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By Wayne Trudel, Lloyd McEvers, Lori Clarke, Eric Saderholm, Charles Lynn Bolin, Leroy Schutz

Newmont mine geologists in Nevada are most proficient when applying technical expertise with multi-departmental teams in three main settings. The first is value creation through near-mine discovery, development and reserve conversion. Since 1986, geologists have created substantial net asset value in developing more than 1.35 kt (43 million oz) into quality Nevada surface and underground gold reserves. The second setting is value realization by supporting mine operations with ore control, selective mining, reconciliation investigations and strategic planning. The investment of technical research on reconciliation investigations led to new concepts and practices that highlighted opportunities for large revenue and reserve gains. In 2002, more than $65 million in projected revenue was added to the Gold Quarry south layback. Kriged mine polygon construction and controlled blast heave at the Lone Tree Mine provided millions of dollars in mining efficiencies. High-quality geologic advice in selective mining at the Twin Creeks Mine helped obtain $4.3 million revenue gains throughout 2002-2003.

Jan 1, 2004

By R. W. Chappell, M. W. Hills, R. L. Olsen

A stochastic approach was developed and applied to the Butte, Montana Hillside abandoned mining site for modeling stormwater runoff and subsequent receiving stream loadings. This approach enabled capture and quantification of the uncertainty associated with stormwater quality data and allowed the prediction of copper and zinc concentrations in the receiving stream caused by runoff from the Butte Hillside during storm events. Runoff flows and stormwater concentrations were input to the model as probability distribution functions. Monte Carlo simulation allowed prediction of expected instream concentrations in the form of cumulative distributions functions. The modeling results allowed evaluation of current best management practices (BMPs), targeting of future BMPs, and identification of key data gaps to fill during future sampling activities. This modeling approach is considered extendable to other active and inactive mining sites. Output from a model of this type is easily understood and can be used to communicate effective stormwater management to site regulators. Furthermore, application of this modeling approach will facilitate the development and implementation of a site-specific stormwater management plan and will optimize efforts to achieve standards for compliance with stormwater discharge permits.

Jan 1, 2002

By A. H. Shapiro

A decanter centrifuge of novel design was developed for the dewatering of fine-solids slurries having micron-range particles that form paste-like, flowable, hard-to-dewater cakes. The design combines a compound beach with a cake-flow control structure that allows expressed liquid from the cake in the dry beach region to be returned back to the liquid pool while maintaining high solids throughput. In order to provide optimal performance with various operating parameters (feed rate, centrifugal gravity, pool, differential speed, concentration of feed solids, and different slurry types), the cake-flow control is adjustable. The second part of the beach is preferably at zero angle. Tests showed that the new design allows increases in both solids dryness and solids throughput.

Jan 1, 2001

By Georgene Renner, William R. Yernberg, Steve Kral

Agapito Associates (AAI) provides consulting services in geo-engineering, mining engineering and related disciplines. Founded in 1978, the firm operates out of offices in Grand Junction, CO, Golden, CO and Lombard, IL. Members of the staff include mining, civil and geological engineers, physicists, geologists, numerical analysts, computer specialists, instrumentation specialists, plus administration and technical support personnel. AAI has provided consulting and engineering services to mining companies producing base metals, precious metals, coal, potash, trona, limestone, oil shale and salt, and to defense and nuclear-waste disposal industries. AAI also provides services for measuring in situ horizontal stresses using an advanced biaxial overcore stress downhole measurement system developed by Sigra of Australia. Since 1978, AAI has measured in situ stress in copper, oil shale, molybdenum, trona, limestone and coal mines, and in tunnels and concrete structures. Since 1994, the staff has completed 527 overcore stress determinations. AAI has the equipment and personnel for overcoring, sample coring and instrumentation installation in limited access, surface and underground mines. Portable Longyear CP-65 drills, borehole deformation gauges and strain indicators are used for difficult-access overcoring and are permissible for use in gassy mines.

Jan 1, 2006

By Lane White

The 1989 Annual Meeting and Exhibit of SME in Las Vegas, NV, February 27 - March 2, 1989, was the largest ever, drawing more than 4000 regis¬trants and 240 exhibit booths. Technical sessions included presentation of nearly 500 papers, including symposia on Biotechnology in Minerals and Metals Processing, Surplus Capacity in the International Metals Industry, and APCOM `89 - the 21st International Symposium on Application of Computers and Operations Research in the Mineral Industry. Technical sessions covered the gamut of minerals industry interests; however, the proximity of the meeting to recently surging gold development in Nevada drew special attention to gold operating practices. Several of the papers on gold processing are reviewed below. To keep pace with the strong world- wide interest in gold development, SME has scheduled three additional upcoming programs that will focus specifically on gold: World Gold '89 - Gold Forum on Technology and Practices will be held November 5 - 8, 1989 in Reno, NV, as a joint meeting and exhibit between SME and the Australasian Institute of Mining and Metallurgy. Technical sessions will encompass a full program of papers covering geology and exploration, mining, and mineral and metallurgical processing. Cooperating sponsors for this meeting include the Canadian Mineral Processors Division of CIM, The Institute of Metals, The Institution of Mining and Metallurgy, The Mining, Geological & Metallurgical Institute of India, and The South African Institute of Mining and Metallurgy. Gold '90 - Salt Lake City, UT, February 26 - March 1, 1990, will be a symposium held in conjunction with the 1990 SME Annual Meeting. Current research on the processing of refractory gold ores will generate innovative papers on process mineralogy at this symposium, with special emphasis on gold with pyrite and gold with carbon. Other sessions are planned for gold exploration and mining, gold metallurgy, gold plant design and practice, and gold in scams. Advances in Gold and Silver Processing Conference, October 1 - 3, 1990 will be held in Reno, NV. Preliminary planning calls for technical sessions on heap leaching practice, refractory ore processing, non-traditional lixiviants, bioleaching, metal recovery from solution, and the environmental aspects of processing operations. PLANT DESIGN, OPERATION Technical sessions organized by the Minerals and Metallurgical Processing Division of SME at this year's meeting in Las Vegas covered a wide range of gold operating practices. Eight papers relating to gold plant design, operation, and equipment are summarized here. Preprints of these papers are available by writing to Publications Sales, PO Box 625002, Littleton, CO 80162-5002 ($2.50 per paper for AIME members, $4 for nonmembers). Continuous elution process A. M. Stone, of Bechtel Australia Pty. Ltd., described the "Development of the Continuous Elution Process for Extraction of Gold from Carbon" (pre-print 89-75). Developed by Bechtel Pacific Corp. for Ok Tedi Mining Ltd., the Continuous Elution Process uses the same reagents as batch processes for elution of gold from carbon, while yielding significant savings in stripping vessel size and energy consumed in comparison with equivalent batch processes. The process is also simpler to operate than batch processes. Other advantages include reduced maintenance costs, higher average eluate grade, and near steady final eluate grade. Pilot testing for the Continuous Elution Process was conducted at Western Mining's Kambalda gold plant beginning in December 1982. The Continuous Elution Process is a continuous countercurrent system operating in a pressure vessel at elevated

Jan 1, 1989

By W. K. Callaway

The need to increase ore recovery and pillar stability caused the Magmont Mine staff to investigate the use of sandfill to accomplish both tasks. The use of hydraulically stowed classified mill tailings as a subsidence preventative will be discussed as well as the use of sandfill in pillar recovery and as a part of the regular mining cycle.

Jan 1, 1986

Tunnel damage from explosion and earthquake excitation is correlated with strain and particle motions. Critical strains and motions are then correlated with focal distance, which is so small that permanent strains are highly likely. The shaking process is then numerically modeled to investigate the effects of excitation frequency and joint orientation. The models confirm that near cavern blocks slide intermittently only at relatively high particle velocities during periods of low joint normal stress. Larger displacements occur with relatively small shear wave lengths or relatively high frequencies. Variation in joint orientation and rock mass dilation result in changes in displacement.

Jan 1, 1985

By Tim Q. Haldane

The ability to efficiently process lowgrade ores has allowed the Gold Fields Mesquite Mine in Imperial County, CA to expand from a 2.1 Mt/a (2.3 million stpy) rate in 1986 to its present 7.3 Mt/ a (8 million stpy) processing rate. Increased tonnage demands led to the 1989 construction and startup of a dump leach pad to supplement the existing heap leach operation. This resulted in an excellent opportunity to compare the two processes at the same operation. Additional operating costs associated with the crushed ore heaps are justified through enhanced recoveries, even at very low ore grades. Gold Fields' Mesquite Mine is a gold heap leach facility located about 55 km (35 miles) east of Brawley in southeastern California. Five open-pit mines will be developed over the projected life of the property, covering a total area extending to a maximum of 5.5 km (3.4 miles) to the east and west, and 2.4 kin (1.5 miles) to the north and south. Mesquite will process 7.3 Mt (8 million st) of ore and produce more than 6.2 t (200 000 oz) of gold in 1990.

Jan 1, 1990

By D. R. Babich, E. R. Bauer

National Institute for Occupational Safety and Health (NIOSH) researchers are conducting a cross-sectional survey of equipment noise and worker noise exposures in the mining industry. Surface and underground limestone is one commodity recently surveyed. The sound levels of mining and processing equipment were recorded to identify noise sources. Full-shift worker noise exposures were completed to determine the exposure of various occupations. This paper presents the results of the noise research conducted in both underground and surface limestone mines, detailing the equipment likely to cause worker overexposures, and the occupations experiencing overexposures. Implications for worker noise exposure reduction are also reported.

Jan 1, 2006

By A. Juganda, F. WILSON, G.E. BOGIN, H. PINHEIRO, N. SANDOVAL, J.F. BRUNE

To evaluate methane explosion hazards in underground longwall coal mines, researchers at the Colorado School of Mines developed a computational fluid dynamics (CFD) model along with a 1/40th-scale, optically accessible, physical model of a longwall mining section. In this project, CFD models assisted in the design of the physical model to ensure specifications were met to accurately represent the scaling physics as well as to assist in narrowing the experimental matrix and identifying key locations for sensor placement to measure velocity, pressure and gas concentrations. This research will help develop strategies for methane monitoring to prevent methane ignitions and explosions in longwall coal operations.

Dec 1, 2022

By T. R. Ellis

Many appraisers/valuers believe that the only valuation method available within the Cost Approach category for Real Property appraisal is the depreciated replacement cost method. Some valuation and financial reporting standards setters also believe the same. This paper introduces the minerals appraiser to a number of useful methods for mineral property appraisal that are based primarily on the principle of contribution to value, the predominant economic principle in the cost approach. Most of these cost approach methods discussed are primarily for use in valuation of exploration tracts and resource properties that have no defined reserves. However, the powerful rural cost method can be used to calculate the contribution of categories of resources, reserves, and other property components to the value of a mineral property. This method can be applied to mineral properties at all stages of development, including producing properties.

Jan 1, 2011

By M. L. Mellish

The year 1988 unexpectedly turned out to be a good year for the US coal industry. In fact, it was a third consecutive year of record coal production. Accord¬ing to preliminary Energy Information Administration data for 1988, domestic coal consumption went up 5%, or 41 Mt (45 million st), from 1987. Coal exports were up by a surprising 13.6 Mt (15 million st). In 1988, 22.7 Mt (25 million st) of coal were drawn from stockpiles for consumption. Even so, US coal production increased to 862 Mt (950 million st). That was up 28 Mt (31 million st) from 1987. While coal consumption, exports, and production were up, delivered prices for steam coal continued to slide during the year. Metallurgical coal prices, however, firmed up and showed a moderate increase. This reflected tight metallurgical coal markets at home and abroad. Coal consumption US coal consumption reached 800 Mt (882 million st), compared with 759 Mt (837 million st) in 1987. Increased metallurgical coal consumption was one factor. Most of the rise in coal consumption, however, was due to unexpectedly high electricity demand. Unseasonably hot summer weather al lowed added coal-fired electric generation to supplement the drought-related reduction in hydro-electric power supply. Electric utilities consumed 687 Mt (757 million st) of coal in 1988, 35.4 Mt (39 million st) more than in 1987. Coal-fired power plants remained the primary source of US electricity generation, providing 57% of the total in 1988. Coal consumption at coke plants increased 13%, to 38 Mt (42 million st), from the level consumed in 1987. This increase reflects the recent recovery in the iron and steel industry. Metallurgical coal consumption in 1988 could have been greater. But US coke plants reportedly reached their maximum practical production capacity. As a result, net US coke imports amounted to 1.45 Mt (1.6 million st). Despite increased industrial activities, steam coal consumption by industrial plants was up only slightly from the 1987 level, amounting to 69 Mt (76 million st) in 1988. Residential and commercial coal consumption remained virtually unchanged at 6.4 Mt (7 million st). Coal exports and imports US coal exports rebounded in 1988, reaching 86 Mt (95 million st). It was the highest level of annual US coal exports since 1982, when they reached 96 Mt (106 million st). An unusual set of factors led to an opening for US coal exporters in 1988: • a high level of industrial production in Japan and the European Economic Community, • supply disruptions due to labor problems at coal mines in Poland and Australia, • a drought-related reduction in hydro-electric power generation in Canada, requiring increased coal-fired generation, • China's problems in meeting its export commitments, and • a fall in the value of the US dollar. US metallurgical coal exports in 1988 amounted to 56 Mt (62 million st), 9.1 Mt (10 million st) more than the 1987 level. Europe, Japan, and Canada were the principal importers of US metallurgical coal in 1988. European countries, in particu¬lar, increased their take by one-third of US metallurgical coal. The labor problems in Poland and Australia contributed to these higher levels of imports. So did increases in pig iron production of 8% in Japan and 9% in the European Economic Community. US steam coal exports - including bituminous, anthracite, and lignite-increase to 30 Mt (33 million st). This was up from 25.4 Mt (28 million st) in 1987 Contributing to this overall rise were 1.8-Mt (2-million st) increase in shipments to Canada and a 2.7-Mt (3-million st) increase to Europe. Unaffected by the somewhat tighter world coal market, US coal imports showed a slight increase to 1.8 Mt (million st) in 1988. Colombia continue to be the leading exporter to the United States, followed by Canada and Venezuela. Venezuela's entry into the US market is a relatively recent one, having made its first significant shipment in the fourth quarter of 1987.

Jan 1, 1989

By Kazem Oraee

In underground coal mining, particularly room-and-pillar methods, the coal pillars play a significant role in roof stability. If the pillar dimensions are increased, the pillar bearing capacity also increases, but more coal remains in the pillar and therefore the recovery of mining operation decreases. Therefore, determining the optimum pillar dimension based on technical, economical and performance parameters is important. In this paper, the coal pillar is designed by using the concept of ground reaction curve (GRC). For this purpose, the GRC for coal pillars is drawn and then the elastic and plastic zone of coal pillar behavior is determined. Based on elastic and plastic zone, different equations are presented to draw a pillar reaction curve and the process of coal pillar design based on GRC is explained. As a case study, this new technique is applied to study the coal pillar state in Tabas coal mine of Iran. The results show that the presented new approach is successfully used in the design of the optimum coal pillar dimensions, and also determines the elastic and plastic behavior limit, which is important especially for the logical design of yield pillars.

Jan 1, 2009

By D. S. Saxena, Jack K. Tuttle

Lack of understanding of useful applications of explosives on construction work stem primarily from the fact that explosion is commonly associated with destruction. On rock excavation and other construction works a certain quantity of explosive is harnessed to perform useful work at the source e.g. blasts to disintegrate rock. Development in rock blasting techniques, including the use of multiple-row blasting with short delay ignition, have made it impossible to excavate rocks close to or below buildings even in closely built-up areas. To permit the use of explosives on construction projects, in ways that will not damage existing structures, guidelines have been developed from careful measurements of intensity of ground vibrations. Accurate electronic instruments are now available for doing this. PLANNING AND CONTROL Blasting operations must be carefully planned and carried out to avoid discomfort to persons or damage to property. This increase in the use of rock blasting in city areas alone has led to a number of problems due to ground vibrations, air shock waves, and the psychological effect of noise. While the latter seldom if ever causes damage, it does create irritation and discomfort to persons living or working near the blasting sites. A result of this is a steady increase in the number of complaints in respect of damage to houses and other premises. Many such complaints are genuine and damage may undoubtedly be caused when incorrect blasting techniques are used.

Jan 1, 1997

By Manuel Arnáiz, Pedro R. Sola, Rogelio Baudot, Manuel Herrera, Carlos S. Oteo

The aim of this paper is to describe and analyze the ground treatment performed between January and May 2002 in order to increase safety during excavation and reduce instability problems along 180 m of tunnel, during the construction works associated with line 10 extension to the Madrid Metro. The tunnel was excavated using the traditional Madrid Method and in the section considered in this paper layers of sand were detected around the tunnel crown area with a significant presence of water, the in?ow of which needed to be controlled with a minimum impact on the surrounding environment.

Jan 1, 2003

By S. Vivek

An atomic force microscope (AFM) was used to measure the surface forces between silica surfaces immersed in solutions of hydrolysable cations and/or sodium oleate. Hydrophobic forces were observed at the pH range where the concentration of the singly-charged hydroxo-complexes (CaOH+ or MgOH+) in solution is the highest. In the absence of oleate, the adsorption of the hydroxo-complexes was indicated by the disappearance of the repulsive hydration force. These results suggest that the hydrolysable cations adsorb on silica as singly-charged hydroxo-complexes. Based on the results obtained in the present work, a model for the adsorption of hydrolysable cations has been developed.

Jan 1, 2009

By Andrea Brickey, JUDITH BUABA, RICHARD AMOAKO

The global mining industry has recorded significant declines in accident and injury rates attributed to the advancement in technology, increased enforcement, and safety consciousness. A goal of the mining industry is to achieve zero injury and occupational illness on all mine sites, prompting increased research into ways to further reduce mine accidents. A machine learning technique known as multiclass logistic regression is applied on a 10-year injury dataset from the Mine Safety and Health Administration (MSHA) to determine a miner’s susceptibility to a class of injury and to help identify significant risk factors associated with different classes of injury. The data is aggregated based on injury classification to provide statistically relevant results. The analysis identifies specific risk factors that influence a mine worker’s susceptibility to a given class of injury, i.e., non-fatal with no days lost or restricted activity, non-fatal with days lost and/or days of restricted work activity, and fatal and total permanent or partial permanent disability. These factors include miner’s age, mine type (coal vs. non-coal), experience on the current job (years), shift start time, employment type (operator vs. contractor), mining district, and type of accident. The results of the analysis indicate that a miner’s experience on the job, i.e., the number of years worked in a current job, is a significant risk to injury occurrence, even for those with decades of total mining experience. We further show the differences and similarities between the surface and underground mine incidents.

Nov 3, 2020

By R. J. Sweigard, C. T. Justice, T. Beckham, E. D. Thompson, T. C. Hopkins

Fine coal refuse is often pumped, as slurry, into surface impoundments as a means of permanent disposal. As the available volume is filled, the height of the embankments are frequently increased. Many times the additional embankment material is placed upon consolidated fine coal refuse. There has been some concern about the long-term effect of consolidation of this material at or above the liquid limit upon its shear strength. A laboratory investigation was performed using three different types of fine coal sluny taken from Central Appalachian coal preparation plants. The refuse was consolidated in 10-foot plexiglass columns under incremental amounts of surcharge loading. The incremental loads were designed to simulate the effect of increasing the height of a refuse embankment on top of the consolidating coal slurry. After the refuse in the columns had consolidated for several months, the columns were cut apart and triaxial tests were performed on both the consolidated material and unconsolidated material for comparison of their shear strength parameters.

Feb 24, 1997

By S. M. Carpenter

In response to the FY2008 Consolidated Appropriations Act (H.R. 2764; Public Law 110?161), the United States Environmental Protection Agency (USEPA) issued the final Mandatory Reporting of Greenhouse Gases Rule (MRR). The rule, signed by the USEPA Administrator, Lisa Jackson, on September 22, 2009, requires reporting of greenhouse gas (GHG) emissions from large sources and suppliers in the United States, and is intended to collect accurate and timely emissions data to inform future policy decisions. The MRR will go into effect on January 1, 2010, and a report of the total emissions for calendar year 2010 will be due to the USEPA by March 31, 2011. Under the final MRR, suppliers of fossil fuels or industrial greenhouse gases, manufacturers of vehicles and engines, and certain facilities that emit 25,000 metric tons or more per year of GHG emissions are required to submit annual reports to the USEPA. The gases covered by the rule are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFC), perfluorocarbons (PFC), sulfur hexafluoride (SF6), and other fluorinated gases as outlined in Table A-1 of Subpart A of the MRR, which is also provided in Appendix A of this report.

Jan 1, 2011

By Cherie H. Tilley

The possibility of drilling oil wells from underground locations is not a new concept. It bas not been cost effective for the oil industry in the past and therefore disregarded. Today's state of the art in tunneling and shaft sinking greatly improves the potential for this type of oil field development scheme. This report presents a plan for providing a aeries of drilling bases and the design of the drilling location. The design minimizes the amount of excavation needed to develop the oil field and maximizes the use of rapid excavation techniques.

Jan 1, 1983