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By Jos. R. Guiteras

This paper describes the operations of the St. Joe Mining & Milling Co. in Boulder County, Colo., as of June 1936. Later a brief visit was made to the mine in September 1936; information obtained at that time has also been recorded. The company operates a gold mine, the Grand Republic, in the Sugar Loaf mining district; a 100-ton flotation mill in Lefthand Canyon near Gold Hill; and a custom sampling punt, the Boulder Ore Sampling Works, at Boulder, Colo.

Jan 1, 1937

By C. C. Hwang

The Bureau of Mines made time-dependent calculations to determine the size of a stationary source fire within a ventilated duct (or passage-way) necessary to ignite a combustible duct liner. The objective of this work was to gain more understanding of what occurs in duct fires and to determine critical conditions for ignition and propagation of mine fires. Heat transfer to the combustible surface includes both convective and radiated components, while the heat is conducted into the combustible and reradiated to the surroundings. The combustible is assumed to ignite when the net heat transfer to its surface is sufficient to raise the surface temperature to some minimum temperature, defined as the ignition temperature. A nondimensional parameter, which characterizes the source-fire intensity in the presence of ventilation flow, emerges as a parameter for a criterion of the critical conditions. The results of these calculations indicated that the minimum fire size necessary for ignition increases with the ventilation rate and duct cross section. These results are compared with experimental results obtained from fires in a 0.8-by 0.8-by Il-m-long duct and a full-scale gallery (2.4-by 2.4-by 65-m). Agreement between the theory and the experiment is good.

Jan 1, 1988

By J. E. Ryan

General Description Due to the extreme cold weather experienced in Flin Flon during the winter months, thought and precaution were necessary in the design of the plant buildings. The machine shop, carpenter shop, drill shop, and coal plant buildings are similar in the building materials used in their construction. They are sided with two-inch shiplap, insulated with celotex and asbestos paper, and covered with corrugated iron on all side-walls. Roofing consists of 2 by 4 lumber on edge, laminated, and further covered by celotex and three-ply roofing. These buildings are heated by means of unit heaters. The heaters are primarily steam-heated radiators, through which the air of the buildings is circulated by electrically-driven fans. Our machine shop is located to the east of, but central to, the main operating buildings of the mine and plant, and is so connected by a net work of tracks as to be able to serve all portions of the entire plant conveniently. The building is divided into two bays, the main bay 53 ft. by 340 ft., and the east bay 24 ft. by 340 ft. The shop office and drafting room, a two-story annex 24 ft. by 30 ft., is located on the west side of the shop. The arrangement within the shop is such as to house conveniently the several departments, namely, heavy machine tool section, repair floor section, boiler shop heavy tool and floor section, blacksmith heavy tool and forge section, tool room, electric welding rooms, stock room, tin and copper shop, and electrical parts and armature winding and repair shop (see Figure 1). All the heavy tools, the repair floor section, and railway tracks are so located in the large open bay as to be fully serviced by an electrically operated 15-ton bridge crane, with a span of 50 feet and a travel the full length of the shop. A standard-gauge railway track, branched off the main line, penetrates the full depth of the building. This track lies along the extreme east side of the main bay, allowing easy entrance and movement of rolling stock and heavy machinery, loaded on standard flat-cars, to the repair floors in the main bay. Eight jib cranes, affixed to building columns, further facilitate the heavy repair work throughout the various shop divisions. Our light and heavy machine tools are standard equipment, not unlike tools used in mine, mill, and railway shops.

Jan 1, 1935

By James C. Barker

In 1981 and 1985-1986, the Bureau of Mines conducted orientation studies of marine placer platinum-group metals (PGM). PGM are derived from the Goodnews Bay ultramafic complex and magnetic surveys show that the complex extends offshore at least four mi. The present seafloor was an emergent foreland as recently as 8000 years ago. High-energy ocean processes are transporting and depositing sediment such that PGM-bearing materials are reworked and later masked by barren littoral drift. Exploration targets include 1) placers formed since present transgression began, and 2) ancient marine and drowned fluvial deposits. Additionally, there is evidence of PGM solution transport and accretion. At least minor values of PGM in Recent lag-type placers and possible submarine strands are concentrated along an offshore scarp incised through glacial deposits into the preglacial surface between Flat Cape and Red Mountain. Other Recent PGM-bearing features include Flat Cape shoal, Chagvan Bay, Salmon River delta, and modern beaches. Ancient placers include possible N-S fluvial systems 2 to 3 mi offshore, a nearshore scarp 50 ft below sea level, and strands adjacent to projected ultramafic bedrock slopes. The existance of ancient placers is dependent on depth of glacial erosion. SEM studies show PGM are principally isoferroplatinum and osmiridium, with minor sperrylite, moncheite, and platiniridium. Gold is a co-product, and concentrates comprise chromite, ilmenite, and magnetite. Beneficiation tests successfully concentrated precious metals from natural blacksand accumulations, but failed to concentrate low-grade lag gravels.

Jan 1, 2011

By Robin P. Gardner

The development and use of short-lived radioactive tracer methods for the on-stream determination of residence time distributions in large-scale ball mills is described. Tests are reported on a pilot-plant ball mill with 0.43 m diameter and 0.86 m length and on an industrial mill with 1.83 m diameter and 2.74 m length. Tests with different tracer feed sizes indicate that the residence time distributions on both mills are independent of charge particle size. Similar tests are planned for a-large ball mill of 4.57 m diameter and 9.30 m length. No safety problems were encountered in these tests and none are anticipated in tests of the larger mill.

Jan 1, 1978

By B. J. Moore

This publication contains analyses and related source data for 234 natural gas samples from wells and pipelines in 21 States and 1 foreign country. All of the samples were obtained and analyzed during calendar year 1975 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and n special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4862 and 576.3 The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the public in general. Seventeen previous publications have presented the results of 10,831 gas analyses prior to 1975. The first 3, Bulletins 486,4 576,5 and 617,6 contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960. The other 14

Jan 1, 1976

By D. F. Hambley

This manual contains a step-by-step procedure for the design of ore passes for open pit mines. The manual is comprehensive and deals with all aspects including location, design, construction and operating considerations. In the construction section, all applicable raising and shaft sinking methods are considered and cost estimates and advance rates provided for each. The design process is divided into several sections - rock flow requirements, support design, dump point design and draw point design. Use of this manual provides open pit planning engineers with a means of designing and assessing the feasibility of ore passes for their operations.

Jan 1, 1983

By Carlos Oré Sánchez

La exploración minera desarrollada en el yacimiento de Poderosa- Pataz conlleva un mejor conocimiento de los controles y la metalogenia de la región. En ese sentido, el presente texto señala el uso del ?18O como indicador espacial en el yacimiento aurífero. Los resultados de esta metodología establecen que los segmentos analizados de las vetas que se encuentran al este, corresponden a los niveles superiores del yacimiento. y en contraparte, las porciones dispuestas al oeste, muestran la zona más profunda del distrito.

May 1, 2014

By Wang Hongwei, Wu Yongping, Cao Peipei, Jiao Jianqiang

Fully mechanized top caving mining of steeply inclined extra-thick seams with variable angles has complex roof rock movement, failure, caving, and filling mechanisms. Moreover, the variable-angle coal seams make rock–equipment stability control challenging. We analyzed rock deformation and failure mechanisms, overburden bearing structures, and working characteristics of supports through physical simulations, field tests, and theoretical analysis of the no. 120210 working face of Zaoquan Coal Mine. Overburden rock movement has distinct regional characteristics, with a large caving height (to the main roof layer) in the upper area, and lower caving height (to the lower main roof) in the lower area. Support loading is regional and unbalanced along the inclined direction. The critical layer of overlying strata migrates, and bearing structures formed by breaking the critical layer exhibit cross-layer generalization along the inclination. The upper region has a cantilever beam structure in the basic roof rock layer; the lower region has an inclined masonry structure with multistage ladders in the breakage basic roof rock layer. Application of a false-inclined working face layout with the tailgate ahead of the headgate and an arc arrangement (radius 28.65 m, arc length 10–20 m) in variable angle areas, and regional control of support working resistance and top-coal caving amounts, control regional failure overburden. Safe and efficient mining was achieved, with the monthly production and recovery rates reaching 344,900 t and 85.86%, respectively. Our results expand the scope of fully mechanized top caving mining and have important theoretical and technological significance.

Nov 23, 2020

By A. G. Gilbert

Paradoxical is the word. The coal industry, despite reach- ing a 22-year high in production (590 million tons), has been tagged as having its back to the wall vis-a-vis its valiant attempts to quench the nation's still unabated craving for coal. What must be even more reassuring to the industry, infected once with rumors of a uranium takeover, is a nation's almost insatiable appetite for electricity. Between 1967 and the summer of 1970, utility stockpiles were being gobbled up, diminishing to 79% of the January 1968 level.

Jan 1, 1971

By Alla D. Mah

Relatively pure aluminum nitride (AIN) recently has been prepared in sufficiently large amounts to permit a variety of experimental studies.4/ Several mechanical and chemical properties have been investigated, which show that this substance has good potentialities as a container for liquid aluminum, gallium, and boric oxide. The present work by the Bureau of Mines was undertaken to obtain thermo-dynamic data pertinent to the calculations regarding thermal stability and reactivity of aluminum nitride. The following measurements were made: (1) determination of the heat of formation from the elements at 298.15° K.; (2) determinations of the heat capacity over the temperature range 51° to 298.15° K. and the evaluation of the entropy at 298.15° K. therefrom; and (3) determinations of the heat content over the temperature range 298.15° to 1,800° K. These data are combined to obtain free energies of formation from the elements between 298.15° and 2,000° K.

Jan 1, 1961

By N. A. Eilertsen

Procedures of mining high-calcium limestone underground at the Kimballton mine of the Standard Lime and Cement Co. in Giles County, west-central Virginia, are described. Drilling and blasting procedures area discussed in detail, and direct mining costs are tabulated in percentage of total cost. Output, about 1,725 tons of limestone a day, is attained with heavy trackless equipment by the room and pillar method of mining modified by benching floors. Operating features include underground air compression, electric-eye control of curtained doorways, use of a single jumbo drill rig for all drilling, and an effective plan for maintenance of equipment. The company's safety program has contributed to an outstanding safe mining record. The mine is integrated with a plant on the property which converts the stone to metallurgical and chemical grade lime.

Jan 1, 1964

By Daniel I. Naupari Escobar

El presente texto señala las técnicas de campo empleadas en la mina Cobriza para el estudio base del sistema de ventilación desde el punto de vista psicrométrico, así como la evaluación del comportamiento termodinámico del sistema y las acciones realizadas para la mejora del mismo. Así también se realiza una introducción del análisis para la aplicación de sistemas de acondicionamiento de aire masivos.

Dec 1, 2014

By Trevor R. Ellis

"The valuation of mineral properties in the U.S. is only partially regulated. The regulations which have jurisdiction or impact appear to have such mainly as a consequence of unintended fallout, since the regulations were designed for other purposes. Court case history can also be important. The combined results are a mixture of bad and good, with important lessons to be learned.Since 1981, the Securities and Exchange Commission has prohibited U.S. listed companies from reporting quantitative estimates of mineralization and the value of mineralization, other than proven and probable reserves. This results in the minerals appraiser (valuator) working with a shortage of data in his everyday work, both on the subject property and in sales analysis.Between 1989 and 1995, all 50 states and essentially all Federal agencies adopted the Uniform Standards of Professional Appraisal Practice (USPAP) for real property appraisals (valuations). The major national appraisal societies also require their members to abide by USPAP. A significant portion of minerals appraisals must now follow these standards. This paper will discuss the content of USPAP. It provides a very good framework for the valuation of a minerals property or a mine, both as real property and as a business. However, the credentialing standards for real property appraisers are now prohibitive for minerals appraisers."

Jan 1, 2003

By B. K. Shibler

As a part of the Bureau of Mines' intensive; 'investigation of domestic manganese deposits, ore-dressing studies were conducted on three samples of oxide and silicate manganese ores from various Wyoming properties. The samples wore as follows: 1. A 2-ton sample of ore was obtained by a Bureau engineer during examination of the Caulkins-McGuckin property in the center of Crook County, 10 miles north of Sundance, Wyo. The ore body was described as a vein deposit in rhyolite porphyry. 2. The J. B. C. Mining Co. submitted a 1-ton sample of oxide manganese ore from a property located 44 miles northeast of Rock River in Albany County, Wyoming. 3. A 1-ton sample of oxide-silicate-ore was obtained by a Bureau examining engineer from the Gheen property in the northeast corner of Washakie County, Wyo. The ore body was described as a replacement deposit in a country rock of silicified limestone. As the samples differed widely in physical and chemical characteristics and also in their response to methods of concentration, ore from each property was considered a separate ore-dressing problem.

Jan 1, 1949

By F. O. Verret

Several grindability tests were developed over the years to design grinding circuits or optimize existing operations. Each test has its own strengths and weaknesses and it is imperative to select the proper test procedure(s) to meet project deliverables and minimize the risk of a project. Pilot plant testing of large bulk samples historically constituted the traditional approach for AG or SAG design, but was gradually replaced by small-scale tests. Nowadays, conducting grindability tests requiring only a few kilos of material on several samples is a more typical approach to grinding mill design. This paper summarises the requirements and deliverables of various bench-scale test procedures, their strengths and weaknesses, and cases where AG/SAG pilot testing should still be performed.

Jan 1, 2012

The global mining industry is perceived to be a world leader in sustainability reporting û with a 2008 Ernst & Young survey placing four mining companies in their top five performers in sustainability reporting in South Africa. There is certainly good evidence to support this finding, but there remain many ongoing issues with respect to sustainability reporting and some important areas for improvement by mining companies globally. This paper begins with a broad (but brief) review of sustainability and the technical basis for reporting against a wide range of typical indicators or measures on the environmental aspects of mining. The various protocols, frameworks or systems are then reviewed, with a particular focus on the Global Reporting Initiative (GRI) and its associated mining sector supplement (including the evolution from environmental to sustainability reporting). A wide-ranging survey of reporting by mining companies is presented, including detailed analysis of 2007 and some commodity sectors over time. Examples of reported data are synthesised and analysed, focusing on their accuracy, consistency and utility for accurate assessment of the life cycle impacts for minerals and metals. A number of areas are identified for improved reporting by all mining companies, including water resources and consumption, energy consumption, process inputs (eg acids, solvents, etc), pollutant emissions, including greenhouse emissions, mine site data (not aggregate company totals) and finally rehabilitation and land status. Given the nature of mining, and considering parallels between æpeak oilÆ and the mining sector, it is critical that the state of sustainability reporting continue to evolve and improve û both in the number of companies using the GRI but also in the level and consistency of data being reported. Overall, the paper presents an important review of the present state of the art in sustainability reporting for mining, and provides a range of insights into ways to help improve reporting in the future for all mining companies.

Jan 1, 2009

By R. V. Ramani

In this report, the application of the Open Pit Materials Handling Simulator (OPMHS) to a mine located in Illinois using bucket wheel excavator (BWE) and a stripping shovel in tandem for overburden removal is described. The specific objective of the study is to demonstrate the application of the simulator to analyze mine planning and scheduling problems and to generate and analyze alternatives for increased production. On the basis of the simulations it was concluded that the maximum productive capacity of the system in raw coal was around 3000 tons per shift. At this production level, the equipment combination and availability also satisfy the match requirements for the stripping shovel and the BWE, and the overburden and coal removal systems. Several alternatives requiring new equipment are proposed and analyzed for increasing production. However, no economic analyses of these proposals were done.

Jan 1, 1977

By E. J. Gleim

In keeping with past custom, it is the purpose of this publication to bring up to date previously published lists of equipment that meets safety standards of the bureau of Mines so that the mining industry may be informed as to the development and availability of equipment that can be used safely. The present lists supplement those in Bulletin 543. Permissible Mine Equipment Approved to January 1, 1953; Information Circular 7722, Permissible Equipment Approved During the Calendar Years 1953-54; and Information Circular [40], Permissible Equipment Approved During the Calendar Years 1955-56. These [ew] lists also contain equipment meeting those standards revised since the last listing. A revision of Schedule 16C (now Schedule 16D4/) was officially approved on September 28. 1958. Schedule 29 was another standard revised in 1958. The revision was officially approved on September 8. 1958, and is known as Schedule 29A5/ .

Jan 1, 1960

By E. C. Fitch

This report discusses fire-resistant hydraulic fluid safety from three different directions. First, results of a survey prepared for the Fire Resistant Hydraulics Journal by the staff of the Fluid Power Research Center are analyzed. Second, operational limitations of fire-resistant hydraulic fluids are examined. Finally, laws and standards of various foreign countries are investigated. Three conclusions are derived from a close study of fire-resistant hydraulic fluid safety from these three directions. First, a significant number of experts in the fluid power industry are no in agreement about aspects of fire-resistant hydraulic fluid fire-resistance and toxicity. This indicates a need for more in depth research. Second, the use of fire-resistant hydraulic fluids involves a compromise between the decreased fire hazards and increased toxicity and machine incompatibility problems. Finlly, major foreign governmental agencies have thorough laws and standards concerning fire-resistant hydraulic fluids. These laws and standards may provide a solid framework for further international research into fire-resistant hydraulic fluid safety.

Jan 1, 1979