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By Charles L. Kimbell

Although virtually every available indicator of world mineral industry activity demonstrated a gain in 1983 relative to the 2 very poor years of 1981 and 1982, the overall prospects for future years seemed far from bright. There were significant upturns in the quantity and value of mineral commodities produced, traded, and consumed in 1983, and many nonfuel mineral prices advanced, although the price advances in current dollars in most instances barely compensated for inflation. The pattern of investment in exploration and development of new mining ventures and new plant construction reflected virtual industry-wide concern that substantial upturns in demand for mineral commodities in the near future were unlikely, at least for most large volume products. The world oil glut continued despite cutbacks in production, and substantial stocks of many other mineral commodities mitigated against growth in total productive capacity, at least among market economy nations. In these countries, development activity at both mines and plants was confined largely to programs aimed at substituting new, more efficient installations for old, uneconomic or marginally economic plants. Among the centrally planned economy countries, the pattern was somewhat different on the whole, but even there, growth in total productive capacity was evidently somewhat restrained, although it seemed questionable whether the restraint was a function of intentional planning or simply an inability to accomplish planned programs on schedule. International political events, particularly the Iran-Iraq war and the unstable situation in the eastern Mediterranean countries (Lebanon, Israel, and Syria), continued to adversely affect mineral industry activities in those areas. Similarly, the internal and international conflicts in Central America negatively influenced mineral industry operations there. In Afghanistan, it appeared that there was some upturn in the very modest mineral industry operations, but industry activities there undoubtedly continued to be affected by confrontations between the Soviets and the local citizenry.

Jan 1, 1985

By Ta M. Li

How will phosphate producers in southeastern Idaho fare with growing governmental regulations and environmentalism of the late 1970's? With a similarity that is reminiscent of the battles between the coal industry and environmental-conservation groups earlier in the decade, Idaho's future growth and a nation's need for phosphate fertilizer products remain uncertain. The catalyst that brought the issue to the forefront was the preparation of an Environmental Impact Statement (EIS) addressing the development of phosphate resources in southeastern Idaho. Although the final EIS was published in August 1977, resolution of rational and orderly growth in this potentially vital region remains stifled as Secretary of the Interior Cecil Andrus virtually "sits" on it.

Jan 1, 1978

By M. S. M. Aljuhani

In this paper, one of the human factors that affect productivity in an underground gold mine in Saudi Arabia was investigated and analysed for the purpose of improving productivity. The human factor that was investigated is labour utilization and labour productivity. In the selected mine, labourer?s performances were measured carefully. It was found that in this mine, workers spend only 65% of the shift time in a productive work, and they spend 35% of the shift time in non-productive activities. As a result, recommendations were presented to enhance productivity in the selected underground gold mine by enhancing labour utilization.

Jan 1, 2002

Mineral liberation data are routinely obtained for a wide variety of applications, including ore characterization and characterization of various metallurgical test products obtained in bench-scale laboratory testwork. Newmont Mining Corporation owns several properties in the Carlin Trend containing refractory gold ores. These ores are generally difficult to treat and have to undergo several processing stages for gold recovery. At Carlin?s Mill 5 operation, flotation is used to pre-concentrate some of these difficult ores to produce a sulfide concentrate to feed the roaster. It is of interest from a flotation perspective to be able to study the floatability of pyrite, arsenopyrite and arsenian pyrite, since these minerals all have different quantities of gold associated with them, and have to be recovered to ensure a successful separation has been achieved. In this paper, a detailed MLA study on several Carlin ores was undertaken on samples from flotation tests, using air or nitrogen as flotation gas, specifically to study the differences in floatability characteristics, which ultimately impacts overall gold recovery. I

Jan 1, 2009

ME?s Arizona Conference was held at the Hilton El Conquistador resort in Tucson on Dec. 2 and 3, 2007. The annual conference is organized by the Arizona Conference Board of Directors, which represents SME sections in Arizona and adjacent areas. The conference provides an opportunity for individuals and corporations associated with mining in the region to get together once each year to discuss the status of the industry. The 2007 meeting featured a keynote address, a distinguished lecturer and more than 25 technical papers that were presented in seven sessions. The sessions included environmental, geology, safety, metallurgy, mining, new projects and a special session on Mexico. Topics covered included mine closure, sustainable mining, exploration methods, health and safety issues, mining equipment and drilling. Much of the discussion at the conference concerned major new developments in the region?s copper mining industry. For example, Freeport-McMoRan?s new Safford Mine and BHP Billiton?s Pinto Valley restart were the topics of technical presentations. There was also much discussion among the attendees on the current and future price of copper, community relations, education issues and recruitment concerns. At the time of the conference, the price of copper hovered around $3.30/lb, up considerably from the 61 cents/lb in late 2001, when the industry was being challenged by world market conditions and a weakened domestic economy. Since then, strong demand from China helped push copper prices to record levels that at one time reached as high as $4/lb. The general consensus among the attendees is that the current price of around $3.30/lb will continue through 2008. Most attendees also expect increased corporate investments in the industry to continue. Copper mining in Arizona has been a major industry since the 1800s. In 2007, Arizona was the leading copper-producing state in the United States and produced more than $5 billion worth of copper. The copper mining industry in Arizona also produces byproduct gold, silver and molybdenum. Arizona is the second largest molybdenum producer in the United States.

Jan 1, 2008

By Ian MacKenzie

Over the past twelve years, professionals such as architects, engineers, accountants, and attorneys have not had to pay a great deal of attention to GST. The fees charged to clients (outputs) have not been subject to GST, but they have had to pay GST on al purchases of materials and taxable services relating to their activities.

Jan 1, 1990

By Mike Sapiro

"Heath Steele Mines is a base metal producer situated near Newcastle, N.B. presently treating 3500 TPD of complex Cu-Pb-Zn ore. The ore consists of massive fine grained sulfides averaging I. 1% Cu, 1.6% Pb and 4.5% Zn.The original mill started in 1956 at 750 TPD and was successively expanded through 1500 to 3000 TPD in 1969. In 1972 an expansion to 4000 TPD was initiated. It was planned to obtain the maximum benefit from equipment and manpower by adding some process equipment, instrumentation, an on stream analyser, and a process control system. The benefits from this approach could be greater than normally expected, because of the complex metallurgy of this ore.IntroductionThe crushing plant is of conventional design with two 5 ½ ft, Symons cone crushers with the crushed ore screened to -7/8 inch on a 61 x 16 1 Al I is Chalmers vibrating screen and stored in four 1000 Ion bins. There are two para I lei grinding circuits, each one consisting of the following: one Rod Mill in open circuit, one Ball Mill in closed circuit with two 20"" Krebs cyclones, and one Ball Mill in closed circuit with three 15"" Krebs cyclones, Al I the Mills are 9' x 121 Al I is Chalmers Mills. The secondary cyclone overflow from each grinding circuit is thickened and combined to form flotation feed. The final product is 65% - 400 Mesh. Two regrind mills have been installed as part of the expansion."

Jan 1, 1977

By M. Ge

Pattison Mine is a small sandstone mine located in Iowa. The sandstones produced by the mine are not common construction and aggregate materials. The stones are used to produce a special type of sand for hydraulic fracturing, a critical technique for recovering tight gas and shale gas. These sandstones are very different from the minerals and rocks which have been studied extensively in mining. On the one hand, they are brittle as characterized by an unusually high friction angle, up to 69°, and steeply curved failure envelopes. On the other hand, they are friable, possessing extremely low, and in most cases zero cohesion. The scarcity of the ground control techniques for this particular mining environment has created many difficulties for the mine operators. In order to resolve these problems, a research program was set up by the mine and Missouri University of Science and Technology. This paper discusses the preliminary results of this investigation.

Jan 1, 2012

By R L. Brathwaite

In New Zealand, volcanogenic massive sulfide (VMS) deposits are found in three main geological environments associated with: 1.   ophiolitic basalts of Oligocene age in Northland and East Cape (eg Pupuke, Pakotai, Parakao and Lottin Point); 2.   with chert and pillow lava in greywacke sequences of Permian-Jurassic age (Torlesse and Waipapa terranes; eg Kawau Island, Te Kumi and Maharahara) and their metamorphic equivalents (Haast Schist; eg Moke Creek and Waitahuna); and 3.   with greenschists (metabasalts) and metaserpentinite of Permian-Triassic age (Ponamu Ultramafics) in Westland (eg Bowen and Wilberg ranges). The deposits consist of small lenses of disseminated to massive sulfide minerals, mainly pyrite and chalcopyrite. Small quantities of copper ore were mined from some deposits in the 1800s (eg Kawau Island from 1846), with the last mining at Parakao from 1961 to 1966. Several deposits have been recently examined for their gold potential with assays on sulfide rock samples as high as 75 g/t Au (Lottin Point).

Jan 1, 2005

By Glen Frank, David R. Chapman

Determining the number of boulders and cobbles that will be encountered in the tunnel envelope is one of the most difficult problems confronting the geotechnical engineer in the design of tunnels in glacial terrain. This issue is very important to the contractor, both in determining what methods will be used to construct the facilities and the advance rate that can be achieved for the chosen construction methods. The cost of constructing tunnels by pressurized face tunneling techniques is very sensitive to accurate characterization of the very coarse fraction (large cobble and boulder sized clasts), and no standard method is current available for characterizing boulders and cobbles. Careful use of large diameter borings and the sampling and analytical techniques outlined in this paper can provide a means to answer this difficult question. By performing large diameter borings and carefully recording and sampling the cobbles and boulders encountered, an estimate for the amount of these materials present in the formations sampled can be provided. Using this method allows the designer to communicate the expected geologic conditions to the prospective bidders in a manner that is both definitive and defensible. This paper describes the method as it was used in conjunction with the design of a large diameter sewer tunnel in the Columbus, Ohio area.

Jan 1, 2005

By Catherine N. Mulligan

Thickening of mine tailings is a relatively new concept for their sustainable management. Removal of water from the tailings to form a paste instead of slurry disposal decreases environmental and geotechnical concerns. As the use of these pastes is relatively new, their behaviour requires investigations such as liquefaction and seismic stability, freeze-thaw behaviour, consolidation and leachate characterization. Slurry density, ore type, particle size distribution, specific gravity and environmental conditions can all influence paste characteristics. In this paper, the effect of the above-mentioned parameters is examined. New developments in water removal, and additives (such as flocculating agents, cements, organics, fertilizers, etc) leading to low moisture content tailings are reviewed, and the potential for thickening to enable sustainable management of mine tailings is discussed with respect to storage volume requirement, use of virgin land, consolidation of the tailings, land use after decommissioning.

May 1, 2007

By Ray W. Ballmer

"For his leadership in developing and managing large, complex, and technically innovative mines, particularly the outstanding and successful Bougainville mine and for his lecture, 'The Moving Targets of Mine Development '. " Recipient of the 1981 D. C. Jackling Award

Jan 1, 1982

By S. K. Murphy, S. M. Spottiswoode, A. M. Milev, D. Geyser

A portable, stand-alone instrument especially designed for recording strong ground motion was used in this study to create a large database of peak particle velocities measured underground. A total number of 39 sites located in stopes mining Carbon Leader and Ventersdorp Contact Reefs were investigated. Peak particle velocities whith values up to 3 m/s were recorded at some sites. The data recorded on the skin of the excavations were compared to the data recorded by the mine seismic networks to determine the site response. The maximum site response was obtained for source radii of between 5 m and 30 m and events locating within 200 m of the site. The extreme values of peak particle velocities were obtained in cases were the face-area lay within the source radius. Un instrument portable unique spécifiquement conçu pour enregistrer les mouvements dynamiques des terrains, a été utilisé dans cette étude pour créer une base de données importante sur la vélocité maximum des particules, mesurée en souterrain. Un nombre total de 39 sites situés dans les excavations exploitant les récifs appelés ‘Carbon Leader et Ventersdorp Contact Reefs’, a été investigué. Une vélocité maximale avec des valeurs allant jusqu’ à 3 m/s a été enregistrée sur certains sites. Les données enregistrées sur le bord de l’excavation ont été comparées aux données enregistrées par les réseaux séismiques de la mine pour déterminer la réponse du site. La réponse maximum du site a été obtenue pour des sources de rayons entre 5 m et 30 m et des évènements situés dans les 200 m du site. Les valeurs extrêmes de vélocités maximales ont été obtenues pour les cas où la zone de face se trouve à l’intérieur du rayon de la source. Ein mobiles, alleinstehendes Instrument, speziell entworfen um starke Formationsbewegungen aufzuzeichnen, wurde in dieser Studie verwendet um eine große Datenbank von Partikelspitzengeschwindigkeiten, die Untertage gemessen wurden, aufzuzeichnen. Eine Gesamtanzahl von 39 Aufstellungsorten in den Schichtabbauorten vom Carbon Leader und Ventersdorp Contact Reef wurden untersucht. Partikelspitzengeschwindigkeiten mit Werten bis zu 3 m/s wurden an einigen Standorten aufgezeichnet Die an der Oberfläche des Grubenraumes aufgezeichneten Daten wurden mit jenen Daten verglichen, die vom seismischen Netzwerk der Grube notiert wurden, um die örtliche Reaktion des Standortes zu bestimmen. Die maximale Standortreaktion wurde für Ursprungsradien von zwischen 5 m und 30 m erhalten und Ereignissen die sich innerhalb von 200 m vom Standort befanden. Die extremen Werte der Partikelhöchstgeschwindigkeiten wurdenin jenen Fällen erreicht wo sich der Abbaubereich innerhalb des Ursprungsradiuses befand.

Jan 1, 2003

By X Meng, W. A. Hustrulid, M. K. McCarter

Rock excavation in both surface and underground mining is largely accomplished using the drill and blast technique. At the perimeter of such excavations, cautious blasting procedures are often employed to minimize unwanted damage to the remaining rock. Of the several different techniques available, the use of explosive charges with a diameter smaller than the holes in which they are introduced (so-called decoupled charges) is the most common. In spite of the long and widespread use of the technique, a technically sound basis for relating the borehole wall pressure to the explosion pressure is still lacking. Such a relationship is required for optimal design

Jan 1, 2005

By Peter G. Kovalchik, Lawrence W. Scott, Thomas H. Dubaniewicz, Mark A. Fuller

Mine trailing cables operated above safe thermal limits can cause premature insulation failure, increasing electrocution and fire hazards. Previous U.S. Bureau of Mines Pittsburgh Research Center research showed that, under static test conditions, electrical current levels permitted under present regulations may not limit cable temperatures to less than the 90 °C rating of reeled trailing cable. Continuing research under the National Institute for Occupational Safety and Health (NIOSH) addresses thermal characteristics of reeled trailing cable under dynamic test conditions more representative of field conditions, where operators constantly reel in and pay out cable. This research is in support of efforts by industry associations and the Mine Safety and Health Administration to establish safety guidelines for cyclically rated reeled machines. This paper describes a unique approach to measuring temperatures within reeled cable under dynamic test conditions. Fiber-optic sensors embedded within the metallic conductors measure temperatures at 1-m intervals along the entire length of cable. Temperature measurements are reported to be accurate to within 1±° C. The test setup requires access to only one end of the trailing cable, allowing researchers to freely reel in and pay out cable while temperature measurements are made, simulating field conditions. Manufacture of a fiberoptic-embedded trailing cable is described, along with initial test results that indicate the fiber-optic approach is viable.

By J. D. Sargent

Selenium might be described as a paradoxical element, being either a metal or a nonmetal, a conductor or nonconductor, amorphous or crystalline, colorant or decolorant, and a hydrogenator or dehydrogenator. Selenium was discovered in 1817 by the Swedish chemist, Berzelius, while studying flue dust from the lead chambers of the sulfuric acid works at Gripsholm, Sweden, The ordinary stable form of selenium is a crystalline, grayish solid with semi-metallic luster. It melts at 217° C., boils at 684.8° C., and has a density of 4.79.

Jan 1, 1955

By D. Van Tonder, C. Edwards

ABSTRACT Solvent extraction is used in many acid leach uranium circuits to upgrade and purify the uranium-bearing solution prior to final product precipitation. A number of strip options are available to recover the uranium from the loaded organic. This paper compares seven of these options on the basis of typical capital and operating costs for the solvent extraction circuit and downstream uranium processing and also considers other related issues. The aim is to provide an objective comparative assessment of these options that could be used as a qualitative guide in process selection or improvement.

Jan 1, 2013

By Brian W. Stump, David P. Anderson

Identification of seismic events detected under a Comprehensive Test Ban Treaty requires a clear physical understanding of the different types of seismic sources including mining explosions, rock bursts, mine collapse and small, shallow earthquakes. Constraint of the operative physical processes in the source region and linkage to the generation of seismic waveforms with particular emphasis on regional seismograms is needed. In order to properly address the multi-dimensional aspect of data sets designed to constrain these sources, we are investigating a number of modern visualization tools that have only recently become available with new, highspeed graphical computers that can utilize relatively large data sets. The results of this study will provide a basis for identifying important physical processes in the source region that contribute to regional seismograms.

Jan 1, 1995

By J. B. Zadra

Much has been published by various investigators on the use of activated carbon for adsorbing precious metals from cyanide solution and pulp. For the benefit of the reader, a list of these earlier publications appears at the end of this report. The present paper deals only with a process for extracting gold from gold-laden carbon and re-use of the de-adsorbed carbon. At the Getchell mine, Redhouse, Nev., experiments have been in progress for several years concerning the use of activated carbon to adsorb gold from their slime circuit pulp. The experimental work has been successful. Their practice has been to ship the gold-laden carbon to a smelter for treatment, which meant the total loss of the carbon in addition to smelter and freight, charges, all of which proved costly and wasteful.

Jan 1, 1950

Draglines are one of the largest land-based equipment moving across the earth. They typically ranging in size from2.5 to 6.5 kt (2,750 to 7,100 st). Their size, though, makes them difficult to maintain. Recently, G&S Engineering Services used an Enerpac synchronous hydraulic lifting system to lift a 3.2-t(3,500-st) dragline at the Curragh Mine in Queensland, Australia’s Bowen Basin.

Jan 1, 2004