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By Finlayson EJ

New detailed mapping, micropalaeont- ology and isotopic dating have been successful in revising the stratigraphy of Woodlark Island. All Middle to Late Miocene intrusives and volcanic rocks have been assigned to the Okiduse Volcanics. In addition, the results demonstrate that the Tabukui beds and Wonai Hill beds (N9, late Early Miocene to earliest Middle Miocene) are a single unit. Similarly, the Nasai and Suloga Limestones are confirmed as a single stratigraphic unit as they yield similar foraminiferal ages (upper Te, Early Miocene), and both occur in the same stratigraphic position unconformably overlying basement Loluai Volcanics. Radiocarbon dating suggests a latest Pleistocene age for the upper Kiriwina Formation. Extensive Quaternary cover and low relief prevents detailed structural airphoto interpretation. In general, the structure is simple with all units on Woodlark dipping to the northwest a_4 exhibiting prominent local block faulting.

Jan 1, 1991

By B. C. Vargas

The Toulon tunnel project is a key component of the Highway corridor on the French Riviera between Marseille and Nice and is a fundamental transportation infrastructure for the region. The first design studies started in the 1960?s. The tunnel project is made of 2 separate tunnels: South and North tunnel. The North tunnel was built between 1992 and 2002 after 10 years of difficult construction (for example, on March 15th, 1996, a collapse of the tunnel in the ?Marchand Area? generated a sink hole in the city Center, causing 20 months delay). The South tunnel alignment runs parallel to the North tunnel at the same depth below Toulon historical downtown (20 to 40m depth with some areas with less than 10m of cover). The Risk management program was studied to be a State of the Art program in urban tunneling construction. The Hydro Geological Context The whole project area is covered with backfills and colluviums of 1 to 4m thick. The Schist, marls and sandstones, randomly distributed along the alignment below the first layer have different characteristics. While the Schist are pretty compact, the marls are fractured. The other layers have very different characteristics, and many faults are located along the alignment, especially in the limestones. The Breccia are heavily decompressed and deformable, as well as the other soils located in the Marchand Area. This 80m long area is where the settlements need to be controlled with an extensive monitoring program. The complete Geological profile is presented in Figure 1. [ ]

Jan 1, 2012

To many Australian Mining Engineers, we take it, the singular features of banket deposits are not as familiarly known as they would wish, possibly because in the majority of instances they are not in touch with the South African milling world, and have had little opportunity of studying the development of the banket beds, either from correspondence or literature. The writer hazards this opinion feelingly, because, when in Australia and before he had visited Africa, the utmost knowledge he was able to obtnin was a mass of conflicting theoretic discussion as to the agencies which formed the banket bed, without any practical hints as to their geological horizon, the rocks with which they are associated, the usual appearance and character of the ore, in fine, without that everyday detailed description which the miner requires when seeking information regarding mineral or metal deposit foreign in character to any that he has yet studied, or as yet had any opportunity of studying in his own country.The writer recognised that many more able men than he have from time to time discussed the features and formation of the banket beds of the land, notwithstanding which and feeling that many of his Australian colleagues have found themselves in a similar position regarding accurate detailed information respecting these African banket deposits as he himself was, he hopes that the present paper on the said deposits, as found on the fields under notice, will prove useful to some and of interest to all.

By B. J. Moore

This publication contains 14,242 analyses of gas samples from oil and gas wells and natural gas pipelines in 40 States and 24 foreign countries. These gas samples were collected in the period 1917-85 as part of the Bureau of Mines survey for helium occurrences. The gas analyses contained herein were made by several methods over the period covered. Analytical work on samples collected early in the period was done on the Orsat apparatus. The one-cut apparatus and four-cut fractional distillation equipment were added later. A mass spectrometer was acquired in 1949 and used for all gas analyses made after that time. From 1917 to 1978, helium analyses were made on special helium analytical equipment designed and built by the Bureau of Mines Helium Operations Laboratory. In 1978, this apparatus was replaced in the quantitative helium analysis work by a gas chromatograph.

Jan 1, 1987

By Jiwei Duan

The deformation and load transfer behavior of a single soil-cement column are studied with the finite element method. The results show that there is an effective length for a soil-cement column. Beyond this length, the settlement of the column is approximately equal to a constant. The effective pile length is introduced to the concentric cylinder approach (Randolph and Wroth 1978), and an analytical formula for estimating the settlement of a single flexible pile is presented. A second analytical formula for determining the effective pile length of a soil-cement column is obtained and an example shows that the calculated and measured results are in quite good agreement.

Jan 1, 2002

By C. C. Anderson

"While conducting investigations in connection with the helium program of the Bureau of Mines, the Cryogenic Laboratory has improved an apparatus for the rapid and accurate determination of the helium content of natural gas and gaseous mixtures derived from that source. The separation of helium is effected by the use of activated coconut charcoal which, when cooled to liquid-air temperatures, absorbs the nitrogen and other constituents of the gas, leaving the helium in a. spectroscopically pure state. This absorptive property of activated charcoal was discovered- by Dewar3/ in 1875. Several years later, while conducting their original researches on helium in natural gas, Cady and McFarland employed the charcoal method for the absorption and removal of the common constituents of natural gas and constructed an efficient apparatus in which this operation could be effected.4/ Shortly after initiating the government's helium activities during the World War period, the Bureau of Mines adopted, with Minor modifications, the Cady and McFarland apparatus and method of analysis. Seibel.5./ described this modified apparatus and method of procedure as part of a publication on helium-bearing natural gas. Subsequently, the Bureau's apparatus for helium analysis has been simplified and improved to facilitate more rapid and positive operation. The apparatus and method of procedure now being used by the Bureau of Mines Cryogenic Laboratory arc described in this paper.The personnel of the Bureau of Mines Cryogenic Laboratory has improved and brought the helium apparatus described herein to its present state of perfection. The writer's contributions have been-of minor importance, and he wishes to give the various members and former members of the laboratory staff full credit for the improvements they have made. He also desires to express his appreciation for suggestions and criticisms offered during the preparation of this paper to the following members of the Petroleum and Natural Gas Division, Bureau of Mines, which now includes the Amarillo Helium Plant and Cryogenic Laboratory: H. A. Cattell, chief engineer; C. W. Seibel, supervising engineer of the Amarillo Helium Plant; W. M. Deaton, chemist-in-charge of the Cryogenic Laboratory; and H. S. Kennedy.The quantitative determination of helium in a gaseous mixture is accomplished by the removal of the other constituents from the sample, either by chemical or physical Means, leaving only the helium which can be measured directly. Chemical methods, when applied to natural gas, require the burning of the hydrocarbons in oxygen, the, absorption of the resulting carbon dioxide in a caustic solution, the removal of the excess oxygen in a suitable solution such as an alkaline pyrogallate, and the elimination of nitrogen by sparking or by combination with hot calcium or magnesium.. Such procedures are very slow and tedious compared with the physical method which employs the absorptive property of activated charcoal to effect the separation of the other constituents from the helium."

Jun 1, 1934

By Hodjat] [Shiri

A 4-legged jacket structure was installed by an Offshore Installation Contractor (OIC) in the Persian Gulf. In addition to four open-end pipe piles, six conductors were installed by OIC. During the installation of the piles and conductors, some cemented layers were encountered, which had not been accounted for in the foundation design performed by an independent well known offshore geotechnical site investigation contractor (OGSIC). Six months later, the Drilling Company (DC) hired by Client to execute the wells, reported that all of the six conductors were presenting anomalies, such as vertical misalignments up to 10o and/or collapse of the conductors tip and mid height. The DC faced with serious problem in drilling of the wells and in spite of several times milling the conductors and spending 40 days unpredicted extra time, some of the routes could not be opened and Client lost millions of dollars due to direct and indirect associated costs and expenses. This paper presents a complete overview of all engineering, construction and specially geotechnical investigations and shows that how an inaccuracy in interpretations of the results of an offshore geotechnical site investigation as the main reason in this case study can cause serious damages to whole project with unbelievable time and cost impacts some times up to millions of dollars.

Jan 1, 2006

By A. Bascetin

One very important aspect of mining is deciding what material in a deposit is worth mining and processing, versus what material should be considered waste. This decision is summarized by the cut-off grade policy. The cut-off grade strategy for an open pit mine influences the annual cash flows and affects the net present value of a project. The optimization of cut-off grade strategy requires the knowledge of detailed operational costs, mining sequence, mining operation, processing, and product constraints, as well as the grade distribution of a given deposit defined by pit, phase, and different material types. Cut-off grade optimization algorithms have been developed in the past. The most common criteria used in cut-off grade optimization is to maximize the net present value (NPV). This paper describes the determination of a cut-off grade strategy based on Lane?s algorithm adding an optimization factor based on the generalized reduced gradient (GRG) algorithm to maximize the project?s NPV. The introduced algorithm is a windows based program developed at Virginia Tech that is based on a series of Visual Basic routines within a spreadsheet environment (Excel).The benefits of the methodology are demonstrated using a hypothetical case study. Keywords: Cut-off grade optimization, net present value maximization, generalized reduced gradient algorithm method.

Jan 1, 2007

By Donald F. Reed

Deposits of gray hematite occur in two districts in Talladega County, Ala., the Emauhee-Tallasechatch and Weewoka, both in the; vicinity of Wintorboro, 50 miles east of Birmingham. The deposits were investigated by the Bureau of Mines in 1945 and 1944. Approximately 15,000 feet of diamond drilling was done and 6,000 linear feet of trenches excavated and sampled.

Jan 1, 1949

By G. B. Harris

It has long been appreciated that chloride chemistry has a number of advantages over the more traditional sulphate route for both extracting and separating metals. Modern materials of construction, coupled with the development of a more cost-effective and efficient hydrochloric acid regeneration technology mean that chloride-based processes are now more competitive and attractive. Such processing routes are able to recover more of the contained metal values in a feed, including iron in a benign and/or marketable form, and particularly the so-called rare and rare-earth elements which are increasing in demand in our electronic age. These factors, therefore, add appreciably both to the overall economics of a project, but also offer a much more sustainable approach to our dwindling natural resources. Additionally, chloride-based flowsheets can be much more environmentally-friendly, offering practical alternatives to two of the biggest headaches faced by the industry, namely cyanide usage and the generation of red muds. This paper presents a brief theoretical background, focusing on the latest developments of ferrous iron oxidation and the low-temperature, selective hydrochloric acid regeneration process, which is the key unit operation for any chloride flowsheet, and discusses in general the advantages of the chloride approach. Several recently-developed flowsheets, which have been tested at the miniplant level, are presented for gold, base metals, titaniferous magnetites and lead-silver ores wherein the advantages of considering a chloride approach are highlighted.

Jan 1, 2014

By H. A. Oliveira, A. Azevedo

Physical and chemical characterization and solid/liquid separation of turbid waters from a river affected by an iron tailing rupture disaster (Gualaxo do Norte River, Brazil) were studied at bench scale. Parameters such as turbidity, pH, surface tension, electrical conductivity, total suspended solids (TSS), particle size distribution (micro- and nanoparticles), and zeta potential were analyzed from samples collected at three different river depths. The results in all samples showed the presence of micro- and nanoparticles, ranging in diameters from 100 nm to 200 μm. Best results for flocculation and settling were obtained at pH 7.5, through an innovative combination of eco-friendly reagents: (i) ferric hydroxide precipitates (10 mg L−1 Fe3+) to sweep (enmesh) the dispersed solids and (ii) gelatinized starch (5 mg L−1 ) to form large flocs. The results showed removals between 90 and 100% of total suspended solids (micro- and nanoparticles), resulting in clear water with residual turbidity < 7 NTU. It is believed that this innovative alternative has a high potential for flocculating and treating the turbid water at Gualaxo do Norte River, assisting the water treatment stations.

By Z. J. Fink

Ultraviolet-visible and infrared emission spectra from propagating methane-coal-dust-inhibitor mixtures have been obtained in a 0.2-by 0.2¬by 5.3-m vertical duct over a range of flame speeds from 2 to 100 m/sec. Results serve as a basis for the design and evaluation of thermal radiation detectors for triggered barriers that suppress ongoing mine explosions. Of particular significance is the large continua superimposed on the methane-air spectra when small amounts of coal dust are present and the variation of emissivity with infrared (IR) wavelength in dust flames. In conjunction with the spectral measurements, studies of flame speed, particle size, gas sampling plus thermodynamics, and dust sampling are presented and discussed in order to gain insight into the more fundamental aspects of propagating explosions. Sampling results have shown that only a near-stoichiometric amount of dust is consumed in the flames studied even though initial concentrations are five times stoichiometric. Difficulty in propagating coal-dust inhibitor flames of realistic mine characteristics in a cold-walled laboratory duct has been encountered. A simplified analysis of the flame zone utilizing spectral and sampling results indicates that the stability of slowly propagating flames is more dependent upon thermal radiation than upon convection losses to the walls. It is predicted that thermal radiation losses will make any measurements of coal dust burning velocities, "quenching diameters," or flammability limits more apparatus dependent than those corresponding to gaseous fuels.

Jan 1, 1974

By Bhaskar B. Thapa

The design of the Caldecott 4th Bore, located along State Route 24 in Oakland, California, is based on the principles of the New Austrian Tunneling Method (NATM). Typical NATM initial support design practices used in Europe were adapted for this project to account for U.S. conditions and requirements, such as degree of experience with NATM construction, the prevailing contractual environment, and preferences for contractual simplicity. Key design features are: (1) support selection criteria based on ground behaviors and ground conditions; (2) a prescriptive design with allowance for support adjustments based on observations during construction; and (3) organization of support requirements into only four major support categories, while permitting some adjustment for variations in ground behaviors and conditions using a few subtypes and additional support measures.

By W. M. Jansen

In many mineral processing operations, the reported production figures for an accounting period may not make the best use of available data. While most of the mathematical approaches, such as check-in/check-out, mass balancing, used in effective metallurgical accounting strategies are well understood, the sources and magnitude of measurement errors generally are not. As part of the &apos;AMIRA P754-Metal Accounting and Reconciliation&apos; project, a study was undertaken at the Northparkes copper/gold concentrator near Parkes, New South Wales to examine the data used in their concentrator metallurgical accounting system. This paper summarises the results of a detailed examination of the mass measurement systems around the concentrator as well as the primary sampling system used for grade estimation. The goal of this work was to develop practical techniques to quantify the error (ie both accuracy and precision) of the measured metal accounting information. With this information, statistical confidence levels for this data can then be calculated. If the errors are small, the effect of error in each piece of measured data can then be propagated to other calculated production figures such as recovery and feed grade using a statistical technique called `the propagation of error&apos;.

Jan 1, 2007

By Alastair C. Torrance

"A brief review of the Australian mining industry is given followed by a more detailed treatment of a study of the influence of primer Size on explosive performance. This is based on a joint research programme conducted by BHP Central Research Laboratories and Dyno Wesfarmers Ltd and examined the effect of the size of cast primers on the run up and steady state detonation velocitiesof ammonium nitrate based explosives as a function of blasthole diameter. The field trials examined a numter of the Dynamo 'Westfarmers HDF series of primers in conjunction with ANFO, emulsion and watergel explosives. Results indicate that the iun up velocity of 187 mm diameter ANFO charges is negligible using cast primers as small as 150g. However, emulsion and watergel explosives did exhibit run up in both 187 and 3:1mm diameter blastholes, independent of the size of primer. This could last from 7 to 10 blashole diameters"

Jan 1, 1991

By Stephen C. Tadolini, Steve Bessinger, James Pile, Christopher Mark

The San Juan Coal Mine, located near Farmington, New Mexico, supplies the San Juan Generating Station with more than 6 million tons of coal annually. To replace dwindling surface mine production, San Juan installed a longwall in 2002. The roof rock in much of the underground reserve consists of interbedded coals, carbonaceous shales, and mudstones. Roof support consists of fully-grouted roof bolts, both tensioned and non-tensioned, supplemented by modified cable trusses. Short-encapsulation pull tests conducted by San Juan’s geotechnical engineering department showed that some of the immediate roof layers provided variable bolt anchorage. To ensure that the roof bolts were obtaining the necessary anchorage, additional tests were conducted in a variety of locations. The results have been used to determine the optimum support design for different areas of the mine. Another series of tests evaluated the performance of several bolt and hole diameter combinations. The experience at San Juan Mine shows that short-encapsulation pull tests can provide the information necessary to improve ground control in variable roof conditions. It also illustrates how a pro-active geotechnical engineering program can be an essential component of a state of the art underground coal mine.

By T. Iwasaki

This paper points out two key elements in resource trade in general and the Canada-Japan relationship in particular. The first is that the advanced countries have a more important role than one would expect in the supply of resources in world trade. Canada &apos;s dual role as a major resource supplier in conjunction with an advanced economy will continue to increase. The second point is the heavy reliance on foreign resource supplies in some advanced economies, particularly in Japan. Finally, as regard the future of the Canada-Japan economic relationship, particularly .in resource development, it is suggested that trade could be enhanced by an accelerated exchange of various types of resources between the two countries. These include natural resource commodities as well as the more abstract capital, technological and human resources.

Jan 1, 1978

By Klaus Rieker

North of Antwerp central train station, two single-track tunnels for the high-speed train line between Brussels and Amsterdam were constructed. At the same time, the central train station was modified to a through station. Both 1.23 km tunnels are situated in the Antwerp sands and were constructed using a slurry shield machine. Due to the inner city location, the tunnels run over their entire length underneath structures, in some cases with only minimal clearance. The paper deals with these challenging situations. In addition, the tunnel boring machine, the tunnel lining and measures to limit settlements will be introduced.

Jan 1, 2007

By Francis J. Arland

The installation of augered cast-in-place (ACIP) piles requires careful quality control to assure a successful pile installation. Unlike steel, pre-stressed concrete or other types of driven piles, which are shop fabricated, delivered to the site and typically driven to a minimum tip resistance, augered cast-in-place piles are installed to a pre-determined tip elevation or to a refusal criteria. The structural section of the ACIP pile is constructed during pile installation and cannot be inspected prior to installation. Therefore, a carefully administered quality control program is essential to a pile foundation that will meet or exceed design requirements. This requires an experienced team consisting of the Geotechnical Engineer, Contractor and Inspector. The focus of this paper is to discuss the responsibilities and duties of the ACIP piling Inspector. Qualifications of the Inspector The qualifications of the inspector are related to the complexity and difficulty of the proposed project. Ideally, the Inspector should be an individual with a degree in civil engineering with special emphasis in geotechnical engineering. A properly trained technician with geotechnical engineering experience working under the direct supervision of a geotechnical engineer may be able to provide competent inspection on some projects. It is important that the Inspector have a good understanding of subsurface and ground water conditions and how they will affect pile installation. The Inspector must understand ACIP pile installation procedures and be able to communicate with the Contractor, Structural and Geotechnical Engineers; and maintain a detailed pile record for each installed pile.

Jan 1, 1997

By H. A. Oliveira, A. Azevedo

Physical and chemical characterization and solid/liquid separation of turbid waters from a river affected by an iron tailing rupture disaster (Gualaxo do Norte River, Brazil) were studied at bench scale. Parameters such as turbidity, pH, surface tension, electrical conductivity, total suspended solids (TSS), particle size distribution (micro- and nanoparticles), and zeta potential were analyzed from samples collected at three different river depths. The results in all samples showed the presence of micro- and nanoparticles, ranging in diameters from 100 nm to 200 μm. Best results for flocculation and settling were obtained at pH 7.5, through an innovative combination of eco-friendly reagents: (i) ferric hydroxide precipitates (10 mg L−1 Fe3+) to sweep (enmesh) the dispersed solids and (ii) gelatinized starch (5 mg L−1 ) to form large flocs. The results showed removals between 90 and 100% of total suspended solids (micro- and nanoparticles), resulting in clear water with residual turbidity < 7 NTU. It is believed that this innovative alternative has a high potential for flocculating and treating the turbid water at Gualaxo do Norte River, assisting the water treatment stations.