Search Documents

By H. B. Jensen

STUDY of the thermal-solution process was begun by treating crushed oil shale in a small autoclave at temperatures of 700° to 950° F. The effect of temperature, reaction time, type of solvent, and richness of shale upon the amount of organic matter that was removed from the oil shale was thus determined. Following this orientation work a semicontinuous, bench-scale apparatus was built so that heated solvent could be pumped through a bed of shale under elevated pressure, thus removing the converted organic matter from the spent shale. After some operating experience had been gained, a continuous unit was constructed. This permitted treating a slurry of shale oil and pulverized oil shale at about 300 p. s. i. and temperatures of 750° to 850° F. for various retention times. Considerable cracking and polymerization of the shale oil were found to take place during the process. In an attempt to prevent this, a study was made of extraction of the shale in batch-type autoclaves under high partial pressures of hydrogen at total gas pressures of as much as 4,300 p. s. i. at 850° F. The thermal-solution process was found to convert over 90 percent of the organic matter in oil shale to oil and gas. The highest yields of gas and oil obtained without hydrogen pressure were equivalent to 119 weight-percent of those obtained from the same shale by Fischer assay. With a high partial pressure of hydrogen, yields equivalent to 126 weight-percent of Fischer assay were obtained. However, the oil produced by thermal solution has a higher boiling range than that obtained by other retorting methods, particularly so if the thermal-solution process is used without a high partial pressure of hydrogen. Nondistillable oil (all benzene-soluble material that would not distill under 2 mm. Hg absolute pressure without cracking) equivalent to over 100 percent of the organic matter in the shale was obtained without hydrogen pressure in the system. When the process was carried out under hydrogen pressure, the yield of nondistillable oil amounted to 60 to 70 weight-percent of the organic matter. Part of this heavy material is formed partly by polymerization and condensation of the shale-oil solvent used. These reactions, as well as cracking of the solvent to form gas and a carbonaceous deposit on the shale, are unfavorable features of the process.

Jan 1, 1953

By Bertha R. Klahold

"In response to numerous inquiries regarding tests and analyses of minerals and related inorganic materials; Bureau of Mines Information Circular 6999, ""Laboratories That Make Fire Assays, Analyses, and Tests on Ores, Minerals, Metals and Other Inorganic Substances,"" by C. W. Davis and M. W. von Bernewitz, was published .in 1938 and revised in 1939 (I. C. 6999R). In this paper on analytical and testing laboratories, the original text has been rewritten and expanded, and a table has been added, in which are listed laboratories prepared to offer a number of special testing services in addition to ordinary assays and chemical analyses. The arrangement of laboratories on, a geographical basis has been maintained.This circular is compiled as a public service, and none of the laboratories listed herein is recommended over any other,These lists were compiled from questionnaires sent to organizations whose work is connected with mineral and metallurgical testing. The response in general was very satisfactory, and the author takes this opportunity to express her appreciation to the officers of the listed laboratories for their cooperation.Acknowledgment is also made of the valuable assistance of the members of the technical staff particularly Morris Slaving/ of the Eastern Experiment Station of the Bureau of Mines at College Park, Md., in the preparation of the questionnaire and technical descriptions.Many mineral samples are sent to government agencies in the National Capital with the request that they be assayed or chemically analyzed. It should be emphasized that there is no place in Washington D. C. where assays and quantitative analyses are made for the public b the Federal Government.Virtually all of the States maintain a bureau of mines, a geological survey, or some similar organization, frequently at the State University, where minerals found by residents of the State will be identified free of charge. Usually, a charge is made for assays. Specific tests, as on clays, are made by some of these offices.The Federal Bureau of Mines, although it attempts to avoid duplication of services rendered by State Bureaus, is always glad to give advice as to prospective markets. It does not compete with private assayers and chemists, but with respect to samples sent to its field laboratories, it does offer to identify them as far as this can be done by inspection and simple optical and chemical tests. This examination is usually sufficient to indicate whether the material has commercial value, or at least if the expense of an assay would be warranted. Except in connection with its own technical investigations, no assays or other special tests are made by the Bureau of Mines.The Federal Geological Survey and the National Museum also make simple tests of specimens as a public service. Neither of these bureaus nor the Bureau of Mines, however, can afford to render such services on long suites of specimens submitted by mineral dealers, well drillers, or others, when such work can be done regularly by commercial concerns."

Oct 1, 1949

By Kapila Pathirage, Michael S. Schultz, Gregory Sanders, Ulf G. Gwildis

Adequate understanding of the subsurface conditions along the alignment of a planned tunnel is key for managing project risk. For achieving this understanding, geotechnical borings are conducted during design. Where their spacing cannot reduce the risk of encountering differing site conditions (DSC) in-between borings to an acceptable level, supplemental exploration methodologies or data evaluation approaches may be required to bridge the data gap. This paper compares the exploration design approaches of recent tunnel boring machine (TBM) and microtunnel boring machine (MTBM) projects in the quaternary deposits along the Eastern Seaboard, the glacial geology of the Pacific Northwest, the sedimentary rocks of the South, and metamorphic rocks in western Germany, describing their respective effectiveness of managing DSC risk.

Dec 1, 2022

By Don Ibana

Supported by the Minerals Council of Australia (MCA) through the Minerals Tertiary Education Council (MTEC), three Australian universities–Curtin University, Murdoch University and the University of Queensland–have formed the Metallurgical Education Partnership (MEP) to jointly develop and deliver an engineering design capstone unit–Metallurgical Process and Plant Design–in their respective undergraduate programs in extractive metallurgy, in order to enhance the students’ educational experience. A unique feature of the program is the close interaction of the students in all three universities and a significant involvement of industry professionals. Now in its sixth year, it is clear that this unit is achieving its objectives

Jan 1, 2014

By C Tapia, B Hay

There is a close relationship between the mining industry, economic growth, and technological and social development. Mining activities benefit all economic agents, but only during a timespan determined by available reserves, primarily driven by internal factors such as production rate, technology and costs, and external factors such as prices determined by the market and taxes and royalties controlled by governments (Gordon and Tilton, 2008; Henckens, 2021; Tapia Cortez et al, 2018). The intense use of Mineral Commodities (MC) needed to maintain the current lifestyle has placed ore depletion as one of the main threats to sustainable economic, social and technological development. However, ore depletion does not only arise due to the finite nature of MC, price fluctuations or technological challenges. It is also triggered by the ‘economic limits of extraction’, determined by the optimisation of financial factors and technical restrictions within the regulatory framework (Henckens, 2021). Most reporting standards – if not all – define ore reserves as ‘the economically mineable part of a Measured and/or Indicated Mineral Resources’ determined by the technical and economic viability of extracting, processing and commercialising MC having the NPV as the fundamental decision – making tool (JORC, 2012; Krzemień et al, 2016). However, is the NVP an ‘economically’ basis index able to capture the complexity of economic phenomena? No, it is not, and it is crucial to define what is economic and financial. Although related, they are different disciplines. Economics studies the behaviour of the different market agents, including human behaviour and policies and explains the factors involved in the scarcity (or surplus) of goods and services. Finance focuses on financial systems and managing funds considering the time, cash available, and risk. It involves banks, loans, investments, and savings and can be considered a small subset of economics (Simon, 1959; Tapia Cortez et al, 2018). Given the economic nature of ore Reserves, endorsed by governments (Figure 1), NPV is an incomplete tool to determine ore Reserves as it limits the problem to simply maximising cash flows instead of optimising the economic benefits for all economic agents. In addition, using the rigid scheme of controlling taxation – unable to adapt to new market or economic conditions and systematically increasing – within the NPV framework only increases the sub-optimisation of ore reserves, mainly due to the systematic taxation rise. Short-term benefits of higher taxes and royalties are unlikely to offset the impacts of reducing exploration and project development in the long-term, which not only boosts ore depletion concerns but also reduces competitiveness, threatening economic and social welfare (Fisher, Cootner and Baily, 1972; Gordon, Bertram and Graedel, 2007; Lilford, 2017; Mardones, Silva and Martínez, 1985; Radetzki, 2009; Rodrik, 1982; Tan, 1987; World Bank, 2000). Holistic methods and collaborative tools, able to dynamically simulate and assess how changes in the technical settings, regulatory framework (taxes and royalties), and financial factors affect the availability of ore reserves and the impact for all economic agents, should be incorporated into the evaluation process to fill the gap.

Aug 2, 2023

By J. P. Powell

The application of secondary producing methods for recovering additional oil from known fields has been recognized for many years as important to the economy of the nation. One of the most successful secondary methods is waterflooding, which conserves our natural resources by preventing premature abandoment of stripper leases and revitalizing previously abandoned areas. Waterflooding as a secondary-recovery method was introduced into the Midcontinent region in 1931, and its use as such has become widespread. As with most new methods, the most favorable fields and leases received primary attention, whereas those with viscous oil or less favorable sand characteristics were bypassed. Numerous reports3 4 5 6/ have been published giving the results of individual waterflooding projects, In this report, attention is directed to the effect of a single factor, the viscosity of the oil produced,

Jan 1, 1959

By McHenry Mosier

This paper describing mining practice at Morenci, Ariz., is one of a series of articles on mining method, and practice in the various mining districts in the United States. At present (1929) practically all the mineral production in the Morenci district is from the Humboldt mine of the Morenci Branch, Phelps Dodge Corporation. The mining method used is adapted to the type of ore body being exploited; it has been developed by adopting methods used elsewhere and making necessary changes to fit local conditions. Improvements in current practices are still being made.

Jan 1, 1929

By J. J. Fallon

The subject is "Mergers, Acquisitions and Divestitures in Industrial Minerals, but my remarks could also be applied to new product development, resource development and other new business development activities. At the kernel of the subject is due diligence in major decision-making, that is, where major money amounts and a large corporate commitment are at stake. The "due diligence" means how carefully we do our homework before making the decision. The homework or feasibility study addresses different parts of the decision. In the industrial minerals business the study seeks to uncover the pros and cons in: o The mineral reserves, quantity, quality, mineability, access, etc. o The environmental impact of mining, processing and transporting. o The economics of operations. o Financial aspects o Legal aspects o Many other aspects o And -oh yes! the marketing aspects.

Jan 1, 1990

By L. Roux

The initial evaluation of a coal deposit often raises uncertainty with regard to the accuracy of the reported Resources and Reserves. Reconciliation of results from mining and beneficiation with the original raw field data highlights deficiencies in original estimations. Credible Resource and Reserve estimation forms the basis on which an entire mining enterprise is motivated, initiated, funded, and established as a commercially viable proposition. This is required for sustainable extraction purposes and to support vital downstream industries such as power generation. Accurate determination of the density of the matrix of the material being evaluated is the key to credible values being obtained for Resources and Reserves. Losses between 15% and 20% of the Resource/Reserve can be realized if incorrect densities are applied to the tonnage derivation. Coal plies and particles have different relative densities, determined by the maceral composition, rank, and mineral and moisture content. These factors in turn contribute to the moisture, volatile matter, ash and carbon contents of a coal, which affect the overall density of the raw coal. More specifically, the relationship of ash to density and the effective matrix porosity were found to be critical in solving the greater majority of the problems in predictive calculations. A major deficiency identified is the inability to determine effective porosity, allowing absorption of adventitious moisture and altering the mass of the core sample. Although the volume of the raw material is altered through crushing, the change in mass after controlled air-drying, used with the original geometrical volume of the raw material, provides a credible air-dry density and allows the determination of the volumetric change related to effective porosity. This parameter can be validated through the evaluation of proximate ash using the ash-adjusted algorithm and a correction for the inherent moisture applied to also give a credible relative density value for an air-dried sample. A combination of theoretical, empirical, and reconciliatory evaluations of the available data, taken from the exploration phase through the mining process to final production, has shown that an integrated approach using the ash-adjusted density (AAD) methodology, in conjunction with other evaluative techniques, provides credible results with a considerably higher degree of accuracy than is currently possible.

May 1, 2021

By P. Tracy

An advanced real-time monitoring system, called a "Tapblock Diagnostic System" is under development to help furnace operators manage the operation and maintenance of their tapblocks. The life of a water-cooled tap block in a smelting furnace ranges from several months to several years, depending on the operating conditions. Tapblocks are typically replaced at regular maintenance intervals; a strategy based largely on historical records and not on the actual condition of a particular tapblock. The Tapblock Diagnostic System monitors the tapblock throughout its life and accumulates probable wear events to help the operator assess the residual integrity of the tapblock. Benefits of this system include the ability to provide early warnings of tap block wear to provide improved safety and maintenance planning. Using cooling-water flow together with copper and water temperature measurements, the system performs calculations that compare the present tapblock performance with the expected operating envelope using a multivariate statistical method (Principle Component Analysis). The operating envelope is pre-calculated for a wide range of operating conditions using transient thermal modeling (Computational Fluid Dynamics). A state indicator in the form of a green, yellow and red light is used to inform operators of the tapblock performance and health status.

Jan 1, 2007

By Onwukamike, Onyedika G. O, Ogwuegbu M. O. C., K., Onyenehide C

A detailed mineralogical and elemental characterization of a lead (Pb) ore deposit from Ishiagu, Ebonyi State, Nigeria was carried out with XRD, SEM-EDX, and ICP-OES based mappingtechniques. The results show that the most dominant and valuable metal is lead (Pb = 95.02%, mass fraction). The main mineral is galena. Ilmenite and sphalerite occur as minors, which account for 2.71% and 0.80% respectively. Elements like Al, Ca, Mg, Ti, Na, Mn, Si and Sn occurred in trace amounts and are disseminated in the entire ore body.The surface and interrelations of the crystals were examined with x-ray mapping and the result shows the pattern of dissemination of the minerals within the ore body.

Jan 1, 2015

By B Morey, J Gordon, P Mackenzie

Mount Tom Price Mine is peerless amongst Rio Tinto iron ore resources around the world. It has provided Hamersley Iron with premium quality, high lump yield haematite ore over the last four decades. The Brockman type bedded ore, containing bands of haematite and shale of varying thicknesses has been traditionally bulk mined to either high-grade or low-grade based on alumina cut-off grades. As open pit mining has progressed deeper into the orebody approaching the keels of the megastructure, increased structural complexity, chemical and physical variations in the ore, unfavourable ore presentation and reduced blending options have become an issue for grade control and may have serious impacts on product stockpiles. The grade blocks and boundaries must be accurately defined according to geological contacts and where identified, selective mining may be applied. Therefore in-pit geological mapping is the definite and ultimate guide to achieve target grades and grade predictions. Under this scenario, it is absolutely vital that the mine geology team ensures this geological knowledge is passed onto the related departments including mining crews as well as to the short- and long-term planners.

Jan 1, 2002

By Jr. Chilson

This paper addresses the slurry pump industry as it exists today by touching on the business aspects, and by discussing research and development for material metallurgy and hydrodynamics for wear improvement which reduce operating and maintenance cost for the customer. It demonstrates why OEM parts give better value for cost.

Jan 1, 1996

By R. V. Ramani

Minerals, together with agricultural and forestry products, are the primary source of wealth produced in the United States. Although the production of minerals requires only a small fraction of the state's total land surface, as compared with either agriculture or forestry (Table 1), mining activities generally are much more disruptive to the land surface, and rehabilitation is more complex and costly. The past 10 to 15 years have witnessed a sharp increase in mineral exploration and mining, particularly coal mining, which has brought with it an increase in conflict over land use and an increase in negotiations for purposes of mineral prospecting and mining. The general increase in the production and consumption of coal and the particular increase in the percentage of coal extracted by surface mining methods coupled with a growing nationwide environmental consciousness have created increased public concern and in some cases outrage over mining activities. Although there is ample evidence to indicate that it is possible to plan for and design mining activities in such a way that they are compatible with other activities and can thus be made a part of a sequential land-use plan, there is a general lack of knowledge regarding the importance of mining as the provider of basic and essential raw materials to supply society's constantly expanding and increasing mineral needs. This lack of knowledge extends to such matters as land and mineral rights negotiations, the character of mineral deposits and minerals, mineral economics, and land-use planning.

Jan 1, 1977

By Kenneth H. Johnston

The Weber pool in Washington County, Okla. (fig. 1), covers an area extending from 2 miles east and slightly north of Bartlesville, Okla., to a point approximately 2-1P tiles northeast of Dewey, Okla. The pool is a part of the area designated by the Standing Committee on Oil Field Nomenclature, Kansas-Oklahoma Division, Mid-Continent Oil & Gas Association, as the Bartlesville-Dewey field. In the following discussion of the geology, development, and exploitation of the Weber pool, the writers, by means of structure maps, cross sections through various parts of the reservoir, and tabulated development data and production statistics, have recorded salient information on a field that was developed before .1910 in an Area that has been repressured since 1926. The total oil production to January 1, 19.0., from the 2,639 developed acres considered in this report, was approximately 14 million barrels, or a recovery of about 5,3;2 barrels per acre, or 227 barrels per acre-foot. The production of the estimated 18 million barrels of recoverable oil remaining in the Bartlesville sand reservoir will require the initiation of additional secondary-recovery practices on some of the leases and the application of a more systematic repressuring program on others.

Jan 1, 1950

By W. J. Schlitt, K. McNaughton

A heap-leach field test was conducted during the 1993-1994 winter season at Carmacks, Yukon Territory, Canada. The purpose of the test was to demonstrate the viability of heap leaching Carmacks oxide copper ore in an arctic setting on a year-round basis. The test itself utilized a 5-m-diam crib loaded with 250 t of composite ore from the Carmacks copper deposit. The ore was stacked to a total height of 7 m in the crib, including 1 m of ore as an over- layer above the emitter system. This matched the plan for the commercial heap at the time when the test was started. The design also replicated an interior segment of the commercial heap. Leaching was done at a flow rate of 0.2 L/min/m2 using leachate at 21 °C. This temperature was maintained with no external heat input other than normal process heat transferred from electrowinning to the leachate via solvent extraction. Winter conditions were quite typical of those expected at the mine site. The temperature reached -54°C, while averaging -13°C over a three-month period. In spite of some flow system problems, leaching continued unabated, and freezing was limited to the insulating ore over-layer and isolated points near the outer crib walls. Thus, the test demonstrated that year-round heap leaching of Carmacks copper ore is practical in an arctic setting.

Jan 1, 2000

The morphology of environmentally assisted cracks in stressed pipeline steel has been investigated, For a dilute and neutral solution (NS4) simulating ground water in contact with the steel, semi-elliptical cracks grow faster on the surface (2c) than in the depth (a), hence, the aspect ratio (a/c) decreases, This is explained using a deterministic concept since corrosion is dominant and the primary constraint is the conservation of charge, By contrast, when mechanistic conditions prevail, significant growth occurs in the depth, When underloads are imposed in the loading history, temporary accelerations in crack growth occur because corrosion rather than mechanical effects become dominant.

Jan 1, 2005

By S. Klingmann

ABSTRACT In this paper, we used data collected from the Gibraltar mine to analyze the effect of the TyreSense tire monitoring system on tire performance by reducing tire wear and preventing premature tire failure or damage. We analyzed the relationship between tire temperature, tire pressure, and tire failure or damage to help better understand the importance of controlling high tire temperature and pressure. The results enhance and expand the knowledge of the management of tire operational pressure and temperature.

Jan 1, 2014

By C Vejrazka

Northparkes is located 27 km north of the township of Parkes in central New South Wales, Australia. The operations consist of underground block cave mines and an ore processing plant that produces high-grade copper and gold concentrate. Production is currently sourced from the E48 Lift 1 block cave mine and open cut stockpiles. Mining commenced at Northparkes in 1994 as an open cut operation. Underground block cave mining began in 1997. Northparkes was the first mine in Australia to use the highly efficient block cave mining method, which relies on gravity and natural rock stresses to fragment the ore.The occurrence of air blasts is one of the principal mining hazards in block caving operations between the time of first undercutting and breakthrough of the cave to surface. As such, it needs to be managed continuously, and risk assessments need to be reviewed on a regular basis for applicability to changing conditions. Unfortunately, there is little literature on how to practically approach air blast risk assessments in a way that can be incorporated in the day-to-day operation of a mine. Previous methods of assessing air blast risk were tedious and results were often unrepeatable.With the extension of the E48 Lift 1 extraction level, it was necessary to assess the air blast risk for the extension drives and develop operational guidelines for production from the extension. A review of the methodology for assessing air blast risks revealed substantial improvement opportunities.This paper outlines the principles used for air blast risk assessments at Northparkes Mines and the methodology employed to achieve efficient, repeatable and auditable results.CITATION:Vejrazka, C, 2016. Northparkes Mines’ current air blast risk assessment practices for block caving operations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 257–264 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By John Blackshaw

NEW sources of supply of tungsten concentrates became necessary when the flow from the Far East was blocked in 1942. In Canada, one source has been noted in the workings of the Hollinger mine at Timmins, Ontario. For many years, a small amount of scheelite had been removed with the gold ore, and an appreciable tonnage of scheelite still remained in the mine. At the request of the Dominion Government, a plant was built to recover this scheelite in the form of a concentrate that could be used by the alloy-steel industry without further preparation. The plant began operating early in March, 1942, and a small tonnage of ore, carrying scheelite and gold values, has been treated daily since then. The possibility of recovering the scheelite had been considered on several previous occasions. Each time the proposal had been given up because the total profits from the enterprise were estimated to be insufficient to repay the capital cost of building the recovery plant. At the time the plant was built, additional information had been gathered about the tonnage and grade of the scheelite ore in the mine, and several thousand tons of ore grading higher than 0. 25 per cent WO3 (tungstic trioxide) were known to be available.

Jan 1, 1943