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By John B. Goodman

A LOW-TEMPERATURE carbonization assay test is described, and factual data derived from this test are presented. The test procedure outlined in this report incorporates a mild-steel retort of improved design, an accurately controlled method of heating, and a complete collection and condensation system for the solid, liquid, and gaseous products of carbonization. The test described establishes, under closely controlled conditions, the relationship of temperature to yields of products on carbonization. Noncoking or weakly coking coals and other carbonaceous material are particularly amenable to testing by the assay. Mass balances of 100 percent± 0.3 are obtainable by this test. It is believed that the efficiency of the test and the accuracy of the type data obtained have been materially increased.

Jan 1, 1953

Kaiser Aluminum & Chemical Corp. announced that it planned to spend $66 million to increase the efficiency of its Baton Rouge, Louisiana, alumina plant. The improvements are designed to reduce energy consumption but will not change the annual capacity of the plant, now rated at about one million short tons. The project was expected to be initiated immediately and be completed by 1982. ALUMINUM Producers in this country posted unalloyed 99.5 percent aluminum ingot at 53-57.5 cents per pound, yet actual selling prices were closer to 53 cents. Domestic merchants quoted unalloyed ingot on a spot basis at 54-56.3 cents. London Metal Exchange 3-month forward contracts fell during November's trading from 55,2 cents to 52.8 cents per pound.

Jan 1, 1978

By T Leach, B Fulton, R Stewart

Gold mineralisation at Porgera is inferred to have been derived from a deep differentiated magmatic source which is capped by a series of (now tilted) inward dipping sills and stocks, which comprise the Porgera Intrusive Complex. An arc normal transfer structure provides a conduit, at tile intersection with an arc parallel structure, into which basic magma derived from tile deep melting of mantle material has been emplaced. Two phases of mineralisation display an association with late stage feldspar porphyry intrusives. Stage I carbonate-base metal-style gold mineralisation occurs as early quartz-sericite, then massive sulphide and late zoned Mn-Fe-Mg-Ca carbonate vein/breccias. Magmatic fluids derived from the deep magma source, are interpreted to have migrated along me margin of a feeder stock to the sills, and south to Waruwari. Stage II epithermal Au-Ag quartz-style gold mineralisation occurs as early fluidised breccias and carbonate veining, followed by zoned quartz-roscoelite-carbonate-gold vein/breccias, and late carbonate and/or sulphate open space infill. Magmatic fluids are interpreted to have utilised the same plumbing system as the late stage feldspar porphyry intrusive, and then migrated into the Roamane Fault which was dilated by; dextral rotation on elements of the transfer structure, normal faulting, and refraction around the competent footwall hornblende diorite. Bonanza gold is localised in a jog in the Roamane Fault, hangingwall splits and at intersections with cross structures. Bulk low grade Stage I gold has been deposited by the mixing of magmatic fluids with cool gas condensate waters, whereas high grade Stage II gold mineralisation resulted from the rapid quenching of mineralised magmatic fluids by oxygenated groundwaters.

Jan 1, 1995

By J. W. Allen

This report reviews the work performed on Task M of Bu-Mines Contract H0220073 to develop an engineering model of a surface and subsurface communications system for normal mine operations and for post disaster rescue operations. The system concept provides for one-way transmission of digital information between a number of identifiable subsurface terminals or subcenters and a single surface station. It also provides 2-way voice communications between the subcenters and the surface station. The basic communications link is electromagnetic signaling through-the-earth, but the system is also capable of using mine phone lines as an alternate link. Engineering models of three subcenters and one surface terminal (see Figure 1-1) have been fabricated in order to demonstrate the system's performance. The system concept, however, permits up to 20 subcenters to be incorporated if desired. Additional subcenters are also feasible for large mines if they can be deployed in the mine to operate on a noninterfering basis.

Jan 1, 1973

By William O. Vanderburg

This paper gives the results of a reconnaissance of the mining districts in Humboldt County, Nev., made during the month of June, 19373/. During the field work, virtually all the mining districts in the county were visited and many data were obtained on a number of active and inactive properties. No attempt has boon made to include in this report all the properties in the various mining districts, and it should be emphasized that whether or not a property is mentioned herein has no being on its merit. The report covers the location of the various mining; districts, types of deposit, information on past operations and current activity, and general information likely to be useful to operators, investors, and others interested in mining. The geology of the deposits is discussed only briefly. The names of the various mining districts mentioned in this report are those generally used when they were organized for purposes of record and regulation. As organized, the districts embraced largo areas with no definite boundaries, and the names have little significance.

Jan 1, 1938

By Patrick Scott, Germán Schmeda, Morgan Mullins, Liam Knudsen, Bradley S. Van Gosen, Carma A. San Juan, Nicholas A. Karl, Jeffrey L. Mauk, Clayton Forbush

The objective of the US Geological Survey’s mineral deposit database project (USMIN) is to develop a comprehensive twentyfirst century geospatial database that is the authoritative source of the most important mines, mineral deposits, and mineral districts of the US. Since May 2017, the project has focused on critical minerals. Data for critical minerals that are produced as products are relatively robust, whereas data for critical minerals that may be recovered as byproducts are commonly of much poorer quality. Similarly, more is known about critical minerals that occur in conventional deposits than where those critical minerals occur in unconventional deposits. For example, rare earth elements occur principally in deposits hosted by alkaline igneous rocks, but there is potential for their production from phosphate rock mining, which is less documented. Lithium (Li) has been recovered from pegmatites and brines, but other Li-bearing deposit types have been delineated that may go into production. Cobalt may be produced as a byproduct or coproduct from a wide range ofmineral deposit types, whereas rheniumis a byproduct of copper ore. Significant opportunities for research exist that could help identify new sources of critical minerals, and may also help increase production and recovery from existing sources.

Feb 8, 2021

By Creelman C. A

The removal of a horizontal piIlar between Nos. 9 and 11 levels (1,116 feet from the collar of main shaft) was successfully carried out by blast hole drilling, and, to the best of the authors' knowledge, this mass blast of 40,000 tons of ore (requiring the use of 7,150 Ibs. of explosive and 5,385 feet of primacord) was the first occasion on which a task of this magnitude has been carried out underground in an Australian mine.Blast hole drilling was introduced by this company approximately fifteen months ago at New Cobar Mine in sub-level stoping.This experimental drilling and blasting gave very valuable information as to the correct technique to be adopted when the final plans were being prepared for the removal of the horizontal pillar at New Occidental Mine.The dimensions of this pillar were approximately 15 feet long, and from 40 to 60 feet wide, and 65 feet in depth.The block of ore extended to 35 feet above the level and 30 feet below, the upper section being partially excavated to form the bell-hole floor and grizzly chambers used for drawing off the broken ore in the shrink stope above the No. 10 level.Description of Ore-bodyThe main ore-body is situated almost vertically in a well-defined shear zone at the junction of sandstone and slate, the sandstone forming the eastern and the slate the western wall.The ore-body consists of highly silicified slate (chert) sparsely impregnated with sulphides, containing a small percentage of copper and bismuth.The total length of the ore-body is approximately 450 feet, with a maximum width of 60 feet in the main section, which is about 200 feet long.This is the section shown in longitudinal and cross-section (Fig. 1).The ore-body is divided by a horse of mullock in the northern end into two legs, the eastern and western, which are approximately 250 feet long and averaging 25 feet in width.This ore-body is strong, hard and abrasive with extremely strong walls, an ideal proposition for open stoping and mass blasting.MiningIn all levels above No. 9 the cut and fill method of ore extraction was adopted. On Nos. 10 and 11 levels the shrinkage method was introduced with economical results, and no difficulty had ever been experienced with shabby or bad walls.Shrink stoping had been carried upwards from No. 11 level to within 10 feet of No. 10 level, when mining hazards developed, and instead of...

Jan 1, 1944

By J. T. Dunham

Zirconium has possible use in industry where severe corrosion conditions are encountered because it resists attack from a variety of corrosive environments. However, very little experimental testing has been done to evaluate the corrosion behavior of zirconium when simultaneously subjected to high tensile stresses and exposed to corrosive environments. This investigation was initiated for an evaluation test, but was limited to environments consisting of ferric chloride solutions which were known to attack zirconium and were shown to promote stress-corrosion cracking in preliminary tests. Tests for cracking susceptibility were conducted by the Bureau of Mines to show the effect of stress, solution concentration, air aeration of solution, and the method of mechanical processing. Tensile stress was applied to the specimens by a constant-load method which proved more reliable than a constant-strain method.

Jan 1, 1961

By Robert H. Peters

How can employees be stopped from engaging in unsafe work practices? It is often easier to prevent employees from performing unsafe acts through manipulations of the work environment than through various training or motivational programs. Therefore, it is important that accident prevention programs seek to identify the reasons for the unsafe behavior and to redesign tasks and the work environment (e.g., tools, equipment, physical surroundings) in order to remove employees from sources of harm and to prevent situations from arising that would prompt them to perform unsafe acts. Unfortunately, in the mining industry the work environment is often innately hazardous, rapidly changing, and difficult to predict, making it very difficult, perhaps impossible, to fully protect the employee by environmental manipulations. Therefore, it is important that effective methods be identified for influencing mine employees to work safely. Various strategies have been used to convince employees to avoid unsafe acts and/or adopt self protective behaviors. The intent of this article is to provide guidance to mine operators concerning the use of four techniques for influencing mine employees to work safely: (1) employee surveys, (2) incentives, (3) fear communications, and (4) disciplinary actions.

By John Watson

New Technologies, New Challenges and New Opportunities For quite some time now, numerous explosive manufacturers have spent untold man-hours and millions of dollars trying to develop a blast initiation technology that would “once and for all” provide users with what was once believed to be only a theoretical possibility...nominal timing. Zero “cap scatter” (the amount of variation of delay timing from the targeted nominal) has been the industry’s goal ever since delays were first introduced into the marketplace. Just as adding delay time between blast-holes improved blast performance since their introduction, having the wrong delay or a poorly timed blast has proven to be very inefficient and in many cases hazardous. The question of how precise a blast initiation system needs to be still remains unanswered, but electronic detonator systems being used today indicate that significant improvements can be achieved over conventional pyrotechnic detonators. These systems can typically provide single digit millisecond ranges of variability, if not sub-millisecond in some cases.

Jan 1, 2003

The conclusions reached by den Tex after a study of the fabric of some rocks from Broken Hill have been used to support the epigenetic hypothesis for the origin of the ore, first by Edwards (1959, p. 70) and then by Stillwell (1962, p. 131) in his criticism of Segnit's (1961) views. Den Tex claimed that the petrofabric study provided "independent evidence that the ore, at least in its present form, post-dates all events of a diastrophic nature in the area concerned".Repetition of this claim by Edwards and by Stillwell and the lack of any criticism of den Tex's work for more than three years implies its general acceptance by geologists in Australia. Therefore it appears necessary to examine parts of den Tex's paper in detail to show that his, conclusions are unwarranted. The major weaknesses in his study are that1. the petrofabric study was inadequate to warrant any major conclusions, and2. the petrofabric data allow alternative conclusions.Den Tex made a single visit to the field, collected six carefully selected specimens and presented quartz and· biotitepetrofabric diagrams for two specimens, quartz-diagrams alone for three more and included three diagrams of the orientation of c-axes and fractures in one specimen. It is not reasonable to come to firm conclusions about the origin of such a complex area as Broken Hill on such inadequate data, despite den Tex's claim (p. 87, lines 22 and 23) that "a thorough investigation of the quartz-fabric of the wall rock was undertaken".Den Tex's interpretation of each diagram is open to criticism, and alternative (and to my mind, preferable) interpretations may be made. It is impossible to evaluate den...

Jan 1, 1962

By P K. Banerjee, S Kumar

Indian iron ores with less than 62 per cent Fe are currently unexploited, except for a few sectors which export them to foreign countries. It is anticipated that by 2012 the countryÆs domestic steel production is likely to rise to the tune of 60 million tonnes per annum. To meet this requirement, it is necessary to utilise not only the existing high-grade deposits but it is also necessary to look into exploiting the leftover iron ores of lower grades. Hence, reserves with Fe content 62 per cent and below (particularly the ores with In the present paper, an attempt has been made to beneficiate three different types of low-grade iron ores selected from three different parts (states) of the country. In the paper, alternative routes for beneficiation and effective utilisation have been tested using different techniques in the laboratory in an attempt to match their (Al2O3/SiO2) ratio after thorough characterisation and liberation studies. The paper also encompasses the geological formations, occurrences and distribution of Indian iron ores as well as highlighting the problems associated with the fines, possible metallurgical routes, and their market segregation from the perspective of end users.

Jan 1, 2007

By J. N. Van der Merwe

"A major shortcoming of the statistical back-analysis of coal pillar strength is that it relies on the asmined pillar dimensions, not taking into account time-related pillar scaling with subsequent reduction in pillar width. The paper describes an investigation where the rate of pillar scaling was applied to the pillars in the databases of failed and unfailed pillars. The reduced pillar sizes were then used in the same method of statistical back-analysis that had been used in the past.This resulted in an equation for pillar strength which predicts significantly greater pillar strength than the previous statistical analyses, which is similar to the strength which had been found earlier by direct testing of large specimens underground. It is concluded that the lower strengths found by previous statistical analyses are due to the incorrect pillar width being used and that by adjusting the pillar sizes to compensate for scaling, more credible results that correspond to direct testing are obtained.As the newly derived strength equation is time-dependent, it follows that the safety factors and probabilities of failure are likewise time-dependant. An equation to determine the probability of failure is also developed. This results in the safety factor being close to unity at a probability of failure of 50%, which is aligned to statistical expectation. IntroductionSince the Coalbrook mine disaster, caused by massive pillar collapse, there have been several attempts at analysing and defining the strength of coal pillars. It was realized in the very beginning that performing classical strength tests on coal specimens in a laboratory and then transferring those results to real coal pillars could not be successful. The scatter of results is one problem and, more seriously, there is a size effect (at least for small specimens) that made the transformation of strength results to much larger coal pillars underground all but impossible.Two main schools of thought then emerged. Some researchers preferred to perform direct strength tests on large specimens underground, while others relied on statistical back-analysis of failed and unfailed pillar cases, attempting to determine the differences in size and shape that would allow a satisfactory prediction of failure. The latter school of thought resulted in the method that was widely accepted by the South African coal mining industry, described in the landmark publication by Salamon and Munro (1967)."

Jul 1, 2019

By Herbert Haas

The Bureau of Mines is endeavoring to reduce waste and increase efficiency in the production, refining, and utilization of petroleum . During the last few years the demand for petroleum and its products has increased so much more rapidly than the production that greater efficiency in utilization is now a matter of most serious importance . The Diesel engine, a comparatively new type of internal-combus- ' tion engine, is an important device for insuring more efficient utilization of petroleum and coal-tar products, for it consumes heavy liquid fuels such as can not be utilized in other types. Like the gas or the gasoline engine, it is revolutionary within its province. For some uses this engine is replacing gas and gasoline engines , but its most important duty will be to replace the wasteful consumption of fuel oil in steam engines. Not only will a wider use of the Diesel engine relieve the demand, but it will result in more power being obtained from the same consumption of fuel oils . In spite of these advantages, comparatively few Diesel engines are in use in the United States . In this report the author discusses recent developments in the design and construction of the Diesel engine, the fuels suitable for burning in it, and the uses to which it is particularly adapted .

Jan 1, 1918

By H. Foster Bain

The war has brought about many changes in the Western States, and some have deep pr sent or potent al economic significance. The West has been feeling severe growing pains for a number of years. Especially since the beginning of preparation for national defense and through the period of

Jan 1, 1945

By Steven E. Mischler, Jay F. Colinet

The study analyzes the impact of the Continuous Personal Dust Monitor (CPDM) on reducing overexposures to coal mine dust. It compares compliance sampling data before and after the implementation of the CPDM and the 2014 MSHA dust rule. The results indicate a significant reduction in the percentage of samples exceeding the dust standard for various mining occupations, highlighting the effectiveness of the CPDM in improving miners’ health and safety.

Feb 22, 2022

By C. P. Bowie

For years many oil producers have believed that often low-pressure oil- and gas-bearing strata have been over coked in fields where the rotary system of drilling has been used. Collom3/ gave as a reason for this con¬dition that because the mud fluid was thick, the oil or gas stratum was plastered and sealed as the tools passed through it and no oil showed at the surface. Although this observation was made 15 years ago, it may often still be true notwithstanding modern developments in coring and electrical logging. Operators have believed, also, that mud fluid does not solidify behind the casing. Lewis and McMurray4/ stated: "All the evidence obtainable from practical experience points to the fact that the mud fluid properly mixed and employed does not solidify behind the casing, even in deer wells and after long periods."

Jan 1, 1937

By Oliver C. Ralston

The Nonmetals Division studies problems relating to the use of minerals, many of which are important to national defence for purposes other than the extraction of metals. In fact, virtually all of the work of the division has been diverted to investigations pertaining to better use of the Nation's natural nonmetallic is resources as weapons of defense. The experiment stations of the division are at Norris, Tenn.; Tuscaloosa, Ala.; Seattle, Wash.; and College Park, Md. Studies involving the application of electric power to the nonmetallic minerals are conducted at the Electrotechnical Laboratory at Norris, and investigations on mineral-dressing treatment are conducted mainly at the Southern Experiment Station at Tuscaloosa. The cleaning and preparation of coal are studied at both Tuscaloosa and the Northwest Experiment Station Lit Seattle (other projects relating to utilization of coal are conducted by the Coal Division of the Bureau of Mines). Problems covering the use of minerals and fundamental problems as to their properties are studied at College Park.

Jan 1, 1941

By Alastair M. Lumsden

A study was initiated to examine the ways in which a number of foreign countries classify and regulate metal/non-metal mines which experience problems due to naturally-occurring flammable gases. Twenty countries were selected for study, and useful information was obtained from sixteen of these. Nine countries were visited (five of them twice) to hold meetings with representatives of government mine regulatory agencies and mine operators, and to visit mines encountering methane and other gases (carbon dioxide, nitrogen). In the later stages of the study seven gassy metal/non-metal mines in the United States were visited so as to provide a basis for comparison, and hence the evaluation of both the U.S. and foreign gassy mine regulations. In addition to obtaining copies of the mining laws and regulations of a number of foreign countries, nine foreign gassy mines, and the seven in the United States were documented in as much detail as possible. All this information is presented, along with appropriate conclusions and appendices. The study took two years and three months to complete.

Jan 1, 1983

By Wagner Angelo da Silva

A crescente demanda por energia elétrica nas aeronaves modernas pode ser constatada pelo aumento da potência elétrica gerada a bordo, como exemplo o Boeing 787 produz 1000kVA, 200V trifásico, 400Hz variável contra 240kVA, 200V trifásico, 400Hz fixo produzido pelo Airbus A330, apesar de possuírem aproximadamente as mesmas dimensões. Devido à necessidade de redução de massa de transformadores, a frequência utilizada na geração de eletricidade na aeronave é de 400Hz o que acaba produzindo um aumento das perdas em núcleos de FeSi destes transformadores, principalmente pelo aumento das correntes parasitas no núcleo. Transformadores elétricos com núcleos de ligas amorfas a base de Fe vêm apresentando redução de até 70% das perdas no núcleo quando operados em 50Hz ou 60Hz. Assim, esse estudo visa discutir as vantagens e desvantagens do uso de transformadores elétricos com núcleos de ligas amorfas a base de Fe em aeronaves. Os resultados mostram que, com o desenvolvimento de novas ligas, tal utilização mostra-se viável devido a uma redução de peso de tais transformadores.

Aug 8, 2018