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By V. F. Parry

The object of this report is to present certain pertinent data on the physical and chemical properties of South Arcot lignite and to present the results of several special tests to show how the raw lignite can be upgraded to superior fuels for certain special uses. The Bureau of Mines Branch of Coal Technology laboratories at Denver have advocated the drying and carbonization of all low-rank fuels for special uses and have introduced and developed new techniques for upgrading and refining noncoking coals. Application of these techniques to the South Arcot lignites was the object of the investigation, and this report presents significant data necessary for planning a fuel program based on utilization of dried and carbonized dusts. In general, the South Arcot lignite is similar in chemical properties to the high-moisture lignites found in the United States and has some physical properties similar to Australian brown coals. The samples submitted for test had lost moisture before delivery to the laboratory, and it has been necessary to estimate the analysis of the lignite in place in the mine. Various observations made in India by qualified technicians indicate that the bed moisture content of the entire seam is in the range of 54 to 56 percent. For estimating purposes in this report, the bed moisture content has been taken as 56 percent and the ash content of the fresh coal as 2.5 percent. The average analysis estimated for the as-mined lignite is: [Moisture percent 56.0 Volatile matter do.22.0 Fixed carbon do.19.5 Ash do.2.5 Heating value B.t.u. per lb. 4,890]

Jan 1, 1957

By Michael J. Beus, Jan G. Patricio

INTRODUCTION The U.S. Bureau of Mines, Spokane Mining Research Center, has been conducting and documenting rock mechanics research in the Coeur d’Alene mining district for the past ten years (1, 2, 3, 4, 14, 15). A current project combines the information gathered from rock mechanics instrumentation, geologic structure, and analytic techniques to improve shaft and support design for the deep mines of the district (3). This project required knowledge of the anticipated loads and the physical properties of the rock mass to provide accurate input data for computer design models. Several techniques have been utilized to determine the physical parameters including the USGS (U.S. Geological Survey) solid inclusion probe, the CSIR (Council for Scientific and Industrial Research) biaxial and triaxial strain cells, and the CSM (Colorado School of Mines) dilatometer. This paper describes the determination of the in situ modulus of deformation in three mines over a period of three years and the evaluation of these results as they applied to this project. The need for in-situ rock mass properties such as the modulus of deformation has stimulated research and development of a large number of instrumentation techniques. One area of continuing interest involves various methods of radial borehole dilation. This concept was pursued by Menard (9) with an apparatus known as the pressure meter, which is used frequently in soil mechanics. Other developments in rock mechanics include the CPC (cylindrical pressure cell) by Panek (11) and the dilatometer by Rocha et.al. (13) in Portugal. The CSM dilatometer, which also utilizes this technique, was chosen for this project because it required a small amount of background study, was inexpensive, and could easily be combined with other experiments being planned for the test locations. Although no previous field applications to hard rock (compressive strengths greater than 20,000 psi) has been documented, the instrument was selected since good results have been achieved in granite, oil shale, and several coal measure rocks (11, 12).

Jan 1, 1977

By C. A. Fisher

THE Salt Creek Oil Field of Wyoming occupies a unique position among the major oil fields of this country. Many years before the beginning of actual production in this area, in 1911, it had attracted country-wide attention as a district holding oil possi¬bilities. Even foreign capital, mainly French and Belgian, had sought out this district as having oil values and spent many thousands of dollars 'in an effort to acquire property rights' in this field which was very largely located on the public domain. Owing to inadequate laws governing the acquisition of oil lands on the Federal domain and a careless practice having grown up among oil land locators of that time, a complicated title situation quickly developed in Salt Creek. This condition of uncertain titles together with the isolation of the field from industrial centers were doubtless the two most potent factors in retarding its early development. After actual production began in 1911 governmental regulations, suits between the government, and the locator, disputed ownerships between locators and claim and counterclaim continued to retard the field's development. It is believed that the title situation in the Salt Creek Field, where potential values of such magnitudes were involved, was responsible more than any other factor for the ultimate passage of the government leasing act in 1920 affecting all oil lands on the Federal domain.

Jan 1, 1925

By Serge Rudchenko

A study to determine the potential use of retaining structures in open pit backfilling. Research and review of the open pit mine environment, mine waste disposal, and past and current use of retaining structures. A development of specific structures, the culvert/ tunnel concept, and an anchor block retaining concept. The cost benefit of retaining structures used for in-pit backfilled waste.

Jan 1, 1981

By Walter Koellner

Today?s large electric mining shovels are significant users of power and represent peak loads of more than 3.5 MW to a mine?s distribution system. The power swings during normal operation can influence the line voltage at the Point of Common Coupling (PCC). The static converters for the shovel?s motions also create voltage and current harmonics which are fed back into the mine?s power grid. In addition, shovels themselves are affected by the power quality of the mine?s distribution system. This paper introduces the use of active IGBT rectifiers, also called Active Front Ends (AFE), as alternative to conventional, line commutated SCR thyristor rectifiers. The AFEs convert the AC line input into a controlled DC-link voltage. This DC voltage is then used as input to IGBT inverters, which power the AC motors of the shovel?s Hoist, Propel, Crowd, and Swing motions. The introduction of AFEs creates the following operational improvements: i) reduction of the Harmonic Current Distortion THDi from more than 40% to less than 4%; ii) full regenerative operation; iii) the potential for line voltage stabilization at the PCC; iv) high tolerance for line voltage fluctuations; v) improved dynamic performance, and, as result vi) higher availability and productivity of the shovel.

May 1, 2001

By Raymond A. Binns

The Eastern Manus Basin (EMB) contains three major active hydrothermal zones and a number of smaller occurrences of hydrothermal deposits, and can be considered as a regional-scale modern analogue for volcanic-hosted mineral fields on land. Unlike the central Manus Basin, a back-arc spreading zone with some MORB-like basalt-hosted massive sulfide deposits, the EMB is a pull-apart rift zone between two transform faults, where a basement of Eocene-Oligocene arc crust is being thinned by extension, with rapid sedimentation on the tilted fault blocks. Present-day submarine igneous activity in the EMB, with which hydrothermal activity is associated, has arc geochemical affinities and is related to subduction of the Solomon Sea Plate at the New Britain Trench. Overall, hydrothermal deposits in EMB are found with lavas ranging from picritic basalt to rhyodacite in composition, although the two major occurrences of massive sulfide are hosted by the more siliceous dacite and rhyodacite variants. Some volcanic edifices are central eruptions, mostly of porphyritic lavas or domes, while others are elongate ridges formed by fissure eruption in which the typically aphyric lavas were very fluid. Evidence for shallow-level fractional crystallisation controls of lava chemistry implies presence of subjacent differentiated intrusions or former magma chambers. Seismic tremor at one site during the nearby 1994 Rabaul eruption suggests magma movement in the chamber.

Jan 1, 1998

By G. W. Jones, R. E. Kennedy

"INTRODUCTION In the manufacture, storage, transportation, and use of combustible gases and vapors, explosion hazards, which at times may be present when air becomes mixed with the gases and vapors, become of primary importance. Such conditions are especially dangerous where large volumes of gaseous atmosphere are involved, because an explosion under such circumstances is capable of doing tremendous damage to both property and personnel.Because of its interest in safety in the mining and allied industries, the Federal Bureau of Mines has investigated, and published results dealing with, the explosibility of various types of combutible atmospheres. The explosion hazards of natural gases have received attention, and results giving the limits of inflammability and ignition temperatures in air have been determined and published. 4/ Other investigations have shown how explosions of natural gas-air mixtures may be prevented by the addition of nitrogen and carbon dioxide. 5/Because of the increased demand for crude oil for war purposes, the application of secondary-recovery methods of stimulating oil production have received considerable attention during the last few years. The process consists in the injection of natural gas into partly depleted oil wells to cause the oil in the sands to flow into producing wells and so increase the amount of recoverable oil. 6/"

Feb 1, 1945

By Walter R. Storms

"The New Mexico potash exploration described herein was begun in February- 1944 by the Federal Bureau of Mines with the object of determining the amount of potash ore in the United States Potash Reserve in Eddy County, N. Mex., by exploring the deposit from the surface with vertical drill holes. The work was completed in October of the same year after 16 holes had been drilled on the reserve and in the immediate vicinity.The Potash Reserve is located in secs. 26, 27, 34, and 35, T. 20 S., R. 29 E., Eddy County, N. Mex., about 14 miles northeast of the city of Carlsbad. Drilling was done in secs. 26 and 35 of the reserve, in sec. 14 to the north, and secs. 25 and 36 to the east. All work was done on Government-owned, unleased land.The reserve may be reached from Carlsbad by traveling northeast by automobile for about 14 miles on paved U. S. Highway 62. This highway passes through the southern part of the reserve. Other parts may be reached by a State highway which passes along the eastern side of the area, then by poor dirt roads to various drilling sites. A branch of the Atchison, Topeka and Santa Fe Railroad also passes across the southern part of the reserve en route from Carlsbad to the plant and mine of the Potash Co. of America, a few miles northeast of the Project and 22 miles from Carlsbad.Work on the project was greatly facilitated by the help of Ralph H. King, associate geologist, R. K. Bailey, geochemist, H. C. Spicer, geophysicist, Hope Bunker, junior geologist, and R. H Allport, district mining supervisor, all of the Federal Geological Survey; and Charles H. Johnson, who at that time was district engineer for New Mexico for the Mining Branch of the Bureau of Mines."

Apr 1, 1946

By Richard G. Stearns

Extensive thick lignite apparently lies within 250 feet of the land surface in Dyer, Lake, Lauderdale, Obion and Tipton counties. Information on geology, land use, soils, groundwater and instability is compiled, along with a bibliography. A test and monitoring site was investigated at Fort Pillow Prison in Lauderdale County. Analyses were made of lignite, overburden, associated water and leachate. Lignite has high BTU (about 7800) and low sulfur (1.1% avg.). A year or more of data are presented on rainfall, water levels, and chemistry of surface water, groundwater, leachate and water from test pits. Main potential environmental problems are quality of surface water, and possibly shallow groundwater. The main aquifer of the region will likely be un-affected by mining. Low transmissibility of shallow aquifers will minimize lowering water levels of wells. Soil reclamation and conservation should be readily accomplished, Dangerous earthquakes have a low probability and mines are not significantly more hazardous than steep bluffs.

Jan 1, 1981

By Thomas Gales

Longwall mining of thin shallow coal seams utilizing open pits is technically feasible. The thinnest coal seam which can be mined using available technology is 34 inches. The capital expenditure for a 1,000,000 ton per year operation is $15,494,000, and the projected rate of return is 5 percent. Similar statistics for a conventional area surface mine are S18,937,000 capital and 14 percent rate of return. The longwall surface mining method disturbs 63 acres of land per 1,000,000 tons, and the conventional area surface mine disturbs 198 acres A significant bibliography of the technology involved is included.

Jan 1, 1976

By MATT RENAUD, Mustafa Kumral

As high-quality mineral deposits are thoroughly exploited, mines of the future will have to move towards more remote and lower quality projects. With these projects comes an increased business risk to the operator. Even now, mining companies often turn to foreign countries for new deposits to produce, introducing the concept of country risk into their portfolio. Furthermore, feasibility studies often fail to accurately quantify the risks associated with various projects, and as such, this study proposes a technique of risk quantification which can both aid mining companies to evaluate the viability of investment and assist in risk disclosure to public investors for the mining industry of the future. This paper aims to quantify the effects of country risk on the valuation of potential mining projects, using a combination of modular and risk-weighting techniques to evaluate the country risk premium (CRP) required to obtain capital for operation of risky foreign mining projects. The techniques proposed in this paper are demonstrated using fictional examples and then evaluated for accuracy against a recently developed debt-funded precious metal project in a country in the Americas.

Sep 30, 2021

By S. S. Venkata

This volume describes a comprehensive program of research into the reliability of mine electrical power system components and the resultant reliability of the total system. The research effort encompassed analytical models, laboratory testing and field testing. The analytical work included definition of terms, fail rate functions and distributions, failure rate estimation and techniques and procedures for theoretical reliability assessment. One of the primary mine power system components addressed in the study was the ac molded case circuit breaker. This device is known to have low reliability and hence an unfavorable impact on mine safety and productivity. Ac molded case circuit breaker reliability was studied by analytical means, laboratory testing and field monitoring. A similar three-pronged' effort was made to study the reliability of undervoltage relays/releases. Particular emphasis was placed on new solid state undervoltage relays. The reliability of bulk power components, such as trailing cab les, motors, control gear, and other equipment, was assessed by gathering maintenance records from active mines. These data were compared to similar records from other industries. The work was extended to include the reliability, availability, maintainability and safety of these components.

Jan 1, 1979

By D. L. H. Forbes

(New York Meeting, February, 1912.) Introduction.. THE application of the cyanide process to complex sulphide ores for the extraction of their bold and silver is no longer a novelty, but, as an example showing modern tendencies in this direction, the following description of the new milling process at the Lucky-Tiger mine is offered: The extraordinary richness of the ore in the upper workings of this mine made any thought of milling in its early hays seen unnecessary. Its location in an almost inaccessible part of the rugged mountains just south of the Arizona boundary-line, and 60 miles from the town of Douglas, made the expense of bringing in machinery and supplies a very serious consideration. But, after the property had been shipping high-grade ore on mule-back for a few years, there remained in the mine a considerable tonnage of vein-matter that was too low in value to ship, but which it was thought could be milled near the mine at a profit. The first milling-experiment consisted in the installation of Nissen stamps in conjunction with concentrating-tables and Frue vanners, but, as the ore from the upper workings contained most of its silver in the form of cerargyrite, this type of mill was not successful. The proximity of the mine to the great copper-concentrating mills of Cananea and Moctezuma naturally made the influence of copper-milling, ideas felt in the company's next installation. At considerable expense a stage-crushing concentrating-mill, with a capacity of 100 tons per day, was built. This mill was modeled along the lines of the most approved practice in copper-concentrators at that time, the main idea being that crushing by stages in rolls was necessary in order to prevent losses from ?sliming." Largely owing to the fact that, when the mill

Aug 1, 1912

By C. Meyer, J. J. Eidel

C. W. Hunt I wish to register strong disagreement with the choices of drilling sites chosen by the Continental Scientific Drilling Committee, while endorsing the stated objectives. Of special significance is the lack of any site involving the metals most needed today in the US, while 9 to 13 km of drilling are allocated to gold and silver districts and 11 to 17 km to base metal (mainly copper) districts. Why is nothing proposed for platinum group or chromite? Is this because the committee did not know of such a site? If so, I offer such a site in California (see Fig. 1). The mineralization shown in Table 1 occurs in a large peridotite body in western Tehama County, CA. Petrography has demonstrated unequivocal evidence of migrated PGE deposited in peridotite and chromite of hypabyssal nature. Active diapirism (due probably to serpentine buoyancy) above a reactivated mantle to surface conduit marks the position of the conduit. Young explosion breccia cemented loosely by volcanic glass and tuff demonstrates the significance of the conduit as the prime source of the various emissions. Deep drilling could result in major metals discoveries as well as shedding light on the grand questions of platinum group mineralization. What role water has played in this occurrence is not yet certain; but chlorine and asphaltite have been detected in and adjacent to native PGM, suggesting a major role for water. The explosion breccia suggests that this excellent site could overlie entrapped geothermal steam.

Jan 6, 1987

By Cipriano Colqui Robles

El presente texto refiere la importancia de las funciones del supervisor en la prevención de accidentes -en tanto sea conciente de la responsabilidad que dicha labor le atañe-. En este sentido, el supervisor debe cumplir fielmente las normas de seguridad, convirtiéndose en un buen ejemplo para el grupo en el que está a cargo. La responsabilidad se extiende también a las relaciones que existan entre su departamento como el de los demás, así como de la disciplina y del desarrollo de las actitudes hacia la seguridad y bienestar de los trabajadores, la empresa y el país mismo.

Aug 20, 1965

By Ian McFeat-Smith

Despite a present, short-term economic recession, a remarkable enthusiasm exists in Hong Kong for building infrastructure including major tunnel projects. This paper provides details of current and recent bored tunnel works together with an insight into the impressive list of future underground projects planned by the MTRC,KCRC, Highways Department and Drainage Services Department for the next decade. Risks for each of these works including pipejacking, mixed face and rock tunnelling generally in Hong Kong are also identified. From this is evident that the scale and difficulty of such works continues to increase, requiring the use of more sophisticated methods of construction, the need for better methods of assessing and managing risks and for Government to utilize improved, more equitable Conditions of Contract for such major tunnelling projects.

Jan 1, 2001

By Charles Camsell

At the Annual General Meeting of the Institute in 1924. I endeavoured to present the position held by the mineral industries in the commercial life of this country. The facts and figures were presented at that time in a detached way. Since then, however, I have made some attempt to analyze them in order to determine the causes for that position and to draw some conclusions as to the future of the mining industry. As everyone knows, our trade figures are very often used in political discussion, especially in discussion of tariff policy. It would be entirely out of order for me to say anything touching the tariff issue and I want to have it clearly understood that, in my opinion, the material I am about to present contains not a single statement or conclusion which anyone would be warranted in using as an argument for either a lower or a higher tariff or for tariff changes of any kind. As a starting point, let me re-state, very sketchily, Canada's general situation in external trade. In the last calendar year, 1924, we sold Canadian merchandise of all kinds to other countries to the value of $1,045,000,000 in round figures. Our purchases abroad reached about $893,000,000. Thus our sales exceeded our purchases by roughly $152,000,000. In other words, we had what is known as a 'favourable balance of trade' - one of the biggest favourable balances we have ever had in our history. The proceeds of our sales of Canadian products enabled us to meet the bills for all our purchases of foreign commodities and, in addition, placed a large surplus to our credit with which to offset our interest charges and other obligations abroad.

Jan 1, 1925

By Giorgio Franceschetti

Explicit expressions are presented for the input admittance and effective height of several buried metal antennas, namely: (i) prolate spheroidal; (ii) spherical; (iii) oblate spheroidal; (iv) parallel plate; (v) parallel plate with protruding dielectric in the same plane of the plates; (vi) parallel plate with protruding dielectric in a plane normal to that of the plates (H-shaped antenna). Explicit expressions are presented for the input admittance and effective height of several buried metal antennas, namely: (i) prolate spheroidal; (ii) spherical; (iii) oblate spheroidal; (iv) parallel plate; (v) parallel plate with protruding dielectric in the same plane of the plates; (vi) parallel plate with protruding dielectric in a plane normal to that of the plates (H-shaped antenna). It is concluded that in all practical situations of "small" antennas approximation 1 is almost always appropriate. Computations were carried out for bare antennas, the extension to insulated ones being, however, straightforward. Although a rigorous theory of the antenna performance in a realistic semi-infinite conductive medium has not been developed, the results quoted should also be applicable when antennas are a few skin depths below the earth's surface. In particular, for the evaluation of radio-links under up-over -and-down operating conditions, the antennas can be replaced by dipoles of length equal to the effective height. Since the antenna's parameters are given in analytical form, it is also possible, by using Laplace transform techniques, to compute the transient response of the antenna. The transient is described by pole (short-time behavior) and branch-cut contributions (large time behavior). For these last terms, an asymptotic evaluation is possible, so obtaining closed form expressions for the response at large observation times, which is closely related to the dispersion characteristic of the environment.

Jan 1, 1973

By Paul M. Tyler, R. M. Santmyers

Platinum and its allied metals osmium, iridium, rhodium , palladium, and ruthenium are the most costly of the better-known metals and combine properties that make them unique among the elements . For a number of isolated uses substitutes have been found which are cheaper and quite as satisfactory ; but none will replace platinum in many of its varied uses , and there is a large and growing demand for purposes for which no economical substitutes are known . As this paper is being written the supply of platinum tends further to increase as a result of the exploitation of newly developed resources and the expansion of production from older sources . In obedience to economic law prices have declined steadily . Buyers , always reluctant to commit themselves on a falling market , have maintained a waiting attitude , and consumption trends are not clearly indicated . Should platinum again approach the price of gold , the natural tendency would be to use more of the metal . In recent years , however , the industrial and scientific uses of platinum have become subordinate to its consumption in jewelry . In matters of personal adornment the popular whim and not practical utility is the dominant factor in demand , and it does not follow that lowered prices will stimulate demand . The substitution of white gold and certain plated goods for platinum may be checked by cheaper platinum , but a fickle public that turned from gold to platinum when platinum became the more costly metal can not with certainty be expected to buy more platinum jewelry because more of the metal than formerly may now be had for the same price . The dearth of platinum during and for some years after the World War had a profound effect upon prices , and this in turn wrought important changes in the field of consumption . When prices advanced the chemical industry, formerly the leading consumer of platinum, was forced to economize in its consumption of the metal and to substitute other metals whenever it could . Somewhat similar conditions resulted in the electrical industry and in the use of platinum in dentistry . Some of these former outlets are permanently closed , and others may be reopened now that platinum prices have receded to pre-war levels , but despite the general expansion of industrial and scientific activity since 1913 the demand for platinum outside the jewelry trade has suffered a net decline . Since the metallurgy of platinum is relatively simple the reason for its high price is its relative scarcity in the earth's crust . An interesting speculation set forth by certain geologists attributes the extraordinarily high density of the interior of the earth in part to the presence of iron alloyed with substantial amounts of platinum and other related metals . In support of this hypothesis it may be said that platinum is often found in meteorites , and known deposits in the earth's crust are all of deep - seated origin . However , even if there were a high concentration of platinum in the interior of the earth it would be next to impossible at the present state of our knowledge to make it available , and the world would continue to depend for its supply on deposits found within minable depths below the surface . For many years before 1914 the world obtained its supply of platinum metals primarily from Russia , which before the war produced as much as 300,000 troy ounces in a year , or approximately 95 per cent of the world output . Despite fluctuations due to internal political disturbances Colombia managed to account for 3 to 4 per cent , leaving the rest of the world to furnish the remaining 1 to 2 per cent .

Feb 1, 1931

By G. R. Hopkins

Although many small refineries were dismantled in 1934 the total number of plants, including a few under construction, increased from 604 at the beginning of the year to a new high of 638 on January 1, 1935. The capacity also reached a new record, the total of 4,072,400 barrels of crude oil daily being about 45,000 barrels higher than the previous high of January 1, 1932. The number of refineries increased materially in 1933, following construction in east Texas and the building of many small plants in the Rocky Mountain district and elsewhere. Most of the new plants of 1933 were built to provide an outlet for crude or because the ratio between crude oil and gasoline prices appeared conducive to profits However, low gasoline prices and increased costs in 1934 dispelled the hopes for profits; many plants were shut down, and some were dismantled. The number of operating plants declined from 454 on January 1, 1934, to 435 on January 1, 1935, but the number of inactive plants increased from 137 to a new high of 196 during the same period. As indicated above, new construction was at a minimum in 1934, and on January 1, 1935, only 7 plants were being built.

Jan 1, 1935