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By C. W. Davis

During the second year of its existence the Ore-Testing Section has actively prosecuted work in the standardization of testing methods, in conducting routine tests and analyses for other Government agencies, and in the determination of recommended processes for the treatment of representative ores from mining districts. Close cooperation has been maintained between the members and units of this Section and those of other Sections. J. A. Woolf and J, B. Clemmer have continued to act in an advisory capacity and. R. E. Head has contributed valuable assistance in the microscopic examination of ores and metallurgical products that did not respond readily to standard treatment methods.

Jan 1, 1938

By Leo Panian

Over the last decade, drilled and post-grouted micropile foundations have come to be increasingly relied upon for resisting seismic loads in building foundations on the West Coast. Micropiles have been successfully deployed in a range of soil conditions, in vertical as well as battered configurations, to support a variety of structural systems difficult soils. Their high load capacity in tension as well as in compression, their ability to be installed in confined spaces with minimal overhead clearance, and their ability to be directly tested in an installation have made them indispensable for seismic strengthening of existing structures. More recently, growing industry experience along with improvements in design guidelines have led to wider acceptance of micropiles among engineers and building officials. The increasing availability of the specialized materials, coupled with growing familiarity with drilling technologies among design-build contractors has made micropiles more cost-effective and competitive. For the first time, micropiles are finding applications in the construction of new buildings, where they are combined with shallow footings in hybrid foundations to efficiently resist seismic loads. These new applications rely on more intensive engineering analyses to evaluate the performance of micropile foundation systems and develop detailed requirements for design and construction. This paper describes the design approaches and the analytical methods for the seismic design of hybrid micropile foundations, and provides examples of recent construction projects that demonstrate the application.

Jan 1, 2010

By T. R. Rehak

Blasting operations are an essential element in the recovery of our Nation?s mineral resources. The mining industry uses billions of pounds of explosives annually. The majority of blasting occurs in surface mining operations. Blasting results in the fragmentation and often the projection of rocks. Frequently, the rocks are thrown beyond the expected limits. Flyrock and failure to secure the blasting area dominate blasting-related accidents in mining, especially in surface mining. Blasting accidents in the mining industry tend to result in critical injuries or fatalities. Accident reports and information collected from the Mine Safety and Health Administration (MSHA) and other government agencies provide supporting evidence. According to the data collected, blasting-related accidents (in mining) were 11 times more severe than all other types of mining accidents. Blasting accidents are not unique to mining operations - the same situation exists in the construction field. In this paper the authors have compiled a list of the primary causes of flyrock and the failure to secure the blast area. In the next phase of this project, typical blasting scenarios will be reviewed which will highlight the main reasons flyrock and/or lack of blast area security occur. This will alert miners and construction workers to the current problems/hazards associated with blasting and to identify other safety measures to protect personnel.

Jan 1, 2000

By LeRoy R. Curwick

This Bureau of Mines report presents the results of a study conducted to assess the domestic availability of chromium from superalloy and cast heat- and corrosion-resistant alloy scrap material. Six alloy classes included in this survey were investment cast, hardfacing, and wrought nickel- and cobalt-base alloys, wrought nickel-iron-base alloys, and heat- and corrosion-resistant alloy castings. Data were collected for 1976 on metallic scrap generation, use patterns, and production practices for these alloy producing and using industries. A model was developed that allowed an assessment of the materials flow circuits within the industries that produce these alloys. The types, amounts, sources, secondary products, and ultimate destinations of chromium- containing metallic scrap for the six alloy classes were determined. Regarding the overall recycling efficiency of these alloy producing and using industries, of the 580.9 million pounds of scrap generated from these six alloy classes in 1976, about 72 percent (416.8 million pounds) was remelted by the same alloy-producing industries, about 18 percent (104.9 million pounds) was downgraded into stainless and low-alloy steels, about 3 percent (19.7 million pounds) was exported, and about 7 percent (39.5 million pounds) was lost through landfill or other disposal or service wastage. The lost material is primarily contaminated oxides for which recovery is currently uneconomic. However, the 124.6 million pounds of scrap material downgraded or exported in 197b contained potentially recoverable critical strategic elements. The amount of scrap material lost to the six alloy-producing industries in this manner contained 22.1 million pounds of chromium, 53.4 million pounds of nickel, 5.9 million pounds of cobalt, 35.9 million pounds of iron, and 7.3 million pounds of other alloying elements.

Jan 1, 1980

By C. I. Garcia, G. Zhou, W. Gao, A. J. DeArdo

The development of X-100 and X-120 linepipe steels was investigated using a series of low-carbon Mo-Nb-B steels. The laboratory steels were vacuum melted and processed using advanced thermomechanical processing (TMP) philosophies. Prior to the laboratory hot-rolling experiments, the grain coarsening temperature, the conventional T95 and T5 start-stop recrystallization temperatures and the transformation behavior of y were studied using a computer-controlled high temperature deformation MTS-458 and a Theta-IV High Speed dilatometer systems. The results from these experiments provided the guidelines for the design of the laboratory hot-rolling TMP processing experiments. The mechanical properties of the experimental steels showed yield strengths in the range 700-850 MPa and CVN impact properties of over 80 J at -20°C. The best balance of mechanical properties was obtained by using CCR+DQ+Tempering treatments. The major microstructural features responsible for the observed mechanical properties in order of importance were: a) substructural refinement associated with lower bainite, b) dislocation strengthening, c) fine recrystallized ferrite, and d) small amounts of retained austenite. Fine Nb(C,N) precipitates formed in ferrite were observed, however their contribution to the strength was minimum. Most of the Nb(C,N) precipitation took place in austenite. This precipitation was used to exert microstructural control of austenite during hot rolling. The physical metallurgy and optimum TMP to achieve the mechanical properties are detailed in this paper.

Jan 1, 2005

By Ramon Augusto Moretti, Henrique da Rocha Severino, Renato Nascimento de Castro, Fernando Cesar Sousa

Rolling stand 12 (LTx) of long steel, installed in the company A, Piracicaba - SP unit, had presented high levels of vibration, which affected its internal components, such as: shaft, gears and bearings, generating downtime. To evaluate this equipment a study was proposed by the following engineering techniques: Conventional Vibration Analysis, Operational Deflection Shape (ODS) and numerical simulation by the Finite Element Method (FEM). In the Conventional Vibration Analysis, high levels of vibration were observed during manufacturing process, especially when the material reaches the equipment. Impacts generate high values in acceleration, on average 80 m/s² peak to peak. In the moment of impact, misalignment of internal components was observed by ODS. Field results were correlated to those obtained by the Finite Element Method, which allowed to calibrate FEM model. Thus, the most effective structural modification already numerically evaluated was implemented in the system. Afterwards, new measurements by vibration and ODS techniques were performed, and attenuation of vibrational levels and operational mode, which overloaded the internal components rolling stand, were verified.

Oct 1, 2019

By Robert H. Townsend

The following paper discusses the mining, transportation, and crushing methods, with costs, at the San Andreas plant of the Calaveras Cement Co. It is one of a series, prepared for and published by the U. S. Bureau of Mine describing methods used in cement-rock quarries throughout the country. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total cost. It is recognized that publication of total costs mightin some instances cause embarrassment to individual producers as well as to the industry as a hole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost-tabulations shall ensue.

Jan 1, 1933

By V. P. Keran

The lead and copper smelting processes employed by Mount Isa Mines Limited, Mount Isa, Australia, are used to illustrate an operating viewpoint of some problems and solutions encountered in existing commercial sulphide smelters. The smelting processes discussed; include updraught sintering, blast furnace and reverberatory smelting, and converting. Selected examples are given of methods implemented, and options available, to improve the productivity and efficiency of conventional smelting processes.

Jan 1, 1983

"Investment in diamond exploration has been declining over the past decade, in spite of positive long-term industry fundamentals and a growing interest in diamonds as an investment category. The lack of new significant discoveries in recent years has eroded investor confidence, yet no new discoveries are possible without investment in exploration. Junior ‘mine finders’ have been the hardest hit. Their agility, tenacity, and appetite for risk are not sufficient to attract the funding required, even at the greenfield stage. Developing new discoveries into mineral resources can be crippling without solid financial support. Junior incubators could play a crucial role, especially at the project evaluation stage – but where are they? Alternatives to traditional funding mechanisms have become available, many still untested in the junior diamond exploration space. Valuable lessons can be drawn from the past and used to inform emerging new strategies. IntroductionDiamonds are the ultimate expression of love. Their ancient and timeless allure continues to influence consumer emotions and behaviours across continents, cultures and age groups. Analysts are predicting a sustained supplydemand shortfall in the years ahead which will trend diamond prices generally upwards. With positive long-term industry fundamentals, one cannot help but wonder why funding for diamond exploration and development projects is so scarce.Investment in exploration across commodities – including diamonds – has been declining for a number of years, reaching a historic eleven-year low early in 2017. The lack of major diamond discoveries in recent years has done little to strengthen the case for investing in diamond projects, yet no new discoveries can be made without investment in exploration.Global estimates of known carats in the ground stand currently at 2.5 billion carats, which equates to around 18 years of production at current levels of 140 million carats (mct) per annum. Sustainable replenishment of depleting diamond resources is possible only through the development of new discoveries. This is what junior explorers are best at – but they need investors to fund their evaluation activities from early in the project development continuum."

Feb 1, 2019

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 J. van Deventer

Ion exchange is widely used in hydrometallurgical operations for the recovery and purification of valuable metals. Special chelating resins have a high affinity for specific elements, allowing the selective removal of low levels of impurities from a background of highly concentrated valuable metal. Solvent-impregnated resins have been added to this group more recently, expanding the treatment options. These products find application in the purification of cobalt-rich liquor prior to the production of high-purity metal or metal salts. Impurities in copper-cobalt circuits that are typically targeted by ion exchange include iron, uranium, copper, zinc, nickel, bismuth, and antimony. Ion-exchange resins can also be used to treat tailings, thereby recovering additional valuable metal and improving the Environmental and Social Governance credentials of the operation. This article takes a look at various applications of ion exchange in copper-cobalt operations

Jan 1, 2023

By Bernard Lewis

This report summarizes fundamental research and technical studies conducted by the Explosives and Physical Sciences Division of the Bureau of Mines from July 1, 1949, to June 30, 1950. It is the fourteenth of a series of annual reports whose aim has been to bring to the reader a résumé of the research results that have appeared in published form during each fiscal year under the authorship of members of the staff. These are referred to throughout the report.

Jan 1, 1951

By R. R. Sayers

THE South African Mining and Engineering Journal recently pointed out that no satisfactory solution of the question of compensation for silicosis can be arrived at by placing further liability of an inequitable nature upon the mines. There are at present 35 scheduled mines liable to contribute to the annual levy of $800,000 and provide for the net outstanding liability of $6,400,000. Several of these mines have, as yet, not been able to set aside sufficient funds against their out- standing liability to the Compensation Fund. The gold producers declare that the gold mining industry today is passing its zenith, and that the production of gold will decline, with a consequent lessening of the spending power of the mines, which in about ten years will be reduced to a great extent unless encouragement is given for the opening of new mines. It is during this period of decline that the mines will be required to meet the large burden already created by miners' phthisis. In England the Workmen's Compensation Act, 1925, was extended to industries involving exposure to asbestos dust.

Jan 1, 1931

By K. E. Stanfield

Asphalts from. Wyoming "black oils" are being studied at the Petroleum Experiment Station of the Bureau of Mines at Laramie, Wyo., in cooperation with the University of Wyoming. These black oils are characterized by their high-asphalt, high-sulphur, and low-gasoline content and are difficult to refine by present methods into high-octane motor fuels, burning oils, and lubricants. Accordingly, their principal use, at present, is for the manufacture of road oil and asphalt. The present production of black oil could be increased to meet a greater demand. During 1937 the daily production of these crude oils in Wyoming was slightly over 13,000 barrels, while the estimated potential production from existing wells was 56,000 barrels.

Jan 1, 1939

By Howard H. Fields

Any mining engineer with a desire to operate independently, with some financial backing, and with no fear of heavy responsibility and long hours, should be able to make a comfortable living in Mexico. Barring a few inconveniences such as a lack of satisfactory liability or accident insurance, the difficulty of obtaining repair parts or vehicles, and the length of time required to receive returns from shipments, the operation of small mine is not at all difficult. It is, in fact, a little easier to find a good prospect in Mexico than in the U.S.

Jan 1, 1950

The U.S. Bureau of Mines Information and Analysis Directorate collects worldwide data on virtually every commercially important nonfuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U.S. economy. The Bureau's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority for the U.S. Bureau of Mines survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96-479, 96th Congress). This act strengthens protection for proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1993

By G. A. Bezuidenhout, J. Davis, S. Lefume, J. P. T. Kapusta, D. K. Chibwe

"Although the centennial of the Peirce-Smith (PS) converting process has recently been celebrated, the technology has essentially not changed much since its inception. PS converting is used extensively in the Cu, Ni and PGM industry to remove iron and sulphur from a molten matte phase. A typical PS converting process would use low pressure air supplied by a blower to bubble air through the molten bath. This bubbling injection regime is inherently inefficient from a process and energy consideration. In the late 70’s and early 80’s, Brimacombe and co-workers demonstrated at both laboratory and plant scales that sonic injection (jetting regime) into copper or nickel converters could reduce or eliminate the above hindrances characteristic of PS converting. Since then, in spite of these successes, very little industrial applications have made headway in the converting process of non-ferrous metal mattes on a commercial scale. As part of its operational improvement and energy reduction program (process efficiency), Lonmin Platinum decided to conduct a full scale industrial evaluation of sonic injection using air only to establish if punchless, high efficiency sonic injection was feasible in its small 3.05 × 4.57 m converters (10’ × 15’). A plant trial was run for four weeks in one of its three converters. This paper discusses the plant demonstration with a focus on the experience acquired by Lonmin together with the key learnings from the trials. Reference will also be made to the commercial aspects of a full scale implementation of sonic injection in all three converters in the smelter. INTRODUCTION AND OBJECTIVESAlthough the centennial of the Peirce-Smith (PS) converting process has recently been celebrated (Peirce and Smith, 1909; Southwick, 2009), the technology has essentially not changed much since its inception. PS converting is used extensively in the Cu, Ni and PGM industry to remove iron and sulphur from a molten matte phase. A typical PS converting process would use low pressure air supplied by a blower to bubble air through the molten bath. This bubbling injection regime is inherently inefficient from a process and energy consideration."

Jan 1, 2012

By Madan M. Singh

This report presents the results of an investigation of inclined roof bolts, anchored over pillars, in room-and-pillar coal mines susceptible to shear failures of the roof. Although the field data do not support this contention, it is believed on the basis of analyses and other work that inclined roof bolts do offer potential under some circumstances.

Jan 1, 1978

By Van H. Manning

Chemical and physical tests of coals for the use of the Government have been made by the United States Bureau of Mines. These tests form part of a general study of the coals in the United States with respect to the manner in which each coal can be utilized most efficiently. As a result of this study, much information of value to all industries using coal has been compiled. Special investigations by the Bureau of Mines of the fuels used by the Government have, until recently, been for the most part limited to coal. In the course of these investigations the bureau has de- veloped new methods for use in the purchase of coal by the Gov- ernment. The application of these methods permits an intelligent selection of the coal adapted to the requirements of particular heat- ing or power plants, and has already resulted in the saving of large sums of money. In addition, these investigations have led to the compiling of a series of carefully made analyses of samples of coal collected in a predetermined manner in the mines of all the impor- tant coal fields in the United States, and these analyses are being published to enable Government purchasing agents and all users of coal to select the coal best suited to their needs. The purpose of this paper is to describe briefly the general char- acter and commercial quality of some of the coals mined in the United States that reach tidewater shipping ports, and to show in a general way the important characteristics of those coals that by reason of transportation facilities and the situation of the coal fields are most available for export. Coals of excellent physical character and of high heating value are available for export. For this reason and because of the modern facilities at the collieries for properly grading large shipments, American producers can supply coals suitable for any kind of service. The transportation system from the mines to tidewater and the coal- handling equipment for loading boats at the various ports are highly developed, so that producers are able to give excellent service to foreign buyers. Enormous quantities of these coals have been used by railroads, manufacturing, illuminating-gas, and coke plants, and seagoing vessels, and for household purposes. Much of the coal available for export is superior to the coals that have been supplied to foreign users from other sources.

Jan 1, 1916

By C. Garcia, J. J. Opazo, A. Potulsha, T. Comi

"Sierra Gorda SCM is a joint venture partnership of KGHM International (owned by KGHM SA, Poland), Sumitomo Metal Mining and Sumitomo Corp. (Japan) operating in northern Chile. The Sierra Gorda openpit mine and coppermolybdenum processing plant will become one of the largest mines in the world. The need for optimum production efficiency and sustainability has driven the creation of the most modern, wellinstrumented mine in Chile. This article contains a general review of the project including geology and history.This was a fast-track project going from greenfield site acquisition to mill startup in 10 years. Highly experienced and motivated engineers and technical staff have overcome many significant challenges resulting in a rapid ramp-up of production capacity. A potential expansion to double the production rate in the fourth year of operation has also been intensely studied.The Sierra Gorda property is located in the Atacama Desert of northern Chile, in the District of Sierra Gorda, Region II of Antofagasta, Chile (Fig. 1). There is almost no precipitation in this area. The mine site is generally flat with some rolling hills. The project is located about 5 km (3 miles) from the village of Sierra Gorda at an elevation of approximately 1,700 m (5,600 ft) above mean sea level. The village is near a highway and railway line. The city of Calama, home of the famous Chuquicamata Mine, is located about 60 km (37 miles) northeast of Sierra Gorda. In addition, the SG mine is in the midst of numerous other mines including Spence, Esperanza, Mantos Blancos, El Tesoro, Lomas Bayas, Gabriela Mistral, El Abra, Radomiro Tomic and Escondida, to name a few.The primary organizational value at Sierra Gorda is "Zero Harm." This includes employees, contractors, the environment, the community, plant facilities and mine equipment. A cornerstone of this program is called 5X5S (five by five S), which combines the lean principles of 5S with the safety model of taking five steps back and thinking about the task at hand for five seconds, five minutes, the time it takes to assess and manage the risk. "People caring about people" promotes proactive engagement in the safety of coworkers and others at work and at home."

Jan 1, 2014