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By R. Hardy

LaModel is a boundary-element program capable of calculating the displacements and stresses in thin bedded deposits such as coal, salt, or potash. Throughout its history, it has continually been upgraded in order to expand analysis detail and stay current with the latest advances in computer technology. The most recent enhancements include: an increased grid size capability, a significant increase in the speed of the automatic grid generation using an AutoCAD visual interface, implementation of subsidence-based horizontal strain calculations for multiple-seam situations, and pillar safety factor calculations. To demonstrate these new features, a multiple-seam case study of a longwall panel undermining an active set of main entries is presented.

Jan 1, 2006

By Earle Faig

Along with other transportation modes, the barge industry will be greatly effected by trends in domestic coal production. Traditionally, coal has been one of the major commodities moved by barge. Now, because of events in the international energy market, coal is finally getting the recognition it deserves as a major component of the country's energy program. Perhaps even more significantly, a series of events have caused other countries to turn to the United States as a source of coal. Although the outlook for coal demand is optimistic, it will be greatly influenced by the ability of the transportation sector to handle the additional traffic. Because of our long experience in moving large quantifies of coal, the barging industry is in an excellent position to capitalize on coal's increased popularity. A brief description of the barging industry should facilitate the discussion of coal as it relates to the barging industry. Barge companies operate on a 40.23-Mm (25 000 mile) river system which includes the East and West Coasts and the Mississippi River System. Included in the Mississippi River System are the Allegheny, Monongahela, Kanawha, Ohio, Illinois, Missouri, Tennessee, Cumberland, Arkansas, Warrior - Tombigbee and Mobile Rivers as well as some smaller tributaries. The Gulf Intracoastal Waterway, which stretches along the Gulf Coast from Brownsville, Texas to Apalachicola, Florida, is also considered part of the inland waterway system.

Jan 1, 1981

By Walter J. Pachucki

Mining equipment maintenance costs account for a major portion of a mine’s total operating expense. A reduction of maintenance costs while providing required equipment availability translates directly into increased profit for a mine. Therefore, having in place a successful maintenance program can be management’s most direct route to increased profits. One key element of a successful maintenance program is a practical and effective recordkeeping and information system. In recent years, many mining operations have invested in the development or purchase of computerized maintenance information systems. Computerized maintenance information systems can serve as a valuable tool in managing mining-equipment maintenance. They can also be a costly, frustrating waste of time. Why are some systems successful at one operation but a failure at others? Should all mines use computerized maintenance information systems? How does management decide what maintenance software is best for their operation? In an effort to to answer these questions and to better understand what is required to make a mining maintenance information system successful, a study was recently conducted on maintenance information systems used in the mining industry.

Jan 1, 1991

By D. M. Loring

Radon progeny have been a health and safety concern for miners since the mining of radioactive minerals began. Through the ?nuclear age?, it has become better understood and the regulations have become more robust. Ventilation and control practices have improved, thus reducing miners? exposures. This paper provides an overview of radon in mining, the progress of the regulations, and discusses some of the uranium miner studies that contributed to the knowledge of the pathology of radon.

Jan 1, 2009

By C. H. Bucknam

Classical acid-base accounting using modified Sobek titration methods has resulted in interpretation of results for materials with neutralization potential (NP) less than 20 tons of CaCO3/1000 tons of material (2% CaCO3) as "uncertain" due to lack of sensitivity within that content range. Standardization of a "fizzless" acid neutralization potential (ANP) method was undertaken in the American Society for Testing and Materials (ASTM) International using two ranges of sulfuric acid additions based on reaction pH and carbonate carbon estimates rather than subjective fizz testing as well as hydrogen peroxide additions to correct for mineral acidity. The method is identified as the acid neutralization potential acidity (ANPA) titration method. During interlaboratory testing a positive bias was discovered within the "uncertain" range which was further investigated and resolved by increasing the test sample weight from one to five grams for samples needing improved accuracy in materials with ANP <2% CaCO3. Test results from the interlaboratory testing of the low range method is presented and compared with the results from the original ANPA method in the paper.

Feb 27, 2013

By Lloyd M. English

Accurate knowledge of the gas content of coal seams has always been important, according to the work of W. P. Diamond and J. R. Levine, 1981, but is becoming increasingly important for several reasons: Excessive gas emissions in the mine can create explosion hazards. Depletion of shallower coal reserves is forcing underground operations to greater depths where coal gas content is often greater. Natural gas prices and the need for new energy sources make naturally occurring coal gas a potential resource of economic interest. Information on coal gas content will impact mine designs, mine ventilation system specifications, and the effectiveness of methane control procedures used. Accurate resource assessment is needed for projecting and designing potential gas utilization enterprises. The emphasis upon methane hazards in mining operations, and upon potential methane utilization, has led us to improve upon the procedures used to determine coalbed methane levels.

Jan 1, 1984

By R. J. Weigel

The Santa Fe Railway serves the dominant U. S. potash producing region which is centered at Carlsbad, NM. This rail system extends over 12,000 miles stretching from Chicago to the Texas Gulf Coast to the state of California. (see Figure 1) Since Carlsbad mining operations began in the 1930?s, Santa Fe has been transporting potash to many of the important grain producing areas of the country and to the major ports in Texas and California. Santa Fe has maintained a close relationship with the potash companies and has adopted a marketing philosophy of attempting to maximize opportunities for the Carlsbad producers where it is mutually beneficial. Potash has been an important commodity for the Santa Fe. It accounted for 8% of our revenue in 1965 and 3% in 1984. In the 1950?s, Carlsbad became the second largest revenue producing point on the Santa Fe. But this prominent position has diminished as ore reserves became depleted, imports flooded the U. S. market, and truck transportation developed.

Jan 1, 1985

By V. A. L. Breguncci, A. H. Martins, C. P. Ribeiro Jr.

This work presents experimental results for the recovery of gold present in alkaline cyanide solutions by using the electroelution technique of strong-base anionic polymeric resins IRA 402-CL from Rhom and Haas-Brazil Ltd. loaded with gold. This technique of electroelution of anionic polymeric resins is based on the removal of metal ions adsorbed to the resin, resulting from a potential difference applied between the cathode and anode in an electrolytic cell. The electrolytic cell was composed of an aqueous solution with suitable chemical characteristics and an anionic polymeric resin bed loaded with gold. The resin used in the experiments was loaded using synthetic alkaline gold cyanide solution with 1.0 g/L of gold. The variables studied were electroelution time, cathode current density, distance between cathode and anode and the electrolyte chemical composition. Statistical methods made it possible to establish the optimum conditions that would achieve satisfactory gold recoveries by the electroelution technique. The statistically predicted response for the resin loaded with gold by percolation was 16.5% gold recovery, 2.0 A/m2 cathode current density, 20-mm distance between electrodes and 6.0 hrs electroelution time. For the centrifuging system, the statistically predicted response was 7.41% gold recovery under the following conditions: 0.25 A/m2 cathode current density, 1-mm distance between electrodes, 3.5 hrs electroelution time and 10.9% NaOH in the electrolyte chemical composition.

Jan 1, 2002

By D. Diggins

Experimental apparatus for the determination of powder wettability is described. The principle of the technique is based on the measurement of the equilibrium capillary pressure in a packed bed of particles. Both the macroscopic solid-solution-vapour contact angle, e, and the specific surface area, A(m2g-1), of the powder, can be obtained. Experiments on angular quartz particles have been performed. A wide range of situations have been covered: hydrophobic and hydrophobic particles wetted with water, a variety of organic liquids and solutions of surfactants. The results show that reliable and reproducible values for 0 and A for angular and relatively coarse powders can be obtained with the proposed equipment for advancing liquid fronts in the absence of soluble surfactants. In the latter case and for receding liquid fronts in general, only qualitative trends have been obtained.

Jan 1, 1992

By A. Martikainen

Field tests concerning a fog mesh method for fog removal are discussed. The first tests were performed at the Pyhäsalmi Mine, Finland. As this study gave promising results, further studies were completed at the Orivesi Mine. The results of these most recent field tests are presented and the two studies are compared. The Orivesi test set consisted of four materials. These included air filter fabric, fibrous filter fabric, a plastic greenhouse mesh, and an aluminium mosquito net. The variation of the Orivesi results was more noticeable than what was found previously. The best fog removal effect of all tests was achieved with the aluminium mosquito net, while the plastic green-house mesh performed worst. The humidity reduction by aluminium net was more profound than any of its precedents. More mesh materials will be tested in the near future.

Jan 1, 2007

By Ron M. Canon, John M. Begovich

Chromatography, ion exchange, and other techniques based on the interaction of solutes with solid phases offer versatility, high resolution capabilities, and near-universal potential applicability for the separation of valuable constituents in liquid solutions. The expense associated with obtaining reasonable throughput for these separations has been the only, albeit overwhelming, obstacle preventing widescale use of these methods. Attempts to devise continuous (cheaper) systems have previously resulted in moving, or simulated moving, beds of resin with complicated valving and timing sequences. These disadvantages, plus technical problems associated with the disturbing effects of non-plug flow and reduced resolution of moving versus packed beds, severely limit applicability of these systems. Over the past decade a new device has been developed that overcomes many of these problems. It utilizes a slowly (less than one revolution per hour) rotating annular bed of sorbent material with fixed-feed inlet and product withdrawal points. Numerous units of various diameters and lengths have been fabricated and operated, and a parallel effort has developed a satisfactory theoretical treatment of the device. Several simple control systems have been incorporated to thoroughly demonstrate the simplicity of operation, even for multiple products and multiplecarrier flows. This device has been developed using several metal solutions and has demonstrated its power with some of the most difficult, including the zirconium-hafnium, separations. Design equations are available for sizing units based on simple laboratory data and have been tested for units as large as 18 in. in diameter.

Jan 1, 1985

By Paul D. Tomlingson

World class performance is the ultimate objective of many maintenance organizations. It marks the organization as a leader in its industry and sets it apart as the ultimate achiever. But what is a “world class” standard and how can it be achieved? Is there a yardstick by which an industrial organization can measure the relative performance of its maintenance activity and compare it with performance levels that universally identify “world class” status? Are there financial formulas, achievements, evaluation techniques or indices that provide this yardstick?

Jan 1, 2006

Peru has become an established mining country. The industry and industry-related businesses account for a significant amount of the country´s revenue, on state and local levels. But like other countries with thriving mining industries, Peru has seen its mining industry revenues fall off in recent years due to a lackluster global economy. And the mining industry in Peru must also deal with increasing concerns about mining?s environmental impacts, local community and other social issues, as well as a regulatory environment that has placed more restrictions on what miners can do. That said, the Peruvian government is beginning to realize how important mining and natural resource development is to building the nation?s economy, improving its infrastructure and lifting its population out of poverty. The government support was evident during the Perumin 2013 mining convention, held in September in Arequipa. In addition to Peru?s President Ollanta Humala speaking at the closing ceremony, the country?s ministers of Energy and Mines, and Economy and Finance participated in the event, as well as numerous other federal and state authorities. Perumin is put on by the Instituto de Ingenieros de Minas del Peru (IIMP, or Peruvian Institute of Mine Engineers). The 31st edition of the convention, billed as the ?world?s largest mining convention? by the IIMP, this event was led by Abraham Chahuan CEO of Antamina and Romulo Mucho (SME member) as president of IIMP, attracted about 118,000 participants from more than 48 countries. This was more than the anticipated 75,000 attendance and well past the 51,000 people who attended the 2011 convention. The last edition of PERUMIN was led by the CEO of Compañía Minera Antamina, Abraham Chahuan and Rómulo Mucho (SME member) and representative of the IIMP. The event attracted more than 1,000 journalists from all over the world, the IIMP said. A total of 2,213 booths from equipment and machinery supplying companies from the five continents were present at the Mining Technology Exhibition (Extemin), including companies from the United States, Canada, China, South Africa, Germany, Australia, Brazil and Chile, among others. The convention has grown so large in recent years, that the IIMP shifted its location from Tecsup vocational school in Arequipa to the Cerro Juli Convention Center. The venue is 116 percent larger than Tecsup, the IIMP reported, covering about 20 ha (40 acres). It was reported by Latinomineria magazine that about 10 million Peruvian soles were invested in the new venue to create a world-class events center. It was also estimated that the event generated more than 234 million soles to Arequipa?s economy.

Feb 1, 2014

By E. Sirolli

In recent times, with rare exceptions, most economically viable ore discoveries have been large, low-grade and located in remote parts of the world. Mining companies have often shown to be incapable of mitigating their social and economic impact on local communities. Sustainable development and relations can be achieved by implementing bottom-up methodologies to the top-down tools already in use by mining companies. In order to magnify the importance of enterprise facilitation as a primary method for community development, data from 25 years of community based work around the world was used. Results highlight the need for a grassroots approach to local economic and community development, which focuses on the creation of a parallel economy in communities. Using solely top-down methodologies for developing community relations is shown to be a limited resource for mining companies. There are fundamentally two dangers for mining companies: alienating the local population, resulting in militancy and lengthy legal battles to obtain a license to operate; and, being accountable for building social and economic infrastructure that are not the company?s responsibility.

Jan 1, 2012

By Raymond A. Bradbury

Martin County Coal Corporation&apos;s operations are located on Wolf Creek in Martin County in the eastern part of Kentucky. The mining complex was started in 1971 and has grown to a 2.273 Mt/a steam coal operation. All of the production goes to Duke Power Company&apos;s Belews Creek electric generating station in North Carolina. Production comes from four seams that are mined by deep and surface mining methods. Surface mining accounts for 55% of the production and the remainder comes from 2 underground mines. Continuous miners are used exclusively underground. The preparation plant was originally designed to take coal at the rate of 907 Mt/h but that has gradually been increased to 1134 Mt/h. Other cleaning equipment includes Daniels DMS vessels, Model 77 Deister tables, 355.4-mm R. & S. Hydro- cyclones, Krebs 254-m classifying cyclones, Daniels froth cells and in 1980, 3 Krebs 508-mm heavy media cyclones were added to recover some lost and misplaced material. CMI centrifugaldryers and a Hey1 & Patterson size 100 thermal dryer are also part of the coal preparation equipment.

Jan 1, 1981

By Henry S. Brown

At least two dozen massive sulfide deposits in the southern Appalachians have supported significant mining operations. Literally hundreds more deposits are known to exist, but are too small to be of commercial interest. Essentially all that are being, or have been, mined are those deposits that were exposed at the surface when first discovered. It is reasonable to assume that many more massive sulfide deposits, large and small, exist hidden not far beneath the surface. The ideas I am sharing with you here today are based both on my personal studies of some of the deposits and on descriptions of deposits in the literature. An attempt will be made to account for the genetic interpretation problems raised by many of these deposits posessing both "syngenetic" and "epigenetic" features. In addition, an examination will be made of the possible relationships between the massive and the not-so-massive sulfide deposits in this region. Hopefully, these observations added to those of others will eventually lead to the synthesis of a better model on which we can base exploration programs in the southern Appalachians.

Jan 1, 1976

By MYRIAM FRANCOEUR, JOHN R.R. BOWLING, ADAM MCFADDEN

As duct-fan systems push the envelope of power, length and cost, their design calls for a more comprehensive technoeconomic analysis to ensure they deliver the expected results without failure and cost overrun. This work explores the numerous factors to include in the design of an extensive (semi-)rigid duct-fan system. Besides delivering a given airflow, the system must satisfy component limitations and power constraints during its lifetime. We evaluate the assumptions underlying the positioning of in-line booster fans in a long gapless duct-fan system and propose a strategy for specifying the location and blade pitch of successive booster fans to prevent system failure due to a partial vacuum.

Oct 1, 2022

By R. N. Gow

Acidic treatment of enargite (Cu3AsS4) dissolves both arsenic and copper from the mineral and then attempts to separate them in the leach solution. The reactivity of enargite was examined in acidic solutions, over the pH range 1-7, to determine a potential range for co-dissolution.. Enargite mineral samples from Butte, MT and Quirivilca, Peru were used as working electrodes in a cyclic voltammetry corrosion cell setup, which were then cycled multiple times over -1000 to 1000 mV. Surface reactions and transitions were characterized using in-situ Raman spectroscopy, which were then compared to updated predominance diagrams for the copper-arsenic-sulfur system from a previous study done under alkaline conditions. The region of co-dissolution is limited to > 600 mV vs. SHE and pH < 1 under the proposed diagram.

Feb 23, 2014

By Steven W. Hunt, Safdar A. Gill

Design and construction of temporary shafts for underground facilities often require evaluation of bottom stability due to rupture (blow-ins) caused by water pressure acting on a bottom plug. This paper provides an overview of shaft bottom stability evaluation methods for the case of a relatively watertight soil plug which overlies an artesian aquifer. Methods of considering plug perimeter shear, plug buckling and pressure relief are discussed. Minimum factors of safety are suggested. Future use of the shaft subgrade is also considered. Bottom plug failure case histories at several shafts are evaluated. This paper should be useful to project designers, ground support system design engineers and contractors involved with construction of shafts for underground facilities

Jan 1, 1997

By L. Adler

In spite of distractions from glam-our areas (ground control, computers, etc.), excavating and bulk handling in mining remains paramount but is now undergoing dramatic advances. The massive intervention of mining and civil engineers as "engineer-users" into the tight, exclusive, and specialized bond between the equipment operator ("operator-users") and the manufacturer (mechanical engineers "and sales "reps") has now occurred. Three developments have accelerated this: 1) larger, more costly, complex, specialized, and innovative equipment; 2) a more profound understanding of the equipment, operations, and working conditions (encumbered space); and 3) a concurrent thrust into "high-tech," (automatic and remote controls, sensors, automation, artificial intelligence, and even robotics) and human factors (workload intensity, work-station design). This has produced a well-defined professional discipline, including construction and even military engineering. The mine plant, and to a lesser extent, the mine face, is now being monitored. Equipment conferences, journals, and centers at universities and agencies have multi-plied. The discipline&apos;s impact on future mining now becomes more apparent.

Jan 1, 1988