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By C. C. Bailie

This paper will be concerned with those mineable coal measures at depths necessitating deep mine operations in the range of 200 feet to 800 feet in depth. The area is generally classified as the Southern Illinois Field but more specifically includes that part of the state south of a line extending from St. Louis, Missouri on the west to Vincennes, Indiana, on the east. This embraces an area which presently includes a total of 38 shipping mines and 5 local or truck mines. Of these shipping mines, 22 are deep (shaft or slope) mines and the remaining 16 are strips. The average annual production of the shipping mines is around 29 million tons. The presently classified mineable reserves of the area are estimated at around 70 billion tons.

Jan 1, 1964

By Odin Wilhelmy

Agriculture in the United States today is becoming more and more a business, rather than a way of life. In the light of this, it behooves the farm-supply industries that provide the American farmer with his tools of production--feed, fertilizer, machinery, and the like--to give even greater attention than they have in the past to meeting the needs of the farmer-businessmen they are serving. Increasing competition among the companies that make up these industries merely accentuates this need for better service. An opportunity for such improved service, not yet fully realized, exists in the fertilizer industry today. That opportunity lies in the increased transportation of fertilizer ingredients by water. However, before the benefits inherent in this increased water movement of fertilizers can be fully realized, certain obstacles must be met and overcome. It is the purpose of this paper to outline the nature and magnitude of this opportunity, to point out some of the roadblocks and the steps that can be, or are being, taken to remove them, and to indicate some of the rewards that would logically stem from success in these efforts.

Jan 1, 1961

By A. Mertzanis

The way and methods used for the surface mining of bauxite until the end of the twentieth century in the area of Ghiona, resulted in a significant burden to the natural environment, especially in the cases where it covered extended parts of forests and forest areas as well as important geomorphological formations. The impacts from the surface mining of bauxite which in fact constitute the object of this study relate mainly to the interruption of the natural continuity of the land relief and the alteration of the natural geomorphological activities and are due to: a) the alternating excavations with fronts of great heights, b) the depositions of large volumes of waste materials which originate from the revealing of the ore and c) the dense road network constructed in order to get access to the mine locations.

Jan 1, 2006

By Pedone Ezio Michele, Mohamed Dahir Holad

"The 4c segment is a part of the ""Oman National Railway Project” linking the mining area in the surroundings of Thumrait and the port of Salalah. It is 90 km long and the last 40 km stretch crosses a mountainous area near the city of Salalah. The project includes the excavation of a 33 km double and single bore tunnel and 10 km of safety tunnels. This mountainous area is a holiday destination for Omanis, thanks to its beautiful landscapes, especially in summer time due to the monsoon rains. The tunnelling design had to take into account both these environmental constraints and the limestone rock formations crossed, which are affected by significant karst features. Given the context, the conventional tunnelling method has been preferred. INTRODUCTION The Oman Railway Project (Fig. 1) covers the construction of approximately 2,150 km of railway line for freight and passenger transport which will connect together Oman’s main towns and industrial sites and it will form part of the Arabian Peninsula railway system “GCC Project”. The non-electrified double-track railway line must guarantee a speed of 220 km/h for passenger trains and 120 km/h for freight trains and must guarantee the transit of AAR (Association of American Railroad) H and D plates using clearance envelope according to AREMA (American Railway Engineering and Maintenance-of-Way Association) requirements. The design alignment must have maximum radiuses of curvature of 3,250m and a maximum gradient of 1.0%. The project is divided into 9 constructional and functional segments. •,Segment 4c will be constructed in the southern region of Oman, close to the border with Yemen, to connect the town of Thumrait with the Port of Salalah. •,Segment 4c will run through the Dhofar region and will be mainly used by the freight traffic which currently travels by road."

Jan 1, 2016

By Michael Schmalzel

Freeport-McMoRan Copper & Gold, Inc. (FMI) will soon begin copper production from the Dos Pobres and San Juan deposits near Safford, Arizona. Ore reserves total 615 M tons grading 0.36% copper, predominantly as chrysocolla. Copper extraction will be by leaching with sulfuric acid. Fluor Canada Ltd. provided EPCM services to design an ore handling and conventional SWEW facility capable of producing a nominal 240 million pounds per year of cathode copper. The ore handling facility will process 114,000 tons per day of ore through three-stage, open-circuit crushing followed by agglomeration and product placement on the permanent leach pad. Stacking of ore on the leach pad will utilize Terra Nova Technologies' "Super Portable" mobile stacking system. The stacking system fleet consists of 13 self- propelled, crawler-mounted mobile conveyor units, each with 72-inch-wide belting and a capacity of 6,800 tons per hour, including ten 250-foot-long portable conveyors, a horizontal feed conveyor, a 285-foot-long horizontal conveyor and a 220-foot-long radial stacker. PROJECT BACKGROUND Project History The Safford Leach Project is located in the Safford mining district in Graham County, Arizona, approximately eight miles northeast of the town of Safford and 170 miles east of Phoenix. The 3,360-acre property is located in the Gila River Valley, immediately south of the Gila Mountains, at elevations between approximately 3,000 and 5,400 feet above sea level. The Safford Leach Project is comprised of the Dos Pobres and San Juan deposits, two of five known copper ore deposits in the Safford mining district.

Jan 1, 2008

By Janet Briggs, Michael Vertes, J. F. Shirley, R. E. Cutherbertson, Alexander Sutulov, J. D. Vincent

Molybdenum, the 42nd element in the periodic table, is now a very important metal in industry of the United States and the world. Chemically, it is a very complex element having valences of 0, +2, +3, +4, +5, and +6, and can exist as a mixture of these valences in many compounds. It was discovered and separated by Scheele in 1778. At the present time, molybdenite is the only important commercial source of molybdenum. Molybdenum occurs in some 12-14 different recognized minerals, but practically all of the production is molybde¬nite. As late as 1915, it was considered a rare metal. Germany made extensive use of it during the first world war, which resulted in the establishment of a molybdenum industry in the United States at Cli¬max, Colo., in 1917. It was not until the mid-1920s when its introduc¬tion to steelmaking developed for the US automobile industry that the metal gained important acceptance. The first notable example was the Willis-Saint Claire automobile introduced in 1921 by C. Harold Willis, formerly chief metallurgist for Ford Motor Co. Molybdenum has also been produced in the US from wulfenite (PbMoO4) from Arizona and Nevada, and a small amount of molyb¬denite was produced up to the early 1970s as a coproduct from two molybdenum-bismuth mines in Quebec, Canada. The first byproduct production of molybdenite from a copper con¬centrating operation was achieved at Cananea, Sonora, Mexico, and was followed shortly by the Utah division of Kennecott Copper Co. in the mid-1930s. This section of the Handbook is divided into four main subdivi¬sions: Chapter 2, which deals with the concentration and recovery of molybdenite from primary molybdenum ores; Chapter 3, which deals with the recovery and separation of molybdenite as a byproduct from copper production; Chapter 4, which deals with the conversion practices employed for converting molybdenite to the oxide or metal form; and Chapter 5, which covers the uses of molybdenum in steel¬making, chemicals, pigments, lubrication, catalysts, etc. The Free World molybdenum production, for the past eight years from all sources, is shown in Table 1. 2. Primary Molybdenite Ores General In 1978 there were four primary molybdenite recovery plants in operation: Climax, Endako, Quests, and Henderson. For over half a century the Climax mine has been by far the largest and most important source of molybdenum in the world. During the early 1970s a few primary molybdenite mines in British Columbia were shut down due to adverse economical conditions. The largest of these was British Columbia Molybdenum, formerly owned by Kennecott Copper Corp. The Climax plant and operations are described in detail and the opera¬tions of the other plants are summarized following a general discussion of recovering molybdenite from primarily molybdenite ores. Recovery of molybdenite as a byproduct will be taken up in Chapter 3. Geology Molybdenite production from mines in which it is the sole or preponderantly important mineral is confined to ore bodies in granites or igneous-type rocks or pegmatite dikes. More than one state of mineralization is sometimes present as at Climax, York, Hardy, and Questa. In the case of Climax, important byproduct recovery of tung¬sten, tin, pyrite, and monazite is also attained. The molybdenite is commonly disseminated very finely in the siliceous granitic gangue but does occur in stringers and blebs in silicified mineral solution channels. Treatment of Primary Molybdenum Ores All primary molybdenum ores are low in molybdenite, the content ranging from less than 0.20% MoS2 to a high of about 0.40% MoS2. A high resistance to grinding is a common ore characteristic combined with a habit of very fine dissemination of molybdenite in the siliceous portion of the ore. Because of low MoS2 content, high hardness, and fine dissemination of molybdenite in primary ores, it has been necessary to develop a special mill treatment which yields an accepta¬ble recovery at a reasonably low milling cost. Essentially, the treatment consists of intensive rougher flotation at a relatively coarse grind with production of a low grade rougher froth containing a substantial percentage of the molybdenite in the form of low grade middling particles, followed with multistage regrinding to liberate the locked molybdenite and several stages of flotation cleaning to produce a finished grade concentrate. Rougher flotation on pulp ground to ap¬proximately 35 mesh is common practice, even if complete liberation of molybdenite from siliceous gangue may require regrinding to 200 mesh. The flotation of middling particles with a very low content of molybdenite in the rougher flotation step has been made possible by the application of a combination of reagents first developed at the Climax mill and used with some modification in the treatment of all primary molybdenum ores. The reagents commonly employed and their functions in flotation are:

Jan 1, 1985

By Yi Luo

Subsidence events occurred over inactive room and pillar (R&P) mines, including abandoned mines or sealed portions of active mines, are classified as unplanned subsidence because of their timing and distribution are unpredictable. When investigating such subsidence cases, many uncertainties exist and disputes often focused on whether the observed structural damages are caused by mine subsidence or other natural or artificial causes. However, solid evidences to identify the causes are often lacking. In order to conduct a thorough and impartial investigation, good knowledge in subsidence theories a

Jan 1, 2009

By Richard C. Fox

"Why geophysics? We will have to drill anyway." Reliance on geophysical methods for detailed target appraisals will increase as direct surface evidence becomes more subtle. This will create a need for more effective and efficient geo- physical programs. Numerous computer-based techniques that deal with a broad range of geophysical problems are described in the literature. The purpose of this chapter is to provide a framework for the systematic application of these techniques to effect an overall optimization of the geophysical appraisal. The concepts described are not technique specific, but should serve as a guide for increasing the effectiveness and efficiency of any geophysical program. Fig. 1 shows a generalized flow chart of the major aspects of the program described. The three main subdivisions of a 'geophysical program are discussed: (1) survey design, (2) data processing, and (3) data interpretation. Detailed flow charts, outlining the goals, the requirements for meeting the goals, and the steps followed within each subdivision are presented at the beginning of each section. The objectives and type problems of each subdivision are defined, followed by a description of applicable computer methods. . References are cited that give a general cross section of computer techniques available in the literature, and examples are given in each subdivision to demonstrate basic concepts and the use. of computers in solving the type problems.

Jan 1, 1979

By James R. Jones

The concern for air pollution goes back centuries as will be seen from this quotation : "Strife and coal, it seems, have a hand-in-hand historical relationship. It was thought by some . . . in the Middle Ages that burning coal filled the air with dangerous poisons. So great was the concern that in 1306 King Edward I of England passed the first and unquestionably the harshest air pollution legislation edict that history will record. His proclamation declared the use of coal an act punishable by death." As related to coal mining, the air pollution problem is primarily that of its customer when using the fuel. Thus the major impact relates to markets for coal rather than the actual mining operation itself. In the vicinity of the coal mine the problem is principally related to fugitive dust from roads, transfer facilities, loading facilities, crushers, etc., and particulate matter (dust or fly ash) from thermal dryers and air cleaning tables.

Jan 1, 1981

By Andrzej Walentek

This paper presents the results of numerical modeling of the fractured zone around longwall gateroads. The numerical computations have been based on the results of underground measurements of the fractured zone around longwall gateroads, which were performed for various geological and mining conditions and measured with the use of the endoscopic method with a digital camera. Having results of the underground investigations, trials of duplicating them by the Finite Element Method using software PHASE and the Hoek-Brown failure criterion were performed. In order that the fractured zone predicted by the model-based computations closely simulate that measured underground, some selected parameters in the Hoek-Brown failure criterion were modified based on the earlier determined relations used for prediction of the roof-to-floor convergence in longwall gateroads. As a result, the model-based computations produce results very close to those obtained from the underground measurements. Determination of the fractured-rock zone around the mine roads is of great importance to mining practice, especially in planning and designing supports for longwall gateroads. The influence of the front abutment pressure causes the fractured rock zone around the roads to increase and results in an increase of support load. Moreover, proper determination of the fractured rock zone is one of basic elements in the process of planning roof bolting for mine workings.

Jan 1, 2009

By T. Carl Jr. Shelton

Surveying and mapping are used to locate and visually portray objects, lines, or areas in relation to a reference point or line. The actual making of the measurements to locate the objects and points falls under surveying while mapping is concerned with putting the survey information into a graphical form. Generally, the type or class of proposed survey depends on the precision required. Some surveys may need only approximate measurements which can be obtained by simply pacing or by using an ordinary measuring tape; others may require much accuracy, thus calling for the use of an engineer's transit or theodolite along with a graduated steel tape for horizontal measurements, or a level and a graduated rod for measuring vertical distances. Mapping is likewise dependent on accuracy requirements. For example, a general layout showing the relative position of surface facilities may not call for a large scale of dimension or great precision whereas for detailed work, a large scale plus care in plotting points and drawing lines and curves are important factors.

Jan 1, 1981

By Paul C. Schmall, John F. Donohoe, Arthur B. Corwin

In the aftermath of the September 11th attack on the World Trade Center, groundwater control was of immediate concern. Water in?ow from the adjacent Hudson River through the compromised slurry wall ‘bathtub’ surrounding the site, ruptured water and sewer mains, and saturation from fire hoses all contributed to an already critical situation, further hampering the recovery and rehabilitation effort. An extensive pumping and deep well installation program was initiated, focused on reducing the hydrostatic loading to the severely damaged perimeter slurry wall.

Jan 1, 2003

By James J. Fallon

Last summer Larry Miller of Roberts & Schaefer told me that his AIME committee would like me to present some thoughts on the marketing of industrial mineral fillers and pigments to this illustrious group in Las Vegas. Shortly after, Brian Coupe of "Industrial Minerals" (the magazine) notified me that I would be presenting a paper to the Fourth International Industrial Minerals Congress in Atlanta this June. It seems to me now it might have been more appropriate to reverse the papers. Las Vegas, a town based on risk, might want to hear what we have to say in Atlanta. The subject for June is "Risk Philosophies of U. S. Industrial Minerals Companies". However, upon reflection, marketing of industrial minerals reflects risk philosophies to a considerable extent, so we'll cut the deck and deal on the subject of marketing.

Jan 1, 1980

By P. M. Soupios

The study of soft soil (wastes above the rock bed) an issue of great importance in civil engineering, is usually addressed by drilling boreholes. This method is rather expensive and time-consuming and although the information obtained is usually accurate, on the other hand it is much localized. Recently published researches have demonstrated the ability of the combination of geophysical exploration methods to estimate the thickness of deposited wastes, which provides the layered structure of the study area and certain, method depended, mechanical parameters as well. By theory, the frequency of resonance of an upper layer is a function of its thickness and the average shear velocity in it. Furthermore, the application of H/V spectral ratios of micro-tremors is a fast, straight forward and cost effective methodology, yielding the determination of the main resonant frequency of the soil. Based on this framework, 20 microtremor measurements have been carried out in a Landfill in Heraklion-Crete. Some of these measurements were deliberately close to drilled sites, where the basement had been reached. Three electrical resistivity tomographies were also used, in order to define the landfill structure such as, thickness, determination of different wastes distribution in the study area and other parameters. In addition, estimation of predictive Vs using empirical relationship between shear velocity and penetration resistance (SPT?s) were also conducted. Knowing the thickness and the resonant frequency, we estimated the shear (Vs) velocity of the waste cover. The final Vs model was confirmed using the results from the Vs-SPT correlation. The combinative implementation of the above mentioned geophysical and geotechnical methods have successfully defined geometrical and geotechnical/geophysical characteristics of the area under investigation in a fast and cost effective way.

Jan 1, 2005

By F. L. Wilke

Underground mining is a very complicated and complex industrial activity. The uncertain and, in most cases, the incomplete knowledge of the geological and mineralogical nature of the deposits can cause unforeseen difficulties. For a safe and uninterrupted operation, in addition to good planning and scheduling, reliable and up-to-date monitoring and control of all processes and conditions become necessary. Today, this is even more important in view of increasingly difficult working conditions, poorer grades, and more complex and expensive machinery. In short, large capital investment and higher risk of financial losses are involved in modern-day mining operations. Monitoring and control of the underground mining process has become a very complex and difficult task in itself. Many different systems are available, and the correct choice .is of utmost importance from both the economic and safety points of view. This chapter will deal with aspects of underground production monitoring and control. There are, however, many other areas of equal importance which are covered in an excellent manner in a hand- book by Olaf (1976) on monitoring and control of underground operations.

Jan 1, 1979

By A. B. Holland-Batt

Following a relatively static period in the 1960s and 1970s when incremental development rather than innovation was the norm for gravity separation, the last 15 years has seen a number of new developments in this area. The paper briefly reviews the traditional gravity separation techniques and then examines the newer developments such as centrifugal separators. Particular emphasis has been placed on novel devices or improvements that offer either better control or improved performance.

Jan 1, 1998

By John T. Langstaff

Rock bursts in the deep metal mines of the Coeur d’Alene district present an ever increasing problem in the safe and economic mining of the district’s silver, lead and zinc ores. Hecla Mining Company operates two mines in the district - the Star, a 1100-ton/day lead-zinc mine, and the Lucky Friday, a 750-ton/day silver- lead mine. Rock burst problems at both operations prompted Hecla management to make an all-out attempt to find a practical method of predicting and eventually controlling these bursts. Research by personnel from the Denver Research Center of the Bureau of Mines at ASARCO's Galena Mine indicated that a recognizable pattern of seismic activity preceded some bursts and this activity could be precisely monitored by present- day, off-the-shelf electronic devices. Using information gained by the Bureau and other sources, Hecla designed and installed a 24,- channel seismic monitoring system in the Lucky Friday mine. Installation was completed in December 1973 and after a year of successful operation, it was decided that a similar system would be installed in the Star mine. This second installation was completed in June 1975. Both systems are now operating and providing continuous information on underground seismic activity. Each monitoring system consists of a network of geophones with attendant amplifiers that are connected by shielded cable through an interfacing device to a computer. The origin of each seismic event is determined by the computer and a three-dimensional location is printed out. This information is plotted daily and is used to pinpoint rock burst prone areas and chart their relative seismic activity. This paper will review the causes and effects of rock bursts in the Coeur d'Alene district, the equipment and operation of the microseismic system at the Star and Lucky Friday mines, and the results obtained to date.

Jan 1, 1977

By B. J. Arnold

Froth removal rate is perhaps the most important parameter in scaling up from laboratory tests to plant froth flotation circuits. The WEMCO froth factor, the percentage of the froth height over the lip of the cell, accounts for the difference between laboratory and plant froth removal rates. As laboratory tests are generally run with a high pulp level, laboratory results are directly comparable to plant results only when a high froth factor (high pulp level) is run in the plant. When a plant does not have a high pulp level, laboratory results must be modified by using a ratio between laboratory and plant kinetics to predict plant results. This ratio, which accounts for the froth factor is important in testing any new reagents or reagent dosage levels. CQ Inc. researchers have used predictive scale-up equations using this froth factor coupled with equations for kinetics and the residence time distribution in the froth flotation cells. These equations show that modifying the froth factor in the plant can have a large impact on flotation cell yield and reagent use. EQUATIONS DESCRIBING FROTH FLOTATION Scaling up from laboratory- to plant-scale coal froth flotation has been the subject of much research and debate over the years. Determining the proper rate equation to describe flotation kinetics and an equation to describe the residence time distribution in a bank of flotation cells have been particular areas of study. As shown in Tables 1 and 2, various rate equations and residence time distribution equations have been proposed in the literature. These equations consist of one or two parameters giving the rate constant(s) in units of time-1 and a parameter for recovery at infinite time, [Roo]. Dowling, Klimpel, and Aplan (1985) evaluated the rate equations in Table 1 for their ability to fit froth flotation kinetic data and found that all of the equations give reasonably low standard errors. Several of these equations, however, proved to have superior confidence limits for the parameters. Other equations have also been proposed to describe the recovery versus time profile. Most recently, Diao et al. (1992) proposed a first-order form with a sine wave distribution. As indicated in Table 2, investigators have suggested many equations to describe the residence time distribution in continuous froth flotation. To measure the water residence time distribution in a bank of cells, a soluble tracer is often used, with the level of tracer being measured over time at the tailings discharge. This response is then put on a dimensionless basis as described by Austin et al. (1984) in order to compare mixing behavior between cells or under different conditions. Coal flotation cells are generally of the flow-through or hog-trough variety allowing for some degree of backmixing and short-circuiting. While the water residence time distribution (see Figure 1) at the end of one cell in a bank of 1.4 cu ft WEMCO froth flotation cells may approximate perfect mixing conditions (Arnold, 1989), the water residence time distribution at the end of a bank of cells does not. Figure 2 shows the RTD for various flotation cell types compared to that for perfect mixers in series. To better describe the water residence time distribution in coal froth flotation cells, Van Orden (1986) used an equation similar to the perfect-mixers-in-aeries equation. This

Jan 1, 1993

By Lawrence K. Nordell, Vinit Sethi

Published standards and specifications do not adequately cover engineered class pulleys for modern high strength steel cord belt conveyors. This paper discusses the Conveyor Dynamics, Inc. (CDI) design criteria and stress analysis techniques emphasizing the finite element method (FEM), fatigue failure criteria, design limits and manufacturing requirements to ensure successful and safe pulley installations.

Jan 1, 1993

By Jorma Miettunen, Reijo Kalapudas, Pertti Koivistoinen

A new method for measuring the mill filling was developed by Outokumpu’s Pyhäsalmi concentrator during 1989-90. The method utilizes the power draw oscillation which is caused by the mill lifters. Each lifter bar causes a peak in the power draw and thus a continuous oscillation results. In a fixed time scale, the oscillation peaks will shift as the lifter bare hit the mill charge sooner or later depending on the volumetric filling of the mill. Thus the measuring method is based on the phase shift of the power oscillation. So far the measurement is utilized for maximizing throughput of the primary mills at Pyhäsalmi and Enonkoski concentrators and at Harjavalta slag concentrator. The paper describes the new method and the results achieved.

Jan 1, 1992