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By S. Kraemer

Consumption of plastics has been growing in both the U.S. and world markets since the mid-1930s. This growth is due to plastics being used to make new products and as a replacement material for existing products. This paper develops an understanding of the replacement process by looking at the use of plastic, specifically PVC, in the construction pipe industry. History details the growth of the plastics industry and a discussion of the material selection process indicates the advantages and disadvantages of plastic pipe. Analysis shows that the use of plastic, as an alternative material for pipe, is having a significant effect on the cast iron, copper, clay, and steel industries. For the purpose of understanding the replacement process, three example residential systems were examined with a lifecycle cost analysis being performed. PVC was the material of choice in 1988 for all systems. Even though disposal cost was the one area where PVC was not the most cost effective, disposal costs were not sufficient to offset the overall advantage of using PVC on an economic basis. That plastic competes effectively with other materials, in terms of material properties and cost, indicates that further work should be performed to understand the impact plastics have on other material markets.

Jan 1, 1991

By M. Maier

Geographic Information Systems (GIS) has evolved into a powerful tool for analyzing spatial and attribute data in many industries including mining. Modern field data collection techniques add another dimension to the use of data in the field and enhance the utilization of GIS for mining applications. This discussion will review how field data is collected and how office data and maps can be taken into the field to be analyzed and verified using pen-based computers and differentially corrected GPS.

Jan 1, 2001

By Parkhurst D. H

It is shown that a differential colorimetric technique can be used as a routine method for the estimation of titanium in beach sands, and their ore dressing products. The method will tolerate the presence of most of the other elements usually found in beach sands. The accuracy is shown to be within the limits of ±0ò31 per cent for concentrates containing more than 95 per cent titanium dioxide and ±1 per cent for tailings containing 0ò2 per cent titanium dioxide. The method is described for use with a Hilger "Spekker" absorptiometer.

Jan 1, 1957

By David B. Dill, Edgar R. Lea

The zinc deposits of the Balmat-Edwards Division of the St. Joseph Lead Company in northern New York State provide some 10 per cent of the domestic zinc produced annually within the United States. These complex ore deposits are contained within marbles of the Precambrian Grenville series, in a repetitive sequence of dolomites and silicated units. The Balmat ore bodies are localized at various intervals throughout some 1800 feet of the stratigraphic column on the northwest side of a band of gneiss that has continuity to the Edwards area, some 10 miles to the northeast. The Edwards ore bodies are located to the southeast of this gneiss. The marble formations are thought to have included repetitive intervals of marine sedimentation that provided mineralized source "beds" and were subsequently folded, flooded, and injected with melts at great depth and were sheared, recrystallized, and reconstituted. Detailed structural and stratigraphic studies throughout the northwestern Adirondacks, in the Balmat-Edwards district, and at each mine in particular indicate the close dependence of the ore deposits on the enveloping structure whether it be local, district-wide, or regional in scope. Primary folding has developed a northeast regional trend with northwest dips. Secondary folding has been developed by an almost horizontal northeast-southwest-oriented shear couple in the plane of the regional trend. The secondary folding has produced crossfolds that intersect the regional northeast trend and plunge north to northwest at various angles. The ore bodies are found within certain stratigraphic horizons where repeated alternation of competent and incompetent beds encouraged unusually complex folding. Analysis of individual mine structures indicates that the location of each deposit is controlled by structural crossing of primary and secondary folding. The ore bodies, which are tabular, lenticular, or pod-like in form, have features that suggest parallelism to true bedding or modified flow banding, developed by northeast-southwest shearing stresses related to the development of the crossfolds. The ore deposits in general follow both structural and recrystallization trends within the wall rocks. Mobilization of the pre-metamorphic ore minerals is believed to have involved a combination of plastic flow under stress and solution of the sphalerite, minor galena, and pyrite. The ore fluids are thought to have been guided by secondary shearing and microbrecciation into structurally prepared areas where reprecipitation took place. The presumed premetamorphic mineralization now exhibits epigenetic high-temperature features related to late-stage metamorphism.

Jan 1, 1968

By T. Burchett, F. Stanley, K. McGough, G. Luttrell

The vast majority of U.S. coal preparation plants utilize screen-bowl centrifuges to dewater their fine clean coal products. In light of this popularity, researchers at Virginia Tech have engaged in a variety of laboratory and industrial field test programs to develop technological enhancements that have the potential to further improve the performance of this important solid-liquid separation process. These enhancements, which include simple design modifications and new reagent packages, have been shown to significantly improve solids recovery and reduce product moisture in several experimental trials.

Jan 1, 2006

By L. R. Gremillion

Chemical and mineralogical data on 25 apatitic phosphate ores of diverse origins from commercial deposits around the world were widely variable. From 14 to 18 chemical constituents of each sample were determined, and each sample contained 4 to 10 mineral phases. Altogether there were 34 different mineral phases, many of which occurred in only one sample. The samples contained varieties of francolites, fluorapatites, and mixed hydroxyl-fluorapatites. The apatite compositions calculated from the chemical data showed that certain types of substitutions were characteristic of different apatite varieties, but every variety had some degree of substitution of (CO3)2 for (PO4)3 and the P2O5 contents of the apatites ranged from 35.1% for a North Carolina apatite to 41.9% for a Missouri apatite. In a concentrate with a grade of 32% P2O5, the North Carolina sample should contain about 8.7% gangue and the Missouri sample about 23.7% gangue. To optimize the digestion process of a phosphate are, it is necessary to consider the dissolution behavior of the different mineral phases during acidulation and the effects they may have on the chemical properties of a fertilizer intermediate. In the production of wet-process acids or superphosphates, the acidulation of certain minerals may cause foaming and formation of sludge, filtration, corrosion, and handling problems.

Jan 1, 1978

By Mehrotra G. M, Frohberg M. G

Based on the concepts of statistical thermodynamics of athermal mixtures, an approach is developed which is capable of quantitatively explaining the thermodynamic properties of binary silicate systems. Expressions for the ionic fractions of various anionic linear and nonlinear chain polymers are derived. The developed expressions for free energy of mixing are tested by applying these to the system PbO-SiO2. The ionic fractions of various chain polymers in this system are calculated. The two cases, namely, of linear and nonlinear chain polymers are compared with each other.Limitations of earlier models are pointed out.

Jan 1, 1975

By Donald H. McLaughlin

PRICES paid for goods and services in paper currencies are undoubtedly determined by many interrelated factors, but among them none is more specific in pushing prices toward higher and higher levels than the vast increase in debts and monetary obligations of our own and practically all major governments. There is nothing unorthodox in the situation in which the gold miners find themselves today. With wages and the prices of all materials required in the production of gold at the high levels characteristic of a period of prosperity, phony or otherwise, and with shortages of both men and machinery to contend with as well, the spread between the returns in paper dollars that must be accepted for gold in the United States and the cost of producing it is rather painfully small for most producers. Technical

Jan 1, 1948

By S. C. Termes

The Bureau of Mines has used Fourier transform infrared spectroscopy (FT-1R) to study in situ reactions of aqueous solutions of potassium ethylxanthate with CU(II)-and Pb(II)-activated sphalerite plates, in which the plates were both the infrared-transparent windows and the reacting surfaces. A copper (I) ethylxanthate formed predominantly with Cu(II)-activated sphalerite, regardless of the activation time. The products formed on Pb(II)-activated sphalerite depended on the activation times; a short activation time (30 min) yielded a lead ethylxanthate-like product, but a long activation time (90 min) yielded a considerable amount of dixanthogen.

Jan 1, 1986

By Aleksandar D. Bugarski

Despite extensive research efforts conducted in the past decades, occupational health risks associated with exposure to nano and ultrafine aerosols emitted by diesel power equipment are still not completely understood. The complexity of physical and chemical properties of diesel aerosols, constantly changing with the implementation of advanced diesel emissions control technologies, make this task rather challenging. The objective of this paper is to identify and characterize nanometer and ultrafine aerosols emitted by diesel engines in the underground environment and evaluate the effects of selected contemporary control technologies on physical properties, chemical composition, and in-vitro toxicology of diesel aerosols. The physical and chemical properties of the nanometer and ultrafine diesel aerosols are to be characterized through a test series in the NIOSH Lake Lynn Laboratory experimental mine. The crucial part of the study has been development of a facility that allows researchers to generate field results with precision and accuracy characteristics of a laboratory environment. The knowledge obtained from this study should strengthen our understanding of the health implications related to exposure to diesel particulate matter and aid in assessing the potential of various control technologies for reducing this exposure.

May 1, 2007

By V. B. Dale

This paper is one of a series covering the mineral resources of the Nation. It briefly describes most of the known tungsten deposits of New Mexico. Most of the descriptions are from field examinations by the senior author. Reported tungsten occurrences that were not visited are listed below: Colfax County: Occurrences of ferberite in thin veins in Willow Creek near Elizabethtown.4/ Dona Ana County: Small, low-grade occurrences of scheelite near the summit of the Organ Mountains about 15 miles east of Las Cruces. Hidalgo County: Scheelite reported in the Daisy mine 7 miles southeast of Hachita. Ores are carbonates containing copper, gold, silver, and bismuth.5/

Jan 1, 1959

By Chris Kelly

The Monroe County Quarry is an open pit granite quarry located near the town of Bolingbroke. Monroe County. Georgia. The quarry has been in continuous operation for approximately 10 years. The quarry covers approximately 27 acres and has an annual production rate of 1.0 million tons. On the morning of April 26. 2000 a sudden rapid highwall failure occurred at the west end of the north wall of the quarry pit. The failure occurred approximately one hour after a three inch-wide crack was observed in an access road located at the crest of the highwall. No indications of failure had been observed prior to the development of the crack. The active mining area had been at the base of the failed area. The pit was successfully evacuated prior to the failure and there were no losses of either personnel or equipment. The amount of failed material was estimated to be in excess of two million tons. In order to ensure a safe working environment at the quarry a slope monitoring program was established in the area of the failure. The program consisted of using an EDM survey instrument to periodically measure the location of survey prisms installed at carious points on the north wall. The locations of the prisms were recorded over several months and changes in location were analyzed in order to identify and characterize the movement of the failed mass. The results of the analysis provided a basis for recommendations regarding access to various areas of the quarry. This paper discusses the factors contributing to the failure, the method of post-failure slope monitoring, anti the interpretation of the monitoring data.

Jan 1, 2002

By Singh BN, Chakravarty PK, Chatterjee LM

Indian blast furnaces operate with coke gener- ally containing 24 to 28% ash compared to 10-15% ash in coke in most other parts of the world. The operating problems are further aggravated by the high alumina content and the adverse alumina to silica ratio in the ore. The above factors not only increase the coke rate but, at the same time, increase the flush slag volume, make the bosh slag highly limey and thereby viscous, and produce a flush slag containing 24 to 26% alumina. Relative- ly low flame temperatures (RAFT) make conditions more difficult. The high basicity of the bosh slag limits the maximum flush slag basicity to around 1.0, beyond which the burden movement is adversely affected by the viscosity of the bosh slag: This effect is partly controlled by operating blast furnaces with high MgO in the flush slag (around.10%), which also improves the desulphurizing power of slag. Steps are underway in some plants to inject lime through theòtuyeres to control the bosh slag basicity and also to neutralise the large quantity of silica which is released at the tuyere level from the coke ash, so that the silicon content of the hot metal can also be controlled. High bosh slag basicity coupled with the characteristics of iron ore/aggolmerates, widens the softening-melting zone and alters the shape of the softening-melting zone. This leads to operat- ing difficulties and poor hot metal quality. This paper discusses the above aspects of Indian blast furnace operation and steps being taken to surmount some of the above difficulties.

Jan 1, 1981

By Z. G. Guan

The tungsten ore in Xingluokeng belongs to a symbiotic deposit containing granite and fine vein-type wolframite and scheelite. The tungsten (WO3wolframite) accounts for only 0.233% of the raw ore, 49.60% of the , 49.60% of the scheelite and 0.8% of the tungstite. The dissemination size of the tungsten ore is extremely uneven, with 0.02~1.28 mm for scheelite and 0.01~1.28 mm for wolframite. The dissemination size of scheelite is coarser than that of wolframite. The size of 83% of scheelite and 60% of wolframite is greater than 0.04 mm. The composition of minerals in the ore is quite complex. The major metallic minerals include wolframite, scheelite and pyrite, which are followed by molybdenite, chalcopyrite, arsenopyrite, limonite, magnetite, hematite and siderite. The major gangue minerals include quartz, feldspar, muscovite, biotite and sericite, which are followed by chlorite, fluorite, apatite, dolomite, etc. According to the dissemination features and liberation degree of the tungsten minerals, the technology flowsheet of gravity concentration for coarse particles and flotation for fine particles to re-cover the low-grade and fine vein-type tungsten minerals is adopted, and -0.7 mm is selected as the processing size. The closed-circuit grinding procedure, with the combination of the rod mill and high-frequency vibration screen, is adopted. The grinding product is classified into three products of -0.7 +0.2 mm, -0.2 +0.04 mm and -0.04 mm. The gravity separation is adopted for the former two to recover tungsten minerals and the flotation is adopted for the last one. Under the condition that the raw ore contains 0.23% WO3, some technology indexes of beneficiation have been achieved. The gravity tungsten concentrate contains 63.54% WO3 with the recovery 70.11%. The slime flotation tungsten concentrate contains 35.22% WO3 with the recovery 10.48%. The composite tungsten concentrate contains 57.53% WO3 with the recovery 80.59%. Thus, the tungsten minerals are re-covered effectively.

Jan 1, 2014

By B. H. Zhao

A low grade Pt-Pd ores, with 1g/t Pt and 0.13g/t Pd, and 8.70% Fe and 2.50% P2O5 is experimented to recover of Pt and Pd. The flowsheet is proposed which consists of Pt-Pd selective flotation, apatite flotation from tailings of Pt-Pd flotation, magnetic separation of magnetite from apatite flotation tailing. With butyl xanthate, N-ally group-O-isobuturyl-thioanimoformate and Sodium y-89 xanthate as collectors, sodium silicate as depressant, and sodium carbonate as pH regulator, a concentrate, assaying 324.52 g/t Pt and 45.62 g/t Pd, is obtained with recoveries of 87.23% Pt and 76.89% Pd from surface ore. A concentrate, assaying 1693.53 g/t Pt and 64.12 g/t Pd, is obtained with recoveries of 88.54% Pt and 83.78% Pd from primary ore. At same time, A iron concentrate assaying 64.12% Fe with a recovery of 24.94%, and a apatite concentrate assying 30.32% P2O5 with a recovery of 80.12% are obtained.

Jan 1, 2014

By Edmund S. Leaver

The selection of a process for treating a gold ore is governed primarily by the characteristics of the ore under consideration. The form in which the gold occurs, its mode of association with other minerals, and the size and surface condition of the gold particles are important factors which influence materially the choice of procedure for recovering gold. A knowledge of these characteristics may be obtained by microscopic and chemical methods combined with experimental testing. Cyanidation and amalgamation, either alone or in conjunction with flotation and gravity methods, are peculiarly adapted to the treatment of gold ores, especially those of relatively low grade. Gold alloys readily with mercury provided both present clean surfaces. The presence of oils and grease, antimony and arsenic minerals, or soluble sulphides have a harmful effect. Very small, flaky particles of gold frequently are lost in amalgamation because of noncontact with the mercury. Fine gold in pyrite, or gold having rusty or contaminated surfaces, is often lost for the same reason. Grinding or some form of abrasion sometimes removes surface films of iron oxide or substances of a similar nature, and alkalies or other chemicals are used to remove grease. Gold is readily soluble in cyanide solution, and this method of treatment is particularly effective in the recovery of gold from the tailings resulting from other types of concen¬tration procedure. Cyanide solutions must contact the gold to insure recovery, and the porosity of the ore treated and the fineness of grinding required are important governing factors. The use of lime in cyanidation is necessary to protect the cyanide, to precipitate undesirable substances, and to settle slimes. Certain substances in ores are harmful in cyanidation; chief among them are those that combine with cyanide, forming cyanides, and carbon which precipitates gold from solution. Arsenic and antimony are also harmful if present in sufficient quantity. These and other difficulties encountered in cyaniding certain ores often are overcome by roasting prior to leaching. Zinc dust is used almost universally for precipitating precious metals from cyanide solutions. The refining and melting of the product may be accomplished by oxidizing the zinc before melting it in graphite pots with fluxes, although sulphuric acid is now used largely to remove the zinc before melting. Straight cyanidaticn practice is being replaced by flotation as a major process, followed by cyanide leaching of the tailings, but amalgamation is still needed as a primary process for the recovery of coarse gold before either flotation or cyanidation.

Jan 1, 1935

By Edmund S. Leaver

The selection of a process for treating a gold ore is governed primarily by the characteristics of the ore under consideration. The form in which the gold occurs, its mode of association with other minerals, and the size and surface condition of the gold particles are important factors which influence materially the choice of procedure for recovering gold. A knowledge of these characteristics may be obtained by microscopic and chemical methods combined with experimental testing. Cyanidation and amalgamation, either alone or in conjunction with flotation and gravity methods, are peculiarly adapted to the treatment of gold ores, especially those of relatively low grade. Gold alloys readily with mercury provided both present clean surfaces. The presence of oils and grease, antimony and arsenic minerals, or soluble sulphides have a harmful effect. Very small, flaky particles of gold frequently are lost in amalgamation because of noncontact with the mercury. Fine gold in pyrite, or gold having rusty or contaminated surfaces, is often lost for the same reason. Grinding or some form of abrasion sometimes removes surface films of iron oxide or substances of a similar nature, and alkalies or other chemicals are used to remove grease. Gold is readily soluble in cyanide solution, and this method of treatment is particularly effective in the recovery of gold from the tailings resulting from other types of concentration procedure. Cyanide solutions must contact the gold to insure recovery, and the porosity of the ore treated and the fineness of grinding required are important governing factors. The use of lime in cyanidation is necessary to protect the cyanide, to precipitate undesirable substances, and to settle slimes. Certain substances in ores are harmful in cyanidation; chief among them are those that combine with cyanide, forming cyanides, and carbon which precipitates gold from solution. Arsenic and antimony are also harmful if present in sufficient quantity. These and other difficulties encountered in cyaniding certain ores often are overcome by roasting prior to leaching. Zinc dust is used almost universally for precipitating precious metals from cyanide solutions. The refining and melting of the product may be accomplished by oxidizing the zinc before melting it in graphite pots with fluxes, although sulphuric acid is now used largely to remove the zinc before melting. Straight cyanidation practice is being replaced by flotation as a major process, followed by cyanide leaching of the tailings, but amalgamation is still needed as a primary process for the recovery of coarse gold before either flotation or cyanidation.

Jan 1, 1935

By Paul J. Guay

This report presents the results of evaluating a longwall mining system specifically designed to extract a very deep web (60 inches or deeper) from a longwall panel. The report includes a productivity and cost analysis comparing the new mining sys-tem with a high capacity conventional longwall operation taking a 30-inch wide web. The analysis shows the new system will increase annual production 44 percent and decrease cost per ton off the face 21 percent. The report also includes conceptual drawings and specifications for a high capacity four-drum shearer and a unique shield type of roof support specifically designed for very wide web operation. The advantages and problems associated with wide web mining are discussed in general and as they relate specifically to the equipment selected for the new mining system. The study concludes by recommending that surface coal loading tests be conducted as the follow-on work.

Jan 1, 1978

By Mario Samamé Boggio

El presente texto señala la historia de la minería en el Perú a través de dos períodos: Pre-historia e Historia. La Pre-Historia comprende dos épocas: Pre Inca e Inca.

Jul 1, 1983

Data released by the Commerce Department's Bureau of Economic Analysis show continued gradual change in the real GNP's rate of growth in 1984, which has eased from an annual growth rate of 10.1 percent in the first quarter lo 7.1 percent in the second quarter, and then to 2.7 percent in the third quarter. The automobile industry strike in the last half of September had only a small effect, estimated at less than a 0.1 percentage point reduction in the growth rate. Among the components that comprise the GNP, personal consumption and fixed investment grew at lower real rates in the third quarter than in the second quarter, while net exports decreased. Personal consumption expenditures increased $0.4 billion in the third quarter, compared with an increase of $20.1 billion in the second quarter. Nonresidential fixed investment increased $3.9 billion in the third quarter, compared with $9.6 billion in the second quarter. The other component of fixed investment--residential investment--increased from $60.8 billion in the second quarter to $61.2 billion in the third quarter. Real net exports of goods and services decreased $1 1.3 billion in the third quarter, compared with a $3.1 billion decrease in the second quarter. Although exports increased from an annual rate of $144.7 billion to $150.2 billion, imports increased much more, from an annual rate of $1 56.2. billion to $172.8 billion (table 1).

Jan 1, 1984