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By W. S. Fyfe

Gold is mobilized and precipitated in a wide variety of environments ranging from those of weathering and biological phenomena, to pluton emplacement to deep metamorph ism . But it appear that pervas ive leaching of large rock volumes fo llowed by the focussed di charge of typically low salin ity flu ids is frequently involved. There are great gaps in our knowledge, particula rly with re pect to gold in very high temperature fl uids generated at near Moho depths. But uch flu id may play an important part in Archaean pluton associated lode gold deposits whe re ultra high temperature fluids, rich in C02-CO-COS, may be associated with magma underplating and crustal assi mil ation processes (sag subduction) associated with very den e ult ramafic magma . Other environment with great potential include those of major thru t fau lt and strike slip fa ult s where large quant ities of fluids are mobilized .

Jan 1, 1986

By T. W. Johnson

One of the common methods of increasing recovery of oil from partly depleted oil sands is to inject natural gas, air, or air-gas mixtures into the sand, thereby supplying energy to move oil into the well bore. Where natural gas is not available, air or an air-gas mixture is used as the repressuring medium. Air-gas mixtures are obtained from the casing-heads of oil-producing wells in the areas repressured with air or air-gas mixtures and consist usually of varying amounts of the hydrocarbon gases, nitrogen, oxygen, and carbon dioxide. Laboratory experiments have been conducted by the Bureau of Mines to determine the effect of air on crude oils.4/ In these experiments the crude oils were oxidized by the air, and the degree of oxidation depended not only upon the chemical composition of the crude oil but also upon the duration and method of contact between the oil and air, the temperature of the fluids and the concentration of the oxygen. When the crude oils were oxidized the following results and changes in the oils were obtained:

Jan 1, 1937

By T. W. Johnson

One of the common methods of increasing recovery of oil from partly depleted oil sands is to inject natural gas, air, or air-gas mixtures into the sand, thereby supplying energy to move oil. into the well bore. Where natural gas is not available, air or an air-gas mixture is used as the repressuring medium. Air-gas mixtures are obtained from the casingheads of oil-producing wells in the areas repressured with air or air-gas mixtures and consist usually of varying amounts of the hydrocarbon gases, nitrogen, oxygen, and carbon dioxide. Laboratory experiments have been conducted by the Bureau of Mines to determine the effect of air on crude oils.4/ In these experiments the crude oils were oxidized by the air, and the degree of oxidation depended not only upon the chemical composition of the crude oil but also upon the duration and method of contact between the oil and air, the temperature of the fluids and the concentration of the oxygen. When the crude oils were oxidized the following results and changes in the oils were obtained:

Jan 1, 1937

By Timothy J. Orr, Jami M. Girard

A NIOSH study on occupational deaths between 1980 and 1989 indicated that in the United States, mining had the highest average annual fatality rate (3 1.9 per 100,000 workers) of any other major industry. Since "lack of training" was often cited as the primary cause of accidents, NIOSH has been investigating new methods for effective training. One such method is the use of low- cost, desktop computers to simulate a virtual mining environment. Computer-based training offers several advantages over conventional training because the computer programs provide a three- dimensional environment that allows the trainee to practice using evacuation routes, encounter mining hazards, and view mining operations without being exposed to any real danger. One major focus of the project is mine escapeway multiuser training using desktop virtual reality programs. Researchers have imported mine maps into the software for the purpose of practicing actual evacuation routes and procedures. Various scenarios for evacuation can be practiced in a three-dimensional computer simulation of the mine in a disaster situation, complete with smoke, fire, and other dangers. Depending on the trainee's job description (i.e., foreman, shift boss, beltman, etc.), certain tasks need to be performed in addition to navigating primary and/or secondary escape routes. Each scenario allows for individual or team-based training and provides a means to educate mine workers in hazard recognition and hazard avoidance. Using this program, mine workers can practice evacuating various mine layouts without the danger and expense associated with escapeway training in an actual underground mine. Each scenario can be changed to test the trainee's reaction in a variety of circumstances and run many times so the trainee can practice concepts. This training experience will help reinforce the knowledge acquired during more conventional classroom instruction, and the inherent flexibility of the program allows training materials to be tailored to meet the specific requirements of individual mines.

Jan 1, 2002

By Andrew T. Zador

The growing demand for energy combined with the need to protect and preserve the environment have become prime considerations in the design of efficient coal handling ports and their associated stockpiles. The transportation system is analogous to a connected chain which originates at the mines and terminates at steel mills or power plants, in which the port and the stockpile reserves are a vital link. Railroad transportation costs can be minimized by rapid discharge of the cars which, in turn, requires that an adequate stockpile system be available. Ocean transport costs can be minimized by having an efficient high capacity ship loading system and sufficient quantities of coal on hand -all of which also requires an efficient stockpile system to meet shipping demands. The connector between the two modes of transportation, therefore, is the port stockyard. It is here at the interface that optimization of land utilization and materials handling equipment results in a total transportation chain that can operate as a smooth efficient system. Multiple origins of coal require the simultaneous handling of large quantities of coal of many grades. Railroad transportation logistics often limit and define the incoming arrival patterns and limited rolling stock often require priority treatment for railroad operations. The physical limitations of prime ocean frontage require that coal stockpiles be built close to residential or industrial areas which entail strict environmental controls. Large capacity, enclosed coal stockpiles for ocean shipping have not yet been considered feasible but may be forthcoming in the near future. Several have been analyzed.

Jan 1, 1978

By J. Brune, P. J. Coleman, L. Martini

Research in the field of mining safety and health in the United States plays an important part in protecting the lives of miners. The National Institute for Occupational Safety and Health (NIOSH) Mining Program conducts surveillance, studies and developmental work aimed at improving the safety and health of miners. With recent reviews of the Mining Program by the National Academy of Sciences and the Mining Program response (NIOSH, 2008), the importance of setting goals, conducting high quality engineering and scientific research and evaluating the outputs, outcomes, relevance and impacts of these projects has been reemphasized. Surveillance of reported injuries is a first step in deciding on research directions and in designing specific projects. Groups of injuries often share features and attributes that suggest common causes and may respond to similar preventive efforts. Identifying groups of injuries also serves to prioritize intervention efforts. The Mine Safety and Health Administration (MSHA) Accident and Injury database (MSHA, 2008) provides individual case reports of mining injuries, illnesses and certain no-injury accidents (events such as roof falls that stop mine production or miners’ activities for more than one hour). This database is an indispensable resource for researchers and stakeholders needing information on the statistics of these events. From an epidemiological perspective, research projects target groups of miners at risk due to specific patterns of work, equipment, mine settings and the management of safety and health in their mines. Incidence rates are provided by the MSHA data for selected variables, such as surface/underground location, standard industrial classification and state. While incidence rates are the preferred measure for all variables, denominators are not typically available; for example, to more clearly understand the data about injury by occupational type, it would be necessary to conduct demographic surveys. A current survey of the demographics of the mining industry should be complete by 2010, which will allow incidence rates to be developed for a number of variables such as age, occupation and experience. This survey will provide the first update of its kind since the first survey was conducted in 1985. This report describes an alternative method of analyzing and presenting MSHA data for the purpose of identifying high-cost, high-severity injuries and illnesses. Researchers at the NIOSH Spokane Research Laboratory (SRL) developed programs to find the top five most frequent accident classes, natures of injury, types of accidents and other selected variables from the MSHA database. Studying these variables gives a cross-sectional snapshot of the most frequent groups of injuries within a commodity, regional group or time period, and allows researchers to quickly understand developing patterns for new research projects. The primary benefit of this approach is to

Jan 1, 2009

By English W, Poppit I

COALEX Pry Limited operates two underground steaming coal mines on the western edge of the Sydney Basin near Lithgow, New South Wales. Baal Bone Colliery uses longwall technology for an output of over two million tonne/year while Clarence Colliery currently uses continuous miners and breaker line supports for an output of two million tonnelyear.A computerised geological database and modelling system has been implemented to service these mines routinely, as well as several outlying prospects. The database is constantly upgraded for drillhole information, surveyed spot levels on the surface and underground, quality sampling details, surveyed mine workings and geological mapping. This information is edited on a routine basis, allowing dynamic modelling of key aspects of geology for ongoing operations.

Jan 1, 1991

By L L. Kuhar

The AMIRA International P843A Geometallurgical Mapping and Mine Modelling (GeMIII) project is an interdisciplinary research collaboration between 17 global mineral companies and four research organisations aimed at providing support for the emerging industry trend of geometallurgy. The main aim of the project is to develop predictive geometallurgical indices which can be incorporated into a resource block model to maximise the commercial value of an orebody and to minimise the social and environmental impact of mining operations.Researchers at the Parker Centre/CSIRO have been focusing on the development of predictive hydrometallurgical indices for the GeMIII project via rapid, small-scale, cost-effective tests and protocols for comparative ranking of attributes relevant to leach performance. The focus of the small-scale leach tests has been to determine the leach index (relative indication of leach performance), recovery, impurity deportment, reagent consumption, effect of size/degree of liberation and mineralogy of samples for their relative ranking. Predictive tests for heap leach hydrology (related to agglomerate characteristics) and slurry rheological behaviour are also being developed.

Sep 5, 2011

By F. E. Griffith, C. H. SEELING

Cardox blasting is used widely in coal mines in the United States . A model of a Cardox blasting device was approved by the Bureau of Mines subject to certain conditions and limitations , and the approval was extended to other models from time to time . Certain special hazards are entailed in the use of Cardox as with explosives . One of these is flying shells . In some blasts , the Cardox shell is violently ejected from the borehole and flies like a projectile , frequently ricocheting off solid objects and striking points considerably off the line of its initial flight . Flying shells have been known to pierce the webs of structural - steel beams , to pass through both sides of allsteel mine cars , to be driven through stout hardwood timbers , to knock out timber sets , to damage loading equipment , and to break or short - circuit power lines . A considerable number of shot - firers and other workers have been struck by flying shells and killed or injured . Accidents from this cause , although not as frequent as other types of mine accidents , are usually serious , closely approximating accidents caused by blasting with ordinary explosives . The increasing number of such accidents prompted a Bureau of Mines field investigation of possible methods of preventing dangerously violent ejections of Cardox devices . This report contains pertinent data collected during the investigation and describes methods tested and discarded as well as the development and proof of an apparently satisfactory method .

Jun 1, 1943

By M Warnken

Major cities are not only the focal point for AustralianÆs work, leisure and homes, they also are the focal point for the flow of resources into the built environment, motor cars and transportation and urban consumables. The steady increases in æstockÆ and waste generation, in line with GDP growth, means that cities will become the mine sites of the future if the inherent value is recovered from these materials at end of life. The urban waste stream can be characterised as containing approximately nine per cent hydrocarbon-based materials; 57 per cent biomass-based material; 28 per cent fully mineralised materials that are inert, five per cent metals and less than one per cent of problematic materials that are potentially hazardous and toxic. In order to convert these wastes into value added inputs into the economy, a number of technological interventions are required. These æurban waste mining techniquesÆ revolve around source separation and material streaming. One issue that needs to be overcome when determining which mining technique to implement, is identifying the option that will deliver optimal value, both from a financial and a sustainability perspective. The difference between embodied energy and calorific value is a case in point. Highest net resource value (HNRV) is a concept that can assist in choosing between different resource recovery options. The assessment can be done at a strategic level, or can be used to work out material specific issues. For example, used tyres can be recovered for their energy content at an approximate cost of $120 per tonne, whereas mechanical processing of used tyres can deliver a net benefit of $192.

Jan 1, 2006

By William D. Mayercheck

The U.S. Bureau of Mines is conducting research aimed at providing technology for a low-cost, high-recovery, environmentally acceptable mining system to recover the vast thin-seam coal reserves existing in the mountainous areas of the Appalachian region in the Eastern United States. As part of this research, the Bureau is evaluating new techniques to address these coal resources. This report summarizes the results of a worldwide technical search on thin-seam coal mining, the formulation of various methodologies for mining mountaintop thin seams, and the implementation and status of a physical model test program to validate and further develop the most promising concept-the "roof-fall-tolerant" mining system.

Jan 1, 1990

By Manuel Gomez

Carbon number distributions were obtained for tar acid fractions from five low-temperature tars by low-ionizing voltage mass spectrometry. Quantitative data for phenols representing seven structural compound types were examined by statistical analysis. It was shown that for the phenols discussed, the data could be represented by regression equations expressing phenolic concentration as a function of the reciprocal of the carbon number and the carbon-to-hydrogen ratio of the parent coal. The total concentration of each structural type present was found to depend on the molecular weight and boiling point of the initial member of the group. Carbon distribution data for the tar acid fractions studied support the view that low-temperature tars contain the same chemical compounds but in different proportions.

Jan 1, 1965

By Luis Carrera Naranjo

El presente texto señala la topografía, geología regional, estratigrafía, fisiografía, caracteres morfológicos, mineralógicos y genéticos, y la clasificación según su proceso de formación del yacimiento de la región Morococha. La topografía de esta región es variada y rica en cuanto formaciones geológicas se refiere, dado sus orígenes y edades respectivas. Su estratigrafía comprende una columna geológica, la cual está compuesta por rocas sedimentarias, y extrusivas que van desde el periodo Cuaternario hasta el Terciario. Las formaciones encontradas en la región son las filitas excelsior, volcánicas Catalina, formación Mitu, calizas Potosí, formación Santo Toribio-Buena Ventura, formación Machay, las capars rojas de Casapalca, la diorita de Anticona y monzonita cuarcífera de Morococha. Asimismo tiene dos sistemas de fallas: longitudinal y transversal. Las especies metalíferas de mayor abundancia son: la pirita, tenantita, tetrahedrita, chalcopirita, enargíta, blenda, magnetíta y galena. Mientras que las de menor abundancia son: estefanita, especularita, phrotita, marcasita y muy raramente: aíkenita; burnonita, cubanita, jamesonita, luzonita y molibdenita. Finalmente, entre las características estructurales de depósito tenemos: las vetas y los mantos, considerando entre los mantos algunos subtipos o variedades estructurales. También existe una tercera clase de estructura de depósitos minerales, que son lo que están constítuídos por varios depósitos agrupados en forma localizada y se conocen como el "0re -Clusters" o "Archipiélago".

Jul 20, 1960

By S. Dey, C. Bhar, S. K. Mandal

Loading and hauling of ore and waste are the key operations of an opencast coal mine and entail a high operational cost. The productivity of a mine can be increased by reducing the cycle time of loading equipment as well as utilizing dumpers optimally. In this paper we discuss the impact of rock type, bucket fill factor, rock fragmentation, the height of the cut, and angle of swing of the bucket on shovel performance. A time study is conducted on shovels in an opencast coal mine with experimental blasts of rocks to assess the impact of different factors on the performance of the shovel. Based on the data, the authors applied multiple regression (MR) and artificial neural network (ANN) techniques to develop different models for the prediction of the shovel cycle time. Developed models are validated by comparing the predicted data with actual field data. With the help of the best model, the plausible fleet size is determined in order to utilize the shovel and dumper optimally and to improve the performance of shovel–dumper operation.

Oct 1, 2022

By Edward J. McNamara

Sulphur as an element has been used for centuries. The technique of storing, handling and transporting it in its various forms has changed through the years. Freeport Sulphur Company, a division of Freeport Minerals Company, has produced sulphur since 1912. The first storing and transporting of this product as a liquid began in 1947. Significant environmental problems occurred in the handling of solid sulphur in the late fifties and early sixties. Since the sulphur WAS produced in the liquid form and the major customers used it in the liquid form, it became obvious that a liquid transportation system was the solution. The liquid sulphur delivery eliminated the dusty and hazardous handling problems and the contamination of the sulphur by dirt, acid, moisture and other materials. The remelting by the customer to use the sulphur is thusly eliminated with a savings in energy. In addition, this change in the mode of handling permitted a broad development of new sulphur mines in the marshy coastal area of Louisiana and offshore in the Gulf of Mexico.

Jan 1, 1978

By B. Genc

Improving student success rates without compromising the quality of graduates is one of the biggest challenges expanding university programmes are facing in South Africa. By establishing a new Mine Design Laboratory (MDL) for higher learning in Mining Engineering, the School of Mining Engineering at the University of the Witwatersrand (Wits Mining) has achieved one of the important goals in its five-year strategic plan, i.e. to improve throughput in all years of study. Although the establishment of the laboratory has been a costly exercise, results so far have shown an improved success rate in most subjects taught in the facility. This paper outlines the design and equipment of the laboratory, the facilities incorporated, a comparison with the old laboratory, and the performance of students?all of which indicate how important it is to have proper facilities to improve the teaching of, and learning by, large classes. Through this initiative, Wits Mining has taken an important step that will contribute to addressing the skills shortages in the mining industry.

Jan 1, 2012

By S. Averill, B. Schreiner, V. Sopuck

The La Ronge. Kisseynew, Glennie Lake and Flin Flon domains. the main focu for gold exploration in the southeast part of the Saskatchewan Shield, were subject to continental glacial ice advances from the northeast during the Quaternary. Based on forty-four auger hole along with surficial mapping, the general Quaternary stratigraphy in this area is observed to be composed of a lower till unit , an overlying stratified unit of glaciofluvial sand and gravel and/or a glaciolacustrine silt-clay unit. an upper till. and an upper tratified unit. The lower till is commonly found throughout the geological domains except where it has been eroded in glaciofluvial or fluvial channels. Glacial Lake Agassiz fo rmerly covered most of these prospective domains. The lacustrine deposits associated with the lake impede surficial geochemical surveys including soil. lake sediment. and biogeochemical surveys. The approximate extent of clay cover can be predicted from beach elevations. For instance. in the Waddy Lake area. clay i not known to occur above about 1,400 feet (425 m) elevation. Exploration techniques are hampered by clay in at least one third of the volcanic belt. Thi s influence is indicated by the fact that nearly all gold prospect found to date are located above 1,400 feet (425 m) while the area of clay cover is vi rtually unexplored. The upper till i related to a minor ice readvance. This till is the medium often sampled during soil surveys in the area . lts value as a geochemical ampling medium is dependent on the extent of erosional contact with bedrock highs on the lower till. Those areas which are relatively free of lacustrine and fluvial deposits are those where surface geochemical methods work best. In the Waddy Lake volcanic belt approximately 25-50% of the area may be suitable for surficial surveys. The area of the Star Lake prospect occurs above the 1,500 foot (460 m) elevation and was not covered by Lake Agas iz. The effectivene of till sampling as a surface sampling medium was tested in those areas above the clay level. Till orientat ion surveys were carried out at the Star Lake property and the Tower Lake prospect (Waddy Lake area) within the La Ronge Domain . Gold grain counts and analy es of heavy mineral concent rate from 7 kg surface ti ll samples were used to delineate dispersion trains down-ice from mineralization. In addition, the clay fraction and a 30 g (-80 mesh) subsample from the same till sample, were analyzed for gold . In the Star Lake area, ice direction is subparallel to the strike of several narrow northeast trending auriferous structures. arrow dispersion trains down-ice from known

Jan 1, 1986

By Noel A. Warner

Modern steelmaking is based on direct use of oxygen in high intensity batch reactors. A totally new approach is proposed in this paper, based on the view that pursuit of high intensity is unlikely to lead to successful coal-based continuous steelmaking. By substituting carbon dioxide and water vapor as the oxidants rather than using oxygen directly, the intensity is greatly reduced. Accordingly, subsurface formation of carbon monoxide bubbles can be avoided by careful manipulation of the three participating rate processes, gaseous diffusion, interfacial chemical kinetics and liquid phase mass transfer. Steelmaking can then be carried out without explosive ejection of molten droplets and the generation of micro-spray but rather in a controlled and fume less fashion. The vital component is the introduction of generic melt circulation technology. Three melt circulation loops in series are envisaged. Starting with a composite feed of iron ore fines, pulverized coal and lime flux, a metallized solid raft floating on molten iron is propelled out of the ironmaking loop onto the first of two downstream steelmaking loops. In the first, a liquid slag is formed, primary decarburization is undertaken not with oxygen but rather with CO2 and H2O and the melt is desulfurized. The semi-product stream enters the third melt circulation loop, where open-channel decarburization is effected along with dephosphorization to yield a low carbon steel product. Alternatively, the melt leaves the last loop to irrigate a packed tower countercurrent to argon at around 100 mbar to continuously produce ultra-low carbon (ULC) steel.

Jan 1, 2003

By G. L. Gates

The Bureau of Mines in cooperation with the City of Long Beach) Calif.) studied some physical factors effecting the deposition of barium sulfate scale in oil-well rotary pumps. Freshly formed barium sulfate was obtained by combining sulfate in sea water with barium from a barium chloride solution. The rate of scale deposition was measured quantitatively by weighing the pump impellers and diffusers. The results of the tests showed that coating the impellers with plastic significantly reduced the rate of barium sulfate deposition.

Jan 1, 1967

By Francesco Chiappalone, Filippo Azzarà, Raffaele Aliberti, Daniele Nebbia, Lance Waddell

As part of the 3RPORT and NEBT Projects, 5-mile Combined Sewer Overflow Tunnels were excavated with a 19 ft diameter Slurry and 26 ft diameter EPB Tunnel Boring Machines. Due to the difficult geological and hydrogeological conditions, both tunnels were excavated maintaining a ground support pressure between 2 and 5.5 bar imposing significant challenges to the projects. The first part of the paper describes the general characteristics of both projects while the second part focuses on the challenges and technical details of the pressurized breakthroughs that took place in deep shafts excavated in urban environment as part of the projects.

Dec 1, 2022