Search Documents

By R. W. Barbaro, J. M. Mutrnansky

This paper presents a nonlinear integer goal programming model that optimizes a mineral production schedule while considering the penalties and bonuses based on quality variations in the final product. It involves five coal quality goals plus a profit objective in its formulation and uses the weighting method of goal programming for a solution. The goals to be sought involve the sulfur, ash, heat content, moisture content, and ash softening temperature of the blended coal product. The model is linear in its handling of most of these goals but uses a piecewise linear integer formulation for the sulfur and heat content bonus and penalty schedule. The model is applicable to any mineral product blended from several different sources and subject to a varying price dependent on blended product quality or qualities. However, it seems to be most pertinent to optimizing production schedules for coal deliveries to power plants. Accordingly, the model is applied to a hypothetical coal production problem where multiple coal mines are operated to supply a final blended product to a power plant. In this example, the price paid for the coal is assumed to be a function of five of the most important coal qualities. The problem is solved as a direct function of the coal supply contract, thus removing the necessity of determining the weighting coefficients on a subjective basis.

Jan 1, 1987

By Ralph P. Hackl

Ore at the Congress gold property, located near Goldbridge, British Columbia, is extremely refractory with most of the gold disseminated in fine-grained arsenopyrite. Metallurgical testwork conducted by Giant Bay Biotech Inc. indicated that biooxidation pretreatment was capable of increasing cyanide gold recovery from the ore to greater than 90%. To determine if the bioleach process could be successfully scaled up, a 225m' (7950-cu ft) commercial size bioleach reactor was built and tested at the mine site in 1989. At that time, the tank was the largest bioleach reactor ever operated. The objectives of the program were: • to ascertain if the biooxidation rates obtained in lab and pilot-scale reactors could be duplicated in a commercial scale tank; • to identify agitation conditions under which the process will function optimally; and • to demonstrate the bioleach process on a scale sufficient to satisfy the owners and potential investors.

Jan 1, 1990

By Morteza Gharouni Nik

Flexible Dilatometer Test (FDT) is one of the in-situ test methods for determining the deformational characteristics of rock masses. In this study, several dilatometer tests have been conducted in different geotechnical phases of site investigations by means of two types of FDTs. The purpose of this paper is comparison of the performance of these two types of dilatometers and analysis of the differences in the results of the tests.

Jan 1, 2008

By Jafar Khademi Hamidi

The Zagros long tunnel is one of the main components of Sirvan water transfer project in western Iran. It is approximately 48 km in length and consisted of two lots. The second 26 km lot of this tunnel is under construction by a 6.73 m diameter double shield (DS) TBM. The tunnel passes through several formations with wide range rock mass qualities. During the tunnel alignment, changes in rock quality were highly frequent from poor to very good. The encountered geological conditions required TBM operation to change frequently from hard rock to soft, dry to flowing, sticky to nonsticky ground (and vice versa), more often than expected. In the course of tunneling, the machine has encountered nearly many adverse geologic conditions. The most important problems have been sudden high volume water inflow into the tunnel, sticky ground, and gas seepage, all of which resulted in reduced TBM advance rates. This study will high-light two difficult ground conditions including large water ingress and sticky ground and also the related problems encountered by the TBM along 8 km of excavated tunnel. In sticky grounds, cleaning of the clogged cutter head caused many delays and contributed to additional downtime. Application of some operational modifications, including decreased TBM thrust showed satisfactory results in such cases. While reduced thrust resulted in reduced penetration rate, but the overall TBM advance was greatly improved by the increase utilization rate and elimination of down time related to cleaning of the head. To cope with high water inflow, application of preventive measures such as pre-grouting has proved to be a more efficientsolution. The sealing of ground water inflow also decreased seepage of dangerous H2S gas and other chemicals such as hydrocarbons accompanying the groundwater.

By Pieter C. van Aswegen, J. A. Brierley, C. L. Brierley

The bacterial-oxidation (BIOX®) process for the pre-treatment of refractory ores for gold recovery is marketed by BlOMlN Technologies S.A. The process was originally developed by GENMIN who is still providing testwork, design and commissioning assistance to BIOMIN. Since 1986 three BIOX® plants have been commissioned by GENMIN. A further two plants will be commissioned during 1993 and 1994. The commissioning and operational experiences from these plants are described in the paper.

Jan 1, 1993

By T. Brady, J. Johnson, J. Whyatt, B. Pariseau, M. Stahl

An elastic-viscoplastic material model allows for time- dependent rock mass motion in proportion to excess stress above the elastic limit. The model produces rounded stair-step curves of displacement vs. time that are similar to those obtained from recent borehole extensometer measurements made in the central portion of the Ross Shaft pillar at the Homestake mine. The work in progress, including two- and three-dimensional finite element analyses using the UTAH2/3 codes, indicates that the model is a step towards more realistic safety and stability analysis, but that inclusion of rock mass damage may be desirable.

Jan 1, 2000

By Boleslaw Tolwinski

This paper presents an algorithm for the de- termination of a production schedule for an open pit mine that satisfies all principal physical and economic constraints required by a realistic mine design. We propose to model the evolution of the mine over time as a sequential optimization problem or, equivalently, as a problem of finding a path with a largest value in a graph. Some preliminary evidence is provided that such a path can be effectively sought by an algorithm that combines a number of heuristic search rules, inspired in part by learning theories developed in Artificial Intelligence.

Jan 1, 1992

By Boris M. Vorobjev

The paper in question discusses a wide range of topics related to computerized coal mine monitoring systems starting with the history of development and application of computerized monitoring coal mine systems and finishing with modern trends in the design and updating of such systems. The paper focuses exclusively on methodological and technical aspects of computer-based coal mine monitoring systems and their applicability in both surface and underground coal mining operations.

Jan 1, 1989

By Krystyna Raszka, Jerzy Iskra

The paper presents results of spectrophotometric investigations concerning the adsorption of sodium oleate on silicon carbide in the presence of the cations of multivalent metals, applying the ATR IR technique with computer-aidedprocessing of the spectrum. The analysis of these spectra indicates the occurance of distinct OH and COOH bands in the pH range in which the hydroxy complexes of metals of the type MeOH+ and MeOH++ reach in the respective cases the highest concentration in the solution. The correlation of these results with those of flotation, measurements of the zeta potential confirms the proposed mechanism of activation of the flotation of silicon carbide, applying sodium oleate as a collector, the collection taking place over the adsorption of hydroxy complexes of the type MeOH+ and MeOH++

Jan 1, 1995

By J. Olsson

Introduction Stainless steel has by tradition been a common construction material for hydrometallurgy processes and the most common grades can be found amongst the ASTM 300-series, i.e. austenitic grades of type 304L, 316L and 317L. However, there are a number of new grades available today, which imply more cost effective solutions for those designing plants where good resistance to acids, containing the desired metal ions, often contaminated with chlorides and other halides, is the key issue. There are austenitic-ferritic or duplex grades having the same or even better corrosion resistance than the austenitic grades and approximately twice the strength, which enables design in thinner gauges, which in turn implies less weight and less cost. They have also excellent engineering properties, enabling fabrication of process equipment, machinery and different types of tanks. On top of that, they contain less nickel and molybdenum than their austenitic counterparts, which implies not only lower cost for alloying elements, but also a more stable price when considering the price fluctuations for these alloying elements during the last years. This paper describes briefly the family of duplex stainless steel and it presents a number of relevant corrosion tests where duplex grades have been compared with austenitic grades. The results have in several cases been verified by in-plant exposures in zinc and copper production plants. It also describes applications and experience of duplex grades within a variety of hydrometallurgy plants. Installations of highly alloyed austenitic grades will be described as well. The corrosion tests and service experience reported cover hydrometallurgical processes based on sulphuric acid.

Jan 1, 2007

By J. W. Jang, J. J. Moore, I. Iwasaki

The wear behaviors of grinding media with different chemical composition and microstructures in wet grinding of a quartz-pyrrhotite mixture were investigated under various environments. The marked ball wear tests showed that the wear rate could be minimized by a suitable combination of martensite and ferrite within the same ball. A ball composed solely of hard martensite exhibited increased wear under an oxygen environment, while balls composed of both soft ferrite together with hard martensite exhibited decreased wear due presumably to the difference in their passivation behaviors. The galvanic interaction between the two phases as well as among these phases and an electroactive mineral were investigated through electrochemical measurements under abrasive condition in a slurry. The rates of formation of passive film controlled the corrosion currents of the high chromium steel media. Corrosive wear and its effect on flotation are discussed using the passivation kinetics model thereby developed.

Jan 1, 1990

By YONGQIONG YANG, Ning Wang, CHONGGUANG LUO, LI ZHU, Hanjie Wen, SHENGJIANG DU, Hannian Gu

Niobium in kaolin clay from the Late Permian sequences was reported in the range of several hundreds of micrograms per gram and was considered as a potential resource for its high concentrations and large areal distribution. Ti-bearing minerals associated with kaolin clay were identified as the main host phase for niobium in some case studies. However, the correlation between the concentration of niobium and titanium is poor, and the types of Ti-bearing minerals and modes of occurrence of niobium are not clear. Typical kaolin clay samples from the Late Permian sequences from southwest China were characterized, and the final products derived from kaolin clay sample were investigated using XRF, ICP-MS, XRD, SEM, and TEM (EDS). The results reveal that there were three types of TiO2 mineral phases in the clay samples: (a) massive TiO2 minerals and (b) aggregates of nano TiO2 minerals did not contain niobium while (c) granular TiO2 minerals were the source of niobium from the EDS analysis. The granular TiO2 minerals included anatase and rutile, both of which were the sources of niobium in kaolin clay in the current study. The findings are of great theoretical implication for source and origin study of Ti-bearing minerals and guidance for separation and recovery of niobium from kaolin clay.

Nov 30, 2020

By S. W. Asihene, K. Osseo-Asare

The leaching and solution treatment operations used in the ammoniacal treatment of laterites depend on the ability to establish and maintain close stability relations between soluble metal ammine complexes and solid phases such as oxides, hydroxides, basic carbonates, sulfides and ammonium double salts. This paper presents a quantitative treatment of heterogeneous equilibria in ammonia/laterite hydrometallurgical systems, by means of several.types of hydrometallurgical phasedia- grams (e.g., Eh-pH, log [NH3 + NH4+] - pH, log [C02] - pH, log SO42-] - pH, log [Metal] - pH). Dissolution/precipitation phenomena associated with nickel and cobalt recovery and with magnesium scaling are discussed in the context of the phase diagrams.

Jan 1, 1979

By Manuel Gomez

This, report presents correlative data on ash and sulfur forms for Pittsburgh seam coal from Greene County, Pa. Prediction equations were developed for sulfur form distributions and washability characteristics. The equations developed were evaluated with an independent set of exploration core samples. It was demonstrated-that both sulfur distributions and washability characteristic's can be predicted from exploration core data ahead of mining. This information can improve the efficiency of selective mining techniques for the production of a uniform metallurgical coal product.

Jan 1, 1967

By Terry L. Logan, Arfon H. Jones, James C. Seccombe

Deeply buried coal seams [greater than 3000 ft (914 m)] are difficult and sometimes hazardous to test and complete due to coal sloughing, formation pressure anomalies and coal fine generation. Data collected while stimulating two deep coalbed methane wells located at the Gas Research Institute/Resource Enter¬prises, Inc. "Deep Coal Sean Project" test site in the Piceance Basin, Colorado, is presented in this paper. A single thick coal seam was completed openhole in each well. Core data, reservoir data, in-situ stress measurements, and pre-stimulation calibration test data were collected at the site to use in the design of the fracture stimulation treatments for both wells. A nitrogen foam fracture fluid treatment was selected for the first well and a linear gelled water for the second well. Treatment pressures were monitored with a downhole quartz pressure transducer. Atypically high treating pressures were observed, possibly indicating coal fines plugging at the fracture tip or increase in fluid viscosity caused by interaction of the generated coal fines with the fracturefl uid. In addition, a comprehensive fracture diagnostic effort was employed during the fracturing of the second well; namely, triaxial borehole seismic, seismic televiewer, hydraulic impedance monitoring, gamma ray log (in conjunction with radioactive additives in the sand), and temperature log. The results indicate a vertical fracture was created parallel to the face cleat as expected.

Jan 1, 1986

The Mine Safety and Health Administration (MSHA) academy in Beckley, WV, received enquiries from various segments of the mining industry concerning alcohol and substance abuse in the mining industry. The MSHA Director formed a committee, the Mining Industry Committee on Substance Abuse (MICSA), to deal with these enquiries. The committee met in April 1985 at the mining academy in Beckley. The MICSA committee expanded its membership to represent labor, management, and government agencies affiliated with the mining industry as well as government agencies dealing with alcohol and drug abuse. This expanded 18-member committee met for the first time in July 1985. At that time, two cochairmen were elected, one from labor and one from management. MICSA has spent time on education by sharing information on the issues and by calling in outside experts for advice and consultation. The committee also initiated several projects. These include a resource manual on substance abuse and employee assistance programs. Mine operators and labor unions can use these programs as guides. MICSA is also assembling statistics on substance abuse, particularly as applied to mining. And the committee commissioned an Education film, Substance Abuse, Is It Our Problem? (The results of a survey on drug use, given in Table 1, suggest that substance abuse may indeed be a problem.) The educational film, produced by MSHA, is an introduction to the problem of substance abuse in the mining environment. The film encourages mine operators, labor unions, and miners to analyze their individual circumstances to determine whether a problem exists. The film also offers ways to deal with the problem. And the film invites the mining industry to request additional information from MICSA. There is no single approach to substance abuse that will fit the need of every mining operation. As with any health, safety, or production problem, remedies must be site specific. MICSA's aim is to channel ideas to those who seek to help employees in a mining environment who seek to rid themselves of alcohol and substance abuse. As stated more formally: The Mining Industry Committee on Substance Abuse represents the efforts of labor, management, and government. The mission of the committee is to make the mining industry aware of the problems resulting from alcohol and other drug abuse and to recommend possible methods to remedy the problem. The function of the committee is to assist the industry in developing programs and resources to recognize and provide help for troubled employees, and thus reduce the risk of accidents, while lower absenteeism and increasing productivity.

Jan 11, 1987

By Frederik P. Agterberg

Mineral exploration consists of the acquisition of data and their interpretation to ascertain the presence or absence of uncertain events. In general, the amount of uncertainty decreases during exploration when targets become increasingly well defined. Decisions on further exploration and whether or not mining should be commenced are based on new information using both objective facts and subjective reasoning. Computers play an important role during all stages of exploration. Three recent books (References 1-3) on decision-making in exploration and mineral-resources evaluation provide additional background supplementing the papers in this volume and articles in scientific journals or other conference proceedings (e.g., References 4 and 5) dealing with the subject. Other new developments to be considered are that microcomputers are becoming increasingly important in the earth sciences (Reference 6), and so are applications of artificial intelligence (Reference 7). Microcomputer- based technology allows rapid communication between field parties and main office. Expert systems are becoming increasingly sophisticated aids for mineral exploration an can now contain objective rules based on statistical theory (Reference 8).

Jan 1, 1989

By Angelus S. C. Owili-Eger

The past decade has witnessed an unprecendented proliferation of groundwater computer models. Some of these numerical models were developed for the purpose of simulating groundwater movement in mining environments and predicting inflow rates into active mines. However, a general acceptance of these models as routine planning tools by the mining industry has been slow. Until recently, the major use of these models in the industry is by consultants. There are several reasons that have contributed to this situation. Some of these factors - include scarcity or non-existence of an appropriate data base information required for executing these models, the difficulty and costs involved in acquiring data, and the fact that the instructions for using these models are often too involved and time consuming. Today, however, the state-of-the-art technology has been advanced to a level where numerical models can be routinely used to simulate and predict inflow rates into active mining environments. Such environments include highly fractured (longwall) and deforming flow media. Features integrated into these comprehensive and yet easy to use models are double-porosity-pressure, multiphase, and non-darcian flow conditions. This paper reviews the role that computer modeling has played in mining-related operations by presenting several case studies and the state-of-the-art tools currently in use. Included will be some of the practical field applications that have been compiled during the past decade.

Jan 1, 1986

By B. C. Darst

Intensive efforts to develop potash use in agricultural production were begun in the US 50 years ago. Early growth was rapid and continued well into the 1960s. Many soils were inherently low in K, so crop responses to fertilization were often dramatic. Deficiency symptoms were common. Per-acre use has continued to increase in recent years, but annual growth rates have slowed. Soil buildup has occurred in some areas. Poor economics in the 1980s have been difficult to overcome. Efforts are now well under way to develop potential markets around the world.

Jan 1, 1987

By Kira Mizell, James R. Hein, Tracy Conrad

"The Ninetyeast Ridge (NER) extends roughly N-S as a topographic feature for 5000 km, from 31° south to 10° north (Fig. 1) where it becomes buried beneath the Bengal Fan at its northern end. These two geographic characteristics make the NER an ideal natural laboratory for determining the influence of latitude and terrestrial input to ferromanganese (Fe-Mn) crust formation and composition. In addition to study of geographic controls on crust composition, the NER is the largest feature in the Indian Ocean that may host crusts of economic interest.Crusts were collected from 9 of 33 dredge sites from 1.4° north to 26° south latitudes during the 2007 R.V. Roger Revelle Knox06 cruise. Nineteen samples were analyzed for 69 elements each. Nine bulk crusts and 10 layers from four crusts were analyzed. Three of the crusts sub-sampled for layers did not have the bulk crust analyzed and the weighted means for those layers were calculated to obtain bulk compositions. One sample was left out of the statistical analyses because it is phosphatized and chemically quite different from the other samples (Table 1).In order to determine changes in composition with latitude, Pearson product-moment correlation coefficients were calculated for the chemical dataset and latitude of dredge sites, as well as water depth. At the 95-99% confidence level, the following elements increase in crusts moving north along the NER: Mg, Ti, S, Cd, Ni, Tl, Mn, Ba, Co, Cu, In, Li, and Zn; and the following elements decrease northward: Fe, Fe/Mn, P, As, Sc, the rare earth elements plus yttrium (REY), Bi, Ge, and Pb. These correlations indicate that the iron oxyhydroxide component and its associated elements are more prevalent to the south, and the manganese-oxide phase and associated elements increase toward the north end of the NER. This change occurs between dredges D20 and D14 (Fig. 1), with crusts from D20 and south having Fe/Mn !1.0 and those north of D20 ""1.2, with the exception of the phosphatized crust. Crust composition also changes with water depth: Th, Ge, Pb, and the middle rare earth elements (REEs) increase with increasing water depth. Thorium commonly increases in deeper water crusts, which explains the higher Th concentrations in Atlantic and Indian ocean crusts in general compared with Pacific crusts (Fig. 2 and Hein et al., 2012), including the samples analyzed here with a mean water depth of 3584 m. However, water depth does not explain the latitudinal changes because the mean water depths of samples along the northern and southern segments of the NER are roughly comparable. Surprisingly, Si and Al, representing the aluminosilicate/detrital phase, do not correlate with latitude; that is as the ridge approaches and is buried by the Bengal Fan the Si and Al contents do not increase. However, overall, Si and Al have higher concentrations in NER crusts than in central Pacific crusts. Ba can be used as a proxy for primary productivity and statistically does increase to the north along the ridge in the direction of the equatorial zone of high biological productivity. Correlations of Mg, Li, and Zn with latitude may also reflect increased primary productivity at lower latitudes."

Sep 1, 2014