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By A. T. Iannacchione

Underground limestone mines typically use the room-and-pillar method of mining in the generally flat-lying limestone formations. In some cases the dip may exceed 5° which can result in unique roof instability problems. Stability may be further exacerbated by the presence of horizontal tectonic stresses. Field studies and numerical model analyses are combined to assess the affect of the dip in various stress conditions. The results showed that where the horizontal tectonic stresses are sufficient to cause intact rock failure, increasing dip results in increased failure potential. The effect of the dip is greater when the maximum horizontal stress is parallel to the dip. Two case studies are presented and evaluated against the findings of stress analysis results. The study showed that the empirical rules of orienting headings parallel to the maximum stress are generally applicable to dipping excavations, except when mining in the up-dip direction. The importance of accurately determining the orientation of the maximum horizontal stress is emphasized because the window of favorable orientations relative to the stress is small.

By Thomas E. Howard

Man has been engaged in the construction of tunnels in. rock for several thousand years. During that time, methods of tunneling have changed drastically. Hordes of men chipping away at the tunnel face have been replaced by mechanical drills and explosives and by tunnel boring machines. Spoil is no longer carried on the backs of humans, but is now removed by trains, trucks or conveyor systems. These and other changes have had the effect of greatly increasing the rate of tunneling, while at the same time, greatly decreasing the potential dangers to workmen. Although the techniques, equipment and material used for tunneling are being continually improved, rock tunneling is still a slow and expensive process. Significant improvements and innovations are needed to reduce the cost and time required for tunneling if we are to fully utilize the subsurface to aid in the solution of urban problems and in the conservation of resources. This report is intended to facilitate the orderly development of tunneling technology by focusing attention on the inadequacies of rock tunneling and the improvements that are needed. The data presented were derived from the results of a comprehensive questionnaire that was completed during the summer of 1969 by more than 600 individuals and organizations in 17 countries. Table 1 lists the countries and the number of replies from each. Appendix A contains a summary profile of the national responses, while the text presents the results and a brief analysis of the conclusions that might be derived from the data in the questionnaire. The data shown in Appendix A represent the consensus opinion of each of the 17 nations without regard to the number of individual replies or the amount of tunneling activity that is represented. The national consensus was determined for each country by a plurality of the individual responses, in some cases modified by the opinion of the rapporteur. Tire above procedures can lead to situations which are misleading. For example, experience and activity arc a rational basis for analysis; but, if national replies are weighted on this basis (i.e., number of responses), informed and valuable opinion of less active countries would probably be overwhelmed and lost. In analysing the data on the basis of national responses without weighting, it becomes apparent that many of the same problems exist under a given set of conditions regardless of the number of tunnels that have been driven.

Jan 1, 1970

The Thermo-MIE personal DataRAM dust monitor (pDR) is a light-scattering instrument approved for use in gassy underground mines by the U.S. Mine Safety and Health Administration (MSHA). However, the use of light-scattering monitors has been inhibited by concerns about inaccurate readings resulting from changes in dust size distribution and composition, as well as concerns about the impact of moisture in the mine air. Because of this concern, the National Institute for Occupational Safety and Health (NIOSH) evaluated the pDR using available data from laboratory tests and mine surveys. The data show that accuracy can vary widely from test to test and mine to mine. In most cases, the results can be improved by using a companion gravimetric measurement to adjust the pDR data.

Jan 1, 2006

By Sam McNary

The U.S. Bureau of Mines used the East Fork Pine Creek watershed to conduct a pilot study for an inactive and abandoned mine lands inventory, during which techniques and methodologies would be developed for subsequent inventories. A total of 177 waste dump samples, 191 mill tailings samples, and 36 stream sediment samples were collected. Water samples were collected from 18 sample sites during five sampling events. Waste dump, tailings, and stream sediment samples were analyzed for antimony, arsenic, cadmium, copper, iron, lead, mercury, and zinc. Results indicate a multidisciplinary approach is necessary: disciplines should include geology, geostatistis, geochemistry, geophysics, biology, hydrology, and remote sensing; small prospects do not generally contribute to watershed contamination, major mine and mill sites may contribute metal enriched sediment of metal enriched water; speciation studies and bioavailability studies are important.

Jan 1, 1995

Nineteen eighty-seven was a year of significant change in the Bureau of Mines-change to help it better adapt and respond to the wide range of new challenges facing the U.S. mineral industry. The Bureau has been regarded as the world's premier mineral information and research agency. Its authoritative, comprehensive data and its pioneering research have contributed significantly to the minerals position of the United States. Yet no organization in today's complex, dynamic world, with its rapidly advancing technologies, can afford to rest on its laurels. Mission and program must be constantly fresh and relevant to the day's issues and problems. Moreover, rather than reacting to events, the organization must strive to anticipate and prepare for them. It must have a sense-a vision, if you will-for the future.

Jan 1, 1987

The Aluminum Company of America (Alcoa) announced plans to shut down production at the remaining two potlines at its Point Comfort, Texas primary aluminum smelter due to the increased costs of natural gas. Total capacity of the facility, which had been partially closed since 1976, was 185,000 tons per year representing 3.6 percent of current capacity in the United States. There were practically no price movements in March on 99.5 percent aluminum ingot, with producers at 53¢ per pound and dealers, 48¢-48.5¢. BISMUTH The March selling position of U.S. producer metal was held at $3.50 per pound. In contrast, east coast dealers and traders adjusted their quotes from $2.55-$2.60 to a wider range of $2.40-$2.60.

Jan 1, 1978

The Full Scale Model Roof Bolt Test System described herein was designed, fabricated, erected, and installed by MSA Advanced Systems Division for the U. S. Department of Interior, Bureau of Mines, Spokane Research Center. It was furnished under USBM Contract No. 50271014 and Modifications. The test system is intended for use by the Bureau of Mines to run comparison tests on roof bolt systems. The mine entry cross section is made from special concrete pillars and roof slabs. They are constructed within a steel beam frame with hydraulic operated cylinders to apply loads that simulate the action of mining overburden. The frame is designed so it can be disassembled for replacing the concrete in subsequent tests. A computer and data acquisition system is furnished to control the load application and measure and gather data.

Jan 1, 1979

A preliminary research and development program dated April 25, 1974, was prepared for Development Engineering, Inc. (DEI) for laboratory, field and other engineering studies on the disposal of retorted oil shale. This program was revised and published as a final document dated December 17, 1974. The document included discussions on the peculiarities of retorted shale materials to be investigated and discussions of the various laboratory and field tests which would need to be conducted to define their physical and chemical properties. The proposed research and development program was divided into eight work phases as follows: I Program Development. II Exploratory Laboratory Tests on Old U.S.B.M. Retorted Shale. III Laboratory Tests on Pilot Plant Retorted Shales. IV Laboratory Tests on Retorted Shales from the Semi-Works Plant.

Jan 1, 1976

By John R. McWilliams

The technological and economic pattern of the U. S. mining industry has undergone a rapid and continuing change since World War II. To provide realistic up-to-date cost data and to disseminate knowledge of technical developments, the Federal Bureau of Mines, with the cooperation of individual mining companies, is presenting a series of mining methods and costs reports similar to those it issued before 1939. Shaft sinking has always played an important part in mine development and [ration] and is an appropriate subject for this series of reports. Shafts [are] especially important in areas such as the Coeur d'Alene district of Idaho, where every major mine is served by one or more shafts and shaft sinking is in progress at one mine or and her almost continuously.

Jan 1, 1960

By d&apos, Kathleen J. Amico

THIS SUAMMARY is shown in Minerals Yearbook volumes I and III of this series on mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, and on the principal minerals imported into and ex- ported 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, 1962

This: symposium was sponsored by the Bureau of Mines, U.S. Department of the lnterior, in order to critically examine the state-of-the-art of sulfide flotation chemistry and to define current and emerging problems that should be emphasized in future fundamental research. The topics covered through invited papers include both reviews and recent research results in the areas of thermodynamics of reagent-mineral interactions; collector adsorption processes; the effects of solid-state point defects on flotation; activation and deactivation phenomena; the electrochemical role of oxygen in sulfide flotation; environmental problems in flotation; and selective flocculation of fines. Papers riving perspectives on flotation research in relationship to our national mineral requirements and the relationships between industrial flotation research and academics are also presented. An edited summary of the symposium follows the papers.

Jan 1, 1980

U.S. Bureau of Mines contract H0122053, "Improved Sensors and Fire Control Systems for Mining Equipment", was an investigative effort involving: ? Study of the fire problem on large mobile mining equipment ? Identification of equipment most prone to fire, to serve as a design case example ? Design of an improved fire protection system ? Demonstration of the developed system This effort was performed during the period June 1972 through May 1973, and was conducted in two phases. Phase I, June through November 1972, was devoted to identifying the fire problem and developing and evaluating design criteria. Phase II involved translating the design into hardware and demonstrating its effectiveness during actual fire tests, first on a wooden mockup of a truck, then on an operating truck at a working mine site.

Jan 1, 1973

THE Synthetic Liquid Fuels Act. (30 U.S.C., 321-325, and amendments) became law April 5, 1944, and a period of intensive research and development in this field was begun by the Bureau of Mines. As part of this program, bulletins were published on pressure hydrogenation.3 the Fischer-Tropsch synthesis,4 anal oil shale.5 The Bureau also has published a short bibliography on coal gasification,6 mostly of a theoretical nature. Because coal gasification is prerequisite to either the Fischer-Tropsch or coal-hydrogenation processes, publishing this sizable collection of technical information in this form will be valuable. The material will be presented in three parts, as follows: I. United States Patents. II. United Kingdom Patents. III. Other Foreign Patents. The domestic patents for this bulletin were collected between 1953 and 1955.

Jan 1, 1960

By William C. McBee

Prompted by forecasts of a sulfur oversupply, the Bureau of Mines, U.S. Department of the Interior, is conducting research on potentially large-scale uses of this commodity to extend or replace such construction materials as asphalt, cement, and mineral aggregates. Through these efforts, paving materials have been developed in which sulfur replaces up to 50 pct of the asphalt normally present and which can be prepared and placed with existing mixing and paving equipment. Laboratory properties and design methods for this direct mixing process are described along with properties obtained on small-and large-scale field demonstration projects. These properties are compared with those obtained from control materials prepared without sulfur additions. Monitoring for toxic gases during laboratory and commercial mixing and paving operations is discussed also.

Jan 1, 1978

By Robert A. Cummings

A rock mass classification system has been developed for recommending drift support requirements in block caving mines. This development follows a two-year program incorporating field observations of support practice and performance in rocks of different classes, at several U. S. block caving mines. Popular rock mass classification systems presently in use for tunneling were applied at the various field sites; and were evaluated for conformance with caving mine support requirements and for general utility to caving mine operations. The developed system (MBR System) accepts readily-obtainable engineering and geologic data to yield a rational estimate of support requirements. The background and development of the MBR system is described in this report (Volume I). The use of the system is given in the Manual, a separate volume (Volume II).

Jan 1, 1984

In the spring of 1944 the Congress passed Public Law 290 (58 Stat. 190, 30 U. S. C. Sec. 321) "authorizing the construction and operation of demonstration plants to produce synthetic liquid fuels from coal, oil shales, agricultural and forestry products, and other substances, in order to aid the prosecution of the war, to conserve and increase the oil resources of the Nation, and for other purposes." Section 2 reads: "In order to carry out the :purpose of this act, the Secretary of the Interior is authorized- (a) to conduct laboratory research and development work, and, with pilot plants and semi-works plants, to make careful process engineering studies, along with structural engineering studies, in order to ascertain lowest investment and operating costs necessary to determine the best demonstration plant designs and conditions of operation;

Jan 1, 1948

By John B. Bennett

This Bureau of Mines report presents a method of standardizing forecasts of mineral consumption that attempts to resolve the problems caused by the use of different data bases, different definitions of minerals consumption, and different base years for making projections. Using this method, forecasts of U.S. and world mineral consumption, in the year 2000, for nine commodities (aluminum, chromium, cobalt, copper, manganese, nickel, tin, tungsten, and zinc) are standardized and compared. Also selected forecasts or associated growth rates are used to generate implied values of consumption for 1980-83, which are then compared to actual values of consumption for 1980-83. The economic growth predictions underlying the forecasts are examined, and some general conclusions are drawn. A description of each methodology used to generate these forecasts is given in an appendix.

Jan 1, 1986

In the spring of 1944 the Congress passed Public Law 290 (58 Stat. 190, 30 U. S. C. Sec. 321) "authorizing the construction and operation of demonstration plants to produce synthetic liquid fuels from coal, oil shales, agricultural and forestry products, and other substances, in order to aid the prosecution of the war, to conserve and increase the oil resources of the Nation, and for other purposes." Section 2 reads: "In order to carry out the purpose of this act, the Secretary of the Interior is authorized- (a) to conduct laboratory research and development work, and, with pilot plants and semi-works plants, to make careful process engineering studies, along with structural engineering studies, in order to ascertain lowest investment and operating costs necessary to determine the best demonstration plant designs and conditions of operation;

Jan 1, 1948

By Michael E. Henderson

The U.S. Bureau of Mines (BOM) constructed the Hydraulic Transport Research Facility (HTRF) to investigate the hydraulic parameters relating to the transport of coarse coal. To achieve these goals in a timely and efficient manner, the Bureau contracted to Boeing Services International, Inc. (BSI) the responsibility of operating the HTRF and providing technical support. This data report is a summary of the testing and data results for the period from 6 September to 9 September 1983. The testing covered herein is for coarse 2-in by 0 (minus 50 mm) Pittsburgh Seam run-of-mine (ROM) coal in a 12-in (300 mm) pipeline, at velocities ranging from 8 to 16 ft/s (2.4 to 4.9 m/s) and at concentrations ranging from 15 to 50 pct.

Jan 1, 1985

By Causey J. Douglas

In 1988, at the request of the Bureau of land Management, the U.S. Bureau of Mines studied part of the 13,460-acre Owyhee Breaks Wilderness Study Area (OR-003-059) in order to evaluate its identified mineral resources. The study area is in Malheur County, OR, about 27 miles northwest of Jordan Valley. No mineral resources were identified in the study area during this investigation. There is an occurrence of jasper along Birch Creek and an associated occurrence of zeolite in some tuffs. In the northern part of the study area is an occurrence of bentonitic clay containing less than 40,000 tons. Much of the area is covered by landslide blocks, colluvium, earthflow deposits, and talus, composed of Tertiary-age volcanic rocks. The upper plateaus are capped by Tertiary-age basalt.

Jan 1, 1989