to diamonds. The static heavy media process is usually limited to the treatment of plus 1/4 inch material. Mr. Victor Rakowsky, who was largely instrumental in the development and application of heavy media separation, recognized the need for a new apparatus and process which would extend the application of heavy media into the finer size range without placing a restrictive limit on the top size of the feed. He recognized the requirement for the application of centrifugal force to augment the force of gravity in separating fines by sink-float techniques.

Jan 1, 1966

By James J. Scott

Friction Rock Stabilizers, trade name II Sp 1 it Sets'" have been under research and development by the author and the Ingersoll-Rand Company since February of 1973. The United States Bureau of Mines and the Mines Enforcement and Safety Administration as well as many mining companies have cooperated in field testing the device. Split Set rock anchors are distinctively different from the widely used mechanical rock anchors or fully grouted rock anchors. They control ground movement internally in a manner that allows controlled deformation during the early phase of the ground reaction curve but then, as secondary creep develops, anchorage per unit length increases and they serve to strengthen and stabilize the opening for long periods of time. The history of research and development of the Scott Split Set rock anchor system with accompanying laboratory and field test data is presented in this paper.

Jan 1, 1977

By Rahul Bhaduri

Mercury levels in Twin Creeks Vista pit ore (previously Chimney Creek, North pit ore) increased substantially since plant start-up in November 1987. Consequently, modifications were necessary to minimize industrial hygiene hazards and potential operational problems. The original plant design included mercury control measures. With progressive increases in mercury levels, the issue had to be re-addressed. Modifications to operational practice, industrial hygiene and management philosophy will be discussed. Additionally, a detailed examination of the mercury vapor suppression system currently employed at Twin Creeks will be presented.

Jan 1, 1994

By W. Choi

The present study revealed that the bioleachability of a chalcopyrite flotation concentrate is influenced by the semiconductor properties of CuFeS2. The overall reaction of biooxidation,

Jan 1, 1991

By J. W. Hawley, G. S. Austin, L. A. Brandvold, J. Renault

Soil next to a smelter abandoned about 100 years ago near Socorro, NM was found, by the US Environmental Protection Agency (EPA), to contain high Pb concentrations. Detailed characterization of the soil by the New Mexico Bureau of Mines and Mineral Resources (Bureau) shows that the highest Pb concentration is in the clay-size fraction, although this fraction accounts for only 1 to 3 wt % of the soil. The depth of contamination, determined in areas relatively undisturbed since the smelter was abandoned, is no more than 76 mm (3 in.). Because of the soil's alkalinity, the Pb mobility is dominated by the movement of Pb-bearing particles, as opposed to chemical transport in solution.

Jan 1, 1994

By R. Brantley Sudderth

There are three broad categories in which most solvent extraction technology can be distributed?: 1) reagents, 2) equipment, and 3) systems. Reagents which are now used in commercial solvent extraction plants are of many chemical types, and each possesses certain properties which make it more economically desirable than another alternative. The equipment which is' used in solvent extraction plants for contacting the organic and aqueous phases and separating the same is varied. Most common to the industry is the mixer-settler unit which in itself, can be of varied design; but many new innovations in contacting and separating equipment have been recently introduced or are :now being studied. Each specific solvent extraction application will often dictate the type of contacting and separating equipment used. Obviously, the trend is toward smaller less expensive equipment which reduces the often expensive organic inventories necessary for most solvent extraction plants. The current thrust of .investigations in ancillary equipment is usually aimed at recovering organic from solvent extraction sludges or from aqueous streams exiting the process.6 This type of equipment helps to reduce the total organic losses from solvent extraction plants and thus reduce the operating costs. The term "systems" in solvent extraction applies to the manner in which a solvent extraction process is carried out. This manner is usually dictated by the properties of the reagent which is used, and it involves a tailoring of the equipment or the process flowsheet. Some of the things which can be tailored are: 1) The aqueous media -whether acidic or basic and what type of acid or base 2) Counter-current or single stage (co-current) contacting 3) EMF or pH control 4) Organic "crowding" alternative 5) Heating or cooling process streams Regardless of the type or extent of tailoring, efforts to do this are usually a result of the low cost of solvent extraction as a unit process.

Jan 1, 1977

By X. X. Shao

Dewatering of ultra-fine clean coal slurry to a low moisture level of20 percent is difficult using the conventional techniques. A novel approach, which utilized mixing of fibrous waste material, such as paper, carpet and wood, with coal slurry prior to dewatering was developed. It was found that addition of about 10 Kg/t of carpet fibers or 5 Kg/t of raw paper pulp lowered the filter cake moisture from 22.5 to 18 percent. The compressive strength of the filter cake improved from 0 to 4.5 Kglcm2 and impact resistance from 0 to 4. The experimental data indicated that the handling character of the dewatered fine coal was improved significantly.

Jan 1, 1998

By Andrew Torok

Activated bleaching clays, so called because of their ability to remove color bodies from bleach fats and oils, are produced from clays of bentonitic origin. Activation is achieved by subjecting these clays to physical or chemical alteration to increase selective sorption capacities (1) . The future of activated bleaching clays depends upon the ability of producers to recognize the new areas of applications which are arising, and their skill in developing sophisticated active clays to meet new and stringent requirements. The major portion of activated bentonites are produced for decolorization of oils. New techniques of activation will improve these clays for broader spectrum use. General properties expected to result from present activation methods are: 1. Modification of hydrophobic-hydrophilic properties and increased available surface area in non-aqueous systems, thereby improving sorption capacity and ability to remove color bodies from oils. The following additional properties will be expected from future activated clays: 2. High purity of the active clay with interfering impurities totally removed. 3. Increased selective sorption capacity in aqueous systems. 4. Selective chemical reactivity, such as oxidation or hydrolysis. This property is required for removing

Jan 1, 1971