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By Oliver Bowles

Whiting or Paris white is a fine-grained preparation of calcium carbonate having a wide variety of uses. Until recent years it was prepared almost exclusively from certain north European chalks. With the curtailment of imports of European chalk during the World War of 1914-18, however, finely ground limestone, of domestic origin was used more extensively to satisfy the American demand.

Jan 1, 1942

By James E. Parkes

The Silver Spring Transit Center is a new three-level transit center that will include bus loops for County, Metro and intercity buses, parking, and retail space. It replaces an existing bus station and connects to a busy metro rail station in downtown Silver Spring, Maryland. Significant site constraints in both plan and profile had to be dealt with in developing a design for support of the structure. Over 90 rock-socketed drilled shafts ranging in size from 3 to 7 foot in diameter were ultimately used to accommodate the limited space and large column loads, and to adapt to the variable rock surface at the site. Site access during design was limited due to the existing active bus station, so contract documents were adapted to include further explorations. Differences in anticipated and actual field conditions regarding the depth, quality, and variability of the rock had to be overcome in construction. Osterberg Load Cell testing during construction allowed for verification and optimization of the shaft design. Additional issues dealt with on this constrained site in an urban setting included construction staging issues, such as working around specialty contractors for tieback walls, blasting operations for rock excavation, productions issues for hard bedrock, as well as coordination issues with third parties, most notably the Washington Metro Area Transit Authority. Aspects of the foundation design and optimization, preparation of the contract documents to deal with the complicated nature of the project, and lessons learned from construction are also discussed.

Jan 1, 2011

By John W. Cahn, David A. Karlyn, Morris Cohen

The massive B(bcc) — am (fcc) transformation in Cu-Zn alloys has been studied isothermally by pulse-heating the retained ß phase from room temperature to the reaction temperatures. The transformation is found to occur only in the single-phase a region of the equilibrium diagram. The massive growth rate is of the order of 1 cm per sec and is constant at each temperature, usually after a delay time of some milliseconds. The delay time depends on the reaction temperature in C-curve fashion, while the growth rate increases monotonically with temperature over the single-phase range. The absence of isothermal massive transformation in the two-phase region does not arise from slow growth rates at such temperatures, but because the reaction cannot get started there. It is proposed that the massive transjormation initiates at small preexisting a particles which have rejected zinc into the surrounding 0 matrix. Only within the single-phase region can these particles consume the excess zinc during diffusion-controlled growth and thereby accelerate to the steady-state massive growth rate. The onset of massive growth marks the end of the delay time, and the growth rate then becomes interface-controlled. These isothermal transformation characteristics explain why the usual composition range for massive-kinetic studies by quenching is so limited. The same principles can be extended to more complex alloy systems by recognizing that the single-phase region in which the massive transformation can occur may not be stable with respect to phases not participating in the reaction. MASSWE transformations are now recognized as a regular class of solid-state reactions involving no compositional change (like martensitic transformations) and no shear displacements (unlike martensitic transformations). The name was first coined by Greninger1 in 1939 to describe the coarse grains of fcc a solid solution generated via a fast reaction from the parent bcc 0 solid solution in Cu-A1 alloys. However, some 9 years earlier, phillips2 had already described a similar transformation in the Cu-Zn system. The fact that the massive a formed as a single phase during drastic quenching from the 0 region of the equilibrium diagram signified that compositional changes were precluded. and the reaction was presumed to take place as in a one-component polymorphic transition by nucleation and growth. Phillips also observed that the occurrence of the massive transformation in the Cu-Zn system was extremely sensitive to alloy composition. For example. in a Cu-37.3 at. pct Zn alloy. the ß — am (am = massive transformation product) reaction was found to predominate and was not suppressed by iced-brine quenching from the 0 region. whereas at compositions greater than 38.3 at. pct Zn the massive reaction did not appear at all. Knowledge concerning massive transformations has bee11 substantially enhanced over the years by Massalski and his coworkers; an excellent summary of his papers and the current understanding of this type of reaction has been published recently by Barrett and ~assalski." he massive transformation product grows in roughly nodular form. often with irregular boundaries but sometimes with almost planar interfaces. The latter may have simple crys-tallographic indices relative to the 0 matrix. or the indices may be complex just as in the case of mar-tensites.'1 Little is known about the existence of orientation relationships between the massive and parent phases. A striking feature of massive transformations is that the massive units start almost exclusively at grain boundaries of the parent phase and frequently propagate on a broad front across matrix grains and grain boundaries of various orientations. Because of the rapid growth rate, it is thought that the interface motion is controlled. not by long-range diffusion. but by thermally activated atom jumps across the transformation boundary.

Jan 1, 1970

By K. Oraee

The empirical rock failure criteria play an important role in predicting the mechanical behavior of rocks, since affecting parameters on the behavioral properties of rocks are complex and numerous. Usually the empirical failure criteria are obtained by statistical methods, namely by means of fitting the mathematical function onto the experimental data. For evaluation and verification of the results, however, the quality and accuracy of the fit must be considered. This paper studies the efficiency and accuracy of conventional empirical rock failure criteria using a new approach, which is based on the analysis of uncertainty amplitude on the constant parameters of each criterion. The approach adopted here, is based on the combination of some parameters such as Mean Squared Error (MSE), Root Mean Squared Error (RMSE), type of function, degree of freedom and the confidence level of constants. Correlation coefficient (R2) is then a comprehensive test and can be used effectively for comparison and accuracy of empirical rock failure criteria.

Jan 1, 2012

By Peter E. Price

Salt dome hosted metallic sulfide deposits are the product of a complex evolutionary system involving halokinesis, cap rock development and diagenesis, and the generation, migration, and accumulation of basinal brines and hydrocarbons. Hydrocarbons play an important role in: (1) the production of calcite cap rock which hosts some of the metallic sulfide and sulfur concentrations, and (2) the generation of the reduced sulfur available for metallic sulfide precipitation and sulfur formation. Hydrocarbons and related fluids also are involved in the transporta¬tion and remobilization of the metals. Hydrocarbon consumption, in the course of cap rock development and sulfide mineralization at Hockley dome, is estimated to have been 6.4 million barrels of oil or 114 million cubic feet of methane. Mineral textures, including cap-rock banding, sulfide bands in anhydrite, and fine sulfide mineral banding indicate both episodic fluid influx and fluid compositional differences through time. Features such as pyrite "shells" and sphalerite and marcasite hemispheres may have been localized by hydrocarbon droplets and /or bacterial colonies. Marcasite mineralization in shallow strata above and flanking Hockley dome is best developed over the western and southern parts of the dome. This pattern mimics the known distribution of sulfide mineralization, which is dominantly marcasite, in the underlying cap rock. The iron sulfide paragenetic sequence in the sediments is pyritohedral and cubic + pyrithohedral pyrite followed by marcasite which is encrusted by cubic pyrite. Sulfur isotopic averages for the three stages are +20.8, -20.2, and +6.4 per mil, respectively. These values generally coincide with cap rock sulfate (+20 per mil), cap rock hosted metallic sulfides (-20 to +4 per mil), and sulfur in hydrocarbons (+5.8 per mil). Hydrocarbon compositions indicate provincial variations in oil composition and generation history. Long Point and Boling domes, which have an intergrown sulfide-sulfate-sulfur mineral assemblage indicative of mixed reducing-oxidizing environment, contain oils that are less mature than Hockley dome which appears to be more mineralogically segregated. Sterane biomarker compositions of the oils at Hockley, Long Point and Boling domes indicate a local, dominantly terrestrial source. An oil sample from supracap sandstones on the northeast flank of Hockley dome contained over 750 ppm combined Fe, Zn, Pb, and Co, indicating that hydrocarbons are carrying or remobilizing metals. Cap rock calcite and anhydrite also exhibit provincial variations in strontium isotopic ratios. Calcite and anhydrite cap rocks from several sulfide mineralized domes in the Houston diapir province have strontium isotopic ratios that are more radiogenic than Jurassic sea water (>0.7078). A calcite sample within massive sulfides at Winnfield dome also has a high 87Sr/86Sr ratio (0.7085). Variations in strontium isotopic ratios with strontium content indicate the mixing of at least three Sr-bearing fluids in the cap rock environment, one of which may have been the metal carrier. Anhydrite residues from diapiric salt have strontium ratios up to 0.7100, considerably more radiogenic than Jurassic seawater. These high ratios indicate either that salt and anhydrite recrystallized sometime post-Jurassic in the presence of a fluid with a high 87Sr/86Sr ratio, or that they precipitated in the Jurassic from a fluid with a higher 87Sr/86Sr ratio than Jurassic seawater. Salt domes with cap rocks containing metallic sulfides have only been found in basins that have geopressured zones. Waters from geopressured zones in the vicinity of mineralized salt domes have salinities that are two or more times higher and iron and base metal concentrations that are three to one thousand times higher, than geopressured fluids from other parts of the basin.

Jan 1, 2013

Laboratory electrical resistivity measurements of rocks are reviewed. Inductive and galvanic methods are discussed together with the ten important experimental factors which should be considered in an investigation.These experimental factors are electrodes, sample preparation, measurement errors, temporal current variations, current density, frequency, electrolyte composition, electrolyte saturation, pressure, and temperature.

Jan 1, 1969

By Tom Ireland, Tony Rock

The proposed 1.83km long twin bore A3 Hindhead road tunnel planned for contruction in 2008 is being delivered under a Highways Agency Early Contractor Involvement (ECI) contract. The proposed construction methodology is progressive mechanical excavation of a horseshoe shaped tunnel with shotcrete installed close behind the face using robotic spraying equipment. The tunneling medium is a ‘soft rock’ sandstone for which there was little previous tunneling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240m long portal section though sandy material utilising a steel pipe umbrella is also required. This paper describes the development of the tunnel planning and design including the most recent developments in UK road tunnels, and the innovation included in the ‘permanent’ primary lining design.

Jan 1, 2007

By Steven Hoerger

Newmont Mining has a large, integrated gold-mining operation in northern Nevada with several mines, stockpiles and processing facilities. There are more than 90 defined metallurgical ore types and more than 60 defined gold-recovery process options. Newmont developed a mine plan and process model to take better advantage of the available synergies at its Nevada mines. This plan includes a mixed integer and linear programming optimization tool. This system is maintained and operated by a Nevada planning group. Standard in-house planning software tools and methods have been implemented at all mine sites. These changes have allowed a reduction in mine engineering staff and have increased the effectiveness of mine planning.

Jan 1, 1999

By G. F. Jenkins, P. S. Hobden

Toronto as a geographical area provides an exceptionally wide variety of subsoil stratiphication. Tunneling consequently required a very wide range of adaptabilities to meet its changing conditions. This discussion will provide a summary of work performed in both earth and rock formation using three of our recent works to describe a Contractor's experience. The general subsoil stratigraphy is known to consist of deposits laid down during the Illionian Glaciation followed by the Samgamon Interglacial Stage and finally the Wisconsin Glaciation. All these deposits are underlain by shale bedrock of the Dundas formation. As a whole the Dundas formation is predominantly a greyish blue, thinly bedded shale. The engineering characteristics of the shale vary considerably, however, between a blue clay (argillaceous) shale and a much lighter (in colour) silty and sometimes sandy (arenaceous) shale, and occasional limestone layers. The Illionian deposits are usually found to be layers of pebbly clay till and an overlaying layer of contorted varved-clay. These glacial deposits can be overlain by a thick layer of sandy silt to silty sand which is identified as the Samgamon Interglacial sediments. Because of the action of erosion the Wisconsin till sheets, many times separated by interstadial sands, can vary greatly in their number of layers from zero to three or more.

Jan 1, 1997

By A. W. Frolli

This paper, describing the open-cut mining milling, and cyaniding methods and costs at the Yellow Aster gold mine, is one of a series being prepared by the Bureau of Mines on similar practices in the United States. It is presented primarily to show methods and costs of mining and treating low-grade gold ore on a large scale.

Jan 1, 1940

Most types of nuclear power reactors use uranium dioxide fuel. Power reactors using natural uranium dioxide fuel are of special interest to countries such as Australia that have their own uranium supplies. A wide range of uranium dioxide powders can be fabricated and the ideal one flows readily, presses without the need for binders or lubricants, sinters to the required density and gives low reject rates at all fabrication stages. Sinterable uranium dioxide is usually produced via the ammonium diuranate route.The Australian Atomic Energy Commission is aiming to demonstrate production of nuclear grade uranium dioxide from Australian concentrates, improving technology where possible. Details are given of the dissolution, solvent extraction, precipitation, filtration, drying, and· calcination-reduction steps. Solvent extraction from sulphate media is also under study with a view to developing a process to produce a nuclear grade product at the mine treatment plant site.

Jan 1, 1970

By Peter Kowalczyk

Magnetic surveying and map production is well established in land based mineral exploration. Magnetic data are routinely used to map geology in covered terrains, to estimate the depth to basement in overburden covered areas, and to identify altered zones, mineralization, bedding attitudes, and fault networks both regionally in map view, and through interpretation to depth in 3D. Best practices for magnetic survey methods and magnetic interpretation exist in all areas of land based geophysical survey methodology - mineral exploration, hydrocarbon exploration, geological mapping, archeological mapping, and in military applications. At sea, and particularly under the sea, sophisticated magnetic surveys are being done, but it can be argued that these are primarily in niche applications, for example in naval mine-hunting and UXO applications. Magnetic data is not normally collected on AUVs and ROVs conducting mapping and hydrographic survey operations. OFG has developed physical and mathematical calibration routines so that magnetometers can be mounted directly onto AUV and ROV bodies where significant heading errors and magnetic gradients exist. This simplifies the routine deployment of magnetometers on AUVs and ROVs for mineral exploration and other magnetic survey applications without the need for towed bodies, ungainly mounting frames, or degaussing of the survey equipment. Our experience shows that magnetometers can be operated routinely on AUVs and ROVs and that with careful processing useful maps can be produced routinely at low cost.

Sep 1, 2014

By Raymond J. Pichette

"Aeromagnetic data can be useful in helping to delineate structures and rock types in gold exploration. Magnetic anomalies associated with Archean volcanic belts in northeastern Ontario can be quickly and effectively analyzed in profile form with the use of model curves. The model curves help to locate contacts between strata. They also help to estimate the magnetite content of the rocks and their depth beneath overburden.An aeromagnetic map of part of Catharine Township, Ontario has been analyzed with the aid of model curves. Several magnetic rock types, potential fault zones and areas of relatively thick overburden were delineated.IntroductionIn any exploration program, a good understanding of the stratigraphy, rock types and structure enhances the possibility of success. For example, environments which host gold deposits in the Abitibi Volcanic Belt may be characterized as follows (Jensen, 1980; Pyke, 1980):(I) They have major faults, especially as tectonic boundaries between volcanic piles which include mafic and ultramafic rocks and clastic sedimentary rocks or gneisses.(2) They have subvolcanic felsic intrusions.(3) They have extensive carbonitization, with or without carbonate and sulphide-facies iron formation.In all cases, delineation of structure and rock type should be a major objective in exploration. The analysis of magnetic data can be a useful tool in this task. This paper is presented with the purpose of describing the application of the magnetic method to gold exploration in Archean volcanic terrains.Magnetic AnalysisTotal-intensity magnetic contour maps can be used to discriminate rock units according to differences in magnetization. However, because of smoothing of texture resulting from the compilation procedure and the fact that survey lines are widely spaced, contours should not be directly used for quantitative analysis. A much more definitive means of magnetic analysis is provided by the use of the original profile or chart recordings. Model curves provide a basis for analyzing these profiles both accurately and rapidly."

Jan 1, 1982

Green policies have gained momentum since the 1972 Stockholm, Environment Conference. The environmental movement has influenced political initiatives both in New Zealand and abroad. Governments and international institutions have addressed local, regional and global environmental issues with varying degrees of success. New Zealand so far has not supported the United Nations' call for sustainable development in a consistent manner. New institutions and new rules for resource management mean there are opportunities to look after the land in different and more ecologically sensitive ways than has happened in the past. The increasing influence of regional councils in resource management planning will have important implications for mining and mineral exploration. These trends are discussed and possible future events outlined. Green policies have gained momentum since the 1972 Stockholm Environment Conference. Environmental issues are now global and the twentieth year Environment Conference planned for 1992 is likely to see new commitments made by world leaders and their national governments. Green politics may be the popular trend of the moment but green principles of managing the earth's resources are here to stay. There are many businessmen, many technologists, and many politicians who have hoped that the environmental movement was a passing fad and would fade into oblivion. The evidence is otherwise. Far from passing into oblivion, the environmental movement is growing rapidly. Each year brings further scientific data that indicates mankind is on a self destructive course unless we learn how to better manage the earth's natural resources. This information has contributed to a growing population of environmentally aware people. In the last 20 years there have been messages of concern about a population increase out of control and the energy crisis which focused on dwindling oil stocks. The issues are all interrelated including the present global issues of climate change and thinning ozone layers. The attention being given the messages by the United Nations and member states requires similar attention by industry. The problems have been identified; the challenge is to determine what should be done about them. Every challenge brings new opportunities and the future need not be doom and destruction. Mining is seen by some of the environmental action groups as unnecessarily destructive of the environment, but I do not see mining ceasing in the next few decades. Rather, the rules will be clearer with some areas excluded from mining, the methods of extraction will improve, the technology of processing will become more sophisticated and restoration of mining sites will be not only normal practice worldwide, but the end result may leave no hazards, may enhance the landscape and may result in acceptance of the industry by the general public. For that to happen, commitment and cooperation is required between the industry, the government, and society. As an Officer of Parliament my role is to review the system of agencies and processes established by Government for allocating, using and preserving natural resources and to report whether the system is maintaining and improving the quality of the environment. I also have a responsibility to see that the environmental planning and management carried out by public authorities is effective. That Ineans I have a keen interest in how the mining industry is administered by New Zealand public authorities, including Ministers of the Crown and district and regional councils. Today I intend to review the approach to resource management being taken by international agencies and by the New Zealand Government, and to comment on how environmental impact assessment for mineral exploration, as well as mining, may be administered in the future.

Jan 1, 1990

By Carlos Magno Palacios Arbizu

La calidad total es la estrategia que busca la mejorar la productividad y eficiencia de los productos que ofrece -en tanto sean reconocidos por este valor-, de forma que genera competitividad en las organizaciones peruanas y se presenta como respuesta a nuevos enfoques de gestión surgidos ante el proceso de globalización. En este sentido, el presente trabajo analiza la forma del avance en el nuevo enfoque de gestión de las empresas mineras, para así proponer alternativas de tratamiento e implementación de un modelo basado en la Calidad Total, de manera que esté alineado dentro de un sector que tenga características propias y diferenciadas de organizaciones de otros sectores productivos.

Sep 12, 2005

By Shawn Collins

BACKGROUND The history of the Pine Point Mine is a rich one. This property once boasted one of the largest and most profitable lead-zinc mines in Canada's long and storied mining history. The Pine Point mine used open pit technology to extract the ore, but they faced several challenges. In addition to logistics problems with haul distances and metal prices, the mine faced the challenge of a large in flow of water from the Great Slave Lake. Eventually, the Pine Point Mine was closed leaving behind a large deposit of lead-zinc ore. Following the closing of the Pint Point Mine, Tamerlane Ventures Inc. acquired this property which includes approximately 70 million tonnes of lead-zinc reserves. The initial phase of this project will concentrate on the R-190 deposit as a test site to prove their new approach for extracting the ore. The R-190 reserve is believed to have approximately 1,014,000 million tonnes of high grade ore varying from 5% to 52% combined lead-zinc. Once the pilot project proves the approach is valid, the process will be repeated in approximately 33 other ore bodies on the property. This paper is written to discuss the design process to determine the most effective means of placing production and service equipment in the same shaft. Currently the design work and the mining scheme is complete, but lead-zinc pricing has prevented Tamerlane Ventures Inc. from moving forward with the project.

By Tumilty JA, Schmidt CG

Sulphide ion is a powerful poison in gold cyanidation, however, the detrimental effect is less severe in plant practice. This is thought to be due to the presence of depassivating elements in the ore, mainly lead. Trace amounts of lead can counteract the poisonous effect of considerable amounts of sulphide. The reaction is instantaneous and is likely to be a direct involvement in the electrochemical surface reaction. Lead addition cannot be regarded as an all-round cure when experiencing poor leach efficiencies. A possible beneficial effect depends on the mineralogy of the ore and has to be determined individually for every material.

Jan 1, 1989

By Jon Y. Kaneshiro, Sean A. Menge, M. Luis Piek, Brian Barker

The Lake Hodges to Olivenhain Pipeline project is part of a 40-megawatt pumped storage project linking two reservoirs as part of the San Diego County Water Authority’s $939 million Emergency Storage Project. Seeking to expedite project completion, the project was advertised as Design-Build, a first for the owner. Awarded to Kiewit Pacific with Parsons as designer, the 1,750m (5,700ft) long, 4.25-m (14 ft) horseshoe tunnel was excavated with conventional drill-and-shoot technique. The mining method was well suited to deal with the shear zones, the very abrasive rock, and 13.3% and19.6% grades. At the apex of the alignment, a 60m (200ft) by 3.6m (12ft) diameter raisebore shaft with surge chamber to protect against pump malfunction was constructed. Upon completion of mining, the tunnel was lined with a 3m (10 ft) diameter high strength steel pipe. Scheduled to come on-line by January 1, 2008, the Lake Hodges to Olivenhain pumped storage project is valued at $108 million, delivering a reliable source of water in emergency situations and electricity-generating capability to meet the growing demands of the San Diego region.

Jan 1, 2007

By R. L. J. Phillips

"The environmental impact of the Rabbit Lake project is presented. Baseline data for fish, water, air and radon collected in 1973, 1975, 1980and 1986, are compared with post-development environmental monitoring data. Predicted environmental impacts for the developed Rabbit Lake and B-zone deposits are compared to the actual impacts. INTRODUCTIONThe environmental impact of the Rabbit Lake project has been documented through the years in several submissions to the government agencies. In 1972, the environmental baseline study for the Rabbit Lake area was completed prior to any mining activity at the Rabbit Lake pit (Fig. 1).Sampling concentrated on Hidden Bay and Pow Bay, which received the treated effluent and the waters drained from Rabbit Lake respectively.A second baseline study was done on the Collins Bay area in 1980(Fig. I) in preparation for the mining of the B-zone pit. The detail in this study was considerably greater than the detail in the previous study. Collins Bay and Harrison Peninsula were the areas sampled. The B-zone deposit is being mined at present.With the discovery of the A-zone, D-zone and Eagle Point deposits, it was decided in 1986 to begin proceedings to obtain approval from Saskatchewan's Department of the Environment, and from the Atomic Energy Control Board to develop these deposits.In preparation, a third baseline study of both the Rabbit Lake and Collins Bay areas was done in 1986 and 1987. The emphasis was to establish the baseline at the three new deposits, to quantify the actual impacts of the existing Rabbit Lake operations and to confirm the Collins Bay B-zone (1980) impact predictions. The new deposits will allow us to continue to produce uranium into the future. In January 1988, Saskatchewan approval was received.Since 1975 in the Rabbit Lake area and 1980 in the Collins Bay area, routine environmental monitoring has been done. This has resulted in one of the largest and most comprehensive environmental data bases in North America in mining. By the time the Eagle Point deposit is mined to completion, there will have been data collected for approximately 40 years.Further discussions follow which describe the impacts of the past (1972 to 1984), the present (1985 to 1987) and the future. In addition, the past and present performances and the future plans of the .waste management systems will be discussed."

Jan 1, 1989

By John Parianos

"Seafloor mining provides significant potential economic benefits for many Pacific nations that may be "land poor" but "coastline rich," meaning they have the potential to utilize and profit from the mineral wealth within their Exclusive Economic Zones that extend 200 nautical miles (360 km) out from their coastlines. The Independent State of Papua New Guinea (the State) recognizes this tremendous opportunity and is taking a leadership role in this emerging industry by becoming a 15% partner in Solwara 1 (with an option to increase their investment to 30%).The Solwara 1 Project has been gaining momentum since Nautilus Minerals and the State signed an Agreement on April 24. This new agreement with the State in which they have staked a minimum 15% interest as a meaningful partner, underscores the State’s continued and widespread support for the Project. Signing of this Agreement was a historical occasion and a milestone achievement for Nautilus Minerals and the people of PNG.The machinery being built for the Solwara 1 Project is taking shape. The Seafloor Production Tools are now over 90 percent complete. Assembly of the biggest tool, the Bulk Cutter, was completed in April this year and assembly work on the Collecting Machine and the Auxiliary Cutter commenced in May and June this year respectively. The Riser and Lifting system, which will be used to transfer the mined material from the seafloor to the surface within an enclosed system, is over 50 percent complete. The critical path for the Solwara Project is to secure a suitable vessel arrangement. Nautilus aims to have this completed by the end of this year."

Sep 1, 2014