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By Chingyuan Y. Li, C. Y. Hsieh

Realizing that aluminum will have a great role to play in the coming industrialization of China, Chinese geologists have long been looking about for some aluminum deposits. The possible sources appear to be alunite, the alumina-rich shales, and the bauxite deposits. The locations of deposits are shown in Fig. I. Alunite Our attention was first directed to the alunite deposits along the southeastern coast of China. Table I summarizes the reserves now believed to exist in that region. Other alunite deposits have been found in Kiangpei, Szechuan province; Charming. Liuyang and Hsanshan, Hunnan province Tsingchow and Chowyuan, Shantung province. No reserve figures are available. High-alumina Shale Shale high enough in aluminum to serve as a source of that metal has been found in northeastern China(Tab1e 2). In Manchuria, the Manchuria Light Metals Co., at Antung and Fushun, operating under Japanese control, has been the only active producer of aluminum. It is not known, however, whether the company uses local raw materials or imports ore from elsewhere.* Shantung Bauxite Bauxite was first recognized in China at Paoshan, Shantung province. Although the reserve is reported to be large (estimated at 271 million tons), the high content of insoluble residue (SiO2) and mineral composition (diaspore) are dis-

Jan 1, 1948

By D. M. S. Bhatia, Richard D. Hagni

Five sulfide minerals from the Magmont mine, southeast Missouri were sampled for 31 trace elements in over 300 samples by laser microprobe spectrographic analysis of polished sections. The concentration of several trace elements shows a pattern of progressive variation with depth (space) and variation with different paragenetic stages (time) of each mineral. Factor analysis of the geochemical data shows sympathetic correlation both in space and in time of Bi, Cd, Ge, and Sn in galena and sphalerite, and Ni and Co in sphalerite and marcasite.

Jan 1, 1981

By T. G. Carnahan

The Bureau of Mines conducted research to simulate in situ leaching of a porphyry copper sulfide ore. The purpose was to determine the effects on copper leaching of additions of NaCI to a conventional sulfate leach system and to analyze the oxidant requirements and the oxidation products that resulted from leaching of the sulfide minerals in the ore. Baseline sulfate and sulfate plus 2-pct-NaCl-leach-solution experiments employing 167-kg (367-lb) and 152-kg (333-lb) charges, respectively, were conducted. The minus 25.4-cm (10-inch) ore was leached at 90° C under flooded conditions with 2.8 MPa (400 psig) of oxygen bubbling through the system. Sixty-seven pct of the copper was extracted in 1,236 days of leaching in the NaCI experiment, whereas 47 pct of the copper was extracted in 913 days of leaching in the baseline experiment. Diffusion into and out of the ore fragments controlled the rate of leaching, which precluded enhancement of the leach rate by the chloride ions. The calculated oxygen consumption was 3.17 kg/kg of copper extracted in the baseline experiment and 3.46 kg/kg of copper extracted in the experiment to determine the effect of chloride ions.

Jan 1, 1982

By Kerry Gee, Gary Colgan, James Fricke

Introduction Elevated zinc concentrations are observed in groundwater within alluvium adjacent to Silver Creek east of Park City, Utah. The study area is located in a small valley one and one-half miles northeast of Park City, Utah in Summit County, Utah (Figure 1). Although surface water concentrations in Silver Creek are typically less than 1 mg/l, groundwater concentrations have been measured as high as 85 mg/l in a near neutral pH environment. The elevated zinc concentrations in groundwater result from several factors including: (1) dissolution of zinc from tailings exposed at the surface and within the alluvium, (2) oxidizing conditions created by surface/ground-water exchange, and (3) ideal geochemical conditions for the dissolution of zinc-containing minerals. These ideal conditions include readily soluble minerals, available anions for complexation, and lack of available surface adsorption sites.

Jan 1, 2005

By C. H. Herty

The results of a study of the open-hearth process from the physicochemical viewpoint are given. This study includes experimentation in small laboratory furnaces and in standard 100-ton furnaces. The behavior of manganese, carbon and phosphorus are quantitatively explained. The action of "residual" manganese is discussed with reference to its relation to iron oxide dissolved in the metal. The solubility of CO in steel and its relation to dissolved FeO and carbon is given. The equation for phosphorus elimination has been tested out on a 200-ton furnace and the results are given in the text. The effect of temperature and slag composition on the elimination of metalloids in the basic open-hearth process has been qualitatively understood since the early days of steel making. The quantitative effect has, however, only recently been brought to attention. The effect of slag composition has received more attention than that of temperature, primarily because the range of finishing temperatures in the basic open-hearth process is small compared to the large variations found in the composition of the slag at different periods during the process, and to the variations occurring with the use of raw materials of different degrees of impurity. The effect of slag composition on the elimination of metalloids has been studied by Styril from the thermochemical standpoint. This method is open to serious errors, in that thermochemical data at 2900' F. are very inaccurate and in many cases completely lacking. Feild2 has calculated equilibrium constants from the rate at which the metalloids are eliminated. The effect of slag viscosity on rate of elimination will affect the constants calculated by this method. Whitely,a Colcough4 and others have used slag compositions as the basis for calculation of constants by which the extent of elimination may be calculated.

Jan 1, 1926

By R. D. Pehlke, J. V. Gluck

The effect of small additions of silver on the actiziity of zinc in dilute solution with molten bismuth has been determined ill the range 450° to 650°C. Experimental measurements were made in a multi-electrode galvanic cell. All zinc activities showed large positive deviations from Raoult's Law. The results are expressed in terms of the interaction parameter EJ, as defined by Wagner. In the binary Zn-Bi system, Henry's Law was followed at zinc concentrations below 5 mol pct, thus indicating that the binary or self-interaction parameter of zinc in bismuth is essentially zero. The Henry's Law con- THE determination of thermodynamic interaction parameters requires accurate knowledge of solute activities in the dilute-solution region. Dealy and Pehlke1 have summarized the basis for interaction relations, discussed some theoretical implications, and presented a compilation of interaction parameters calculated for molten nonferrous alloys from stant ranged from 2.43 at 650°C to 3.96 at 450°C. The binary zinc activities were consistent with published data for higher zinc concentrations . The ternary interaction parameter ranged from -1.90 at 650°C to -3.30 at 450° C, varying linearly with the reciprocal of the absolute temperature. The negative value for the parameter reflects the fact that addition of silver decreases the activity of zinc in solution with bismuth. data available in the literature. Most of the data were for two-component systems from which only the self-interactions, Ei, could be calculated. Concentration ranges were often such that a considerable extrapolation was required for calculations at lnfinite dilution. The data for ternary systems were quite limited and often unavailable in suitable systematic fashion—thus few values of the parameter e| could be obtained. Knowledge of both the binary and ternary interaction parameters is necessary for the estimation of the activity coefficient of a given dilute solute in

Jan 1, 1965

The segment of the Upper Cenozoic volcanic chain (CVZ) located on the western border of South America (16-28¦S lat.) is constituted by an association of strato- volcanoes and ignimbrite sheets, with high K calco-alkaline affinities. Strata-bound volcanoes, mainly of andesitic and dacitic composition, present along the whole chain, and various hydrothermal alteration zones, on the slopes and in the cores of eroded volcanic structures. Some of these altera- tion zones bear epithermal precious metal ores and sulphur deposits, which at present are being exploited. The studied Salar de Gorbea area, located in the Andes of northern Chile (25-26¦S lat.) contains a numer- ous group of Miocene to Quaternary stratovolcanoes, with advanced argillic and extreme silicification hydrothermal alteration in their cores and on their slopes, favoring the formation of great volumes of alunite within altered zones and sulphur deposits in the higher parts of the volcanic edifices. Simultaneously, siliceous hydrothermal breccia of the phreato-magmatic type, with evidences of hydromag- matic explosions are recognizable, allowing, in some cases, the ascent towards the surface of rock fragments belonging to the Paleozoic pre volcanic basement. Radiometric ages obtained in some of the hydro- thermal alteration zones (K-Ar in alunite) are slighty young- er than the unaltered rocks which constitute the strato- volcano. Trace element (Hg, As, Sb, S, Au, Ag, Cu, Pb, Zn, Mo) patterns in orientative rock samplings show that the studied alterations zones correspond to high sectors of the cpithermal system, without evidences of metallic minerali- zation on surface. The weak erosive action due to the ex- tremely and climatic conditions in this segment of the Andes, has not allowed the cropping out of deeper areas of the hydrothermal alteration zones, in contrast to other Miocene more eroded volcanic edifices and Miocene vol- canic terranes of the Andean Range.

Jan 1, 1987

By Rene Rodriguez

The initial results of our investigations on the applicability of geophysical exploration methods to map coal seam inclusions were summarized in a paper submitted at the Thirteenth Conference on Ground Control in Mining in 1994. These investigations were continued under a variety of conditions at a number of underground coal mining operations. The results have been encouraging and have fostered a much more detailed understanding of the geophysical principles at work in underground mine mapping. This report summarizes a particularly interesting application, that is, the use of Underground In-Seam Seismic exploration methods to identify and to approximately delineate coal seam inclusions within longwall panels. The methodology relies on the excitation of seismic sources in the coal seam along one side of the panel and the recording of seismic waves by geophones secured to the coal rib on the opposite side. Head-Body waves (compressional and shear), direct and channel waves are generated in the process. While the head waves are critically refracted waves traveling at the coal floor and roof, direct and channel waves are transmitted through the coal body and are dispersive in character. Tomographic techniques applied to the velocity inversion of first arrivals permits a fast mapping of coal seam inclusions in the panel. The process incorporates path velocity and geostatistical intersect analysis. Full wave analysis of the dispersive channel waves, provides an independent and confirmatory information of the coal geometry, including the inclusions within. The inversion technique in this case is the modal analysis of the wave trains. The application of this method to three different problems was confirmed by subsequent mining of the predicted anomalies, proving the accuracy of the technique within limits of experimental error.

Jan 1, 1995

By J. V. Gluck

In the present paper," as in earlier publications, V1'2"1 the authors present experimentally obtained relations for the free energy of solution of oxygen in various metals as a function of temperature. The relations are linear and given in slope-intercept form. The authors give values for the "probable error" of the slope and intercept, citing Birge's method17 for obtaining these quantities. Birge discussed these methods as early as the period 1929-32.25726 In Ref. 25 the probable error is defined as "the numerical value which the true error is as likely to exceed as not", i.e., 50 pct probability. Ref. 26 is even more detailed and includes a lengthy discussion of the applicability of the Gaussian distribution to experimental data. However, the use of the "probable error" has come under some question. For example, Ezekiel'~ states that "the use of the probable error tends to make the results appear rather more accurate than the standard error". Moroney28 stated (in 1951) that "the term 'probable error' was used in former times to denote 0.67450 (50 pct confidence using the normal distribution)....the term, a poor one, is now very much obsolescent. It has been said that 'it is neither an error nor probable' ". Bennett and Franklin in 1954" in discussing statistical confidence levels mentioned that "the customary use of the 5 and 1 pct levels is not completely a matter of chance; these levels probably represent a balance between the desire to be correct and the desire to be specific. Also in most people's minds the borderline between something that could possibly happen and something that is not likely to happen is somewhere in this region. Certainly 5 or 1 pct confidence limits are to be preferred to limits such as the 'probable error' which has only a 50/50 chance of including the correct value." It may readily be seen that the 95 pct confidence level, which is given by 1.960 (assuming large sample size), thus corresponds to approximately three times the "probable error". Indeed, limits of one standard deviation correspond only to about 68 pct probability. Even if we triple the tolerances given by the authors in the equations of their Table 111, the deviations do not become excessive and would not detract from their excellent results. It could then be said with a high degree of confidence (95%) that the precision of the slope and intercept values is about *3-5 percent of their absolute levels rather than the 1-2 percent implied in Table 111. This is then compatible with an earlier suggestion of Gokcen~' of a probable accuracy of 5 pct in dissolved oxygen measurements by the technique employed. Alternatively, the authors could have

Jan 1, 1967

By J. L. Taylor, P. Duwez

PARTIAL phase diagrams of titanium with iron, cobalt, and nickel have been established by previous investigators.1-3 These diagrams seem to be reliable, at least for concentrations of titanium ranging from 0 to about 50 at. pct. More recently, Long and his collaborators have presented a tentative titanium-nickel diagram covering the titanium-rich side.' These various studies indicate that in each system three intermediate phases exist and correspond to the compositions Tia, TiX, and TiX2 (or TiX3). The purpose of this paper is to review the available information on the crystal structure of these phases and to give the results of additional X-ray diffraction studies. Previous Work A summary of the work of Wallbaum and his collaborators"-' is presented in table I. The first intermediate phase on the titanium-rich side of the three systems, with iron, cobalt, and nickel, is of the Ti2X type and has a face-centered cubic structure. Although it is stated that the unit cell contains 96 atoms: no lattice parameters are given. The second phase is centered around the compositions TiX for the three systems. The crystal structure of this phase is mentioned in a short note" as being body-centered cubic (CsCl type), but no parameters are given. The analogy between the three systems, which is perfect as far as the two phases of the type Ti2X and TiX are concerned, disappears at the titanium-poor end of the diagrams. In the system titanium- iron, TiFe2 has an hexagonal (MgZn2 type) struc-ture with the parameters given in table I. The existence of TiFe3 has also been reported8 (table I) but was questioned by other investigators2 and is also refuted by the present study. In the system titanium-cobalt, a phase corre-sponding to the composition TiCo2 has been investi-gated by Wallbaum and Witte6 who claim that the structure is cubic (MgCu2 type) for alloys slightly deficient in cobalt and hexagonal (MgNi2 type) for alloys slightly deficient in titanium. The parameters of the two phases are given in table I. In the system titanium-nickel, the nickel-rich phase corresponds to the composition TiNi3 and has been described as hexagonal7 with the parameters given in table I. The present investigation was initiated for the purpose of filling in the gaps in the knowledge con-cerning the structure of the various phases sum-marized in table I. Since the titanium used by Wallbaum and his collaborators was only 95 pct pure,' it was found desirable to redetermine the lattice parameters of the alloys prepared with a

Jan 1, 1951

By Robert B. Sosman

The chance that a Howe Memorial Lecturer will be able to refer back to a personal contact with the distinguished metallurgist for whom this lectureship is named grows steadily I I did not have the pleasure of his personal acquaintance, but I did receive from him in 1916, quite unexpectedly, a letter commenting On a paper that I had recently published27 On "Types of Prismatic Structure in Igneous Rocks." The paper was written for geologists and petrologists, but it had an application, naturally, to the crystallization of iron and steel in a mold. The letter impressed me at the time, and still does, with the breadth of of Howe's interests and his perseverance in keeping up with the progress of any branch of knowledge that had metallurgical connotations. Scope of the Lecture During several years preceding the date mentioned I had worked in collaboration with Arthur L. Day and E. T. Allen8 at the Geophysical Laboratory, Carnegie Institution of Washington, on the temperature scale as defined by the nitrogen thermometer at high temperatures. Later (1928-1947) I had the opportunity of helping to apply this experience to the pyro-metric problems of the steel industry. Because of the range of its temperatures, the multiplicity of the methods used, and the variety of its purposes, pyrometry in the open-hearth process has always offered a fertile field for both research and development. I am therefore devoting an hour to the subject of temperatures in the basic open-hearth furnace, the furnace that makes most of our steel in the united States. I would direct your attention particularly to the choice of the first two words in the title of the Lecture. One sometimes hears or reads of the ((temperature of such-and-such a furnace," as if it were a single, measurable, characteristic quantity. I need hardly emphasize to any one who has ever operated a furnace or a kiln that " temperature of the furnace " is a meaningless phrase. Even if we confine our attention to the space enclosed by the roof, walls, and hearth of an open-hearth furnace, it is doubtful whether any such space has ever been so uniform in temperature that the phrase would have a meaning. In any furnace, there are many different temperatures, capable of being measured at many different places, and actually being measured for several different purposes. These pyrometric purposes, methods, and results, if given in detail, would expand this lecture into a book on the basic open-hearth process. I must therefore confine myself to a statement of the range of temperatures as they have been observed in various parts of the furnace, indicating in a general way why they are measured, and mentioning the methods that are available without attempting to describe these

Jan 1, 1949

By Robert B. Sosman

The chance that a Howe Memorial Lecturer will be able to refer back to a personal contact with the distinguished metallurgist for whom this lectureship is named grows steadily I I did not have the pleasure of his personal acquaintance, but I did receive from him in 1916, quite unexpectedly, a letter commenting On a paper that I had recently published27 On "Types of Prismatic Structure in Igneous Rocks." The paper was written for geologists and petrologists, but it had an application, naturally, to the crystallization of iron and steel in a mold. The letter impressed me at the time, and still does, with the breadth of of Howe's interests and his perseverance in keeping up with the progress of any branch of knowledge that had metallurgical connotations. Scope of the Lecture During several years preceding the date mentioned I had worked in collaboration with Arthur L. Day and E. T. Allen8 at the Geophysical Laboratory, Carnegie Institution of Washington, on the temperature scale as defined by the nitrogen thermometer at high temperatures. Later (1928-1947) I had the opportunity of helping to apply this experience to the pyro-metric problems of the steel industry. Because of the range of its temperatures, the multiplicity of the methods used, and the variety of its purposes, pyrometry in the open-hearth process has always offered a fertile field for both research and development. I am therefore devoting an hour to the subject of temperatures in the basic open-hearth furnace, the furnace that makes most of our steel in the united States. I would direct your attention particularly to the choice of the first two words in the title of the Lecture. One sometimes hears or reads of the ((temperature of such-and-such a furnace," as if it were a single, measurable, characteristic quantity. I need hardly emphasize to any one who has ever operated a furnace or a kiln that " temperature of the furnace " is a meaningless phrase. Even if we confine our attention to the space enclosed by the roof, walls, and hearth of an open-hearth furnace, it is doubtful whether any such space has ever been so uniform in temperature that the phrase would have a meaning. In any furnace, there are many different temperatures, capable of being measured at many different places, and actually being measured for several different purposes. These pyrometric purposes, methods, and results, if given in detail, would expand this lecture into a book on the basic open-hearth process. I must therefore confine myself to a statement of the range of temperatures as they have been observed in various parts of the furnace, indicating in a general way why they are measured, and mentioning the methods that are available without attempting to describe these

Jan 1, 1949

By J. G. Peacey, G. Csicsovszki

The target of this study was to clarify the role of lead on the dissolution of gold in the (NH4)2S2O3-Cu leaching system via chronopotentiometry, linear sweep voltammetry and chronoamperometry. It was found that the dissolution of gold was significantly increased with lead concentration up to 10 mg/1 Pb in the system of 0.1 M (NH4)2S2O3 and 50 mg/1 Cu. \/oltammograms suggested that the anodic dissolution of gold was virtually independent of lead concentration in the range of 1-10 mg/1 in 0.1 M (NH4)2S2O3 solution while in solutions containing copper as well, addition of lead increased the anodic dissolution of gold.

Jan 1, 2011

By G. M. Evans, S. Mitra, A. V. Nguyen

As an alternative to the conventional flotation method, there has been continual research in an effort to enhance base metal ores and combustibles recovery using ultrasonics. These studies however were largely limited to the pre-treatment of ores for the removal of surface contaminants while the effect of ultrasonics on the bubble and pulp-phase interactions remained somewhat unexplored. Noting this deficiency, this study aimed to investigate the mechanistic effect of an ultrasonic field in an impeller less flotation cell specifically focusing on the bubble-particle interaction dynamics. A lab-scale flotation cell (capacity 1 litre) was designed, involving a vertically oriented ultrasonic probe (20 kHz, rated at 1.2 kW) and operated in the output power range from 1 to 20% with continuous liquid recirculation. Particle suspension was achieved by the combined action of recirculation and ultrasonic pulses. Interactions of coarse size glass ballotini particles (D32 = 314 μm) with bubbles (< 1 mm diameter) in the presence of a surfactant were studied, using high-speed imaging. Application of an ultrasonic pulse in the aqueous medium resulted in the generation of numerous microbubbles which increased with increasing input power and duration of the ultrasonic pulse time. Such periodic pulses introduced at a high level of turbulence in the pulp phase facilitated adequate bubble-particle contacts. Microbubbles played a key role in forming particle clusters which were observed to be floatable even in the absence of any carrier bubbles. When carrier bubbles were introduced, some of these particle clusters attached to the bubble surface and conveniently floated. It was noted that a favourable state of bubble-particle interaction was achievable to produce stable bubble-particles aggregates by suitably controlling the input power and period of the applied ultrasonic pulse. Keywords: Flotation, bubble-particle interactions, collision, attachment, detachment, ultrasonic pulse

Jan 1, 2020

By M. Yavuz

Determining the most convenient plant location is one of the most commonly encountered problems in engineering applications. This paper presents a fuzzy multiple attribute decision making (FMADM) model which is developed for the selection of the optimum plant location for natural stone factories in the mining industry. The criteria affecting the decision making process in natural stone industry were determined to solve the plant location problem in the FMADM model. To determine the optimum plant location for a new natural stone factory, which is planned to be established by a mining firm located in the Eskisehir region of Turkey, an analysis was carried out by incorporating the method and the analytic hierarchy process (AHP) method. The analysis shows that the Yager?s method can easily be applied to the selection of plant location in the natural stone and mining industry when the difficulties encountered in the application process of the AHP method is taken into account. Keywords: Natural stone, plant location, decision making, Yager?s method, analytic hierarchy process (AHP).

Jan 1, 2008

By R. A. Metz, William H. Breeding

The remarks that follow are based substantially on experience covering 45 years, 80% of which has been in placer work, rather than on a review of available literature. Most commercial placers have been deposited by the action of water. The richer and more difficult-to-mine placers are those in the headwater areas where gradients are steepest. The most lucrative placers are generally in intermediate areas where volumes are greater, fewer boulders are present, and gradients are from 3% to 1-1/2%. The higher volume, lower grade placers are in the lower reaches of river systems where gradients are lower. Where gold-bearing rivers have discharged into the sea, wave action can concentrate values on beaches, past and present. Most of the rich, readily accessible placers were mined by our forefathers. Current opportunities exist: (1) in remote areas where infrastructure has been absent in the past, or development has been prohibited by adverse ownership - political or commercial; (2) in deposits that could not be mined by equipment available to our forefathers; (3) in deposits unidentified by our forefathers; (4) where the-price-of-product/cost ratio is substantially better than in earlier years; or (5) a combination of those factors. When I entered the placer business in the late 1930s, and subsequently, a prevailing opinion believed that glacial deposits should be avoided as irregular in mineral content and composition, and unrewarding to explore and develop; yet an operator has been mining a fluvio-glacial deposit profitably for the past 17 years. Rich buried placer channels, often called paleo-channels were worked in the last century, generally by hand methods, and under conditions that would be unacceptable today. Exploration and mining equipment now available make some of these channels attractive targets. Well-known examples are in California and Australia. The formation of a commercial placer requires a source of valuable minerals. Above primary deposits, there may be eluvial deposits formed by the erosion of gangue minerals and the concentration "in situ" of valuable minerals. Down slope from these deposits are the hillside or colluvial deposits, and below them are the alluvial deposits of redeposited material. Most of the great placer fields of the world are the result of several generations of erosion and deposition. Well-known examples are in California and Colombia. Gold is a very resistant and malleable material, and gold placers may extend for 64 or 80 km (40 or 50 miles) along a river system. Platinum is less malleable, but is very resistant to disintegration. Diamonds are extremely hard, and (especially gem diamonds) may be found over great lengths of a river system. Cassiterite is less resistant to disintegration, and tin placers seldom extend over two miles without resupply from an additional source or sources of mineralizaton. Tungsten minerals are generally more friable, and within a few hundred yards of the source disintegrate to the point that they are uneconomical to recover. Rutile, ilmenite and zircon placers generally result from the weathering of massive deposits, and may be encountered over extensive areas; most are fine grained and durable. What does a geologist or mining engineer look for in placer exploration? The old adage to look for a mine near an existing mine is still valid. You need a source of valuable mineral. Then you require conditions for concentration, which means a satisfactory gradient and/or other conditions that will permit heavy minerals to settle. Nicely riffled gravel, often called a shingling of the bars, is conducive to placer formation. Coarser gravel is logically associated with coarser gold. Excessive clay and/or high stream velocities in narrow channels can carry gold far downstream and distribute it uncommercially over a large area. When material is extremely fine, in situ weathering and concentration become more important. Placers frequently occur distant from lode mines, and one must remember that in a larger watershed the exceptional floods that occur once in a hundred or a thousand years can move great quantities of material long distances. The carrying power of water is said to vary with the fifth or sixth power of its velocity. I am not ready to disagree with Waldemar Lindgren and accept that many commercial placers are substantially enriched by the chemical deposition of gold from solutions; however, I have seen crystalline gold in clayey material quite distant from known sources of primary gold that is dif-

Jan 1, 1992

By D. A. Lindsey

Gravel lithology affects the quality of aggregate because different rock types in gravel have different physical and chemical properties. The lithologic composition of alluvial gravel reflects the composition of its source terrane and the variable effects of weathering and transport on each rock type. This report discusses lithologic controls on aggregate quality in the mountain-front environment of the Colorado Front Range. Lithologic controls on aggregate quality of gravels were evaluated using pebble count data. Gravel lithology along the Front Range shows both temporal and regional variation. The principal variable in gravel lithology is quartz plus quartzite, of which quartzite is commonly more abundant. Large quantities of metaquartzite derived from the mountain front southwest of Boulder, Colo., were dispersed northeastward during deposition of the oldest Front Range gravels. Average quartz plus quartzite is greatest in the oldest gravels. Aggregate quality is probably enhanced by large quantities of quartzite. Abundant volcanic rocks in gravel may enhance aggregate quantity, but such occurrences are local in extent. Abundant sedimentary rocks in gravel, mainly sandstone near the mountain front, may decrease aggregate quality.

Jan 1, 2002

By Henry Zhang

This paper presents two case studies of large diameter driven tubular steel piles for the ongoing Woolgoolga to Ballina Pacific Highway upgrade (W2B). This project forms part of Australia’s largest regional infrastructure project and will upgrade about 155 kilometers of highway to four-lane, divided road. There are more than 170 bridges on W2B, and driven tubular steel piles are adopted on 43 bridges between Glenugie and Ballina. Driven piles terminating in soil or basalt is a big challenge faced by both designers and piling contractors due to 1) the uncertainty of expected pile unit shaft and base resistance in different soils; 2) whether plugging is formed; and 3) highly variable basalt strength and thickness near top of the rock. If these risks are not adequately managed during design or construction stages, it could lead to unexpected project delay, extra time and cost or pile toe damage in basalt. This paper describes two case studies, one for piles designed to terminate in soils and the other for piles designed to terminate in basalt. How these risks were assessed and managed during detailed design, procurement, hammer selection, pile installation and verification will be discussed in details with lessons learnt summerised in the conclusion.

Nov 1, 2022

By E. C. Tarpley, H. M. Cooper, R. F. Abernethy

"INTRODUCTION The determination of moisture in coal is an empirical test, because the time, temperature, and equipment are specified. The essential features of the equipment, and details of the procedure are given in A.S.T.M. Designation: D271-44 5/. According to the specifications, the following features should be incorporated in the equipment used:1. Oven must have uniform temperature in all parts.2. Oven must be constructed with minimum of air space.3. Oven must have means of changing the air two to four times per minute.4. Air must be dried over sulfuric acid (sp. gr. 1.84).The analytical procedures governing most of the nation's coal purchases are those given in A.S.T.M. Standards referred to above. These standards are general and of such scope as to cover all ranks and types of coal. In cases where only the moisture is required, a faster method than the standard procedure is desired.The semi-automatic moisture tester manufactured by the Brabender Corp. has proved itself in many industrial processes where the rapid estimation of moisture is of vital importance. With the approval of A. C. Fieldner, chairman, A.S.T.M. Committee D-5, and through the courtesy of Lowell Malan, chief chemist, United Electric Coal Companies, who loaned the tester, tests were made to determine the feasibility of using this instrument to determine the moisture in coal."

Jun 1, 1948

By C. E. Henning

The total number of petroleum refineries in the United States on January 1, 1958, was 318 and their total crude-oil throughput capacity was 9,407,707 barrels per day, according to the Bureau of Mines annual survey. During 1957, 3 new refineries began operating while 4 refineries were retired. Although there was 1 less refinery, the total crude-oil throughput capacity at the beginning of 1958 was 284,033 barrels per day, or 3 percent, more than the January 1, 1957, level. During 1957 all refinery districts showed increases in capacity. The largest increase, 27 percent, occurred in the West Coast district followed by the Indiana-Illinois-Kentucky district with 14-percent increase and the Texas Gulf Coast district with 13-percent increase. The national increase in capacity had the effect of raising the capacity of the average refinery from 28,601 to 29,584 barrels per day. New crude-oil capacity under construction on January 1, 1958, totaled 185,265 barrels, and an additional 297,885 barrels capacity was reported building as replacement for existing facilities. Included in total new construction were 2 new refineries, 1 in Washington and another in Texas, with planned processing capacities of 45,000 barrels and 8,550 barrels per day, respectively.

Jan 1, 1958