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By Robert B. Parsons

"Exploration and development of mineral resources in developing countries by Canadian-based multinational mining companies is becoming increasingly common. One problem being encountered is that the objectives of the governments of developing countries can differ from those of developed countries. These objectives are not always consistent with maximizing returns from the projects, which can create conflicts between the mining company's responsibility to its shareholders and the desire to be a good corporate citizen. This article discusses how a mining tax regime can be designed to make the social goals of a government consistent with the economic goals of the company.IntroductionAt the recent International Seminar on Mining Taxation organized by CIM and the United Nations there was considerable discussion about the role of international mining companies operating in developing countries. Not surprisingly, given the diversity of backgrounds of individuals attending the Seminar, there were different opinions about what this role should be.Government PositionRepresentatives of governments pointed out the strong desires of their countries for technology, high-level technical training of their workforce, increased employment, and development of social infrastructure. They pointed out that, to a large extent, these objectives could be more efficiently met by mining companies operating in the country than by the governments themselves. For example, a multinational mining company (""MMC"") would have extensive knowledge of the various technologies available, and would have performed a detailed evaluation of the mineral resources before choosing the most cost-efficient technology for that project. They would, therefore be in an ideal position to assist the country in importing and developing such technology. Similarly, the company could provide opportunities for hands-on training, both at the technical and managerial levels, which would otherwise be unavailable to the government."

Jan 1, 1991

By Tuncel M. Yegulalp

The objective of this study was to categorize mining operations in the stone, and sand and gravel industries into areas of similar ground control functions and define initial factors affecting operational safety in each area, by means of utilizing publicly available data, telephone interviews and on site observations. The findings and recommendations presented in this report are based on the information collected during the two phases of the project. They also contain, in part, the collective qualitative opinion of the operators with respect to government rules and regulations on ground control safety and the implementation of these rules and regulations by government inspectors.

Jan 1, 1981

By L. Jeffrey

The Waterberg Coalfield has vast potential to become a significantmining and industrial centre in South Africa. Its future developmenthinges on a number of critical decisions that must be made jointly by government, power utilities and industry, and on some technical and economic challenges that must initially be overcome. Sufficient water is the primary key to enabling exploitation, together with an adequate market for the large volumes of low-grade coal. As the most likely consumer of this coal will be either a power station or a petrochemical complex, the need for additional energy will be a driving force in the development of this coalfield. Conventional mining methods can exploit the shallow coal resources in both the Grootegeluk and the Vryheid formations, but alternative technologies such as coalbed methane extraction and underground coal gasification are the only currently known technologies that may be able to exploit the deep Grootegeluk Formation resources. However, extensive research is still required into these procedures, particularly with respect to the Waterberg coals. Transport infrastructure to the region is currently not sufficiently well developed to support large-scale exploitation of the region?s coal resources. In particular, the railway line would have to be extensively upgraded to allow the increased export of coal. Alternative transport methods such as pipelines would also have to be pursued to serve a large Sasol-type petrochemical complex or coal gas extraction. The road network would also require improvement, as only the roads between the main commercial centres are currently tarred. Dr Con Fauconnier, Kumba CEO, concluded his presentation to the Investing in African Mining Conference 2004 with the words: Again, it?s all about infrastructure? when it?s there, it enables the development of bulk mining projects which attract the resultant economic benefits for the region and country as a whole. These words aptly sum up one of the stumbling blocks to the future development of the Waterberg Coalfield.

Jan 1, 2005

By Madan Kumar Annam, Hari Krishna Y

"Basement construction is one of the challenging geotechnical concerns in the urban environment. Several types of retention systems are practiced to support the earth which is suitable for restricted access, rapid mobilization, fast excavation and cost-effective designs. A thorough understanding of geotechnical engineering as well as the structural mechanics is important for the earth retention systems. This paper discusses a project with various types of foundation solutions including monitoring of deflections during excavation stage of a retention system.A multi storeyed residential building (3B+Stilt+18F) in Chennai having structure foot print area of 1500 m2 has to be constructed on large diameter pile foundations and also to support the proposed basement excavation. Ground water table was encountered at about 6m below the existing ground level (EGL). In order to support heavy structural loads, large diameter bored cast-in-situ piles were chosen and installed. Further, complete retention system was economically designed and built, which includes installation of Contiguous Bored Piles (CBP) in combination of vertical grout columns behind CBP wall to seal the gap between the CB Piles, installation of inclined ground anchors, construction of capping beam, stressing and locking of installed ground anchors. A detailed monitoring program was in place and continuous monitoring of wall deflections is being measured at the time of publishing this paper. This paper describes the design and construction aspects adopted for foundation and retention system including the monitoring results during excavation stage of the project.INTRODUCTIONIn general, stage wise open excavation will be opted for basement construction where plenty of space is available. Due to urbanization and restricted space, open excavation became a difficult task nowadays. To overcome this problem, suitable retention system need to be selected to retain the soil mass. Selection of suitable retention system for multi-level basement excavation is a great challenge in geotechnical industry, especially when the proposed site is located within the minimum set back distance from the existing structures. This in turn calls for the advanced and innovative methods of retention system.Several earth retention systems such as Diaphragm Walls, Secant Pile Walls, CBP system, Soldier Pile Walls, Sheet Piles, Deep Soil Mixing (block walls) etc. with or without inclined ground anchors are being practiced worldwide. Considering the advantages and disadvantages of the available retention systems in practice locally and keeping in view of present site conditions, the developer has chosen CBP system with inclined ground anchors so that all foundation related works of the project will be handled in a single package. The main advantage of such packaged solution will ease the coordination between design consultants and foundation contractor resulting in faster construction of foundation works which in turn reflect savings in time and cost."

Jan 1, 2015

By J. J. Forbes

The activities of the Bureau of Mines include the development and testing of self-contained oxygen breathing apparatus and other devices for respiratory protection, the development and tasting of devices for detecting dangerous or noxious mine atmospheres, and the training of men in the mineral industries in the use and care of this equipment to enable them to render effective service in mine rescue and recovery operations following mine fires and explosions, or under other conditions where irrespirable gases may be found in mines or mining plants. The first use of self-contained oxygen breathing apparatus for com- bating mine fires and explosions in the United States dates back about 30 years. Previous to that time, exploration for any distance ahead of fresh air was virtually impossible without great risk to life; moreover, the men called upon to render service at mine disasters were not well-versed in the properties and physiological effects of gases likely to be encountered. It was also impossible to work ahead of fresh air to restore ventilation, and if many stoppings were blown out by an explosion, air had to be introduced into whole areas or sections at once without knowledge of the conditions ahead; moving an explosive mixture of methane and air over live fire had to

Jan 1, 1938

By Raymond M. Stateham

Infrared and displacement studies were made of an unsupported roof in Kaiser Steel Corp.'s York Canyon coal mine, Raton, N. Mex. Monitoring of the roof continued until the roof over the area was caved. Loose slabs in the roof, about 6 inches thick, were detected by means of associated thermal anomalies, using remote-sensing infrared instruments. Displacement measurements taken during the study indicate that roof movement was cyclic in nature; the cycles appear to have been related to the mine work cycle (work days to idle days).

Jan 1, 1974

By R. G. Turner, M. G. Hubbard, A. E. Dukler

Gas phase hydrocarbons produced from underground reservoirs will, in many instances, have liquid phase material associated with them, the presence of which can affect the flowing characteristics of the well. Liquids can come from condensation of hydrocarbon gas (condensate) or from interstitial water in the reservoir matrix. In either case, the higher density liquid phase, being essentially discontinuous, must be transported to the surface by the gas. In the event the gas phase does not provide sufficient transport energy to lift the liquids out of the well, the liquids will accumulate in the wellbore. The accumulation of the liquid will impose an additional back pressure on the formation that can significantly affect the production capacity of the well. In low pressure wells the liquid may completely kill the well; and in the higher pressure wells there can occur a variable degree of slugging or churning of the liquids, which can affect calculations used in routine well tests. Specifically, the calculated bottom-hole pressures used in multirate backpressure tests will be erroneous if the well is not removing liquids on a continuous basis, and gas:liquid ratios observed during such a test may not be correct. Several authors1,3,8,14 have suggested methods to determine if the flow rate of a well is sufficient to remove liquid phase material. Vitter14 and Duggan' proposed that wellhead velocities observed in the field would be adequate for keeping wells unloaded. Jones8 and Dukler3 presented analytical treatments resulting in equations for calculating, from physical properties, the minimum necessary flow rate. An analysis of these studies indicates the existence of two proposed physical models for the removal of gas well liquids: (1) liquid film movement along the walls of the pipe and (2) liquid droplets entrained in the high velocity gas core. Although there probably is a continuous exchange of liquid between the gas core and the film, they will be treated separately for the purposes of this study. The development and comparison of these separate models with experimental data will permit the determination of which, if either, is the controlling mechanism for the removal of liquids from gas wells. The Continuous Film Model Liquid phase accumulation on the walls of a conduit during two-phase gas/liquid flow is inevitable due to the impingement of entrained liquid drops and the condensation of vapors. The movement of the liquid on the wall is therefore of interest in the analysis of liquid removal from gas wells. If the annular liquid film must be moved upward along the walls in order to keep a gas well from loading up, then the minimum gas flow rate necessary to accomplish this is of primary interest. The analysis technique used follows Dukler2 and Hewitt5 and involves describing the profile of the velocity of a liquid film moving upward on the inside of a tube. The minimum rate of gas flow required to move the film upward is then calculated.

Jan 1, 1970

By Jerry E. Olson

In 1984, the U.S. Bureau of Mines conducted a mineral survey of the Pahute Peak Wilderness Study Area (WSA) (NV-020-621), which covers 57,529 acres in Humboldt County, NV. About 90 percent of the WSA is underlain by Tertiary volcanic and shallow intrusive rocks. Of the remainder, metasedimentary rocks of unknown age are in contact with Cretaceous intrusive rocks in the northwest corner of the WSA. The entire WSA is within an upthrown fault block of the Basin and Range physiographic province. Portions of the WSA, especially south of Pahute Peak (Big Mountain), may be part of an eroded caldera structure. No mines or evidence of major exploration were identified within the WSA. Workings in Copper Canyon, claim blocks along the northwest boundary, and zones of anomalous character as defined by the Bureau of Land Management were examined. No mineral resources were identified, but sample results indicate three significantly mineralized sites, one with indications for zinc skarns in Copppr Canyon, another favorable for precious metals 2 miles south of Copper Canyon, and another area near the northwest boundary with geologic conditions characteristic of molybdenum deposits. Further investigation of these sites is warranted. Petrified wood is present in small amounts near the west central range front.

Jan 1, 1986

By Nicol S. K, Swanson A. R

The poor flotation response of many coals has in the past been attributed to such factors as differences in rank, differences in degree of oxidation, differences in petrographic composition, or slime coatings. The present work shows that while all these factors undoubtedly influence flotation, the size distribution of the feed may override these. Evidence is presented which shows how this factor can lead to substantial losses of coarse coal (>250 µm)from a coal which would normally be considered amenable to flotation. Reasons for this loss of flotation response are suggested together with means of overcoming the problem.

Jan 1, 1978

By Art Carino

"The McClean Lake operation is located in the Eastern Shore of the Athabasca Basin in northern Saskatchewan some 700-air kilometers north of Saskatoon. It is operated by Cogema Resources Inc., the major share holder of the joint venture consisting of Cogema Resources Inc., Denison Mines Limited and OURD, a consortium of Japanese utilities.The JEB mill is the first uranium mill to be constructed and licensed in North America within the last 15 years. The mill uses conventional uranium unit process but employs innovative techniques unique to the JEB mill.This paper presents brief descriptions of the various unit processes, the innovations and the commissioning strategies developed to achieve the designed production capacity in the shortest possible time.INTRODUCTIONThe McClean Lake ore body was discovered in 1979, followed by the discovery of the JEB ore body in 1982. From 1985 to 1990, a cluster of deposits named Sue A, Sue B and Sue C were discovered. Environmental Impact Assessment (EIS) of the McClean Lake project began in 1990 under a joint federal-provincial process. Following the public hearings in 1993, the governments gave approval to proceed with the construction of the project, subject to fulfilling licensing requirements.The McClean Lake ores are located in the uranium-rich geological region of Saskatchewan known as the Athabasca Basin, 700 air kilometers north of Saskatoon. The JEB mill is located near the mined out JEB open pit that is now used as the tailing depository.The approved mill has a production capacity of 6,000,000 pounds of U3O8 annually and is capable and licensed to process JEB, Sue A, Sue B, Sue C, McClean Lake, and Midwest Lake deposits. Although the EIS has been approved, Mining of the Midwest Lake deposit has not been approved at this time."

Jan 1, 2001

By Luis Martín Tejada

Para la evaluación de la estabilidad de taludes en minería superficial se utilizan diferentes métodos de modelamiento y planeamiento como el de simulación numérica. En ese sentido, el presente texto describe el método de tensión-deformación, cuyo base se encuentra en el método numérico de elementos finitos, y así localizar la probable superficie de ruptura. También se describe los mecanismos de ruptura en taludes altos, el cálculo del FS y algunas características del programa de elementos finitos PLAXIS.

Sep 9, 2007

By William R. Wessels

This report describes a field survey and laboratory investigation into the causes of failure of resiliently clad screen decks applied to coal preparation plants. Blinding of screen deck perforations and delamination of the resilient cladding are studied and mechanisms responsible for these failure modes are hypothesized. A laboratory test program to simulate the mechanisms was begun and abandoned when it became apparent that meaningful test results would require a substantially redirected effort. No meaningful test data was obtained from the laboratory simulation.

Jan 1, 1982

By Erich J. Jacob

In the past 15 years the enforced improvement of the public traffic systems caused a boom in urban tunnel construction. In 1961 the City of Paris started to build the Express-Metro. Of the 47 km long double-track line crossing the city center, nearly 45 km are in operation since 1971. Still missing is here only an about 2.6 km long connecting stretch, which is under construction now. From 1963 to 1969 the 21.8 km long Victoria Line was built in London as extension of the existing network,. A little later, in the years 1965 to 1973, the City of Hamburg supplemented its subway network by the construction of a 16.8 km long line between the Boroughs of Billstedt and Stellingen. Also in 1965 the City o Munich started to build a subway system of 54 km f length. Thereof a stretch of 16.2 km could be taken into operation in 1972 shortly before the Olympic Games. These are only some of the better known projectsas examples of the activities in European cities. In nearly all cities with more than about ½ million inhabitants subsurface traffic lines were begun or supplemented. Furthermore, numerous undercuts or other subsurface structures were built. The Ij Tunnel in Amsterdam and the new Elbe Tunnel in Hamburg may be mentioned, both structures finding international attention.

Jan 1, 1976

By Peter Barker, Terry Jones

"The Kelsey Centrifugal Jig (KCJ) utilizes the application of centrifugal force (and the resultant enhanced gravitational field) to conventional jigging technology principles to successfully and efficiently process materials where the valuable constituent particulates are very fine and/or where there is a small specific gravity differential between these and the gangue minerals.The KCJ is applicable to a broad range of fine mineral recovery duties, with current installations in the mineral sands, tin, tantalum, gold and nickel industries. Other areas of application are being developed with mineral commodities including tungsten, base metals, iron ore, chromite and apatite/feldspar.Information on the principles of operation of the KCJ, typical performance figures in a number of application areas, comparison to centrifugal concentrators, key elements for a successful KCJ operation and recent developments with the KCJ are presented in this paper to demonstrate the capabilities of the KCJ.INTRODUCTIONAfter a number of years of development by inventor Chris Kelsey, the first commercial KCJ unit was installed at the Renison Bell tin mine in Tasmania, Australia, in 1992. The subsequent decade saw the installation of further KCJ units in applications including tin, tantalum and mineral sands.Development and improvement in KCJ hardware continued and culminated in the introduction of the high-capacity Model J1800 KCJ and standard features such as an automatic screen cleaning system. This opened up further markets and resulted in Model J1800 KCJ installations in the gold and nickel industries, as well as further KCJ installations in the mineral sands and tin industries. In recent years, work has continued on application of the KCJ to many other duties in industries including tungsten, base metals, iron ore, chromite, apatite/feldspar, etc."

Jan 1, 2007

By Gordon Chen

The Block 37 Chicago Transit Authority (CTA) Tunnel Construction Project was originally designed by STV to connect Blue Line subway in North Dearborn Street and Red Line subway in State Street in the downtown Chicago Area. The project was proposed using tunnel mining techniques combined with steel pipe jacking and fiber glass rebar soil reinforcement. Weidlinger Associates, Inc. (WAI) and Kiewit Construction Company proposed an alternate design using open cut construction technology. WAI designed a complex temporary excavation support system using Soldier Pile Tremie Concrete (SPTC) walls and Soldier Pile Lagging walls supported by cross lot/corner bracing elements. Below the top of the existing tunnel, a top-down construction technique was utilized. A steel temporary traffic decking system at top of the excavation site served as the daily street traffic function as well as the first level of bracing for the support of excavation. The project encountered great challenges of soft clay conditions in downtown Chicago, numerous existing utilities in the excavation site and the requirements of protection for a number of historical buildings nearby as well as the protection of the city streets. The construction was successfully completed at both State Street/Washington Street and Dearborn Street/Randolph Street. The monitoring system showed that ground movement and adjacent building settlement was kept to a minimum during construction.

Jan 1, 2009

By G. Kim

The influence of bacterial growth phase on the flotation behavior of malachite has been investigated in a well-controlled Hallimond tube system. The microflotation tests were conducted for malachite (45?53 µm) using different amounts (bulk phase concentration=1×108?5×109 cells/mL) of Rhodococcus opacus (R. opacus) as a collector, which was grown at mid-exponential versus stationary phase, at a constant speed (340 rpm), pH (6), and malachite-bacteria interaction and flotation time (each 10 min). Hug differences between R. opacus cells in mid-exponential and stationary phase was observed from the results for electrophoretic mobility and flotation tests. Specifically, the isoelectric point of the cells in the stationary phase was lower than that in the mid-exponential phase, suggesting that the amount and distribution of surface functional groups onto cell surfaces are likely different. Additionally, the cells in stationary phase led to significant increase in the flotability compared to those in mid-exponential phase over the background bacterial concentration level of 1×108?5×109 cells/mL. Furthermore, the flotation efficiency tended to increase with increasing cell dosage for stationary phase cells while no distinct difference was observed for mid-exponential cells.

Feb 27, 2013

By R. Sankey, L. Gatty, F. Bizzozero, G. F. Shannon, F. Savaglio, L. McDonald

State mining regulations in Queensland stipulate that a mine be provided with an earth installed on surface and that all underground equipment that needs to be earthed should be connected via a copper conductor to this surface grounding point. The regulations further require that all exposed metal surfaces in underground substations be connected to an earth. In a study of earthing conditions at Mount Isa mine it was found that the physical anchoring of metal work at substations (with rockbolts and associated steel mesh) also provides an excellent electrical connection to the country rock. It was established that not only is the mine's earthing system grounded at numerous underground locations but also that such anchor points offer, in general, a path to ground with lower resistance than does the legally required grounding point on the surface. It is recommended that metalliferous mines should utilise a multiple-earth system and not a run earth connected to a single, above-ground earth point

May 1, 1991

By R J. Mills, B S. Sinclair, D A. Fergusson, A G. Goldstone

In 2005, Solid Energy New Zealand Limited obtained non-notified consent for the disposal of 1Mt of coal ash at the Rotowaro minesite, forming part of a coal supply agreement with the Huntly Power Station. The consenting of major mine site activities has historically required wide consultation and involves notification of the application.   The risk and cost associated with consultation can be significantly reduced via a non-notified process. A non-notified consenting process necessitates environmental effects to be shown to be æless than minorÆ, which requires the combination of robust science and a pragmatic approach to design, assessment of environmental effects, and consenting issues.   Key issues examined included consideration of how to practically operate a significant disposal project within the confines of an operating mine, minimising the costs, civil and geotechnical design and practical issues associated with traditional disposal. Environmental issues specifically related to the coal ash, led to a site specific performance driven approach to management rather than relying on conventional prescriptive approaches. Environmental issues of concern include the leaching of boron and aluminium from ash into groundwater and mine water management systems where both boron and aluminium can occur at elevated levels.   Coal ash exhibits unusual geochemical characteristics reflecting the primary coal composition and the combustion process. The dominant coal type combusted at the Huntly Power Station is derived from Rotowaro and the resulting ash is cementitious and has a high alkalinity. As a result the disposal design is based on the characteristics of the ash itself rather than the material into, or onto which the ash is disposed. Non-notified status was able to be achieved through consideration of these key characteristics of the ash, ensuring that the dimensions of the disposal site and each location was designed to minimise the flow of groundwater through the ash and demonstrating that the physical ash disposal effects are less than minor compared to the consented mining operation.

Jan 1, 2006

By R. L. Blake

The crystal structure of hematite, a-Fe203, has been refined as part of a continuing study of the behavior of phases in the Fe-O system during reduction and oxidation. Three-dimensional diffraction intensities were collected on two spherical single crystals of hematite with a semiautomated Buerger single-crystal diffractometer. The first crystal refined was a natural Elba hematite with minor impurities. The other, a synthetic crystal, was refined at the request of Mossbauer spectroscopy investigators concerned with impurities in the natural crystal. The structure has been refined with a least-squares program and the final structure for the natural crystal irradiated with CuKa-radiation gave a discrepancy factor (R) of 3.65 percent using 49 unrejected reflections of the 51 measured. For the synthetic crystal, using MoKa-radiation, the discrepancy factor converged to 2.8 percent using 95 unrejected reflections and was 3.3 percent for all 109 reflections. The structure model of Pauling and Hendricks has been confirmed with essentially no change in the iron coordinates and approximately a 5-percent change in the oxygen coordinates. Selected interatomic distances and angles were calculated as were anisotropic temperature factors.

Jan 1, 1970

By Dennis Ofiara

Several recent tunnel jobs have required special adaptations of hard rock TBMs. Some of the special job conditions are ?no blast? launch requirements, small shafts or launch pits, proximity to existing underground structures, and short tunnels where the TBM must be retrieved through the primary lining. This paper describes a few of these projects, and the machine adaptations that have made TBM excavation feasible.

Jan 1, 2008