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By Richard E. Lounsbury

Coal mine refuse handling traditionally has been the redheaded stepchild of the industry - a problem to be ignored as much as possible. During the past few years, however, mining companies have become more aware of the potential water pollution problem associated with refuse handling and storage. Planning for refuse disposal increasingly emphasizes protection of the environment as well as economics of refuse handling. Coal companies are responding to the environmental control needs by devising new systems and adapting well-known techniques to refuse handling systems. Monterey Coal Company has operated a non-polluting refuse disposal system at its No. 1 Mine for over two years. The purpose of this paper is to describe the design considerations given to the planning of that system and the operational experience gained during its construction

Jan 1, 1973

By F. Habashi

Chile is at present the largest copper and rhenium producer and was before World War I the largest nitrate producer. She is also an important producer of lithium carbonate and molybdenum oxide. An important event in the history of the country is the Pacific War of 1879-1883 in which she acquired the northern provinces initially belonged to Bolivia and Peru. In 1888 Chile annexed Easter Island. The Chilean mineral and cultural history is briefly reviewed together with the people who contributed to her development. The present report is the result of a number of academic and industrial visits to Chile during the period 1992 to 2009.

Jan 1, 2011

By C. S. Compton, T. E. Marshall, D. R. Dolinar, R. Grau, L. J. Prosser, A. T. Iannacchione, D. C. Oyler

Unrecognized roof beam failures resulted in 69% of the falls of ground injuries occurring in underground U.S. stone mines from 1990 to 1996. Field investigations at 45 underground stone mines suggest that excessive beam sag or deflection is the principal unstable roof behavior characteristics associated with miner injuries. Laminated roof structures, common in most underground stone mines, allow the immediate roof to separate into distinct beams. The timely determination of roof beam deflection could provide stone miners with advanced knowledge of potentially hazardous roof. Existing methods to assess roof conditions consist of observational and monitoring techniques. Observational techniques include open drillholes, sounding, wedging, and borescopes. Monitoring techniques include scratch tools, extensometers, telltales, Miners Helpers, and Guardian Angels1. Miners have difficulty utilizing these techniques because roof beams are located an average of 8 m(26.5 ft) above the miner’s head in environments that are dark, dusty and noisy and these deflections are measured in millimeters of movement. To help mitigate the potential for falls of ground injuries to underground stone miners, the National Institute for Occupational Safety and Health (NIOSH) has developed the Roof Monitoring Safety System (RMSS) to aid in monitoring dangerous levels of roof beam deflection. If enough site-specific information is collected and placed on highly visible maps, individual mining operations could establish general guidelines for responding to specific roofbeam deflection occurrences. This would help in implementing a pro-active, comprehensive roof control plan for reducing falls of ground injuries.

Jan 1, 1999

Introduction Agrico Mining Co.'s Florida mining division has three surface mines and employs nearly 700 workers. The division produces some 6.3 Mt (7 million st) of phosphate rock annually. It is a good business. And Agrico has made it better by making it safer through a new approach to mine safety. In one year, Agrico - the second largest phosphate mining company in the US - recorded a stretch of one million manhours without an accident. That same year, the direct cost of accidents dropped to $9137 from a previous five-year average of about $50,000. Together with Don Roe, division manager of safety and security, Division General Manager Don Morrow made 1981 a watershed year for safety at Agrico. Morrow called on consultants from Safety Management Services of Du Pont's Specialty Services division to strengthen a safety program that was already better than average. From the late 1970s and into 1981, lost-workday cases (LWCs) were costing Agrico an estimated average of $22,000 each. And they were occurring with alarming frequency. In 1977, the company recorded six LWCs at an incidence rate of 0.64. This was followed by a jump to nine cases in 1978. In 1979, both occurrences and the rate increased - 10 LWCs at a 1.19 rate. The number of LWCs decreased to seven in 1980, with a rate of 0.71. Agrico instituted a far-reaching safety program in 1981, which began to take full effect in 1982. LWCs dropped from five in 1981, to three in 1982. And the direct cost plummeted from $110,346 to $28,828. In 1983, the mines recorded only one LWC. Its $9137 cost represented a reduction of $101,209 since the Safety Management Services of Du Pont had been called in. Through early 1984, the LWC incidence rate at the facility's three mines, phosphate drying plant, and transportation department was down to 0.26. This is 84% lower than the 1982 mining industry average, making it the safety leader among all Agrico companies, including its chemical plants. New Approach Agrico had the basics of a safety program in place when the Du Pont consultants arrived. But Du Pont suggested changes in responsibilities and company philosophy that formed the foundation of

Jan 1, 1985

By Donald W. Gentry

This paper presents some of the results of a rock mechanics in¬strumentation program designed for, and implemented at, longwall panel 4N at the York Canyon Mine near Raton, New Mexico. The objective of this particular instrumentation program was to determine the response of the rock mass to longwall mining of a thick coal seam utilizing shield-type supports. Measurements were made in the rock along the ground surface, above the coal seam, in the coal seam and immediately below the coal seam. Longwall test panel 411 had a total developed length of 762 m (2500 ft) and a face width of 168 m (550 ft). The seam mining height in the panel area was approximately 3 m (10 ft). The average depth of overburden above the panel is 107 m (350 ft) al¬though it ranges from 73-134 m (240 - 440 ft). Roof support at the face was provided by Hemscheidt shields. These shield-type supports weigh 11.4 metric tons each.

Jan 1, 1977

The mining and minerals extraction industries have often been demonized by the public as industries that put profits and production before people. It is true that the inherent danger of the work has led to more fatal accidents than anyone associated with the industry would care to remember. But, in stark contrast to what has often been said, the truth of the matter is safety is now the top priority of every miner, from the face of the longwall to the executive boardroom. Without safety, nothing else matters. This message was told and retold by representatives from some of the world?s top mining and petroleum companies from Oct. 11-13 during the inaugural Safety and Reliability in the Mining and Resources Industries Conference in Calgary, Canada. The meeting was hosted jointly by the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) and the Society for Mining, Metallurgy, and Exploration (SME). It was the first of a series of conferences to focus on these important topics. Next year, the conference will be held in Minneapolis, MN from Nov. 13-15.

Jan 1, 2011

By E. W. Sawyer

Attapulgite is a magnesium aluminosilicate clay mineral which exhibits unique, processing-enhanceable physical and chemical properties that are related to its current commercial uses. Properties of commercial interest are gelling, absorption, adsorption, binding, acid neutralization and many others. Major industrial applications are: (1) absorption by heat treated grades utilized in industrial oil and grease absorbents and in agricultural pesticide carriers; (2) gelling of aqueous liquid products by colloidal grades for stabilization and viscosity control in salt water drilling fluids, suspension fertilizers, liquid animal feed supplements, paints and tape joint compounds; (3) adsorption by heat treated varieties for the removal of catalysts, color bodies and other polar compounds from hydrocarbon streams; (4) gelling of organic liquids by colloidal attapulgite/surfactant blends in oil-type paints, fibrated and nonfibrated asphaltic coatings and mastic compositions, and (5) the binding of feeds and molecular sieve sorpents with colloidal type attapulgite products. These applications and other less common uses and potential uses will be discussed along with, the necessary selective mining and plant processing features related to each property and application.

Jan 1, 1986

By N. Ripepi

"The Langmuir model has been widely used for the coal-methane sorption process via an isothermal test. However, even though the temperature-dependent Langmuir model were recognized theoretically and experimentally, the quantitative relationship between the Langmuir’s constants (a & b) and temperature have not been clarified and confirmed by lab test data. This paper collects 158 methane-coal sorption data under different temperatures, which apply the Langmuir model to consider the relationship between Langmuir’s constants (a & b) and temperature (see APPENDIX I). Even though the Langmuir model cannot be used to show the physical state of methane adsorption on coal, it is widely used because of its simplicity and the reasonable explanation of its parameters (a & b). The results from these published isothermal tests confirm that 1) there is no consistent relationship between Langmuir’s constant-a and temperature; 2) the Langmuir model is a temperature-dependent model, and the temperature-dependent feature is mainly shown by the relationship between Langmuir’s constant-b and temperature; 3) The relationship between Langmuir’s constant-b and temperature can be described by both the exponential and linear relationship with dried coal. This paper provides a database for temperature-dependent Langmuir’s model, which can be used for reservoir simulation of coalbed methane reservoir, coal seam degasification modeling for underground coal mines considering the heating effect induced by geotherm and heat injection (via hot water, hot steam, ultrasonic, etc.). INTRODUCTION The isothermal test for gas sorption on coal is one of the fundamental tests in Coalbed Methane (CBM) recovery fields, such as underground coal mine methane degasification, CBM gas-in-place estimation, and carbon dioxide sequestration in un-minable coal seams. Generally, two methods, volumetric and gravimetric, are employed to obtain isothermal data (Bush, A. & Gensterblum, Y., 2012). Based on these two approaches, a series of commercial and self-assembled instruments are built and several calculation methods are used to obtain isothermal data (Bush, A. & Gensterblum, Y., 2012, Gasparik, K., 2014; Goodman, A. L., et al, 2004; Zhang, L., et al, 2013). In the post-processing stage, many models are provided to analyze isothermal data in order to understand the storage mechanism of gas in coal. Common models include the Langmuir model (and its extended forms), the pore-filling model, multilayer adsorption model (BET), and the Gibbs’ model. Among these models, the Langmuir model is the most widely used for its simplicity and functionality. The Langmuir model is expressed as follows:"

Jan 1, 2016

By J. S. Jaspal

Mining of thin coal seams is both difficult and uneconomical. As a result, most of thin-seam coal reserves in the U. S. are not being mined. It is estimated that nearly 910 Gt (K. Unrug, 1985) of coal reserves exist in 355 to 710 mm thick seams. The Bureau is attempting to develop new techniques for mining 150 to 1065 mm thick coal seams. This paper summarizes the research work on existing thin-seam mining techniques, testing on small and full scale physical models of the Bureau slot mining concept, and computer modeling of the full-scale process.

Jan 1, 1992

By Peter W. Scott

Feldspars have major uses in glass manufacture and in ceramic products. About 6 million metric tons (6.6 million short tons) are used annually. Feldspars are desirable because of their high aluminum and alkali contents. Na feldspars are favored for glass, while K feldspar is often preferred in the pottery and tile industries. Economic deposits occur in a variety of geological environments. Most are in granites or granite-like bodies, pegmatites being a common source worldwide. Alkali granites, particularly those some- times called alaskites, are mined directly as a source of feldspar and associated minerals. Some other igneous bodies, such as aplites, rhyolites, and partly altered granites (for example china stone) provide alternative feldspar-rich products. Nepheline syenites and phonolites are other sources of feldspar and contain higher amounts of alkalis. Feldspar-rich (arkosic) sediments derived from the weathering of pegmatites and granites are widely extracted and processed for use in ceramics. The present study reviewed the various sources of feldspars throughout the world. Data on the quality of products has been taken from literature, and samples have been obtained from a large number of producers. The mineralogy and chemistry of the samples has been determined and, as far as possible, have been related to the geology of the source area. Feldspar products show a wide range of chemical and mineralogical compositions. Some are pure Na feldspar (albite), others are made up entirely of K feldspar (microline and orthoclase), but many are mixtures of Na and K feldspars. Significant quantities of quartz are often present, and many products contain mica and kaolinite. Fe203 con- tents are very low, typically less than 0.1 percent. Detailed mineralogical studies show that four groups of products can be recognized on the basis of feldspar mineralogy. These are albite, albite with microcline, microcline with orthoclase, and orthoclase with albite. Products containing microcline and orthoclase together are mostly sedimentary in origin. Those with albite only, or albite with microcline have a pegmatitic or granite origin. Those containing orthoclase as the dominant K feldspar are derived from aplites or rhyolites. There does not appear to be any relationship between the feldspar mineralogy and the quartz content. Peraluminous S- type granites and pelite-dominated high-grade metamorphic rocks, in which there is a significant volatile component, are likely to be the most important feldspar sources. Partial kaolinization of feldspar-containing rocks often improves minability, decreases crushing costs, reduces iron content, and increases the K2O/Na2O ratio.

Jan 1, 2001

By R. G. Darmody

Longwall coal mining in southern Illinois occurs beneath some of the best agricultural land in the U.S. This region is characterized by highly productive, nearly level, and somewhat poorly drained soils. Subsidence from longwall mining causes changes in surface topography which alters surface and subsurface hydrology. These changes can adversely affect agricultural land by creating wet or ponded areas that can be deleterious to crop production. While most subsided areas show little impact from subsidence, some areas experience total crop failure. Coal companies are required by law to mitigate subsidence damage to cropland. The objective of this study was to test the effectiveness of mitigation in restoring grain yields to their pre-mined levels. The research was conducted on sites selected to represent conventional mitigation techniques on the predominate soils in the area. Corn (Zea mays L.) and soybean [Glycine max.(L.) Merr] yields in 1988, 1989, 1990, and 1991 from mitigated areas were compared to yields from nearby undisturbed areas. There was no significant (a=0.05) difference in soybean yields averaged over the four years. Average corn yields, however, were significantly lower than reference areas. The impact of subsidence and mitigation is variable and site specific. Results were also related to weather. In wet years, yields in mitigated areas tended to be depressed. This research demonstrated that mitigation of subsidence damage can be successful.

Jan 1, 1986

By Robert C. Maxton

The foundry industry is a basic source of structural component for all industry. Millions of tons of castings are produced annually in both ferrous and nonferrous alloys. These castings are subjected to a wide variety of heat treatments, finishing techniques, mechanical tests and machining operations. Through all of these steps the quality of the casting is of paramount importance to the end use of the product. The Quality Assurance Program at Minneapolis Electric Steel Castings Company is designed and established to provide a superior product for both original equipment manufacturers and the mining industry.

Jan 1, 1982

By Joe B. Rosenbaum

Fine-sized mineral wastes discarded by ore milling plants require stabilization to prevent air and water pollution. Methods devised for achieving this stabilization include physical, chemical vegetative, and combination procedures. Although vegetative reclamation is preferred to physical and chemical stabilization, it is difficult to achieve because the wastes are sterile, contain deleterious inorganic salts, and lack the essential nutrients and physical characteristics required for sustaining vegetative growth. Nevertheless, recent research has developed methods for producing vegetative growth on all but excessively acidic, basic, or saline tailings at costs ranging from $100 to $650 per acre. This report summarizes effective procedures developed for vegetating average tailings, the cost differential between the various methods, and suggests procedures that may be applicable for achieving stabilization of pyrite-containing wastes that may oxidize and become excessively acidic. The use of buried layers of sewage sludge to prevent this acidification is discussed.

Jan 1, 1972

By Xiyu Gao, Yi Yang, Mark I. Pownceby, Shuiping Zhong, Miao Chen

In the present study, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray absorption near edge structure (XANES) spectroscopy, and Raman spectroscopy were used to investigate the effect of chloride ions on chalcopyrite bioleaching and chemical leaching at 25 °C. The leaching results show that the addition of chloride ions suppressed the dissolution of chalcopyrite in both chemical and bacterial leaching. In chemical leaching, the solution redox potential in the experiment without Cl− stayed in a range more suitable for chalcopyrite dissolution compared with experiments with Cl− . In bioleaching, the bacteria activity was suppressed by Cl− leading to low dissolution rates of Cu. Surface morphology and chemical speciation studies confirmed the formation of potassium jarosite on the surface of the chalcopyrite leach residues. In addition, S K-edge XANES indicated the formation of trace amount of elemental sulfur and covellite on the mineral surfaces.

By Raymond W. Peterson

The practice of Countertrade and all of its variations has increased dramatically during the last five years in great part due to the worsening world economic situation and the Third World's increasing debt problems. Conventional wisdom has held that the goods finding their way into countertrade will tend to be manufactured goods of ever increasing value added. It is my contention that this has not been the case. The continued depression of most metals and minerals prices has conspired to keep a great number of metals and raw materials in the forefront of countertrade negotiations. The concept that if a country needs hard currency it will simply sell metals into world markets for cash has been significantly modified by countertrade which encourages subsidies for raw materials which are in turn funded by higher prices for the manufactured goods which the country must import. Countertrade is a term that is relatively new to most of us who have been involved in the international trade of metals and minerals, but it is one that we will continue to hear more of in the future. Countertrade as it is generally known today had its beginnings after the Second World War in Eastern Europe. As the shattered economies of Europe struggled to right themselves, a "cashless" system of trade developed. This system included such ancient concepts as barter as well as more modern ones like bilateral clearing agreements. For over 30 years countertrade was confined mainly to the COMECON nations and their various trade protocols with Third World nations. If metals and minerals were involved, there was little disruption of world markets by such examples as Cuba shipping ferronickel and sugar cane to the U.S.S.R. for a host of manufactured goods and oil. As the world's economy began to slow in the late 70's and the debt crisis began in earnest in the early 801s, this all began to change. As more and more nations which had previously been almost totally dependent upon their mineral wealth over-extended themselves in an attempt to industralize, they concurrently found their income from minerals falling, due to the decreased demand and subsequently lower prices available in the marketplace. At first these nations attempted to balance their payments by promoting the sales of their high value-added manufactured goods. We have all heard numerous examples of U.S. companies going to sell their high technology products in Rumania or Yugoslavia and being confronted with counterpurchase requirements for machine tools, shoes or drill bits. When faced with these demands, a number of companies chose not to sell into those markets while others merrily signed up the obligations without much intent to carry them out. The Performance Bonds required were generally minimal, especially when considered in light of the high margin inherent in high tech items; and the penalty clauses were equally small or nonexistent. A third group of companies actually tried to buy the machine tools or drill bits either for their own internal use or resale but found that due to poor quality and high prices, they were faced with a difficult if not impossible task. This is not to say that no one was able to fulfill a countertrade requirement, but the success ratio on these transactions was incredibly low. This was one of the major contributing factors to the reputation that countertrade has gained as a discipline ... "that it is mostly talk and very little action." As this situation slowly evolved, both the countries imposing the countertrade obligation and the exporters assuming the obligation began to realize that something

Jan 1, 1986

By Gary Brierley, Lok Home

"The majority of tunnels for civil engineering applications are now being constructed using some form of mechanical excavation. Beginning in the 1960s with rock tunnel boring machines (TBM), the tunneling industry has introduced both earth pressure balance (EPB) and slurry pressure balance (SPB) soil machines; mixed soil and rock machines and a variety of different mechanical devices for the construction of small diameter tunnels. Over time, these machines have become more powerful and more adaptable to a wider variety of ground conditions; so much so that tunnels are now being constructed in ground conditions and in the vicinity of third-party impacts that would have been considered beyond the state of the art just 10 years ago. Figure 1 is an example of a mixed ground crossover TBM used successfully at Mexico City’s Túnel Emisor Poniente II.All of the above is highly advantageous for the tunneling industry, but it has also placed a much higher level of risk on the performance characteristics of the tunneling machines, on the contractors operating those TBMs and on the manufacturers of those machines. Most of the risks for a tunneling project are associated with creating the space inside of which the finished facility will be constructed. In order to create that space, the tunnel contractor must make many decisions about the best way to excavate the ground, the best way to control the ground at the face of excavation and the preferred method for supporting the ground around the tunnel in a manner that is safe for the workers and stable with respect to all of the overlying and adjacent existing structures. If it is proposed to use some form of TBM in order to build the tunnel, then the TBM becomes central to all three of these activities and becomes an integral part of managing the risks associated with these activities."

Jan 9, 2018

By Y. Akin, M. Hancer, M. S. Celik, J. D. Miller

Flotation pulps with boron minerals such as colemanite and borax using primary amine collectors, e.g. dodecylamine, exhibit collector precipitation above a critical pH depending on the amine concentration. This was earlier attributed to the formation of a mine hydroborate. However, results from this current study indicate that the precipitate is dode-cylamine, rather than dodecylamine hydroborate. A systematic study involving solubility, zeta potential, microflotation, adsorption, and surface tension measurements is presented to elucidate the role of a mine precipitates in boron flotation systems.

Jan 1, 2000

By Michael Edesess

The salt gradient solar pond has been the focal point of accelerating international attention and interest in recent months. Only recently have most investigators in the renewable energy field come to realize the versatility of the solar pond, and its ability to overcome certain problems usually associated with solar technologies. These realizations, together with clear demonstrations in Israel and elsewhere of its technical feasibility, have combined to bring the solar pond to the forefront of renewable energy technologies. The solar pond is a natural or site-built pond, about one to five meters or more in depth, which has been altered to retard the loss of absorbed solar energy. The absorbed solar energy is usually lost through upward buoyancy of the warmed water, followed by the loss of its heat to the atmosphere. The chief solar pond technology -the salt gradient, or "nonconvective" solar pond-prevents this upward buoyancy by means of a vertical density gradient achieved with dissolved salt. The deep waters in the solar pond reach high temperatures, up to and even above the boiling point of pure water.

Jan 1, 1981

By B. Berg, J. Stephenson, J. Mansanti, C. Nyikos

"Intrepid Potash, Inc.’s Carlsbad East facility has refined sylvite and produced muriate of potash (MOP) since 1965. In addition to MOP, Intrepid Potash began recovering the mineral langbeinite from a mixed ore reserve in 2005. In 2011 a new langbeinite recovery process for the coarse (+850 micron) size fraction was constructed to enhance the overall langbeinite recovery. Based on the limited mixed ore reserve and an abundance of langbeinite ore reserves the transition of the East plant to a langbeinite only facility was targeted for 2021. Due to a decreasing grade of the mixed ore reserve, declining sales pricing, and high sylvite operating costs a strategic decision was made to accelerate this transition into 2016. To enable a successful transition, a fines recovery system needed to be developed, constructed and implemented. This paper describes the advancement of langbeinite processing at Intrepid Potash and the planning, development and successful execution of the transition to a langbeinite only operation. BACKGROUND Langbeinite (K2SO4·2MgSO4) is a double salt containing potassium sulfate (K2SO4) and magnesium sulfate (MgSO4). It is used as fertilizer and in the industry is described as Sulfate of Potash Magnesia. It is attractive as a specialty fertilizer and in addition to containing a ready source of a primary nutrient potassium, it also provides two secondary essential nutrients, magnesium and sulfur. It is especially attractive for chloride sensitive crops. Langbeinite has a specific gravity of 2.8, a Mohs hardness of 4.2, and is brittle thus very friable. It is the hardest of the saline minerals, and despite its relative softness on the Mohs scale can be very abrasive in process environments and in field applications, probably due to its conchoidal cleavage. Its solubility at 240 g/l is less than the solubility of sylvite (KCl) or halite (NaCl) and due to even slower relative dissolution kinetics washing with cold water has been a common practice for upgrading langbeinite ores. The solubilization/crystallization relationship for langbeinite is different from the majority of other evaporite minerals in that once langbeinite is solubilized it does not form langbeinite again. Instead it gives up one mole of magnesium sulfate, takes on various waters of hydration and precipitates out as either schoenite (K2SO4·MgSO4·6H2O) or leonite (K2SO4·MgSO4·4H2O) depending on temperature. Due to its partial solubility and phase transitions at its surface when exposed to moisture, there is strong cohesion between wetted particles; the resulting stickiness of the upgraded products can create significant materials handling issues unless processed in slurry form or at relatively low moisture levels. Langbeinite has been produced commercially from two locations, the Kalush and Stebnik regions in the Cartpathian Mountains of former Poland and now the Ukraine and from the Permian Basin in New Mexico (Garrett, 1996; Smith 1949). Current production is from two operators in the U.S., Mosaic and Intrepid Potash."

Jan 1, 2017

By P. J. Ryan

Phelps Dodge’s Candelaria copper-gold mine is located 20 km (12miles) south of Copiapó in northern Chile’s Atacama province (Region III) (Fig. 1). The Candelaria Mine is about 800 km (500miles) north of Santiago and 75 km (47 miles) east of the Pacific Ocean. Its elevation is 600 m (1,970 ft) above sea level. The Copiapó River Valley is 6 km (4 miles) northeast of the mine site. It is the only major source of water in this arid region. The average rainfall is 14mm/a (0.5 in./year). During 1995, the mine produced 521.4 kt (574,800 st) of copper concentrate containing 150 kt (165,000 st) of salable copper and 3 t (98,800 oz) of gold. The 1995 unit cash cost was less than 50 cents/lb of copper. This makes Candelaria one the world’s lowest cost copper producers.

Jan 1, 1996