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By L. C. Raymond

Valuations in the mineral industry differ from those of other enterprises because mines and oil wells have a definite life so cannot be considered a perpetuity. This requires that in any mineral-property evaluation the recovery of invested capital is necessary during the life of the property. Capital write-offs for nonextractive industries are assumed to be continuously plowed back to sustain the operation and produce yields on the capital invested. The extractive or mineral industry, however, generally attempts to return to the investor both interest and principal during the life of a property. Normally this is done currently and the dividend includes both items. Where the mineral property possesses large reserves and the life factor approximates a perpetuity, the return on investment is generally comparable to that of industrial stocks. The valuation of a mineral property, at best, is based on educated estimates and judgment factors. This is particularly true as it relates to estimating selling prices over a long term or assessing the quality of management. Also, it is possible to make various assumptions as to rapidity of working out the deposit, varying time for start-up of operations, varying earning rates, so as to obtain different results with the same basic facts. Thus it is not surprising that two engineers, irrespective of their abilities, may not agree exactly even when given the same facts, but their results should be close enough to be used in establishing a fair value for trading purposes. The valuation is no better than the source of basic data and the soundness of judgment factors. Fundamentally the basic principles of mineral valuation are similar for base metals, sulfur, oil, or any other mineral. Each mineral, however, requires an engineer to have a knowledge of such factors as its occurrence, distribution, mining and processing methods, and marketing problems in order to gather and analyze all the facts and data that have a bearing on the earning potential of the property. Present Value of a Mineral Property In essence the present value of a mineral property is a sum of money in today's dollars that future income from the property are worth. It differs from the total anticipated earnings by the amount of the interest that the unrecouped investment could be expected to earn during the period of recoupment. Thus, if one could accurately estimate what a mineral property will earn during its life, after deducting all operating, administrative, capital, interest, and tax charges, the determination of present value would be a relatively simple mathematical calculation. Normally, where the expected life of the mineral property extends beyond 20 or 25 years, the discounted value of earnings beyond this period is relatively small. The petroleum industry generally discounts the annual cash flow of an operation rather than earnings since, for tax-saving purposes, earnings are kept

Jan 1, 1976

By O. C. Baptist

This report presents results of an investigation undertaken by the Bureau of Mines to determine the clay content of typical petroleum reservoir sands in Wyoming and the effect of clay content on the permeability behavior of the sands. These results should have significance in determining the feasibility of injecting water into the sands for secondary recovery and in estimating the probable damage incurred by these sands if invaded with filtrates from water-base drilling muds. The results of air-, brine-, and water-permeability determinations are given for reservoir sands in three Wyoming fields. The amounts of materials of "fine silt and clay size" (Wentworth scale) in the sands and the types of clay minerals present, as identified by X-ray diffraction methods, are also presented and discussed.

Jan 1, 1955

By Kenneth R. Hancock

Iron oxides are unique in that they are the only significant colored mineral found in a natural state suitable for use as a pigment after being pulverized to pigmentary size. The current world production of iron oxide pigments is estimated by the author to be between 499 and 590 kt (550,000 and 650,000 st) based on 1979 data. The fact that highly colored natural deposits of iron ore are found throughout the world accounts for its use in prehistoric man's artistic cave paintings. These early artists did not realize that they had established man's first paint test fence which now has some 20,000 years of exposure. In addition to abundance, constituting about 7 % of the earth's crust, iron oxides have the advantages of low cost, permanency, and are not toxic. Through the centuries, succeeding civilizations have utilized iron oxides as a major source for decoration and protection when coloring was desired. In the last century the chemical industry has improved on nature by developing a complete range of synthetic iron oxide pigments which surpass the pigments produced from natural iron ores in uniformity, color quality, and chemical purity. In the United States alone, the combined production of natural and synthetic iron oxides produced sales of over $28,000,000 in 1970 (Stipp, 1970) and increasing to $97 million by 1980 (Spinrad, 1980). Nomenclature With the increasing importance of the synthetic iron oxides it is necessary to make a distinction between the natural or mineral pigments and the synthetic pigments. Natural pigments are those products which are derived from selected ores and should not be confused with iron ores mined for steel production. Iron ores that are mined for steel must be capable of being mined and reduced to iron on a commercial basis. These ores are selected on the basis of iron content and processing economics. It is therefore unusual when iron ores for steel production are suitable for use as mineral pigments. Natural pigment ore sources are selected for their special physical-chemical properties and can command a premium price. Synthetic pigments, and in this instance iron oxides, are those pigments produced from basic chemicals. Through chemical synthesis pigmentary sized particles are produced as opposed to comminution, the major procedure common to all natural iron oxide pigments. Classification An important characteristic of a pigment is its color and, therefore, a logical separation can be made on this basis. A. Yellow Iron Oxide Pigments 1. Natural mineral origin a) Goethite b) Lepidocrocite c) Ochres d) Siennas e) Limonite 2. Synthetic pigments a) Goethite B. Red Iron Oxide Pigments 1. Natural mineral origin a) Hematite b) Siderite (calcined) c) Pyrites (calcined) 2. Synthetic pigments a) Hematite C. Brown Iron Oxide Pigments 1. Natural mineral origin a) Umbers b) Limonite (calcined) c) Siderite (calcined) d) Goethite (bog ore or sulfur mud) 2. Synthetic pigments a) Blends of hematite, goethite, and magnetite

Jan 1, 1983

"The Cordillera contains numerous porphyry deposits and prospects, many containing economic quantities of copper, molybdenum, gold and tungsten. Over the lost twenty years, different phases of exploration have been driven by individual commodity prices and new discoveries. Exploration methods have remained largely unchanged since the 1960s and 1970s with the range of techniques chosen for each situation depending on the stage of the program, the type of porphyry target and the local environment. Improvements or changes to techniques have resulted from awareness of specific features in new deposits or regional problems. During the last ten years much of the emphasis has been on the re-evaluation of known porphyry deposits with more exploration in areas previously recognized as prospective. Re-evaluation of known deposits has resulted in increased reserves, often with improved gold grade, and the discovery of new zones. Several new deposits have been discovered including gold-only deposits of probable porphyry affinity.Research related to porphyry deposits has followed trends in exploration and has been directed toward the type of deposits that have been of current interest. In addition to research on specific deposits and areas, general research related to porphyry deposits has addressed three broad themes. The first theme involves the role of tectonic processes and the nature of source regions. Although different in detail, recent tectonic models suggest that a tectonic change or hiatus may be important for the generation of metal-rich magmas from various source regions and subsequent fractionation that permits volatile saturation. The second theme is based on magmatic processes, particularly the generation of a volatile phase enriched in metals. This research supports the general orthomagmatic model for porphyry deposits and has helped to define the influence of specific variables in the generation of different types of porphyry deposits. Finally, research on alteration and mineralization has provided evidence for different types of fluids and fluid processes involved in the formation of porphyry deposits. These data also support the orthomagmatic model but indicate additional complexity in magmatic-hydrothermal systems including the role of external fluids. Although important advances have been made, research has had a limited impact on exploration.Exploration and research on deposits that occur in the peripheral and upper parts of porphyry systems have been important over the last ten years. Although considerable advances have been made, the relationship of different styles of peripheral mineralization to magmatic processes in the core of the system remains ambiguous. An improved understanding of the processes that generate zoning, peripheral mineralization, and the surrounding alteration envelopes would be beneficial to exploration."

Jan 1, 1995

By E. B. Kester

A study of the composition of the corresponding fractions of a primary and a high- temperature tar was undertaken to throw light on the net results of the pyrolysis of the primary products of coal decomposition in high-temperature coking practice, with reference both to total quantities of the chemically similar constituents and to their distribution throughout the boiling range. No exactly parallel investigations are on record. The distribution of substances in high-temperature tars, however, is fairly well understood. Such tars are more or less similar, for they consist of the more stable phenols, aromatic and olefinic compounds resulting from the pyrolytic decomposition of a wide variety of primary tar constituents. For example, from a typical distillation curve for high-temperature tar phenols4 it may be seen that the greatest portion of the phenols distills between 180° and 220° C., a fairly narrow range.

Jan 1, 1932

By Dendyuk TV

The possible use of combined (flotation/magnetic separation and magnetic separation/flotation) technologies involving the new flotation reagent systems for upgrading the iron ore concentrates, low grade manganese products and beneficiation of graphite-bearing dusts from integrated iron-and-steel works has been shown. It has been found that the absence of magnetic flocculation phenomenon worsens the reverse cationic flotation of oxidised iron ore concentrates and direct flotation of low-grade manganese products which require the use of modifiers possessing the flocculating properties. The synergetic mixtures of polymers have been proposed to be used as modifiers, ie polyacrylamide (PAA) with carboxymethyl cellulose (CMC) and polyacrylamide with industrial lignosulphonates (LST)

Jan 1, 1993

By Brain W. Lawrence

Sublevel stoping generally is a large-scale open stoping method. It sometimes is referred to as long-hole or blasthole stoping. This method usually is applied to strong ore bodies that require minimal support and are surrounded by strong country rock. The ore body should be fairly regular in shape and well-defined. The dip of the footwall normally should be sufficient to allow broken ore to gravitate freely, although the method has been adapted successfully to mine some of the flatter ore bodies. Sublevel stoping is not dependent on the width of the ore body. Widths of less than 6 m (20 ft), however, make the utilization of long-hole drilling techniques more difficult. The main criteria for sublevel open stoping are competent ore and stable host rock, regular ore boundaries, and a footwall dip that exceeds the angle of repose of broken ore. Basically, the method entails providing access to the ore body at various subintervals between the main haul- age levels in order to drill and blast the intervening ore. Stope drilling is carried out from drilling drifts on the sublevels, and the ore is blasted in slices towards an open face, which generally is vertical on the downholes and may be inclined towards the open face for the up holes. The blasted ore gravitates to the bottom of the stope and is collqcted through drawpoints. Fig. 1 illustrates a typical sublevel stoping mine. The method requires extensive ore body development with relatively high capital expenditures. How- ever, much of the development is in ore, and production costs are comparatively low. Productivity rates are in the 13.6 to 27.2 t (15 to 30 st)/manshift range. The drilling, blasting, and loading operations are performed independently, and equipment utilization is high. Large outputs can be obtained with few units and limited personnel. Dilution with waste rock may occur if ore boundaries are irregular or if caving occurs, but 100% of the ore within the stope usually is recovered. Pillar recovery sometimes is a problem. It is at this point that most of the waste dilution occurs. At the time data was gathered for this report (1973), the sublevel open stoping method was used by more than 21% of the metallic ore mines in the US (9 out of 42 mines producing 1088 + t/day (1200 + stpd) and provided more than 12% of the total metallic ore production from these mines. DEVELOPMENT Access to a sublevel open stope mine is gained by a slope or shaft that is normally sunk in the footwall of the ore zone, away from any possible effects from blasting or other production operations in the stoping process. Main level interval is selected and usually varies from 45.7 to 121.9 m (150 to 400 ft), depending on the vertical extent of the ore body, the number of drawpoints required to maintain output, and the eventual stope height. The main haulage drifts are located at the bottom of the stope horizon, either directly in ore or in the footwall, with access crosscuts at intervals. Raises are driven up through the ore to connect to the level above and provide access and ventilation to the sublevel drilling drifts, which are driven horizontally in the ore for the length of the stope. Depending on the drawpoint system to be used, the stope is either undercut by a raise-and-cone system, from a scram or slusher drift, or simply provided with a drilling drift from which access is made at intervals to the main haulage level. A raise driven either at the end or in the middle of the stope (if stope access is from both ends) provides a start for opening up a vertical slot across the stope to establish a free or open face for long-hole drilling and blasting. Sublevel stoping has proved to be a relatively safe and economical system.

Jan 1, 1982

By Hugo Leandro Rosa

A CBMM aplicou aços micro ligados ao nióbio em dois tipos de caçambas de carregadeiras de rodas que operam na usina de Araxá, Brasil. O objetivo foi avaliar os benefícios destes aços relacionados com redução dos custos, aumento da produtividade e vida útil dos componentes. Uma das máquinas analisadas coleta peças quentes de ferro nióbio para carregamento dos silos do britador. O uso de um aço ferramenta de alta resistência e resistente ao desgaste solucionou os problemas de deformação, desgaste e rachaduras durante o serviço, aumentando a vida útil da caçamba em cerca de 190%. A outra máquina avaliada foi uma carregadeira de rodas que opera na mina de minério de nióbio. O novo desenho com aços de alta resistência mecânica e resistente ao desgaste reduziu o peso em 14%, correspondendo ao incremento na capacidade de carga. A carga extra possibilitou um aumento na produtividade dos caminhões de 42 toneladas. Com os novos materiais, as trincas anteriormente encontradas na caçamba da pá carregadeira foram eliminadas, enquanto foi mantida a resistência ao desgaste antes oferecida pelo aço revestido com carbeto de cromo reduzindo também os custos de investimento em 7%.

Aug 17, 2017

By J. L. Tokich, A. R. Troiano

Since 1921, when Hull1 discovered that cobalt can exist in the face-centered cubic and hexagonal close-packed modifications, the transitions that occur in cobalt have been extensively studied. It is generally agreed that on heating the hexagonal lattice changes to the cubic structure at ternperatures ranging from 400° to 500°C although considerable doubt exists as to the exact temperature. Data concerning the temperature of the transformation on cooling are much less concordant and their interpretation has not been satisfactory. The study is further complicated by the fact that many investigators have reported the existence of a high temperature allo-tropic change in the range 850 to 1020°C, at which the cubic lattice reverts to the hexagonal modification. The transition on cooling, which has been reported as Occurring at various temperatures from approximately 400 to 100°C, is of particular interest. Troiano and Greninger2 have recently suggested and considered the possibility Of allotropic transformations occurring in pure metals by a shear-type, diffusionless (martensite) transformation. The case of cobalt was specifically discussed and certain observations of previous investigators evaluated in terms Of this type of Of Table 1 briefly outlines the methods and results Of previous investigators Of the transformation temperatures of cobalt. Materials and Methods The major portion of this investigatioll was performed with cobalt sheet containing a total of 0.2 pet impurities with carbon present to the extent of o,I pct. After melting in an induction furnace under an atmosphere of hydrogen, the carbon con. tent analyzed 0.03 pct. Some observations were repeated with hydrogen reduced cobalt compresses analyzing 99.9 pet pure. No significant variations in results were observed employing the as-received sheet, the remelted stock, or the cobalt compresses. Filings for X ray diffraction analysis were sealed in evacuated glass ampoules. Pyrex glass tubing was used for temperatures below (600°C and for higher temperatures clear fused quartz was satisfactory. After appropriate heat treatment at various ternperatures, the specimen ampoules were furnace cooled, air cooled or quenched by crushing under distilled water. This allowed a range of cooling velocities from less than one degree C per set to greater than 1,0oo°C per sec. X ray diffraction patterns were taken with a Debye camera and filtered characteristic cobalt K-alpha radiation. The of of the existing phases was roughly approximated by visual examina-

Jan 1, 1949

By Walter E. Hopper

(Wilkes-Barre Meeting, June, 1911.) I. LOCATION AND EXTENT. THE Caddo oil-field, shown in Fig. 1, is located in Caddo parish, northwestern Louisiana. The known producing territory of oil is covered by townships 19 N, 20 N, 21 N, 22 N, and ranges 15 and 16 W., shown in Fig. 2. The center of the field may be taken as Oil City, 24 miles north of Shreveport, on the Kansas City Southern railway. Shreveport is the second largest city in the State, and is the connecting point of five rail-road-lines. Drilling at the present time, however, is going on all over northern Louisiana, especially in Caddo and the neighboring parishes. II. HISTORY AND DEVELOPMENT. Natural gas escaping at the surface is found at numerous places in northwestern Louisiana. At Shreveport, the plant of the Shreveport Ice & Refrigerating Co. has been lighted by natural gas for 20 years. The well was drilled for water, but was abandoned on account of the gas. A test well, put down in 1905 near the western limits of Shreveport, was driven to 1,650 ft., and encountered indications of gas and oil at various depths, but did not succeed in finding enough to be profitable. Attention was first attracted to the Caddo field in 1895 by indications in water-wells from 40 to 60 ft. deep, in which the pressure of natural gas was noticeable. This indication of gas in a shallow well led to the drilling of the first well in the Caddo field, the old Savage Brothers & Morricell, or the Caddo Lake Oil and Pipe Line No. 1. The rig for this well was erected in May, 1904, and drilling began in June, 1904. The well was bailed Mar. 23, 1905, with a small amount of oil. It was deepened July, 1905, and converted into a "gasser " Jan. 3, 1906. It was abandoned January, 1907. In consequence of the finding of oil in the Savage well, drilling-operations were pushed with energy; and in April, 1905, four wells were drilling. Great trouble was experienced with

Apr 1, 1911

THE decades immediately before and after the end of the nineteenth century (1890-1910) were a period of increased activity in mineral industry education. One reason for this, undoubtedly, was the rapid increase in mineral production in the decade 1880-1890; pig iron and copper production tripled; coal, lead, and zinc output more than doubled. Most of the other mineral substances followed the same general trend. Aluminum production began in 1886; petroleum output, which in 1888 was less than it was in 1882, almost doubled in the next three years. Gold alone showed no appreciable change until its discovery at Cripple Creek in 1891, followed by the Klondike in 1896, brought to boiling a public interest in minerals that had been simmering for some years previously. The first cyanide plant in the United States was erected at Bodie in 1892, and the first chlorination plant at Cripple Creek* the next year. Silver- lead smelting had already greatly developed, and the metallurgy of copper was almost transformed. The hearth area and smelting capacity of copper reverberatory furnaces more than quadrupled between 1878 and 1894; matte converters were first erected at Butte in 1884. Copper production of the United States in 1899 was 20 times that of 1872. While it was the increased technology used in mineral production that really made the field attractive for educated young men, undoubtedly they did not realize that, and were impressed mainly by the quantitative increase in output. Another factor was the increased general interest in engineering education; three times as many men took engineering degrees in the United States in 1890 as in 1880; 1892 showed almost a 56 per cent increase over 1890. Industry had come to recognize that technical training was worth while. The mineral industry lagged somewhat at first; the total number of mining degrees

Jan 1, 1941

By James N. Orlich

Meridian Gold Company's Royal Mt. King mine (RMK), a subsidiary of FMC Gold Company, is located approximately 40 miles east of Stockton, California on the western edge of the historic mother lode belt. Gold ore at RMK is associated with a series of northwest trending fault zones hosted in either meta-volcanic or meta-sedimentary rock types commonly referred to as greenstone sulfide and carbonaceous phyllite. Mineralogy studies show gold in both ore types to occur primarily as electrum in the form of 1 -20 um inclusions in pyrite with varying amounts of free milling gold. In carbonaceous ores, gold was not found to be closely associated with carbon. At the start of the current mining operation, three major ore resources were identified. North Pit and Gold Knoll pits were the major greenstone reserves while Skyrocket Pit contained over 60% of the total reserves as carbonaceous ore. Since North Pit and Gold Knoll were to be the first areas mined, the mill began operation in February 1989 with a flowsheet designed for greenstone ores with a carbonaceous expansion anticipated after depletion of the greenstone reserves.

Jan 1, 1992

By G. L. Smit

The Buffelsfontein Gold Mining Company is situated in the Klerksdorp district of the Province of the Transvaal in the Republic of South Africa, approximately 100 miles west of Johannesburg. Gold production commenced in January 1957 and Uranium treatment of residue slimes as a by-product started in July 1957. The mining property is 5435 mining claims in extent, the equivalent of 7988 acres or 12.5 sq miles. The mine was initially exploited by the Pioneer Twin Shaft System, consisting of a 26-ft diam down-cast shaft and a 22 ft-diam up-cast shaft, sunk in the north-west area of the mine to cater for the hoisting and ventilation requirements for a milling rate of 150,000 tons per month. To exploit the Eastern zone of the property and assist in increasing production to 200,000 tons milled per month, it was decided to sink a further Twin Shaft System consisting of a 28-ft diam downcast shaft and a ventilation up-cast shaft -22-ft in diam, both monolithic concrete lined — 200 ft apart and 5300 ft deep. This paper deals with the sinking and commissioning of these Eastern Twin Shafts. This was achieved by one sinking crew within a period of 20 months. A) PLANNING 1) Siting: The Eastern Shaft System was sited in the north-east area of the property, 12,000 ft east on strike from the Pioneer System. (Fig. 1). Initially the system was sunk to the 5300 ft elevation to conform with the original Pioneer Shaft System. On completion a sub-vertical main shaft will be sunk to the 8000 ft elevation in the immediate vicinity, and subsequently the surface ventilation shaft will be deepened to this elevation by raising from level to level and sliping to full size. The exact positions of the shafts were chosen after: a) underground development had located certain known water bearing zones, and b) geophysical and topographical surveys had been carried out. The shafts passed through the following geological succession: Surface to 4430 ft - Dolomites of the Transvaal System 4430 to 4470 ft - Quartzites and conglomerates of the Black Reef Series of the Transvaal System. 4470 to 4470 ft - Diabasic Lava of the Venters-dorp System (Ventersdorp Contact Reef at base). 4470 to 5250 ft - Quartzites of the Elsburg Series of the Upper Witwaters-rand System. The shafts were sited to ensure that the least possible water would be encountered during sinking, and this contributed to the rapid rate of sinking. 2) Duties: a) The 22-ft diam ventilation shaft was designed to up-cast 1,400,000 cfm of air (0.060 density) against a resistance of 22 in. water gauge. b) The main shaft was designed to handle 160,000 tons hoisted per month as well as the men, material and down-cast ventilation to serve this tonnage. The 284 diam main shaft is equipped with streamlined buntons spaced at 15 ft centers set in pockets which were left during sinking. There are six compartments, four of which are sewed by two dual purpose hoists, hoisting either, twedeck man cages or 13-ton bottom discharge skips. The other two compartments are served by a single purpose winder hoisting double deck cages accommodating 60 men per deck. (Fig. 2). 3) Timing: Permanent equipment was ordered well in advance to insure continuity in the operation. Development underground reached the shaft positions before the start of sinking operations. From this development, boreholes were drilled into shaft positions to drain off water in the vicinity of the shafts. To ensure complete co-ordination of effort, all relevant data, as well as the allocation of responsibility, were made known to all persons and departments concerned. 4) Models: The extensive use of scale models during the preliminary planning stages proved most useful in deciding on design such as buntons, bunton pockets and guide cleats, and complex layouts concerning loading, spillage and pumping arrangements. (Fig. 3). These models also proved invaluable in determining the walling routine. Normal working conditions could

Jan 1, 1964

By N. O. Taylor

THE failure, by swelling, of several cast aluminum-zinc, spiral, pump rods, used to circulate water in a constant-temperature bath, brought up the question as to whether the presence of tin in varying quantities would have any appreciable influence in controlling this action. Previous workers had found the same difficulty with aluminum-zinc alloys, due to their swelling in water or solutions of electrolyte^.^ It was known that pure aluminum was practically insoluble in concentrated sulfuric and nitric acids, presumably due to the formation of an oxidized film on the surface. Concentrated sulfuric acid had little or no effect on pure zinc and tin and concentrated hydrochloric acid would attack all three metals. These facts aroused curiosity as to the probable reaction of the ternary alloys of these metals, and tests were made to determine their resistivity to the action of common laboratory reagents. Samples, covering the entire range of the ternary series of aluminum, zinc and tin alloys, were made up from good grades of the commercial metals.2 The materials were melted, at as low temperatures as possible, in graphite crucibles in a gas-fired crucible furnace. Graphite crucibles were used in preference to clay, to prevent the absorption of silicon by the aluminum, as found by previous workers. The melted materials were stirred thoroughly with pine sticks in order to ensure complete mixing and the greatest possible freedom from oxidation, and were cast in sectional, iron molds giving bars % in. in diameter and 5 in. long.

Jan 1, 1927

By Mohamed Elgouhary, Carol L. Tasillo, Daniel Koziol

"The Bolivar Dam, located near the Village of Bolivar, Ohio is one of a system of dams designed to provide flood control and water conservation in the Muskingum Watershed. The Bolivar Dam is a “dry dam” that only impounds water during flood events. In order to address problematic seepage, which negatively affects the structural stability of the dam, the U.S. Army Corps of Engineers (USACE) designed a partial-depth and partial-length Seepage Barrier Wall (SBW) through the upstream slope of the dam. For this project, TREVIICOS constructed a 36 in (914 mm) positive SBW by plastic concrete panel wall method and excavated using hydromill and clamshell equipment. The plastic concrete was manufactured on-site, which allowed for enhanced quality control and prompt service. This required the installation, commissioning and operation of a concrete batch plant on-site. This paper presents the challenging aspects of the design, manufacture and placement of the plastic concrete for the SBW in order to meet contract strength and permeability requirements as well as workability requirements necessary for tremie concrete placement.Project General InformationBolivar Dam is located in Northeast Ohio (Fig. 1). It is one of a system of sixteen dam projects designed to provide flood control and water conservation in the Muskingum Basin, which covers 20 percent of the State of Ohio (Fig. 2). Bolivar Dam is on Sandy Creek, a tributary of the Tuscarawas River.The Dam has been constructed, operated and maintained by the USACE, for the Muskingum Watershed Conservancy District. Its construction was completed in 1937 and it has been in operation for flood control since 1939.Bolivar Dam is a rolled earth fill dam, with a typical embankment section made of a central impervious core flanked upstream and downstream by a pervious outer shell with downstream rock toe. The embankment has a maximum height of 87 ft (26.5 m) and a crest length of 6,300 ft (1,920 m), and is comprised of the main embankment starting on the left abutment of about 1,500 ft (457 m) heading to the Northeast, followed by the terrace embankment of 4,800 ft (1,463 m) heading to the North. An upstream impervious blanket extends up to 500 ft (152 m) upstream of the dam along the majority of its length. The outlet works are to the left of the embankment, and consist of an intake structure with six gates, followed by two outlet conduits that finish in a stilling basin. To the left of the outlet works is the uncontrolled emergency spillway, which was doubled in width to 540 ft (165 m) in 1989, and excavated material utilized for construction of a stability berm against the upstream face of the main embankment. A concrete parapet wall was also installed along the upstream side of the crest during this work. In 1982, a toe drain, downstream filter berm and line of 35 relief wells were installed. The filter berm was recently extended an additional 200 ft (61.0 m) downstream and granular filters were placed over an approximate 2000 linear ft (610 m) reach of the lower terrace slope. (Fig. 3)."

Jan 1, 2016

By Giuseppe Granata

An innovative process using titanium tetrachloride (TiCl4) gas as reactant has shown successfully to obtain titanium through electro-winning of TiCl2 formed in-situ on titanium cathode. The process involves a continuous feed of TiCl4 gas reacting onto a titanium cathode immersed in a molten salt (NaCl-KCl), whereby in-situ formation of titanium dichloride (TiCl2) through a disproportion reaction. Simultaneously, the TiCl2, thus in-situ formed in the molten salt media, has been reacted into chlorine gas and titanium, the latest electrodeposited on the titanium cathode by electrowinning. The reaction kinetic of this innovative process was investigated in terms of TiCl2 in-situ formation rate and galvanostatic electrodeposition rate, where, in particular, the effect of operating variables such as TiCl4 partial pressure and flow rate, as well as temperature and galvanic potential applied was investigated.

Jan 1, 2014

By J. K. Horbaczewski

The reclamation of an open dragline pit (Pond A3P-2) at the Gibbons Creek lignite mine in east-central Texas required neutralization of acid mine pit water. At the start of treatment with hydrated lime (Ca(OH)2) on March 28, 2000, the pond had partially filled with 913,000 m3 (740 acre ft) of pH 4.9 water. Another 666,600 m3 (540 acre ft) of pH 3.3 water was pumped in from an adjacent pit (PitA3P- 1). By the end of the project (July 5, 2000), a combined volume of 1,579,000m3(1,280ac-ft or 417milliongal) in PondA3P-2 had been successfully treated to pH 8.2 with 431 t (475 st) of lime. This was two to three times more neutralizer than laboratory trials and detailed chemical titration had predicted. The main reasons for the difference are thought to be the inadequate representation in a laboratory setting of some of the chemical reactions that occurred in the field, including incomplete mixing of reactants, reactions with clay minerals in the pit walls, the kinetics of biologically-mediated reactions and the kinetics of aluminum oxyhydroxide polymerization (aging).

Jan 1, 2002

By Jiuhua Xu, Yuling Xie, Fenglei Bie, Neng Jiang

"Abstract - The Xiaoqingling Mt. area is one of the most productive gold districts in China. The gold-bearing quartz veins are controlled by a series of east-west shear zones within the Archean Taihua Group, and related to the late Yanshanian (Cretaceous) granite. The major metallic minerals are native gold, electrum, pyrite, galena, chalcopyrite and sphalerite, with gangue minerals dominated by quartz, sericite, ankerite, and calcite. The host rocks are mainly amphibolite, plagioclase gneiss, and migmatites. Principal alteration is sericitization, silicification, pyritization, and carbonization.There are four generations of hydrothermal quartz in altered rocks of gold deposits. The earliest generation of quartz, (Q1), occurs in altered amphibolite gneiss and migmatite, and typically contains fluid inclusions with halite crystals (type A) and two phases, (L+V), of fluid inclusions (type B). The salinities of type A inclusions are 32 wt% to 52 wt%, with dissolution temperatures of halite crystals being from 155°C to 465°C. The second generation of quartz, (Q2), occurs as a fine-grained aggregate associated with sericite, and has small (less than 3 µm) type B inclusions. The third generation of quartz, (Q3), occurs in mylonitic, intensively altered rocks and specially beresite (a type of rock composed of quartz, sericite, and pyrite) near the veins, and contains large amounts of CO2-rich fluid inclusions (type C-fluid inclusions with liquid CO2 and type D-fluid inclusion with high density CO2). The CO2 contents of type C range from 72.6 to 87.4 mol% in gas phases, and 35.7 to 68.3 mol% in liquid phases, based on Laser Raman analysis. The homogenization temperatures of fluid inclusion type A and C are from 215°C to 380°C, and from 210°C to 325°C, respectively. The minimum trapping pressure of fluid inclusions is estimated as 80 MPa to 170 MPa for type A, and from 57 MPa to 190 MPa for type C, which approximate to those of fluid inclusions in vein quartz.The ?18O of quartz are from 10.4‰ to 11.0‰ for Q3 of altered rocks, and from 10.7‰ to 12.8‰ for stage I quartz. The calculated ?18O of fluid inclusions varies from -1.3‰ to 6.0‰. The ?D of fluid inclusions ranges from -67‰ to -59‰ and from -81‰ to -48 ‰, respectively. It is concluded that the water in the hydrothermal fluids both reacting with wallrocks and precipitating orebodies could have been mainly of magmatic and/or metamorphic nature. However, local meteoric water might have been important in late mineralization, because of a distinct oxygen-shift toward the meteoric water. The ?34S values for pyrite of the ores range from -7.1‰ to +7.1‰, with an average of +2.9‰. Those of other sulfides (chalcopyrite, galena, and sphalerite, range from -12.5‰ to 8.3‰. The ratios of lead isotopes for galena of the ores are: 17.06 to 17.31 (206Pb/204Pb), 15.43 to 15.74 (207Pb/204Pb) and 37.58 to 38.45 (208Pb/204Pb). In summary, ore-forming fluids in the Wenyu-Dongchuang gold deposits may have originated from a mantle and/or lower crust source, and ore materials were derived from the Precambrian basement, the Taihua Group."

Jan 1, 1998

By G. G. Marino, J. W. Mahar

This paper provides an understanding of the behavior and potential damage of homes resulting from sag-type mine subsidence. This is done with extensive research of numerous case histories in Illinois collected by the authors. The house response to subsidence-induced ground displacements are summarized and evaluated. A damage level criteria, specifically developed for residential structures, is presented based primarily on repair costs. Damage levels and the associated subsidence profile characteristics for each case history are compared.

Jan 1, 1986

By Earl Bardwell

THE determination of suitable and safe annealing temperatures is one of the most important problems arising in the operation of a copper rolling mill. Certain of the larger mills have worked this problem out for themselves and in these mills the operation has become more or less standardized. In some of the mills pyrometers are used to measure the temperature of the annealing furnaces and careful watch is kept to see that overheating does not take place. In a considerable number of the mills, however, dependence is placed entirely on the judgment of the operator. The almost total lack of literature bearing on this subject seems sufficient warrant for the publication of this paper. The discussion of this subject naturally divides itself into two parts: (1) The effect of annealing temperature on physical properties; and (2) changes in the microstructure of refined copper due to cold rolling and annealing. I. THE EFFECT OF ANNEALING TEMPERATURE ON PHYSICAL PROPERTIES For the purpose of investigating this phase of the subject six test bars were selected, varying in oxygen content between the limits of 0.036 and 0.070 per cent. The chemical composition of each of these test bars was as follows:

Jan 8, 1914