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General economic conditions continued to improve in the second quarter of 1984 as real gross national product advanced at an annual rate of 7.5 percent (table 1). This followed an even larger first quarter annual rate increase of 10.1 percent. The slower second quarter growth was greeted as a sign that the economy is not over-heating. The signs of slowed growth in some sectors suggest that the recovery may continue well into 1985 without the inflation symptomatic of a rapid recovery. Most of the slowdown in growth was absorbed by business inventories, personal consumption of durable goods, and residential fixed investment. Business inventories grew by only 68 percent as much as in the first quarter, personal consumption for durable goods grew by 58 percent of the first quarter rate, and residential fixed investment slowed to only 44 percent of the first quarter growth. Sectors with accelerated growth in the second quarter included personal consumption of nondurable goods and of services, which increased at annual rates of 9.6 percent and 3.8 percent, respectively, and Federal purchases of goods and services, which increased at an annual rate of 47.9 percent.

Jan 1, 1984

By J. Drimmer

The past several decades have seen the rapid expansion of multinational mining companies? exploration and production activities around the globe. This trend has resulted from a number of factors, including increased demand for resources as a result of worldwide economic growth, the diminishment of known and proven reserves, rising commodity prices, technology improvements, and the liberalization of investment regimes in developing countries with significant natural resources. With those opportunities, however, come associated risks and significantly increased legal compliance obligations that may be imposed by various bodies. That includes domestic regulations, as well as foreign civil and criminal laws with extraterritorial reach. A failure to adhere to those laws can have dire consequences, including substantial monetary fines and penalties, severe damage to a company?s reputation, and even jail time for individual company employees.

Jan 1, 2010

By Masami Nakamoto

Controlled thermolysis of gold(I) thiolate complex, [C14H29(CH3)3N][Au(SC12H25)2], at 180 °C for 5 h under an N2 atmosphere produces novel gold nanoparticles passivated by alkyl groups derived from the precursor complex, the TEM photograph of which shows spherical particles with average diameter 26 nm. Since Brust et al. reported the two-phase reduction of AuCl4 - by NaBH4 to afford monodispersed gold nanoparticles passivated by alkanethiolate ligands (1), plenty of preparative investigations on gold nanoparticles (2,3) and its surface modification (3,4) have appeared, because of their potential applications in microelectronics (5). However, those preparative methods generally involve the reduction of AuCl4 - by reducing agent NaBH4 in the presence of suitable organic stabilizers such as alkanethiol (1-4), phosphane (5), quarternary ammonium salts (6), surfactants (7) or polymers (8). On the other hand, O?Brien et al. recently reported the preparation of organically capped gold nanoparticles at 190 °C, where tri-n-octylphosphine oxide and/or n-octadecylamine are used both as a reaction medium and as a passivating ligand (6), but this procedure also needs NaBH4 as reducing agent. Our strategy of novel preparative method of gold nanoparticles is the combination of reductive elimination of thiolate ligands and simultaneous attachment of organic moiety on the growing nuclei. Gold(I) thiolate complexes with ammonium cations were useful for our preparative method. We now report the controlled thermolysis of gold(I) thiolate complexes, [R(CH3)3N][Au(SC12H25)2] and [R(CH3)3N][Au(SC6H4-p-R?)2] (R= C14H29, C12H25; R?= C8H17, CH3), under an N2 atmosphere, where the powder of gold(I) thiolate complexes completely melts to afford the precursor liquid and then the liquid gradually decomposes. In spite of no use of reducing agent and solvent, reduction reaction is thermochemically induced to afford novel gold nanoparticles passivated by alkyl groups rather than by alkanethiolate ligands. Figure 1a shows a typical transmission electron microscopy (TEM) image of gold nanoparticles prepared by thermolysis of [C14H29(CH3)3N][Au(SC12H25)2] at 180 °C for 5 h, indicating a controlled growth of spherical gold nanoparticles. As shown in Fig. 1b, these spherical gold nanoparticles display the size distribution ranging from 5 to 50 nm. Although the particle size is larger than that of thiol-derivatized gold nanoparticles (less than 5 nm) prepared by NaBH4 reduction (1-3), the aggregation of gold nuclei is smoothly regulated and the growth of core gold is limited to be 26 nm in average diameter in spite of thermal procedure.

Oct 1, 2003

By K. H. J. Clarke

"ALTHOUGH nickel was not identified as a separate element until a Swedish scientist, Axel Frederick Cronstedt, did so in 17 51, its utilization dates from pre-historic times. From its humble beginnings nickel has grown in importance until, today, in our clocks, television sets, automobiles, and air-planes, in our bridges, tableware, farm implements, and the equipment which processes our food, it is constantly at our service.For convenience in assembly, data and information relative to The Marketing of Nickel will be outlined in five phases: (A) Sources, (B) Distribution, (C) Utilization, (D) Market Development, and (E) Conclusions."

Jan 1, 1960

By Edward Thomas

Yucca Mountain Overview The U.S. Department of Energy?s Yucca Mountain Project is a geologic repository project designed to receive, handle, package, transport, and emplace spent nuclear fuel and high level radioactive waste. The planned repository would be located in Yucca Mountain on the western edge of the Nevada Test Site, about 90 miles northwest of Las Vegas, Nevada, and would include both surface and subsurface areas. Yucca Mountain rock formations consist of successive layers of volcanic rocks (called tuffs) approximately 14 to 11.5 million years old, formed by eruptions of volcanic calderas to the north. With the volcanic rock the potential for methane emission is not an issue and the subsurface repository is a non-gassy (methane) classification. This paper will provide a summary of the development ventilation system design that provides fresh air for subsurface construction activities, and the emplacement ventilation system design that removes heat generated by the waste packages. The subsurface layout, illustrated in Figure 1, contains 108 emplacement drifts, one Performance Confirmation(PC) observation drift, nine intake/exhaust shafts, and three access ramps. The existing Yucca Mountain facilities, shown in bold lines in Figure 1, include a 7.8 km long, 7.62 m (25 ft) diameter U shaped tunnel that is formed by the North and South Ramps at both ends of the Exploratory Studies Facility (ESF) drift and a 1.5 km long, 5.0 m (16.4 ft) diameter Enhanced Characterization of the Repository Block drift (ECRB) that were constructed from 1994 through 1998. These drifts were used for site characterization activities and have been incorporated into the subsurface repository configuration. The unexcavated perimeter access main and exhaust main drifts are typically 7.62 m (25 ft) diameter TBM excavations and the emplacement drifts are 5.5 m (18 ft) diameter TBM excavations. The turnouts leading into the emplacement drifts are to be excavated by either mechanical, or drill and blast methods and serve as the launch chambers for the emplacement drift TBM excavations.

Despite modest improvements in the performance of domestic interest rates and gross national product,1 fixed investment in domestic producers' durable equipment continued to weaken during the second quarter of 1982 and declined at a 12.8 percent annual rate compared with the first quarter.2 Large declines occurred during the second quarter in expenditures on many of the major mineral-consuming industries such as aircraft, computers, agricultural and construction machinery and mining and oil field equipment. These data appear to be consistent with the low level of business investment plans for 1982 reported in the DOC's Bureau of Economic Analysis survey of expenditures on new plant and equipment.3 Domestic and foreign industrial production and mineral industry production activities continued to decline in the most recent period because of weak demand conditions (Tables 1 and 2). The U.S. mining production index declined 7.7 percent between April and June as compared with 1.2 percent for total U.S. industrial production (Table 1).

Jan 1, 1982

By Johnson I. R, Muir M. D

The Dugald River zinc-lead deposit is located 60 km northwest of Cloncurry. It was discovered prior to 1881, and since 1937, has been the subject of several drilling programmcs which have outlined a resource potential of 60 million tonnes grading 10 per cent zinc, 1 per cent lead, and 30 g/t silver.The deposit is a classical example of stratiform zinc lead mineralization in a black shale host. It occurs within a restricted clastic sedimentary basin within the Corella Formation of Carpentarian (Middle Proterozoic) age. Sabkha, lacustrine and fluvial sedimentary environments have been recognized within this basin. Each environment is characterized by suites of evaporite mineral pseudomorphs, after both shortite and gypsum, indicating that both alkaline and hypersaline environments prevailed at different times during basin evolution. The Dugald Slates which host the zinc-·lead mineralization are lacustrine in origin. Thin Mount Isa-type K-rich tuffite beds occur in the Dugald Slates and in the sabkha sequences.The basin as a whole appears not 10 have been marine, and 10 have had strong tectonic controls on its depositional history.The mineral deposit itself is conformable within the Dugald Slates and many primary sedimentary and soft-sediment deformation structures are preserved. It has a strike length of 2 km, average width of 10 m, and a westerly dip of 50-80 . Drilling suggests continuity to 1000 m vertical depth. The predominant sulphides are pyrrhotite, pyrite, sphalerite and galena in graphitic slate and quartz-carbonate ganguc. Anomalous concentrations of barium, manganese, cadmium, mercury and antimony are present in the ore.The deposit crops out over a distance of 2 km as a gossan ranging from 5-15 m in width. There is a striking vegetation anomaly over the gossanous outcrops. The gossan is enriched in lead, silver, antimony, barium, titaniulll, silica and iron, with respect to the primary mineralization. The depth of total oxidation reaches about 20 m.Cieochemical and geophysical test surveys over the deposit give pronounced anomalies.

Jan 1, 1982

By D G. Randall, R Jivanji, J Nathoo, T Reddy

Paradoxically, the increased emphasis on water treatment in mining has generated a new problem û hypersaline brines. Currently brines are either disposed of into ash systems, lined evaporation ponds or hazardous waste sites. Evaporative crystallisation (EC) is an alternative, but the energy requirements can be prohibitive and the salt product is still a waste that must be disposed of. Eutectic freeze crystallisation (EFC) is an alternative technology that is capable of separating aqueous solutions into pure water (as ice) and pure, solidified solutes. It is highly energy efficient and does not depend on the introduction of any solvents. In addition, the simultaneous production of pure ice and potentially saleable pure salt(s) is a major advantage. Although EFC has been shown to be effective in separating a single salt and water, it is still in the early stages of being applied to the multi-component hypersaline brines that are typical of reverse osmosis retentates generated by mining and extractive metallurgy.This paper presents an EFC brine treatment protocol developed by the Crystallisation and Precipitation Unit at the University of Cape Town. The protocol incorporates brine analysis, thermodynamic modelling to establish which salts will freeze out and at which temperatures, followed by experimental studies to determine the kinetic parameters, such as nucleation temperatures, salt yields and crystal purity.Case studies showing the application of EFC for the purification of typical brines containing high levels of sodium, chlorine, sulfate and ammonia (Brine 1) and a mixture of sodium and magnesium sulfate (Brine 2) are covered. Modelling tools were applied to describe the phase behaviour of the multi-component saline systems under different process conditions. Experimental validation was carried out using synthetic brines of different (and increasingly complex) compositions. The results showed that EFC could be used to selectively recover the sodium as a sodium sulfate salt from both different brines. The simulation tools were useful in the analysis and understanding of the process.A preliminary economic analysis showed that the operating costs for EC were approximately nine times those for EFC, but the capital costs were much less- equipment for EC cost about half that of EFC. However, it is important to note that the capital cost calculations for EC are based on a technology that is already well established and with only relatively marginal future equipment cost savings expected. In contrast, EFC is a new technology, with significant future technology improvements expected.

Jan 1, 2009

By M. Carrales

This Bureau of Mines report presents information on the sulfur content of crude oil in the United States and in some foreign countries. Data are presented for oil produced in 1971 from fields in 26 States that accounted for about 76 percent of total U.S. oil production; the foreign data cover fields in 24 foreign countries that accounted for about 64 percent of the total oil produced from these countries in 1971. Most of the data are presented in tabular form.

Jan 1, 1975

By Sotiris N. Kamenopoulos, Zach Agioutantis

Rare earth elements (REEs) are considered critical minerals for industrial and defense sectors. REEs are not as rare as the word “rare” portrays; yet, the exploitable and/or profitable deposits of REEs may be found only in certain geographical areas. The political and social conditions characterizing these areas may not always be in favor of mining operations. These conditions are imposing the need for extra consideration on the geopolitical constraints prior to any decision-making and before any mining project begins. This study assesses the risk related to mining projects for areas that feature REE deposits based on a geopolitical viewpoint. Probable ranking differences between the current assessment and a 2015 assessment are discussed. The comparative indicators used and the appraisal procedure applied in this comparison are based on a number of different geopolitical indicators. Several ranking changes occurred between 2015 and 2019.

THE Yallourn chimney has aroused interest, as it is, for the time being, the tallest structural erection in Australia. Its height was not decided on, however, with the object of breaking records, but is purely incidental to the purpose which it serves. Theboiler plant at the briquetting works (first instalment) consists of five Babcock and Wilcox land-type water-tube boilers, each of 4510 sq ft. heating su:r£ace and 225 sq. ft. grate area in the form of step grates. Four boilers will normally produce 73,000 lb. of steam per hour at a gauge pressure of 265 lb. and a temperature of 6500 F., the fifth boiler being a reserve. Each boiler will consume about 100 tons of Yallourn coal per 24 hours. Provision is made for future installation of economizers, should it be found desirable. Designing for this condition, and allowing for a waste gas temperature of 3500 F. and an air temperature exceeding 1000 it was found necessary to have a draft of about 1.3 in. (water gauge) at the base of the chimney, and to deal with about 2000 cub. ft. of gases per second. Estimates were made of the cost of providing the necessary draught by means of fans and by means of a tall chill).ney. The annual charges of the two methods differed only slightly, and the tall chimney wasselected as being the more general practice in briquetting factories.Estimates were prepared for brick and concrete chiIlllleys. Yallourn bricks at that time were hand-made, and, while very suitable for domestic work, were not capable of withstanding high compressive stresses. The chimney design to suit these bricks thus required to be on very ample lines, resulting in high cost. Machine-made bricks from Melbourne would cost about £5 10s. per thousand on the site, with extra for radials, so that high cost again resulted. On the score...

Jan 1, 1924

Factors leading to the necessity for some individual testwork in solving most specific hydraulic transportation problems are listed and a description is given of a method used in determining critical flow conditions. An outline is given of the basic theory of the purpose of the testwork, and a means of applying test results for varied pipeline diamet.er and material conditions follows. Engineering and economic factors are applied to the solution of a specific hydraulic transportation problem and the use of the test results in plant practice is illustrated. The advantages of connecting pumps in series in centralised pumping stations rather than individually along the pipeline are stressed. Some notes are added on the future possibilities and economies of post pump injection of solids into high pressure pipelines.THE HYDRAULIC TRANSPORTATION OF SANDSAs well as all the classical variables involved in a pipeline installation, one must consider, when solids are to be transported, the effects of such variables as:(i) Proportion of solids in the pulp.(ii) The average specific gravity of the pulp.(iii) Specific gravity of the solid material.(iv) Solid particle average sizing and possibly shape.(v) Solids particle grading.(vi) Pipeline diameter for effects other than classically hydraulic.(vii) Pipeline material.(viii) Fluid viscosity.(ix) Pump characteristics.(x) Abrasive or corrosive properties of the pulp.Not surprisingly, the application of published data to the hydraulic transportation of a specific material is difficult if not well nigh impossible. Most hydraulic transportation investigations also involve economic and site factors vary...

Jan 1, 1959

By Shelby Z. Palya

"INTRODUCTION The Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mining substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable. This issue describes reports and articles published during the period January 1, 1975, to December 31, 1979. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960; 2 the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960; 3 the 5-year lists of publicatioll3 and articles, from January 1, 1960, to December 31, 1964,4 from January 1, 1965, to December 31, 1969,5 and from January 1, 1970, to December 31, 1974; 6 and the annual lists of Bureau publications and articles from January 1 to December 31, 1975,7 from January 1 to December 31, 1976,8 from January 1 to December 31, 1977,9 and from January 1 to December 31, 1978.10"

Jan 1, 1980

By William W. Adams

A new record in accident prevention was made by the metal-mining a industry of the United States in 1938, as signalized by a lower fatality rate than in any previous year. The rate was less than half as high as in 1911, the earliest year for which figures are available. A good safety record was also established in the prevention of nonfatal injuries, as the injury rate was lower than in any other years except 1931 to 1935, a 5-year period notable for its unusually low injury rates. Employment was more limited in 1938 than in 1937, both in number of men employed and total number of man-hours worked. The number of workdays per man also was smaller than in 1937. Operating companies reported that 7,233 mines were active in 1938 or some part of the year and that the total number of men employed was 103,027. This figure represents the summation of the average number of men employed as reported by the companies, the average for each mine being that for the period during which the mine was active. The number of employees at all mines in 1938 was 15,402 less than in 1937. Reports covering all mines indicated a total of 188 million man-hours worked during the year, or 21 percent less than the nearly 240 million man-hours worked in 1937. In the performance of this work accidents occurred that resulted in the death of 156 employees and the injury of 1.2,722, each injured employee being disabled for more than the remainder of the clay on which he was hurt.. The fatality rate for 1938 was 0.83 per million man-hours worked, which was 9 percent more favorable than the rate of 0.91 for 1937. Nonfatal injuries occurred at the rate of 67.61 per million man-hours worked, an improvement of 10 percent compared with the injury rate of 75.37 for 1937.

Jan 1, 1941

By A. C. Wilson

In 1991, local prospector C. ?Mickey? Clement recovered at least three alluvial diamonds from the Michipicoten River. Two of these stones were sent to the Department of Mineralogy, Royal Ontario Museum, where they were identified as industrial grade diamonds with weights of 1.05 and 1.13 carats. Both stones were described as frosted and graphite-inclusion riddled. In 1995, prospector Sandor Surmacz and geologist Marcelle Hauseux discovered diamonds in bedrock approximately 20 km north of the Michipicoten River. An 18.1-kg bulk sample of a xenolith-rich lamprophyre, taken from an outcrop at the side of the Trans Canada Highway north of Wawa, yielded 1 macro diamond and 5 micro diamonds. All but one was gem quality (Sage 2000). Since then, more than 36 occurrences of diamonds in bedrock have been reported in an approximately 30 km2 area centred 20 km north of the town of Wawa. The occurrences are hosted within a sequence of unusual, Archean-aged, heterolithic breccias previously considered to have no economic significance. Ten kimberlite occurrences also have been confirmed in the Michipicoten greenstone belt in the last 5 years. Two of these kimberlites are diamondiferous. To date, expenditures on property acquisition and diamond exploration in the Wawa are estimated at $120 million (CAN). This paper summarizes the geological observations made on these occurrences and discusses including the relationship between the occurrences and the regional geology.

May 1, 2003

By Mathew Janes

"Sheet piles remain an economic solution to many shoring problems. However, installation of sheet piling suffers high noise and vibration with conventional impact or vibratory methods or low production and high expense with push techniques. Many projects simply will not allow sheet piling due to vibration concerns.Installing sheet piles with a tunable, high frequency Resonant vibrator provides high production with imperceptible ground vibrations. Recent projects in Canada have proven the technique on production projects where vibration sensitive structures are present immediately adjacent to the sheet piling. A project in Whitehorse, Yukon required a Waterloo style impervious sheet pile barrier be driven immediately adjacent to a sensitive, large diameter sewer line. The 1800 m2 Waterloo barrier was driven to prevent hydrocarbon leachate from entering the Yukon River. Proposed driving of the sheet raised concerned as the sewer serviced downtown Whitehorse. Monitoring of the sewer during Resonant driving proved the ground vibrations to be imperceptible. Use of the Resonant Driver prevented all concern over ground borne vibration of the sewer and allowed the contractor to progress at conventional, high production while maintaining low cost to the owner.Subsequent projects continue to prove that Resonant driving of sheet piles achieves high production while eliminating ground vibration.IntroductionA complex environmental clean-up problem required a unique solution. A historic oil and fuel transfer station in Whitehorse, Yukon is located on the Yukon River. The facility has been in use since the Second World War and witnessed much careless activity. The sand and gravel site provided ease of transmission of hydrocarbon leachates directly into the Yukon River. Continued use of the site required a barrier wall be constructed to prevent hydrocarbon from leaching into the Yukon River. A short construction season and restrictive fisheries window made for a compressed schedule. Along the shoreline of the property and within the required clean up zone a large diameter sanitary sewer collector line was present that serviced the majority of downtown Whitehorse. The design called for a barrier wall to be constructed along the waterfront adjacent to the sewer with cofferdams constructed out into the Yukon River to recover contaminated riverbed soils. The coarse sands and gravels meant high hydraulic conductivity into any kind of excavation, including slurried or drilled shafts that may have been used to construct a low vibration shoring system. Conventional hammer or vibrator technology would result in high ground vibrations that risked damaging the sewer. The Resonant Driver method was selected for its ability to drive sheet piles with high production and zero ground borne vibrations."

Jan 1, 2014

The sulphide ores of the principal lodes of the Boulder Mines are mainly composed of a schistose guess with a varying proportion of silica and lime, containing tellurides of gold, silver and mercury, associated with iron pyrites. It is a great difficultyto obtain pure and homogeneous samples of the tellurides for analysis, and from a number of tests made with excellent specimens it was found hardly possible to procure two to agree in analysis, the precious metals being found to be combinedwith tellurium in most varying proportions indeed, a close inspection of a partially crushed specimen will reveal, even to the naked eye, the various shades of colour characteristic...

Jan 1, 1901

By L. A. Conley

This report, covering the period January through December 1976, contains abstracts of articles related to cost engineering and economics for chemical and petroleum plants, mining, and other mineral industries from the following periodicals: 1. Air Pollution Control Association Journal 2. Chemical Engineering 3. Chemical Engineering Journal 4. Chemtech 5. Coal Age 6. Coal Mining and Processing 7. Combustion 8. Drilling-DCW 9. Electrical World 10. Engineering and Mining Journal

Jan 1, 1977

The HB 2500 hydraulic breaker attachment from Atlas Copco Construction Tools features Krupp percussion technology and a service weight of 2,500 kg (5,512 lbs). This makes it ideal for demolition, tunneling, trenching, foundation work, rock mining and secondary breaking. Suitable for carriers in the 29-to 43-t (32-to 47-st) weight class, the HB 2500 accepts maximum hydraulic flow of 219 L/min (58 gpm) at 18 MPa (2,610 psi) of pressure, and delivers an impact rate of up to 550 blows per minute. The HB 2500 features PowerAdapt, a new system that automatically shuts down the breaker in the event that it receives excessive oil pressure from the carrier.

Jan 1, 2006

By E. W. Thorton

"This paper is intended to show that grinding media can effect flotation results, and in some instances the results are vastly different. I do not suggest that autogenous grinding is beneficial in the separation of all complex base metal ores, in fact I know of a case where autogenous grinding would be disastrous to any selective flotation. I do however contend that prospective flow sheets and reagent balances of any complex base metal ores should be tried with both types of grinding. I feel fortunate that the paper to be presented later in this meeting by Rene Klymouski will, I think, compliment and perhaps explain some of the results of my research.This paper will be in four parts. The first part deals with a literature survey on the subject. Surprisingly enough, very little information has been printed on the subject. The second part deals with results obtained in bench scale tests on an ore from Chester Mines Limited. It was in these tests that we realized that steel grinding was giving us serious problems. So bench scale tests are shown giving results with a stainless steel grind, a mild steel grind and a grind in a ceramic mill with ceramic billets.The third part of the paper deals with results obtained in the Mines Branch Pilot Plant, when again we ground the ore with three different types of grinding media. Incidentally, this has been the only pilot plant test made at the Mines Branch in which flotation products were made on both steel grinding and autogenous grinding on the same ore. The fourth part deals with two other New Brunswick ores and is intended to show that changing the grinding media effects ores other than that of Chester Mines Limited."

Jan 1, 1973