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By M Norbert, P Mok

The mainline running tunnels for Legacy Way comprise of two-lane tunnel boring machines (TBM) driven tunnels. The length of the TBM tunnel section is approximately 4.2 km. The TBMs employed are double shield TBMs. Typical support to the segment ring while advancing a double shield TBM comprises of filling the excavated annulus between the ground and the segmental lining by injecting pea gravel, followed with primary grouting to fill between the pea gravel some distance behind the excavated face. The methodology adopted for the Legacy Way project, however, did not follow this typical approach, instead, two component grouting of the annulus was carried out.Where the annulus is typically filled with pea gravel, support is provided to the segment ring very close to the end of the tail shield, whereas in the case of two component grout this is not practical as the risk of grouting in the tail shield is high. The staging of the two component grout injection, the grout early age strength properties become key issues in ensuring that the segment ring leaving the TBM tail shield is stable and can support the necessary external loads.Two-component grout is a grout with two components, cementitious grout (component A) and accelerator (component B), commonly adopted for earth pressure balance (EPB) TBM. The grout reaches its thixotropic state in a matter of seconds providing initial support for the segment rings. Manual injection of two component grout to fill the bore annulus was carried out in stages leaving a portion of the segment rings unsupported. Ring stability during TBM advance was provided by a combination of ram thrust and the segment circumferential joint shear connectors.This paper outlines the design considerations such as rock load derivation by probabilistic analysis carried out utilising the software JBlock, 3D finite element analyses using the software Strand7 for ring stability and the testing and back analysis of the shear connector load bearing behaviour. In particular, the actual available capacity of the shear connectors against their published capacity by supplier was discussed.CITATION:Mok, P and Norbert, M, 2014. Tunnel boring machine excavation stability – double shield tunnel boring machine advance with partially grouted annulus, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 51–62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Guy T. Jr. McBride

World food production is not matching the exploding increase in world-population. Since arable land is limited, ways are being sought to increase yields by turning_ to fertilizer. Phosphate, an essential fertilizer ingredient, is undergoing a period of growth unparalleled in history. The United States is at once the world's largest producer of food and of phosphate rock. Both food and fertilizer output in the United States are being enlarged to meet the demands posed by the threatening world food crisis. New phosphate deposits are being developed in Florida and North Carolina to assure the United States' continued preeminence in this vital resource. Large fertilizer complexes are also being constructed with an eye to both domestic and foreign markets. The growth of the U. S. phosphate industry has been characterized by developing technology in the processing and distribution of phosphate raw materials. The trend from low analysis to high analysis materials accompanied by a change from a large number of small fertilizer plants oriented toward the marketplace to a fewer number of large plants located at the raw material source is illustrative. These changes in technology and distribution have also been important factors in the development of new mining areas in Florida, the Western States and North Carolina.

Jan 1, 1966

By . Menad Gaballah I

Three samples of solid wastes generated by the non ferrous metallurgy were characterized. These residues contain up to 42 % of valuable metal compounds ( Cu, Pb and Zn ) and 23 %of toxic compounds t As, Hg, Cd and Se ). These sample were subjected to thermal treatments between 200 DC and 800 °C in controlled oxidizing. reducing and chlorinating atmospheres. Up to 99 % of As, Cd, Hg and Se were eliminated from these industrial wastes. Cu, Pb, and Zn compounds were concentrated in the treatments' residues of these samples. A Global Decontamination Factor' GDF ' was defined to measure the efficiency of the elimination of toxic elements and the recovery of valuable elements for a specific sample submitted to a given treatment. It seems that the thermal treatment in a reducing atmosphere was the most efficient in decontaminating these solids and the concentration of valuable elements. a.

Jan 1, 1995

By Langtry E. Lynd

Ilmenite concentrates prepared from beach and dune sands of Florida, India, Australia, and other localities deviate to varying degrees from the theoretical composition of pure ilmenite, and generally contain more Ti02 than the formula FeTiO3 would indicate, and some Fe203. This variation in composition is due to different amounts of altered ilmenite in the concentrates.(l) The alteration has been shown to take place by oxidation and leaching of the iron in ilmenite, to yield residual products consisting of amorphous or very finely crystalline titanium dioxide and ferric oxide, Other studies (2) have stressed that ilmenite may alter first to an amorphous titanium-iron oxide, or to an amorphous mixture of titanium and iron oxides, with later alteration to crystalline titanium dioxide. There has been some speculation as to whether alteration of ilmenite is usually caused by weathering or by hydrothermal processes,(3, 4, 5) Three main methods of approach were used to study the mechanism and rate of ilmenite weathering, (1) Etch tests were used to learn the relationship between crystallographic orientation and the rate of chemical attack on ilmenite. (2) Altered ilmenites in New Jersey sands were compared with ilmenite in rocks of the area from which the sands were probably derived, (3) Experiments were carried out to determine at what rate, and by what agents, originally fresh ilmenite could be altered in the laboratory under simulated weathering conditions.

Jan 1, 1959

By A. B. Pederson, G. E. Bartlett

As a part of our study of how coal mine dusts injure the lung we have studied the effects of dusts and dust-exposed pulmonary alveolar macrophages (PAMs) on the growth of lung fibroblasts (LF). Fibroblasts were cultured near confluence in low-serum medium, either alone or in the presence of dusts, dusts plus PAMs, dust leachates or superriatants of dust-exposed PAM cultures. We report here provisional conclusions, based on initial observations. Rat LF were relatively unresponsive to direct effects of dusts, showing weak stimulation in only a few cultures, and there was no evidence that dust-exposed rat PAMs had released any growth-regulatory products. In contrast, guinea pig cells were more responsive to the dusts. The pattern of responses was quite complex. Three of the dusts stimulated LF directly (with no mediation by PAMs). Two dusts were essentially inert when added directly to fibroblast cultures, either with or without PAMs, but their leachates were active: 867 leachate was inhibitory and RF leachate was stimulatory. Dust 1361, either directly in the cultures or as an aqueous leachate, was stimulatory, and it activated cocultured PAMs to stimulate LF growth; however, supernatant products of 1361-stimulated PAMs were inhibitory. Direct exposure to 1192 stimulated LF, but its leachate was inert; cocultured PAMs exposed to 1192 had weak stimulatory effects, but supernatants of 1192-exposed PAMs were mildly inhibitory. MP3-3 had effects similar to 1192, except that the cocultured, dust-exposed PAMs had no effect on growth. We conclude 1) that guinea pig lung cells are more responsive to dusts than are rat lung cells, 2) that dusts can influence growth of LF by four kinds of interaction (by direct dust-cell interaction, by release of soluble dust components into the culture medium, by activating P AMs to exert direct cell-cell interactions, and by activating P AMs to release growth regulatory products into the culture medium), 3) that each kind of interaction may be neutral, inhibitory or stimulatory, depending on the dust tested, 4) that four of the dusts tested were neutral, inhibitory or stimulatory, depending on the assay (the fifth <lust was either neutral or stimulatory), and 5) that the effects of soluble mediators (leachates or products of activated PAMs) frequently did not correspond with the direct dust-cell or PAM-fibroblast effects. These results suggest that the nature of the dust-lung interaction at the level of cells and molecules is exceedingly complex. These observations need to be confirmed and extended to determine what characteristics of the dusts determine the nature of the cellular responses, and to determine which patterns of responses are detrimental and which are beneficial in the overall health of the dust-exposed lung.

Mar 1, 1989

By W. N. Hamilton

As a result of a test-drilling program conducted by the Research Council of Alberta in 1968, a gypsum deposit averaging 30 feet in thickness, with a chemical purity of 84 per cent gypsum, has been proven to underlie the Clearwater River valley for a distance of 18 miles at depths ranging from near-surface to 300 feet. This and other subsurface deposits in the vicinity of Fort McMurray, Alberta are the product of local hydration of anhydrite beds believed to be the water-insoluble remains of the leached Prairie Evaporite formation of Middle Devonian age, the thick salt section of which is preserved down dip. The effects of salt solution are seen in the disturbed bedding and the intermixture of greyish green shale with gypsum in the core, the shale content being responsible for the rather low chemical purity of the deposit. A similar gypsum deposit, but probably of higher purity, is postulated to occur beneath the Athabasca River valley about 60 miles north of Fort McMurray.

Jan 1, 1969

By W. Petruk, M. J. Matos

An aplite ore from Guarda in northern Portugal, containing albite, microcline and quartz and muscovite gangue was studied to identify conditions for extracting the feldspar minerals. The large amounts of quantitative mineralogical data needed to evaluate grinding behaviour were provided by automated image analysis. The images were acquired on polished surfaces by measuring back-scattered electron signals produced with a microprobe. Minerals were identified from X-ray spectra and discriminated by grey level and element-characteristic X-rays. The quantities and size distributions of the minerals were determined by measuring thin sections of unbroken ore to predict the grind required to liberate the feldspars. The ore was then ground to -1.7 mm, polished sections were prepared from sieved fractions and the quantities of mineral species and apparent total liberation were determined by analysis. The predicted and measured liberations were compared and the grinding behaviour of the ore interpreted. In an appended correction, the correct version of Equation 1 is represented and Tables 3 and 6 are revised to consider all size fractions, including those coarser than 300 micrometres, in calculating the total liberation from King's fractional liberation

Jun 18, 1905

By T Ireland, S Eratne, W Newns, P Spies

The approach to risk management during the procurement of major projects often has a significant outcome on the ultimate delivery of a project. The NZ$1.4 B Waterview Connection project is the largest and most complex project yet undertaken by the New Zealand Transport Agency (NZTA) and the procurement process for an alliance contract was refined to provide compliance with the International Tunnel Insurance Group (ITIG) Code of Practice for Risk Management of Tunnel Works (TCoP). The principle of shared risk within an alliance incentivises a common understanding of project risks prior to finalising the alliance agreement and therefore enables superior risk management through design, construction and beyond. Risk management practices need to be instigated well in advance of commercial phases, so that commercial competition does not lead to a significant elevation of project risk. In particular the practice of gaining commercial advantage by taking on a potentially unmanageable level of risk is one of the outcomes to be avoided by the TCoP.During the procurement phase the NZTA placed high value on design and construction mitigation measures proposed in order to address ground risks, as is appropriate for a major tunnel project. In order to achieve alignment on the level of geotechnical risks an Alliance Geotechnical Baseline Report (AGBR) process was developed.This paper describes the measures taken during the procurement process to achieve certainty with respect to outcomes and minimise project risks whilst also achieving value for money. Refinements to the procurement process to ensure compliance with the TCoP prepared by the International Tunnel Insurance Group (ITIG) are described along with the AGBR process applied as part of a suite of measures to achieve a successful procurement outcome.CITATION:Ireland, T, Spies, P, Eratne, S and Newns, W, 2014. Risk management and use of a geotechnical baseline report for a competitive alliance procurement?process, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 553–562 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Edwin C. Reeder

This is one of a series of papers dealing with mining methods and costs prepared under the sponsorship of end in cooperation with the United States Bureau of Mines. The mining methods described in this paper are those used in one of the large mines producing fluorspar in the Kentucky-Illinois fluorspar field, located in southern Illinois and western Kentucky on the Ohio River. The occurrence of ore and the methods of wining are similar to those in other mines in the district; therefore information regarding methods and the results obtained should be of interest. Improvements in methods have been made as experience developed the need of them. The trine is situated at Rosiclare, Ill., on the Illinois Central Railroad, and shipments are also made b r barge on the Ohio River.

Jan 1, 1930

By R. J. Hundhausen

The Takilma-Waldo copper district in Josephine County, Oreg., was studied by the Bureau of Mines from September 1950 to April 1.951 and from December 1953 to April 1954. Funds for the investigation were provided by the Bureau of Mines and the California-Oregon Power Co., Medford, Oreg., on a cooperative basis. The copper mines in the district are credited with a total production of ore worth $1,700,000. Since 1933 the mines have been unproductive and, except for minor exploration, largely inactive. The history of the district indicates that the copper deposits were mined principally during periods of high metal prices.

Jan 1, 1956

By J. L. Ellenberger

The U.S. Bureau of Mines has cooperated with Cyprus Casa Grande Corporation Cyprus Casa Grande Mine, Cas a Grande, Arizona, since 1988 to assess the hydrology of an in situ leaching test facility. This work has resulted in an in situ design for leaching copper oxide ore that takes advantage of the increased mineral access associated with poor quality rock surrounding mine drifts. Blasting and bulkheads are used to produce readily-leachable rubble and contain and control solution movement, respectively. The design reduces the need for handling solution under high pressures in an injection/recovery system for in situ leaching of underground ore bodies. Early work at the site recognized a stress redistribution zone and increased transmissivity near drifts. Fracture data from a corehole oriented parallel to the dip of the ore body indicated an increase in fracture frequency around drifts a distance of 21 m (70 ft) away from the 5 m (16 ft) diameter drifts.

Jan 1, 1994

By Simón D. Strauss

El presente texto señala los factores que han influenciado el comportamiento de los precios de los metales no ferrosos desde el fin de la Segunda Guerra Mundial. Tras la finalización de este periodo bélico, se dio una inflación que afectó los niveles de precios de todos los productos, alterándose los costos de cuatro de los ocho metales no-ferrosos en la industria minera peruana. Para ello, se realiza un estudio comparativo de los precios estipulados durante la Segunda Guerra Mundial con los precios vigentes al 31 de octubre de 1969. Asimismo se analiza los problemas básicos de oferta y de demanda, encontrándose que la demanda es mayor a la oferta, pese al descubrimiento de nuevas reservas del mineral. En consecuencia, tanto el avance científico y tecnológico como el desarrollo de la competencia son factores de importancia en la tasa de mercado actual que necesitan evaluarse constantemente.

Nov 20, 1969

By A. Vilinska

The adhesion of Leptospirillum ferrooxidans bacterial cells onto the sulfide minerals pyrite and chalcopyrite was evaluated using two different physical-chemical approaches; thermodynamic and extended DLVO theory. For the parameters incorporated into calculations, the zeta potentials and contact angles of powdered solids and bacterial cells were acquired experimentally. The Hamaker constants essential for Lifshitz-van der Waals inter-action calculations were calculated following two different methods: macroscopic and microscopic. Adsorption tests were carried out at physiologic conditions to estimate the amount of cells adsorbed onto a mineral surface and the extent of alteration of that mineral surface in biobeneficiation. The free energy of adhesion was found to be negative for both minerals, indicating that the adhesion is energetically favored and preferred. The interaction energy diagrams of the total interacting force was also negative for the cases where the particles were charged oppositely; in the remaining cases, the total force was attractive after overcoming an energetic barrier caused by the repulsive electrostatic forces. Under the conditions of the adsorption test, the experimental results are in agreement with the theoretical; this suggests that the physical-chemical forces are crucial for bacterial adhesion.

Jan 1, 2011

By W. Z. Choi

In our previous work, a population balance model describing the simultaneous processes of size reduction and mineral liberation has been developed. The experimental verification of this model, however, has been limited to a binary mineral system containing only one composite particle class. When considering multiple classes of composite particles, the estimation of model parameters becomes much more difficult. In the present work, a procedure for estimating model parameters for a multiple composite class model has been developed. Emphasis is placed on the direct experimental determination of these parameters. The physical significance of the breakage rate function and the liberation function in characterizing the liberation process is also discussed.

Jan 1, 1987

By B. Numerov

A numerical proceeding of corrections with respect to topography is worked out for places near the station and a graphical one for the remote parts of the terrain. The description is clear and very detailed. The numerical proceeding is very similar to that of the Eötvös and Schweydar methods which are in use already. In both methods the levelling is accomplished in certain circles and fixed azimuths around the station. While, in using the Eötvös method, the height differences are directly inserted into the final formulas with regard to the foot of the instrument and in case of accurate formulas derived by Schweydar the height differences are calculated with respect to the center of gravity of the attachment, Numerov introduces functions A and B, the heights, of the terrain and of the center of gravity, which are to be inserted into the formulas.

Jan 1, 1929

By K. Papke

Nine western states contain significant barite deposits, but most deposits are in Nevada, which has been the principal western producer for more than three decades. Nevada produces about 85% of the total United States production, but about one-half of the barite consumed in the country is imported. Approximately 95% of the barite is used in drilling muds. Sharply decreased oil and gas drilling, starting in early 1982, severely depressed the domestic barite industry. Other problems for western barite include long distances to the areas of major drilling, high railroad-freight rates, and increased barite imports. Bedded deposits, formed by submarine exhalative processes, account for almost all western production, and reserves are large.

Jan 1, 1983

By Phillip N. Yasnowsky

"In this Bureau of Mines report, the Federal income tax treatment of mineral exploration and development expenditures is summarized, and changes in the tax treatment of these expenditures since 1951 are detailed and analyzed. Although no attempt is made to establish causal relationships, major tax changes favorable to exploration and development activities did occur in 1951 and 1966 when the Nation was engaged in military actions and the economy was expanding. More recent changes have been unfavorable to exploration and development and were parts of major tax reform efforts. INTRODUCTIONThis Bureau of Mines report discusses the Federal tax law provisions relating to mineral exploration and development expenditures. These provisions, contained mainly in sections 616 and 617 of the Internal Revenue Code of 1954 (Title 26 of the U.S. Code), apply specifically to minerals (other than oil and gas), and thus are of interest to the Bureau of Mines.Bureau of Mines involvement in this subject stems from the legislative mandate in the 1913 amendments to the Organic Act of 1910 (the Act creating the Bureau) to conduct economic investigations of the mineral industries. Congressional concern with the financial conditions in the economic and mineral industries was expressed more recently in the Mining and Minerals Policy Act of 1970 and in the National Materials and Minerals Policy, Research, and Development Act of 1980. The General Accounting Office recommended in 1976 that the Department of the Interior ""identify and evaluate laws and agency programs that affect maintaining and developing a sound and stable domestic mining and minerals industry"" (17, p. iii). 2Taxes, a source of revenue to governments, are a cost to private firms. Thus, taxes directly affect private sector profits, and unique tax provisions are designed to encourage (or discourage) activities such as agriculture, construction, or mining. Even the international competitiveness of the domestic mineral industries may be affected by taxes because many minerals are traded in world markets."

Jan 1, 1985

By J. S. Aronofsky

The areas are identified where the techniques of operations research have been applied in the petroleum industry. Particular emphasis is given to the linear program models that have been used for solving management problems. Of the entire gamut of applications for linear programming, attention is focused on the models that represent underground reservoirs. Such models could be used to help schedule drilling rig operations and to schedule oil production. A framework is established for placing the model for underground reservoirs in the proper perspective along with the models which represent other facets of the oil business. One of the remarkable phenomena of this century is the rapid growth in the size and&apos; complexity of human organizations. The mere size of modern business means that administrative decisions can affect vast quantities of capital and large number of people. Mistakes can be tremendously costly, and a single wrong decision can require years for rectification. Moreover, the pace of modern business is such that decisions are required more rapidly than ever before; the mere postponement of action can give a decided advantage to a competitor. It is not surprising that the increase in difficulty of decision making has been followed by efforts to put this activity on a more objective basis. The growing science of operations research, which relies heavily on the methods that have proved so successful in the physical sciences, is one aspect of these efforts.

Jan 1, 1962

By J J. McNee and, J Crusius, T F. Pedersen

The use of water covers is a globally-applied method for minimising acid rock drainage (ARD) and metal leaching. Although the subaqueous disposal of potentially acid-generating materials has been shown to effectively limit ARD, under certain scenarios, metal remobilisation can occur at circum-neutral pH. The following paper presents data from four case studies in which metal mobility from submerged mine waste resulted in degradation to water quality in the overlying water cover. Subcentimetre resolution profiling of dissolved constituents across the tailings-water interface (dialysis arrays), in conjunction with mineralogical information, were used to elucidate the controls governing metal mobility. The data illustrate four pathways of metal remobilisation, including: the release of zinc via the oxidative remineralisation of metal-rich organics at the tailings-water interface; enhanced remobilisation of arsenic as a result of anthropogenic eutrophication; the release of copper resulting from the pH-driven dissolution of treatment sludges; and the release of radium from uranium mill tailings due to the dissolution of radiobarite [(Ra,Ba)SO4] by sulfate-reducing bacteria. The results highlight the conclusion that the chemical stability of submerged tailings reflects both: the solid-phase characteristics of the tailings material; and the physical, chemical and biological characteristics of the depositional environment. In particular, the data illustrate that rigorous characterisation of both the waste solids and receiving environment must be performed in order to assess their compatibility. The results have relevance to the management of tailings repositories including constructed impoundments, pit lakes and natural lakes.

Jan 1, 2003

By G. Mihaylov

The basic principles of systems analysis are presented. A model has been designed to determine the location of the Main opening in the presence of three or more stock orebodies. The necessary condition is to find a location for the Collection point which is an essential element in opening up each orebody (stock). The model takes into account the total transportation costs from each orebody to the collection point. Three variants are considered provided that the orefield is divided into two levels at least: - a collection point is designed at every level; - a collection point is designed at the lowest level, i.e. where the so-called concentration level is formed; - the collection point is located at a point between the planes of the two levels; The effect of the depth of mining and mine output on determining the method of opening up the orefield has been analyzed by considering a vertical and/or an inclined shaft. A function has been constructed which allows for investigating in both a static and dynamic regime the capital costs for constructing the whole complex including the shaft. The character of the function does not allow finding the global limits. Therefore, it is of particular importance to specify the limiting conditions. In this case these are the flow capacity of development openings and the shaft. The basic groups of cost and natural indicators for assessing and selecting an optimal technological solution have been systematized. The combined analysis of the two approaches to finding the location of the Main opening and determining the mining method enables us to determine when an inclined shaft is best, and the depth at which opening by a vertical shaft has no alternative. Thus, a transition area is formed for which the selection of an optimal technological solution requires an analysis similar to that proposed in this paper. Conclusions are finally drawn which serve as a basis for determining the areas of application of each opening, including the use of a combined scheme of mine opening. The approach presented can be used in both investigating the possibilities for opening up new orefields and reconstructing existing ones in cases when the mining operations go deeper.

Aug 1, 2013