Search Documents

By Orville D. Mussey

During, 1956 the water used in mining iron ore in the United States amounted to about 2 billion gallons and the water used in producing iron concentrates-amounted to about 166 billion gallons. By 1980 an increase of about 65 percent is anticipated in the amount of water used for mining and beneficiating iron ore. Except for boiler-feed makeup water the quality requirements for water, for mining and beneficiating iron ores are not stringent. Adequate supplies. of water for development should be available at reasonable cost with the possible exception of some in arid regions.

Jan 1, 1961

By Y. Zeng

Experiments were performed under batchwise wet grinding conditions with dolomite mineral. The vibration signal was received by an accelerometer and transmitted to a mini-processor. The signal was first stored on a digital tape recorder (OAT) in voltage format during the grinding tests. The original signal was then re-sampled and converted into data format for IBM or compatible personal computer by a digital oscilloscope. The root-mean-square (RMS) and power spectrum was estimated on the time-domain vibration signal. A partial correlation analysis was applied to the frequency-domain signal to detect the non-zero correlation between the frequency bands and the operating parameters. A multiple stepwise regression was used to locate the key frequency bands for describing a particular operating parameter. After vibration analysis, the operating parameters in grinding, for example, the mill speed, the powder filling, the pulp density, the pulp temperature and the particle size were found to be strongly correlated with a few frequency bands. The grinding process could therefore be monitored using the vibration signal.

Jan 1, 1992

Although mineral commodities used to play and still play a very crucial role in the development of civilization over the centuries, their extraction, transportation, transformation and use are at present sources of great concern in terms of sustainability. Some of the most discussed environmental problems are in fact closely related to the utilization of minerals as materials and fossil fuels. The paper analyses the origins of sustain-ability weakness of mineral supply through Environmental Economics models, which have interpreted the phenomena of pollution and non-renewable resource depletion as a market failure. Conventional market tools have proved to be unable to perform an optimal allocation of those resources that are priceless or have open access. An external intervention is needed in order to reduce the excessive exploitation of environmental and natural resources. Some of the solutions proposed by policymakers and subsequently implemented by governments are briefly considered and the achieved results are discussed. In several cases the public intervention, where the attempt was to restore the sustainability conditions, has failed. Restrictive environmental protection regulations have resulted in severe limitations to the mining activity, without, on the other hand, achieving the expected results in terms of sustainability. Some of these regulations instigate unfair international competition practices among those producers who do care about the environment, but who have high production costs, and those who supply cheap raw material but whose low costs hide heavy environmental impacts. Nowadays, most of the world?s supply of minerals is being produced in developing countries, with severe global environmental impacts. As effective tools for monitoring the problem, sustainable development indicators could be used by policymakers to duly associate the comprehensive environmental impacts for each mining product, depending on its origin and extraction history.

Jan 1, 2003

By Ray E. Harris

New developments have occurred in Wyoming's industrial minerals industry since the 32nd Forum on the Geology of Industrial Minerals in Laramie, Wyoming in 1996. The soda ash trona and bentonite industries have experienced overall growth. Gypsum and limestone production have remained constant, but have the potential for dramatic growth. The mining of zeolite ceased in 1997. The struggling dimension stone industry has increased production, but development has lagged behind the schedule predicted in 1996. The construction of a container glass plant and associated production of glass raw materials, as predicted in 1996 and imminent in 1998, is now on hold due to unforeseen market factors. Increases in railroad and highway construction have, and will, greatly increase the production of construction aggregate for local uses. An iron carbide industry, not foreseen in 1996, is in the planning stages.

Jan 1, 2001

By S. Chander

The mechanism of oxidation of sulfur in pyrite is a function of the rate and driving force for oxidation. New evidence is presented in this article to show that at moderate potentials, a sulfur-rich hydrophobic layer is formed. Under ordinary conditions, the sulfur layer is covered with a layer of iron oxides, hydroxides, sulfate or oxy-sulfide ions. Under these conditions, pyrite is hydrophilic. In the presence of iron-chelating agents or iron sequestering ions, iron layer might not form. Under these conditions, sulfur-layer is exposed and pyritic might become hydrophobic. Stronger oxidizing conditions decompose the sulfur-layer, thereby making the surface hydrophilic.

Jan 1, 1992

By John B. Jones

New concepts in shaft kiln processing are included in the design of two large diameter shaft kiln plants now under construction. One kiln will be used to produce cement clinker at the Boettcher plant of the Ideal Cement Company at Fort Collins, Colorado. The other kiln is for the semi-commercial oil shale plant for Petrobras, the Brazil National Oil Company at Sao Mateus do Sul, Parana, Brazil. Investigations on application of the new concepts are proceeding in a portable pilot kiln. The shaft kiln has long been recognized as a method of gas-solids contacting having the following principle advantages: l. High thermal efficiency 2. Ability to handle a variety of feed materials with a wide range of particle sizes 3. Minimum investment and operating cost

Jan 1, 1963

By B. K. Mishra

The motion of the charge inside a grinding mill is of considerable practical importance. The dynamics of grinding mills have been the subject of study by a number of workers because it can accurately predict: i) the power drawn by the mill, ii) the distribution of forces inside the mill, and hence the wear rate of balls as well as the liners, and iii) mass transport of milled product through the porous ball charge. Some of the earlier analyses of the motion of a charge of particulate material in a tumbling mill were reported by White (1904), Davis (1919), and Dyer (1945) and have been reviewed by Rose and Sullivan (1958). In these works, frictional force at the wall of the mill and between the colliding balls, and the interaction of different ball trajectories, was not considered. Moreover, it was assumed that the profile of the tumbling charge is independent of the degree of filling, which is generally not true. However, all this work led to the identification of so-called "equilibrium surface" which is the plane that separates the rotating charge into two regions. The inner region is static; here there is no motion relative to the mill shell. The other region is a shear region where either the balls flow down the surface of the charge (cascading motion), or are projected out of the surface and follow approximately parabolic paths (cataracting motion).

Jan 1, 1990

By W. K. Fletcher

As part of an ongoing programme on behaviour of heavy minerals In streams, the dispersion of Au as free gold (Day and Fletcher, 1987), Sn in cassiterite (Fletcher et al, 1987) and W in scheelite (Saxby and Fletcher, 1987) have been investigated downstream of mineralization. The studies of Au and W were undertaken, in British Columbia and the Yukon Territory, respectively, in streams that are strongly influenced by spring snowmelt floods. Sn was investigated under tropical rainforest conditions in Peninnsular Malaysia.

Jan 1, 1988

By C. Botha, M. J. Walls, C. T. O'Connor

The role of copper sulphate in the flotation of pyrite has been studied. A survey of a number of pyrite flotation plants using copper sulphate showed that in correct dosages, it was able to increase both grades and recoveries. This was confirmed in batch tests. Copper sulphate had no significant effect on the rate of adsorption of PNBX onto pyrite. Copper adsorbed irreversibly onto the pyrite when the latter was slurried in a copper sulphate solution. Copper sulphate had a significant effect on the maximum froth height obtained in static three-phase froth tests. Proposals to explain these observations are made.

Jan 1, 1998

By K. Oraee

A comprehensive, harmonic and sustainable development has always been a real concern of state policy makers. To reach such development, regional planning is an approach which is widely applied. This paper deals with policies adopted by a given country with rich mineral deposits, in order to accomplish a mining growth as well as economic development in relatively poor regions. In this regards, first, some worldwide experiences belonging to China, with large scale mining operations and Nigeria with a small scale mining industry, are studied. The mining industry in Iran is then considered as a case study. The study continues by categorizing and prioritizing Iranian regions based on their mining potential and the degree of development, using statistical analysis and Taxonomy and AHP techniques. Results obtained serve to provide recommendations as to where capital investments in the mining industry would produce highest returns. The approach used, together with the practical policies suggested in this paper, can be used to adapt appropriate strategies for mining development in a way that contributes to regional development and a more effective income distribution.

Jan 1, 2012

By M. Zuckerberg, E. Mader, R. Pasyar

We describe a new software product designed for the net present value optimization of multi-open-pit blended ore operations in which it is desired and/or necessary to dump some or all of the waste rock produced in the course of operations back into the voids created in the process of ore extraction. The software product simultaneously decides over the entire life-of-mine which material to mine in which year, once mined what to do with it, and where to put that material which it has decided to waste, all subject to annual blend and capacity constraints.

Jan 1, 2007

By David M. MacGillivray

1. INTRODUCTION The economic importance of bringing a new mine to production in the shortest possible time, is well known. In recent years the rate of escalation of mining costs has accelerated more rapidly than at any time in the past. This fact has enhanced the need to reduce time schedules and made it an overriding and predominant objective when planning new shafts. The squeezed profit margins and widely fluctuating metal prices have also increased the emphasis being placed on this aspect. Moreover the increase in the present value of future profits due to the reduction in the time element, can be so substantial that expenditure on equipment and additional labour can be justified conditional on sufficient gain in shaft sinking speed being achieved. The emphasis on time saving becomes more abundantly clear when considering the very large increase in the capital required to bring a modern underground mine to production. As an example, the initial capital expenditure requirements for a large new gold mine in the Western Transvaal, which has commenced production recently, is estimated at R200M, and a major extension to another deep level mine in the same area is estimated at R300M. With the uncertainty of future metal prices and the recent trends in increasing inflation, it is becoming more difficult than ever to estimate the profitability of proposed mining projects and any cost saving due to more rapid sinking of shafts can only assist in this respect. Since the shaft systems are frequently the most expensive set of underground excavations and no other underground work can commence until they are completed, the speed of shaft sinking is subject to closer scrutiny than in the past. In the following sections of this paper the factors contributing to the high average advance rates achieved by South African shaft sinkers are discussed. It is difficult, if not impossible, to estimate the effect of any single factor, in isolation, on the overall sinking achievements. However, the cumulative effect of improvements made in the inter-related activities is, probably, the most important contributor. Although there has not been any single major technical change or innovation to shaft sinking practices in the last decade, the average sinking speeds have increased, due to improved application and technical improvements in established procedures. 2. GENERAL When discussing South African shaft sinking techniques and average sinking rates compared to those achieved in other parts of the world, it should be remembered that the size and depth of South African shafts are often considerably greater than in most other countries. Typical examples of shafts either in the course of sinking or recently completed are -

Jan 1, 1979

By R. A. Jankowsi, S. K. Ruggieri

Airborne respirable dust levels on longwalls can be reduced if operators approach the dust control problem in a logical and fundamental manner. This can be accomplished through the proper application and continued use of effective dust control techniques. The Bureau of Mines is currently assessing the effectiveness of longwall dust control techniques in use today to provide mine operators with guidelines for selecting the most appropriate control technology. This paper presents a fundamental approach to the problem of shearer dust control. Three dust control techniques to be discussed are: deep cutting/increased pick penetration for reducing the amount of respirable dust generated; drum water sprays/improved water supply system to suppress the amount of airborne respirable dust; and improved external water spray system, the "shearer-clearer," to push the dust close to the face. The techniques have been evaluated in field trials and have been shown to be both practical and effective in applications to control shearer generated dust.

Jan 6, 1985

In the mining industry and in new and expanding fields, such as electronics, nucleonics, and astronautics, a new type of manager has evolved. The name most generally used is project manager. His business is to create a product and the principal means through which he accomplishes this is project management. In this chapter, new information is the product of the project manager; as such the products, for which the computer methods described throughout this volume are designed, fall in the domain of project management. It has been the author's experience that project management is the management tool to effectively direct the information technology function within an organization. The purpose of this chapter is to describe project management and to identify and present a solution to the problems associated with project management in the development and application of computer methods in a minerals environment. Specifically, the problems to be addressed will center around: (1) recognition of the need for project management in terms of business-environmental factors and product characteristics, (2) formulation of a method of operation in terms of organization and implementation, and (3) application of project management to the minerals industry.

Jan 1, 1979

By Richard Newcomb

It is four years since the seminal study of demand for rapid excavation by the National Academies of Sciences (NAS) and Engineering outlined this technology's opportunities, requirements and significance to the challenges of urbanization and natural resource conservation. The demand study was quite simple. Opportunities were valued at market while requirements to produce new technologies were valued at cost. The significance of new technology in economic terms was measured by the net discounted gains to users over time. The Academy view in 1968 was that these gains, even most modestly estimated, appeared large enough to justify the bill for research proposed by that Committee (1). In 1970 the question of demands became international in what is recognized as the first international experiment in technological policy analysis, terminating in the Advisory Conference on Tunneling of the Organization for Economic Cooperation and Development (OECD)(2). A monumental demand survey formed the basis for its economic assessment. The twenty-two OECD nations also made an impressive attempt to measure the magnitude of existing research and development efforts. In their recommendations periodical statistical demand forecasting and collection of demand data (Recommendation 1) was given central importance for public planning (Recommendation 2), the financing of public construction (Recommendation 3) and the encouragement of technological advance (Recommendation 4). Their program for international cooperation led to OECD's establishment of a Directorate for Environmental Affairs, and influenced the organization of the World Environmental Conference meetings now held in Stockholm under United Nations auspices. The OECD Conference was the first example of "an attempt to apply the concept of technological policy analysis to a 'civilian' technology having potentially

Jan 1, 1997

By M. M. Botz

Cyanidation tailings disposed of in a surface impoundment experience a loss of cyanide due to natural attenuation, which frequently reduces the cyanide concentration to very low levels. Quantifying cyanide losses in terms of impoundment geometry, local weather conditions and feed-solution chemistry has been largely empirical in spite of the fact that, in many cases, mining operations rely on surface impoundments to reduce cyanide to below an internally regulated concentration or below an effluent limitation. To permit a quantitative evaluation of cyanide losses in an impoundment, a computer simulation was developed to estimate the losses of free, weak acid dissociable (WAD) and total cyanide due to dissociation, photolysis and volatilization. Results of the model are compared with data collected for a North American tailings impoundment in 1998.

Jan 1, 2000

In September, a fleet of 363-t (400-st) Liebherr trucks became operational in Brazil and have already begun moving iron ore in Para state. Prior to the arrival of the the trucks the Brazilian fleet relied on trucks up to 218 t (240 st). With the addition of the 363 t (400 st) trucks, the fleet has since experienced the high productivity offered by Liebherr T 282 B trucks.

Jan 1, 2010

By Pasi Latva-Pukkila

Underground rock drilling has gone through intense development during the last 25 years. Mechanization and hydraulics have greatly increased the efficiency of drilling and improved the environment of the drill operator. As the total economy has become more and more important, the development has resulted in greater overall economy in drilling. The latest evolution step is computerization of drilling equipment. Computerization has been applied to tunnelling jumbos, long- hole drilling rigs and bolting rigs. With today's technology computerization is the natural way to increase capacity and productivity of the drilling process. However, it is still impractical to implement total "robotic" drilling. In computerized drilling the operator's role continues to be vital in controlling the drilling process and in analyzing the effect of individual parameters on the whole excavation process. Today this is called "CAD" - Computer Aided Drilling.

Jan 1, 1989

By R. F. Shurtz

This paper uses a simple model to illustrate the fact, widely known to information theorists, that the covariogram represents only half the information in the data used to construct it. It suggests and illustrates methods of putting the other half to use in describing mineral deposits. It also identifies applications in which the phase information is not needed.

Jan 1, 1986

By E. A. Metz

Ergonomics is the art and science that tries to understand the complex interrelationships among employees, their work environment, equipment, work methods and job demands. Coal and metal/nonmetal miners are exposed to a higher number of ergonomic risk factors than in non-mining occupations. In addition, studies have shown that these miners experience more degenerative disc disease and osteoarthritis than comparable industrial populations. A general discussion of the risk factors that cause overexertion injuries and disorders will be presented. In addition, the basic principles of ergonomics will be discussed with specific cases to show how successful programs have been developed. A successful ergonomics program should simultaneously improve health and enhance productivity.

Jan 1, 2002