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By M. K. Han, K. N. Han, P. B. Queneau, W. J. Dawson

The development and scale up of hydrothermal synthesis processes for manufacture of high performance materials is discussed. Traditional hydrometallurgical processes are reviewed, leading into a discussion of process development concerns for manufacture of modern materials. Three case studies are presented, including a piezoelectric ceramic, barium titanate for multiyear capacitors, and high purity chromium metal. Factors for selection of reactor design are presented, as well as results of scale-up studies on the three products.

Jan 1, 1993

By L. C. E. FEIO, R. RAMSDEN

In many parts of the world deep level mining relies heavily on the use of refrigeration for providing safe thermal underground conditions. The trend in South Africa in recent years has been to locate the refrigeration plants on surface and to use these plants to chill water that is then distributed throughout the mine. The surface cooling installation normally consists of a pre-cooling tower in which water is first chilled before it is sent to one or more refrigeration plants for further cooling. Presently, the majority of these refrigeration plants use CFC refrigerants; however, to conform with the Montreal Protocol, these plants will have to be replaced or converted for use with alternative refrigerants. The optimum design criteria for installations using the new generation of refrigerants will be affected by their characteristics and are likely to be different from those currently in use. In light of these developments the industry is examining a number of alternative systems for future installations including water vapour refrigeration. Factors that affect the decision on the type of refrigeration system to be used in mine installations are reviewed. INTRODUCTION Gold mining has been carried out in South Africa for over 100 years and most of the reserves close to surface have been mined out; this has led to mining taking place at greater depths, approaching 4000 m below surface. One of the consequences of operating at these greater depths is that it is necessary to install refrigeration plants to cool the ventilation air so as to provide safe and healthy working conditions. With the current low precious metal prices there is pressure on mines to cut costs and in recent years there has been considerable effort devoted to the design of more cost effective and efficient refrigeration plants and cooling systems. In the last 10 years there have been many studies into the use of ice for specific applications (Eschenburg et al., 1986; Hemp, 1988 and Ramsden and Lloyd, 1992) and at present there are three ice making plants in operation on South African mines, each of which produces ice in different processes. In addition, detailed design studies have been carried out on the "split ammonia system" (Napier and Patterson, 1992). In this refrigeration system the evaporator is located underground close to where the cooling is needed, whilst the condenser and heat rejection system is on surface. As far as refrigeration plants are concerned the trend has been to move away from standard package units to custom built refrigeration installations. This has given the design engineer greater flexibility in the choice of key components for refrigeration installations. For example both screw and centrifugal compressors are used, the heat exchangers for the evaporators and condensers may be either plate or shell and tube, and in a number of installations evaporative condensers are used. In addition, the following refrigerants are in use, R12, R22 and ammonia. The acceptance of the Montreal Protocol and its amendments by the South African government will restrict the use of CFC refrigerants and it will be necessary to re-evaluate various refrigeration systems, including those that do not use conventional refrigerants, such as air cycle and water vapour systems, for new surface installations. Although new systems and refrigerants are being developed, only the following refrigeration installations will be compared in this paper: - a refrigeration system using R134a which has properties similar to R12 - refrigeration system using R22 or a new alternative refrigerant with very similar properties - an ammonia refrigeration system - a water vapour refrigeration system The benefits of new cooling systems are not discussed in detail, since they are largely mine specific and outside the scope of the present paper. Since the optimum design for an air cycle system (del Castillo, 1988) is dependent on the mine layout, this system is also not included.

Jan 1, 1993

By L. M. Petrie, D. C. Marozas, S. E. Paulson

The US Bureau of Mines (Bureau) is conducting research to evaluate the potential for developing an in situ leach mining process that will selectively extract manganese from oxide ores, leaving gangue relatively undisturbed. To accomplish this, a geochemical approach based on deposit-specific information, such as mineralogy and geology, is used to constrain the operating parameters of the system. Among the studies being conducted are: • leaching experiments to define reaction mechanisms and kinetics, • detailed petrologic characterization at the microscopic scale to assess manganese distribution and leaching efficiencies, • deposit characterization and evaluation, and • development of potential manganese recovery schemes. Data from these studies are being used to develop engineering design information for an in situ mining process. Specific details of the Bureau's research project are discussed, including results obtained to date.

Jan 1, 1993

By K. Osseo-Asare

Metal recovery from solution, i.e., the formation of a solid product from a purified aqueous electrolyte solution, is increasingly becoming more than a simple matter of bulk precipitation. In many cases, operating conditions must be carefully manipulated to control the rate and yield of the precipitation/crystallization process, as well as the purity and physical characteristics of the solid product. A review is presented of the underlying physico-chemical processes, with emphasis on solution and interfacial chemistry. Opportunities for the integration of hydrometallurgical metal recovery and materials processing operations are discussed.

Jan 1, 1989

By Chester R. McKee, Amar C. Bumb, Kohei Kawakita

Unlike many other heavy metals, gold can be profitably mined in small operations because of the prices. One mining technique that seems ideally suited for small deposits of gold and for certain large, lowgrade oxidized disseminated deposits is solution mining. Solution mining generally requires lower capital investment and operating costs than conventional mining and milling and is safer and less degrading to the environment. Although gold has long been recovered by cyanide leaching following conventional milling, solution mining as discussed here gained momentum only in the past two decades, during which time alternative lixiviants instead of cyanide have been researched. Chamberlain and Pojar (1981) classified solution mining systems used today as three types, namely heap, dump, and in-situ leaching.

Jan 1, 1990

By Marie-Josée Banwell, Cyriac Sebastian, Giacomo Falorni, Sara Del Conte

Interferometric Synthetic Aperture Radar (InSAR) is a satellite-based monitoring technique that complements other in-situ methods for detecting and measuring surface displacement. Recent advances in data processing algorithms, coupled with the use of high-resolution satellite systems, make it possible to now provide high-frequency InSAR monitoring services, with updated results delivered every time a new satellite image is acquired. The advent of large, continuously updated data sets, however, brings new challenges, including the need to rapidly sift through the data to identify only those points showing relevant ground displacement information. This has been achieved by using trend variation analysis tools, that quickly isolate and highlight only areas of anomalous behavior. The paper focuses on project case studies where continuous InSAR monitoring has proven to be key in identifying displacement trend changes near tunnel alignments.

Jun 13, 2021

By Zhongxue Li, Shuang Gao, Zhixin Zhen, Yiqing Zhao, Xuan Qin

If not well-managed, a mine-tailings facility may become a major source of risks, endangering the community and environment, and damaging the reputation of the minerals industry regarding sustainability. Identifying, characterizing, and mitigating the hazards and risks associated with tailings facilities have been critical to the maintenance of community-safe and environmentally sound mine-tailings facilities. Herein, a complex network model for characterizing the hazards and risks associated with the lifecycle of tailings facilities is presented. In this approach, the hazards are modeled as vertices of the complex network, and the interactions among the hazards are modeled as edges of the complex network. The complex network for modeling the hazard and risk spreading of mine-tailings impoundments is analyzed and characterized by using network metrics such as the network density, geometrical characteristics, characteristic path length, network efficiency, and clustering coefficient. The degree distribution of the network obeys a power-law distribution, indicating that the network for characterizing the risk spreading associated with a tailings facility is scale-free. According to the results of calculations and existing research results, the network is ultrasmall-world. By analyzing the change of the global network efficiency under four kinds of different methods to remove network nodes and edges, network nodes with higher between centrality (BC) are identified as critical. The removal of those critical nodes helps mitigate risks associated with a tailings facility and reveals the vulnerabilities to BC attacks.

Jan 1, 2017

By M. H. Al-Dabbagh

In this paper, the authors outline the deficiencies of PERT/CPM as a method for scheduling complex projects such as mine development. In particular, PERT/CPM networks cannot accommodate logical nodes (events) or stochastic branches (activities). The Graphical Evaluation and Review Technique (GERT), developed by Pritsker and. co-workers, is introduced as an alternative to PERT/CPM that overcomes many of the deficiencies of the latter and enables a more realistic analysis of complex projects that are subject to significant uncertainties. A brief overview of GERT network structures and network analysis is given and a PC implementation of the method is described. The technique is illustrated by application to the development of an open-pit gold mine in Saudi Arabia.

Jan 1, 2002

By R. W. Wotring

Mr. Chairman, Officers, Members and Guests of the AIME, I want to express my appreciation for the privilege of being on your program at this meeting. Coal mining, in recent years, has become much more competitive than it formerly was. To stay in business, it has been necessary for coal mines to mechanize. This, in itself, has not been enough for after one has mechanized his mine, he must keep replacing the equipment with the latest type and model machines. We, at Olga, have been doing this very thing for the past several years. Olga No. 2 Mine is located at Caretta, West Virginia, in McDovell County, about twelve miles south of Welch, It is a shaft mine, operating in the No. 4 Pocahontas seam. The thickness in the area, we are presently mining, varies from five to six feet. In some areas the immediate roof is slate, ranging in thickness from a few inches to four and five feet; in other places, the sandstone lies on top of the coal, This sandstone is about twenty-five feet thick.

Jan 1, 1961

By Jamal Rostami

Continuous miners (CM) are the most popular underground mining machinery in soft rock mining, playing a dominant role in the production of minerals ranging from coal to evaporites while finding increasing use in salt and potash mines. Along with the ongoing technological advancements in the mining industry and the underground equipment, new generation of CMs offer several new features that are designed to enhance their operational capabilities and production rate. In addition to new bits and bit holders, one of the areas of improvement is the cutterhead design through computer modeling and simulation based on the full scale cutting tests. This paper discusses the state-of the-art CM technology and development of the computer models for design analysis and performance estimation of CMs. The general approach used in the modeling, along with the results of field trials for several projects will be presented.

Jan 1, 1998

By C. E. Capes

INTRODUCTION In the coal industry, ever greater amounts of fine coal must be processed due to the need to crush to finer sizes for impurity liberation in low cost physical cleaning processes. Fine coal processing is a major problem for the industry, both through the cost of disposal of reject fines and through the mining cost of lost coal values. Of the available disposal methods, impoundment has always been the most popular. In many cases, when the coal fines were of sufficient quality, froth flotation and expensive filtration methods were used to recover the coal in these waste streams. The coal fines are not always of a marketable quality, however, and flotation, due to poor yields and difficult dewatering, has always been an expensive and not necessarily profitable process. The oil agglomeration method is increasingly important as a technology for the treatment of fine coal-in-water suspensions. These fines can be preferentially wetted and agglomerated by many different oils mixed with the suspensions. Ash-forming impurities remain in suspension and are rejected when the agglomerates are recovered, for example, by screening. Agglomeration-based methods provide perhaps the only practical means for upgrading extremely fine coal to useful products on a large scale. As with froth flotation, oil agglomeration relies on differences in the surface properties of coal and impurities to effect separation. Whereas flotation be- comes less effective with particles finer than 200 mesh (0.075 mm) or coarser than 50 mesh (0.3 mm), there appears to be no lower limit on particle size for oil agglomeration while particles % in. (3.175 mm) diameter or larger can also be treated, if desirable. In addition to this ability to clean a broader size range of coal particles, oil agglomeration can produce a dense, coarse granular product of acceptable strength and low water content without the need for vacuum or thermal drying. The preferential wetting of solid surfaces by immiscible liquids has been utilized, if not fully understood, for a long time. Indeed Gaudin,229 in tracing the ancestry of froth flotation, refers to a 15th century oil-pulp kneading procedure in which water-wetted particles were freed under water from an oiled mass. An understanding of the physical chemistry involved in such

Jan 1, 1991

By Hajime Kitamura, Nobuharu Isago, Yuta Yamanishi, Kosuke Kawata, Hiroshi Yagi, Akira Matsuoka

Mountain tunnels are generally considered to be stable during earthquakes, however, it is known that the portal areas are prone to seismic damages. Characteristics in portals such as the location of the slope, modulus of ground deformation, and the change of overburden are different for each tunnel, and damage degrees are unclear. In this study, we reproduced the seismic behavior to investigate the effect on the tunnel portal by considering some parameters above, using simple static model tests and numerical analysis. As a result, the conditions of the slope condition and minimum distance from slope was confirmed to influence on the mechanical behavior of the tunnel portal during earthquakes.

Dec 1, 2022

By Jim Armbrust

JAMIE DAVIS: Our next speaker is Jim Armbrust, maintenance manager at Phelps Dodge, Morenci. Jim's presentation is titled "We Need More Training-How to Get the Biggest Bang for the Buck." We've talked a lot about preventative maintenance and we've heard several people talk about training. How do we train to use all these systems? How do we educate people? This will be a nice little wrap-up for us. JIM ARMBRUST: One common theme from this morning's talk is that we need more training. That's exactly what we'll be talking about for the next few minutes.

Jan 1, 1998

By Edwin J. Connell, O&apos

Investment in mining and related process facilities will be more costly and complex in the 1980s than ever before. Interest rates and inflation are soaring; regulations are expanding; and in order to achieve economies of scale, plant facilities and mines are getting larger. As the pace quickens, the time/cost circuit closes around the resource owner or developer. Larger modern projects cost more money and take more time to build. The longer it takes to bring a project onstream, the more it costs in interest, escalation, and lost production. One solution to the time/cost squeeze is to take advantage of systems developed by major contractors serving the mining industry. These contractors have been serving clients in planning and executing large and small projects for many years. They have developed systems which, if applied at an early point in the project's life, can be a significant benefit in development of mineral resources. The systems involve performance of feasibility studies, economic evaluations, and the project installation itself. First the Feasibility Study Feasibility studies can minimize risk through systematic evaluations while progressing toward the ultimate objective-an operating plant. Normally, studies are initiated with a minimum amount of specific information and a maximum number of as¬sumptions. Through the course of the study program, assumptions are continuously confirmed, refined, or rejected by facts until a sound basis for decision is available. High on the list of cost effective tools for evaluation is the use of a geostatistically derived sampling program that provides a highly accurate ore reserve estimate for economic evaluation. When a predetermined sample of data from the drilling program and bench-scale or pilot-plant tests are received, a detailed feasibility study may be started. This study can involve design of the mine,

Jan 10, 1980

By H. J. Marais, P. C. van Aswegen

The Biological Oxidation (BlOX®) Process for the treatment of refractory gold ores was commercialized in 1988. During the last decade, the technology has developed into a mature, commercially viable process, with five additional operations commissioned, including operations at Sao Bento in Brazil, Harbour Lights and Wiluna in Australia, Ashanti in Ghana and Tamboraque in Peru. With ongoing development, the efficiency and cost effectiveness of the process have both improved, making it an attractive alternative to conventional refractory treatment processes such as roasting and pressure oxidation. The bacterial culture is robust and can withstand the normal fluctuations experienced on an operating plant. The plants are simple to operate, making it ideal for remote areas. The scale-up potential of the process has been proven, and it can be applied to large refractory ore bodies. The process is environmentally friendly. Neutralization of plant effluents produces precipitates that comply with the most stringent environmental regulations.

Jan 1, 2000

By R. W. Barbaro, R. V. Ramani

Generally, production planning is concerned with the best use of fixed resources to determine a production schedule for one or more production units supplying one or more markets. Production scheduling determines when each production unit will be used and its production level. However, the production scheduling problems are intimately associated with the location of existing or new production units and processing facilities. Normally, mine location allows only a limited choice; processing plant types and locations are considerably more flexible. This paper presents a generalized multiperiod MIP model as an aid in determining the mine production schedule and the processing plant types and location to satisfy multiple markets. A brief description of MIP and how it has been applied in the mineral and other industries is discussed. A complete description of the model with an application to a coal preparation plant system is presented.

Jan 1, 1987

By John F. Schat, T. William Thompson

Laboratory data on the time-dependent compaction of porous rocks are presented, and various attempts to model this behavior are described. These lead to a discussion of the problems that arise in using laboratory data to estimate long-term effects. A method is suggested for combining laboratory data with information from the geologic record to estimate long term effects.

Jan 1, 1986

By Usko Anttikoski

This article deals with the extensive geotechnical soil and bedrock mapping system maintained in the Geotechnical Office of the City of Helsinki since 1955.Soil maps have been prepared to scales of 1:500,1:2000 and 1:10 000, and most recently in 1978 a new type of bedrock map was printed to a scale of 1:10 000, which covers the whole city area and particularly serves rock tunnel construction. A map showing the types of foundation building in the central city area, which will also serve underground construction activities, is currently being prepared. Since the geotechnical mapping system has been well received in Helsinki and the drawing of similar maps has also been undertaken in other Finnish towns, this mapping method is believed to be of interest to foundation engineers and tunnel constructors elsewhere too. THE GEOTECHNICAL CONDITIONS IN HELSINKI The geological structure of Helsinki, and of all Finland, presents two types clearly differing in character and age; bedrock and soil. The solid bedrock is Precambrian, while the soil dates from the Pleistocene Age and has mainly been deposited during and after the Ice Age. Thus the history of Helsinki only displays very old and very young formations, but nothing in between. The ground level in Helsinki is +62 at its highest and the sea bottom close to shore is -15 at its deepest. The deepest rockhead has been found to lie at the -70 level.

Jan 1, 1979

By J. M. Mutmansky

The SIMAN (SIMulation ANalysis) computer language is a general-purpose, discrete-continuous simulation language for modeling a variety of multi-component systems. The language has been described by its author in a textbook (Pegden, 1985) and in a paper (Pegden, 1986) and is available in a mainframe version, a minicomputer version and a microcomputer version. The language was designed for and has been extensively used for modeling manufacturing systems but possesses many features that are advantageous in the modeling of mining materials handling systems. Consequently, the authors have applied the language to the simulation of an open pit shovel/truck operation to test its usefulness for simulating mine materials handling systems. This paper presents a short background on simulation languages, the capabilities and modeling framework of the SIMAN language, a description of the application of SIMAN to a shovel-track operation and some results and conclusions on the use of the language for mining materials handling systems.

Jan 1, 1988

By G. Mbuyi Kamba, J. Patigny, E. Jacques

Traverse anemometry is still widely used today. In this paper an investigation of the influence of three factors which are believed to contribute to the resulting error of the method, is reported. They are the shape of the traversing path, the size of the vane anemometers and the air velocity pattern. These factors are experimentally studied on a test facility developed specially for this purpose. Taking into account the results of 576 measurement sessions, as well as published information, some preliminary conclusions are drawn, and additional questions are raised.

Jan 1, 1993