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By Pierre Mousset-Jones, Felipe Calizaya

This paper summarizes the current research trends in the ventilation design for the construction of very long tunnels, and presents the results of leakage flow measurements in three auxiliary ventilation systems. The study includes an estimation of an important design parameter, namely, the leakage path resistance, and a discussion of its effects on the overall efficiency of a ventilation system. A sample problem is used to illustrate the calculations.

Jan 1, 1997

By J. E. Taylor

A detailed planning and design project has been undertaken at Callide Coalfields, as the first step towards implementing a fully integrated mine graphics system. The system, when fully installed, will support applications ranging from business graphics through to terrain modelling and computer-aided design. The conceptual design which will accomplish this is presented. The problems of retrospectively applying graphics standards to existing applications are discussed, and a practical solution outlined.

Jan 1, 1986

By A. B. Szwilski

The mineability and coal processing costs are influenced largely by the structural and physical properties of the coal seam. The mining process involves coal cutting, pillar support, crushing, and floating. A correlation between the rank, ash content, and coal strength/stiffness is discussed. The coefficient of variability of rebound tests on the face of various coal seams are compared with those of laboratory compressive strength tests by other investigators.

Jan 1, 1988

By G. R. Brunskill

The molybdenite flotation plant at the Magma Copper Co. San Manuel concentrator has been in operation since 1956. In January of 1980, the plant was converted from a hydrogen peroxide-ferrocyanide process to the current sodium cyanide-sodium hydro- sulfide process. This paper is an operational review of Magma Copper Co.'s molybdenite recovery circuit, column cell flotation experience, and use of on-stream X-ray fluorescence analysis.

Jan 1, 1987

By R. A. Womack, Alex Ruzycki

Over the past six years, 4.5 million tonnes (5.0 million short tons) of gold ore have been heap leached at the Alligator Ridge Mine. Ore is leached in successive lifts, resulting in heap heights of 20 m (66 ft). Recoveries from each lift are determined through an extensive post-leach drilling program. The relationships between heap height, recovery rate, ore preparation, heap construction, and leach solution application are discussed.

Jan 1, 1987

By J. S. Lewis

Beneficiation and physical and chemical processing of non-terrestrial materials will borrow strongly from terrestrial experience but will also involve the necessity of handling literally unEarthly feedstocks, reagents and environmental conditions. The present state of scientific and engineering understanding of the processing of non-terrestrial minerals, gases and hydrocarbons is reviewed, with the production of rocket propellants, life-support fluids, structural metals and refractories as the goal.

Jan 1, 1994

By S. Frimpong, N. Demirel

Overburden excavation is an integral component of the surface mine production chain. The walking dragline is the most economic production equipment for overburden excavation in strip mining. Draglines are capital intensive, and thus, investments in multiple units severely impact the economic viability of projects. The use of few dragline units results in highly concentrated production focus, which must be efficiently managed to derive the potential economic benefits. Efficient use of draglines requires a thorough knowledge of the powered functions, the 3D rotational and translational motions and machine-formation interactions within the operating environment. Dragline kinematics and dynamics are required to understand and characterize machine performance and efficiency. In order to sustain the high productivity in difficult operating conditions, the dynamics of the dragline must be modeled and analyzed based on comprehensive kinematics. This paper investigates the planar kinematics of the front-end assembly and its interactions with the formation during excavation using the “Vector Loop Analysis” formulation with comprehensive simulation modeling in MATLAB Simulink. The kinematic models are used to examine the translational, rotational and angular displacement, velocity and acceleration components of the dragline front-end assembly along defined bucket trajectories during excavation. The results are the precursors for comprehensive modeling to examine the load deformation, torque requirements and dragline stress loading profiles for improving machine health and longevity.

Jan 1, 2006

By Hasan Kolayli

Zeolites are common secondary components of a variety of igneous rocks. However it is extremely rare to reach such abundances to form a rock. An unusual rock composed almost entirely of natrolite, a zeolite mineral, has been discovered ; in a mountainous terrain called the Kop mountain range in the eastern Turkey. In the region, country rocks are essentially metamorphic rocks. These unique rocks are resulted through metasomatic changes acted on microdioritic and andesitic parent rocks occurring generally as dikes and stocks in the country rocks consisting chiefly of serpentinized harzburgites. These metasomatic rocks are investigated with respect to their mineralogical, petrographical, and geochemical characteristics. These products consisting dominantly of natrolite are termed "natrolitite" and those containing additional pargasite, an amphibol mineral, are termed "pargasite-bearing natrolitite or pargasitic natrolitite ". The dikes and stocks show concentric zoning, each of which has distinct chemical and mineralogical compositions: Na2O and H2O contents show enrichment outward from the core to chill zones whereas, SiO2 and CaO show depletion. Mineralogically, plagioclase variety, abundance and chemistry change outwards from the center due to partial to complete replacement of natrolite: anorthite contents of plagioclases decrease outward, which is indicated by A1203 and CaO decrease and SiO2 and Na2O increase, showing inverse relationship with increasing natrolite content.

Jan 1, 2005

By Charles D. Litton

This report describes a smoke particle detector which utilizes a novel three electrode configuration and 5.0 [] source of Americium 241. The detector operates on the principle of diffusional charging by a region of unipolar molecular ions. The detector is sensitive to particle concentrations in the range of 10 to 5 20 ug/m3. The detector is intended for use primarily as an early warning fire detector but has the potential for other applications of particulate monitoring. In particular, this report adresses the potential use of the detector for monitoring diesel particulate matter (DPM). To assess the viability of this application, particle size data obtained from in-mine sampling of both DPM and dust were used to derive detector sensitivity functions for DPM and dust as a function of their mass concentrations only. These sensitivity functions are dependent upon the average diameters and size distributions of the DPM and dust. Using the derived sensitivity function for DPM, experiments were conducted in a ventilated tunnel where the true DPM mass concentrations, measured using a Tapered Element Oscillating Microbalance (TEOM) were compared to the mass concentrations calculated using the detector sensitivity function. The agreement between the two measurements was good, indicating that with additional experiments, coupled with in-mine evaluation of the detector, refinement of the device for use as a continuous monitor for DPM appears feasible.

Jan 1, 1989

By Jacek Kolacz, Knut Lyng Sandvik

Fine grinding in an air swept and a grate discharge ball mill working in closed circuit with a forced vortex air classifier has been investigated in continuous laboratory scale. Minerals with different physical properties were ground down to 40, 20, and 10 micron top size. The shape of the product particle size distribution curve was investigated and specific surface (BET) was measured. During production of material with top size of 40 microns in an air swept mill, the capacity was up to 25% higher when compared to a grate discharge mill. This difference dropped to 180A during production of 10 micron top size material. A corresponding decrease in power consumption was observed. An important finding is that by regulation of the air flow rate through the mill, it is possible to achieve products with different specific surfaces and particle size distribution curve steepness. During production of the 10 pm material, the specific surface could be varied in the range 3 to 4.5 m2/g. Such powders could hardly be produced in a grate discharge mill because fine particles coated the grinding media and the lining. On the other hand the internal classification in the air swept mill kept the size distribution of the mill content relatively free of fines. This prevented a similar slowing-down of the air swept grinding process.

Jan 1, 1995

By D. W. Park

Longwall mining is considered to be the most efficient underground coal-mining technique in terms of coal extraction ratio, production rate and safety standards. Due to the increasing demand for higher coal production, the recent trends have been to use wider panels and to maintain a faster face movement. For these reasons, longwall mining can result in unexpected roof falls, excessive face convergence, shield damage and numerous maintenance problems, which can cause sudden interruption of coal production as well as serious safety hazards. Recent work at the University of Alabama has been dedicated to the development of a longwall strata-control and maintenance system that can integrate real-time shield monitoring, data presentation, analysis, forecasting and warning modules. This integrated system has been called LoSCoMS. The main objective of the system is to provide minute-by-minute stability and maintenance information such as the following: high-load, low-setting pressure, leg leakage, etc.; the analysis of various mining and geological parameters to determine past and present roof characteristics; and the forecasting of loading patterns for the following mining cycles, the next periodic weighting, etc. By using this unique system, mine operations personnel are well aware of past, present and future roof-loading patterns at the longwall face and, thus, proper safety measures can be taken ahead of time.

Jan 1, 1999

By Gary W. LaChapelle

Cyprus Miami Mining Corp. has a history of overcoming adversity through innovation and adaptation to changing conditions. Requirements to remain profitable in the 1990s include a combination of advanced technology, employee involvement and training, attention to customer satisfaction, environmental awareness and quality management. The Miami property is located in the Globe-Miami area of Arizona, 130 km (80 miles) east of Phoenix and 160 km (100 miles) north of Tucson. The complex is located in a high desert environ¬ment at an elevation of 1065 m (3500 ft). The region receives about 480 mm (19 in.) of precipitation annually. History Mineralization at the Miami property was first discovered in the 1880s, which led to underground mining of copper by the 1890s. In 1911, the Inspiration Consolidated Copper Co. was formed by combining the Inspiration and Live Oak Mines. Full-scale production began in 1915. Block caving methods were used at both mines. Open-pit mining commenced in 1948. Underground mining had ceased by 1954, and all production was obtained from surface operations. Innovation has been the key to Miami's success. Development of sulfide flotation and the ferric cure process for vat leaching were advanced at Miami. In situ leaching of oxide material, remaining after block caving had removed the sulfide ore, was also used.

Jan 1, 1993

By James H. Boettcher

Inflation and increasingly complex tax laws in the United States combined with rising national ism overseas have made the structuring of viable financing plans which meet the requirements of the various parties involved equally important in determining project success as the design of an efficient mining plan or selection of the optimal size equipment. Whereas the use of computerized analysis to design and evaluate the technical parameters of resource ventures is well accepted, computerized evaluation of the investment criteria (qualitative and quantitative) of the various parties to the project (mining firm, financial institution, product buyer, host government, etc.) is a more recent application which can make a material impact in strengthening project economics. By identifying the objectives of the parties and critically evaluating and testing them with the technical and economic/financial constraints on the project the sponsors can design a financial structure tailored to the attributes of the deposit. A myriad of new financial techniques have evolved for financing natural resource ventures, from "Commodity-backed bonds" to tax based limited partner- ships, but in every case the structure of the financing mechanism depends on carefully matching the parameters of the financial structure with the economic characteristics of the project and the objectives of its sponsors. This presentation outlines a methodlogy for computer based project evaluation in the design and structuring of stronger financial plans for natural resource ventures.

Jan 1, 1982

By Levent Ozdemir

The advantages offered by mechanical mining have been demonstrated in the underground mining of coal, evaporites and other soft minerals. Mechanical mining and the advancements in automation technoloogies have been the principal drivers towards the realization of enhanced productivity in soft rock mining. For past two decades, emphasis has been placed on developing mechanical mining technology for hard rock applications, to achieve similar productivity improvements and cost reductions. The benefits of mechanical mining are numerous, particularly in an industry where market conditions continue to dictate higher production and lower costs while maintaining high safety standards. Other benefits of mechanical mining include reduced ground support and labor requirements and the elimination of blast and diesel fumes. These benefits further make this technology an attractive alternative to drill and blast for hard rock mining. Mechanical mining is conducive to full implementation of remote control and automation technologies that are under development to achieve further productivity and safety improvements in underground mining. Mine development has been the main focus area for mechanical miners by manufacturers and mining companies. Potential applications include ore body access, haulage and ventilation drifts, undercut and exploration drifts. The economic use of this technology in mine production is still considered many years away. It would need a major technological breakthrough that would make mechanical rock fragmentation competitive with the large-scale, low-cost production blasting operations.

Jan 1, 1998

By Richard Meriwether Smith

Mining-related earthy bodies in contact with the atmosphere are now counted, generally, as minesoils. Because soils within this broad category are extremely young the influence of parent material is stronger than in older soils, where climate, organisms, and topography have had time to interact with near-surface rocks to form more distinctly differentiated profiles. Understanding of minesoil properties and processes is aided by definitions of rock types in terms of chemical, physical, and mineralogical characteristics that are, with some degree of consistency, translatable into soils. Geological correlations based on age or sedimentary sequences are helpful if they assure details of mineralogy and lithology, but our pedologic objectives demand that any conflicts involving rock types must be resolved in favor of distinctions having strongest implications for soil properties after mining. Chemically this approach emphasizes accounting of potential acid-base status, plant nutrient availability by adapted and calibrated extraction procedures, and absence of biotoxins. Physically it anticipates particle sizes, shapes, and arrangements in readily pervious soil profiles that will favor plant growth with desired levels of moisture and oxygen. Concurrently we are considering soil property suitability for uses other than growth of plants. Above all we need to be able to predict pedogenic processes in the particular environment, including rate as well as direction of chemical and physical change.

Jan 1, 1974

The design of solvent extraction plants has been generally based on the assumption of steady operating conditions in both the settler and the mixer units. However, recent experience in both large and small plants has shown this not to be the case. Mixer transients include start up aqueous locking and partial phase separation in secondary mixers, which both lead to reduced plant capacity or overflow of upstream mixers. Analysis of the hydraulic pressure profiles has generated new design methods to eliminate the effects of the partial or complete phase separation. Changes to the method of specification and selection of primary and secondary mixers have been made to eliminate the onset of partial separation during operation. The observation of settler operation has shown that it is also a dynamic process, even under "steady-state" conditions. Four transient phenomena have been identified that lead to internal circulating flows, poor disengagement of fine secondary haze and erratic and high entrainment levels in the discharges. A, first approximation analysis has shown that there are significant pressure differentials within settlers, and these change along the length and with the phase separation rates. A technique to control the effects of these transients was developed that allows plant performance to be improved beyond "standard" expectations. The design and selection of the settler internals is described. Key words: Solvent extraction, Mixer-settlers, Phase separation, Entrainment, Mixer transients

Jan 1, 2003

By Russell W. Hunt

The cave man of ages past took his wife-and family from the cave pointing to a fire he had built and beating on his breast said, "Look what I have done". Today man is taking his family back to a cave saying, "Come enter in because of what I have done". At the close of World War II Germany said if they had gone underground one year earlier with more of their operations, the war could have lasted four years longer with perhaps much of Britain devastated. The protection of the home front no longer rests with the soldier in actual combat. The battle will be won at home with the most careful kind of protection against missiles. After Nagasaki-Hiroshima Sir Winston Churchill said in substance "Up to now the Almighty has mercifully withheld from man the knowledge of these terrible weapons of destruction."

Jan 1, 1959

By M. A. Weaver

This paper will investigate the historic and present state of the bituminous coal industry within the Commonwealth of Pennsylvania, with special emphasis on surface mining operations. It will address pertinent parameters such as production, markets, quality, number and size of operations, price, and productivity from a statistical viewpoint. In addition, relevant statistical parameters of select areas of the Appalachian Coal Region will also be presented and discussed.

Jan 1, 1989

When looking for indicators for the mining business ? and these days who isn?t? ? one might need to look no further than the SME Annual Meeting. Held in Phoenix, AZ Feb. 28 to March 3, the meeting was, by almost any measure, a record-breaking success. Attendance included 4,937 industry professionals. Many of whom, feeling rejuvenated following the worst economic recession since the great depression, were greeted with a record 630 exhibits and 103 technical sessions covering all aspects of the mining and minerals business. Adding to the general optimism of the future was a celebration of the past and re-cent achievements in safety and health. The theme of this year?s meeting was ?Celebrating 100 Years of Mining Research? and the emphasis on advancements in safety was evident from the keynote address that kicked off the conference, to the field trips, to the Resolution and Safford mines that concluded the meeting.

May 1, 2010

By Robert F. Reeves, Stephens A. Avary

Introduction People, systems, methods, and organization make up maintenance productivity. Methods promote efficiency in operations, systems ensure consistency and continuity, and organization maintains direction and control. The common denominator in these techniques, though, is people. Management systems can be technically correct, but fail to work because management systems do not work by themselves - people make them work. Therefore, the foundation for mine maintenance productivity must begin with the people involved. Traditionally, the emphasis placed on mine maintenance, as opposed to production, is not proportional to the impact that maintenance has on a mining operation. The performance and productivity of mine maintenance substantially affects the operating costs, revenues, and profits of the mine. The mining industry has recently experienced a period of economic depression. While it has created financial problems in all segments of the industry, it has caused the industry to focus on the need for improved productivity. Mining companies that have made investments in productivity during this period will have a competitive edge during the recovery, and mine maintenance may be the best place to put that investment. Future lost production and maintenance cost problems can be avoided if mine management has the foresight to seize the opportunities that now exist. Background Technological improvements over the last 30 years have been dramatic in the industry. Before these changes, mining equipment was not very sophisticated. So maintenance needs were not very sophisticated. Maintenance people were not required to have any formal training in mechanical or electrical skills. At many mines there was no formal maintenance organization. The mechanic was a part of the section crew and received direction from the face boss. Mine maintenance was not a function, it was a task. Technological change in mining came about in response to an expanding economy and greater demand for mined products. The past 20 years brought about a change in the kind of individual needed to mine ore and coal, and an even greater change in the person needed to maintain equipment. Equipment went from mechanical and pneumatic to complicated electrical and hydraulic. Maintenance progressed from being a task to being a function. Types of Mechanics Mine maintenance workers can be grouped into three categories based on experience: mechanics with more than 20 years, five- to 10-years, and less then five years. These groupings have influenced mine maintenance productivity. The 20-plus mechanic has been the foundation of the maintenance force. He had no formal training and his skills were acquired on the job. As new equipment was introduced, he learned to repair it by trial and error. Not all of what he learned was correct. Personal initiative and conscientiousness are characteristics of this group. They have experienced the bad times and the good, and appreciate the opportunity to work. The five- to 10-year group worked with the older, more experienced mechanics to acquire maintenance skills. These mechanics came in during industry boom times, and many progressed quickly by being in the right place at the right time. Many in this group have difficulty with diagnostic trouble-shooting, and depend on changing out parts to identify problems. This group is generally more mobile and less apt to have a strong work ethic. Mechanics with about five years experience have vocational training, some formal education or basic skills training. Like the five- to 10-year group, these miners are mobile and tend to move readily to satisfy their changing needs. These two younger groups are less apt to feel any loyalty to the employer or obligation to be productive. Their attitudes and abilities reflect the influence of their general age groups, and has a definite impact on mining productivity. Past Requirements In the 1960s, the basic requirements for a maintenance supervisor was that he be a top mechanic, get along well with the men, and be a hustler and improviser. He learned the details of new equipment as repairs were needed. Oftentimes, this individual would be the only person on the property with the ability to read prints, use diagnostic testing equipment, and troubleshoot using an analytical approach. This approach to maintenance is sufficient when the equipment design is reasonably uncomplicated. Management Changes As technology progressed, organized labor gained strength, government regulation increased, and the job of supervising and managing people had to change. The environment has changed and

Jan 11, 1983