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At the present time this plant is treating by direct cyanidation 1,000 tons of ore from Open Cut mining and dumps, and 1,200 tons of current flotation tailing obtained from the Sulphide Mill, per day.The following table shows the average analysis of the two feed products (see Table 1):Precipitation Process.-The pregnant solution obtained by the cyanidation of the above has the following general analysis:-Gold 0·600 dwt. per tonTotal Cyanide 0·050 %Free Cyanide 0·045 %Calcium Oxide 0·015 %KCNS 0·060 %Na2S20S 0·140 %CaS04 0·200 %Cu 0·050 %Zn 0·004 0/0K4Fe (CN) 6 NilThis solution, after standard clarification, is precipitated by means of zinc dust and a soluble lead salt.

Jan 1, 1939

1. Domestic Production and Use: In 1982, 13 companies operated 30 primary aluminum reduction plants, with 3 firms accounting for 55% of production. Washington, Oregon, and Montana accounted for 34% of the production; Texas, Louisiana, Missouri, and Arkansas 18%; Tennessee, Alabama, South Carolina, and North Carolina 14%; other central and eastern States 34%. Based on published producer prices, output of primary metal in 1982 was valued at over $5.5 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Packaging accounted for an estimated 39% of domestic consumption in 1982, transportation 20%, building 14%, electrical 8%, consumer durables 8%, and other uses 11%.

Jan 1, 1983

By Ralph Husack, J. W. Eckerd, G. A. Brady

The effect of gamma radiation on Pennsylvania anthracite and on reactions between anthracite and other materials was studied using a shielded , selfcontained 23,000 - curie cobalt 60 source . When anthracite was exposed to air at 65° C the reaction with oxygen was greater in the presence of radiation. than in its absence . Although drop- shatter tests indicated that exposure to radiation decreased the resistance to breakage of anthracite , this evidence of structural weakening was not supported by the results of grindability or particle- size studies . Irradiation caused definite changes in the gases evolved from evacuated samples of anthracite ; the percentages of hydrogen and carbon dioxide were increased, and the methane concentration remained unchanged . Carbon monoxide was evolved only from the unirradiated samples . Electron paramagnetic resonance (EPR ) measurements indicated large differences between evacuated samples and those exposed to air . There was little or no difference between irradiated and unirradiated samples , except that the free- radical content of unirradiated samples of anthracite increased progressively with higher temperatures of evacuation , but in the case of irradiated samples , no such behavior was found . Attempts to produce carbon disulfide and calcium carbide by reacting anthracite with sulfur up to 120 ° C , and with calcium oxide up to 400 ° C , were unsuccessful .

Jan 1, 1964

I. Domestic Production and Use: In 1981, 13 companies operated 32 primary aluminum reduction plants, with 3 firms accounting for 58% of production, Washington, Oregon, and Montana accounted for 32% of the total production; Texas, Louisiana, and Arkansas 16%; Tennessee, Alabama, South Carolina, and North Carolina 17%; other central and eastern States 35%. Based on published producer prices output of primary metal in 1981 was valued at over $7.5 billion. Aluminum consumption by 25,300 firms was centered in the East Central United States. Packaging accounted for an estimated 30% of domestic consumption in 1981, building 21%, transportation 18%, electrical la%, consumer durables 8%, and other uses 13%

Jan 1, 1982

By G. S. Hill

A large amount of the stereological error associated with liberation studies can he eliminated by assessing areas instead of linear intercepts. The presentation of a simple geometrical model as a stereological 'worst case' allows calculation of the worst possible grade/recovery curve for a given assemblage of areas. The true results are expected to lie in the window between this worst case and the hest possible case, represented by uncorrected data. The width of this window typically corresponds to an error margin of about 5% grade at a given recovery. An indication of where the data lies within the range of possible grade/recovery results may he obtained from a qualitative analysis of the locked section complexity. Assemblages consisting of texturally complex locked sections (ie. containing many mineral nuclei) are likely to exhibit minimal stereological bias and therefore will tend to lie close to the uncorrected side of the grade/recovery window.

Jan 11, 2011

By F. R. McDonald

This report presents a discussion of the spectra of 39 condensed thiophenes in which the structure includes at least 1 benzene ring. The vibrational bands present in three regions of the infrared spectra of these thiophenes were interpreted by comparing the similarities of the spectra of condensed thiophenes with the spectra of substituted benzenes. In the overtone-combination region 23 of the 39 condensed thiophenes had spectra which contained sufficient detail to be usable for correlating this region of the spectrum with the appropriate benzene spectrum. In the in-plane deformation region it was possible to make correlations for the vibrations of 18 of the 39 condensed thiophenes whose infrared spectra were studied. In the out-of-plane deformation region the C-H out-of-plane vibrations for hydrogen on benzene rings in the condensed thiophenes can be correlated using known data from substituted benzenes.

Jan 1, 1967

The value of processed materials of mineral origin was estimated to have exceeded $310 billion in 1990. U.S. raw nonfuel minerals mine production in 1990 was estimated at $33 billion, a 3.1 % increase over that of 1989. The value of minerals production increased in all but 3 of the last 30 years. The metals component of production value has fluctuated much more than the industrial minerals component. This reflects the greater volatility of metal prices. In 1990, total employment in metal mining continued the increase that began in 1987. This growth was partially offset by a slight decline in employment in industrial mineral mining, resulting in an overall in-crease of 1.1 % to 179,100 in 1990. Continuing high (by historical standards) metal prices led to expansions at some mines, as well as opening or reopening of additional mines, resulting in increased employment.

Jan 1, 1991

By R. V. Lundquist, H. Leitch

Two hydrated calcium aluminates , formed by side reactions in the leaching step and desilication step of the lime- soda sinter process , were investigated to better define their influence on alumina recovery . The two calcium aluminates , Caз [ Al ( OH) 6 ]₂ and зCa0.Al½ 03 · ( 8-12 ) H₂ ) , were prepared and identified by chemical and X- ray analysis . The relative proportions of each of these compounds formed in typical leach solutions at several temperatures were determined . The influence of free lime as a promoter of calcium aluminate formation was also investigated . The formation and precipitation from leach liquors of calcium aluminates contributes to the low alumina recoveries in the process . The presence of carbonate ion in the leach solution suppresses calcium aluminate formation and precipitation and results in higher alumina recovery . Hydrated calcium aluminates are formed in the aging of lime - soda sinters in the normal atmosphere .

Jan 1, 1963

The domestic mineral and material industry grew in some key sectors and declined in others during 1993; overall, the industry was poised at yearend for stronger growth in 1994. Metals production is expected to increase with anticipated growth in U.S. motor vehicle sales. There also may be increased demand for industrial minerals in 1994 based on domestic highway and building construction. Additional information on events, trends, and issues in the mineral and material industry is presented below and in the commodity sections that follow. Overall Industry Performance The value of processed materials produced from minerals in the United States during 1993 is estimated to have been about $326 billion, an increase of 5% compared with that of 1992. The estimated value of U.S. raw nonfuel minerals production in 1993 was $31.6 billion, about 1 % less than in the preceding year. The value of domestic minerals production has risen in 28 of the last 33 years.

Jan 1, 1994

By A. A. B. Douglas

In this paper the origins of the mortar intruded concrete concept and its development and application in the construction of watertight bulkheads in South Africa are described. The events leading to the commissioning and execution of the West Driefontein Experimental Plug and the Virginia/Merriespruit Boundary Plugs, and their roles in the proving of the technique, follow. The development of the first Transvaal and Orange Free State Chamber of Mines Code of Practice for Mortar Intrusion Concrete for Underground Plugs and Bulkheads, Johannesburg, November 1962,is explained. The saga of the October 1968 flood and subsequent salvage of the West Driefontein Gold Mine is recounted. The paper concludes with mention of the validation programme carried out for the Placer Dome Western Areas Joint Venture and their South Deep water barrier programme.

Jan 1, 2006

Real economic growth for 1988 may fall short of the 3.3% projected by the Department of Commerce in August 1988 because the summer drought and intense heat in many areas curtailed output more severely than expected. The economy grew at an average annual rate of 3.0% for the first three quarters of the year, slowing in the second and third quarters. Export growth, which occurred even as the dollar edged up compared with other industrial country currencies, was an important factor in the expansion. Notable gains were posted in sales of machinery, computers, aircraft, chemicals, and telecommunications equipment. Imports increased, but not as much as exports, and the U.S. trade position was still much improved from that of 1987. Personal consumption expenditures grew slightly faster than the economy as a whole. Purchases of consumer durables showed notable strength in the first half of 1988, but slowed down in the third quarter. Despite the moderate rise in interest rates, business spending for new plant and equipment also rose and contributed to 1988 gross national product (GNP) growth. Both new business investment and export demand spurred orders for U.S.-made machine tools. Orders for machine tools for the first 8 months of 1988 were almost triple those in the corresponding period in 1987.

Jan 1, 1989

The mineral Industry, following the economy as a whole, experienced little growth in 1992. However, with modernized plants, efficient workforces, and lower operating costs, the industry is well positioned to take advantage of possible improvement in the national economy during 1993. In addition to the significant 1992 events highlighted below, important events, trends, and issues within individual mineral industries are addressed in the commodity sections that follow. The value of processed materials of mineral origin is estimated to have been about $310 billion in 1992. The value of U.S. raw nonfuel minerals production in 1992 is estimated at approximately $32 billion, a 3% increase over 1991. The value of domestic minerals production has increased in all but 4 of the last 32 years.

Jan 1, 1993

U.S. demand for building and construction materials, such as construction aggregate, gypsum, and cement, remained strong in 1989. Cement imports declined slightly, representing about 17% of apparent consumption compared with 19% in 1988. Mexico, supplying 29% of the total, was the primary source of imports, followed by Canada with 21 %, Japan with 14%, and Spain and Greece with 10% each. Mexico was also the target of an antidumping petition, filed by producers in Arizona, Florida, New Mexico, and Texas, alleging that Mexican cement was being sold in these areas at less than fair value. This was the second petition filed against Mexico in the last 3 years. The International Trade Commission made a preliminary determination that the cement industry in these regions was materially injured by Mexican imports. U.S. demand improved for construction aggregate for the fourth consecutive year and was at a near-record level. The U.S. gypsum industry performed well, even though new housing starts decreased for the third consecutive year. Increased U.S. exports of gypsum wallboard and strength in the remodeling markets offset the impact of declining housing starts.

Jan 1, 1990

By W. S. Landers

Nine high-volatile bituminous Utah coals were carbonized singly and in blends with low-and medium-volatile bituminous coals. Of the 9 coals, 2 are in commercial use as the base coals in blends that produce industrially accept-able metallurgical coke, while 7 are regarded as weakly coking and are not used commercially in coking blends. The carbonization tests were made in a la-inch diameter, cylindrical retort, using 50-pound charges. Sunnyside coal blended with autogenous char generally produced larger and stronger coke than was yielded by straight Sunnyside coal. The volatile matter of the char and the concentration of the char in the blend appear to be important parameters influencing coke size and strength. A blend of 10 per-cent autogenous char of 7.2-percent volatile matter with Sunnyside coal yielded coke that was larger, stronger, and of higher apparent specific gravity than coke produced from an industrial coke oven blend consisting of 15 percent medium-volatile coal and 85 percent Sunnyside coal.

Jan 1, 1967

By Clarence A. Wright, JAMES T. NORTON, JAMES G. PARMELEE

The object of this paper is to give to mining companies and to all others who are interested some idea of the possibilities in the treatment, by differential flotation, of lead-zinc ores of the Coeur d'Alene region and other districts. The purpose of these investiga.. tions is not to evolve a differential flotation process that would replace present methods of gravity concentration but rather one that could be applied to the relatively fine material and slime produced in the mills and treated unsuc_pessfully by gravity methods or by flotation. It is expected, of course, that the products to be obtained by differential flotation would be of much better grade than those now produced by flotation in the Coeur d'Alene mills. In view of the fact that it has been difficult to obtain representative samples of flotation feed from the mills, owing to the necessity of shipping the material wet and free from oil or other foreign matter that might be deleterious to the differential separation of the sulphides, the writers have felt justified in running flotation tests with the mill feeds in order to ascertain whether a differential separation of the sulphides could be effected. However, two different lots of flotation feed were tested for differential flotation, and the results of tests of one of these are given in this report. It is hoped that it will be possible later to test out the flotation feed for differential flotation on a large scale in some of the mills. This paper covers part of the investigations carried on by the United States Bureau of Mines in cooperation with the Idaho Bureau of Mines, the University of Idaho, and certain mining companies of the Coeur d'Alene region. Although the results of the tests included in this report are not to be considered final, they indicate possibilities and may suggest others leading to a solution of the problem of separating lead and zinc sulphides by differential flotation in the treatment of certain ores.

Jan 1, 1921

The U.S. economy continued to expand during 1986, although at the slowest pace since 1982 when the current business expansion began. Real gross national product (GNP) grew about 2.6%, slightly below 1985 growth but significantly below that of 1984. The continuing expansion was fueled predominantly by rising personal consumption expenditures as well as growing government purchases of goods and services. Fixed investment, although positive, failed to grow at the rate of the overall economy. The trade deficit, which increased more than 30% over the record 1985 level, continued to depress economic growth despite significant declines in the price of petroleum and the value of the dollar. On a more positive note, domestic employment continued to grow--increasing over 2 million from the 1985 level--and inflation and interest rates declined. The unemployment rate dropped slightly to 7.0%. Of direct importance to the minerals-producing industries, expenditures for consumer and producer durables as well as investment in residential construction each grew faster than the overall economy, but investment in nonresidential structures fell more than 10% from the 1985 level. The low level of real capital spending declined about 3% in 1986, following strong gains in 1985 and in 1984. Capital expenditures for new plant and equipment bottomed out in the second quarter and expanded in the third and fourth quarters. The decline in the first half of the year was partially attributed to uncertainty arising from the then-proposed tax bill. Also, there was little impetus for corporations to invest in new capacity since factories were operating at less than 80% of capacity during most of the year, in part because of continued competition from imports.

Jan 1, 1987

By D. A. Reynolds

THIS REPORT gives results of an investigation of the carbonizing properties of two Tennessee coals, one from the Jellico bed in Campbell County and the other from the Sewanee bed in Marion County. Jellico coal and blends with 20 and 30 percent Pocahontas No. 3 coal were carbonized at 800° and 900° C. by the BM-AGA method. Sewanee coal was carbonized by the same method at 800°, 900°, and 1,000° C.; blends with coals of similar and different ranks were carbonized at 800° and 900° C. The coals were subjected to various physical and chemical tests, including complete chemical analyses, low-temperature assays, and agglutinating, free-swelling, friability, plasticity, and expansion tests. The Tennessee coal field is a part of the Appalachian field, which extends from northern Pennsylvania to central Alabama. The Jelico bed, one of the most important in the State, is part of the Jellico formation, which is above the Lee formation of the Lower Pottsville. Sewanee coal bed belongs to the Sewanee conglomerate and is stratigraphically lower than the Jellico bed.

Jan 1, 1953

By George C. Branner

This circular is concerned with eight nonferrous scrap metals as they generated, collected, prepared, and consumed in California. Brief reference also is included with respect to Nevada and Hawaii. Four of these scrap metals - copper, lead, aluminum, and zinc - are of major importance and make up about 95 percent of the total value, whereas the remaining four - antimony, magnesium, nickel, and tin - make up the remaining 5 percent. For convenience, the subject matter is divided into three parts, (1) Data with respect to the collection, preparation, and marketing practices that are common activities to all the nonferrous scrap metals; (2) separate discussions and statistical data with respect to each of the eight nonferrous scrap metals in California; and (3) data with respect to Nevada and Hawaii.

Jan 1, 1962

By Milton Blander

"A review of concepts and theories for predicting thermodynamic solution properties of multicomponent high temperature liquid solutions is reviewed. During the last 50 years the ability to predict such properties for molten salts, silicates and metals based on the generally known properties of the lower order (often binary) systems has been developed and shown to provide predictions which are quite useful in science and technology. There are many gaps in our understanding of these high temperature solutions, especially for metals, and considerably more work is needed.INTRODUCTIONA number of solution theories and concepts have been developed which reliably predict the properties of multicomponent solutions from those of the lower order systems (often only the binaries). Because there is available data for a large fraction of the important binaries, the capability for making predictions for many multicomponent systems used in metallurgical separation processes is broad and potentially very useful. At the very least, the theories greatly minimize the data necessary for predicting properties of complex multicomponent solutions of molten salts, silicates and metals. It is the purpose of this paper to discuss the concepts which are demonstrably useful. We will discuss simple forms of the theories to make the concepts clear but we will refer to the publications which contain the more complex equations needed to treat the large majority of systems.A simple framework for understanding what we need to know in order to make technologically useful predictions is based on well known thermodynamic principles. In technologies and sciences where molten salts, slags magmas or molten metals are used or studied, one must often calculate the extent of a chemical reaction (or separation) or of phase changes. To do this, one must first write an equilibrium constant, K, for the reaction in terms of the standard free energy change of the reaction, ?G°."

Jan 1, 1996

By L. Ziyuan, S. Chunbao, K. Jue, H. Yang, S. Tichang

In this study, potassium ferrocyanide, a non-toxic cyanide precursor in dark and diffuse reflection environments, was applied as a reagent for the leaching of gold. The free cyanide ions were gradually released from the potassium ferrocyanide solution under the ultraviolet light. Orthogonal leaching experiments were performed in gold ore to analyse the effect of solution pH, potassium ferrocyanide dosage, and temperature in potassium ferrocyanide solution system under UV light. Response surface methodology (RSM) was applied to explore the role of potassium ferrocyanide in gold leaching, Optimised results showed that the gold recovery reached 67.74% in a high-alkaline environment at a 12.6 pH, 3.8 kg/t potassium ferrocyanide dosage, 62°C, and irradiance of 10mW/cm-2. The gold leaching kinetics was monitored by quartz crystal microbalance with dissipation (QCM-D) of potassium ferrocyanide solution. The results indicate that the gold extraction process consists of two processes: adsorption and leaching, and a rigid adsorption layer formed on the reaction surface. Furthermore, Xray photoelectron spectroscopy (XPS) analysis of the gold sensor surface after leaching reaction showed that -C≡N appears on the gold sensor surface, and the gold is oxidised to form AuCN complexes. Keywords: Gold leaching, potassium ferrocyanide, UV light, QCM-D, AuCN complexes

Jan 1, 2020