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By AIME AIME

AT the end of September, ' the metal-producing industries were almost prostrate, the production of fuels was largely curtailed, there was a fair degree of activity in general manufacturing, while retail trade was moderately good. Looking at industry on the whole, there was a large percentage of unemployment, the degree of which has increased, progressively, month by month since the beginning of 1921. There is the prospect of much destitution and misery this winter; yet while' in some, quarters, idle workers are already being fed from, commissaries; in other quarters profligacy; in "spending continues, unabated. Amid this confusion in conditions there is;' much that appears paradoxical, but in fact it is not so and indeed everything is running pretty true to form: Such activity in production as there is to be seen is mainly in textiles; - leather goods, foodstuffs, etc., i.e., consumption goods for immediate use. Even in hard times 105,000,000 people must buy a good deal of clothing and food. Besides this there is indispensable repair work and- maintenances. Thus, the good business of the year in white lead for painting. The chief uses for the metals, however, are in the production of capital goods, and except for occasional and special reasons nobody in his senses is capitalizing anything at present prices for labor. Hence several millions of men are idle. The impoverishment of Europe and the exhaustion of her credits adds to this by curtailing our export trade.

Jan 1, 1921

Abbey, Robert Graham, District Mgr. The W W. Sly Mfg. Co,. 50 Church St, New York, N. Y. '21 Abbott, A. N., Mines Supt., Mazapil Copper Co., Ltd ..Concepcion del Oro, Zac., Mexico. '23 Abbott, Argyle Campbell, Dev. Dept, E I du Pont de Nemours & Co, Wilmington, Del. '29 Abbott, Clarence E., V.P, Charge of Raw Materials, Tenn. Coal, Iron & R. R. Co, 1242 Brown-Marx Bldg, Birmingham, Ala. '04 Abbott, Louis Benjamin, Chief Engr., Elkhorn Div., Consolidation Coal Co, Jenkins, Ky. '15 Abeel, George H., Jr., Cons. Min. Engr Box 427, Santa Monica, Cal. '18 Abel, Albert E., Asst. to Pres, Valley Mould & Iron Corp Hubbard, Ohio. '19 Abel, Raymond L., Asst. Prof., Dept. of Pet Refin., Univ. of Pittsburgh Pittsburgh, Pa. '28 Abell, Leo M., Research Engr, Sullivan Concentrator Chapman Camp, B. C., Canada. '31 Abernathy, George Elmer, Prof. of Geol. & Min . Kansas State Teachers College, Pittsburg, Kans. '20 Aborn, Robert H., Research Lab, U. S. Steel Corp. Lincoln Highway, Kearny, N. J. '19 Abozeid, Mahmood, Dept. of Mines & Quarries Cairo, Egypt. '26 Abraham, Arthur W. Box 1466, Bakersfield, Cal. '20

Jan 1, 1923

By Waldemar Lindgeen

PART I.—General Features. PAGE Purpose and Extent of Inquiry ; Definitions (Fissure-Veins, Metamorphism, Metasomatism, Impregnation, Cementation, Weathering); Metasomatism in Connection with Mineral Deposits, Especially Fissure-Veins; Calcu lation of Analyses ; Criteria of Metasomatism; Crystallization of Sec ondary Minerals in Other Bodies; Secondary Alteration of Veins; Structure and Composition of Metasomatic Vein-Rocks and Their Rela tion to General Metamorphism,.759 PART 11.—Minerals Developed by Metasomatic Processes in Fissure-Veins. Quartz, including Chalcedonite and Opal; Rutile and Anatase; Fluorite; Calcite ; Magnesite and Dolomite ; Siderite; Muscovite and Sericite ; Biotite; Chlorite; Pyroxene and A mphibole; Garnet; Epidote ; Ortho clase ; Albite ; Tourmaline ; Topaz ; Kaolinite ; Zeolites ; Pyrite ; Mar casite ; Chalcopyrite ; Arsenopyrite; Pyrrhotite ; Galena; Zinc-blende and Other Sulphides; Tellurides; Native Copper ; Gold and Silver,. 601 Resistant Minerals,........... 619 PART III.—The Fissure-Veins Classified According to Metasomatic Processes. 1. Topaz-Cassiterite Veins (Altenberg and Zinnwald, Saxony ; Mt. Bischoff, Tasmania),..........620 2. Scapolite-Apatite Veins,.........625 3. Tourmalinic Gold-Copper Veins,.. 626 4. Biotitic Gold-Copper Veins,........ 641 5. Propylitic Gold and Silver Veins (General Features; Comstock Lode; The Veins of Nagyág, Hungary; Pachuca, Mexico ; New Zealand; Alaska ; Silver Cliff, Colorado; Silver City, Idaho),. .. .645 6. Fluoritic Gold-Tellurium Veins (Cripple Creek ; Other Occurrences),. 654 7. Sericitic and Kaolinitic Gold- and Silver-Veins (General Remarks; The Freiberg Veins ; De Lamar, Idaho; Summit District, Colorado),. . 6.58 8. Sericitic and Calcitic Gold-Silver Veins (The Gold-Quartz Veins of Cali fornia ; Idaho Types ; San Juan, Colorado ; Treadwell Mine, Alaska ; Gold Veins of Ontario, Canada; Schwarzwald Fissure-Veins),. . 664

Jan 1, 1901

By R. E. Robinson

I shall present a concept for the development of the resources of this country and its neighbours that repre¬sents a fantastic challenge to our scientists and entre¬preneurs. This concept offers prospects of development that must make our previous achievements seem equivalent only to the first act in a drama enacted on the stage of Southern Africa. I hope to illustrate how, in Act Two, chemistry will play a dominant role, and chemists and chemical engineers will be among the principal actors.

Jan 1, 1980

By E. K. Stanek

This report contains the results of an investigation into the feasibility of periodically measuring parameters of the insulation for a mine electrical power system in order to detect incipient faults. The variety of insulation parameters evaluated included insulation resistance, dissipation factor, power factor (vs. applied voltage), current harmonics, leakage current, infrared radiation, as well as certain circuit breaker parameters and tests. In order to augment field tests a program of accelerated life testing was also carried out. Apparent inconsistencies in data were identified as the result of environmental effects, primarily temperature and relative humidity. A series of environmental tests were conducted to develop correction factors that allow one to refer measured parameters to standard conditions. A portable data collector was develop-ed to aid in the accurate collection and analysis of laboratory and field data. The primary conclusion is that insulation deterioration can be measured and failure predicted with reasonable confidence. The secondary conclusion is that most of the tests are impractical in the field although useful in the laboratory. Infrared sensing, insulation resistance and dissipation factor are the best insulation field tests when portability is taken into account.

Jan 1, 1979

By H. R. Wells

The Blackbird district, Lemhi County, Idaho, has long been recognized as a potential source of cobalt and copper. However, the comparatively low grade and small size of the known ore bodies, the small demand for cobalt, and. the lack of adequate roads throughout the region precluded extensive exploration of the early discoveries in the area. Recent advances in alloy metallurgy, accentuated by wartime activities, greatly increased the demand for sources of domestic cobalt. Beginning In 1941, engineers of the Bureau of Mines conducted an examination and exploration program in the Blackbird district. This work was supplemented by an exploration program by engineers of the Howe Sound Mining Co., 730 Fifth Ave., New York 19, N.Y.

Jan 1, 1948

By Kenneth L. Norris

Stonegate Agricom Ltd. is currently conducting exploration and development drilling of the Paris Hills Phosphate Project (Paris Hills Project) located in Bear Lake County, southeastern Idaho, 3.2 km west of the towns of Paris and Bloomington, Idaho. The project is located adjacent to a highway and 19 km by paved highway to Montpelier, Idaho where the Union Pacific Railroad system is located. Power and water are available locally. The nearest metropolitan centre is Salt Lake City, Utah approximately 225 km by road to the south-west of the property. The Paris Hills Project encompasses an area of approximately 856 hectares. Property holdings consist of three (3) patented lode mining claims and 16 contiguous fee parcels (some with federal phosphate leases). Active open pit phosphate mining operations are located in surrounding counties in south-east Idaho and are owned and operated by Agrium Inc., Monsanto Company and J.R. Simplot Company. The Paris Hills Project is located near the centre of the Western Phosphate Field which constitutes the most extensive phosphorite beds in the United States. Phosphate beds of the Western Phosphate Field occur within the Phosphoria Formation of Permian age and extend over an area of more than 350,000 km2 including extensive areas of Idaho, Utah, Wyoming and Montana. At Paris Hills the phosphate mineralized beds occur in the overturned limb and the horizontal limb of the Paris Syncline. Grades and thicknesses in both the western overturned limb and the eastern horizontal limb of the anticline are similar. The vast majority of potential mineralization occurs in the horizontal limb which underlies most of the property holdings. Mineralization in the overturned limb has a strike length of over three (3) kilometres and extends from the surface to a depth exceeding 300 m depending on location along the north-trending strike of outcrops. Depths of the horizontal limb range from surface along the north side of Bloomington Canyon to estimated depths of 915 to 1,035 m at Paris Canyon. The property contains an Inferred resource of 109.6 million tonnes at 23.6% P2O5 over two mineralized horizons. The phosphate zones have a strike length of over 3 km and extend from surface to a depth of at least 900 m. Drilling commenced late in the 3rd quarter of 2010 and is planned to continue through 2011. The drilling was planned to target an area of potentially higher grade phosphate mineralization and better define and upgrade the current resources.

May 1, 2011

By H. L. Paterson, R. R. Keays, M. J. Donaldson, D. J. Boyack, M. F. Smith, J. J. Gresham

"Albite-rich sedimentary rocks that contain abundant Fe sulphides occur in the lower portion of the ultramafic sequence at Kambalda and their broadly antipathetic relationship to most of the nickel orebodies is well documented. These sediments generally contain less than 0.1% Ni, but nickeliferous equivalents with 0.3 to >6% Ni occur locally in close spatial association with more typical volcanic peridotite-associated massive, matrix and disseminated ores. Nickeliferous sediments have been mined at several locations at Kambalda but, collectively, they constitute less than 2% of the total Kambalda nickel reserve. The nickeliferous sediments occur both on the ultramafic-footwall basalt contact and within the lower part of the ultramafic sequence, and are usually less than 5 m thick. They are commonly finely laminated rocks with a cherty appearance, composed essentially of layers of albite+quartz±amphibole, alternating with pyrrhotite+pentlandite±pyrite layers. Some contain a minor amount of carbon. The sediments are only of ore grade (> 1% Ni) immediately adjacent to massive Fe-Ni-Cu sulphides, which are interpreted as normal magmatic ores on the basis of geochemistry and the presence of distinctive ferrochromites. The nickel content of the sediments decreases to background levels (<0.1%) within about 20 m of the massive sulphides. In most locations the massive sulphides clearly have been emplaced tectonically within or adjacent to the sediments, which are commonly highly deformed. Typical nickeliferous sediments contain about 1% Ni, 0.1% Cu, 0.1% Zn, 400 ppb Pd, <0.2 ppb Ir and 10-200 ppb Au. They have lower Ni/Cu (average 10), higher S/Ni (average 6) and higher S/Se (average 11 200) than associated massive sulphides (average 40, 4.8 and 7400, respectively). The Pd/Ir ratio of the nickeliferous sediments (typically > 1000) contrasts markedly with that of associated massive sulphides (average ca 16).The high Pd/Ir values are similar to those which have been reported for hydrothermal Fe-Ni sulphides and barren sulphidic sediments of probable volcanic exhalative origin. They preclude a direct magmatic origin for the sulphides in the nickeliferous sediments, though S/Se and S isotope data indicate a magmatic source for the sulphur. The restriction of nickeliferous sediments to within about 20 m of normal magmatic sulphides and the lack of a widespread Ni dispersion halo suggest local redistribution of originally magmatic Ni. This probably occurred by diffusion and hydrothermal mobilization during deformation and amphibolite-facies metamorphism. Although not totally ruled out, a volcanic exhalative origin for the Ni seems unlikely."

Jan 1, 1984

By Ayman Tawadrous

Cave mining offers a flexible technique to exploit large, low grade, deep ore bodies with low operating costs. It is typically done in either a top down approach; i.e. sublevel caving, or in a bottom up approach; i.e. block or panel caving, to extract ore bodies that may have been previously considered unfeasible to mine. Sublevel Cave (SLC) mining, in particular, is a cave mining method based upon the utilization of gravity of blasted ore while the overlying host rock fractures and caves under induced stresses and gravity. Thereby the caved waste originating from the overlying rock mass fills the temporary void created by ore extraction to achieve a controlled collapse of the roof.

Jan 1, 2015

By R. August Heindl

A process for recovering manganese from open-hearth steel-plant slags was investigated. The proposed method of accomplishing this is indicated by the flow diagram in figure 1. Mixtures of open-hearth, steel-plant flush slags and limestone, so proportioned as to have molar [CaO -3P205] ratios of approximately 2, were fired at approximately 2,400° F. in an oxidizing atmosphere and then cooled slowly. This treatment produced a clinker consisting principally of two solid phases comprised of (1) various combinations of the oxides of manganese, iron, aluminum, and magnesium, probably in spinel complexes, and (2) a dicalcium silicate phase, which contains the phosphorus. Reduction of these clinkers with hydrogen or with gaseous mixtures containing CO, CH4, and other hydrocarbons at about 1,300° F. formed manganous oxide as well as varying amounts of ferrous oxide and iron. Carbon monoxide and mixtures of hydrogen and carbon monoxide effectively reduced the clinkers but also gave higher proportions of soluble iron when the manganese was extracted from the reduced clinkers by leaching at about 80° F. with ammonium carbonate solutions containing 26 to 28 percent ammonia and 15 to 26 percent carbon dioxide. It is believed that the manganese is in solution as an ammonia-manganese complex. Concentrations of about 90 grams of manganese per liter were obtained by batch countercurrent procedures. By distilling 50 percent of the ammonia, the ammonia-manganese complex was decomposed, and approximately 90 percent of the manganese was precipitated as the carbonate with the simultaneous precipitation of 15 to 30 percent of the iron, the larger amounts of iron precipitating in the continuous tests. The manganese-iron ratio in the product could be increased either by recycling more manganese from the distillation to the extraction or by aerating the liquor to purge it of iron before, rather than after, the distillation step. Calcination of the pelletized manganese carbonate in an oxidizing stmosphere at 2,000° F. or above gave a final product, Mn304, resistant to crushing and apparently possessing the other physical properties essential in a ferromanganese blast-furnace feed.

Jan 1, 1955

By Frank B. Fulkerson

Mining began in Pend Oreille and Stevens Counties about 1885, Lead and zinc have been the principal products, and the area has supplied nearly all the output of these metals in the State. Fend Oreille County&apos;s output of lead and zinc from 1902 to 1956 was 110,700 and 229,600 tons, respectively. The Stevens County total was 54,100 tons of lead and 87,600 tons of zinc. Copper ore was produced mainly from the United Copper mine, Chewelah district, from 1912 to 1920; the principal gold mine was the First Thought, Orient district, which was active from 1904 to 1942. Approximately 225 mines and prospects produced; most of the ventures were on a small scale. The total value of gold, silver, copper, lead, and zinc produced from 1902 to 1956 was $75.2 million in Pend Oreille County and $39.4 million in Stevens County. INTRODUCTION In compiling the figures for this report, use was made of Bureau of Mines permanent records of nine production, the annual tabulations of producing mines, and the Minerals Yearbook. Requests to publish individual data, obtained from the annual production canvass, were made to the latest recorded operators of all mines in the area. Response to this request was good; therefore, it was possible to make the tables nearly complete. In a few instances the producer requested that the production data remain confidential, and in others it was not possible to reach the mine operator at his last known address. The district and county tables combine statistics for all mines, including those mines whose output could not be published separately.

Jan 1, 1958

By J. Gao, H. O. Gekonde, S. V. Subramanian

"The functional role of inclusions at low cutting speeds is to promote ductile fracture in chip formation process, whereas the role of inclusions at high cutting speeds is to prevent tool crater wear by suppressing the tribological phenomenon of seizure at the tool-chip interface. Glassy oxide inclusions are engineered into the workpiece to form a viscous layer in-situ at the tool-chip interface at high cutting speeds. The viscous layer lubricates the tool-chip interface to prevent the seizure. In comparison with the large volume fraction of inclusions needed for promoting ductile fracture at low cutting speeds, the amount of inclusions required for lubricating the toolchip interface at high cutting speeds is very small and is in the range that is typical of clean steels. The chip fracture process at high cutting speeds is aided by strain rate hardening of the matrix, which facilitates chip disposal of relatively clean steel.Inclusion engineering for high speed machining involves the control of the rheology and composition of inclusions to meet target viscosity at the tool-chip interface. The application of thermodynamic models in controlled production of inclusions in steels designed for high speed machining is discussed."

Jan 1, 1998

By John Convey

"IRON ORE was first smelted in Canada about the year 1736 at Les Forges, Quebec -a most appropriate name for such a historic locale. During these early years of the 18th, 19th, and first quarter of this century, about six million tons of ore were mined and employed in the manufacture of items ranging all the way from kettles, stoves, and cannon for the early settlers to weapons of war for the allied armies of World War I.But this symposium on iron ore is not concerned with this early period. Instead, it is concerned with the iron ore industry of today -an industry which will soon be-come one of the two most valuable mineral industries in Canada.The subject in its broad geographic and economic aspects will be introduced by Mr. Buck; Dr. Harrison will describe the geology and origin of the principal iron ore deposits; Dr. Downes will go into beneficiation as it applies to iron ores; and Mr. Gertsman will discuss primary processing. The symposium will not deal with the steel end of the industry, because that phase itself could well form the subject of a symposium."

Jan 1, 1955

Mine pit slopes in the Pacific Rim are a geotechnical challenge because of the complex geology in which they are developed. Mines are currently being fast-tracked to meet the increase in commodity prices, often resulting in some reduction in ground studies and short-cutting of design procedures. In addition, the resources boom means that skilled personnel are in relatively short supply. At a time when mine pits are getting bigger and deeper, and the engineering is getting more demanding, there is an increased demand on managers to effectively implement the work. &nbsp; Experience both in New Zealand and the Philippines, display the complex range of geological environments in which pits are being excavated. Working in these conditions has shown that successful geotechnical design requires a strong geotechnical model based on sound geology. An appropriate level of investigation and analyses results in a certain level of understanding for the mine design. There is a point where additional expenditure (on investigation and analyses) is not warranted based on the expected minimal impact on decreasing the level of perceived risk on the project. For most projects in our experience the analytical methods and complexity of geotechnical assessment changes increases as the level of knowledge grows.

Jan 1, 2006

By Deno M. Pappas

This report presents results of a U.S. Bureau of Mines study of longwall gob material. The objective of this work was to determine material stiffness properties of the gob for use in numerical models of rock mass response to longwall mining, Photographs of actual mine gob were digitized to obtain approximate particle size gradations of gob material. The gradation curve was shifted down to a laboratory scale, and 20 uniaxial compression tests were conducted. Varying the maximum particle size was not found to affect the stress-strain behavior, but changing the gradation appeared to influence the stress-strain behavior. The stress-strain relationship of the simulated gob material was nonlinear, the stress-secant-modulus relationship was approximately linear, and the stress-tangent-modulus relationship was approximately a second-order polynomial function. Equations were generated from these curves, providing numerical modelers with a means to estimate gob moduli based on the stress level. In addition, the experimental data were statistically evaluated using multiple regression analyses, producing a series of equations to predict the secant and tangent moduli from the given stress level, bulking factor, rock strength, and thickness-to-width shape ratio of the particles.

Jan 1, 2010

By Terrence M. Carroll, Chu E. Ho, Dimitrios Niarchos

"Construction of the new extension to Terminal 4 at John F Kennedy International Airport in Queens, New York involved the application of tapered piles for foundation support. Initial design based on past load testing experience had indicated that a pile depth of 65 feet was necessary to achieve a capacity of 394 tons. However, piles with a single length of 62 feet were ordered and installed, which led to marginal performance of the piles. This paper presents the technical considerations for mitigating the situation based on a systematic review of three preliminary pile load tests and dynamic capacity measurements on the shorter piles. Consideration was given to the long term gain in capacity of tapered piles due to set up in the Glacial Sand. The observational approach to the evaluation of piling performance adopted on this project resulted in salvaging many piles which failed to comply with the specified driving criteria. It was acknowledged that a more prudent course of action was for the Contractor to have ordered more appropriate pile lengths that allowed for potential variation in soil conditions across the site. The 4.6% saving in pile material did not warrant the effort that was required to mitigate the 39% of installed piles that did not meet the specified driving criterion.INTRODUCTIONAn expansion project at John F. Kennedy International Airport in Queens, New York involved the Phase 2 extension of Concourse B at Terminal 4. The site consists of 4 to 5 feet of pavement over about 10 feet of hydraulically placed sandy fill. Below this is a layer of marsh deposit, comprising of soft organic clay and peat, up to about 11 feet thick. Beneath the marsh deposits is a deep layer of glacial sand which extends to well over 100 feet below ground. Figure 1 shows the typical subsurface profile at the site. The new structures were supported on 223 steel tapered piles. The piles consisted of a straight steel pipe 18 inches in diameter and 0.375 inches thick, with a 25 feet long tapered bottom section (diameter varying from 18 inches down to 8 inches at the pile toe). The piles were first driven to the founding depth and subsequently in-filled with concrete. The concrete strength (fc) specified was 4,500 psi and the yield strength of the steel piles (fy) was 50 ksi. Initial pile design, based on earlier experience with static pile load testing for Phase 1 development at the same terminal, indicated that a pile length of 65 feet was necessary. However, piles with a single length of 62 feet were ordered and installed by the Contractor, leading to marginal performance of the piles. This paper presents the technical considerations for the adoption of alternative pile driving criteria, based on a systematic review of the preliminary static load test results for the present site and PDA measurements obtained during pile installation, in order to accommodate the capacity of the shorter piles."

Jan 1, 2017

By R. W. Geehan

The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. Bureau engineers made a preliminary examination of the Morefield mine early in 1943 and recommended investigation by trenching and diamond drilling, The Bureau of Mines conducted work from August to December of 1943, which indicated that the Morefield mine was a favorable location for an experimental mining program. The Bureau of Mines carried on such a program from September 1947 to March 1949. The property investigated is 30 miles southwest of Richmond in Amelia County, Va. (fig. 1). During World War II mica and beryl were shipped from the Morefield mine, but after the high prices and premiums paid during the war years were not available the mine was closed.

Jan 1, 1953

By Joël P. T. Kapusta

Back in 1995, Air Liquide and Union Minière presented a joint paper at the Copper 95 – Cobre 95 Conference in Santiago, Chile, describing the first full scale plant trials of shrouded sonic injection in a Hoboken converter at the Hoboken smelter in Belgium. Almost a quarter of a century later, the technology known as ALSI, or Air Liquide Shrouded Injection, has been tested or commercially implemented in several copper and nickel smelters. Despite these successes, the copper industry did not adopt it widely in the same manner the steel industry adopted the Savard-Lee tuyere in the 1970s and beyond, not even in the way the lead industry adopted it with the Queneau-Schuhmann-Lurgi, or QSL, process. The development and implementation of bottom-blowing smelting and converting technologies in China in the last ten years, however, changed the industry’s perception that high- and ultra-high oxygen injection in copper smelting and converting was indeed possible under specific process conditions. In this paper, I retrace the key learnings of my journey with sonic injection over the twenty five years from my humble beginnings in my early years with Air Liquide, through plant trials and technology implementation in the late 1990s and into the first decade of the new millennium, and ultimately, to the most conclusive proof that the sonic injection design methodology I established is valid, and the calculation tools I developed are accurate. I conclude by sharing my thoughts about whether the deployment of the Savard and Lee legacy within the nonferrous industry was just a pipe dream or whether it will become a reality. INTRODUCTION In the context of lower quality ores and changing economic markets, copper smelters need to continuously innovate and improve to remain competitive and respect their corporate social responsibility engagements. One avenue towards this business, social, and environmental goal is to increase process intensity while lowering fossil fuel consumption to lower greenhouse gas emissions and reducing process off-gas volumes to better capture As and SO2–laden emissions. I believe high oxygen sonic injection for submerged tuyere copper bath smelting and converting is one technology that can help smelters achieve that goal of higher business, social, and environmental performance. Twenty five years ago, when I discovered that the Savard-Lee tuyere had revolutionized the steel industry (Savard & Lee, 1966; Knuppel, Brotzmann, Fassbieder, Savard, & Lee, 1972), I had a dream — or was it a vision? — that within the first decade of the new millennium, modern copper smelters operating submerged tuyere bath smelting and converting vessels will have implemented high oxygen sonic injection and will be reaping the financial and environmental benefits that the steel industry enjoyed in the 1970s. As we approach the end of the second decade of the new millennium, I have to admit that my dream has been all but shattered as the majority of copper bath smelting and converting vessels today continue to operate under bubbling regime conditions. This mode of operation is archaic, still requires tuyere punching and blows at inherently low enrichment levels, particularly in converting, producing large volumes of process off-gases. Under such operating conditions, regulations and emission quotas for As, SO2, and particulate matter oblige smelters to use not just primary or secondary hoods, but sometimes even tertiary hoods. I vividly recall being told, fifteen or twenty years ago when visiting smelters to promote the application of the Savard-Lee tuyere in nonferrous processes, that implementing sonic injection was not economically viable due to the high cost of compressing air and oxygen. Some of the smelters I visited back then have since mandated their engineering partners to design and build secondary or even tertiary hoods. I cannot fathom how secondary and particularly tertiary hoods, with all of their auxiliary equipment and added ducting, could be more economically viable than purchasing and installing a few compressors, expanding the pipeline network for compressed air and oxygen, and installing a new control valve train to feed sonic tuyeres. Besides, adding hoods does not address the problem of As and SO2-laden fugitive emissions at its source but merely provides a costly mitigation for it by capturing larger volumes of process off-gases rather than reducing these large volumes in the first place. Moreover, hooding does not reduce energy consumption nor does it increase process intensity, two aspects that I believe are critical for smelters to remain competitive and sustainable in a deeply changing market environment.

Jan 1, 2019

By Charbel Khoury, Kwabena Ofori-Awuah, Kofi B. Acheampong

"Following heavy rains in spring of 2014, Prince George’s County officials issued a mandatory evacuation for homes in the Piscataway Hills subdivision of Fort Washington, Maryland where a landslide along a 1700-foot hillside destabilized homes, collapsed the single access road, and resulted in water and sewer mains break. Forensic investigations, including geologic assessments, test borings and in-situ Cone Penetrometer and Dilatometer soundings, were performed to evaluate subsurface conditions and provide stabilization options for the roadway and slopes. Post-failure ground movements were monitored using inclinometers. Critical failure planes were identified within the underlying 30-foot thick Marlboro Clay formation, a known geologic hazard with historic occurrences of landslides and slope failures.This paper discusses the remedial design for stabilizing the landslide and 60-foot hillside slope failure, and protecting the roadway. Amongst several feasible options, driven piles were selected in consultation with the County and retained contractor based on cost, environmental impacts and site constraints. Constraints included private ownership of hillside slope, upslope buildings safety; deep-seated failure, relocation of underground water and sewer mains, and accelerated construction schedule.Pile design included global slope stability analyses and lateral pile analyses using several loading configurations to optimize pile geometry and spacing, and determine a value-engineered design satisfying both serviceability and strength limit states to achieve long-term stability with factor of safety of 1.3. Soils within the active landslide plane were assumed to provide no resistance, while soils below the failure plane provided lateral resistance. This stabilization scheme, which extended along the 1700-foot roadway section and toe of hillside slope area, consisted of 410 steel HP16x141 piles in two to three rows driven to depths between 60 and 70 feet below the Marlboro Clay stratum at 5 to 7-foot spacing."

Jan 1, 2017

By Renfeng Song, Shaoyan Wang, Zhiqiang Zhang, Ke Guo

Leaching titaniferous magnetite concentrate with alkali solution of high concentration under high temperature and high pressure was utilized to improve the grade of iron in iron concentrate and the grade of TiO2 in titanium tailings. The titaniferous magnetite concentrate in use contained 12.67% TiO2 and 54.01% Fe. The thermodynamics of the possible reactions and the kinetics of leaching process were analyzed. It was found that decomposing FeTiO3 with NaOH aqueous solution could be carried out spontaneously and the reaction rate was mainly controlled by internal diffusion. The effects of water usage, alkali concentration, reaction time, and temperature on the leaching procedure were inspected, and the products were characterized by X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy, respectively. After NaOH leaching and magnetic separation, the concentrate, with Fe purity of 65.98% and Fe recovery of 82.46%, and the tailings, with TiO2 purity of 32.09% and TiO2 recovery of 80.79%, were obtained, respectively.

Jun 16, 2021