Search Documents

Commercial or potentially commercial deposits of coal occur in Australia in strata ranging in age from Permian to Tertiary. The coals of each period tend to show a community of petrographic character and significant differences as compared with coals of other ages. In particular- many of the Permian coals are unusually rich in inertinite whereas the Jurassic and Tertiary coals are typically very rich in vitrinite. The majority of the coals show evidence of deposition in environments subject to relatively minor marine influence. Except for some Tertiary and Permian coals the content of mineral matter tends to be high. Outcrops of coals of bituminous rank appear to be largely restricted to the eastern margin of the Australian continent. In this region vertical rank gradients are generally higher than in the other sedimentary basins and uplift and the removal of cover has occurred to a greater extent. To the west of the Tasman geosyncline, coal of bituminous rank generally occurs at considerable depths (usually in excess of 1 km and in some areas only at depths of over 2 kms), and in most areas coals at shallow depth are of sub-bituminous or brown coal rank. The controls of the distribution of coal type and rank have considerable economic significance and the unusual characteristics of Australian coals, especially with respect to coal type, make the direct application of overseas technology to Australian coals inappropriate.

Jan 1, 1975

By R. W. Raymond

In connection with the discussion of the paper of Mr. James Gayley, presented at the Baltimore meeting, in February, 1892, on " The Preservation of the Hearth and Bosh-walls of the Blast-furnace,"* I offered a translation of a letter received from our distinguished honorary member, Professor P. Ritter von Tunner, concerning the use of carbon-bricks at the Donawitz furnace, then (February, 1892) in the third month of its campaign. The purpose of this brief paper is to put upon record later results of practice with carbon-bricks, both in this country and abroad.

Jan 1, 1897

By W. H. B. Blackburn, D. M. S. Bhatia

Twenty-six in situ analyses of cubic galena crystals from a Mississippi Valley-type deposit were undertaken with a laser microprobe emission spectrograph to study the variation of nine trace elements from the crystal center to its periphery, both along the diagonal and vertical. The general trend is an outward increase in the concentrations of Ag, Ga, Ge and In, with As showing the opposite trend. Bi, Cd and Sn showed no discernable trends. Sb was not detected. These variation patterns may serve as a model for similar studies of other Mississippi Valley-type deposits.

Jan 1, 1987

By Kari Niiranen, Andreas Boehm

LKAB (Luossavaara-Kiirunavaara AB) is operating underground iron ore mine, with three beneficiation and pelletizing plants in Kiruna, Northern Sweden. The wet low intensity magnetic separation (WLIMS) is regarded as the crucial part of silicate mineral separation from the ore. The Kiirunavaara iron ore deposit shows a rather low content of silica (ca. 2.3 to 3.3 % SiO2) but the silica grade is expected to increase in the deeper parts of the deposit. This can be problematic in the case of DR pellet quality with an average silica grade under 0.75 % SiO2. A laboratory scale methodology was developed for the systematic characterization of the ore for mineral processing with the focus on silicates at the Institute of Mineral Processing, University of Leoben. This methodology is combining mineralogical, geochemical and process mineralogical characteristics. Automated mineralogy (QEMSCAN) was used to study the modal mineralogy, the distribution of silicate minerals in different particle size classes after comminution, the deportment of silicon (Si) between various silicates and degree of liberation and intergrowth of magnetite and silicates. Based on the mineralogical investigations, actinolite, phlogopite and even quartz and albite are the predominating SiO2 bearing minerals in the ore. The important result of the investigations was the discovery of two separate subtypes within the high silica ore type B2 based on their mineralogy and mineral processing characteristics. The crucial part of the investigations of intergrowths and liberation of magnetite results was the magnetic separation tests carried out with the Davis magnetic tube. The binary intergrowths of magnetite and the silicate minerals (mostly actinolite) are the most common type of mineral association discovered. The significant characteristics in the intergrowths of magnetite and actinolite are the fine-grained magnetite inclusions in actinolite which may end up increasing the SiO2 grade in the magnetite concentrate despite magnetic separation.

Jan 1, 2016

By Jeffery L. Kohler, Harvinder Singh, Jon G. Bredeson

A survey of electromagnetic noise reports was performed and a summary of the results are given. Industrial concerns were surveyed for techniques to minimize the effects of electromagnetic noise and are presented. The common types of communication links used in mines today are presented. A mathematical development was presented which determines the probability of bit errors versus distance for various types of communication links designed for in mine use. The probability of undetected errors for the protocols of the communication links is given together with burst error detection.

Jan 2, 1981

By Hong Yong Sohn

On the occasion of this symposium in my name, I reflect upon the contributions of my academic mentors and early associates who helped shape my professional career. I was fortunate to have these people around me during my graduate work and at the start of my professional career. In forming my view of the technical field and career, they represented academia, research institutions, industry, and different parts of the world.

Jan 1, 2006

By J. P. Hammond, C. J. McHargue

THERE have been no publications on the wire texture, on the cold-rolled sheet texture, nor on the recrystallized sheet texture of vanadium. Since it has a body-centered cubic structure, it would be expected to show strongly preferred orientations such as are found in iron' and molybdenum.' The wire textures of body-centered cubic iron,3 tungsten," molybdenum,5 antalum,6 iobium,6 and brass6 have been found to have [110] directions lying parallel to the wire axis. Wires of iron,' containing 1.95 pct V or 1.95 pct Si,7 and steel8 retain their texture upon recrystallization. Molybdenum9 and tungsttln' wires retain their texture after recrystallization at low temperatures. A [loo] recrystallization texture has been reported for mo1ybdenum9 and for a Fe-Ni alloy (53 atomic pct Ni).10 The cold-rolled sheet texture for iron,' mild steel," and molybdenum chiefly one in which the [110] directions lie parallel to the rolling direction and the (100) planes lie parallel to the rolling plane with a deviation from this position chiefly about the rolling direction as an axis. This paper presents the cold-rolled and the re-crystallized wire textures, and the cold-rolled and the recrystallized sheet textures for vanadium. The results show that the textures in vanadium are not significantly different from those reported for other body-centered cubic metals. The vanadium used in this investigation was the so-called "ductile" vanadium which has a nominal composition within the following limits:12 0, 0.05 to 0.12 pct; H, 0.001 to 0.004; N, 0.02 to 0.04; C, 0.03 to 0.07; and V, 99.8 to 99.9. The wires were formed by rolling annealed rods of 0.280 in. diam to 0.028 in., a reduction in diameter of 90 pct. The wires were then electrolytically etched to 0.005 in. diam and used as such for specimens. Annealed sheet was reduced 95 pct in thickness from 0.100 to 0.005 in. with a two-high, 4-in. diam mill using reductions no greater than 10 pct per pass. In order to avoid temperature effects, the sheet was allowed to cool between passes. X-ray specimens were made in the form of posts from the sheet. The sheet was mounted in a fixture and the edges were polished using metallographic technique. Each edge was alternately polished and etched during the last stages in order that all worked material would be removed. These post specimens were approximately square in cross-section. The specimens to be recrystallized were wrapped in tantalum foil, sealed in evacuated quartz tubes, and annealed at 1600°F. The X-ray data were obtained from transmission shots made with a 0.030 in. pinhole camera, and molybdenum radiation with a zirconium filter inserted between the specimen and film. The grain size was sufficiently small in both the cold-worked and recrystallized material to give satisfactory results with the specimens stationary. In order for the wire texture to be determined, transmission X-ray patterns were taken with the

Jan 1, 1953

By Colin J. Booth

Hydrogeological impacts of active longwall mining were studied at two sites in Illinois. At the site with the more transmissive sandstone aquifer, aquifer permeabilities increased an order of magnitude due to subsidence. Piezometric levels declined with subsidence due to increased porosity, and ahead of mining due to a transmitted drawdown. Levels recovered rapidly at first and fully over two years. At the site with the less transmissive aquifer, impacts were similar except that recovery has been limited. Local aquifer enhancement through increased yield can occur, but only where the aquifer is transmissive enough for recovery.

Jan 1, 1986

By Mark S. Stagg, Stephen A. Rholl

The U.S. Bureau of Mines has developed computer software which uses fast Fourier transform (FFT) techniques to evaluate blasting data. The software is useful because it allows blasters to evaluate 1) the frequency content of ground vibration time history data; 2) the effects of initiator scatter on the frequency spectra of ground vibrations; and 3) the fragmentation distribution of rock muckpiles from photographs. A one-dimensional version of the software was used in the first two cases. Monte Carlo techniques were used to simulate the scatter of initiators.

Jan 1, 1995

By Beeforth C. G

The use of Non-Linear Programming to obtain improved schedules of future activity in two specific cases of mining and treatment of minerals is described. The two cases were (i) reclamation of gold, uranium and sulphur from old surface tailings dams and, (ii) underground mining of gold. The method used an augmented Lagrangian device to reduce a constrained Non-Linear Programme to a sequence of unconstrained hill- climbing procedures. The main advantages of the method appear to be those of (a)flexibility of modelling of industrial characteristics and constraints and, (b) reasonably modest computation times.

Jan 1, 1977

By Robert F. Holub

The Bureau of Mines has made a study of the magnitude of the variations of radon daughter mixtures, with the objective of determining whether these variations reflect the existing physical conditions in uranium mine atmospheres or if they are merely random or systematic errors. To accomplish this, many data have been plotted using a triangular graphing technique which shows that plateout affects RaA more than RaB or RaC, and that it is impossible to find simple correlations between working level ratios, radon daughter mixtures, and age.

Jan 1, 1978

?Hydrothermal breccias-genetic models ?Deep drilling-underground potential ?Deposit variety-test new ideas Exploration Summary

May 1, 2006

By A. Mertzanis

The way and methods used for the surface mining of bauxite until the end of the twentieth century in the area of Ghiona, resulted in a significant burden to the natural environment, especially in the cases where it covered extended parts of forests and forest areas as well as important geomorphological formations. The impacts from the surface mining of bauxite which in fact constitute the object of this study relate mainly to the interruption of the natural continuity of the land relief and the alteration of the natural geomorphological activities and are due to: a) the alternating excavations with fronts of great heights, b) the depositions of large volumes of waste materials which originate from the revealing of the ore and c) the dense road network constructed in order to get access to the mine locations.

Jan 1, 2006

By Dickinson C.

Discussion at the The Midland Counties Institution of Engineers' general meeting held in Nottingham on 6th May 1916, on the paper published in Trans. I.Min.E., vol.XLVIII, 1914, p.400, included brief oral contributions by Bragge G.S. and Hepplewhite W.H. with the author's responses regarding leakage and boring of cement into the coal

Dec 1, 1916

By Alexander May

In this Bureau of Mines publication stability constants for complexes of diethylenetriamine, 2-aminoethyl sulfide, triethylenetetramine, and 1,8-diamino-3,6-dithiaoctane with copper, nickel, zinc, and cadmium were deter-mined. The amine complexes were found to be much more stable than the analogous thio complexes. The results are interpreted in terms of possible molecular structure of the complexes.

Jan 1, 1974

By Matthew Meyer, Rosa Castro-krawiec, Charles Bartlett

The PortMiami Tunnel project stands as an engineering milestone in Florida, marking the first large-diameter tunnel designed and constructed in the state. As we celebrate Deep Founda- tions Institute's 50th anniversary, it's apropos to revisit this groundbreaking work, first documented by Matthew Meyer, P.E., Rosa Castro-Krawiec, P.E., and Charles Bartlett, P.E., in the January-February 2012 edition of Deep Foundations magazine. Their account details the project's formidable chal- lenges and the innovative solutions that led to its success. Completed in 2014, the PortMiami Tunnel project was a monumental undertaking to alleviate commercial traffic congestion in Downtown Miami. The tunnel links the interstate high- way network to PortMiami in Biscayne Bay, easing city traffic while boosting cargo and cruise ship capacity. This project was not just a feat of engineer- ing but a catalyst for economic growth and regional development. One of the project's most remark- able aspects was its pioneering use of advanced ground improvement tech- niques, particularly deep soil mixing (DSM) for support of excavation (SOE) and groundwater control. Miami's geotechnical conditions presented a unique set of challenges, including highly permeable subsurface materials and high static groundwater levels. Traditional excavation methods were deemed too risky and costly, necessi- tating creative solutions. To launch and retrieve the 40 ft (12 m) diameter tunnel boring machine that was required to construct the tunnel, the project team opted for cutter-soil-mix walls with embedded.

Jan 1, 2012

By Alan D. Fisher

Amtrak made a decision to replace an aging bascule bridge with a vertical lift bridge for their crossing of the Thames River in New London, Connecticut. The new lift bridge occupies the same alignment and shares the same foundations as the bascule span. During construction the deep foundation caisson supporting the bascule span settled and tilted. Investigation into possible reasons revealed interesting historical facts, both of the construction of the innovative open well caisson foundations and of the state-of-the-art in tremie concrete placing methods in use at the turn of the century. This paper describes both of these topics.

Jan 1, 2013

By W. A. Tiller, J. P. McHugh

THE phase diagram of the Ge-Te system was first investigated by Klemm and Frischmuth.' They arrived at the phase diagram shown in Fig. 1 indicating the presence of a peritectic phase boundary at the 50 at. pct Ge composition. Later, Schubert and Fricke2 obtained data which suggested to them the possible existence of a eutectic at about 55 at. pct Ge. In order to resolve these differences, we have carefully studied this system in the region 40 to 60 at. pct Ge using both the conventional thermal analysis technique and a new solidification technique.3y4 The alloys were prepared from semiconductor grade germanium and 99.999+ Te by reacting the elements in evacuated, graphite coated, vycor tubes. The samples were placed in a thermal analysis apparatus described elsewhere4 and cooling curves were taken of each alloy to determine the liquidus surface. The cooling curve for a 50 at. pct alloy shows two distinct arrests about 1°C apart which

Jan 1, 1961

By Sterry Hunt

The American Institute of Mining Engineers, and American science in general, have sustained a great loss in the death of Prof Benjamin Silliman, deceased at New Haven, Connecticut, on the 14th of January, 1885, at the age of sixty-eight. But a month has passed since, as one of the pall-bearers, I paid the last tribute to the remains of my old friend and honored master.

Jan 1, 1885

Concrete has been used for many years in block caving, principally for drift and drawpoint linings. This paper describes the requirements for concrete in this application, the required properties, the mix design, and transportation and placement systems. In addition a concrete mix design rationale is also proposed.

Jan 1, 2000