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By Reinhardt Thiessen

"INTRODUCTION Coal is a complex substance consisting of many different constituents representing many chemical compounds, very few of which are known. It is homo genetic, however, in that it is derived almost entirely from plants. But plants as a whole are complex, being composed of a large number of tissues, each consisting of a large number of cells in a great number of arrangements and composed of a number of chemical compounds in great variety of proportions, and enclosing a large number of waste products representing a large number of' chemical compounds as cell contents. Coal should therefore be expected to be a very complex substance.That coals are formed from plants is no longer debated, but the manner in which coal was formed from the plants leaves many problems still unsolved. However, in general it is now conceded that all coals of all ranks and ages had their origin in deposits completely analogous to our peat deposits of today and that coal formation is a process that runs through the whole series, beginning with peat, and through, the various ranks of lignite, subbituminous, high-, medium-, and low-volatile bituminous, semianthracite, and anthracite in a related chain. In the study of coal, it is therefore of the utmost importance to study and to know not only the plants contributing but .also the manner in which they are transformed into the substances forming the deposits. It is therefore of the greatest value to review briefly the formation of :,eat as it is known today, and to inquire into the facts as to what plants contribute to peat, what parts and products prevail, what are the chemical compounds that enter and which prevail."

Jun 1, 1947

Australian coals tend to be young in geological age and high in ash by world standards; preparation of the coal before marketing is almost universal. On the basis of float and sink data from 39 locations in the Eastern Australian coalfields, the coals are placed in four categories representing increasing difliculty in their washability characteristics. These seem to be related neither to the geological age nor the geographical position of the deposit and Hunter Valley coals, for example, span all categories. The influence of crushing on the washability of Australian coals is briefly considered and from limited data it is concluded to be appreciably smaller than for British or North American coals. A strategy for the float and sink analysis of Australian coals is proposed and the influence of washability characteristics on current trends in the selection of separating processes for coking and steaming products is discussed.

Jan 1, 1979

Jan 1, 1988

By O. C. Garst

"The lightness and relatively high strength per unit weight of certain magnesium alloys have interested designing engineers for many years. Ever since the noted investigator Bunsen3/ first produced the element by electrolysis of the fused chloride in 1852, utilization of this light metal has been considered. Magnesium is widely distributed over the earth's surface in high-grade as well as low-grade deposits; it occupies eighth place in the list of elements arranged in order of their decreasing abundance, as there is 2.24 percent magnesium in the earth's lithosphere. Even though the element is distributed widely in the form of relatively insoluble: minerals and also as soluble salts in sea water and spring water, as well as being an indispensable constituent of plants and animals, the technology of magnesium was slow development. This slowness of development was first caused by confusion or the part of the early investigators who thought that magnesia, magnesite, magnetite, and the pyrolusite-type manganese ores were compounds of the same metal. At one time the metal that we now know as manganese was called magnesium, and magnesium was called either magnium or talcium. In addition to this coon, the chemical activity of the metal, especially at high temperatures, created problems that are still difficult to solve.With the advance of science in all branches, .methods for -he production of magnesium were developed. The methods first used for producing the element were: (1) reduction of magnesium salts with alkali metals,4/ (2) electrolysis of aqueous solutions of magnesium salts, and (3) electrolysis of fused magnesiun salts.The first attempts to produce magnesium by the carbothermal reduction of magnesia were failures as sufficient thermodynamic knowledge concerning the reversibility of the reaction between magnesia and carbon was not at hand. As the igneous electrolytic Method for making the element was more easily controlled than the others and. yielded more metal per unit of energy, considerable work was expended on the improvement of this process. The work in this field paralled that on the electroreduction of aluminum and the alkali metals. For several years the entire magnesium industry was dependent on this igneous electrolysis process for its supply of the metal, but as demand for the metal increased and more scientific knowledge was available, other processes were developed. Today magnesium is produced by the electrolysis of molton magnesium chloride electrolytes, the carbothermal reduction of magnesia, in arc furnaces followed by shock cooling of the furnace gases by a coin inert atmosphere, and the silicothermal reduction of calcined dolomite in stainless steel retorts."

Mar 1, 1946

By F. Habashi

The pioneer work on pressure hydrometallurgy was conducted in Russia at the end of the nineteenth, and the beginning of the twentieth centuries, by Karl Josef Bayer (1847-1904) and Vladimir Nikolyevitch Ipatieff (1867-1952), both working independently in Saint Petersburg. Bayer was studying pressure leaching while Ipatieff was studying the precipitation of metals and their compounds by hydrogen under pressure. Gradually, industrial applications took place first in the aluminium and later in the nickel industry. Today, the technology is well established in a large number of industries, such as uranium, gold, zinc, titanium, tungsten, and more recently copper.

Jan 1, 2004

By W. Vickers

SALKOVITZ1 has given a number of useful angles between planes for use with the Laue method in determining the orientation of bismuth single crystals. Bismuth is usually considered as having a face-centered-rhombohedra1 structure with its axial angle 87°34', Fig. 1. A similar figure given by Sal-kovitz appears to be in error in that the angle there marked as 87°34' should be 92°26. The primitive cell is a single rhombohedron of axial angle 570 14. The structure is almost face-centered-cubic and hence high accuracy in measurements is essential if there is to be no confusion in indexing poles or zone axes. It is easier to get this accuracy if zone axes are plotted on the stereogram because they will lie near the basic circle where the net has a more open scale. The zone axes can be read from the film, using a Greninger chart, and can be plotted more accurately than poles. Also, the angles between points near the basic circle can be read more accurately than those between poles near the center. In order to use the zone axes the angles between directions have been calculated from a formula given by Niggli,2 and are given in Table I. Miller indices

Jan 1, 1958

By Guihong Han, Duo Zhang, Yanfang Huang

Ni2SiO4 was prepared by chemical precipitation process as a novel anode material for lithium-ion batteries. The structure and morphology of further annealed Ni2SiO4 samples were characterized by XRD and SEM analysis. The electrochemical performance including cyclic voltammetric curves (CV), electrochemical impedance spectra (EIS), charge/discharge curves and cycling performances were also determined. The results demonstrated that the crystal structure of the samples is orthorhombic having space group Pmn21. The morphological structure of materials exhibited cubic particles with sizes in the range of 50–80 nm. The first cycle charge capacity of the pure Ni2SiO4 particles reached to 753 mAh g−1 with the coulombic efficiency of 63.8%. The charge capacity remained 305 mAh g−1 at a current density of 100 mA g−1 even after 50 cycles, which is nearly 208% higher than those of the Ni2SiO4 with SiO2 impurity. Ni2SiO4 can be a promising alternative anode material.

Mar 1, 2018

The value of processed materials of mineral origin was estimated to have exceeded $297 billion in 1991. U.S. raw non fuel minerals production in 1991 was estimated at $30.8 billion, a 5.8% decline from that in 1990. This estimate was based on data for the first quarter of 1991 (in some cases two quarters) for most of the 21 minerals that for many years have accounted for more than 95% of the industry's production value. The value of minerals production has increased in all but 4 of the last 30 years. The metals component of production value has fluctuated much more than the industrial minerals component, reflecting the greater volatility of metal prices. Employment in metal mining rose slightly in 1991, but this gain was more than offset by a decline in employment in industrial mineral mining, resulting in an overall decline of 3.0% to 164,600 workers in 1991. Prices of several major metals declined during 1991, reflecting weakness in the economy, causing some metal mines to shut down or reduce operations.

Jan 1, 1992

By W. W. Roepke

The Bureau of Mines has developed an interactive computer program that enables mine operators and others to identify the effect of cut-ting system changes on relative dustiness at the face. The program, which simultaneously evaluates machine parameters, coal seam parame-ters, and operator-controllable parameters, was developed for use on any microcomputer using BASIC programming language. The program allows the user to change one or more of the cutting system parameters at a time to see how these changes affect relative dustiness. A complete program listing and flowchart are included along with operating in-structions and sample outputs. An example showing how to use the program is also included.

Jan 1, 1985

By J. Trow

Dowsing is really IESG which inductively locates electric gradients (dv/dx) on the flanks of SP anomalies. "Sensors" are in one?s head. The "meter" consists of one?s body, limbs, and two $.69 welding rods. The method was calibrated near Mamainse Point, Ontario, where IESG-negative chalcopyrite-bornite-chalcocite-native copper ores reveal mineral zoning related to the IESG-positive Keweenaw fault, down which oxidizing solutions moved. In Michigan, the IESG-positive Keweenaw fault suggests that oxygen-bearing solutions from the Jacobsville Sandstone moved downward to oxidize hydrothermal sulfur to produce native copper, and to supply sufficient water to satisfy Walter White.

Jan 1, 1992

By Courtney A. Young

Cyanide is a fast-acting, highly toxic substance but, at the same time, is deemed essential for sustaining life as well 'as our standard of living. In this manuscript, the facts about cyanide are presented beginning with a brief history and definition and ending with a discussion on cyanide alternatives. Other topics include speciation, physical characteristics, toxicity, manufacturing, cyanogenics, cyanide cycle, separation, destruction, and markets including those outside the mining industry. Emphasis, of course, is placed on gold production by leaching and how it is influenced by ore type, mineral characteristics and economics as well as its advantages and disadvantages.

Jan 1, 1998

By Jo Katembo, Patty Bwando, Patient K. Ilunga, Yves Kalubi, Emman Mulaj

"From 2010, the dolomite concentration in the ore fed to the Usoke Plant increased, resulting in a significant increase in the gangue acid consumption and Mg build-up in the circuit, and thus an increase in the Mg:Co ratio in the plant solutions. This affected the Co salt grade, reagent consumption, filtration and drying capacity. Efforts were put in place to minimise the acid consumption and consequently the Mg dissolution (such as use of pre-diluted acid), but the benefits were negligible. Various efforts were then initiated by CHEMAF to improve the cobalt plant productivity (quantity and quality) by process changes, dual precipitation and seed recycle. The positive results obtained in the laboratory were successfully implemented on plant scale. A change in the process from a single-stage precipitation with Na2CO3 to dual precipitation using a combination of Na2CO3 and NaOH improved the capacity of the Co salt filtration by 30%, the Co salt grade and drying capacity by 50%, and reduced the reagent consumption by 22%. Implementation of precipitate seed recycle increased Mg rejection by 40%, improving the Co salt grade from 20% to 25%, and yielding a further drop in reagent consumption. INTRODUCTION CHEMAF (Chemicals of Africa), a mining company located in Katanga province of Democratic Republic of Congo (DRC), has been operating since 2003. The Usoke hydrometallurgical plant treats the Cu-Co ore from the Etoile pit to produce Cu cathodes via a leach–solvent-extraction (SX)–electrowinning (EW) circuit and Co salt via a selective precipitation process. The plant was designed to treat run-of-mine (ROM) ore grading 6% Cu and 1.5% Co; but, in 2008, due to a decline in grades, a heavy-media separation (HMS) plant was commissioned to enrich the low-grade ROM (3.5% Cu and 0.5% Co) up to 8% Cu and 1% Co before feeding it to the hydrometallurgical plant. Co is recovered by precipitation of Fe and Al with limestone, followed by Co precipitation as Co carbonate using sodium carbonate (Na2CO3), also known as soda ash. 85% of the final effluent from cobalt precipitation is recycled back to the plant as process water; the balance, 15%, is bled out and compensated for by fresh water top up to control and retard the rate of sodium sulfate build up."

Jan 1, 2015

By F. W. Bradley

GOLD is a large subject. One could talk about its geological or mineralogical occurrences, prospect- i11.g for it, mining of .it, its metallurgy or its marketing; but I have decided to limit my discussion to gold as a business-that is, to its production and marketing. In the production of gold, it is necessary to consider the many possible sources, the quantities available, the capital and operating costs and the chances of price-breaking competition. So in the following remarks I shall endeavour to point out that though gold is found in every formation constituting the earth's crust, though it is possible to-find it free in great concentrated placer deposits on the surface, though there are still large unprospected areas of both the surface and the crust, though it may be possible to produce it by the cheapest labor on earth, and by processes not as yet developed, it still has an unlimited market at a definite price. There is no reasonable fear of disturbance by the finding of bountiful deposits, or by cheapening the cost of production due to devaluation, or by the development of any easy processes for direct, or for by product, production.

Jan 1, 1932

By H. Z. Kuyumcu

Associated with the development of a novel microbiological oxidation process for the conditioning of iron hydroxide slurries from ferrous mine waters, there is a realistic chance to make the contained iron available for a material utilization. The transformation of ferrous into ferric compounds is coupled with the precipitation of iron hydroxisulphate mostly in terms of the mineral Schwert-mannite. The further treatment of the iron hydroxisulphate has to be aimed on the processing for product recovery and product refinement. For many potential applications, e.g. in the ceramic industry, the pigment industry or for metallurgical applications, the removal of sulphate is essential. For the dehydration of the iron hydroxisulphate and the sulphate removal, microwave heating technology is a beneficial method. In contrast to conventional thermal heating processes the supply of energy in microwave application takes place directly within the material through the dissipation of electromagnetic energy, i.e. no heating medium is needed. It is a volumetric heating process regardless of the surface of the material. The rapid and targeted energy supply and the good controllability of microwave heating systems are advantages which have led to a wide variety of applications in industrial processes. Among the diverse use for heating of temperature-sensitive, chemical and pharmaceutical products as well as foodstuffs the number of applications also in mineral and solid processing increases. At the Department for Mechanical Process Engineering and Solids Processing of the Technical University Berlin the use of microwave technology for the treatment of iron hydroxisulphates has been investigated systematically within the framework of a cooperative research project. The paper at hand shows results from material conversion tests subject to a variation of the relevant process parameters. The reaction products are characterized and the process is compared with the conventional heating in a rotary kiln.

Jan 1, 2014

By John D. Bardill

A cooperative project between the Bureau of Mines, Department of the Interior, and the Montana School of Mines, investigating results of hydraulic systems for transporting sand slurries for emplacement, was begun in August 1955. In such circumstances, the Bureau provides funds for a fellowship leading to a Master of Science degree as well as available instruments, tools, supplies and equipment. The School provides the ore-beneficiating laboratory with its equipment for use as a pilot plant. The success of a hydraulic backfilling method employing mill tailings depends largely upon the physical characteristics of the tailings. One of these characteristics is size distribution, especially in the finer size ranges. When being emplaced underground, almost impervious layers of slimes separate from some types of mill tailings containing a high percentage of slimes and settle on the top of the sand fill. These coatings may be so dense that the water in the slurry cannot percolate through them for proper drainage. Successive layers of fill in a stope, each with an impervious coating on top, sometimes build up a hydrostatic head, creating pressure on the bulkheads. This may cause breaks in the lining material, inducing sand runs and flooding the level and sumps below. Deleterious slimes flocculated and disseminated throughout the sands should help prevent the formation of impervious slime layers, increasing percolation and settling rates.

Jan 1, 1960

By Henry Kreisinger, WALTER T. RAY

In its investigation of more efficient methods for utilizing the coals and lignites in the United States, to the end that waste might be avoided, the value of low-grade coals increased, and the life of the nation's fuel resources prolonged, the technologic branch of the United States Geological Survey carried on a study of the factors involved in the manufacture and use of briquets, including the suitability of various coals for briquetting, the cheapest and most satisfactory binders, and the furnace behavior and evaporative efficiency of briquetted fuel. The investigations had their beginning in the work done at the coaltesting plant at the Louisiana Purchase Exposition, St. Louis, Mo., in 1904, and were continued at St. Louis and later at Norfolk, Va. Accounts of various tests and statements of the conclusions to be drawn from them have appeared in a number of bulletins. a In connection with the work at Norfolk, comparative steaming tests were made in stationary, marine, and locomotive boilers with run-ofmine coal and the same coal formed into briquets of two sizes. The tests in a locomotive boiler that are described in detail in this bulletin were undertaken to add cumulative evidence to work done at other places. They were made possible through the courtesy of the Seaboard Air Line Railway Company in supplying both the locomotive and the coal used. During the trials the locomotive stood on a side track in the shop yards of the railway company at Portsmonth, Va. No running tests were made.

Jan 1, 1911

By ABBOT A. HANKS

WHEN gold was discovered in California, and San Francisco grew almost over night from a handful of people to many thousands, one of the first difficulties experienced was the lack of money. Gold dust in considerable quantities was rushed into the city from the various mining camps but there was no money. Purchases were paid for by weighing out dust in hand scales. We can appreciate' the difficulty of paying for a drink or buying a postage stamp under these conditions. All this gold was in the form of dust from placer workings and the first metallurgists were the assayers' who melted and refined this gold, casting it into bars which were weighed, assayed, stamped with fineness; value, and the name of the assayer. Many .of these plants were of considerable size, handling shipments that were accumulated by banks and express companies throughout the "Diggings" and sent to San Francisco to be shipped by water to the eastern states. Several

Jan 1, 1931

By D. du Plessis, R. Stobbs

The Canadian Clean Power Coalition (CCPC) was created in 2001 to protect and enhance Canada’s vast coal and other carbon-based resource wealth, and to ensure that environmental public policy decisions recognize that these resources are a Canadian asset, not an environmental liability. To achieve its mandate, CCPC has undertaken to demonstrate technologies for use in new coal-fired power plants to control air emissions including carbon dioxide (CO2), nitrogen oxides (NOx), sulphur dioxides (SOx), mercury (Hg), and particulates (PM). The first phase of the demonstration project assessed three existing technologies for coal-fired power plants that reduce all emissions, including CO2, to levels equivalent to or below that of gas-fired power plants. The technologies considered in this phase included integrated gasification combined cycle (IGCC), ‘oxyfuel’ combustion, and amine scrubbing of pulverized coal. These technologies were evaluated with three coal types: Eastern bituminous, western sub-bituminous, and lignite coals. This paper presents the studies, conclusions concerning the capital and operating costs of these technologies, the cost of electricity produced (with CO2 removed), and the cost per tonne of CO2 avoided. It also discusses the potential for using captured CO2 for enhanced oil recovery, and possible technology enhancements for improving the competitiveness of gasification of low-rank western Canadian coals. The second ongoing phase of CCPC’s work includes the design and construction of a commercial-scale plant to demonstrate the feasibility of integrated gas combined cycle (IGCC) and/or polygeneration technologies and the potential for using the CO2 generated for enhanced recovery of conventional oil.

Jan 1, 2006

By Georgene Renner, Chee Theng, William Gleason

"In February 2018, drawn in part by the states’ proud mining heritage, SME took its Annual Conference & Expo to Minneapolis, MN for the first time. More than 5,000 people and 554 exhibitors converged on the Minneapolis Convention Center for three days of networking, exhibiting and technical sessions.The state’s mining legacy, one that continues today, is fueled in large part by its vast iron ore resources in the northern part of the state. The historical significance of the mines in the Mesabi Range, otherwise known as the Iron Range north of Lake Superior, cannot be understated. “Mining is a way of life here,” said U.S. Congressman Rick Nolan of Minnesota’s 8th Congressional District. A native of the Iron Range, the three-term U.S. congressman was one of the featured speakers of the opening keynote session. “We like to think we contribute enormously to the well-being of this country and the world. We were the source of the iron ore and steel that helped win two world wars. And we like to think that we are part of the progress that has taken place in the United States ever since.” Nolan kicked off the keynote sessionthat focused on innovation and its part in the mining industry. The session included Rene Aquilar, vice president of corporate affairs and sustainability, Antofagasta Minerals Group; Bob Anderson, vice president for research and development, 3M; Rolf Weberg, executive director, Natural Resources Research Institute, University of Minnesota-Duluth and Christopher Beck, executive vice president and president, Nalco Water. The panel session looked at U.S. and global minerals production, and the importance of the United States to maintain a major role in the minerals industry, both as a producer and as a technology leader. The panel also touched on the global mining industry and the issues that impact mining around the world. Sustainability, the use of water in mining and earning a social license to operate were among the topics discussed by the panel.Speaking of the importance of mining, Nolan conceded that talking about the benefits of mining to the crowded auditorium at the SME conference might be akin to a preacher speaking to the choir, but, following the adage that all politics are local, he continued to illustrate his point by emphasizing the importance of mining to the Great Lakes.“A study by Homeland Security concluded that 13 percent of the nation’s GDP comes out of Lake Superior through the locks at Sault Ste. Marie and most of that is iron ore,” said Nolan. “That study found that, if those locks fail, it would create a national depression. It would put millions of people out of work. That ore and those minerals supply the steel mills, the auto industry, the heavy industrials. They are the heart of our economy. The study concluded that if the states that make up the Great Lakes were a nation, it would be the fourth largest economy in the world.”"

Jan 5, 2018

Five watersheds, ranging in size from 29 to 49 acres, were selected in East-Central Ohio to investigate the hydrologic and water quality conditions occurring before, during, and after surface mining. Four of the watersheds will undergo surface mining, involving either the Number 6, 9, 11, or 8 coal seams, and one watershed having an outcrop of the Number 6 coal will be operated as a control watershed. To determine the premining hydrologic and water quality conditions (Phase 1), physical information was obtained for each watershed and instrumentation was installed for obtaining hydrologic data and water quality samples. In addition to topographic maps, soils and vegetation maps were prepared. Stratigraphic columns were developed from geologic cores; networks of observation wells and of soil moisture access tubes were installed; and weather stations were established to measure temperature, humidity, wind and solar radiation, and to collect precipi¬tation samples. Field data were collected over a 10-month period for one watershed and for about 8 months on another watershed before surface mining began. The other watersheds continued in the premining data phase. These data were for precipitation, temperature, relative humidity, wind speed, solar radiation, snow and frozen soil, soil moisture, infiltration (rainfall simulator), spring discharge, runoff from watersheds, and ground-water levels. Also, samples of runoff and ground water were obtained for chemical analyses and additional samples of runoff were acquired for suspended sediment load determinations. Over the study period, precipitation was not very representative of the long term averages, but data are available from the control watershed for a representative 7 year period which should prove invaluable in modeling the hydrology of the project watersheds for the premined conditions. Spring discharges (before mining) from the upper aquifer of two of the watersheds averaged only 508 and 652 gallons daily. The proportion of precipitation occurring as surface runoff from the large watersheds ranged from 8 to 36 percent and the peak discharges from 5.86 to 81.95 cfs. Base-flow and runoff water samples from four of the watersheds (unmined conditions) were collected and analyzed quantitatively for 39 water quality parameters. Monthly precipitation samples sediment fractions of the base flow and runoff were analyzed for 22 and 17 parameters, respectively. The average concentrations of the water quality parameters for the watersheds (unmined), except for suspended solids, were as low or lower than the EPA recommended maximum allowable concentrations in drinking water. Several parameters in precipitation equaled or exceeded the levels of corresponding parameters in runoff water. The average concentration of suspended solids in storm runoff ranged from 118 to 1110 mg/l, and for base flow the range was from 44 to 247 mg/l; the higher concentrations were associated with the watersheds exhibiting the greatest disturbance. Iron ranged from an average of less than 3 µg/1 to 228 µg/1. Manganese ranged from less than 41 µg/1 to 334 µg/I. Ground-water systems (unmined condition) are described for the five project watersheds. Each watershed was found to have two major perched aquifers within the top 250 feet. Generally, these perched aquifers involve local flow systems, though flow across watershed boundaries in some areas. Recharge is mostly from local precipitation and discharge is mostly as spring flow, base flow, evapotranspiration, and leakage through the underlying confining bed. Shallow ground water was commonly of the calcium bicarbonate type. Although dissolved-solids concentration was generally 200 to 600 mg/1, brackish or salty ground water was present in several areas. A composite hydrologic model for the project watersheds will consist of separate ground-water, unsaturated flow, overland flow, and evapotranspiration component models. The ground-water model (a modified quasi-three--dimensional U. S. Geological Survey model) operates on a grid network and the newly formulated unsaturated flow model was divided into overlying prismatic elements for numerical solutions. The unsaturated flow model includes provision for incorporating the evapotranspiration model. An available distributed kinemetic overland flow model was utilized. An analyses was made of one of the costs of reclaiming coal mines; the legal and administrative costs of complying with legislation. Such costs borne by coal companies under the Ohio law are thought to be a surrogate of these costs under the new Federal law. Regression analyses were used to relate the legal and administrative costs to acres in the permit and the tonnage of coal produced.

Jan 1, 1978