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By L. Linzer, J. Oelofse, T. Rangasamy

Extraction of isolated blocks of ground with elevated levels of stress and/or seismicity is a common occurrence in South African gold mines. Isolated blocks of ground that are divorced from the main orebody and are bound by complex, dip and strike parallel, non-persistent geological structures dominate the Klerksdorp gold fields. No quantifiable methods exist to assess the risk associated with mining these and other classes of remnants. A case history, from a gold mine that planned to extract three remnant blocks hosted in a large complex fault system, is used to illustrate the decision making process based on a combination of underground observations, numerical and seismic techniques. Simple risk estimation matrices were developed and used to estimate remnant-mining risk and finally to quantify the decision on which of the three remnant blocks could be extracted at the lowest possible geo-mechanical risk. Il est courant dans les mines aurifères sud-africaines d’extraire des blocs de terrain isolés qui possèdent des niveaux élevés de contraintes et/ou sismicité. Les régions aurifères de Klerksdorp sont dominées par des blocs de terrain isolés qui sont séparés du gisement principal et qui sont retenus par des structures géologiques non continues, à parallèle de pendage et direction, et complexes. Il n’existe pas de méthodes quantifiables pour évaluer le risque associé à l’extraction de ce genre et autres genres de résidus. Une observation de cas, celle d’une mine d’or qui avait l’intention d’extraire trois blocs de résidus qui se trouvaient dans un grand système complexe de faille, est utilisée pour illustrer le processus décisionnel basé sur une combinaison d’observations souterraines, et de techniques numériques et sismiques. Des matrices simples d’estimation de risque furent développées et utilisées pour estimer le risque lié à l’extraction des résidus et finalement pour quantifier la décision sur lequel des trois blocs de résidus pouvait être exploité au moindre risque géo-mécanique. Die Extraktion isolierter Gesteinsblöcke mit erhöhtem Spannugsniveau oder Seismizität ist in südafrikanischen Goldminen üblich. Isolierte Gesteinsblöcke, die von der Haupterzader getrennt und durch komplexe, parallele abfallende und horizontale nicht persistent geologische Strukturen gebunden sind, beherrschen das Klerksdorp Goldfeld. Es gibt keine quantifizierbare Methoden die das Risiko welches mit dem Abbau dieser und anderer Klassen verbunden ist beschreiben. Eine Fallstudie einer Goldmine, welche die Extraktion von drei in einem großem komplexen Verwerfungssystem eingelagerten Einschlußblöcken plante, wird verwendet um den Entscheidungsprozeß zu illustrieren, der auf einer Kombination von Untertag Beobachtungen und numerischen und seismischen Techniken basiert. Einfache Gefahreinschätzungsmatrizen wurden entwickelt und angewendet um das Abbaurestrisiko abzuschätzen und letztendlich die Entscheidung zu quantifizieren, welcher der drei Einschlußblöcke unter dem niedrigst möglichen geo-mechanischen Risiko extrahiert werden konnte .

Jan 1, 2003

In the minerals industry allocating capital for setting up a new project or for upgrading an existing facility usually requires that a compromise be found between the initial cost of equipment, its operating performance and on-going operating costs. To maximise the return on the investment usually requires that various possible combinations and layouts of equipment be assessed. This task is both difficult and time consuming. Computer simulation can be used as a means of determining the expected operating performance of a range of alternate equipment configurations. Simulation is a particularly important technique for analysis as it is one of the few approaches that allows the analyst to take into account the variability inherent in a mining process. While computer simulation is a well established technique its use, until recent years, has been limited to large organisations with access to substantial computing facilities. However, with the current availability of low cost computing platforms combined with easily understood animated displays, simulation is now becoming more widely used across the industry.

Jan 1, 1990

By H. B. Arntzen, P. O. Grøntvedt, T. Lindstad, R. J. Ishak, M. Syvertsen

Better utilisation of electric power and coke is vital in reducing production costs and CO2-emissions in production of ferromanganese. All FeMn smelting operations consume 10 to 30 % more carbon than the carbon needed to reduce MnO and FeO to metal and the carbon contained in the alloy. Potassium which re-circulates and builds up in the furnace has been shown to be the main culprit causing both excessive carbon consumption, by catalysing the Boudouard reaction, and increased electric power consumption. The reaction between CO2 and ordinary metallurgical coke or coke impregnated with potassium has been studied at temperatures from 800 to 1100°C in a thermobalance apparatus. Ordinary coke did not react to any great extent at temperatures up to 1000°C, whereas the addition of potassium (2-10 %) resulted in a huge increase in reaction rates. The ultimate goal is to fit the results into a reaction rate model containing the equilibrium constant for the solid-gas heterogeneous reaction between CO2 and a free active site on the carbon reactant producing CO and adsorbed oxygen (an occupied site). The model includes the partial pressures of CO and CO2, a reaction rate constant that is a function of both the total number of reaction sites of carbon, and the potassium content. The potassium dependency is taken care of by introducing activity coefficients for the carbon sites. As the first step towards such a model, a regression line for the Boudouard reaction rate has been established.

Jan 1, 2004

By S. McPhail, D. Richardson, G. J. Simandl, C. Akam, S. Paradis, M. Yakimoski, A. Teucher, Y. Cui, F. Ferri

Historically, extracting dissolved solids from formation water was economically motivated. Today, main drivers are environmental benefits and regulations, as large volumes of water needed for hydraulic fracturing require treatment before reuse or disposal. The concentration of dissolved solids in flowback water increases with each use and may require treatment prior to disposal. Element recovery from produced water is not profitable unless market conditions are favourable, recoverable elements are abundant, and economical recovery methods are established. Sale of recovered materials could offset recycling and disposal costs. This paper describes markets for Cl, Na, Ca, K, Sr, Mg, Br, Ba, I, B, and Li, and their concentrations in produced water from oil and gas wells in British Columbia. It recommends revising sampling protocol for produced water.

Jan 1, 2018

By Michel Fontaine, Bruno St-Cyr

"The mission of the CENTRE DE RECHERCHE INDUSTRIELLE DU QUEBEC (CRIQ) is to stimulate economic development by guiding businesses in their pursuit of innovation.With a comprehensive approach to their needs, CRIQ provides businesses with expertise based on the most recent developments and insights in the fields of:Research and Development ServicesAutomation and production processesDevelopment of industrial equipmentEnvironmental biotechnologiesTesting and Product Qualification Services Industrial and Technological Information ServicesConsultancy and competitive intelligence servicesIndustrial information bankStandardization ServicesElaboration of standards and product certificationSystems registrationEXPERTISE COMPETENCE, INNOVATIONSince its founding in 1969, CRIQ has been involved in over 100,000 projects. The results of its research and development services have enabled it to build over one hundred pieces of equipment, almost all still in operation today. CRIQ has been and remains the driving force of innovation and expertise on the industrial scene, offering highly competitive solutions to a clientele from numerous industrial sectors.CRIQ became a crown corporation operating on a commercial basis on June 30, 1997. This change in its corporate structure has enabled it to put a marked emphasis on trade and implement an array of new operational practices.The formation of marketing companies with private partners, the opening up to corporate business and international markets, the new directions for internal research and the strengthening of its marketing component are among the activities CRIQ has initiated over the last fiscal year to finally reach its cruising speed."

Jan 1, 2000

By E. L. Burwell

Preliminary results of an in situ oil shale retorting experiment conducted by the Bureau of Mines in a shallow bed of Green River oil shale at Rock Springs, Sweetwater County, Wyo., are described. Eleven wells were drilled into a 20-ft-thick section of the shale lying between 68 and 88 It deep, and attempts were made to connect the wells through the shale with a fracture system created by application of high-voltage electricity (electro-linking), hydraulic fracturing, and explosive fracturing. Ignition of the shale through the central well was easily achieved with a propane burner, and shale oil began to collect in three wells within 3 hours. Propane injection was discontinued after 7 days, and combustion continues, although attempts to control the direction of the combustion front have been unsuccessful. Production rates as high as 4 ½ barrels of nil per day have been recorded, but too little is known about underground conditions to permit an estimate of recovery efficiency at this time.

Jan 1, 1969

By D. Denton, M. Stickney, R. Langston

The National Institute for Occupational Safety and Health and the Stillwater Mining Company worked cooperatively with the Montana Bureau of Mines and Geology to develop a system that would collect seismic data at the Stillwater and East Boulder mines. The purpose was to obtain baseline information on the magnitude and location of mining-induced seismicity to determine if the mines needed multi-channel in-mine monitoring systems. Seismic data recorded at field sites near the mines are being telemetered via FM radio through a series of repeaters to a central recording site where the seismic signals are digitized using an Earthworm data acquisition system. The Earthworm system performs several data analysis tasks in near-real time and places raw seismic data, preliminary hypocenter locations, and magnitudes on a Website within 5 min of a seismic event. Such rapid access to seismic data allows personnel at the Stillwater Mine, Spokane Research Laboratory, and Earthquake Studies Office to evaluate seismic events quickly and respond in ways that may improve the safety of mine personnel underground. Installation of the system also broadened earthquake coverage to south-central Montana, a region previously not covered by the seismograph network.

By Paul Eger

The use of wetlands to treat mine drainage has become increasingly common, particularly as more information is available on their operation and construction. However, the lifetime of each system is still, at best, an estimate. Treatment lifetime depends on the types of processes that provide the majority of the metal removal. Anaerobic systems (vertical flow systems) rely primarily on sulfate reducing bacteria, which reduce sulfate to sulfide and generate alkalinity. Metals can be precipitated as sulfides, and acidity is neutralized. These systems can remove over 90% of the metals and increase pH from around 4 to over 7. The bacteria will remain active as long as the system remains anaerobic and contains an adequate supply of sulfate and small chain organics. Although estimates of lifetime made on the total carbon in the system suggest that lifetime should exceed 20 years, data from field and laboratory studies show that the rate of sulfate reaction decreases with time, and that after several years rates decreased substantially. To maintain acceptable treatment, either additional organic material must be added or the total metal and acid load to the system would need to be reduced substantially. Aerobic systems (overland flow wetlands) can effectively remove metals from neutral mine drainage by reactions with organic material in the substrate. Over 90% of the copper and nickel have been removed in aerobic systems treating mine drainage in Minnesota. The primary removal processes in these systems include adsorption, ion exchange and complexation, which are finite; removal will cease unless new removal sites are generated. Two wetlands built in Minnesota have been successfully treating mine drainage for 12 years. At one of the wetlands, the annual production of new removal sites has been estimated to be equal to the annual metal input, and, as a result, metal removal should theoretically continue indefinitely.

Jan 1, 2005

By John D. Watson

The results of extensive field tests of a new and powerful method of hard rock excavation are presented in this report.* The method, known by the acronym REAM (Rapid Excavation and Mining), employs high velocity, smooth bore cannons to efficiently deliver energy to the rock and has been demonstrated for underground tunneling, drilling, surface benching, scaling, and secondary breakage in hard granitic rock at the Hope Valley Mine test site in California. Solid projectiles made from inexpensive materials such as concrete or steel, and weighing from 8 to 12 pounds, are launched by conventional high speed cannons and impact the rock at velocities of 5000 feet per second--an impact energy of about 4 million foot pounds (Figure 1). The energy applied at peak pressures of nearly 2 million psi over a period of tens of microseconds breaks down the rock by a complex mechanism of crushing, spalling, and initiation and propagation of fractures produced by the interaction of successive impacts and free surfaces. The main objective of the tests during 1973 was a demonstration of controllability of the underground operation of a silenced cannon. To accomplish this objective a 90-mm cannon

Jan 1, 1974

By Doss H. White

Alabama's non fuel mineral industry produced $560.6 million of mineral commodities in 1990. This was an increase of $99 million over the 1989 value and a new State record, a record achieved despite the slowdown in the national economy. This was the first year that Alabama's mineral value exceeded one-half of 1 billion dollars. The value of stone and cement, the two leading mineral commodities in terms of sales, increased $71 million over that reported for 1989 and was the primary reason for the new mineral value record. The State ranked 21st among the 50 States in total mineral value and contributed 1.68% of the total U.S. mineral value of $33.3 billion.

Jan 1, 1992

Analysis of rock discontinuities, collected using a scanline method, has been undertaken at the Iron Duke open cut mine, on the southern margin of the Middleback Range in the Gawler Craton, South Australia. The iron mineralisation, which is a product of supergene enrichment of carbonate sediments, is located on the W (western) limb of a gently N plunging D2 macrosyncline. Mesofolds plunge shallowly to the NE or steeply to SE, suggesting two shortening events, of which the second produced significant macrofolds. Discontinuities include:faults and shears which display variable orientations, mainly striking WNW dipping steeply N; mesofractures or joints maintaining a well constrained orientation, dipping steeply S, subvertical striking E-W; and bedding surfaces which are folded about a gently N plunging axis. Through this example of the regional control exerted on local discontinuities, it is clear that discontinuities are not randomly distributed as often assumed in purely statistical approaches. Commonly for rocks of any age there is a distinct discontinuity pattern, reflecting the geological deformation history. If the controls exerted on local rock discontinuities can be determined and assigned a number related to their significance, the way forward is available to develop a site specifc knowledge base that can make realistic predictions for any position in a given rock mass. Such a procedure would involve assessment of the regional geology, linked to scanned discontinuities either via manual or automatic means. Recent advances in automatic scanning rock faces (eg by the I-SiTE Laser Radar) to determine discontinuities distributions, enable the rapid calculation of rock characteristics. This is a significant advance in rock engineering, providing a method of safe and quick collection of data. However it creates problems in the presence of an increase in the geotechnical data available, which should be assessed in the context of the regional geology. Although techniques are underway to analyse post-blast discontinuities, the next signifant potential advance in this area could be the integration of a knowledge based system to assess discontinuities ahead of mining, incorporating regional assessment and human intuition.

Jan 1, 2000

By I Sherrell, R Jain, P Jansson

With the depleting iron reserves and difficult market conditions, precision in separation efficiency is of utmost importance. Classical local control options are predominant in the industry, but their inability to adjust to resolve application problems of interest has furthered the need of developing and implementing continuous control methodologies.This paper highlights the recent development in control of Outotec SLon® vertically pulsating high gradient magnetic separator (VPHGMS) including programmable logic controllers (PLC) coupled with distributed control system (DCS), on-site human–machine interface (HMI) control panel, advanced process control, continuous online sampling using Courier® 8 and additional modernisation packages including level control and cooling monitoring. These modern control options result in improved efficiencies, promote safer operation and at the same time reduce operational manpower needs.CITATION:Jain, R, Sherrell, I and Jansson, P, 2017. Automation for efficient separation with the Outotec SLon® vertically pulsating high gradient magnetic separator, in Proceedings Iron Ore 2017, pp 211–214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By B. A. Rogers

IN addition to the usual methods of manufacturing steel, a number of special processes have been the subject of considerable experimentation-and use in manufacturing practice. A number of these methods have been of a type in which a rapid refining action has been secured through the intimate mixture of fluid slag with fluid metal. The persistence with which more rapid methods are sought is indicated by the current interest in the Aston' method for producing wrought iron and in the Perrin2 process for dephosphorizing and deoxidizing steel. In the Perrin process, in particular, the mixing action is extremely vigorous and the reactions proceed with surprising speed.

Jan 1, 1936

By C. B. DUTTON, W. F. RITTMAN, E. W. Dean, M. S. HOWARD

NOMENCLATURE USED IN THIS REPORT. In this report the ending ene has been used throughout, except in the bibliography and in quotations from the writings of previous investigators, for all aromatic hydrocarbons, as, for instance, benzene, toluene, xylene. The ending ol, though largely used in technical description, is not correctly applicable to these hydrocarbons, and should be used to designate the impure mixtures of commerce, as distinguished from pure chemical compounds. PRESENT STATUS OF PETROLEUM-REFINING INDUSTRY. Although petroleum is widely distributed, being found in many parts of the world, and although information as to its occurrence and general characteristics seems to have existed from vcry early times, our knowledge of the chemical nature of this substance has been acquired largely within the past 40 years. Within this period a voluminous literature has accumulated, which records work as painstaking as has ever been undertaken in the whole field of chemistry, such as that of C. M. Warren, F. H. Storer, S. P. Sadtler, S. F. Peckham, and C. F. Mabery. Despite this fact, the commercial method of treating crude petroleum for the purpose of procuring marketable products is, in the main, essentially empirical. Much knowledge has been acquired as to methods of separating from crude petroleum such products as are desirable commercially, but little has been done to attain the maximum recovery of such products.

Jan 1, 1916

By Joseph L. Young, Richard A. Bohling

To keep Homestake's Bulldog Mountain silver and lead mining and milling operation in southwestern Colorado workable, natural ground water and decant water from the mine's sand backfilling operation must be continually pumped from the workings. Left untreated, this water exceeds maximum allowable levels for various contaminants that may be discharged to the environment. To comply with regulations, a National Pollutant Discharge Elimination System (NPDES) permit was obtained and a mine water treatment plant for heavy metals removal was constructed in 1977. Due to equipment capacity and operational problems, and the lack of on-site technical personnel and analytic equipment, the first water treatment plant could not consistently meet permit limits. In 1979, Homestake entered into a consent decree with EPA and the Colorado Department of Health, calling for the construction of a water treatment facility to meet NPDES permit limits. Initial construction began in the spring of 1980 and the plant now produces effluent acceptable for discharge.

Jan 12, 1981

By Joan Stoupa

The expansion of the West Point wastewater treatment plant located in Seattle, Washington, will require a permanent tieback retaining wall to enlarge the plant site for the new treatment plant facili­ties. The retaining wall will extend approximately 3,000 feet along the property boundary between the treatment plant and the neighboring Discovery Park. Wall heights will range from 35 to as high as 65 feet. The purpose of the retaining wall is to provide a more uniform grade on the plant site and to resist lateral pressures exerted by the upslope, unstable hillside. During preliminary design of the retaining wall, various wall systems were evaluated based on assumed subsurface soil conditions. Results of preliminary studies indicated that expected subsurface conditions and wall heights made a permanent tieback retaining wall feasible. However, uncertain loads on the wall and the capacity of anchors in the native soils were significant. As a result, a detailed geotechnical program was conducted. The scope of the program included conventional drilling, sampling, analyses, and a field test program to determine site-specific anchor capacities. This paper describes the anchor test program and results.

Jan 1, 1990

Longwall mining has existed in Utah for more than half a century. Much of this mining occurred at depths of cover that significantly exceed those encountered by most other U.S. longwall operations. Deep cover causes high ground stress, which can combine with geology to create a coal burst hazard. Nearly every longwall mine operating within the Utah’s Book Cliffs coalfield has been affected by coal bursts.

Jan 7, 2020

By Dean E. Matthews

The concept of a pile for construction is credited to a Neolithic tribe called the "Swiss Lake Dwellers" who lived in what is now Switzerland about 6,000 years ago. They used piling, not for supporting heavy loads as we do today, but for elevation to protect themselves from wildlife. The Romans often used piles, and built many structures, including buildings, homes, bridges, roads and viaducts on piling. The Romans built the first bridge across the Tiber River in Rome on timber piles in B.C. 1620. Homes in the cities of Venice and Ravenna were built on piles from B.C. 100 to A.D. 400. The Romans also built the first bridge across the Thames River in London in A.D. 60 on timber piling.

Jan 1, 2003

By R. C. FLEMING

MINING rock asphalt for use as a paving material is an industry which has grown with the spread of the good roads movement. "Mineral Industry During 1930" reports asphaltic pavements constructed, including maintenance and repair but excluding pavement constructed with road-oil, cut-back or emulsified asphalt, as grown from 23 million square yards in 1911 to a high of 144 million in 1927. In 1930 the same source reports 106 million square yards of such paving laid and, in that year, 664,871 tons of native rock asphalt were so utilized. Many states contain rock asphalt deposits of greater or less importance but in only a few places are the de¬posits being mined commercially. In the year cited Ken¬tucky produced 305,024 tons of bituminous sandstone, Texas 270,138 tons, mostly bituminous limestone, while Alabama, Oklahoma, California and Utah produced 89,709 tons of bituminous rock for road construction. In addition Utah produced 37,906 tons of the purer asphaltic products, gilsonite, wurtzilite and ozokerite, for other uses. Speaking generally, the rock asphalt is a sandstone or limestone naturally impregnated with asphalt to an extent that makes it an ideal road surfacing material without mixing or treatment other than crushing. The asphalt content of the commercial product runs 8 to 12 per cent.

Jan 1, 1933

The ore, as sent to the sulphide mill, is a mixture, in varying proportions, of oxidized ore from above the 450-ft. level and sulphide ore from above and below (to date mainly from above) that level. The oxidized ore consists essentially of quartz, with varying amounts of kaolin and clayey material which passes into the slime and, in excess, creates a serious problem in settling. Pyrite may be present in small amounts. The gold is free and extremely fine.The ore, classed as sulphide, consists of pyritic material in a quartz gangue. The sulphides have been exposed to weathering, leaching by descending solutions and attack by ascending gases and actual burning. The alteration products occur in widely varying proportions and this variation adds to the difficulties in settling and control of grinding and flotation.Copper Minerals.-Chalcopyrite is the principal copperbearing mineral with smaller and varying amounts of covellite, which is sometimes associated with chalcocite, both these minerals being apparently of secondary origin.Examination of tailing by Dr. Stillwell has revealed all stages between clean chalcopyrite, chalcopyrite tinged with covellite, covellite with residual cores of chalcopyrite and clean covellite.The chalcopyrite is free floating, very few particles of clean chalcopyrite being observed in the tailing from granular flotation. The chief tailing loss is probably as chalcopyrite occurring as small inclusions in pyrite...

Jan 1, 1939