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By F. T. Davis

Many contributors have added to the fund of knowledge in the basic sciences related to mineral dressing during the past year. During 1964, the French edition of the Proceedings of the VIth International Mineral Processing Congress together with discussions was printed. Also, complete Preprints of papers delivered at the VIIth IMPC were published in September1. Over a third of the papers presented at VIIth IMPC dealt with fundamentals. COMMINUTION It has been postulated by Ponceleta that flaws need not exist before a stress is applied but rather the flaws are created at the tip of a propagating crack at a stress well below the theoretical breaking stress.

Jan 2, 1965

By M. Wrobel, J. Hammerschmidt, M. Runkel

Fluid-bed technology is a key pyrometallurgical step for processing a vast number of ores and concentrates. Over the past 50 years, considerable research and development efforts have been made by Metso Outotec to expand the application window of this technology. This paper illustrates different processing routes where fluid-bed technology plays an important role in the production of the copper. The fluid-bed processes utilized are partial, sulfate-producing, and dead roasting. The focus of this paper considers the advantages of the dead-roasting process. This “zero waste” process can provide copper oxides, steam, electrical power, and sulfuric acid for new and existing solvent extraction–electrowinning plants. In a case where an operation is running out of oxidic ores and concentrates, fluid-bed roasting can be applied to close this gap and provide the required copper oxides in a sustainable way.

Jan 1, 2023

By F. P. Haver

Because of increasing concern with air pollution, the Bureau of Mines has developed a hydrometallurgical procedure to obtain elemental sulfur from chalcopyrite (CuFeS2) by means of the following reaction: CuFeS2 + 3FeCl3 ? CuCl + 4FeCl2 + 2S. Under optimum conditions, 99.6 percent of the copper and 71.6 percent of the iron were extracted in 2 hours from a typical mill concentrate containing 75 percent CuFeS2 and 15 percent pyrite (FeS2). At the same time, 68.2 percent of the sulfur in the concentrate was oxidized to the elemental form. The leach was highly selective; gangue minerals, including pyrite, were not attacked, thus accounting for the relatively low recoveries of iron and sulfur. To obtain these results, the concentrate was ground to 98.9 percent minus 325 mesh, and 300 grams was treated with 1 liter of boiling ferric chloride (FeCl3) solution. The FeC13/CuFeS2 ratio was 2.7. Cement copper containing 99.9 percent copper was recovered from the leach solution by cementation on sponge iron. Excess iron, dissolved during leaching and cementation, was removed from the stripped solution by crystallization. Ferrous chloride (FeCl2?4H2O), obtained as a byproduct, was converted to high-purity ferric oxide (Fe203) and HCI by an oxidizing roast. The hydrochloric acid was then electrolyzed to obtain chlorine, which was used to regenerate the leach solution. The leach residue, which contained ~50 weight-percent elemental sulfur, was treated with an organic solvent to recover the sulfur and cyanided to reclaim gold and silver.

Jan 1, 1971

ST. LOUIS LOCAL SECTION Executive Committee ARTHUR THACHER, Chairman R. A. BULL, Vice-Chairman WALTER E. MCCOURT, Secretary-Treasurer, Washington University, St. Louis, Mo. H. A. BUEHLER R. R.-S. PARSONS HERBERT A. WHEELER On the afternoon of May 1, 1915, 42 members of the St. Louis Section, as the guests of E. S. Catch, President, and his associates in the Granby Mining & Smelting Co., visited the new zinc smelter of that company at Roselake, Ill. The annual meeting, which was preceded by a dinner at the St. Louis Club, was attended by 54 members and guests. The Chairman, H. A. Wheeler, presided. The Chairman rendered a report on the activities of the Section during the past year and the Treasurer presented a financial report. The following Executive Committee was elected: Arthur Thacher, Chairman; R. A. Bull, Vice-Chairman; W. E. McCourt, Secre-tary-Treasurer; H. A. Buehler, R. R.. S.. Parsons. H. A. Wheeler, as retiring Chairman, retains membership in the committee. W. L. Saunders, President of the Institute, made an address. H. W. Gepp, of Australia, described the lead and zinc deposits of Broken Hill, Australia, and V. H. Hughes, of Tulsa, spoke on the geology of the Cushing oil pool, Oklahoma. WALTER E. MCCOURT, Secretary.

Jan 6, 1915

By Zhiyuan Ma, Yong Liu, Xianjin Lyu, Jianfang Lyu, Jikui Zhou

A stable and continuous leaching process for niobium and tantalum extraction from ferrocolumbium tantalum (FT) was developed. The effects of initial concentration of HF and H2SO4, grinding fineness, leaching time, and temperature on the leaching rate of Ta, Nb, Fe, and Si were studied. Experimental results show that the leaching rates of Ta, Nb, Fe, and Si were enhanced by the increase of acid concentrate, fineness, leaching time, and leaching temperature. The optimum process conditions are HF initial concentration of 5 mol/L, H2SO4 initial concentration of 2.5 mol/L, − 74 μm percentage of 65%, leaching time of 20 min, and leaching temperature of 25 °C. Continuous leaching of FT was carried out by feeding ore and acid every 20 min. By leaching with HF − H2SO4 for 4 h, then adding appropriate amount of HNO3 into the solution and keeping for another 1 h, a high Nb extraction rate of 99.8% was achieved. The established method provides a promising technique for the high-efficiency separation of niobium and tantalum from FT.

Jun 5, 2022

By Khandaker M. Anwar Hossain

This paper presents the development of lightweight concrete (LWC) incorporating pumice aggregate and volcanic ash (VA) based ASTM Type I blended cement (PVAC). Fresh and mechanical properties of LWC mixtures such as slump, air content, compressive strength, tensile strength, density and modulus of elasticity are described. The durability characteristics are investigated by drying shrinkage (DS) and water permeability. The investigation suggests the production of LWCs incorporating blended PVAC and VPA having satisfactory strength/durability characteristics for structural applications. The use of PVAC induces the beneficial effect of reducing drying shrinkage and water permeability. Development of such non- expensive and environmentally friendly LWCs with acceptable strength and durability characteristics is extremely helpful for the sustainable development and rehabilitation of volcanic disaster areas around the world.

Jan 1, 2010

By R. Zivojinovic, S. Vujic, T. Tanaskovic

The problem of determining the optimum exploitation life of machinery, namely the optimum time for machinery and equipment replacement, represents a complex and highly responsible engineering task. Taking into consideration the situation prevailing at coal pit mines in Yugoslavia, the tasks of this class are very complex and difficult. To make a decision on replacement of capital equipment and machinery, such as bucket wheel excavators within the mentioned systems, understands a management task of utmost responsibility. It requires high professional and analytical knowledge as well as the reliable arguments, based on multidisciplinary professional approach. In this paper, the authors present their views on the problem of establishing the optimum exploitation life of bucket wheel excavators, offering an algorithm, based on dynamic programming, as a solution. Keywords: Bucket wheel excavators, exploitation life of machinery, optimization, operations research, theory of replacement, dynamic programming

Jan 1, 2003

By Robert L. Hautala

In 1978, Congress established a series of mineral institutes for a limited time to assist financially in mineral industry education and research. Later, education and research were separated, establishing generic institutes for specialized research that transferred the former research budget from the base mineral institutes program. One of the generic institutes is the Mine Systems Design and Ground Control (MSDGC). It provides for research funding specifically for mining. Other parallel generic institutes were established in pyrometallurgy, comminution, waste management, etc. MSDGC was established at Virginia Polytechnic Institute and State University(VPI). The founding group included the University of Alabama, University of Kentucky, University of Nevada Reno, University of Idaho and University of Alaska reporting through VPI to the US Bureau of Mines (USBM) and Congress. Other universities also participated on an ad hoc basis.

Jan 1, 1996

By McHenry Mosier

The application of diamond drills for blast holes is limited to the special Job of extracting floor and stope pillars, and therefore their operation is intermittent. The zinc ore drilled occurs in metamorphosed dolomitic limestone. The mining method is sublevel open-stoping on 200- foot lifts. Ample fresh air is provided by mechanical ventilation. Diamond drilling blast holes began in August 1944. Drills were mount- ed on a 3-inch quarry bar. The contract price for labor for operating equipment owned by the company was $0.23 per foot. The diamond bits were cast-set at the factory in a sintered tungsten matrix. Bit replacement costs were $0.15 to $0.20 per foot drilled. The feet drilled per bit ranged from 87 to 258. The feet drilled per diamond-drill shift ranged from 121 to 129. Holes were loaded with 60-percent special gelatin dyna- mite and fired electrically. In percussion drilling, the estimated feet drilled por machine shift with hand-held sinkers was 65. The tons broken per machine shift averaged 40 throughout the mine. Detachable bits have been adopted recently. The principal advantage of diamond-drilling blast holes at the Balmat mino is the extraction in a safe manner of ore not minable by short-hole drilling. The principal disadvantago is the greater cost per foot of holo in comparison with percussion drilling.

Jun 1, 1947

By Shosei Serata

Serious floor heave of up to 2.4 m in a 2.4-m high mine entry was eliminated by applying the stress control method of mining, as a last resort, at the No. 5 coal mine of Jim Walter Resources, Inc., in the Black Warrior coal basin near Birmingham. Alabama. Underground observation of the first 3-room entry created using the stress control method is discussed here. The behavior of the test entry, which eliminated the heave problem, is analyzed in relation to similar studies conducted in a salt mine under similar ground conditions by utilizing finite element analysis.

Jan 1, 1984

By A. L. de Vegt

Hydrogen sulfide is an expensive chemical used in nickel, zinc and copper mining and metallurgical operations for selective recovery and concentration of metals from leach water streams, acid plant blow down streams, refinery electrolyte bleeds and precious metal plant bleeds. Hydrogen sulfide is either produced on site by catalytic reduction of elemental sulfur or transported to the site as liquefied hydrogen sulfide (H2S) or as a sodium sulfide solution (NaHS). Biologically produced hydrogen sulfide has economically very interesting application possibilities in the mining and metallurgical industry. Converting sulfates from waste streams into usable hydrogen sulfide by biological reduction results in operational cost savings in existing lime treatment systems. H2S can be produced biologically for less than $500/ton S. For the past ten years Paques has been engaged in the development and installation of treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. Paques has designed and installed a groundwater treatment system for the Budelco zinc refinery in the Netherlands to remove sulfate and heavy metals. The hydrogen sulfide produced is used for recovery of metals, mainly zinc, from the ground water stream. The system has been operating since May 1992 treating a flow of 5000 m3/d. At Kennecott's Bingham Canyon Utah copper mine a pilot plant started operation in November 1995 to develop the process for selective recovery of copper from leach water using biologically produced hydrogen sulfide from sulfate containing groundwater. Other pilot plants are operated at DOE's Pittsburgh Research Center and at Cominco Research focusing on selective recovery of metals.

Jan 1, 1998

An Application of Depressant BK510 in Separation of Molybdenite and Bismuth by Flotation

Sep 13, 2010

By Thomas L. Mell

Continuous processing plants handling liquids have achieved a high degree of centralized automatic control. Many chemical plants are operated from one room, with automatic control of the various process flow rates. These plants know from experience that automatic control can produce higher through-put, better uniformity of product, decreased operating costs and reduction of storage capacity, Plants which process materials in the form of bulk solids have not been able to use control to as great an extent, primarily due to the lack of measuring equipment capable of providing the same types of continuous automatic control available with liquid flow meters. This paper will describe a scale for measuring flows of bulk materials on conveyor belts which is particularly adaptable to remote centralized instrumentation and automatic control, and will also describe some typical control applications. Fig. 1 illustrates the basic method of measurement of this scale. A conveyor belt idler is supported on a rigid carriage which in turn is mounted in two anti- friction bearings on the conveyor stringers. The pivoted carriage is prevented from rotating about the pivot shaft by an electric strain gauge load cell connected between the carriage and a cross support. Increasing load on the conveyor belt increases the moment of the carriage frame about the pivot shaft, and proportionally increases the tension in the load cell. The belt speed is measured by a conventional d. c. tachometer generator driven from a pulley, usually on the return belt. The speed signal from the tachometer generator and the load signal from the load cell are combined to produce a signal proportional to the flow rate of material in tons per hour, or lbs. per foot, or equivalent units, It will be important to remember, in considering various control applications, that the flow rate of material on the belt is composed of these two component signals, namely the weight of material and the speed at which it is moving. The feed rate is then indicated and recorded by a self-balancing potentiometer of the type used for measuring temperature by means of thermocouples. These instruments may also be equipped with integrating mechanisms reading the totalized tonnage over a period of time.

Jan 1, 1958

By J. A. Drozdiak, W. Tse, P. P. Rosario

"In a recent publication (SAG 2015), we presented a non-conventional high pressure grinding roll (HPGR)-ball mill circuit as a lower capital cost alternative to the “standard” HPGR circuit. The circuit was designed for the treatment of a hard ore and relatively high tonnage (50,000 t/d). That paper provided details such as flowsheets, layouts, and equipment lists for the two options and compared their calculated capital costs demonstrating significant savings for the proposed circuit. This paper extends the analysis to a third option, a traditional semi-autogenous ball crushing circuit, giving the same level of details and now including the operating cost estimates for all three options for a more comprehensive analysis. Moreover, this work also provides information about the strengths and weaknesses of the non-conventional HPGR circuit when compared to the “standard” HPGR option.This study demonstrates that the proposed non-conventional HPGR-based circuit not only provides a lower overall capital costs for the project if compared to a “standard” HPGR circuit but also brings the capital cost to the level of the traditional semi-autogenous grinding (SAG)-ball mill circuits. In addition, the innovative HPGR circuit provides similar operational cost savings of the “standard” HPGR and thus a significant advantage when compared to the SAG option. With the current capital cost sensitivity for most greenfield projects, the proposed alternative circuit should help make HPGR-based circuits more competitive and thus promote the utilization of a technology that enables higher energy efficiency and reduced greenhouse gas emissions. INTRODUCTIONThe application of high pressure grinding roll (HPGR) technology in comminution circuits is well established for the processing of cement, diamonds and iron ore (Broeckmann & Gardula, 2005), and over the past 10–15 years, this technology has slowly been applied to hard ores in high-tonnage precious and base metal operations. Unfortunately, under the current economic climate, the ability to finance large capital projects has become very difficult and companies tend to have an easier time securing funding if the capital expenditures (CAPEX) are low with a proven process method. The traditional semi-autogenous grinding (SAG) mill / ball mill circuits easily fit into this mould, having been installed in countless plants around the world over the past 30 years with relatively low capital requirements. In contrast, it has been well-documented that HPGR-based circuits are capital intensive with complex material handling systems (Seidel, Logan, LeVier, & Veillette, 2006). Although these circuits benefit from reduced operating costs with the increase in energy efficiency and the elimination of steel grinding media (Rosario, Boyd, & Grundy, 2009), if the company is unable to secure financing to build the plant, these advantages remain out of reach. With the current trend to retrofit existing SAG circuits with a secondary crushing circuit to achieve design throughput, the opportunity to circumvent this gross inefficiency by making HPGR-based circuits more capital friendly would greatly benefit the industry."

Jan 1, 2016

By P. Coulombe, J-F. Riverin, A. Gaboury

Cavity cleaning during anode change generates a material that consists of anode cover material and cryolite melts. This material is scooped and placed in bins for transport and further processing and recycling as fresh anode cover material. Typical processing methods in use involve cooling of the hot cavity bath in bins, with or without emission treatment systems, until it is adequate to be processed and grinded to the required particle size distribution. Handling of the hot and cooled cavity bath material can be labour intensive. It also generates significant air emissions which contain particulate and gaseous fluorides. With the advent of the Aluminerie Alouette smelter Phase II expansion, the hot cavity bath tonnage to be processed increased to 700 t/day and maintaining existing practices was not satisfactory. This article presents a novel process implemented at the Alouette smelter where cavity bath is processed as a hot material directly from the potlines ( 600-800°C range), sized, cooled and then processed in the existing cold bath treatment plant. The system is designed to process 36 t/h, is fully automated and requires limited monitoring from operations. Implementing this new system in a Browrifield environment imposed numerous constraints for space, interfaces with existing operations, commissioning and ramp-up. It is presently operating at approximately 80% availability and is easily meeting the requirements of the potlines. This system has significantly improved the workplace environment in the bath treatment area and reduced the overall particulate and gaseous fluorides emissions at Alouette. Aluminium 2006 45th Annual Conference of Metallurgists ofCIM Montreal, Quebec, Canada Edited by

Jan 1, 2006

By Simon St J Tose

The objective of this paper and presentation is to review the different criteria and methodology used by AEL and other organisations to create a pre-split design which delivers a stable highwall for the life of that part of the mining operation. It will look at the need to adapt and change the way, size and direction of the production blasts as the mining phase approaches the highwall position for which a pre-split has been created. Key Words: Pre-split: Design; Highwall; Perimeter

Jan 1, 2006

By Venda Oliveira P. J., Correia A. A. S., Danisi C. M.

"AbstractA laboratory study has been undertaken to establish common understanding of the creep phenomenon of a Portuguese soft soil chemically stabilised with binders. In order to study the effect of different stress levels on the strength and on the creep behavior of the stabilised soil, oedometer creep tests and unconfined compressive tests were performed at different curing times. Results show that the creep stress level does not influence the unconfined compressive strength. In addition, the creep phenomenon increases the unconfined compressive strength of the treated soil. Two different secondary compression indexes were recognized from the one-dimensional compression curve which increase with an exponential trend with the creep stress level.IntroductionConstruction on soft soils requires a mandatory soil stabilization work to improve mechanical characteristics of the natural soil. Deep mixing method is a worldwide employed ground improvement method, nevertheless the creep phenomenon hasn’t been yet thoroughly analyzed. Most of the published papers have focused on the analysis of the compressibility and the strength of the soil-binder mixtures without considering the creep phenomenon. However, numerical results (Venda Oliveira et al. 2009) have shown that although settlements that occur during the creep stage (namely creep strains) are less in case of treated columns, they are still important especially due to the high loads applied to the stabilised soil. The few published studies about creep behavior of soil-binder mixtures reveal that the stabilization of an organic soil with cement induces a reduction of creep deformations, which is related to the amount of cement used and that the increase of the organic matter of the soil has a negative impact on soil stabilization, further inducing a slight increase in the creep deformations (Venda Oliveira et al. 2012).As part of the current research the effect of different stress levels on the creep behavior of a soft clayey-silt soil was studied. The binder mixture used to enhance the properties of the soil had a specific composition and quantity. Unconfined compressive strength tests (UCS) and UCS creep tests were carried out at pre-set curing times in order to analyze the creep behavior of the soil-binder mixture. In particular five different creep stress levels were studied to understand its influence on the strength and on the compressibility of the stabilised soil. In addition, considerations about the secondary consolidation index are also presented."

Jan 1, 2014

By J. A. Mielczarski

Surface properties of minerals could be modified selectively and very specifically by adsorption -desorption (dissolution) processes. This requires a monitoring and control of the outermost surface layer at a molecular and atomic level. The nature and structure of self-assembled submonolayers and monolayers at the interface of minerals were studied by infrared reflection spectroscopy. The external reflection spectra of the adsorbed monolayers on any type of minerals: transparent, opaque or non-transparent, recorded at different angles of incidence and for two polarizations are an excellent source of information about the nature and surface distribution of the adsorbed species. The developed method allows to obtain detailed information at a molecular level about the adsorbed surface species. By combination of the simulated and experimental data, the qualitative description of the adsorbed species as well as quantitative evaluation of orientation and the thickness of the adsorption layers were obtained. This fundamental knowledge allows to determine the mechanisms of surface phenomena which govern selective separations. Examples of different surfactant - mineral systems and industrial applications will be discussed.

Jan 1, 2000

By Michael Peterson, Robert Davinroy, Robert Rapp, Gregory Hempen, David Herzog, Thomas Keevin

Fish sampling in a deep-water, high velocity, environment is extremely difficult. Conventional techniques such as electro-fishing and netting have been limited to depths generally less than 7 meters (m) and velocities below 1 meter per second (mps). The goal of our study was to sample a bendway weir field on the Mississippi River to assess the effects of the weir field on the fishery. In a bendway weir field, depths can exceed 20 m, and velocities can exceed 3 mps, making conventional sampling techniques inefficient.

Jan 1, 2002

By Paul D. Tomlingson

There are huge benefits for mining operations that have a well-defined maintenance program that is understood and followed across the total operation. But for operations lacking a quality maintenance program, there is equal assurance that nearly every major maintenance problem can be traced to this omission. Few problems will be permanently corrected until such a program is implemented. Definition The maintenance program re-quires the interaction of all mine departments. Initially, the production department will request work and the maintenance department will identify work, principally through preventive maintenance inspection and testing efforts. Maintenance will then classify the new work to determine the best way to respond. Maintenance will plan selected major jobs to enable its crews to carry them out more effectively. Maintenance will schedule the planned work with operations. Supervisors will assign all types of work to their crews then, control the work through effective supervision. As work is completed, maintenance will measure the work using an accurate information system. Next, it will assess overall accomplishments against goals such as performance standards or budgets. In addition, the pro-gram would prescribe a means to evaluate every aspect of the operation as it affects maintenance so that necessary improvements or changes can be identified, prioritized and acted on. Such evaluations should be part of a mine-wide continuous improvement effort. A well-defined maintenance program is one of the best investments a mining operation can make to assure its profitability. Educating the total operation on the pro-gram assures long-term dividends from the investment.

Jan 1, 2008