Search Documents

By Brad Hewitt

Since Campbell Mine began processing ore, there has been a gravity gold recovery circuit. From 1947 to 1982, gravity gold was concentrated through the combination of jigs and mercury amalgamation. In 1982, jigs with concentrating table upgrading commenced and was utilized until the end of 1994. As of January of 1995 to the present, Knelson Concentrators in com­bination with concentrating tables have been employed to achieve a refinable product. An evaluation of the justification used for the last change is the focus of this paper.

Jan 1, 1996

By Bernie W. Martin

The East Side Access (ESA) project is the largest commuter railroad project ever undertaken in the United States. The purpose of the ESA project is to bring commuters from Long Island into Grand Central Terminal. The program is estimated to cost $4.3billion. The purpose of this paper is to describe the key design elements for the Queens segment, ?re life safety, ventilation and changes to the proposed contract delivery method.

Jan 1, 2003

By Gareth Mainwaring

The Cross Harbor Freight Movement Project is currently in the Environmental Impact Statement phase. The scheme is addressing alternative solutions to transport freight across the Upper Bay of New York Harbor, from New Jersey through to Brooklyn, Queens and Long Island. Amongst the alternatives being assessed are two tunnel options; from the north shore of Staten Island through to Brooklyn, and from Jersey City to Brooklyn. These tunnels are approximately 30,000 feet in length, and with up to17,000 feet under the Harbor, would make it one of the longest undersea crossings in the world.. The paper addresses the development of the project, from the Major Investment Study through to the current EIS, and describes the tunnel schemes that are being taken forward. The geological conditions that will be encountered, proposed construction methods, and the ventilation issues associated with such major undersea tunnels will all be described.

Jan 1, 2003

By Otis M. Clarke

The Eufaula bauxite-kaolin district in southeastern Alabama is an important source of raw material for the refractory industries in the United States. At the present time, five companies are mining and processing bauxite and kaolin from this district and a sixth company is holding substantial reserves. Mining operations are expanding, but finding new ore reserves is a major problem. The Geological Survey of Alabama sponsored geologic research in the Eufaula district to: 1) investigate the utilization of sandy kaolinS and other clays associated with bauxite-kaolin deposits; 2) find limits of the bauxite district, looking for possible extensions; and 3) study the geology of the district, looking for patterns or trends that may aid in finding new ore reserves. This work was done with the full cooperation of mining companies operating in the district and property owners. Research was aided by the U.S. Bureau of Mines and the University of Alabama. The investigation included detailed geologic mapping of mines, drilling in selected areas, and making mineral analyses of bauxite and clays. The mapping was performed primarily by pace and compass because of the complexity of the deposits studied, but aerial photographs were used to a limited extent. Drilling included both auger and core drilling. The auger drilling was limited to 100 feet, but core holes were drilled as deep as 200 feet. The term 'bauxite,' as used here, indicates a mixture of minerals containing more than 50 percent gibbsite. Bauxitic clay is a mixture of gibbsite and kaolinite that contains more kaolinite than gibbsite. The term "kaolin" indicates a clay composed of predominantly kaolinite. Other clays in the Eufaula district are composed of kaolinite, illite, quartz, mica, and goethite or hematite.

Jan 1, 1971

By Jack A. James

Lancaster Lime and Stone Corporation developed a quarry operation in 1971 and 1972 for the production of high calcium limestone and construction aggregates, or roadstone. The quarry operation is situated in southeastern Pennsylvania in the northern part of Lancaster County. The geology of the high calcium limestone deposit had a powerful influence on all aspects of planning this operation. My purpose is to trace the influence of geology throughout the planning and thereby point out the discipline that geology imposed on the planning, and indeed, continues to impose on the operation. Lancaster Lime and Stone Corporation is one of four wholly- owned subsidiary companies of Kurtz Materials Corporation. Kurtz Materials Corporation, through its operating subsidiaries, is a supplier of basic materials to the construction industry including crushed stone, ready mixed concrete, concrete masonry units and a wide range of precast and prestressed concrete products.

Jan 1, 1973

By George S. Austin

Adobe, dried mud bricks, have been used since before historic time in the construction of dwellings. Building materials are normally evaluated for thermal performance based on measurements known as R- and U-values. The R-value is an indicator of the ability of a wall to insulate effectively and the higher the R-value, the better it is as an insulating material. The U-value, or value of conductance, is the reciprocal of the R-value and reflects the rate at which heat is conducted through a material. But the "heat capacity of the wall" must also be considered. This measures the length of time that passes before a steady state of heat flow is achieved. The effective U-value measures both the resistance to the transfer of heat and the capacity to hold heat. These latter value make adobe a far more interesting as a modern building material that was formerly recognized.

Jan 1, 1983

By Eileen Ashworth

Computer-assisted instruct ion is now being used in areas as diversified as training handicapped children to preflight simulation for airline pilots. This paper reports on two courses that have been developed at SDSM&T on the PLATO system for miner safety training. Advantages of computer-assisted instruct ion for this type of training is discussed. (Figures show examples of actual use.) A discussion will be given on other applications such as maintenance troubleshooting, training of engineers and managers at remote sites and training of local people for working in the mine.

Jan 1, 1983

By C. B. Manula

The application of computers to materials handling problems has recently been investigated by various mining groups. This approach has been found, especially useful where a large amount of alternatives must be investigated prior to arriving at a final decision. These alternatives may be expressed in terms of man hours, units and types of equipment such as trucks or conveyors, or the allocation and operation of proposed or existing haulage facilities. The decision problem becomes especially evident when we consider the mechanical revolution which has flooded the mining industry in recent years. The industry has become highly competitive, with the need to keep low profit materials away from high cost production faces ever increasing. The capital investment required for the highly sophisticated equipment that is necessary to perform this function is generally great, and management is faced with decisions which must all too often be made without sufficient data.

Jan 1, 1967

By J. W. Rinard

This paper is intended to introduce "non engineers" to one of the more misunderstood pump performance parameters, NPSH (Net Positive Suction Head). This basic presentation and resultant review should provide a practical understanding of NPSH and what its importance is to pump operation and reliability.

Jan 1, 1996

By Grover Wallace

At is important for today?s mining executives and leaders not to underestimate the fact that, while the recent downturn in the economy did take its toll on balance sheets and productivity, factors such as emerging countries, aging workforces, globalization and individual knowledge growth did not lay dormant while the economy was in a lull. It is key for mining leaders to be proactive in their talent strategies. Successful mining companies are developing a clear, concise and communicated strategy and placing a high priority on recruiting the right talent in global markets that parallels their business strategy. They are focused on placing the right people in the right jobs.

Jan 1, 2011

By R. E. Miller

Hoisting coal using water and air is a technology which has potential to improve the economics and safety of transporting coal. The Coal Air-Lift Hydrohoist is a prototype coal hoisting system developed by the U.S. Bureau of Mines (USBM). This paper discusses the method used to regulate the supply of water to the 50-m-high hydrohoist U-tube such that the pressure difference at the bottom of the U-tube is held constant. Maintaining a constant pressure difference results in a steady flow of slurry out of the hydrohoist.

Jan 1, 1995

By Nancy J. Wheatley

I. INTRODUCTION The Massachusetts Water Resources Authority (MWRA) is a regional water and sewerage authority which provides wholesale water and sewer services to the Metropolitan Boston area. The MWRA was created by the Massachusetts Legislature as an independent authority in 1985 following the filing of a lawsuit in federal court to correct the pollution of Boston Harbor resulting from inadequate and inadequately maintained sewerage facilities. Immediately upon its creation, the MWRA began to tackle treatment plant issues, including addressing the need for a secondary treatment plant, planning for ceasing ocean discharging of sludge, and making interim repairs to the existing, antiquated treatment plants. The MWRA's initial activities led to a court-ordered schedule for construction of a single new primary and secondary treatment facility, for development of sludge management plan focussed principally on reuse, and for completion of a short term program of repairs to existing facilities. Once a schedule for completing these activities had been negotiated, the U.S. Environmental Protection Agency (EPA), a plaintiff in the federal court case, asked that the MWRA take "responsibility" for controlling discharges from combined sewer overflows (CSOs) within its service area. Combined sewers (sewers in which both sanitary sewage and storm water runoff are carried in a single pipe) presently discharge over 10 billion gallons of untreated wastewater into Boston Harbor and its [ ]

Jan 1, 1991

By C. E. McFarland, N. W. Kirshenbaum

Cortez Gold Mines is located about 75 miles southwest of Elko, NV. Activity in the mining district dates from 1862. The current operation developed from a 1963 joint venture of Webb Resources, The Bunker Hill Company, Vernon F. Taylor, Jr., and American Exploration & Mining Co. Three years later, the USGS discovered gold on the property following a regional geochemical survey. Drilling in 1966 and 1967 identified 3.4 million st of oxide ore grading 0.28 oz Au/st, and a 1700 st/day countercurrent decantation mill was commissioned in 1969. Heap leaching started in 1971 on low grade ore and continues to the present. The mill was shut down in 1976 following exhaustion of known oxide reserves. Mobile equipment was sold and the proceeds committed to local exploration. In 1980, a new plan of operations was developed starting with existing low grade and newly discovered mill ore. The mill resumed operations in 1981 and has been operating to date. A series of metallurgical innovations, culminating in the commissioning of a new fluid bed roaster in the summer of 1990, has enabled treatment of a series of increasingly refractory ores. Current partners in the venture are Kennecott Corporation, Vernon F. Taylor, Jr., and Placer Dome U.S. Inc., manager of the operation. Idaho Mining Corp. holds a 7.5% carried interest.

Jan 1, 1992

By A. B. Seal, C. J. Bise

Excessive noise has long been a hazard in the coal-mining industry. Studies conducted during the mid-1970s and mid-1990s consistently show that hearing loss within the mining industry persists, in spite of regulatory requirements and sampling technology advances. When the U.S. Mine Safety and Health Administration's new health standards to protect miners from hearing loss took effect in September 2000, the potential developed to reevaluate sampling approaches with regard to noise-source hazards, such as task-based methods. This paper describes results from a Pennsylvania State University research project now being conducted at an underground coal mine. Each occupation was reviewed, and a list of tasks or processes performed by each was generated. Traditional personal noise dosimetry, static sound pressure levels and equipment sound mappings have been performed. Job tasks indicating the greatest levels of daily noise exposure and contributions to noise dose have been identified and will be discussed.

Jan 1, 2003

By A. D. Agate

In developing nations, novel mineral processing methods like bacterial leaching are gaining prominence. The principles and practices for isolation and preservation of cultures used in bacterial leaching are discussed with special reference to cultures used in leaching copper from Indian ores. In all, 145 potentially useful microorganisms such as iron- and sulfur-oxidizing bacteria were isolated from various ecosystems of the copper mining areas in the country. The major organisms isolated by enrichment culture technique belonged to T. ferrooxidans and T. thiooxidans species. In addition, thermophilic cultures like Sulfolobus sp. and thermophilic thiobacilli were also isolated. The process of copper leaching was scaled up to the 300-kg level in PVC columns. Since the preservation of efficient cultures in active state was vitally important, a new method was devised that preserved the activity of thiobacilli for a period of more than two years. The novel method of storage in sterile chalcopyrite ore at 8°C can be considered an important advance.

Jan 1, 1987

By V. Rajaram

The Metropolitan Water Reclamation District of Greater Chicago (MWRD) imposed a no-blasting specification (blasting is restricted to the construction shaft and shaft bottom or boot) on the Deep Tunnel project in 1988. This was prompted by numerous complaints from the residents in the vicinity of the project, and controversies experienced on previous projects from blasting the rock overlying the tunnel. This paper will describe the methods utilized by two major contractors who are driving 20 km (12.5 of tunnel along with drilling over 36 shafts under this restrictive specification. The impacts on design, construction, schedule, cost, and the environment are detailed.

Jan 1, 1991

By D. Murray

"The Mine Improvement and New Emergency Response (MINER) Act included the need for improved chemical technologies to address respiratory protective device inadequacies and refuge alternative development. The National Institute for Occupational Safety and Health’s (NIOSH) National Personal Protective Technology Laboratory (NPPTL) invests in research and development to improve the carbon dioxide (CO2) scrubbing technologies built into these mine safety systems. Testing at NIOSH NPPTL is performed using a custom-designed test system containing a chemical reactor and sensors in a constant flow of simulated expired breath to evaluate chemical performance for the scrubber materials. Current testing procedures focus on device duration or capacity, but do not report criteria needed to effectively optimize chemical performance. In this presentation, testing results which identify the chemical performance roles for CO2 scrubber components will be reported, and specific component chemical activities will be linked to both duration and CO2 absorption capacities. Chemical components being evaluated include hydroxyl, superoxides, metal, and amine active sites, distributed in salts, zeolites, metal-organic frameworks, and microporous materials. INTRODUCTION CO2 absorbents and oxygen sources are at the heart of closed circuit breathing air supply systems used in mining escape and rescue operations. CO2 absorbent technology was first developed for diving rebreathers and has been in use for over a century. Typically these devices include a soda lime formulation of pellets in the 8-12 mesh range. Larger 4-8 mesh particles are used in medical grade “low-flow” applications, since these particles present a lower flow resistance regime more amenable for use with resting individuals. Potassium superoxide and lithium hydroxide formulations are also used, where in each case the formulations involve bulk solid pellets or materials affixed to surfaces. CO2 capture technologies are now under intensive study in the energy and automotive industries, where the pursuit of optimal combustion processes has led to the development of new materials to capture, convert and store CO2, oxygen and carbon monoxide gases. Recent advances in nano-structured and high surface area catalysis have produced novel materials demonstrating chemical performance improvements in these industries, and these improvements may now also be adapted to enhance chemical efficiency and performance in escape and rescue devices. Higher surface area materials offer promise for improving the efficiency, or decreasing the burdens associated with the use of closed circuit respiratory protective devices containing CO2 absorbents. Novel chemicals that display advantages in chemical performance or decreased burden will be examined for inclusion in developing systems such as the next-generation closed-circuit mining escape respirator or refuge alternatives."

Jan 1, 2018

By S. Frimpong, E. Siami-Irdemoosa, S. R. Dindarloo

"Electric and hydraulic shovels are the dominant loading machinery in surface mining operations. Despite their critical role in production and their high capital and operating costs, no reliable and comprehensive quantitative performance metric is available. In this paper, a stochastic shovel effectiveness (SSE) measure is proposed for the purpose of quantifying the performance effectiveness of these shovels. The SSE is based on the widely used method of overall equipment effectiveness (OEE) in the manufacturing industry. The OEE measures the performance effectiveness of equipment by multiplying its mechanical availability, utilization and production quality. In manufacturing processes, quality rate is the ratio of the total number of products minus the number of defective products – equivalent to the number of acceptable products – to the total number of products. The SSE similarly uses the mechanical-availability and utilization terms, but instead of quality rate it uses a new parameter named bucket rate.The variability or randomness of the input data, that is, availability, utilization and bucket rate, are further incorporated into the SSE, and a final stochastic SSE distribution is derived in the form of a probability density function. One hydraulic and one electric shovel in a surface mining operation were selected to test the validity of the proposed method. The SSE scores for the two shovels, operating continuously for one year, were derived and compared. As with the OEE, the three-parameter SSE method yielded more representative results for overall performance measurement than a single-parameter approach. Using Monte Carlo simulation, a three-parameter Weibull and a normal distribution were derived for quantifying the overall effectiveness of hydraulic and electric shovels, respectively. As a decision aid, the proposed methodology promises to render a more informative tool than traditional metrics for mine equipment maintenance and management."

Jan 1, 2015

By S. J. Porter, M. T. McRae

The new tunnel at Genting Sempah is part of a privately funded infrastructure projectthat involves duplicating the existing highway extending from the Gombok Toll Plaza near Kuala Lumpur to Karak, in Malaysia. The 60 km long tollway includes an 800 m long, two-lane highway tunnel with excavated dimensions of 10.5 m wide by 8 m high. The majority of the tunnel extends through slightly to moderately weathered, moderately to highly jointed quartz porphyry. Excavation of the tunnel was performed using drill and blast methods and the primary tunnel support consists of rock dowels and shotcrete except for short sections adjacent to the portals where steel sets were utilized. A portion of the tunnel encountered sheared and altered material that was successfully supported using rock dowels and shotcrete. The final lining for the tunnel consists of mesh and fiber reinforced shotcrete. The flexible nature of the primary support and shotcrete final lining resulted in considerable cost savings and expedient construction methods.

Jan 1, 1997

By K. T. Dreher, J. A. Brierley, C. L. Brierley

Water from underground uranium mines located in the Ambrosia Lake district near Grants, New Mexico, U.S.A., is treated to reduce levels of uranium, selenium, radium and molybdenum. The treatment system consists of a series of ponds and an ion exchange plant. Bacterial and algal populations present in the pond system are considered agents which actively assist in removal of the pollutants present in the water. Pondbottom sediments maintain a reducing zone and a large population of sulfate-reducing bacteria of the genera [Desulfovibrio] and [Desulfotomaculum]. Uranium, molybdenum, and selenium accumulate in the pond sediment. Stimulation of the microbial sulfate-reducing activity resulted in a decrease of soluble concentrations of these elements in laboratory systems. Predominant components of the treatment ponds’ algal flora are the filamentous [Spirogyra] and benthic [Chara]. Laboratory study indicates that [Spirogyra] is more active than [Chara] in removal of uranium and molybdenum from solution. However field-collected algal samples of both of the genera contain uranium and molybdenum. Laboratory studies indicate that death and decay of the algae in association with pond sediment does not result in return of cellbound uranium and molybdenum to the water. The algae appear to act as bio-filters for accumulation of particulate pollutants and agents for adsorption and/or absorption of soluble pollutants.

Jan 1, 1980