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By Sandra L. Maxfield, Alan Mair

Strategic design of groundwater monitoring programs can increase public confidence in mine management, decrease financial assurance requirements, and minimize environmental budgets. Monitoring of inorganics is challenging because many occur naturally with baseline concentrations fluctuating spatially or temporally. Evaluating monitoring data to distinguish between a hazardous release or a natural fluctuation in baseline concentration can be controversial. In order to develop an effective program, monitoring parameters should be selected which are mobile and stable. Statistical procedures should be customized to address the uniqueness of groundwater systems. Calculated baseline concentrations should minimize the false negative & false positive rate.

Jan 1, 1995

By Milton H. Ward

The percentage of exploration dollars flowing out of the industrialized countries continues at an all-time high, and this shift in risk money is justified (Samuels, 1990; Bosson, 1977). Clearly, the odds of discovery are greatly enhanced if exploration is pursued in an untrampled and geologically more prospective environment. Unfortunately, such major unexplored areas of the developed world are shrinking rapidly, not just because the lands have already been tested, but primarily because they have been withdrawn from exploration. Experience, however, has shown that foreign investment is not without risks. These include problems that result from working in isolated areas, a lack of infrastructure, untrained workers and an absence of a solid geological data base. While the likelihood of once-feared expropriation is now low, mining enterprises still must take precautions to gain the support of their constituencies, including a variety of governments (local, provincial and central), workers, environmentalists, cultural organizations and local landowners. Is foreign exploration worth the risk? In most cases, Yes! But maintaining tenure and long-term success in a less developed country is only likely with good planning and the use of appropriate safeguards. These include measures such as buying country-risk insurance, building multinational relationships, forming joint investments, developing a broad customer base and seeking local investors in the company (Cobbe, 1979). The primary theme of this lecture is: How a company handles its constituency is critical to long-term tenure in a foreign country. Ideally, a multinational mining company would be so effective in dealing with the local people and managing its relationship with the host government that it would become a preferred employer, preferred over its competitors and over local companies. Historical overview Our earliest ancestors lived in Africa three to four million years ago. The Paleolithic or Old Stone Age, about 500,000 years ago, marked the beginning of mining in its earliest form (Gregory, 1980; Wolf, 1984). Various types of rocks and stones were used for tools and weapons, with flint being the preferred resource for implements. Initially, these materials were collected as stones (eoliths) lying on the surface. Then they came from excavations of flint in limestone beds that were exposed in river banks or naturally occurring excavations. Later, more formal mining developed. No doubt tribes of the Old Stone Age experienced conflict over rights to eoliths, food and land. The question of who owns the land and has rights to its contents and what is fair value for extraction is still the subject of intense debate and, occasionally, open conflict. As time passed, the search for useful minerals required migration from one area to another. Later, voyages from Europe to the New World and travels to other remote regions were funded and supported by absentee investors, kings and such (Rogers, 1976). The primary objective of such funding was to obtain gold, silver, food stuffs and other commodities that could be collected from the new countries. This is still the objective of foreign investment.

Jan 1, 1994

By M. Georgescu

In the framework of the rapid development of contemporary society, the use of underground space represents an emerging opportunity because it can contribute to decreasing pressure of occupation of ground space while in the same time it can increase the economic value of the useful mineral substances, also through underground establishment of dangerous surface activities, contributing thus in environmental protection. This paper underlines the most important benefits of underground space utilization with the objective the exploit the potential of this real resource.

Jan 1, 2006

By R. Hogg, A. C. Maffei, D. T. Ray

Based on standard population balance models for agglomeration and size reduction processes, a simplified model has been developed to describe simultaneous growth and breakage in the flocculation of agitated suspensions. The results of semi-batch flocculation tests have been used for estimation of the model parameters and empirical relationships have been obtained to describe the effects of process variables and to establish scale-up criteria. Application of the model to the design, operation and control of continuous flocculation processes is discussed.

Jan 1, 1990

By J. C. Stankus, S. S. Peng

Many coal seams are associated with soft floor strata. During mine development, if coal pillars are not properly designed, floor heave occurs and causes interruption of coal production. In the severe cases, the section or mine is abandoned. One method for controlling floor heave is floor bolting. This paper describes the demonstration of flour bolting methods in a West Virginia, info coal mine. Three methods were used: vertical full resin bolting, floor truss bolting and floor truss bolting pins a floor slot at the center of the entry. The design of each method and the experimental results are discussed.

Jan 1, 1995

By Raj K. Rajamani, Ilesh M. Shah

Maintaining pH, a routine requirement in many industrial processes, is by no means trivial. The control is troublesome because of the inherent nonlinearity and frequently changing process dynamics. Many researchers in the past have investigated advanced on-line estimation and/or adaptive control techniques to overcome these difficulties. Most methods require the development of a complex mathematical model. The present work deals with the use of a simple and elegant method for pH control, based on the use of fuzzy logic. First, a standard fuzzy-logic controller is discussed, followed by a self-organizing controller. The latter algorithm generates a set of rules based on observation of the process. Thus it is a learning algorithm. The development and application of the algorithms to a laboratory acid-base neutralization experiment are presented. This elegant technique is powerful and deserves attention in mineral pro- cessing.

Jan 1, 1990

By Vincent J. Murphy

INTRODUCTION Geophysical applications to engineering projects are usually considered for reconnaissance exploration, and for some preliminary design phases. Recent experience indicates a growing need and a greater number of requests for measurements during construction. This is particularly true where seismic velocity values are related to strength properties of rock. Typical project objectives during construction are: dike and tunnel realignments required by surprise conditions encountered during foundation preparation; checks on grouting effectiveness which require velocity measurements before and after grouting; and dynamic moduli measurements along the walls of tunnels and deep excavations. This paper considers one of the on-site seismic applications that is rather simple and straightforward, and yet has few references in the literature. The specific objective is the measurement of seismic velocities (both "P" waves and "S" waves) for determining the thicknesses and dynamic moduli values of loosened zones of tunnel wall rock. PRE-EXCAVATION SEISMIC METHODS The seismic methods suitable for engineering project studies are well known and especially suited for routine site reconnaissance; these are illustrated in Fig. 1. The seismic refraction profile with a

Jan 1, 1997

By R. D. Miller, L. Schulte, J. Davenport, D. W. Steeples

Shallow seismic reflection methods were successfully used to delineate the subsurface extent of roof failure associated with the dissolution mining of a 120-m (400 ft) deep and 60-m (200ft) thick salt bed in central Kansas. Surface subsidence at North American Salt's Hutchinson, KS, salt-dissolution well field represents a potential risk to surface structures and transportation facilities. Three intersecting common depth point (CDP) seismic reflection profiles, targeting the subsurface around an actively subsiding sinkhole, possess sufficient resolution to delineate the horizontal and vertical extent of subsurface rock failure associated with the subsidence. The three seismic profiles showed a disturbed subsurface area 90 to 105 m-diam (300 to 350 ft-diam) at a depth of between 60 to 75 m (200 ft and 250 ft). Confirmation drilling verified the interpretation of the seismic data. The seismic reflection method has the potential to resolve disturbed subsurface areas greater than 23 m-diam (75 ft-diam) at this site.

Jan 1, 1994

By A. K. Sinha

Inspite of the growing demands worldwide, thermal coal must compete in the market both in price and quality. The design and performance efficiency of coal preparation plants is thus crucial to the survival and profitability of a coal industry. While the coal recovery influences the cost of production, the quality produced by a preparation plant determines the selling price. Several coal preparation plant simulation models have been developed in recent years to help Improve the performance of coal preparation plants. A research project was recently conducted at Southern Illinois University to evaluate the practical applicability of such a model. The results of this study are presented and discussed.

Jan 1, 1986

By Mark Leggett, Kevin Roberts

The need to modernise and increase the safety provision of older road tunnels raises challenges in maintaining the operation of the tunnel during such improvement works. The Mersey Kingsway twin road tunnels located in Liverpool UK, constructed in the late 1960s, have had three new cross passages constructed to allow emergency evacuation from one tunnel to the other tunnel and provide safer access for emergency services. The 3200m long road tunnels are lined with an unusual reinforced concrete steel-faced segmental lining with a paint finish. Construction of the cross passages occurred during night possessions with the tunnels returned to normal operation during the daytime. Constructed through water bearing sandstone and lined with precast concrete segments, the passages required advance ground treatment and support works. This paper presents the historical background to the Mersey Tunnels and describes the procurement strategy, design and construction approach adopted for these important safety improvements.

Jan 1, 2003

? The U.S. depends on minerals for economic growth and development, and for national security and defense. ? Public lands are an important, long-term source of essential minerals. ? Access to public lands for mineral exploration and development has become more difficult as large tracts of land have been designated for other uses. ? Mineral-bearing areas on public lands are routinely withdrawn or restricted from development before comprehensive resource inventories and economic assessments have been made.

Jan 1, 2011

By B. Govindarajan, T. C. Rao, J. P. Barnwal

A simple modelling methodology has been proposed to predict the performance of industrial coal flotation circuit based on the observations made on the actual performance. The solid content in the tailings of the coal flotation circuit has been identified as a lode-star to predict the performance in terms of yield and ash content of the concentrate. The modelling parameters are directly measurable.

Jan 1, 1995

By John F. Spisak

Versatile living organisms, historically exploited as functionaries in the food processing, pharmaceutical and chemical industries, have not been successful in achieving similar or significant acceptance within the minerals industry. The current biotechnical revolution coupled with its expanded understanding, dictate that a flagging minerals industry reconsider the use of biotechnology in metallurgical applications. Living resources, either singly, in commensal association or in complex communities, are capable of duplicating fully integrated and complex processing functions. Organisms can mine and extract metals, detoxify chemical effluents and synthetically produce compounds. They have been criticized as exhibiting poor kinetics, excessive energy consumption and environmental sensitivity. However, expanding knowledge reveals that these organisms are surprisingly adaptable, variable and extremely durable. Applied biotechnology in specific cases offers favorable economic returns, environmental benefits and aesthetic value. Selective implementation of living systems can offer opportunities for reduced labor, increased productivity and technological advance. Success will not come easily. Capital must be risked, controversial decisions made and new ground plowed. Traditional, specialist thinkers will of necessity give way to interdisciplinary expertise and unorthodox methodology if success is to be achieved. Those who vigorously persevere, however, are likely to be rewarded with a dynamic and profitable new role in a restructured minerals industry.

Jan 1, 1985

By A. W. Khair

This paper presents an assessment of modeling techniques in predicting subsidence over longwall areas. Extensive instrumentation, both at the surface and subsurface of three longwall mines in northern West Virginia have been made. Ground movements were monitored during" a three year-period until subsidence ceased in these areas. A comparative analysis of empirical subsidence prediction techniques including, graphical {NCB}, profile function, influence functions (USBM, BAL'S, KNOTHE'S, and zone area) will be presented. A brief geologic and topographic description of each site along with the instrumentation and monitoring program will also be presented.

Jan 1, 1989

By Ch. Roumpos

The present contribution investigates the way of applying benchmarking for large-scale open-pit mining operations based on sustainability indicators proposed by numerous institutions or groups of experts. These indicators have been developed taking into consideration the legal and regulatory framework that are in force. However, their scope is not only to declare the mining company?s compliance with all legal requirements but also to represent its economic, environmental, and social performance. In this way, sustainability indicators allow assessment of a company?s capacity to produce commodities, to meet the environmental quality requirements and to contribute to a long-term economic, cultural and social development of the local communities.

Jan 1, 2007

By Ted M. Noskiewicz, James A. Ramsay

INTRODUCTION During the various stages of an underground project from inception through design and construction, probably the single factor of most interest and concern is the nature of the ground. The ground conditions more than any other item govern costs and feasibility; and although the methods available for assessing the ground have become increasingly reliable during the past thirty years, it is still very difficult in many cases to predict the behaviour of soil and rock during and after excavation. To help in this ground evaluation process, we have frequently supplemented the boring program with one or more large diameter inspection holes; and during the past eighteen years, seventeen of these holes have been constructed on tunnel projects which we have designed. There are references in the literature to similar inspection holes (1); however, as far as we are aware, no detailed description of them has been published. The behaviour of soil or rock during and after excavation and the effect of ground water on tunneling operations are of vital interest to tunnel designers and contractors. A comprehensive geotechnical investigation is therefore among the early and most important tasks carried out on a tunnel project and the backbone of every geotechnical investigation is the boring program. A series of borings, typically 50 to 100 mm (21 to 4 in) diameter, are drilled from which soil samples or rock core are recovered and the ground water observed.

Jan 1, 1979

By Frank T. Wheby, Edward M. Cikanek

A computer performs all logic and computations customarily done by hand in preparation of engineers' estimates or contractors' bids on tunnel-shaft systems. The program described is based on construction methods, work forces and equipment selections corresponding to the current state-of-the-art of rock, soft ground and cut-and-cover tunneling. The program contains logic to permit estimates of cost of complicated tunnel-shaft systems; it is not necessary to input quantities, as the program calculates those from the tunnel design that is internally generated. In any estimate, the program bases its cost computation on user-input requirements and site conditions, such as tunnel shape and size, shaft depth, ground characteristics, construction methods, and other factors. To provide great flexibility, the user of the program is provided with options for accepting designs built into the program or overriding these designs by his own inputs. An illustrative example is presented.

Jan 1, 1974

By N. S. Dalal, V. Castranova, K. Van Dyke, V. Vallyathan, J. H. Kang

Previously we reported crushing or grinding crystalline silica results in silica-based free radicals on the particulate surface which can generate hydroxyl radicals in aqueous solution (1). Now we find that freshly ground silica is more cytotoxic to and a more potent activator of alveolar macrophages than similarly sized aged silica. Since the United States Department of Labor estimates that over 1.25 million American workers may be exposed to freshly ground crystalline silica arid nearly 60,000 may be at risk of developing some degree of silica-based occupational lung disease, then this is hardly a trivial problem. Occupations of concern include workers who come in contact with silica including miners of soft and hard minerals, stone quarry workers, glass workers and even millers who stone grind flour. Acute silicosis is manifested by inflammation, alveolar lipo-proteinosis, and the rapid development of respiratory disability that depending on the dose of silica can produce chronic silicosis which takes 20 - 40 years to develop. It is demonstrated by the appearance of concentric hyalinized nodular lesions and progressive development of dyspnea(3). Certainly the free radicals produced on the surface of freshly ground crystalline silica play a most important role in producing the acute and chronic symptoms of silicosis. When respirable-size freshly- ground silica (0.1 -- 5 microns in diameter) enters the deep alveolar spaces in the lung and contacts an aqueous environment, hydroxyl radical are generated and cellular damage is bound to occur. We have found that freshly ground silica can cause lipid peroxidation and lysis of erythrocytes(1). The objective of this investigation was to further elucidate the enhanced toxicity of freshly ground versus aged silica. It can be deduced from the data that not only is freshly ground silica more cytotoxic to alveolar macrophages but it is a more potent stimulant of these phagocytes. However the mere characterization of toxicity is not entirely helpful if there is not a useful means to detoxify the cause of the damage. We have identified an aqueously soluble substance that can be used in high dilution to detoxify the SiO(•) and Si(•) type of free radicals. This is the organosilane known as Prosil 28 (R). We have found that coating of the freshly ground silica can effectively reduce its toxicity. The importance of this observation is that such a coating could be used with water cooled drills. This may partially detoxify silica at the point of generation of the free radical, i.e., the generation of the fresh silica dust itself. Such a coating could be used in great dilution 1:103 or 1:104. The coating would be long lasting, inexpensive and should be non-toxic because of the great dilution.

Jan 1, 1991

By G. H. Lewis, C. L. Krcil, N. S. Harding, D. E. Havekotte

INTRODUCTION Limestone injection work was completed in a 440-kW (1.5-million Btu per hour) pilot-scale combustor in preparation for a 50,000-kg/h (110,000-lb per hour) industrial steam boiler limestone injection test program. The main objectives were to: (1) identify the important variables that affect sulfur capture, (2) determine the maximum SO2 removal, and (3) determine the effect of limestone addition on furnace operability and heat transfer. A more detailed report is given by Lewis et al. (1985). The test program was divided into two phases. The objectives of Phase I were to determine the important variables that affect SO2 reduction and to investigate the effect of limestone addition on combustor operation and heat transfer surfaces. The objective of Phase II was to determine, using only the important variables identified during Phase I, the conditions that resulted in the greatest sulfur dioxide reduction. Phase I Test program Using one limestone, five variables were identified as having an effect on SO2 reduction. These are noted with their respective ranges: heat release rate [103 to 166 kW/m3 (10,000 to 16,000 Btu per hour-cu ft)], Ca/S molar ratio (0 to 3), flue gas oxygen concentration (3% to 5%), additive particle size [90% -150 µm (-100 mesh) and 90% -45 µm (-325 mesh)], and burner stoichiometry (SR = 0.75 and >1.15). A 2.3% sulfur northern West Virginia coal, pulverized to a nominal grind of 70% -75 µm (-200 mesh), was burned for the tests. The limestone used was obtained from a Maysville, KY, quarry and contained 51.75% (wt) CaO. An 11-run statistically designed program (plus three duplicates) was used to screen the five variables. The effect of limestone injection on the combustor heat transfer surfaces was determined by comparing the heat transfer rates through a slag panel and fouling probes during periods with and without limestone injection. Combustor operation was determined by noting any operating problems that occurred during the tests. Test procedure After furnace wall temperatures had stabilized at operating conditions, heat transfer surfaces (slag panel and fouling probes) and the convection section were blown clean, and a four-hour test was begun. The

Jan 1, 1987

By Paul F. Thiele

The mining industry of Georgia, while not as large as in some other states, is still an important part of the economy. Total value of mineral production in 1966 was $148.6 million.l/ Clays and stone produced the most income, Other minerals included sand and gravel, iron ore, mica, talc, barite, bauxite, cement, feldspar, kyanite, peat, and rare-earth metals, titanium and zircon concentrates. Georgia ranks first among the states in production of kaolin, second in fuller's earth and rare-earth concentrates, third in bauxite and kyanite, fourth in barite and ilmenite, and fifth in feldspar. It is quite likely that phosphates will one day be mined in the south eastern part: of the state, and that alumina will be produced from the extensive kaolin deposits in the central part of the state.

Jan 1, 1968