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By K. L. Myers, R. Espell, C. Deringer

Construction of the AA Pad reclamation was completed in the fall of 2000. Seeding of the ET cover began in the late fall of 2000 and continued through May of 2001. On Saturday afternoon, June 1, 2002, a large, very localized thunderstorm struck the reclaimed AA Pad site. Eyewitnesses present at the time described a dark storm cloud parked above the site for less than half an hour. Average rainfall intensity was measured to be 122 mm (4.8 inches) per hour and peak rainfall intensity was estimated to be 213 mm (8.4 inches) to 259 mm(10.2 inches) per hour. At the time of the storm, the construction was less than two (2) years old and the vegetation had only a single season of growth. The entire period from the end of construction until the date of the storm was a drought period with below normal precipitation. Other than a few small snowmelt events, there was no precipitation event large enough to produce any significant flow in the channel network. Therefore, the very first significant runoff event was the extreme event of June 1, 2002. The storm essentially represents a large-scale field test of the design concepts used at the AA Pad site. Shortly after the storm, data was collected and analyzed with the intent of learning as much as possible about the performance of the cover system design with the expectation that the newly acquired knowledge might be utilized in future designs to further improve the performance of similar cover systems during extreme events.

Jan 1, 2003

By J. D. Miller

Many factors -- political, environmental and technological -- will determine the extent to which the United States realizes the potential of its vast coal resources. Not the least of these factors is technogical development including mining, processing and transportation. With regard to processing technology, about 50% of the 800x106 tons of coal mined annually in the U.S. is processed in preparation plants. The purpose of the physical separations accomplished in these preparation plants is to remove ash (present as clays and other oxide minerals) and sulfur 'present mostly as pyrite). Coal flotation circuits for such separations are becoming more important in the processing of minus 28 mesh coal. (1,2,3) For example in the U.S. in 1960, 31 flotation plants processed 26,500 tpd; whereas in 1980, there were 80 flotation plants which processed 78,300 tpd. This corresponds to an annual growth in flotation plant capacity of 10 per year during the past two decades. Coal flotation is based on the natural or induced hydrophobicity of coal particles which are separated from hydrophilic ash and sulfur constituents by attachment to air bubbles. The coal particle/air bubble aggregates are collected in a froth phase which is created by the addition of a suitable frother such as MISC. Without exception, such separations are made in a conventional flotation cell, which, in essence, is a stirred tank reactor with a shrouded rotor to shear the air as it passes through a hollow shaft. The dispersed air bubbles (4.0 mm diameter) are stabilized by addition of the frother. Collision of the air bubbles with, and/or precipitation of the air bubbles on, the coal particles results in the formation of coal particle/air bubble aggregates which rise in the gravitational field and are collected in the froth phase developed at the top of the flotation cell. Restraints on successful separation by this conventional flotation technique are particle size and retention time. Generally it is found that effective flotation is only achieved for particle sizes between 10 and 1000 microns. Further, with respect to retention time, it is found that a nominal retention time of at least 2 minutes is required for successful separations. These facts limit the effectiveness of conventional coal flotation. Coal fines may be lost in the reject stream and disposal is frequently a problem. The retention time required for conventional flotation results in large floor space demands which limit the capacity of the plant.

Jan 1, 1981

By R. A. Franks

An evaluation of a nuisance-emissions-discriminating smart mine fire sensor system was made in an operating coal mine. These field evaluations were conducted to determine the sensor system?s ability to discern nuisance emissions, such as diesel exhaust, emissions from flame cutting and welding operations or hydrogen gas from a charging station, from real fires and to compare the number of falsely reported fire alarms generated between the sensor system and a standard carbon monoxide (CO) monitor. The sensor system?s ability to operate successfully in the working environment of an operating coal mine was also evaluated. The smart mine fire sensor system consisted of four sensors whose data outputs were fused with the use of a neural-network-type computer program. Long-term trials were conducted in a haulage way, a belt entry, and a track entry. The system functioned successfully in the belt entry, in accordance with its developmental goals, where the sensor system even discriminated events not anticipated during development. It was not totally effective in the haulage way and track entry, though, due to a combination of significant diurnal air temperature variations, dust, and mechanically induced vibrations. Also, deteriorating rib conditions contributed to operational problems in the haulage way evaluation. In general, the smart mine fire sensor provided nuisance emissions discrimination and was shown to be a viable new approach for mine atmospheric monitoring, enhancing miner safety. This paper describes the in-mine evaluation of the smart mine fire sensor system and discusses recommendations for improving the system. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2008

By B. Ballard

Engineers at a West Virginia coal preparation plant owned by one of the nation's largest coal producers sought a fire suppression system for the plant's MCC and cable spreading rooms. Officials considered the traditional options of water-based sprinklers, dry chemical, and clean agent systems; however, each of those options presented challenges. Sprinklers can damage electrical equipment, proper delivery of the agent and adequate coverage/protection can be an issue with dry chemical systems, and clean agent systems require room integrity. An alternative to traditional systems was discovered in the Victaulic Vortex Fire Suppression System. The first hybrid inert gas/water mist system (FM 5580), Vortex adequately addressed these concerns. The system, which deploys a high-velocity, low-pressure mixture of water and nitrogen, is not damaging to electrical equipment and extinguishes fires in open, ventilated areas. This is one of the first installations of the Vortex system in a prep plant, and is a compelling example of how new technology can overcome the challenges of traditional technologies. The paper will detail plant specs, situation, and system evaluation, selection, and configuration.

Feb 23, 2014

By S. K. MONDAL, K. K. K. SINGH, S. Singh, R. K. TIWARY, S. K. Chaulya, G. C. MONDAL, R. S. Singh, T. B. SINGH

In this work, a comprehensive field study was carried out to measure the background air quality status and identify the air pollution sources from opencast mines around a heritage site in India. Air quality modeling was conducted to envisage dust concentration due to existing and closed mines in the region. The air quality modeling exercise predicted that particulate-matter levels of PM10 and PM2.5 might increase in the ranges of 3.2 to 23.1 and 2.1 to 8.9 μg/m3, respectively, due to mining activities when some of the closed mines will be operated in the region without controlled emission. The predicted total PM10 and PM2.5 at the selected receptor locations were in the ranges of 86.39 to 194.89 and 34.82 to 99.55 μg/m3, respectively. Adequate measures were suggested to control air pollution from mining activities, and an intelligent dry fog system was designed to suppress dust emission efficiently from mineral processing plants and opencast mines. The developed system has special features for facilitating eco-friendly mining.

By William G. Holroyd

In January 1992, the Office of the US Trade Representative announced that the People's Republic of China had agreed to protect US intellectual property, including computer software, sound recordings, agrichemicals and pharmaceuticals. Under the agreement, China will make significant improvements in its patent, copyright and trade-secret laws. Ambassador Carla A. Hills, the US trade representative, said "this agreement should create significant opportunities for US firms interested in marketing high valued-added products to China." Principal beneficiaries will include the agrichemical and computer industries, as well as pharmaceutical, entertainment. The agreement will safeguard these industries' intellectual property, stimulating new exports to China and helping to generate additional growth in the US. Refractory grade bauxite was included in the mineral category of the $1.5 billion of Chinese products on which the US government threatened to impose an immediate 100% trade tariff. Refractory bauxite is available from Guyana and Brazil at higher cost and in different grades. However, refractory brick manufacturers would have had little choice but to pass on the costs to their consumers. Although the United States and China are separated by political ideology and internal governing structures, this agreement recognizes the importance of a $19 billion trading relationship. Consequently, the renewal of China's most favored-nation trading status in the US congress in -June 1992 was all but assured. Many US companies doing business in China and Hong Kong have been quietly increasing their investments since 1989. These companies can now concentrate on developing sales to the domestic Chinese market. This market is expected to surpass 1.2 billion people in 1995 and approach 1.3 billion by the end of the century.

Jan 1, 1993

By Malcolm D. Flavel

As indicated in the introduction to this paper, it is a sequel to that which I gave to the last annual meeting in Atlanta in march. This paper goes further into aspects of crushing and screening, primarily from the standpoint of circuit control. There has been little published by equipment manufacturers on this subject and this is the first paper on crushing circuit control to be sponsored by Allis-Chalmers corporation. By proper control over the use of crushing energy, we will be able to produce finished products from feed materials uti¬lizing minimum capital for the lowest cost of production. The subject will be discussed as follows. Firstly, we will look briefly at what we are trying to accomplish; Secondly, what is presently available in the way of technology; Thirdly, we will look at a suggested new system of control which will best fit the parameters of the normal crushing and screening operation; As a conclusion, I will summarize the advantages of the new system.

Jan 1, 1977

By C. Sun

The Leeville underground mine has been in operation since 2006 and currently produces 2,903 t (3,200 st) of ore per day, with an average gold grade of 0.4 opt. The mine’s horizontal extent is large, 762 by 152 m (2,500 by 500 ft), while its vertical extent is 6 to 61 m (20 to 200 ft). A high density of joints occurs within the host rock. Based on rock mass rating and field observation, the ground conditions at Leeville can be characterized as poor to very poor. As such, heavy ground support is required for its mining operation. Ore zones with a height in excess of 10 m (35 ft) are considered for longhole stoping. A typical stope measures 6 m (20 ft) wide, 30 to 55 m (100 to 180 ft) long, depending on the ground conditions, and 10 to 30 m (35 to 100 ft) high, depending the thickness of the ore body, yielding 9,100 to 18,000 t (10,000 to 20,000 st) when completed. Narrow ore zones, less than 10 m (35 ft), are mined using cut and fill. Drifts at the Leeville Mine are 4.6 m (15 ft) wide by 4.6 m (15 ft) high. Because of poor ground conditions at this mine, the establishment of a ground control monitoring system is key to operating both safely and successfully. This monitoring system is composed of comprehensive instrument design and installation. Instruments include multi-point borehole extensometers (MPBX) and “stretch measurement to assess reinforcement tension” (SMART) cables. The monitoring system covers the mining zones and infrastructure openings. After about two years’ application and measurement, useful data has been collected and continues to be collected; this information will be used to design future stopes and infrastructure. The system makes engineering and operation teams able to do their job with more confidence and efficiency.

Jan 1, 2009

By Roger D. Sharpe

Oklahoma contains extensive resources of high-purity gypsum that were deposited in the Anadarko and Hollis basins during Permian time. The gypsum resources and reserves are estimated to be about 48 billion short tons and a; located in the western portion of the state. Oklahoma is the largest producer of gypsum products in the United States. The Blaine Formation and the Cloud Chief Gypsum contain several beds of minable thickness. Four stratigraphic units in the Blaine Formation are quarried in Oklahoma. The Shimer, Nescatunga, and Medicine Lodge Members are quarried in northwest Oklahoma. The Van Vacter Member, consisting of three gypsum beds, is quarried in southwest Oklahoma. The Cloud Chief Gypsum is quarried in the west-central part of the state. The gently dipping gypsum in the Blaine Formation generally crops out along low escarpments and is covered in the downdip direction by increasing overburden, consisting of sand, shale, and/or dolomite. Anhydrite occurs in the downdip direction under the thicker overburden. The Cloud Chief Gypsum crops out as hills, which are eroded remnants of a more widespread, massive sulfate unit. All of the gypsum produced in Oklahoma is extracted using quarrying methods. A variety of products are made from gypsum quarried in Oklahoma. The products are manufactured from uncalcined, calcined, and deadburned gypsum. Products vary from raw, ground gypsum used for agriculture, to high-value-added industrial plasters, cements, and fillers produced from calcined gypsum. A sampling of the many products manufactured from Oklahoma gypsumincludes: (1) agricultural-soil amendment; carrier for insecticides, pesticides, and herbicides; calcium supplement in animal feeds; (2) gypsum wallboard-common, fire-resistant, and water-resistant varieties; (3) industrialgypsum plasters-art and casting, pottery and ceramic, molding and tooling, crayons, wall patching; (4) industrial gypsum cements-oil-well cement, high-strength statuary, high-strength tooling, fiber-reinforced architectural, road and bridge repair; (5) food and pharmaceutical-filler and binder in aspirin and other medicines, yeast activator in brewing of beer, moisture absorbent in bread and pizza dough; and (6)portland-cement retarder-ground with clinker to control setting time.

Jan 1, 1999

By David M. Spatz

Anyone who scans the modern literature will realize that concepts of leadership have changed during the past few years. And like change in so many areas of our culture, change has been rapid in the perception of leadership. Many traditional leadership traits are still highly regarded and many of the longstanding personal qualities that improve leadership abilities continue to be effective. In the past, though, leaders could rely on dominance, intimidation and fear to accomplish their goals through the actions of others. In contrast, effective leaders today build relationships, provide vision and guidance, and strive for communication, cooperation, trust and employee satisfaction. Earnest leadership involves moral issues like honesty, integrity, fairness, empathy and respect. Modern leaders guide, facilitate and coach, rather than command and direct. But how well equipped are managers in the mining industry to meet the leadership challenges that lie ahead? More importantly, is he or she becoming a better leader? This article outlines steps to becoming a more effective leader. Management consultants stress that the changes that lie ahead will demand swift organizational adjustments and managers who are equipped to lead during times of change (Boyett and Conn, 1991; Hesselbein et al., 1996; White et al., 1996 and Kotter, 1997). Becoming a better leader begins with self-assessment and a commitment to unify all who depend on one's leadership abilities. Simply defined, leadership is leading others. Contrary to common practice, leadership is not about advancing one's own career but about bringing out the best in others. The beauty of modern leadership, however, is that the path of serving others creates synergies. They benefit everyone, including the leader, those the leader manages, upper management and company shareholders.

Jan 1, 1998

By G. Deschenes, M. Fulton

The New Britannia Mine processes a qumtz-carbonate gold ore containing 4.63 git Au at a rate of 2,200 tpd. The ore contains approximately 3 .0% arsenopyrite, 2. 7% pyrite and the rest is gangue minerals. Eight to ten percent of the gold is refractory to leaching. Two years ago, New Britannia Mine experienced cyanidation problems. Gold extraction was not stable and occasionally decreased significantly. Preliminary test work, at laboratory scale and in the plant, indicated that lead nitrate addition was beneficial. A laboratory study was initiated to evaluate the level of control of the parmneters (grinding size, dissolved oxygen, pH, free cyanide and lead nitrate) to optimize the efficiency of the process. It was found that lead nitrate addition is required to alleviate the effect of metallic sulphides. This addition causes a significant increase in the gold leaching kinetics and a reduction in the cyanide consumption. The optimum system appeared to be: leaching for 24-30 hours at pH 11.8, 50 git lead nitrate, 250 ppm NaCN and 8 ppm 02. The gold extraction was 89.8% with grinding at 89%-74Fm (leached tail at 0.48 git). Cyanide and lime consumption are 0.40 kglt NaCN and 1.9 kglt respectively. Following the incorporation of lead nitrate, overall gold extraction was increased from 89.2% to 91.1 % but no change was noticed in cyanide consumption. The gross profit is $CDN 988,000 per year.

Jan 1, 1999

By Frank W. Bowdish

Studies of sulfidization and flotation of chrysocolla involving the use of pH and sulfide ion instruments, a Zeta meter, microflotation techniques, and sensitive determinations of adsorbed sulfur have given new insight into the mechanism of the process. Factors that affect the recovery of sulfidized chrysocolla by flotation appear to be the pH at which it is sulfidized, and certain alterations of the surface that occur during aging after sulfidization. Such aging results in increased recoveries. The surface charge, as measured by electrophoretic mobility, of chrysocolla shows an unexpected negative increase as pH values are changed from 6.0 to about 4.5, and this appears to be correlated with increasing sulfur adsorption and flotation recovery over the same or even wider pH ranges.

Jan 1, 1970

By N-h. Mao

We applied kriging (geostatistics) to interpret the structure of basement rock in Yucca Flat, NTS from borehole data. The estimation error for 118 data is 81 m comparable with those based on both gravity and borehole data. Using digitized topographic data, we tested the kriging results and found that the model validation process (Thomas option) on data gave a fair representation of the overall uncertainty of the kriged values.

Jan 1, 1985

By Miguel Reyes, Chenming Zhou, MATTHEW GIRMAN

Electromagnetic energy emitted from electronic devices has been known to interfere with other electronic systems, hindering their ability to function properly. Mines have many electronic devices critical to the health and safety of mine workers that could be negatively affected by electromagnetic interference (EMI). To ensure that devices are electromagnetically compatible, tests must first be conducted to measure emissions and check for immunity. There are many standards available across multiple industries that prescribe emission limits and test methods for electronic devices. Due to the unique environment of an underground mine, it may not be enough to simply adopt a standard from another industry to mining. A literature review has been conducted, and an overview of EMI standards in other industries will be provided in this paper. Also, an example of how a standard can be applied to mining equipment is presented. Finally, recommendations on standards which could potentially be applied to mining will also be included. This work will inform the mining industry of EMI standards in other industries so that mine workers and technology manufacturers have guidance of the steps that can be taken to investigate and reduce the impact of electromagnetic interference and potentially work toward electromagnetic compatibility. The findings and research involved in this effort can also be used to explore the need to develop mining-specific EMI recommendations and standards.

Nov 25, 2021

By Robert Giglio

Looking back over the last 150 years or so, it is not hard to see that electricity has been a primary force in shaping human development. It has been a basic ingredient in our industrial revolutions that simultaneously improved the productivity, working and living conditions within our farms, factories, hospitals, offices and homes. Today, it has become an essential part of our daily life and our future. Amazingly, we keep finding new ways to use electricity to make our lives more safe, comfortable and productive. It is a great success story of human ingenuity, achievement and development. Demand for electricity The convenience and value of electricity has not gone unnoticed by consumers. According to the U.S. Department of Energy (DOE) (Energy Information Administration, 2009), electricity is the fastest growing form of energy in the world and during the next 20 years the world will likely consume twice as much of it as it does today. In 2008, almost 20,000 terawatt hours of electricity globally were consumed (Energy Information Administration, 2009). That is enough electricity to light up more than two million baseball stadiums or power more than 11 billion computers continuously for an entire year. The United States has the dubious distinction of be-ing the largest consumer of electricity in the world with enough power to provide each American with more than 3 kW of electricity ? that is about twice the power currently available to Europeans, eight times the power available to the Chinese and more than 25 times the power available to the citizens of India (American Coal Foundation, 2009).

Jan 1, 2009

By J. Dorsey

In 1910, Colonel Boyce Thompson, who owned Inspiration (now Cyprus Miami) and various other mining interests, formed the Magma Copper Company and leased the Silver Queen claims around Superior, Arizona. At the same time, he purchased other claims around the Silver Queen claims from what was then called the Magma Mine. The mine continued to operate until 1982 when Newmont Mining Company, who owned Magma Copper Company, shut down the operations due to high costs and low copper prices. When Magma was spun off by Newmont as an independent company in 1987, new studies of Superior were started. It was clear from these studies that the mine had been shutdown and over 1400 employees laid off for two basic reasons: first, as a resu1t of a mine plan that was technically flawed and second, be-cause of very high production costs mainly due to the low productivity from a very high cost work force. During 1989 a plan was formulated to re-open Superior with the determination to over-come the problems that resulted in closure. A new mine plan was developed and a management style developed that promotes team work and high productivity.

Jan 1, 1992

By Diler Katircioglu-Bayel

This study aims to investigate the effect of combined mechanical and ultrasonic milling on the size reduction of talc. First, the talc sample was wet-ground in a stirred media mill for five different lengths of time (30, 60, 90, 120 and 150 min), and the optimum result was subsequently achieved with treatment by ultrasonication. The effects of amplitude (20, 35 and 50 µm), solid ratio (2.5, 5, 7.5 and 10 percent), and sonication time (60, 120 and 240 min) on the sizes of the final product were investigated. The pre-milling by wet grinding caused a decrease in the grinding resistance of talc. Sequential ultrasonic treatment, which was applied to the talc sample, generated smaller particles in comparison to those acquired by stirred media milling alone. Experimental results were assessed based on the product particle size (d10, d50 ), reduction ratio and specific energy consumption. Submicron particles prepared by ultrasonic treatment were highly stable compared to stirred media milling alone as investigated in terms of particle size. In addition, the effects of mechanical and ultrasonic milling on the structural properties of talc particles were characterized by X-ray diffraction (XRD) analysis.

By N. S. Tanious

Three water-spray ventilation systems were tested to determine their effectiveness in diluting methane at a room and pillar coal mine face. These systems were: the shrouded nozzle, the spray fan, and the conventional nozzle system that is normally supplied with continuous miners. The testing was carried out in two stages. The air-moving capacities of the nozzles were first evaluated in a duct. The duct tests showed that: (1) the volume of air moved by the nozzle is controlled by the type of nozzle, the space around it, and its location relative to the duct wall; (2) the spray fan nozzles or the shrouded nozzles are both capable of moving air quantities up to 6400 cfm (3.02 m3/s); and (3) when the shroud was removed from around the shrouded nozzle, its bare nozzle moved between 9 and 65 percent more air. In the second stage of testing, a full-scale evaluation of the three systems was conducted. The three spray systems were mounted on a continuous miner which was positioned in an aboveground simulated mine entry. The simulated face tests gave the following results: (1) the standard nozzle system, which is mounted on the front end of the miner, is inadequate for diluting methane; (2) under the best testing conditions (lowest methane emission rate, highest primary ventilation airflow, and closest brattice set back), the slight improvement given by either the shrouded system or the spray fan is the same; and (3) under the worst testing conditions (highest methane emission rate, least primary ventilation airflow, and farthest brattice set back), the spray fan gave superior performance.

Jan 1, 1987

By A. Patrick Ryan

To many people, the word cartel implies illegality. However, although it is illegal in the US, cartels are an effective and legal way to conduct business elsewhere in the world. But be-fore we continue, what is a cartel? The American Heritage Dictionary defines a cartel as "a combination of independent business organizations formed to regulate production, pricing, and marketing of goods by the members." However, that definition does not fit many of the "cartels" we are examining today. The International Tin Council is an organization of both consumer and producer nations--no individual companies are represented. The buffer stock is used by the ITC to provide protection for both producers and consumers, and has only been in effect since 1955. (Earlier tin producers groups date back to 1921 when the Federated Malaysia States and the Netherlands East Indies formed the first intergovernmental tin agreement, known as the Bandoeng Pool, which only lasted three years.) The International Bauxite Association only dates back to 1974 when seven nations--Australia, the Dominican Republic, Ghana, Guinea, Guyana, Haiti and Jamaica--agreed to three main objectives: 1) to promote the orderly and rational development of the bauxite industry; 2) to secure a fair and reasonable return on the raw material for the benefit of the nations' citizens; and 3) to safeguard the interests of member countries in relation to the international bauxite industry. 1 Again this organization is composed of nations, not separate firms. This generally follows the pattern that the oil producing countries (OPEC) chose since the nations' mineral product-ion is controlled and often owned by the state. However, the group I am going to discuss fits the more classic mode of a cartel. The informal lead-zinc producers' cartel can be dated as far back as to Roman times when Romans are said to have imposed a quota system on British lead production to safeguard their Spanish lead mines. Also, the lead-zinc producers group is composed only of individual companies, not do not include any lead-zinc consumers. Finally, the activities of the group are not open to public scrutiny, and details are only now available due to a leak in the Australian government. At this point, it is necessary to split the two metals since while many of the members of the cartels produce both lead and zinc they do have different histories and marketing arrangements.

Jan 1, 1978

The National Mining Hall of Fame and Museum (NMHF&M) will celebrate its 25th anniversary on Sept. 22, 2012 when the 2012 class is inducted during a special ceremony in Las Vegas, NV in conjunction with MINExpo 2012. The NMHF&M will induct four men representing the equipment manufacturing, minerals exploration, copper and coal sectors of the mining industry. The diverse cross-section of mining industry giants joining the hall of fame include Glen A. Barton, J. David Lowell, Samuel Newhouse and John Cleveland Osgood. They will join 214 other mining industry pioneers when they are formally inducted into the National Mining Hall of Fame at the 25th Silver Anniversary Induction Banquet & Ceremony. These men were selected for being visionaries, leaders and ambassadors within their own sectors and across the industry at large.

Jan 1, 2013