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By d&apos, Kathleen J. Amico

This summary appears in Minerals Year-book volumes I and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1966

By L. Mpolokeng, J. P. Labuschagne, H. Yilmaz

"An investigation into pillar cutting was carried out at a platinum mine on the western limb of the Bushveld Complex. The focus was on crush pillar design and implementation in order to ultimately improve the compliance percentage for pillar cutting. The major findings from the investigation suggest that the pillar cutting problem lies with the implementation of the design rather than the design itself. Observations of the practical issues underground that prevent good pillar cutting were made. After these issues had been identified, recommendations to rectify these problems and a few other issues identified during the investigation were provided. The recommendations are aimed at improving the pillar cutting compliance and reducing the likelihood of pillar bursts or pillar runs, which will ultimately create a safer mining environment. Paper written on project work carried out in partial fulfilment of BSc. Eng. (Mining Engineering)"

Jan 1, 2015

By John C. Machisak

INJURY EXPERIENCE AND EMPLOYMENT DATA on all stone quarries and associated plants in the United States are presented in this publication for the calendar year 1959. Such related operations as the manufacture of cement and lime and rock dressing are included. Data on clay and sand and gravel operations are not included and will be found in other Bureau publications on injuries and employment. The Bureau is authorized to make requests for such data and the information voluntarily submitted by the operators contributes to the promotion of safety in the quarrying industry. Every effort has been made to make this canvass as complete as possible. Data for production workers and office employees at the quarry site are included.

Jan 1, 1963

By John C. Machisak

INJURY EXPERIENCE AND EMPLOYMENT DATA on all stone quarries and associated plants in the United States are presented in this publication for the calendar year 1959. Such related operations as the manufacture of cement and lime and rock dressing are included. Data on clay and sand and gravel operations are not included and will be found in other Bureau publications on injuries and employment. The Bureau is authorized to make requests for such data and the information voluntarily submitted by the operators contributes to the promotion of safety in the quarrying industry. Every effort has been made to make this canvass as complete as possible. Data for production workers and office employees at the quarry site are included.

Jan 1, 1963

By V. A. Cammarota

In this report, the effects of anode-production variables, such as aggregate coke sizes, pitch binder content, and baking cycle, were investigated. A small alumina reduction cell proved effective in evaluating anodes prepared from commercial materials and from lignite coke and pitch. Compressive strength was found to be the physical property most significantly influenced, but it did not appear to affect anode consumption. Specific carbon consumption, that is, the ratio of carbon in the anodic gas to carbon theoretically oxidized at the anode, was used as an index of anode consumption. It was found that an anode made with lignite coke and commercial pitch was very low in consumption; however, anodes made completely from lignite but by a different fabrication method showed high consumption and anode deterioration. Microscopic examination of anodes after electrolysis showed evidence of higher consumption at low current densities, and was useful in judging overall anode quality. Based on the physical properties of the anodes and their consumption during electrolysis, lignite can be a suitable material for anodes, provided the proper fabrication conditions are used.

Jan 1, 1970

By Raymond W. Hiteshue

Experiments were conducted al temperatures of 480° to 800° C. and hydrogen pressure of 6,000 p.s.i.g. to determine the effect of coal residence time on the conversion of a high-volatile bituminous C coal to liquid and gaseous products when using a semicontinuous apparatus designed fur rapid heating and cooling of reactants. The objective of the studies at high temperatures was to determine if appreciable quantities of coal could be converted to gaseous hydrocarbons and low-boiling liquid hydrocarbons. Experiments at lower temperatures were designed to indicate shifts in product distribution with respect to temperature and to learn more about the general mechanism of the reaction when using close control of coal residence time. One percent molybdenum, based on m.a.f. (moisture-and ash-free) coal, was used throughout this investigation. At 800° C., 6,000 p.s.i.g., and "zero" residence time) the yield of gaseous hydrocarbons was about 38 percent and the yield of oil about 4.5 percent, based on m.a.f. coal. With IS minutes residence time, under the same conditions, the yield of gaseous hydrocarbons was approximately 80 percent with no increase in yield of oil. Apparently at 800° C., and hydrogen pressure of 6,000 p.s.i.g. coal was rapidly carbonized to char with expulsion of volatiles. Char was then slowly hydrogenated to gaseous hydrocarbons without production of oil.

Jan 1, 1962

By B. Spigarelli

Carbon dioxide sequestration by conversion to carbonates has become a promising option for CO2 storage. Experiments were conducted to determine the feasibility of CO2 sequestration at ambient conditions using a Ca-rich industrial waste in a carbonate solution. The Ca-rich industrial waste used in this study was lignite fly ash. Fly ash was chosen because it is cheap, available near large CO2 point sources, already in powder form, and reactive due to amorphous properties. In the experimental set-up, CO2 absorption was inferred by monitoring feed and exhaust gas CO2 concentrations. The addition of an alkali to a fly ash-distilled water solution provided a 50% increase in CO2 absorption of the solution. Absorption time also increased by 50% compared to a fly ash-distilled water solution. TGA analysis was used to determine the extent of CO2 sequestration in the carbonate form. At a liquid to solid ratio of 20:1, the conversion of ?free? calcium to carbonates was 75%. A CO2 balance on the system concluded that at the current operating conditions 42% of the total CO2 fed to the system was sequestered in the carbonate form. SEM-EDS analysis of the fly ash particles before and after reaction with CO2 indicated that the carbonate compound being formed was calcium carbonate. The analysis identified rhomboidal structures on the surface of the fly ash particles after reaction with CO2, but not before. These rhomboids are characteristic of calcium carbonate formation and they had higher Ca, C, and O concentrations than the host spheres, suggesting calcium carbonate formation.

Jan 1, 2012

By J. K. Lemley

The human element in large measure dictates success in contracting relationships. Because of our professional backgrounds, we view contracts primarily as either engineers, contractors or owners. A beneficial contractual environment--one in which decisions, risks and benefits are shared--demands equal consideration of all three points of view. Most of the older cities in the United States, for example, suffer from bad contracts--generalized, patched-together documents that represent an accumulation of modifications originally written to compensate for specific situations that have occurred over the years. Because such documents lack coherence, they often present conflicting instructions which lead to defensive, ultimately destructive attitudes among the parties involved in the day-to-day administration of the project. Good contract development begins with a strong central philosophy to which the details of the contract can be related. First, the owner should establish a comprehensive philosophy in which risks between the parties are identified. Following this, a specific contract document can be written to satisfy this established philosophy. The contrast between two opposed contractual situations, NYC Water Tunnel Number Three and the Seabrook Nuclear Power Plant Cooling Water Tunnels, illustrates how comprehensive, well-written contracts--contracts which share both risks and benefits--provide the basis for achieving quality construction that will reward engineer, contractor and owner.

Jan 1, 1983

By D. J. Dollhopf

This research was part of an effort to investigate means of reestablishing non¬polluted hydrological systems in areas where surface mining directly impacts shallow ground-water resources. Chemically undesirable overburden material was selectively backfilled with the intent that it would be below the future root zone, be above the reestablished aquifer, and would not be leached as a result of deep percolation. After 2 years the buried material remains above the spoil aquifer and below the maximum rooting depth. Unsaturated water flow from the land surface to the buried material occurred during wet climatological periods. No significant leaching of buried material was observed, however. Overburden sample contamination from drill stem joint grease with Pb, Zn, and Cu additives caused substantial error regarding DTPA extractable trace metals. A grease with teflon and talc additives was recommended for use in future sampling programs. DTPA extractable trace elements in overburden material had no statistical relationship to post-mine ground-water quality. Overburden columns leached with water produced leachates comparable to overburden and spoil ground-water trace metal quality. A depositional model described the Rosebud Coal overburden as a fluvial system with distinct units of sand, silt, and clay, with distinct chemical properties. Physical and chemical characteristics of the model were comparable to the in situ geochemical system, a relationship which may aid in locating overburden materials unsuitable for reclamation.

Jan 1, 1979

By Theresa M. Bodus

The strength of roof shales is, in part, a function of the preferred orientation of clay minerals within them. Therefore, analysis of clay fabric under both air-dried and hydrated conditions should be helpful in understanding roof shale failure. Core samples were collected from the Energy, Anna, and Lawson shales, which are locally present as roof shales of the Herrin No. 6 coal of southern Illinois. The Clay Fabric Index (CFI) was measured for thirty core samples, using X-ray diffractomtry, to investigate the relationship between clay fabric and roof collapse in coal mines. Greater CFI values indicate a weaker preferred orientation among clay minerals, which generally results in a weaker inter-grain bond. Average CFI values for air-dried samples were: 0.15 for Anna shale; 0.20 for Energy shale; and 0.37 for Lawson shale, .After the introduction of water, average CFI values increased to: 0.28 for Anna shale; 0.22 for Energy shale; and 0.43 for Lawson shale. The laboratory results indicate the following: [l] under air-dried conditions, Anna shale is the most stable, followed by Energy and Lawson shales; and 121 under hydrous (mine) conditions, Energy shale is the most stable, followed by Anna and Lawson shales. In mine environments where roof failures involving Energy shale have occurred, planar trends delineated by a relatively high density of small (0.2-4 cm diameter) iron concretions have been reported along the failure surface. Radial cracks have been observed around unsealed anchor bolt holes in the Anna shale. Instability of the Lawson shale is ubiquitous in coal mines. In the laboratory, similar physical changes were noted in the shale samples after the introduction of water, including [l] increased hydration around the perimeter of iron concretions in Energy shale, [2] radial extension cracks in Anna shale, and 131 extreme slaking of Lawson shale. Measured increases in the CFI reflect the observed physical changes of the samples upon the introduction of water, which probably reflect changes in strength that may result in roof failures in hydrated mine environments.

Jan 1, 1989

By N. W. Byrne

THE study of diamond drill results at the Lake Athabaska property of Athona Mines, Limited, and the co-ordination of information secured, has demanded extensive application of methods for interpreting true conditions, both structurally and from the point of view of ore outlook. This work was in charge of a capable engineer, who, as the result of exhaustive study of the drill cores, has been able to issue maps and plans exceeding the expectations of the majority of engineers and geologists who visited the field during the past summer (1935); that is, having in view the fact that staking of the property had been completed but a few months beforehand and that geological conditions were practically unknown up to the time drilling began in April. The following pages present an outline of the work of the assay and engineering offices in co-ordinating and interpreting the results of the drilling. The writer desires to acknowledge the suggestions offered by A.P. Beavan, geologist and engineer at Athona Mines, whom he assisted during the drilling campaign, and also the co-operation of the drilling contractor's employees. The geological map, mine plans, and forms accompanying the paper are from the Company's engineering office files.

Jan 1, 1937

By Robert S. Sanford, Harold C. Pierce

"At one time the Alaskan Eskimo lived in many small settlements scattered along the Arctic coast. These settlements extended as far south as Bristol Bay and several miles inland on the large rivers. When the white man established trading posts, schools, hospitals, and missions, these people gradually congregated around them in a few large villages. The natural fuel supply near many of the large villages along the Arctic coast became exhausted as a result of the abnormally large influx of people from small outlying settlements.The population of Barrow, Alaska, according to the 1940 census, is 363 persons, but since that time it has increased considerably, and later estimates place the present population between 400 and 500 persons. With the exception of 25 white persons, the entire population is comprised of Eskimos.The government maintains a school, hospital, radio station, and weather station at Barrow. In addition to the government, installations, there is a church, a privately owned trading post, and cooperative store owned by the Eskimos.For many years the Barrow Eskimos depended on driftwood and petroleum residue from Cape Simpson for their fuel supply. This fuel provided not only warmth for the Eskimo during the long cold winters but also heat for melting ice, the only source of 'water during .the winter. In recent years the sources of petroleum residue and driftwood have not been adequate to meet the demands for fuel During the winter of 1942-43 and again in 1943-44, Barrow experienced an acute shortage of fuel.The fuel problem at Barrow was brought to the attention of Governor Ernest E. Gruening, who was instrumental in getting a Bureau of Mines engineer4/ to investigate reported coal occurrences in the vicinity. Coal deposits along the Meade River and at Peard Bay were examined during the spring and fall of 1943. The Alaska Native Service shipped in mining equipment in September 1943 and commenced stripping an open-pit mine on the Meade River in June 1944. In conjunction with this work, an engineer5/ of the Bureau explored by churn drilling to determine the tonnage of- coal in the vicinity of the mine. In addition to this work, the Bureau of mines examined coal deposits in Peard Bay area and along the Kuk River south of Wainwright."

Nov 1, 1924

By Marcel Vallée

Frequently, costs overruns and defaults in mining project performance result in serious problems and headaches for all project participants and impact on corporate objectives, profits and image and, occasionally, lead to project failure. As mining professional s, we should be very concerned that, in a recent World Bank paper (Weber-Fahr, 2001), geological and technical risks were considered the most important ones facing mining projects. Whenever we manage to reduce or minimize these risks, we are in better position to overcome the environment-, market-, finance- and community-related ones. The causes of this situation seem rather systemic, as a fairly long list of industry problems with new pro jects has been described in industry papers in pas t and recent years. A brief review of industry problems with mining projects will be given first, followed by a review of the basics of the current Quality Management and Continuous Improvement perspectives that have evolved from earlier quality control and quality assurance systems and policies. Particular particular attention will be given to the work of W. E. Deming. As the system approach is an essential part of such policies, it will be described succinctly. Given that poor communications and interactions among geologists, mineral processors and mining engineers/operators ca n seriously affect project efficiency and profitability, these interrelated processes with in the mining systems will be analyzed and modelled and the impacts of such situations will be described through a number of anonymous case histories and examples. A synthesis of Dr Deming's management system, includ ing his Four teen P oints and System of Profound Knowledge, will be prese nted .

May 1, 2002

By James C. Fowler

The design and field testing of a seismic miner detection and location system arc described. This work was carried out over a period of three years. The first two and one-half years were sponsored by Continental Oil Company, while the last period of tests were done as the first part of a one-year contract with the U.S. Bureau of Mines. Laboratory and field experimentation in three different nines under simulated emergency conditions have led to three important results: (1) Taps on roof bolts with normally available objects can usually be detected up to horizontal distances of 1,000 ft. (2) The origin of the tans can be located by on-site processing with a small computer. (3) Some predetermination of the approximate location is necessary for a quick and successful rescue. This report also includes preliminary specifications an,d cost guidelines for construction of a transportable field system capable of matching the performance characteristics of the one used during the field tests.

Jan 1, 1973

By V. H. Gottschalk

Among the procedures developed by the Germans for providing the tonnage of iron powder needed to make rotating bands for artillery shells is the use of a ceramic tunnel kiln, not only for finishing the reduction of centrifugal powders but also for making so-called "brickyard sponge iron," which, after crushing and grinding, seems to yield a product suitable for powder-metallur- gical purposes. The final report issued jointly by the German Powder-Metallurgical Society (DPG) and the Chemical-Metallurgical Branch of the Research Depart- ment of the Metallgesellschaft, Inc. (ZFC of MG) gives the available details of this procedure, which may be regarded as a further development of the process in commercial use since 1911 at a ceramic plant in Hoeganaes, Sweden. The Bureau of Mines' wartime development of the Hoeganaes process also cul- minated in the adaptation of ceramic tunnel kilns for carrying out the solid- carbon reduction of iron ores, and comparison with the German technique should further advance the art. This information circular is issued as a supplement to Bureau of Mines reports of investigations Nos. 3819,2 3822, 3841,2 and 4271, on brick- yard sponge iron and is based on four German reports entitled "Making Iron. Powder in the Tunnel Kiln," translated from FIAT microfilm reel H-46, frames 9190-9209, 9280-9299, 9339-9357, and 9377-9384 (PB L 70042), which represent the four original research reports, Nos. 2005, 2008, 2010, and 2012, respec- tively, of the Metallgesellschaft, Inc.

Aug 1, 1948

By Donald L. Brothers

"OUT IN BRITISH COLUMBIA, we have a legendary creature called ""The Sasquatch,"" a large ape-like creature which, according to those who claim to have seen it, somewhat resembles the Abominable Snowman of the Himalayas. Through the years, the legend bas been perpetuated by hunters and prospectors who return from remote wilderness areas with fantastic tales about hairy creatures, twice the height of an average human being, who leave 2-ft-long footprints in the soft forest floor. However, the existence of this creature bas never been proven and the attitude in British Columbia circles is that the whole thing constitutes either a great discovery or a giant hoax, and is about equally unbelievable either way.The Sasquatch, however, is not the only giant in British Columbia. If you find the Sasquatch story un-believable, you'll fi nd it just as hard to believe what is happening in the mining industry out west. We have opened four new mines so far this year (1967), another mine is expected to be brought into production before the end of the year and any mining man will tell you it's just the start of a mining boom which will continue for many years if metal prices are maintained and the federal government sees fit to discard the taxation changes pro-posed in the Carter Royal Commission Report regarding mining."

Jan 1, 1968

By B Cope, Y Churi

Roxgold was a small exploration company when it discovered the Zone 55 orebody at the Yaramoko project in Burkina Faso in 2010. Since this time, it has actively progressed the project with the completion of a preliminary economic assessment in 2013, a feasibility study in early 2014 and obtained full permitting for construction in January 2015. With no other underground gold mine in Burkina Faso, developing a modern and productive modern gold mine in West Africa was considered a significant challenge as Roxgold moved from explorer to producer.To facilitate this development, Roxgold engaged an international underground mining contractor to partner this development. This has enabled Roxgold to successfully develop the mine over a relatively short time frame with construction commencing in April 2015, first gold being poured in May 2016 and commercial production being achieved in October 2016.This paper discusses key elements of the project development and highlights some of the challenges faced with operating in a remote poorly developed area with a limited mining culture. Furthermore, the authors highlight the key technical and operational aspects that make the Yaramoko project a very successful development project.CITATION:Cope, B and Churi, Y, 2017. The development of the Yaramoko gold project in Burkina Faso, West Africa, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 173–182 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By Xing Zhao, Michael A. Sutton, Vikrant Tiwari, Damien Bretall, Xiaomin Deng, William L. Fourney, Uli Leiste

The dynamic response of a thin aluminum plate subjected to both shallow and deeper buried blast loading was studied. Using a combination of high speed stereo-vision and three dimensional digital image correlation (3D-DIC), sequential stereo images acquired every 38.25µs during blast loading were analyzed to determine full-field deformations and plate motions (displacements, velocities and accelerations, effective surface strain and effective surface strain rate). Measurements indicate that the initial sheet deformation was highly localized for both shallow and deeper blast events, with extremely high velocity and acceleration values recorded during the earliest stages of impact loading. Full field strain and strain rate data indicate that well defined strain and strain rate “maxima” are created in the plate, with the potential of affecting the dynamic plate behavior as well as it local failure.

Jan 1, 2010

Demonstrate the technical feasibility of using nontraditional, low-rank, coal-based fuels and new coal-based technologies for mineral and metallurgical applications. Approach A cooperative research effort was initiated between the Bureau of Mines, U.S. Department of Energy and the minerals industry to extend the application of the fixed-bed gasification process to low-rank Western coals. The research effort enabled cooperators to gain operating experience in the use of hot, raw producer gas for iron ore pellet induration and other high-temperature mineral processes. Researchers were able to gather data regarding the fundamental engineering aspects of the fixed-bed process and gas cleanup for a wide range of solid fuel properties. Applying Fixed-Bed Gasification As a prerequisite to gathering the data needed for the study, the Bureau of Mines designed and installed, at one of its laboratories, a 6.5-ft-diam. single stage, fixed-bed, air-blown atmospheric pressure gasifier. The gasifier was coupled with a hot, raw gas combustion system and iron ore pellet in. duration kiln. The gasifier is rated at 1.5 ton/h capacity of bituminous coal.

Jan 1, 1987

By J. Jeffrey Wagner, Michael J. Bailey, Peter M. Douglass

The Chambers Creek Interceptor Sewer Tunnel project consisted of 2-1/2 miles (4 kilometres) of nominal 9-foot (2.7-metre) O.D. tunnel driven through predominantly glacially overridden soils. Mole-Collucio Construction Company initially elected to drive the entire tunnel with a Lovat TBM. However, this machine could not control the fast raveling ground conditions which developed when the TBM encountered sands overlying very dense, hard glacial till or boulders. As a result, a shield and digger machine was brought in for a 1700-foot (518-metre) long segment. Pumped wells spaced roughly 50 to 125 feet (15 to 38 metres) apart were utilized to dewater about two-thirds of the alignment during construction. Initial support consisted of steel ribs and wood lagging, with a final lining comprised of pre-cast concrete pipe segments grouted in place.

Jan 1, 1985