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By George A. Desborough, Stephen J. Sutley, Reinhard W. Leinz, Paul H. Briggs

The mode of occurrence of metals in mine wastes is investigated using sequential extractions. Metals are extracted from some or all of seven operationally-defined phases: water-soluble, ion-exchangeable, carbonate, amorphous Fe-oxide, crystalline Fe-oxide, sulfide, and silicate. The quantity of metals extracted from each phase varies with particle size. The presence of jarosite (potassium end-member formula, KFe3[SO4]2[OH]6) influences the selection of the procedure for extracting the crystalline Fe-oxide phase. Anglesite (PbSO4) and cerussite (PbCO3) are extracted as several phases. Extraction results can be explained only in part by X-ray diffraction (XRD) mineralogy because of lack of specificity of the extraction procedures, relatively high XRD detection limits, and the presence of 40% XRD-amorphous matter in each waste. The increasing chemical strength of the sequentially applied methods provides a basis for judging metal availability, water-soluble metals being most available and silicate-bound metals being least available.

Jan 1, 2000

My "outside exploration" began in November 1908, only 16 months after I had come to Bisbee as a raw engineer. The well publicized reputations of eminent engineers up to that time, including John Hayes Hammond, Herbert Hoover, James Douglas, D.C. Jack- ling, J. Park Channing, and a few others had been due to new mines they had found or brought to successful operation. And here was I, a mere youngster, given a chance to join the group. I knew there would be disappointments but I had no idea how many of them. In spite of the many prospects that turned out to be worthless I never looked at a new one without the feeling that this one might turn out to be the big success. This confidence, blind as it was, gave every arduous examination a zest and it made me climb every mountain on which the owner said there was something worth seeing, or on which T could see a distant staining that might mean ore. If I looked at every showing the owner suggested he at least would think I was honest and would bring other properties to our attention. This reputation of never refusing to go to see an outcrop, no matter how hot the desert sun or how rough the terrain, was probably one of my best assets. High as my hopes were at the start, they proved not to be exaggerated and if I were given a chance to do it again I would not hesitate, in spite of the jaundice, rheumatic fever, and other maladies that beset some of the expeditions. On the whole the results have equaled all my hopes. Toward the end of my years of active exploration I totaled up the score. Out of the prospects submitted to us about two out of three were eliminated after questioning the owner or prospector, without an examination. This left about a 1000 mines or prospects that seemed worth at least a preliminary look. One out of seven of these was worth a little development and a seventh of this seventh turned out to be a modest success or better. And nine or ten in all, or one out of 1000

Jan 1, 1976

By Carlos Kovacs-Figueroa

Because of air pollution control regulations in the early 701s it became necessary to clean effluent gases from the Morenci Reduction Works Smelter. Feasibility studies indicated that this could be accomplished most efficiently by using the smelter gaseous effluent to feed a sulfuric acid plant. Complying with air pollution control regulations thus created the need to dispose of relatively large amounts of concentrated sulfuric acid. Typical Morenci ores contain substantial amounts of oxidized copper minerals which are not recoverable by flotation. In addition, there is low sulfide, high oxide material which can be leached, but is not suitable for flotation concentration. Early in 1971 sufficent data had been accumulated to show that a leaching plant for the Morenci tailings could use a large portion of the sulfuric acid produced by the Smelter. It was determined that for all practical purposes leaching of the available copper was complete in two hours or less. Capital expenditures could not be justified for more than two stages of counter current decantation for recovery of the leached copper, and the plant was designed with these criteria in mind.

Jan 1, 1976

By D. P. Patil, B. K. Parekh

Water is the mainstay for beneficiation of fine size coal and minerals; however, it is also the least desirable constituent in the final product. The basic concept of the novel process described in this paper is based on the differential surface heat absorption capacity of individual particles, which differs for different species of mineral. When a mixture of fine material is exposed to a radiant energy source, the various solids components present in the mixture will absorb heat energy depending on their composition and there will be difference in the surface temperature of the particles. When this differentially heated solid mixture is placed on a moving belt, which is coated with low temperature melting resin, the hotter component of the mixture will stick to the belt and relatively cooler will stay free on the belt and fall off at the end of the belt run. Experiments were conducted with pyrite, coal and quartz of 6 x18 mesh particle size. The goal of the test program was to find the optimum conditions at which there exists a required temperature difference between minerals and coal particles by controlling the operating and system variables. Preliminary tests results showed that there is a potential for separating mineral matter from coal using the thermo-adhesive separation technique.

Mar 2, 2022

By J. G. Groppo

Eastern U.S. oil shale contains approximately 10 to 12 gallons of oil per ton and 7 to 10 percent pyritic sulfur. Physical beneficiation of these low grade shales using froth flotation provides a high grade material which will make extraction of oil more economically attractive. The Alabama oil shale used in the present study contained 16.46 percent organic carbon and 14.5 gallons of oil per ton as determined by Fischer assay. Liberation size of the kerogen was estimated at 10 /-Lm. 'Ken-Flote' column flotation technology provided a high grade concentrate containing as much as 60 percent organic carbon, however, carbon recovery was about 60 percent. Carbon recovery was improved to 75-85 percent while maintaining concentrate grades in excess of 40 percent carbon by providing longer retention time in the column which facilitated effective bubble-particle collision and attachment.

Jan 1, 1993

By A. Arik

1his paper presents a modified ordinary kriging technique referred to as the "Nearest Neighbor Kriging" (NNK). The method is a simple and practical tool to use when the ordinary kriging (OK) results are unreasonably smooth, especially when estimating recoverable ore reserves for deposits with skewed grade distributions. NNK is robust and globally unbiased like OK. However, it is more advantageous over OK because it can control some of the smoothing and conditional bias which have been the major pitfalls of OK in many grade estimation cases. The paper details the methodology of NNK and its application to a gold deposit.

Jan 1, 1998

By D. Gove

All mining operations using trucks have a common need to properly match the number and size of hauling units (trucks. wagons. scrapers. etc.) to a loading unit (wheel loader. hydraulic shovel/excavator, cable shovel. push tractor. etc.) to provide the best possible fleet match. Optimizing fleet match minimizes the cost per unit of material moved by that fleet. As haul conditions change (haul length. grade. or rolling resistance), there may be need to adjust the number of trucks to maintain the optimum fleet match. Fleet Production and Cost is a tool which, among other things, can be used to optimize the truck-loader match.

Jan 1, 1994

By D. A. Norrgran

The recent development of rare earth permanent magnets has revolutionized the field of magnetic separation. The advent of rare earth permanent magnets in the 1980's provided a magnetic energy product an order of magnitude greater than that of conventional ferrite magnets. This has allowed the design of high-intensity magnetic circuits operating energy free and surpassing the strength and effectiveness of electromagnets. New applications and design concepts focused on the mineral and metal processing industries have evolved. This technology also led to the development of various magnetic separators specifically designed for mineral processing applications. Applications which were not previously considered are now being applied to primary mineral upgrading and recycling and secondary recovery.

Jan 1, 1993

By S. G. Malghan

This paper describes uses of sodium sulfide in the flotation of oxide and sulfide minerals of copper, lead, and zinc. The activation and depression effects of sodium sulfide are of particular importance because of their applications with oxidized lead and copper ores. In spite of its industrial importance; however, the nature of the heterogenious reactions between sulfide ions in solution and the surface of oxidized minerals has not been fully understood. Hence, proposed mechanisms of the sulfide action in flotation, methods of measuring and monitoring of sodium sulfide in flotation pulps, and variables influencing the sulfide addition are analyzed. A review of recent studies shows that sodium sulfide addition to flotation pulps can be monitored and hence the optimum dosage controlled using the platinum and/or sulfide specific ion electrodes. The use of these electrodes for improved reproducibility of bench-scale experimental data and plant implementation of laboratory results is described.

Jan 1, 1985

By J. D. Isbister

Coal is the most abundant and most economical source of energy in the United States, however, combustion of coal results in release of pollutants to the environment. The release of sulfur dioxide and oxides of nitrogen during combustion of coal contributes to the deterioration of the environment. Energy independence in the United States must include the increased use of coal reserves. Increased reliance on coal for energy will dictate the necessity for making coal a cleaner fuel. New technologies employing a variety of techniques from harsh chemical treatment to mild physical separations to clean coal are rapidly becoming available. Success for any coal cleaning process is in economics which translate into efficient removal of sulfur with high recovery of combustibles as well as low capital and operating costs for the process. Conventional coal cleaning processes remove water soluble sulfates and a portion of the pyritic sulfur and ash from coals. Removal of additional sulfur from coals requires more advanced coal cleaning techniques. Coal contains many organic sulfur forms which are the most difficult of the sulfur types to remove from coal. The heteroaromatic sulfur species, such as the comlex thiophenes, are the most commonly found organic sulfur forms. These sulfur forms are resistant to chemical attack and are considered to be refractory compounds. Atlantic Research Corporation has developed an "unique" microorganism, CB1 (Coal Bug 1), capable of oxidizing thiophenic sulfur in coal to form water soluble sulfates.

Jan 1, 1986

By Paul C. Schmall, John F. Donohoe, Arthur B. Corwin

In the aftermath of the September 11th attack on the World Trade Center, groundwater control was of immediate concern. Water in?ow from the adjacent Hudson River through the compromised slurry wall ‘bathtub’ surrounding the site, ruptured water and sewer mains, and saturation from fire hoses all contributed to an already critical situation, further hampering the recovery and rehabilitation effort. An extensive pumping and deep well installation program was initiated, focused on reducing the hydrostatic loading to the severely damaged perimeter slurry wall.

Jan 1, 2003

By T. Umadevi, A. Pratap Singh, R. Sah, K. Abhishek

"It was possible to beneficiate a low-grade iron ore fines sample from Bellary-Hospet, Karnataka, India assaying 56% Fe, 9.1% SiO2 and 5.2% Al2O3 and produce two concentrates, namely, a sinter-grade fines concentrate (43.7% by weight), assaying 63.6% Fe, 2.6% SiO2 and 1.7% Al2O3, and a pellet-grade concentrate (30.7% by weight) assaying 64.7% Fe, 2.9% SiO2 and 1.7%Al2O3. Rejects (25.6% by weight) assayed 32.5% Fe, 27.9% SiO2 and 15.4% Al2O3. The mineralogical characterization indicated that the sample consisted of 69.5% ironbearing minerals (56% hematite, 7.5% martite and 6% goethite-limonite), 12.5% quartz and 15.2% clay, and the rest were minor minerals. Liberation size was found to be in the size range of 25 to 100 µm. The process flow sheet consists of jigs, spirals, grinding and low- and high-intensity magnetic separation of the deslimed feed. IntroductionJSW Steel Ltd is a 10-Mt/a integrated steel plant. To produce 10 Mt/a hot metal requires nearly 16 to 20 Mt/a iron ore fines. The fast depletion of highgrade iron ore fines, increased industrial demand and an increase in iron ore prices have necessitated the exploitation and use of low-grade iron ore fines in the steel-making process after beneficiation. Thus, the beneficiation of low-grade iron ores by removing the associated gangue minerals and enhancing their grade is essential. The use of these iron ore fines in sinter and pellet making has prompted the undertaking of systematic studies on low-grade iron ores.Finely disseminated low-grade iron ores with siliceous impurities have been upgraded by gravity, magnetic and flotation-based processes (Burt, 1994; Svoboda, 1987; Houot, 1983). The processing of low-grade Indian hematite ore containing high levels of alumina-bearing minerals as impurities present separation challenges and pose special problems in martite and magnetite, in association with quartz and clay as the gangue-forming minerals. Alumina is mainly contributed by clay (kaolinite, montmorillonite, illite, alunite), lateritic material and gibbsite; some alumina occurs as solids in iron oxide minerals, namely, goethite and limonite. Silica is mainly contributed by quartz and the associated clay. achieving a high-grade concentrate (Pradip, 1994; Singh and Mehrotra, 2007). Hematite ore basically consists of varying amounts of hematite, goethite,"

Jan 1, 2015

By N. Kuroda

A realistic simulation model has been used for designing longwall mining, especially for solving operational problems. This paper describes background, development, validation and some applications of the simulation model for mining people who are unfamiliar with O.R. or computer technique, as a simple planning tool. The following items were established: logical analysis and algorithmic design for practical longwall mining, structure of hypothesis behavioral organism, input parameters, using practical knowledge and operational statistics of the mechanized longwall system experienced for many years.

Jan 1, 1982

By Jaeheon Lee, Junmo Ahn, Jiajia Wu

To reduce the environmental footprint of hydrometallurgical processing of black mass from spent lithium-ion batteries (LIBs), a green leaching system based on glycine and sodium metabisulfite (Gly-SMS) was proposed. The leaching study demonstrated that the highest cobalt and lithium recoveries of 100 percent and 99.8 percent were achieved under optimal conditions. The leaching mechanism revealed that the dissolution of LiCoO2 in the Gly-SMS solution followed the shrinking core model. The apparent activation energies for cobalt and lithium were determined as 48.05 and 41.51 kJ/mol, respectively, indicating a surface chemical reaction controlling mechanism. The leachate was then processed by an acidification- precipitation technique with oxalic acid as the precipitant to remove cobalt. Glycine complexes with metal ions by zwitterionic ligand and recycles in the leaching-precipitation circuit, reducing the reagent cost. Compared to other studies, this leaching system has near-neutral operating conditions and is cost-effective, making it an economically viable alternative for treating cathode materials from spent LIBs.

Dec 1, 2024

By Andrew B. Cecala, Robert J. Timko, Christopher J. Pritchard

As mine venti1ation systems become more complex, it is increasingly difficult to supply fresh air to the working face. A high percentage of the fresh air entering a mine never reaches the working face because it short circuits through stoppings and doors, exiting the mine without being utilized. When ventilation limits are reached, the only option presently available to most U.S. mines is to sink a new shaft - an extremely expensive undertaking that many companies cannot afford. Reusing or recirculating a percentage of ventilating airflow may make it possible for some mines to remain operational while maintaining a safe environment for workers. Such a study was performed at a trona mine in Granger. Wyoming. A vane axial fan was used to recirculate approximately 9.4 m /s (20,000 cfm), 25% of the total ventilating airflow, back to the working face area of a three-entry continuous miner section. This study involved two evaluations: the first when the face was 305m (1,000 ft) from the recirculation fan, the second when the face was 610m (2,000 ft) from the fan. The evaluation consisted of monitoring the mine atmosphere for respirable dust, methane (CH4). carbon monoxide (CO), and nitric oxide (NO), at various locations in the intake and return entries. Several shifts were monitored, with and without the recirculation system in operation. With the recirculation system in operation. there was an increase in measured respirable dust concentrations in the intake along with a slight increase in the mine temperature (1.67°C). There were also some minor changes in CO and NO levels in the intake entry, but this seemed to depend on the proximity of the instruments to the turn-around point for the diesel haulage vehicles, than to whether the recirculation system was or was not in use.

Jan 1, 1989

By R. J. Roman

Controlled and uniform distribution of the leach solution to a heap is of primary importance to achieving the desired rate of metal recovery and PLS grade from the heap. The step used to engineer the irrigation system are the same whether drips, wobblers or sprinklers are to be used. The mining rate, leach cycle time and heap height influence the heap cell size which along with the irrigation method selected controls the design of the irrigation system. The steps in the design procedure are explained as are the advantages and disadvantages of each irrigation method.

Jan 1, 1996

By E. Woodburn, Harrison R. Cooper, R. Putman

The key to concentrator automation is practical means for obtaining continuous assay data from concentrator streams. The technique most successfully used is x-ray fluorescence analysis. The practical reality of on-stream x-ray analysis has been achieved through effort over the past twenty years, marked by an occasional breakthrough, but more typically a step-by-step development to which many individuals and organizations have contributed. The net result of this progress is the present capability to install on-stream x-ray analyzer systems on a turn-key basis. It is now possible to provide all components of an x-ray analysis system as a completely engineered unit which can be put into immediate use, minimizing needs for specialized application know- ledge to benefit from continuous assaying in process control. The economic factors which influence the choice of system and limitations of the x-ray fluorescence technique for slurry analysis are reviewed.

Jan 1, 1976

By John B. Rigg

The title of my paper today is "public relations challenges for the pending minerals crunch". There isn't anyone in this room who would dispute. That the minerals industry has always had public relations challenges . . . No matter what the circumstances, mineral shortage or abundance. The industry suffers from an image that is second to none in longevity. It defies all actuarial formulas of the past or the future. Never mind that such an image is outdated, distorted, overstated, and reiterated. I submit that the minerals industry had public relations challenges long before there was anything called public relations. This account of egyptian mining practices, recorded for posterity by Diodorus Suculus at the end of the second century, b.c., is indicative. "On the confines of Egypt . . . And Ethiopia is a place which has many great mines of gold, where the gold is got together with much suffering and expense. The kings of Egypt collect together and consign to the gold-mines those who have been combined for crime, and who have been made captive in way . . . Sometimes only themselves, but sometimes likewise their kindred. "Those who have been consigned to the mines, being maw in number and bound with fetters, toil their tasks continuously both by day and all night long, getting no rest and jealously kept from all escape.

Jan 1, 1975

By Pierre J. Wauters, Eddy J. Jacques

Starting up a fan or modifying its setting point either by rotational speed variations or blade angle changes, obviously results in new ventilation conditions in the network, which is, of course, the object of the operation. However, since transient phenomena may then occur, particularly in complex networks, there may be a need to simulate these situations prior to any action. This is all the more true, if we are dealing with a multiple interactive fan sys- tem. Simulations with a transient model have shown that the flow in certain airways could be temporarily reversed due to the pres- sure variations that reach both its ends with a different time lag. This phenomenon may cause dangerous situations to occur in cases of fire or outburst of methane. It is also true that the air flow could be reversed in secondary and less powerful fans, while still rotating in the normal direction. The study and the experimental investigation of the extension of the reverse flow characteristic is therefore justified from two points of view : • a numerical simulation model for transient flow conditions must be capable of handling temporary reversed flows, and thus have appropriate fan characteristic curves available over the entire operating domain; • while operating fans, reversed flows should be avoided or at least reduced. Therefore, the design of start-up procedures or real time control algorithms should take these phenomena into account. A particular interesting application is the operating of two fans in parallel. In order to investigate experimentally the characteristic curves of a fan under reversed flow conditions a small scale model was built. This facility was designed in such a manner that it was possible to carry out experiments concerning flow reversions and to try out sequential start-up procedures for two fans in parallel.

Jan 1, 1997

By J. E. Carr

A bewildering number of continuous thickeners and clarifiers are used in mineral industries and other heavy industries. General types are: 1. Conventional Thickeners (Fig. 1). 2. Thickeners with Flocculating Feedwells (Fig. 2). 3. Solids Contactors (Fig. 2). 4. Tray Thickeners (Fig. 3). 5. Lamellas (Fig. 4). 6. Conventional Thickeners with Lamellas 7. High Flow, Fluid Bed Thickeners (Fig. 5). These units must be adapted to varied applications. They must provide operating flexibility to meet process needs. Such factors multiply the decisions which must be made prior to the selection of a thickener. The seven types of thickeners listed above, with their variations, share design concepts which limit their application and which can be used to evaluate their performance. Some of these are listed: 1. Feed velocities must be limited and/or controlled. 2. Natural or reagent flocculation is necessary. 3. Horizontal settling area is the basis for capacity. 4. Overflow velocities must be limited and/or controlled. 5. A controlled underflow is necessary. Applying these needs to the basic process concepts is thickener selection. The basic function of a thickener in the minerals industry is the separation of a thickened sludge containing fine solids from water. To this primary separation function are frequently added others to give a list as follows:

Jan 1, 1977