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By Neil H. Bostick

This research, sponsored at Stanford Research Institute by the Grand Junction Operations Office of the U.S, Atomic Energy Commission, was an outgrowth of the concern that presently-known ore reserves may be inadequate to meet the projected demands of nuclear power reactors. The original program at SRI was to design a comprehensive geological information system and use it to store and analyze the very great quantity of data needed to estimate uranium ore reserves. Study of the problem showed that it could be solved only by use of modern electronic data processing techniques, so such a comprehensive system was designed and tested. The system test was satisfactory, but input lead time and total expense were shown to be too great for the system to be practicable for the AEC under present circumstances. Thus, based on results of the earlier research, a specialized and simplified procedure for predicting approximate uranium ore reserves was devised. The prediction is based on general geology of specific area cells of the earth, in order to provide complete volume coverage; the strata in these ores are evaluated for uranium ore favorability on the basis of a few selected criteria in order to allow rapid data input. Since the bulk of U.S. reserves are in clastic host rocks only such strata are considered in this work. This paper describes the structure and some details of the resource system and how it was tested in rn area of the western United States.

Jan 1, 1969

By William Wraith

The availability of computer resources and data management technology, together with the prudent use of scientific management concepts, has made it possible to achieve important improvements in the control of maintenance and materials activities in the mining and minerals processing organization. The introduction of minicomputers and. the greatly improved efficiency of computer systems in general have put the use of computer technology within the reach of even the smaller mining companies which probably could not have afforded them just five to ten years ago. A number of progressive companies have implemented computer-based maintenance, purchasing, and supply inventory control systems. Using modern safety stock, demand forecasting, parts reliability analysis, and other control concepts, these new systems have helped minimize production losses by reducing the frequency and severity of supply shortages and unplanned repairs. At the same time, these systems are helping to conserve scarce capital resources by better utilization of supply inventory investments, reduced expenditures for maintenance, less frequent equipment replacements due to improved maintenance reliability, and greater capacity utilization of existing facilities.

Jan 1, 1979

By P. G. Semple, K. W. Major, R. M. Nendick

As free milling oxide gold ore reserves are depleted, more mining companies are having to evaluate the available alternatives for treating refractory deposits. The selection of a treatment process can be very difficult; and, despite the claims of their respective proponents, there is no one process that will continuously prove superior. Selection of the optimum process for an individual deposit is contingent on the size of the deposit, the grade of the deposit and the refractory nature of the ore. Since extensive metallurgical test programs are usually required to determine the optimum extraction process, an inappropriate initial selection may prove costly and time consuming. This paper discusses the steps involved in evaluating a refractory ore in order to expedite the evaluation of the required process through the feasibility study stage.

Jan 1, 1990

By Otis M. Clarke

Although most bauxite mined is used to make metallic alu¬minum, more than a million tons of bauxite is used annually in the United States in the manufacture of refractories, chemicals, abrasives, and cement. Raw material requirements are becoming increasingly difficult to meet because high-grade bauxite, required for some uses, is limited. The supply of raw material for high-alumina refractories is most critical because a low-iron bauxite is needed. Although there are substantial bauxite reserves in the world, bauxite suitable for use in refractories is limited to a few districts.

Jan 1, 1977

By Robert A. Cummings

A field inventory was made of the mineral, geologic, geothermal, and groundwater resources of three geologically recent lava fields in the desert of Oregon. The term "resource" was applied with care: a "resource" must have particular value or worth, although it need not be economically viable. The spectacular volcanic features of the area have particular scientific and general interest and thus constitute geologic resources. The mineral endowment, mostly occurrences of low unit value such as stone and cinders, in large part are not resources, due to market conditions, regulations, and other factors. These and other conclusions will be used by the Bureau of Land Management in its multiple land use planning process for the area.

Jan 1, 1980

By Yosry A. Attia

One of the most significant advances in Mineral Processing in recent years, is the development of the selective flocculation technology. The technology is primarily aimed at recovering the mineral values from ultrafine ore suspensions. This is achieved by selectively aggregating the mineral particles in question to such size as to enable their effective separation from the suspension. Selective flocculation utilizes the differences in the physical-chemical properties of the various mineral components in the mixed suspension. It is based on the preferential ad- sorption of an organic flocculant on the particular solids to be flocculated, leaving the remainder of the particles in suspension. In order to understand the mechanics of this process, selective flocculation may be divided into four major sub processes; these being: ore slurry dispersion, in which all the particles are stably and uniformly distributed in the suspension with the individual particles being essentially separate; flocculant selective adsorption and floc formation; floc conditioning, which aims at obtaining flocs with desire properties for their subsequent separation and with minimum entrapment of dispersed particles; and floc separation from the suspension. These sub processes will be reviewed later in this article.

Jan 1, 1982

By L. R. Freitas, A. K. Resende, J. A. Oliveria, K. L. Gonçalves, L. F. D’Assumpção, L. R. Lage, J. D. Neto, F. Viveiros

Pará Pigmentos S.A. (PPSA) is an association between the Brazilian companies CVRD and CADAM, Mitsubishi Corporation of Japan, and the IFC (World Bank) created in 1992 in order to recover kaolin from Rio Capim deposit, northern Brazil. Commercial production at PPSA started in August 1996 using a process comprising mining and beneficiation at the mine site, pumping through a pipeline and drying/loading at the port site on the Amazon river estuary. Presently, all PPSA production is concentrated on 82% <2um, high-brightness coating clay shipped in bulk. In this paper, a detailed description of the development of PPSA beneficiation process is presented. The results of laboratory and pilot plant studies under- taken to develop alternative grades of clay, such as delaminated and calcined kaolins, are also discussed.

Jan 1, 1998

By D. D. Harbuck

Previous studies at the US Bureau of Mines (USBM) have shown that only 70% to 80% of the germanium in domestic zinc process residues can be extracted during H2S04 leaching. To increase germanium extraction, the USBM developed and researched the hypothesis that minor amounts of germanium and zinc silicate, present in zinc calcine, dissolve during the leaching stages of zinc processing, forming soluble germanium and silica gel. This silica gel then selectively adsorbs germanium from solution, rendering the germanium insoluble. Testing showed that as the amount of formed silica gel increased, the amount of insoluble germanium in the zinc residue increased. Several processing alternatives are presented for overcoming this problem.

Jan 1, 1994

By J. B. Hiskey

Thiourea is a reagent capable of complexing gold and silver. With the proper oxidant, thiourea can effectively dissolve metallic gold and silver. A thiourea leaching system possesses potential advantages over conventional cyanidation including acidic solutions instead of alkaline, cationic complexes in contrast to metal-cyanide anionic complexes, and faster leaching rates with acidic solution of thiourea. Generally, the rate of metal dissolution in thiourea solutions is fastest when ferric ion is employed as an oxidant. Acidic thiourea solutions for certain applications could offer a nontoxic and noncorrosive option for processing gold and silver. This paper provides information regarding the fundamental chemistry of the acidic thiourea system, and reviews the dissolution of both silver and gold in acidic solutions of thiourea. The recovery of gold and silver from acidic thiourea solution is discussed.

Jan 1, 1981

By Dan Plazak

The authors are to be congratulated for presenting a simple and practical tool for quick estimates of ground water flow rates. At the risk of detracting from the simplicity of the method, I would like to suggest a slight refinement to the equation as presented. As the authors noted, the Jacob-Lohman equation (1952) assumes confined-aquifer conditions. To use confined-aquifer equations in water-table aquifers, Jacob (1963) presented a correction to convert water-table aquifer drawdowns [ ] to equivalent confinedaquifer drawdowns [ ]:

Jan 1, 1994

By O. A. Bascur

Based on current sedimentation theory an on-line thickener model was developed and coupled with an extended Kalman Filter to obtain additional information such as the compression zone level and concentration, a corrected underflow concentration, the inventory, and some rheological information. The on-line model was installed and tested for robustness for periods up to three days in an industrial environment giving good results. Emphasis was given to signal processing and selecting the appropriate input variables for filtering. The analysis of the thickener from a phenomenlogical point of view provides for better operation, establishes the limiting operating conditions, and assists in the design of control strategies.

Jan 1, 1986

By J. D. Patsey, G. T. Lineberry

Introduction A computer program was developed for analyzing drum-type hoists before modifying an existing system or designing a new one. Its use permits the preliminary evaluation of a system before seeking technical assistance from mine hoist designers and manufacturers. The user-friendly program accepts a variety of data and analyzes hoisting systems for any balance state. The program can be used to calculate skip capacity to yield a desired production rate, solve for drum face width, select a permissible wire rope, estimate total horsepower of the hoist plant, and estimate annual power cost. Whether required for a large mining complex or for a relatively small operation, a hoisting system must be carefully designed to ensure the efficient, reliable, and safe flow of material. Because shaft sinking and hoist installation can total between 2.5% and 3% of the cost of opening a deep mine, proper hoist selection is critical. Today&apos;s mining engineer has at his disposal the most powerful design and analytical aid ever, the microcomputer. There is, unfortunately, limited software for the study of hoisting systems, unlike that for other materials handling equipment (Manula and Albert, 1980; Prelaz et al., 1964; Bucklen, 1969; Thompson, 1985). HOIST reduces a time-consuming set of calculations to a concise package of interrelated subprograms. A literature review revealed no common-user programs to analyze hoisting systems, although at least four major hoist designers/manufacturers/installers have their own in-house programs. To provide a tool with which the mining engineer could preliminarily analyze a materials hoisting system or could check the calculations of a hoist contractor, a computer program was developed. HOIST was written in BASIC for the IBM-PC for ease of program adaptation and to encourage field use on compatible systems. Details of program development are omitted, since the basic principles of hoisting analyses are relatively straightforward, simple, and readily accepted (Harmon, 1973; Nordberg, n.d.; Adler, 1957). Program features, intended usage, and benefits of the computerized solution are emphasized over theory development and mathematical rigor. Background The mine hoist system that is selected and installed at a mine is the "lifeline" of that mine, with installations lasting 20 years or more. Thorough study is warranted to ensure that productivity demands are met at a minimum cost per ton. The increased cost of a large, powerful, high-speed hoist must be offset by increased production to justify its selection. To optimize this tradeoff, an extensive hoisting analysis should be performed. The analyses to properly size the skip (or cage), the drum, and the hoist drive are conducive to computerization, permitting rapid evaluation of changeable operating and design parameters, such as velocity, acceleration, state of balance, and productivity demand. The program is particularly useful in conducting sensitivity trials, such as investigation into the effect of change of productivity on skip capacity and on horsepower of the hoist drive. HOIST is currently limited to the study of drum-type hoists with cylindrical drum(s). However, only minor changes to the program would permit analysis of friction hoists and conical drum configurations. Model development and testing The program is based on accepted equations and physical relationships. Examples of manual calculations formed the basis for decision points and program branching. Data is input in the order that it would be needed if the problems were solved manually. The choices are arranged likewise. HOIST was developed in sections, with manual solutions performed to check program logic. The testing became more rigorous as sections were completed. Output from one section becomes input for following sections, as appropriate. The simplified flow diagram of HOIST is given in Fig. 1.

Jan 2, 1987

By Refik Elibay, Lawrence A. Williamson, George D. Barnes

Under an extremely aggressive schedule, final design of 13.5 km (8.4 miles) miles of 8.2 m (27 ft) diameter deep rock tunnel, 322 ML/day (85 million gallons / day)submersible pumping station and associated facilities were accomplished ahead of a federal court mandated consent decree schedule. Challenges overcome by the project team in enabling timely completion of the construction documents will be presented. Discussion includes evolution of final design, consideration of future O&M requirements, and risks identified for construction and operations, together with measures to manage and proactively prepare for such risks.

Jan 1, 2005

By D. R. McGregor, B. V. Clingan

A practical application of recent design concepts makes it possible to design a column cell to fit a specific set of conditions. The design and operating parameters of a column cell installation that replaced a conventional two-stage copper flotation cleaning circuit at Magma Copper Co., San Manuel, AZ, using these design concepts is described. A survey of other mineral processors using column cell technology was conducted. The results of this survey are also discussed.

Jan 1, 1988

By E. Suoninen, K. Laajalehto, L. Kartio

Efficient separation of pyrite from other sulfides is of great importance for the metallurgical performance of flotation processes. In this work Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) were used to study the surface chemistry of pyrite in depression, activation and xanthate adsorption under conditions of controlled potential. Modifications of pyrite surfaces after treatment with depressants (lime, sulfur dioxide, sodium cyanide) and after activation with metal ions (Cu, Pb) were studied. The principal adsorption product identified on pyrite was dixanthogen whose formation started at about +0.15 V and +0.25 V (vs, SHE) in ethyl and amyl xanthate solutions, respectively. Copper xanthate was formed on copper(II) activated pyrite. Activation mechanism of pyrite by copper(II) salts is likely to be electrochemical where copper occurs as copper(I) on the surface of pyrite. Effective depression is achieved by sulfur dioxide and sodium cyanide. Depression at high pH is due to formation of iron(III) hydroxides. Calcium ions do not affect the electrochemistry but adsorb on pyrite and reduce the surface sites for dixanthogen adsorption.

Jan 1, 1995

By Dipl. -Ing. Mertens

Gentlemen: I am pleased and regard it as a priviledge to give you a report on rapid roadheading with heading machines in the coal mining industry of Western Germany. Importance of Heading Operations in the West German Coal Mining Industry Every year about 770 km of headings are driven In the seams of the West German coal mines, most of them gate roads, the rest rise headings, to open new faces. In thick seams the heading operations are carried out entirely in the coal, in thin seams the country rock has to be ripped. The total length of 770 km corresponds to a rock volume of roughly 9.5 million m3; this figure underlines the importance of the heading operations in the coal mining industry of our country.

Jan 1, 1970

By Ewan Alexander

"As human beings, we have managed risk since the dawn of the ages and have been adept at doing so. In order to survive, we hunted or gathered. If we did not take enough risk, we died. If we took much risk, we died (Fig. 1). As individuals and tribes, risk had to be optimized to maximize our chances to thrive, as individuals and as tribes.In today’s world, the risks are vastly different, but in order to thrive, these must be managed. And no industry knows this as much as mining. In fact, the International Council of Mining & Metals (ICMM) has proposed the Critical Risk Model (Fig. 2) as a means of identifying critical risk, critical controls and associated performance standards. The ICMM focuses on sustainable development performance in the mining and metals industry. It has 23 members, representing some of the largest mining companies in the world.This approach is going to help the mining industry. But it must be applied effectively, with the acknowledgment that the system alone cannot be effective. We can say this confidently, as even companies known for the strength of their risk and safety management systems continue to experience significant incidents, and, in some cases, catastrophes. Why does that happen when all safety metrics, including injury rate, are pointing in the right direction? In the view of the author, it is only when leadership, culture and systems work in complete harmony that the resilience of an organization to manage its significant risk is at an optimal level. It remains an ongoing leadership challenge to maintain that balance and the optimal mindset in the organization. So how do you maintain that special balance?Let’s start with a basic premise. Leadership, supported by simple effective systems, creates culture which creates outcomes. Everyone going home safely is an outcome, as is cost effective operations, and to achieve those outcomes efficiently, the organization must focus on the inputs. And those inputs include effective leadership, effective systems (for the purposes of this article, risk and health, safety and environment (HSE) systems), good planning, stable operations and competent workers. This article will focus on gaining maximum performance from your risk management system."

Oct 1, 2016

By S. Aktas

The present work describes an investigation of a hydrometallurgical process for the recovery of mercury from spent silver oxide button cells. The cell paste was leached in nitric acid to solubilize silver, mercury and zinc. The optimum leaching conditions, in which mercury is entirely converted to Hg2+ ions and, therefore, does not co-precipitate with silver chloride during treatment with potassium chloride solution, were 1.0 M HNO3, 45° C, 1 hour and 200 rpm. After the silver was removed from the solution, mercury was cemented out with zinc powder with an efficiency greater than 99%. In the cementation experiments, the amount of zinc powder, shaking rate, temperature and solution pH were investigated in detail. The mercury recovery (%) increased as the amounts of zinc powder and the temperature were increased. Zinc hydroxide was precipitated from the waste solution by the addition of sodium hydroxide. The Zn(OH)2 precipitate was then converted to zinc oxide. The proposed process is proven to be simple, straightforward and environmentally friendly.

Jan 1, 2011

By F. K. Letowski

Leaching of zinc sulphide concentrate by nitric acid which is simultaneously regenerated by oxygen in the reactive froth has been investigated. The reactive froth was formed by a recycled zinc sulphate electrolyte containing nitric acid, a mixture of gaseous 02 and NOx, entrapped in the foam and particles of the zinc concentrate suspended in the foam. In the reactive froth the multiple regeneration of nitric acid proceeded owing to the encapsulated oxygen and amount of nitric acid used can be considerably lower than in the continuous liquid phase. 93 to 97% of zinc was extracted to a solution containing 30 to 409/1 HNO, during 40 to 60 min of leaching in a batch reactor without regeneration of nitric acid. 50 to 100% of the consumed nitric acid was regenerated during continuous leaching in froth carried out in the ‘flotation column’-type reactor at 80 to 90°C and under pressure of 100 to 200kPa. The rate of HNO, regeneration in the froth was proportional to oxygen pressure and inversely proportional to nitric acid concentration in the froth. A two-stage process flowsheet is proposed. In the first, the reduction stage, removal of nitric acid from the leach solution directed to standard purification and electrolysis is carried out by its reduction to nitric oxide using fresh concentrate in the froth. In the second, the oxidation stage, nitric acid is continuously regenerated by oxygen in the froth.

Jan 1, 1995

By Adam Zanker

Smooth roll crushers are widely used as secondary crushers, operating most effectively when set for size reductions in a ratio between 3 or 4 to I. The feed supplied to these units varies from 13 to 102 mm in size and the product obtained ranges from 13 mm to about 20 mesh. Smooth roll crushers produce very few fines and absolutely no oversize. The diameter otfhe rolls varies with the clearance between them, feed size, and the coefficient of internal friction ofmaterial to be crushed, Detailed calculations of this relationship may be found in Unit operations of Chemical Engineering, (McCabe, W. L., and Smith, J. C., 1967, McGraw Hill, NY, Chapter 26, pg. 825). The geometrical arrangement of the roll crusher is shown on the accompanying sketch. A relatively simple relationship between the diameter of feed, the roll, and the gap between them is as follows:

Jan 6, 1980