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By Liu Hongkang, M. J. Virnig, Yang Xianwan, Zhu Yun

A new technology for recovery of gold from loaded carbon developed by Kunming Institute of Technology is introduced. The principle, production practice and results are described.

Jan 1, 1993

By I. R. Miller

The purpose of this discussion is to try to offer some suggestions as to how the zinc and lead markets will perform over the balance of the decade, review some of the factors influencing production and come to some conclusions regarding prices. The past 2 years have been simply awful in terms of consumption, prices and overall profitability for the industry. In looking ahead to the year 2,000, it is probably not a bad idea to look back about 20 years to see where we have been and how we got to where we are. Zinc consumption from 1950 to the early 1970's increased steadily and rather nicely at an annual average rate of close to 4.0%. It was starting in the early 1970's that things started to get volatile and at times, difficult for the industry. The general economic boom of the early 70's was marked by annual consumption rates close to 5.0 million tons, a level not seen again for over 10 years. The First Oil shock of 1973-74 was followed by the sharpest consumption drop in memory. In two years, Western World zinc consumption fell 27%. While our chart shows a rather dramatic recovery thereafter, the average annual growth rate since 1970 has only been a rather modest 1.5%.

Jan 1, 1992

By Yoginder P. Chugh

About 65% of the U.S. coal production (835 n tons was surface mined. A similar proportion of the Illinois basin's production (112 m tons) is also surface mined. The state of Illinois is the third largest producer of surface mined coal in the United States, after Wyoming and Kentucky. The Illinois coal basin encompasses Illinois, southwestern Indiana, and western Kentucky, as shown in Figure 1 (dotted lines). The estimated surface mineable coal resources in the basin amount to about 27 billion tons, and about 69 m. tons of coal is surface mined annually (Tab1e I).

Jan 1, 1981

By R. L. Atwood

This paper discusses the metallurgical and Manufacturing input to Merrill-Crowe plants. Topics treated are pregnant solution chemistry, clarification, degassing, zinc addition, product filtration, accounting, and costs.

Jan 1, 1985

By Glenn M. Boyce, Timothy R. Coss

Microtunneling first appeared with some regularity in the United States in 1987. Until then, only Japan and Germany utilized this method of construction. Its high costs initially limited its application to special situations. The last ten years have seen the use of new pipe materials, new machines, new cutterheads, new techniques, and an average growth of30 percent each year. This paper documents the growth and changes that have occurred with microtunneling. Based on current industry practices and advances from abroad, this paper postulates what the next ten years may hold.

Jan 1, 1997

By John H. Smith

Because of increased pressure from Federal & State Regulatory Agencies, most acid flows will require some sort of treatment prior to being discharged to receiving streams. In many industries, the volumes of liquors are large and their acid content varied. Pressure to minimize costs of waste treatment equipment and land usage makes development of a treatment process incorporating these desires mandatory. "Standard" methods of acid neutralization with lime have been known for years, however, the volume and characteristics of the resultant precipitated solids can create a disposal problem. Also, when standard lime treatment is used, the settling characteristic of the precipitated solids is normally slow. In some instances, the necessity of added dissolved solids removal, (such as iron, needing aeration) add to the problem of concentrating neutralized solids. In a paper published in the September 1970 issue of "Coal Age," *the results of extensive test work by personnel of the Homer Research Laboratories of Bethlehem Steel Corporation, Bethlehem Pa., were reported. This paper dealt specifically with development of a flow sheet to treat acid mine drainage (hereafter referred to as AMD) from coal mine operations. Regulations on discharged water required basic pH and low dissolved iron content after treatment. Liquid flows of over 9 MGD from

Jan 1, 1972

By William K. Brown

Are the results of an exploration program worth the cost? This is a question I suspect many of you are familiar with and, theoretically at least, it is an easy question to answer. The answer, of course, lies in comparing the future earnings stream the program is expected to generate, to the present value of the cost of carrying it out. While historical costs can be determined without much difficulty, estimating the value of a future earnings stream involves all sorts of assumptions regarding future costs, metal prices, inflation rates and an appropriate discount factor; and in the context in which the question arises, requires additional assumptions about mineral deposits which have yet to be discovered. As a practical matter, this kind of approach isn't likely to produce a very convincing answer; certainly not one convincing enough to satisfy a skeptical audience; nor one likely to temper the illusions of recent converts to mineral exploration, who are convinced that if enough money is spent, profitable discoveries will inevitably follow. Within broad limits, however, I believe it is possible to analyze the costs and results of gold exploration in the U.S.A. over the past 20 odd years in a useful manner. And while such an analysis is imperfect, it will provide some insight into this fascinating subject.

Jan 1, 1983

By N/A

finally, but not least, the staff of Vaal Reefs Chemical Laboratory for their assistance and patience with the introduction of a new technology,

Jan 1, 1991

By A. Porvali, V. Agarwal, M. Lundström

Hydrometallurgical recovery of rare earth elements (REE) from NiMH battery waste can be performed using sulfuric acid leaching followed by selective precipitation as double salt (REENa(SO4)2•H2O) by adding Na2SO4 as a precipitating agent. The formed double salts can be treated further with NaOH solution to form REE hydroxides. This study focuses on metamodeling of a simulated flowsheet with design of experiments (DOE). Based on literature survey, a process flowsheet was developed using HSC Sim software. The created flowsheet focuses on circulation of solution containing Na+, K+, SO42- ions and impurities liberated in the NaOH treatment of double salt precipitate. The effect of seven parameters (P1-P7) on seven responses (R1-R7) were modeled using central composite design (CCD). INTRODUCTION Nickel metal hydride (NiMH) battery waste can be considered as an urban mineral due to the presence of valuable metals like: Ni, Co and rare earth elements (REE) (Larsson et al., 2013). In NiMH battery waste leaching experiments, sulfuric acid has often been employed as a lixiviant (Pietrelli et al., 2002,Zhang et al., 1999,Rodrigues and Mansur, 2010,Porvali et al., 2018). The key advantages of sulfuric acid are its stability and cost-effectiveness compared to other mineral acids such as HCl and HNO3. However, the usage of sulfuric acid in NiMH battery waste leaching poses simultaneous challenges and advantages. Limited REE solubility can be taken as benefit when recovering REEs double sulfates after solid-liquid separation. However, sodium and potassium hydroxide, present in electrolyte residues in the battery waste, can cause in-situ precipitation already during leaching due to limited solubility, thus decreasing the total REE recovery (Porvali et al., 2018). However, this problem can be circumvented by washing the electrolyte residues off the raw materials. Subsequently, the REEs may be precipitated in bulk as a mixed double salt out from the solution at very low pH with minimal co-precipitation of Ni and other metals. This relatively easy separation method can be extremely advantageous in the case of such a complex solution matrix with relatively high REE concentrations (conc.). Once REEs have been precipitated as double sulfates as per eq. (1) (Porvali et al., 2018), the resulting double salt precipitate lacks applications without further treatment. Direct thermal treatment would generate sulfur dioxide emissions and likely require high temperatures in order to transform double sulfates into REE oxides. Furthermore, the precipitate contains Na ions, which would need to be removed by chemical treatment from the calcined REE product. In the context of circularity of raw materials, it can be taken of a remarkable benefit if the sodium and sulfur present in the double salt could be reused instead of wasting them into the side streams. To that end, in this simulation study, the double salts are converted by dissolution and precipitation to hydroxides which are readily treatable, e.g. with total dissolution and solvent extraction, for further purification (Abreu and Morais, 2010):

Jan 1, 2019

By W. Bassow

In June 1972, when the United Nations convened its historic Conference on the Human Environment, only 24 countries had established government agencies with environmental responsibilities. Of these, 11 were in the industrialized world, 13 in the Third World. By 1985, the number had dramatically surged to a world-wide total of 145, with the greatest growth among the developing countries to 110, an increase of almost 1000%.

Jan 1, 1988

By F. G. Schora

The Institute of Gas Technology (IGT), under sponsorship of the U. S. Department of the Interior, Office of Coal Research (OCR), and the American Gas Association (A. G. A. ), has been undertaking the development of one of several processes to convert coal to high-Btu gas as a means of supplementing natural gas supplies. It is anticipated that there will be a significant need for such gas in the foreseeable future in order to meet the ever increasing demands for this preferred fuel form. HISTORY The development of the HYGAS® Process is based on various studies conducted at IGT starting back as far as 1945. Initial work was directed toward production of synthesis gas with subsequent catalytic methanation. By 1964 the concept of the direct hydrogenation of coal to produce methane noncatalytically was well-founded and the chemistry was reasonably well established. Work up until this point in time was financed by the American Gas Association. In 1964 the U. S. Department of the Interior, Office of Coal Research joined with A. G. A. to support the program. The objective at that time was to develop the necessary know-how to enable the design of a pilot plant, a necessary step in the ultimate commercialization of the process. Work for the next three years (1964-1967) emphasized investigation of fluidized-bed technology in the hydrogasification step, where moving-bed technology had been previously employed, as well as identification of commercially available catalysts acceptable for catalytic methanation of the CO and hydrogen in the hydrogasifier effluent under operating conditions in the system. By 1967, the preliminary design of a 3 ton/hr pilot plant had been finalized, and IGT received authorization from OCR to proceed with the detailed design and construction of that facility. The pilot plant was designed to study the following problems:

Jan 1, 1972

By Salvatore] [Parand

Deep well disposal is a much used and abused term which is the panacea for wastewater disposal in some minds and creates near hysteria in others. It can be the answer to a difficult waste disposal problem, or if improperly employed, can create more problems than it solves. My purpose in this presentation is to focus on the value and limitations of deep well disposal as expressed by New York State's experience and policies. To he sure, I feel a place for such practices docs exist if adequate safeguards are utilized. I shall give a broad brush approach to New York's legislative, geologic and operational concerns and speak briefly on some case histories. I shall not delve deeply into the technological details since I am not an expert in mining exploration or well drilling.

Jan 1, 1973

By S.K. SHARMA, ANKUSH GALAV, G.S.P. SINGH

This paper proposes a hydromechanically coupled numerical modeling approach to quantify the influence of various parameters on the mechanical and hydraulic performance of protective water barrier pillars (PWBP). The results are validated for two case studies having pillar widths of 16 and 42 m at cover depths of 136 and 190 m and water heads of 25 and 141 m. The outcome can be significantly helpful in the rational design of these pillars in underground coal mines.

Mar 1, 2023

The main goal of this paper is to present readers with recommendations for choosing coaxial cables appropriate for mining applications of Time Domain Ref 1 ectometry (TDR) to monitor rock mass movements. Prior to discussing the recommendations, mining applications are illustrated with examples and the operating principle of TDR is discussed briefly. Items that affect the result of the monitoring system performance include the coaxial cable selected, the grouting material used, and the installation procedure.

Jan 1, 1986

By David B. Ashley

Risks in underground construction are often viewed as technical in nature; "running ground, " "squeezing ground" and "chimneys" are terms that appear in construction managers' nightmares, and occasionally in their underground projects. Financial consequences of these and other project risks are reviewed. Special attention is paid to sources of cost overruns. From this study a structure evolves for setting priorities for risk management actions; these actions can also be tested for impact and potential effectiveness. Finally, case study reviews of six underground projects indicate the "state of the practice" for financial risk management.

Jan 1, 1983

By M. J. Lowe

National Institute for Occupational Safety and Health (NIOSH) studies show that 43.5% of surveyed coal preparation plant workers had noise exposures exceeding the Mine Safety and Health Administration Permissible Exposure Level. Sound levels around vibrating screens in these plants often exceed 90 dB(A). NIOSH is currently developing noise controls for horizontal vibrating screens. To characterize noise sources, NIOSH researchers performed sound pressure level (SPL) measurements on a vibrating screen at their Pittsburgh Research Laboratory. The results show that the entire screen contributes to noise below 1 kHz and the vibration mechanism housings are most significant above 1 kHz. Constrained layer damping (CLD) treatments and an enclosure were used to reduce mechanism housing noise. These were evaluated using sound power level measurements according to ISO 3744. The CLD treatments reduced the A-weighted sound power level by 3.1 dB in the 1 to 10 kHz one-third-octave bands. A panel-on-frame vibration mechanism enclosure using various types of panels further reduced the A-weighted sound power level from the CLD configuration in the 1 to 10 kHz one-third-octave bands by 3.7, 4.0, and 3.9 dB for aluminum, steel, and Dynalam panels, respectively. The combination yielded a 7 dB reduction from baseline in A-weighted sound power for the same frequency range.

Jan 1, 2010

By John A. Shuster

INTRODUCTION Controlled ground freezing for mining and construction applications has been in use for over a century. Despite the great technological evolution which has occurred during this period, ground freezing is still used on projects today with much the same basic technology as that used originally over 100 years ago. Major developments have occurred in the separate fields of frozen soil mechanics, refrigeration, and heat transfer analysis. However, except for a few projects in Europe and Asia, these developments have not been combined to upgrade ground freezing techniques to their potential level. In view of this situation, it is believed desirable to examine the art of ground freezing in light of recent technical developments, together with highlights on some of the apparent advantages, disadvantages and economics of the various alternative approaches. The purpose of this paper is to attempt such an examination, with particular emphasis on the practical application of presently available technology. GENERAL ADVANTAGES AND DISADVANTAGES Ground freezing may be used in any soil or rock formation, regardless of structure, grain size or permeability; however, it is best suited to soft ground rather than rock conditions. Freezing may be used for any size, shape or depth of excavation and the same physical plant can be used from job to job despite wide variation in these factors.

Jan 1, 1997

By E. J. Donovan, O&apos

The use of Dynamic Analysis techniques in the design of conveyor systems is extremely limited. The most frequent use of the technique is in large and expensive systems where the emphasis is on insurance against failure caused by catastrophic tension waves. This paper sets out to illustrate a much wider range of applications where dynamic analysis has been successfully employed. The examples chosen deal with identification and correction of dynamic low tension problems, the variability in take-up movement as other system parameters change, the requirement for proper tuning of starting controls and finally the absolute necessity for a complete understanding of the entire system when specifying brakes for critical applications. The intent of the paper is to get designers to view a conveyor as a system of interacting flexible components rather than as a single rigid body.

Jan 1, 1993

By J. Hazen, R. Jenner

This project was developed at the PCS Phosphate Mine in Aurora, NC. This site includes a surface mining operation, beneficiation plant and chemical processing facility located in the coastal plain of eastern North Carolina. The phosphate ore being mined at this operation is a 10 to 12 meter (35 to 40 foot) thick colloidal deposit located approximately 30 meters (100 feet) below the ground surface. The ore is pumped to the beneficiation facility where it is separated into clay, sand and concentrate streams. The concentrate product is utilized at the chemical plants to produce a wide range of products including fertilizer, industrial phosphates and animal feed products. The Cyclone Dike Builder (CDB) project developed a technique for dewatering the beneficiation tailing sand stream and providing innovative placement for dike construction. Future material balance requirements at the PCS Phosphate mine required an improvement in tailing sand placement technique to accomplish strategic objectives. The water volume of the sand slurry forces significant quantities of sand out of the dike profile during deposition. PCS Phosphate and MetPro Supply of Florida developed a mobile high-density hydro-cyclone station to remove most of the water and significantly increase the density of the sand being placed for dike construction. This high-density sand slurry is then effectively controlled using minimal heavy equipment operation.

Jan 1, 2004

By Surendra K. Mishra

Recent land ban act has put pressure on industry to decontaminate the waste streams before they could be discharged. However, for both metal and organic contaminated wastes, there are commercial incentives to recover usable resources. Recent technology developments have helped meeting such objectives. This paper reviews developments in treatment technologies for industrial wastes. Major chemical groups used in waste treatment are summarized.

Jan 1, 1994