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By R. S. Hearon

The image of the open-pit miner in the eyes or the Environmentalist has never been very outstanding. The phosphate industry, whose history in Florida reaches back to the late 1800's, can-not be credited until recently with a large number or accomplishments in terms of protection or the environment to change this image. This lack of action was not deliberate or in opposition with the desires of the public. In the formative years, there was little or no public and the companies found it necessary to build towns to house their employees and their families, towns which remained in existence until the late 50's and early 60's or formed the core of present large communities. Neither these pioneers nor most subsequent resource developers considered themselves un-thinking spoilers, nor were they so regarded by their contemporaries. Instead, they acted in a manner consistent with their environmental circumstances and intellectual heritage. Early Americans did make mistakes in using the land but the mistakes became apparent only in the opinion of later generations. Over the past five to ten years, there has been a new self-awareness in the industry with regard to environmental responsibilities brought about, in part by a continuing onslaught of new regulations with jurisdiction over our activities. Part of the new regulations are aimed at industries as a whole while many, particularly state regulations, pertain specifically to the phosphate mining industry. Why all the new regulations? The reasons are encased in a complex web of activity but stem primarily from a new public awareness of its environment. More and more of our youth have become interested in the environmental science areas such as biology and ecology. The tremendous growth rate in both the population and industry has made personal issues out of subjects such as atmospheric inversions and water shortages which previously were abstract concepts. The State has grown from a population of 1,500,000 in 1930 to approximately 9,000,000 people today. This personal impact and general lack of knowledge on the part of the public concerning economics has resulted in big business no longer being held in awe, often in contempt and generally in suspicion where environmental concerns are encountered.

Jan 1, 1978

By F. Habashi

The changes that took place in China between 1984 and 2004 are remarkable. Visits were made to universities, research institutes, metallurgical industry, and many cultural centers within five trips during this twenty years period. The impressions of these visits are outlined.

Jan 1, 2007

By Yang Zhao, Wanping Wang, Siqing Liu, Shuming Wen

"In China, most reserves of rich iron ores have now been depleted and sustainable development of low-grade iron ores has become a critical discussion topic in the mining industry today. The aim of this study was to evaluate the applicability of beneficiating a low-grade, hematite-magnetite ore (assaying 18.64% Fe) for subsequent utilization. In this study, process mineralogy and beneficiation of the ore were carried out in the laboratory. First, mineralogical investigation shows that the main metal minerals are hematite, magnetite and a little octahedrite that cannot be used at present, and the main gangue minerals include albite, quartz and ankerite. Based on the above, a combined process of magnetic separation and gravity concentration has been developed by using laboratory low- and high- intensity magnetic separators and a slimes shaking table, respectively. Factors affecting these separation methods are discussed, including process mineralogy on the tailings of the high-intensity separator, where the iron minerals were found to be finely disseminated in the gangue as inclusions. By applying a two-stage grinding step and a magnetic separation stage together with gravity concentration, a marketable iron concentrate assaying 60.79% Fe at a recovery of 60.23% can be obtained, when the feed assays 18.75%Fe, which provides some useful information for the sustainable use of low-grade iron ore.IntroductionIron is the world’s most commonly used metal. Steel, of which iron ore is the key ingredient, represents almost 95% of all metal used per year, primarily in structural engineering applications and for maritime purposes, automobiles and general industrial applications. By the end of 2009, the iron and steel production in China ranked the first in the world, and reached 0.567 and 0.537 billion tons, respectively. The domestic supply of iron ore was 0.88 billion tons and about 0.628 billion tons of iron ore were imported in 2009."

Jan 1, 2015

By V. L. Brant

The estimated total energy demand for the U. S. is 60 quadrillion BTU for 1970 and is expected to more than double by the year 2000. Today the energy crunch is here. It is evidenced by brownouts to conserve electrical energy, and the shortage of gas and oil. Many such headlines, including suggestions for energy rationing, are in the news today. Paradoxically we have an abun¬dant source of energy in the form of coal. Energy consumers, however, are geared to use fuel in other forms. It is the intent of this presentation to discuss processes under development for conversion of the energy contained in these vast coal reserves to more usable forms. Coal conversion to synthetic fuels should be of particular interest to those engaged in mining. Coal consumption in a single conversion plant is expected to range from 10,000 to 40,000 tons per day. Plants will be located at the mine mouth and will operate continuously 24 hours per day, seven days per week. Further, many such plants will be needed., For example, looking at natural gas only, the supply/demand gap is estimated to reach 13 trillion cubic feet per year by 1985. Assuming that gas from coal conversion were to fill only 101, of this gap, 15 plants producing 250 MMSCFD would be required. These plants would consume about 90 million T/Y of coal or 135 million T/Y of lignite. It will indeed be a challenge to mine, suitably prepare, and transport coal at these projected volumes without interruption. Many ideas have been conceived for better utilization of coal and these are in various stages of development. Those supported by public money are covered by the Annual Report of the Office of Coal Research (OCR), Department of Interior. The two processes to be discussed, the Consolidation Coal Company's (Consol) C02 Acceptor Process (1)(2)(3) and The Pittsburg and Midway Coal Mining Company's (PAMCO) Solvent Refined Coal Process (4)(5) are both sponsored by OCR.

Jan 1, 1970

By Michael Murphy, Mark Van Dyke, VASU GANGRADE, Brent Slaker

Room-and-pillar mining in multi-level underground stone mines come with unique pillar stability issues. The pillar stability in these mines primarily depends on the thickness of interburden between mining levels and the staggering of pillars. NIOSH has previously established pillar design guidelines for shallow, flat-lying mines and single-level operations, but there is little guidance for ground control design in multiple-level stone mines. Therefore, to improve the overall understanding of ground control in these mines, a microseismic monitoring system has been installed at a multi-level underground stone mine in Tennessee with up to a 243-m overburden and a 7-m interburden thickness between levels. The microseismic system is comprised of nine uniaxial accelerometers and one triaxial accelerometer installed in the interburden. The seismic array is locally focused with all sensors installed within a 625 m2 area and is setup to monitor the seismicity around the formation of the pillar in the lower mining level. Data is collected over 11 months and comprises of over 1,000 high-confidence events that have been located in the study area comprised of post-blast activity. The event locations were identified using a 3D-velocity model, with an average 4-m location accuracy for this array calculated using the system data. Most observed seismicity was on the excavation boundary, both in the interburden and in the roof of the top level. At this stage of analysis, there are no significant rock failures with which to correlate seismicity, but event locations correlate well with presumed damage in the vicinity of blasts.

Apr 26, 2022

By S. Nygren

Nalco Chemical Company and a North Carolina Phosphate operation have formed a successful supplier/customer team effort that has resulted in major improvements in the operation of the clay thickening circuit at the Aurora, North Carolina concentrator. A Nalco OPTICUS® Automated Process Control System for thickener and flocculant control was installed in 1994. The paper will discuss in detail the development and refinement of the OPTICUS system over the past three years. The paper will survey the development and networking of process control for monitoring, controlling and operating four 325-foot Dorr-Oliver thickeners, three 80-foot high-rate Enviro-Clear thickeners and control links to the facility's clay/gypsum blending operation.

Jan 1, 1998

By Samuel A. Reipas

Introduction The ore mining industry has been successful because of technological progress and huge sums of capital investment. But new technology and plants have not come cheap. The problem now is companies will run out of money before they run out of ideas. Survival Strategies Industry survival strategies demand restructuring and new plans. Inland's prescription for the future includes: • Continued emphasis on technological improvements to upgrade pellet quality and lower costs; • Effective use of human resources resulting in employee satisfaction and improved planning and productivity; • Deliberate, well planned, and documented cost-control programs for the short- and long-term; and • Capital investments to support the first three initiatives. Technology Technological changes are not only required by the need for operational improvements, but by product quality improvement dictated by the user - usually the blast furnace operator. Established ambient measurements of pellet quality, such as tumble index, compression strength, porosity, size distribution, and chemical composition, are no longer considered meaningful in predicting pellet performance in a blast furnace. New specifications, called low temperature and intermediate temperature properties, have been recently introduced. Low temperature specifications are characterized by disintegration of pellets in the 500°C (930°F) range in the upper portion of the granular zone during the hematite-to-magnetite transformation in blast furnace stack. Intermediate temperature properties (measured by 1000°C or 1800°F) are characterized by swelling, reducibility, and compression strength after reduction, reflecting conditions in the lower portion of the granular zone of the furnace. These new parameters are being used for pellet quality evaluation at Inland, and will be introduced at its Minorca mine for more routine analysis and correlation with the pellet furnace operation. With increased emphasis on quality, effective communication between the blast furnace operator, research, and the pellet plant operator is critical. At Inland, this is accomplished through technical meetings where the opportunity is provided to solve problems, establish a common understanding on the value of quality, and develop future quality standards and programs. With the degree of sophistication in determining pellet quality as it affects blast furnace operation, the future pellet plant operator will actually be producing a custom pellet. Human Resources Technological change has been a strong point at Inland, and will continue to be. However, human resource management is equally important. Is management giving sufficient attention to employee motivation and involvement? It is a way to improve productivity, reduce costs, and enhance employee job satisfaction. The industry is beginning to understand the principles and the potential for tapping employee brainpower. The payoff can be handsome. Management has to be willing to share both information and power if participative management is to live up to its potential. It has to become more flexible and be willing to adapt to change on the human side. Management should embrace rather than fear employee involvement. Given time, joint problem solving will replace adversarial attitudes and pay dividends for both sides. Productivity and product quality will improve and new dimensions of employee job satisfaction will be achieved. But, it will not happen overnight. Attitudinal change must permeate the organization from top to bottom. This change is needed to support the working relationships and give everyone a sense of direct and meaningful involvement.

Jan 11, 1983

By Jonathan Taylor, Irwan Halim, Frederick (Rick) Vincent

The new underground facilities for the LINAC Coherent Light Source project at the Stanford Linear Accelerator Center in Menlo Park, CA, are constructed in very weak sedimentary rock interspersed with uncemented zones. In addition to several 21-footwide (excavated) tunnels, the NATM excavations include a large, 49-foot wide (excavated) cavern, an unprecedented size in this geology. The critical design issues include characterization of the weak rock, some shallow rock cover areas, and very stringent criteria for final invert slab movements within the tunnel. The design also incorporated severe seismic criteria, since the site is in close proximity to the San Andreas Fault.

Jan 1, 2007

By L. J. Altenburg

There are a lot of key factors involved in achieving a successful Safety Program. I would like to discuss some of these factors and how they have played a major part in our success at Jacobs Ranch Mine. The areas I will cover concern: 1) Facility Standards (Corporate/Minesite), 2) Communication (Employee/Management -"Teamwork"). 3) Proper Training (Employee/Management). 4) Employee Attitude. 5) Incentive Programs. 6) Health Programs. 7) Results/Benefits.

Jan 1, 1994

By Joe Roby

Rolling disc cutters are the business end of hard-rock and mixed-face tunnel boring machines (TBMs). Since their first successful employment on a TBM more than 50 years ago, disc cutter technology has constantly evolved, allowing modern TBMs to excavate very hard and abrasive rock efficiently. Disc cutters have also been employed successfully on earth pressure balance (EPB) and slurry machines, cutting rock under water and ground pressure. The range of materials excavated by machines today is broader, excavation rates are higher and cutter costs are lower than ever before, proving the value of investment in cutter development. Disc cutters are used on a range of tunneling equipment, from pipe jacked slurry micro-TBMs less than 1 m (3.3 ft) in diameter to 15 m (49 ft) in diameter, hard-rock boring TBMs. The geological conditions under which they are employed range from sands and gravels, with several bar of water pressure, to extremely hard, massive rock with UCS up to 420 MPa. Regardless of the type of machine or geology, one thing remains constant: changing worn out cutters is costly. When cutters must be changed in the middle of a tunnel, the contractor incurs the cost of downtime as well as the cost of refurbishing or replacing the cutters. In the case of catastrophic cutter failures, the project can be stopped completely for long periods, and the costs mount up rapidly while tunnel production is at a stand still. Catastrophic cutter failures include the occasion when hard-rock disc cutters are failed in groups (called a ?wipeout? phenomenon) and the operator fails to stop the machine, which results in severe damage to the cutterhead. The cause of this can be either an undetected failed cutter propagating damage to surrounding cutters or operator error in steering. Regardless of the cause, the resulting damage can take days or even weeks to repair. When cutters fail prematurely on EPB or slurry machines in certain geological conditions, it is impossible to evacuate the chamber and, therefore, impossible to get [ ] into the chamber to change the cutters. The solution is frequently an unplanned intervention shaft that must be sunk at great cost. The importance of being able to predict cutter life accurately, and in all geological conditions, cannot be overemphasized. For these reasons, cutters have been developed for specific machine types and sizes, as well as for specific geological operating conditions. Different size cutters are required for different size machines. For example, while 483- and 508-mm (19- and 20-in.) cutters are used on large diameter TBMs, it is impossible to employ cutters so large on a small micro-TBM. Also, the cutter must be designed for the specific geological conditions under which it will be operating. The disc cutter rings required to bore extremely hard rock are the most expensive of cutter rings. However, they provide little advantage in weaker rock formations where less expensive rings will do the job as well. It is important to choose the correct cutter for the machine and the geological conditions in order to get the best balance of cost and risk.

Jan 1, 2009

By Bryson D. Trexler

Man's activity in developing, operating, and abandoning a mine often affects the quality of the ground water and surface water. Acid water drainage from mines is an example of an impact from mining that results in degradation of ground and surface water. New flow systems are created by the mining activity. The mining made possible complex chemical reactions that, with water movement, create a discharge of low pH, poor quality water. Remedies for these problems fall into two general solutions: 1) treatment of the end product and 2) reversal of some aspect of man's disturbance of the natural system. The relative reversibility of various aspects of man's impact from mining activities ranges from relatively easy to very difficult, from economically feasible to economically infeasible, and from technically possible to essentially impossible with present knowledge. The relative reversibility of a mine-related problem cannot be assessed without first understanding the detailed physical interactions that combine to form the problem. Acid water drainage is a combination of the availability of several chemical factors with the availability of water for a transport mechanism.

Jan 1, 1982

By D. Rutledge

Discrete (digital) signal processing techniques are proving to be very valuable tools for miners using the block cave method. Waveform analysis of different measured signals associated with active mining provides valuable information on production dynamics and safe operation of the mine. For example, correlation of the three-dimensional surface displacement velocity waveform and the production output waveform reveals a remarkably predictable time-varying physical process. In this paper, the authors discuss the signal processing techniques used to study these relationships, as well as the related implications for mining.

Jan 1, 2008

By Robert D. Brown, Charles A. Sorrell

The decade of the 1980's saw "advanced materials" become a key factor among the industrialized nations, with the United States, Japan, and the European Economic Community being the major competitors. All three have identified communications technology, advanced materials, and biotechnology as the keys to future industrial leadership and the closing decade of the 20th Century is expected to be an era of rapid development and restructuring. The progress of EC'92, the effort to develop uniform standards and remove trade barriers in Europe; the determination of Japan to commercialize advanced structural ceramics, alloys, composites, and superconductors; and the emergence of less developed countries as major supplies of commodity materials pose enormous challenges to the position of the United States as an industrial and financial leader. A consensus is developing that the industries that are first to commercialize the large array of new structural materials and electronic, optical, and magnetic materials and devices will be those who determine the structure of national and world economics. Many technical, economic, legal, political, social, and cultural factors are important determinants in the race to commercialize new materials. Millions of words have been written about these factors and their interdependence; yet the sheer complexity of the problems, the rate at which changes are taking place, and the economic risks involved are so great that government policy makers and industrial decision makers find adequate understanding to be very difficult. Of the many factors involved in advanced materials, the Bureau of Mines has the statutory responsibility to provide information on where materials can be found and how they are mined, extracted, purified, combined, and recycled. It is obvious that minerals availability is essential to implementation of any new technology just as there can be no commodity metals industry if the ores are not available. Because "minerals availability" for commercialization of advanced materials and devices is more complex than for commodity materials and a new mix of materials and processes is emerging, the Information and Analysis Directorate of the Bureau of Mines is redirecting resources to provide reliable information for policy and decision making. The Office of Advanced Materials Coordination (OAMC) was established as a staff operation in July 1987 to assist the efforts of the divisions and branches. The key issues and problems were defined and the role of the Bureau was outlined (Sorrell, 1987, 1988). In February 1990, the functions of OAMC were transferred to the new Branch of Advanced Materials, a line organization parallel with the Branches of Ferrous, Nonferrous, and Industrial Minerals, and was given the responsibility for developing new methods to acquire, analyze, and disseminate information about new materials. The purpose of this paper is to provide definitions, a summary of major issues and problems, an overview of minerals and processing availability problems, and a perspective of the ways in which the mining and materials industries can help to ensure domestic availability of raw and processed materials.

Jan 1, 1990

By Z. Scopa, E. Tarshizi, R. Setterlind, L. Frost, R. Livernois

"THE MINES OF THE FUTURE The mines of the future present a host of challenges, which may appear exciting or daunting depending on one’s perspective. Whether some sectors of the public recognize it or not, the demand for raw resources is not going away any time soon. In fact, it is rising as global population grows, urbanizes and attempts to steadily increase quality of life. Yes, at the same time that much of the highly developed world is calling for greener goods, reduced consumption, and cleaner production, in other areas there are cries for clean water and sanitation, consistent energy supply, access to health care and education, personal security, and support for basic human rights. The balancing act for sustainable development of our global society is indeed precarious, and the mining community is necessarily a key player. Fortunately, many industry members have accepted this role and the responsibility to provide leadership and a solid foundation for progress. Looking ahead, we need new generations of leaders, many of whom will be mine engineers, which are ready to tackle all sorts of complex problems. There are tremendous needs just for technological innovations. Increasingly tough deposits will require that we continue to expand scale toward “super” pits and “deep” underground mining fully develop unconventional recovery techniques like in-situ leaching and gasification or deep-sea extraction, and seriously consider off-earth endeavors. Such work will take entirely autonomous equipment; novel separations, processing and recycling methods; and systems that can withstand extreme physical conditions – just to name a few. It will also take a level of systems integration never-before seen in our field, complete with big data issues, sophisticated analytics and modeling efforts, and cyber-security challenges. Moreover, increasingly complex environmental problems will require creative solutions. Addressing issues like pollution control across multiple media, emerging contaminants, optimal management of wastes, selective mining, and shared use of resources between mine operations and surrounding communities and ecosystems are among top priorities. Really, a complete paradigm shift must occur, such that our focus is on overall improvement of environmental conditions, rather than minimization of impacts. A similar shift will be required in the social realm. How can we make miners safer and healthier on-site and off? How can we contribute to communities such that they are better off, now and long-term, for having a mine next door? How can we help transform artisanal mining practices to also contribute to sustainable development? How can our work be a factor in increasing economic and political stability? How can we improve the public understanding of raw resources and the need for mining enterprises?"

Jan 1, 2017

By H. EI-shall

Bench top centrifuge is used to study the consolidation behavior of phosphatic clays. A mathematical model (based on first order kinetics) is developed to describe the relationship between the void ratio (at any time) and the effective stress. Permeability of the sediment as a function of the void ratio is also described. The obtained data are compared with that obtained by other consolidation testing methods. Centrifuge results indicate that consolidation data may be developed in a short period of time (hours) as compared to days or weeks when other techniques are used.

Jan 1, 1995

By Daniel F. Meyer, William C. Paschen

INTRODUCTION The problems involved with moving millions of tons of rock are being addressed by nationally recognized tunnel contractors who have converged in Chicago over the past 5 years. This wealth of expertise has been needed to meet the risk and challenge of constructing the world's largest network of underground tunnels which in turn has required a dramatic advance in the art and science of tunneling. These pioneers, through innovation, adaptation, and hard work, have eliminated the one major concern of The Metropolitan Sanitary District of Greater Chicago - how to move 8 million tons of rock. The Metropolitan Sanitary District of Greater Chicago (MSDGC) serves 122 municipalities covering 866 square miles in Cook County, Illinois. Of these cities, towns, and villages, 53 have combined sewer systems. On an average of once every four days, these systems overflow about 4 million gallons of combined sewage and rainwater into the area's rivers and canals. The overflows occur at approximately 640 outfall locations of which 10% are owned by the MSDGC, with the remainder of the points belonging to various other municipal bodies. All those who own these "point" sources of pollution are in violation of Illinois State and Federal regulations. To enable its member municipalities to come into compliance with State and Federal law, the MSDGC is implementing its Tunnel And Reservoir Plan (TARP). TARP is a regional solution to the problem of combined sewer overflow in the metropolitan Chicago area. TARP will greatly reduce the pollution of area waterways by intercepting the combined sewage and rainwater carried in the existing sys-

Jan 1, 1981

By L. G. Hagenbuch

Several factors need to come together in creating an integrate mining equipment dispatching system. At the hub of these factors ace the central dispatching formulas. This paper details the development of these central dispatching formulas and explores the combining of these formulas with other elements to create an integrated dispatching decision. WHY DISPATCHING? Truck dispatching implies and in reality should equate to mine equipment efficiency. Good truck dispatching will yield good mine equipment efficiency while poor truck dispatching will yield the alternative. Truck dispatching can either be automated through a computerized, process or it can be manual. Every mine with haul trucks has a truck dispatching system whether it is recognized or not. Even a system wherein the hauler operators determine where they are going for their next load is a truck dispatching system.

Jan 1, 1987

By O. Ogunsola, M. Downing

This paper gives a brief overview of impacts of coal blending on coal-fired power plants performance and discuses the preliminary results of an on-going study aimed at evaluating the effect of coal properties on the effectiveness, compatibility and thermal reactivity of coal blends. Plant survey studies reported no significant impacts on an existing plant designed for a high rank coal when switched to a blend of low- and high- rank coal. However, slight modification of some aspects (handling, fuel storage/stockpile, transportation, preparation, and general housekeeping) of plant design and operation may be necessary. The preliminary results of an on-going study at the Mineral Industry Research Laboratory shows that more compatible and better blends could be made from coals where ranks are closer than from those where ranks are far apart.

Feb 24, 1997

By Dai Wang

Stoppings are necessary ventilation control devices for effective air distribution underground. However, one of the major problems underground mining has is that every stopping is a potential leaking source. Since air always flows from a point of high pressure to one of lower pressure, and the total pressure at every point in intake airways is higher than that in the return airways, air will always tend to leak from intake to return (Tien, 1996). In many mines, less than half of the air entering the mine actually gets to the working areas; the rest of it simply short-circuits directly to return airways through leaky stoppings instead (Timko and Thimons, 1983). Leakage through a stopping occurs because of pressure drops across the stopping and available leaky path in stoppings. Empirical equation has been widely used to characterize the relation the amount of leakage and variables that affect leakage. However the use of this equation requires accurate information for constants which are not always readily available. It is the attempt of this paper to derive an equation similar to the Atkinson Equation that can readily be applied to characterize pressure-leakage relationship for any given stopping.

Jan 1, 1998

By M. I. Brittan

Cyanide leaching of two West African gold ores was studied in multiple laboratories to provide process-engineering data for plant design purposes. Unusually slow leach extraction kinetics were observed using routine cyanide leach test procedures with pregnant solution monitoring. Carbon-in-leach testing, however, showed normal rapid kinetic behavior, with the same ultimate gold extractions being reached in much shorter elapsed times. Kinetic curves based on washed solids assays also exhibited more typical leaching characteristics. The results bore all the hallmarks of some equilibrium inhibition of the leaching. It was surmised that ore gangue components were responsible for weakly adsorbing gold-cyanide complex reaction product, thereby holding up soluble gold in the solid phase. The term ?preg-borrowing? was coined to describe the reversible phenomenon and distinguish it from irreversible preg-robbing. The two ores investigated may represent an extreme form of a more general effect that in most instances might pass unnoticed. The effect can lead to misinterpretation of kinetic leach curve data and underestimation of calculated ore head grades.

Jan 1, 2008