Search Documents

Executive SIDNEY J. JENNINGS, Chairman GEORGE D. BARRON J. E. JOHNSON, JR. EDWIN LUDLOW ROBERT-M. RAYMOND Membership LEWIS W. FRANCIS KARL EILERS, Chairman J. E. JOHNSON, JR. LOUIS D. HUNTOON ARTHUR L. WALKER Finance GEORGE D. BARRON, Chairman CHARLES F. RAND BENJAMIN B. THAYER Library E. GYBBON SPILSBURY.1 Chairman. ALEX C. HUMPHREYS3 GEORGE C. STONE2 J. H. JANEWAY4 BRADLEY STOUGHTON Papers and Publications BRADLEY STOUGHTON, Chairman

Jan 2, 1919

Executive SIDNEY J. JENNINGS, Chairman GEORGE D. BARRON J. E. JOHNSON, JR. EDWIN LUDLOW ROBERT M. RAYMOND Membership KARL EILERS, Chairman LEWIS W. FRANCIS J. E. JOHNSON, JR. LOUIS D. HUNTOON ARTHUR L. WALKER Finance GEORGE D. BARRON, Chairman CHARLES F. RAND BENJAMIN B. THAYER Library E. GYBBON SPILSBURY,1 Chairman ALEX C. HUMPHREYS3 GEORGE C.' STONE2 J. H. JANEWAY4 BRADLEY, STOUGHTON Papers and Publications BRADLEY STOUGHTON, Chairman

Jan 7, 1918

WILLIAM L SAUNDERS, President GEORGE H PEGRAM, 1st Vice-president ALFRED D FLINN, Secretary J V W REYNDERS, 2d Vice-president JACOBS LANGTHORN, Treasurer HENRY A LARDNER Assistant treasurer Finance Committee House Committee GEORGE H PEGRAM, Chairman ; ALFRED D FLINN. Chairman J VIPOND DAVIES FREDERICK F SHARPLESS BANCROFT GHERARDI JOHN H DUNLAP WILLIAM L SAUNDERS CALVIN W RICE W F M GOSS, ex-officio F L HUTCHINSON

Jan 1, 1923

By Sohta Takatsu, Hachiroh Mizubata, Shigeki Kudoh, Kazuya Takekuni, Yoshinori Yamada

A special type of shotcrete is used to improve the performance of open-type TBM in difficult situations. The Hakamagoshi and Johana tunnels are expressway evacuation tunnels of 3.2 km and 5.1 km in length, respectively (total 9.1 km) that were excavated by one open-type TBM. The geological conditions at the sites were estimated to be good before excavation. However, 95% of the rock turned out to be two ranking orders worse than the estimated classes. Therefore, we used a special shotcrete for bad rock conditions, and succeeded in excavating the tunnel at an average rate of 270 m/month.

Jan 1, 2001

By R. N. Tempel, M. Lengke

Arsenic sulfide [orpiment, realgar, amorphous AsS and As2S3] oxidation rates were measured in mixed flow reactors at pH~2 and temperature of 25-30oC. The measured oxidation rates for arsenic sulfide solids by dissolved oxygen are in the range of 10-11 to 10-10 mole m-2 s-1 after being normalized to final surface area. The order of arsenic sulfide oxidation rates decreases at pH~2 from amorphous AsS > realgar > orpiment > amorphous As2S3. In comparison to pyrite, arsenic sulfide oxidation rates are approximately 1.5 to 15 times slower than pyrite oxidation rates at pH~2.

Jan 1, 2002

By E. J. Berentsen

The Turquoise Ridge gold deposit is located near the Getchell Mine, 72 km (42 miles)northeast of Winnemucca, NV (Fig. 1). The deposit is owned by Getchell Gold Corp. The host rocks consist of Ordovician and Cambrian age shales and limestones. They have been crosscut by the northeast-trending Turquoise Ridge shear zone and northwest-trending shear zones. Gold mineralization occurs at depths from 427 to 671 m (1,400to 2,200 ft) along the intersection of these structures. Large tonnage, flat-lying deposits occur where folded, favorable beds are intersected by the faults. The carbonate in the beds has been replaced with silica, pyrite and arsenic sulfides.

Jan 1, 1996

By Jacob L. Mathis, Todd Tharpe, Jonathan Steflik, R. M. True

In June 2022, Louisville MSD completed a 6.5 km (4-mile), 6.1 m (20-foot) finisheddiameter CSO conveyance and storage tunnel system located along the Ohio River in downtown Louisville, Kentucky. During construction, the Ohio River Tunnel alignment was expanded 2.4 km (1.5 miles) into areas where natural gas was detected. Without delaying construction, the project team developed and implemented a natural gas risk mitigation strategy to safely excavate the tunnel via TBM and install concrete lining. The risk mitigation strategy included the installation of gas-vent borings, increased tunnel ventilation, retrofitting tunneling equipment for “gassy” operations, and modifying the project specific HASP.

Jun 13, 2023

By I. S. Parrish, D. W. Kappes, G. G. Austin

Micron-sized gold disseminated in lower Cambrian siltstone has been found at the Sterling mine near Beatty, NV. A shoestring-shaped body has been developed by central and fringe drifts and is being mined via a modified retreat room and pillar system. The siliceous ore crushed to 5.08 cm (2 in ) is stacked to 4.6 m (15 ft) over a layered sand, gravel, and impervious PVC base. Gold is leached using a 0.1% cyanide solution and deposited on activated coconut shell carbon. Stripping of the carbon by hot solutions of 1% NaOH and 20% Ethanol yields overall recovery of about 75% of the fire assay head.

Jan 1, 1983

By R. G. Johnson

The prevailing system of locating wells on a rectangular basis, as shown in Fig. 1-A, has developed because of the exigencies of offsetting at boundary lines. When, however, a very large tract is being drilled, it is often possible to abandon this inferior method for the superior arrange- ment known as "staggering," which is illustrated in Fig. 1, B and C. The advantages of the triangular over the rectangular method are evident from Fig. 2, computed on the basis of one well to 10 acres (4 ha.). With the triangular system, no land is more than 409.4 ft. (124.8 m.) from a

Jan 1, 1920

By Tomoji Kawai

"The Pulsed Laser Deposition method using multi-targets is extremely useful for the creation of functional multi-layers and variety of artificial lattices. The topic of the present talk is on the creation of ''Function hannonized artificial lattices by laser ablation"" made of the combined magnetic, ferroelectiric and superconducting layers. The outline of talk is,1. Features of Pulsed Laser Deposition method (Laser Molecular RHEED and S1M/AFM.2. Creation of magnetic, dielectric and superconducting artificial lattices by Pulsed Laser Deposition.3. Novel properties of function harmonized artificial lattices: especially on the magnetic and magnetoresistive artificial The outline of talk is, lattices made of3d transition metal oxides."

Jan 1, 2000

By R M. Briggs, I E. Smith, P M. Black, A B, R L. Brathwaite, J L. Mauk

The Hauraki Volcanic Region of the North Island developed between 18 and 1.9 Ma. Initial andesitic volcanism from 18 to 12 Ma was followed by 12 to 1.9 Ma volcanic activity that included rhyolitic, dacitic, andesitic, and basaltic compositions, with a gradual migration of activity to the SSE. Early andesitic volcanism evolved over the course of 8 m.y. to more silicic compositions; this trend was reset and repeated by post-10 Ma andesitic volcanism. Early and later andesites are otherwise remarkably similar in trace element composition. Rhyolites have the most diverse compositions, suggesting a major role for crustal input in their formation.

Jan 1, 2007

By C Riley, N Davies, J Carpenter, I Lipton

Nautilus Minerals Incorporated (Nautilus) recently announced the worldÆs first Seafloor Massive Sulfide Mineral Resource at Solwara 1 in the Bismarck Sea, Papua New Guinea . The discovery, exploration and resource modelling of this æblack smokerÆ system located 1500 m under the sea involved unique technological development. Whilst the resource estimation methodology had similarities with approaches adopted for analogous volcanic-hosted massive sulfide (VHMS) deposits, specific parts of the resource estimate called for new ways of assessing data. This paper discusses several innovative methods for collecting and assessing Solwara 1 exploration data. This ia an ABSTRACT only. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By R. N. Tempel, M. Lengke

Arsenic sulfide (orpiment, realgar, amorphous AsS and As2S3) oxidation rates were measured in mixed flow reactors at pH-2 and at temperatures of 25 ° to 30 °C. The measured oxidation rates for arsenic sulfide solids by dissolved oxygen are in the range of 10-11 to 10-10 mole m-2s-1 after being normalized to final surface area. The order of arsenic sulfide oxidation rates decreases at pH-2 from amorphous AsS > realgar > orpiment > amorphous As2S3. Compared to pyrite, arsenic sulfide oxidation rates are approximately 1.5 to 15 times slower than pyrite oxidation rates at pH-2.

Jan 1, 2003

By J. F. Whelan, B. D. Marshall, Z. E. Peterman, J. B. Paces, L. A. Neymark

Observations of calcite and opal in cavities in the unsaturated zone at Yucca Mountain indicate that: 1) seeps are not regularly spaced in underground workings and not all fractures sustain flow, 2) many cavities represent sites of seepage that have remained stable for millions of years, 3) typically there is no evidence (such as dripstone) for seepage dripping into cavities from their ceilings, and 4) seepage is not likely to be greater than about 1 liter of water per year (per 5-m-long drift) based on calcite abundances observed in the ESF. This estimate of seepage is significantly lower than that used for performance assessment.

Jan 1, 2000

For the year ending February, 1920 PRESIDENT HORACE V. WINCHELL.. . MINNEAPOLIS, MINN. PAST PRESIDENTS PHILIP N. MOORE ST. Louis, Mo. SIDNEY J. JENNINGS NEW YORK, N. Y. FIRST VICE-PRESIDENT A. R. LEDOUX NEW YORK, N. Y. TREASURER GEORGE D. BARRON NEW YORK, N. Y SECRETARY BRADLEY STOUGHTON NEW YORK, N. Y VICE-PRESIDENTS CHARLES W. GOODALE,1 . . . . District 5 BUTTE, MONT. MARK L. REQUA,1 District 6 SAN FRANCISCO, CAL. HENRY S. DRINKER, District 2 So. BETHLEHEM, PA. ROBERT M. RAYMOND,2 . . . . District 0 NEW YORK, N. Y. EDWIN LUDLOW,3 District 2 LANSFORD, PA. A. R. LEDOUX,3 District.0 NEW YORK, N. Y.

Jan 11, 1919

By J. A. Morgan, W. A. Barclay, J. C. Pedersen, I. C. Campbell, D. S. Bubar, R. P. Taylor

"Abstract - The Lilypad Lakes property is host to a group of Ta-mineralized dikes that occur over an area of at least 10 km2. Field relationships are consistent with a syn- to late syn-tectonic timing for their emplacement (with respect to the major regional D1 episode of deformation), with several of the dikes exhibiting a steeply dipping, open, S- to M- to Z-shaped fold geometry. Individual dikes range up to 30 m wide (Rubellite Dyke, Pollucite Dyke), have strike lengths of up to 750 m (e.g., JJ Dyke), and are continuous to depths of greater than 250 m (e.g., Rubellite Dyke, Pollucite Dyke). Typically, they display sharp intrusive contacts characterized by the development of thin, holmquistite-rich haloes. The Tamineralized dikes are comprised of silica- and alumina-rich, sodic, granitic pegmatites that display extreme levels of geochemical fractionation (K/Rb typically < 10.0, as low as 2.2; Nb/Ta typically < 0.20, as low as 0.03), and enrichments in an economically important group of lithophile elements, most notably Li, Rb, Cs, and Ta. Geochemical assays of individual surface grab and drill core samples have yielded values as high as 1.51 wt.% Li2O, 1.25 wt.% Rb2O, 6.21 wt.% Cs2O, and 0.108 wt.% Ta2O5. Diamond drilling has established the presence of wide (~20 m), potentially ore-grade intersections of Ta mineralization (>0.045 wt.% Ta2O5) in both the Rubellite and the Pollucite Dykes.Three Ta-oxide minerals (microlite, wodginite, manganotantalite) of primary origin predominate in the Ta-mineralized dikes, where they occur as fine, disseminated grains in the albite-rich pegmatite matrix. The sequence of crystallization is typically manganotantalite wodginite microlite, which conforms to a well-established paragenetic sequence for rare-element granitic pegmatites in general. All three of the primary Ta oxides are characterized by a high degree of chemical purity (e.g., average Ta concentrations in microlite from 77-79 wt.% Ta2O5), a compositional feature consistent with the extreme levels of geochemical fractionation characteristic of the host granitic pegmatites, and one that indicates that the Lilypad Lakes pegmatites are likely to produce Ta mineral concentrates of the very highest quality.Locally, a second generation of Ta minerals is present, restricted to small vugs in the pegmatite matrix that are surrounded by fine aggregates of K-rich mica or clay. The secondary Ta minerals are dominated by microlite, which is typically intergrown with fluorite and Fe-sulphides, and is distinguished from its primary counterpart by its lower Ta content (around 70 wt.% Ta2O5) and much higher concentration of uranium (up to 9 wt.% UO2). Also, secondary microlite consistently yields low analytical totals from electron microprobe analysis, suggesting that it is H2O-rich. The presence of this second, vug-related generation of microlite, together with the occurrence of localized networks of crosscutting fractures that host high concentrations of Cs and Rb (in the minerals pollucite and Rb-Kfeldspar), suggests that a late-stage, fluid-dominated metasomatic/hydrothermal event may have been important in certain sections of the dikes, and has effected a redistribution of the economically important elements Ta and Cs."

Jan 1, 2005

By Roger Malmström, H. Heden, Kjell Lidin

INTRODUCTION LKAB was formed at the turn of the century when the railways between the ore fields and harbors were built. The mines are situated north of the Arctic Circle in Sweden. Kiirunavaara is the largest mine, with a pro¬duction capacity of approximately 30 Mt/a. Malm¬berget has a capacity of about 12 Mt/ a. Both are under¬ground mines. Svappavaara, the only opencast mine currently in operation, has a capacity of about 4.5 Mt/a. The ore harbors are at Narvik for the Kiruna and Svappavaara mines and at Lulea for the Malmberget mine (see Fig. 1). Production in the form of finished products is shown in Fig. 2a, b, c, and d. Due to poor ore markets in re¬cent years, production and shipments have been cut back, but there was a positive swing in 1978. LKAB has been 96% state-owned since 1957. In addition to the iron mines in northern Sweden, LKAB has subsidiaries in central Sweden which produce sulfide ores, quartz sand, and uranium (Fig. 3). The mining methods employed are opencast bench stoping at Svappavaara and sublevel caving at Kiirunavaara and Malmberget. GEOLOGY The Kiirunavaara ore body is 4000 m long and av¬erages about 90 m wide, with variations in width from a few meters to around 150 m. The ore has been ex¬plored by deep drilling down to about 1000 m, but mag¬netic measurements indicate a depth of at least 1500 m. The Kiirunavaara ore is oriented in a north-northeasterly direction with a number of ores in the boundaries be¬tween the wall rock types. The ore in Kiirunavaara is mainly a fine-grained magnetite with a varying content of fine-grained apatite. The apatite content of the ore decreases with increasing depth. The other ores are all apatite-bearing and a couple are hematite ores (Fig. 4a, b). The ores are sedimentary, tilted, and tectonically de¬formed. They have a lateral dip of 0.87 to 1.2 rad (50 to 70°). The contacts between ore and wall rock are distinct and sharp, but both the hanging wall and the footwall are brecciated and impregnated with magnetite. The footwall of the Kiirunavaara ore consists of syenite porphyry with a low quartz content and rela¬tively good strength; the hanging wall consists of quartz porphyry. Both types are known as Kiruna porphyries. The ore at the boundary with the hanging wall is often rich in kaolin. There are a few veins of syenite porphyry running through the ore, which has a few major faults (Fig. 4c, d). There are two sharply delineated ore grades in Kiirunavaara: low phosphorus ore with less than 0.1 % phosphorus (about one-third of the ore) and high phos¬phorus ore with greater than 0.5% phosphorus. The iron content is 67% in the low phosphorus ore and 60% in the high phosphorus ore. These ore types are sold as different grades and so are kept separate during mining. MINING AT KIIRUNAVAARA The Kiirunavaara and Luossavaara ores were first mined using opencast bench stoping in 1902. When mining costs rose owing to higher waste removal, under¬ground methods were adopted. In the mid-1950s, the ores were still being mined on the surface at the same

Jan 1, 1982

By Leeming. J. R.

In the UK, powered supports are normally salvaged from longwall faces on completion of production, for reuse on the next unit. Where a spare set of supports are held, the salvaged supports are often stored in underground roadways awaiting installation. One mine in the UK extracts a 5m section, and holds two sets of 2x950t powered supports, each weighing approx. 35t and having closed dimensions of 8m long, 2.5 high and 1.75m wide. As the first set would not be required for over 12 months, and because of space limitations below ground, it was decided that the supports would be left in situ, the district sealed, and reopened at a later date for support salvage. The paper described the decision making process, and the inertisation of the sealed district utilising nitrogen generated on the mine surface and piped to the point of use. The re-entry and re-ventilation of the district are also described. The paper then goes on to describe in more detail the discovery of a spontaneous combustion event that occurred in the waste behind the powered supports, and its treatment and control using extra nitrogen brought to the mine by tanker and introduced at strategic locations along the faceline via boreholes, leading to a successful salvage and re-sealing.

Jan 1, 2009

By Clive Chadbourne

Investigations of world wide coal face strata control practice, the study of theoretical calculations and detailed engineering analysis have been combined to design and select a powered roof support suitable for use in conjunction with the extraction of 4.5-m (14.7- ft) of the 7.5-m (24.6-ft) thick Warwickshire Thick Coal Seam. The interface between geotechnical criteria and engineering design has been closely considered along with the following 3 important factors: Firstly, the need to further improve strata control and operational characteristics whilst producing a wall integrated overall face design. Secondly, to enable the supports to be rapidly transported from face to face in roadways driven at the minimum size for operational requirements. Finally, to provide hydraulic power, automatic control and monitoring systems which will improve operations reduce manpower requirements and improve management information. Clear design requirements were determined in order to allow selection on a commercial basis. A method of tendering is described with the subsequent analysis and selection process. In the event oversupply of coal in the UK resulted in the order not being placed. Brief consideration has been given to supports suitable for reserves to be mined In a few year&apos;s time where there is potential for extraction well in excess of 4.5-m (1 4.74.

Jan 1, 1994

By A. Deepatana

Bioleaching of nickel laterite ores is based on the use of heterotrophic fungi organisms and their metabolites (organic acids) to dissolve nickel and cobalt from oxide minerals to form metal-organic complexes. Metal recovery from this process using an aminophosphonic acid based chelating resin (Purolite S950) was investigated as a function of metal concentrations, complexing agent including citric, dL-malic and lactic acids. Batch adsorptions were conducted using synthetic leachate solutions of nickel and cobalt with concentrations from 15 to 2000 mg/L prepared in 0.01 and 0.1 M organic acids. Adsorption equilibrium data were interpreted using the Langmuir, Freundlich and Dubinin-Kagner-Radushkevich (DKR) models. The results showed that equilibrium adsorption data for nickel-organic complexes followed the Freundlich model and those for cobalt agreed with the Langmuir model. It was observed that the maximum adsorption capacities of nickel and cobalt were 3.26 and 10.48 mg/g resins respectively. These were achieved in metal complexes prepared from 0.01 M lactic acid. Metal elution was conducted using 2 M nitric acid. High metal recoveries were achieved from low metal concentrations but were found to decrease with increasing metal concentration. The results suggest that effective recovery of nickel and cobalt from low concentration of metals, such as those generated from bioleaching operations, can be achieved suitably using chelating resins.

Jan 1, 2006