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By B. E. Eakin, A. L. Lee, M. H. Gonzalez

Expeximental viscosity and density data of lour natural gases are presented for temperatures from WO to 340F and pressures from 100 to 8.000 psia. A correlation is also discussed and results reported. INTRODUCTION This investigation is one of several efforts by the authors to provide viscosity data for pure hydrocarbons and mixtures. Results of some pure hydrocarbons and their mix tures have been presented." Several predictive methods and correlations have also been reported.'," This paper presents the experimental viscosity and density data of four natural gases and confirms a correlation in a previous study. APPARATUS The viscometer was described previously. 2,6 A bank of stainless steel pycnometers was included to determine density in conjunction with the viscosity measurements (Fig. I). DATA AND MATERIALS The natural gases were furnished by the Atlantic Richfield Co. (Samples 1 and 21, the Continental Oil Co. (Sample 3) and the Pan American Petroleum Corp. (Sample 4). Table 1 shows the composition of these gases obtained by mass spectrometer analysis. The pure component viscosity data used in the correlation have been published."".'"', '" Experimental and calculated viscosity data for the natural gases are presented in Tables 2 through 5. CORRELATION Starling and Ellington"' have reported several semi-empirical expressions based to a certain extent on the theory of viscosity advanced by Born and Green.' The final expression presented by Starling and Ellingto'n is: i'. (micropoise) -- /t,, exp rX(7') p ..... (I) Eq. 1 was modified by Lee et 01." to represent mixture and pure component data simultaneously. This equation has the form: F = K exp [XpY] :.........(2) where K=- (7.77 i 0.0063M)Ti 122.4 + 12.9M +T .................(3) ' ' ' X= 2.57 + ---1914.5+ 0.0095M .... (4) Y = 1.11 -r 0.04 X ........(5) Over the pressure and temperature range studied in this investigation, this equation represents the data on methane, ethane, propane, n-butane and four methane-n-butane mixtures with a standard deviation* of ? 1.89 per cent. Density data by Sage and Lacey" were used to fit the equations. Eq. 2 gives reliable values of the viscosity of light hydrocarbons without prior knowledge of experimental viscosity values, but accurate density data must be available. Eq. 2 was used to predict viscosity values for the natural gases studied in this paper. The particular set of parameters contained in Eqs. 3 through 5 gave values that reproduced experimental data within 25 per cent. Needless to say, in using Eq. 2 better density values will give better viscosity results. However, those engineers who do not have accurate density values at hand or the time, or such facilities as a library, computer, etc. readily available, may feel uneasy in using Eq. 2. Therefore, the authors sought the easiest but by no means best density prediction method, which was reported by Kaf 30 years ago. A set of density values, which were calculated based on Kay's method, and a generalized compressibility factor chart were used to fit Eq. 2. The results are:

Jan 1, 1967

By H. J. Sloman

Mining laws of the several coal-producing Stat e with respect to safety catches on mine cages and their testing are extremely variable and generally indefinite in scope. The most specific requirements are contained in the Coal Mining Laws of Washington,3/ as follows:

Jan 1, 1944

By William C. Cooley

A technical and economic study was made of the feasibility of establishing an underground hydraulic coal mine in the Wilkeson-Carbonado coal field approximately 25 miles southeast of Tacoma, Washington. The deposit contains reserves of more than 200 million tons of generally high quality metallurgical coal. It is located in nine seams of minable thickness in a complex, folded and tectonically disturbed set of anticlines and synclines. Typical dip angles are up to 60°, with minable seam thicknesses of 6 to 17 feet. A mine plan was made for a 2 million TPY mine (clean) using two shafts to access the deposit to a depth of 2500 ft. The mining method uses monitor jets to break coal by sublevel retreat mining, fluming to a sump and pumping the minus 0.25 inch coal to the surface and to a preparation plant. The plus 0.25 inch coal is hoisted by skip. Cleaned met coal would be shipped by rail for export. A middlings product would be sold as thermal coal. Assuming a coal price of $48 per short ton (FOB the mine) for the met coal and $35 for the middlings, the return on investment is estimated at 20% after taxes. The many uncertainties about the geological conditions and the specific mine design parameters make the economic analysis and conclusions somewhat tentative. A second mine could also be developed in the eastern section of the reserves to produce 1 million TPY of clean coal and is expected to have similar economics. Recommendations are made for a Test Mine and a Pilot Mine leading to a production mine.

Jan 1, 1983

By Ernesto Zelaya P

En el Perú, muchas de las empresas mineras se desarrollaron por la configuración de sus yacimientos explotados. Sin embargo, también se generaron limitaciones y restricciones en el transporte, extracción de mineral y/o desmonte dentro de las operaciones mineras. En este sentido, el presente texto señala una forma de inversión a través de un sistema de izaje, donde se realice un costo menos y una mayor productividad en la Unidad Minera Animón – EACH S. A. C. (Pique Jacob Timmers) y en la Unidad Minera Andaychagua – U. P. Yauli (Pique Roberto Letts) que son partes integrantes de las operaciones mineras de Volcan Compañía Minera S. A. A

Sep 12, 2011

A massive cobalt-containing pyrite orebody occurs in banded albite-quartz-biotite rocks at Thackaringa, some 30 km SW of Broken Hill. Because of the world-wide shortage of cobalt during the late 1970s, serious consideration was given to the development of a suitable flow-sheet to recover the cobalt from this ore. Details of a pressure leaching process in which more than 90 per cent of the cobalt is extracted from a pyrite concentrate are presented.

Jan 1, 1983

By J. R. Thoenen

In the summer of 1937 the authors began a series of time studies of the various processes employed in' the production of crashed stone. These studies, made at quarries situated in the eastern and southeastern parts of the United States, have not been completed, but to make results available to the industry as early as possible, it was decided to publish summarizes of the studies made to January 1, 1939, as a series of progress reports. The first of these dealt with power-shovel loading and was issued as Report of Investigations 3461 in September 1939. The second, issued in September 1939 as Report of Investigations 3467, dealt with quarry haulage. The present report discusses analyses of time studies of primary drilling a t the same group of quarries. OBJECT OF STUDY Pressure of business problems frequently requires the entire attention of quarry management, and in consequence internal plant economies often are neglected. Also, operating officials absorbed in their local problems are prone to overlook possible economies that would attract attention immediately were they critically examining another plant. The authors felt that technical studies at a number of plants, made by impartial engineers, might disclose opportunities to reduce costs or improve efficiency in internal plant processes.

Jan 1, 1940

By Sanjiv Dhanjal

"Often mineralogy dictates the physical properties of a material rather than chemistry. This in turn affects how that material behaves in a process plant, and whether optimum conditions for refining one mineral are different to those for refining another. For example how does refining copper from chalcopyrite differ to refining copper from bornite?Minerals are naturally occurring inorganic solids that have a definite chemical composition and an ordered atomic (crystalline) structure. X-ray diffraction is a common and highly developed method to identify and quantify minerals. X-rays are fired onto a material and the mineral is identified by the angles where the diffracted X-rays are in phase.Most X-ray analyzers are laboratory based. A sample is prepared and analyzed by a detector that travels in an arc to collect the diffraction pattern. COSMA has a curved detector which picks up the complete x-ray pattern instantaneously. Therefore, material is collected and transported through the machine where is it is analyzed continuously.COSMA measures about 0.5 tons of material per day, while laboratory analyzers measure a few grams at a time. Real time data trends are produced allowing for improved process evaluation and automatic control. The COSMA on-line system has taken X-ray diffraction out of the laboratory into the field.There are a number of systems in operation in cement production. It is recognized that on-line mineral analysis has a role in many other processes. This paper presents the technology and invites further discussion should the technology be beneficial to members of the audience.INTRODUCTIONThis article describes COSMA, a system that provides direct and continuous on-line mineral analysis using X-ray diffraction in the field. While X-ray diffraction is a common technique used in mineral analysis, the time from sampling to analysis can be hours and plant operators typically do not get the data in time to control a process or respond to an upset. COSMA provides rapid measurement, analysis and feedback of data, in real time. This provides powerful information that can be used to optimize operation, thereby reducing costs and increasing quality."

Jan 1, 2009

By C. Pelley, S. Kelebek, T. Katsabanis, B. Nanthakumar

"As part of a larger investigation on generation of fines from mining activities and their effect on downstream operations, ore samples from Onaping area stockpiles of Falconbridge Ltd were studied. Batch flotation tests were conducted on the stockpile samples and fresh ore samples to explore the effect of stockpiling on grade-recovery performance. Head grade and particle size distribution of the samples from stockpiles were adjusted so that the samples compared are similar to each other. In additional tests, fresh ore samples were blended with stockpile samples at various percentages, representing 27.4, 50.2 and 81.5% of stockpile samples.The samples from stockpiles produced inferior nickel grade-recovery curves compared to fresh ore. The poorer grade-recovery performance was attributable to two factors. First, a significant dilution effect was observed due to the nearly complete flotation of pyrrhotite. Secondly, while pyrrhotite from stockpiled ore became highly floatable, the same stockpiling conditions caused nickel losses that were attributable to non-floatability of some pentlandite.In the case of blending, there was generally insignificant difference in the nickel grade-recovery between fresh and blended samples when the blending cases involved 27.4 and 50.2% stockpile samples. However, an increase in pyrrhotite recovery was observed for both blending cases. At 81.5% blending case, degraded grade-recovery was significant primarily due to the nearly complete flotation of pyrrhotite. There was a small, but noticeable amount of nickel loss for this case. However, for lower ratios of blending this loss was negligible.The increase in pyrrhotite recovery was partly attributed to its activation by Cu and Ni ions. Formation of a significant amount of elemental sulphur was also apparent from analysis of stockpiled samples. It can be concluded that pyrrhotite is mildly oxidized under stockpiling conditions while part of the pentlandite undergoes a more severe oxidation."

Jan 1, 2006

By G. M. Zhao

The gasification of lump coke with CO2 was studied in a fixed-bed reactor. The effective diffusivity of the gas was evaluated from measurements of the reactivity of the lump coke, produced by BHP Steel in New South Wales, and from kinetic parameters that were determined from the reactivity of fine grains. The grain model of effective diffusion in porous media was adopted to express the gasification rate of the lump coke and was found to fit the experimental data well. The relationship between reactivity and textural characteristics of the coke was examined

Jun 18, 1905

By Erik Westman

Few studies have been conducted regarding the location, movement, and relative magnitude of the rear abutment of a longwall coal mine. The rear abutment, or the abutment pressure arch in the gob area, is controlled primarily by the quality of pack of the gob; the more compacted the gob is, the larger the stress would be theoretically. While there is no definitive location for the rear abutment, early studies showed that it could be located as far back in the gob as 300 m (1,000 ft). Like the location of the rear abutment, there has been little research conducted and very few answers as to the exact magnitude of the rear abutment load. Due to the fact that the rear abutment has been studied considerably less than the front or side abutment, the need for further studies is evident. From a ground control standpoint, the location and magnitude of a rear abutment could reveal information on the caving process associated with longwall mining, such as when the initial cave could be expected to occur in future panels. Besides the possible importance of the rear abutment from a ground control perspective, evidence related to the longwall rear abutment could be vital from a ventilation standpoint. The peak rear abutment location could serve as an area for harmful gases, such as methane, to accumulate because forcing air through repacked rock is more difficult than through loose rock. The objective of this study is to determine whether passive seismic tomography could image the location, movement, and relative magnitude of the rear abutment as the longwall face retreated, in addition to the forward abutment and gob. The results of a passive seismic imaging study at a western US longwall show evidence for the location, movement, and relative magnitude of a rear abutment. A clear zone of highlystressed strata is shown where the forward abutment is expected and a low-velocity, damaged zone is shown behind the face where the gob is located. These two zones retreat with the face over a three-week period. In addition, the images show a return to stress levels behind the gob that are slightly higher than overburden stress levels, which is presumably the rear abutment. This occurs at a distance behind the face that is approximately the same as the face width for this mine. We can conclude that passive seismic imaging can be used to identify the location, movement, and relative magnitude of the rear abutment of a longwall mine. This conclusion is dependent on the use of appropriate data collection and processing methods. The information provided can benefit the both ground control and ventilation engineers as they strive to improve the safety and efficiency of longwall mines. The knowledge associated with the rear abutment of a longwall could not only help increase production through proper initial planning and reduce down time, but it could also make positive strides in improving the overall safety surrounding a longwall mining operation.

Jan 1, 2012

By H. Immink

Keywords: Kyoto Protocol, carbon credits, global warming, energy, auditing Climate change is nowadays being taken increasingly seriously, and the link between global warming and the carbon dioxide released in the generation of energy is coming under increasing scrutiny. The Kyoto Protocol was signed in 1997, after five years of negotiation. So far, about 84 countries have ratified this agreement, under which terms developed countries have strict targets linked to their 1990 level of emissions. However, ?greenhouse gas? (such as carbon dioxide) emissions continue to rise alarmingly. According to the World Resources Institute, greenhouse gas emissions in the USA increased 13% from 1990-2002, while Australia recorded a 22% increase. In contrast, the European Union, a Kyoto signatory, has seen a small decline in its emissions during the same period. This is led by the UK and Germany, who reduced their emissions by 15% and 19% respectively. The concept of ?carbon credits? provides a funding mechanism for companies in the developed world to compensate for some of their CO2 emissions by paying companies (trading credits) elsewhere in the world to undertake projects to bring about reductions in emissions. In the southern African mining industry, it will be possible to get refunded for undertaking voluntary emission-reduction projects. Concern about the environment is creating business opportunities. A preliminary calculation has shown that various projects in South Africa (those in the pipeline, with quite a high likelihood of coming off) could earn a combined total of about R2.5-billion, under the initial phase of the Kyoto Protocol's carbon-credit scheme, which allows developed-country companies to trade credits with developing countries. A number of local companies are planning projects that could comply with the Clean Development Mechanism (CDM), in which they will implement techniques to achieve certified emission reductions (CERs) of greenhouse gases. In order to prevent abuse of such a system involving vast sums of money, vigorous audits need to be carried out. A company has to prove it has made real changes and is not simply conducting business as usual under a cloak of claimed environmental improvements. PricewaterhouseCoopers has applied to become one of only a few international agencies that will be accredited to conduct validation and verification of the credits, by auditing what is called the ?designated operational entity?. An independent validator needs to confirm that the project meets the strict requirements of the Kyoto Protocol. The company has to demonstrate that it?s not business as usual. So, if you refurbished every five years, the next refurbishment is not a good CDM project, unless you can demonstrate that you will do something beyond the maintenance - that is what can be registered. So, Kyoto intends to get additional projects going, and the money for that is actually quite good - prices of 14 euros per ton of carbon dioxide not emitted have been seen. The price depends on who takes the risk for non-delivery if a project doesn?t deliver the emission reductions on time. The highly energy-intensive South African mining industry is heavily dependent on coal. There should be many opportunities for the pyrometallurgical industry to come up with creative ideas to reduce emissions, and there is now an additional financial incentive to encourage this. Companies can actually get money in return for doing these types of projects, in addition to the contribution to corporate social responsibility.

Jan 1, 2006

By Stanley C. Rhoads

The Bureau of Mines investigated the complete ternary system K2 HfF6¬K2ZrF6-l.25 weight-percent HF at 40° C. In addition, solubility curves have been established at 25°, 30°, 500, 60°, and 70° C. These solubility data implemented a study of hafnium enrichment in feed solutions for liquid-liquid extraction processes.. Selected K2HfF6-K2 ZrF6-1.25 weight-percent HF mixtures were equilibrated in a constant temperature bath. Compositions of the equilibrated solutions and wet residues were established from combined hafnium and zirconium oxide and total fluorine analyses. All solubility curves were essentially parallel on triangular coordinates. At 40° C, the solid phase of the K2HfF6-K2ZrF6-1.25 percent HF system is a series of solid solution hydrates with K2HfF6-H20 and K2ZrF6.3H2O segments existing at the respective extremes. Since this system contains K2HfF6-H20 and K2ZrF6.3H20 segments, it is not ideal for simple separation of high-purity K2HfF6 from K2HfF6-K2ZrF6 mixtures by recrystallization. However, it would be useful for producing hafnium-enriched feed solutions from zircon concentrates for liquid-liquid extraction of hafnium from zirconium.

Jan 1, 1973

To maximise recovery by highwall mining, pillars must be designed which are long, slender and of relatively low width-to-height ratios. The strength of pillars with width/height less than 2 depends primarily on the mechanical response of the coal, due to the reduced influence of frictional restraint between roof and floor. A suitable pillar design approach therefore requires a method of estimating coal-seam properties. Experimental studies were carried out to determine ways of reliably predicting the large-scale mechanical properties of coal seams from small-scale test data. The studies led to a method of practical, systematic assessment of coal-seam properties based on measurement of coal rank and seam brightness profiles. The criterion employs the parameters sigma(c), m and s of the generalised Hoek-Brown empirical strength criterion for rock masses. A novel design approach combines the flexibility of modern numerical modelling programs with simple hand calculation for rapid assessment

Jun 21, 1905

By J. H. Jones

The original term of grant No. 1115174 was September 1980 through December 1983. An extended progress report, covering this time period, was forwarded to the Bureau of Hines in January 1984. The principal investigators were given a no-cost extension of their grant to cover the period January through December 1984. The report which follows covers this latter time period only.

Jan 1, 1985

By B. J. Breen, C. S. Mogg

Considerable borehole investigation work has been completed at a proposed site at Sellafield in Cumbria, supplemented by seismic surveys, other geophysical sensing and geological mapping. The focussing of investigation on the rock mass itself will be achieved by means of the planned underground rock characterisation facility, giving access to depths of about 800 m in the strong, low-permeability basement rocks of the Borrowdale Volcanic Group. Characterisation work undertaken during the sinking phase and interaction with continuing surface-based exploration and monitoring should permit a firmer assessment of the long-term safety of a repository. Key considerations in the choice of a design for the repository include the waste handling method, underground inlet cell, underground vaults, vault environment and environmental effects

Aug 1, 1994

By W. P. Yant

[This report describes results of a study bf the carbon monoxide and particulate matter in the air of the Holland Tunnel and metropolitan New York made by the Bureau of Mines (which had participated in the development]

Jan 1, 1941

The production of metallic titanium and titanium-rich alloys in forms useful to the engineer involves the use of certain techniques not usually necessary in fabricating the commoner metals and alloys. However, not all stages in the handling and shaping of titanium-base materials require the application of unfamiliar methods. It is the purpose of this paper to indicate where the well-known techniques are applicable as well as to outline the unusual operations which are necessitated by certain chemical characteristics of titanium.In brief, the characteristics just mentioned are manifestations of the very great reactivity of titanium, especially at elevated temperatures. Liquid titanium burns vigorously when brought into contact with air. It also reacts with practically all refractories, causing damage to the latter as well as undesirable contamination of the metal. Even solid titanium undergoes serious superficial contamination when heated above 800°C. in air for more than a few minutes. In addition to an oxide skin being formed, oxygen enters into solid solution in the surface of the metal causing the latter to become hardened and eventually embrittled.Up to date, titanium has been made only on a pilot plant scale by methods which produce a spongy or powdered product. Refractory problems have prevented the development of chemical reduction methods for making titanium in the form of a liquid pool from which ingots of useful size could be cast. Therefore the first part of this paper will cover the consolidation of powdered or spongy titanium. The latter portion will provide a brief description of...

Jan 1, 1950

By Carlie E. Banks

Tasks during Phase I of this contract effort were performed in four principal functional areas. These were geology, hydrology, reclamation and mining. Data were gathered from literature reviews, mine visits, survey of manufacturers, consultation with government agencies, and unpublished or private communications with contractors and consultants. The data collected were analyzed for omissions or inaccuracies, then organized into tables, graphs and flow charts to provide a concise body of technical and cost data suitable for the engineering analyses required in Phase II of this contract. Maps illustrating estimated grade and thickness of the oil shale were prepared, some of which are included as exhibits to this report. A preliminary mine layout was performed to test the completeness of the collected data.

Jan 1, 1975

By D. Mohapatra

The possibility of using 2,2,4-trimethyl-1,3-pentanediol dissolved in tetrachloromethane as extractant for boron recovery is discussed. The parameters optimized for this purpose are contact time, boron concentration in the aqueous phase, extractant concentration, equilibrium pH and phase ratio. NaOH is used as stripping agent for boron recovery from the loaded organic phase. Boron extraction is found to be a slow process (equilibrium time 20 minutes) compared to boron stripping, which is reasonably fast (equilibrium time 5 min). Maximum boron extraction is possible at a broad pH range from 1.0 to 6.0. Using 1.0M extractant concentration, a 1:1 phase ratio (organic: aqueous) and two stages, ~99% boron extraction is achieved. More than 97% boron stripping is possible using 0.5M NaOH at a 1:1 (organic: aqueous) phase ratio in two stages. Overall, a 95.6% boron recovery was achieved. Loss of solvent into the aqueous phase and co-extraction of Ca, Na and K into the organic phase at higher equilibrium pH are two major concerns in his process.

Jan 1, 2008

This paper describes a mine truck hauling process called "Truck Jigging" which is currently the subject of a process patent application.The investigation explores the production and cost advantages of using the potential energy available in a descending haul truck to assist in elevating an ascending vehicle. Applications are studied for both strip cut mines and open pit operations. Various mechanical connections between the two vehicles are considered, based on a pulley mounted rope system. Fifteen year operating cost estimates show savings of up to 26.5 percent over conventional mine truck operations.

Jan 1, 1989