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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

Past issues of Minerals and Materials have discussed such aspects of the economy as consumption and investment expenditures, interest rates, productivity, and international trade barriers and their effect on the minerals industry here and abroad. In this issue, we will (l) look at recent indications of a possible economic recovery, (2) present 1983 expectations reflecting the results of industry surveys conducted by the U.S. Department of Commerce (DOC), and (3) briefly discuss the contribution of the U.S. mining industry to total gross national product (GNP). THE RECOVERY Throughout most of 1982, DOC's Composite Index of Leading Indicators provided evidence of impending improvement in the economy. The index increased moderately during eight of the months in 1982 and then jumped an estimated 3.6 percent in January 1983 (table 1). While the leading indicators continued to predict improvement, the general economy, as measured by the Index of Industrial Production, continued its slide through November 1982 (table 2). Finally total industrial production increased in December 1982 and continued on an upward path in January and February, as predicted by the leading indicators.

Jan 1, 1983

By Jeff Kravitz, John Kovac, Wayne Duerr

Since 198 1, Federal mining law has required every miner working in underground coal mines to have a self-contained, self-rescuer (SCSR) available for use in emergencies. Some miners that have escaped from fires using SCSR's have reported that they had to remove their mouthpiece to talk during escape, thus compromising the protection afforded by the SCSR. If miners are in thick smoke during an escape, they may have trouble if they become separated from their group. The visibility can be so poor that separation can occur at very short distances. To address this problem, two-way, FM radios were built into the SCSR to improve the ability to communicate should the miners be separated over relatively short distances. The SCSR prototypes built and used in testing included both two-way radios and improved mouthpieces. Comparison studies were conducted using combinations of the new and old mouthpieces, and trials using the radio or not using the radio. Subjective judgments indicate that communication ability was significantly improved using the prototype devices. Communication problems have been encountered with teams using standard voice- powered communications systems. Mine rescue teams perform rescue and recovery work under extremely hazardous conditions, life lines are a standard part of mine rescue team equipment. Leaky feeder and quasi-leaky feeder life line communications systems provide significant improvements over standard systems. These improved systems allow all members of the team to communicate with each other and their base of operations. These innovations will significantly enhance the safety of mine rescue operations.

By authority of the Federal Coal-Mine Inspection Act of May 7, 1941, Public Law 49--77th Congress, H.R. 2082,2/ a Coal-Mine Inspection Division was established in the Health and Safety Branch of the Bureau of Mines. Funds totaling $729,000 for the operation of the division and for other incidental expenses were provided in an amendment to the Department of the Interior appropriation bill for the fiscal year 1942 (H.R. 4590). A small. percentage of these funds was made available on July 1, 1941, and a much greater proportion on October 1, 1941, to defray the expenses of the coal-mine inspection work and incidental activities for the remainder of the fiscal year 1942. The Coal-Mine Inspection Division is charged with administering the act and is required to compile, analyze, publish, and otherwise make available for public inspection the information obtained under it and to transmit such information to the Director of the Census. The act requires also that the information obtained be reported to Congress, with such findings and comments thereon and such recommendations for legislative action as may be deemed proper.

Jan 1, 1943

By Earl Redman

The Juneau Gold Belt portion of the Juneau Mining District has historically had the greatest mining and exploration activity within the district. Between 1880 and 1983, the mines within the Juneau Gold Belt produced 6.7 MM oz gold, 3.1 MM oz silver, and 45 MM lbs lead, which had a total value of about $157,000,000 at the time of production. This report summarizes Bureau of Mines work completed in 1986, the second year of the Juneau Mining District study. Fifty mines, prospects, and occurrences were examined and 638 samples were collected for analysis during 1986. Metallurgical samples were collected from seven deposits and preliminary tests of cyanide amenability have been completed for five of these. The simultaneous discovery by private industry and the Bureau of gold-bearing quartz veins cutting diorite gneiss recently exposed by the retreat of the Herbert Glacier is the most notable result of work during 1986. This location yielded gold values up to 7 oz/st.

Jan 1, 2011

The strike of the Canadian asbestos miners entered its seventh month with increasing signs of early termination. Both unions are in the midst of heavy negotiations with management, and an optimistic industry source predicted that work would resume by October 1. Recession recovery in some segments of the asbestos manufacturing industry is being impeded by lack of fibers, CADMIUM - On September 9, St. Joe Minerals Corp. reduced the price of cadmium metal to $2.75 per pound. The producer price bad been uniformly quoted at $3.00 per pound since June 26, 1975. Subsequently, Amax, Inc. and National Zinc Co. reduced their prices to $2.50 per pound. By mid-September all five U.S. cadmium producers were marketing the metal at $2.50 per pound.

Jan 1, 1975

By M. C. Chapman, P. L. Swanson, A. T. Iannacchione

The National Institute for Occupational Safety and Health (NIOSH) evaluated microseismic activity from three field sites to compare and contrast the characteristics of microseismic emissions from very different geologic, stress, and mining environments. Recently, NIOSH has embarked on a research program to evaluate the use of microseismic monitoring information to identify roof fall failure processes and to assess its potential to warn of unstable roof conditions. Large roof instabilities, such as roof falls and certain roof caving events, have proven difficult to anticipate representing an increased risk to miners working in these inherently hazardous areas. When local failure processes are better understood, appropriate control measures can be engineered to mitigate these hazards. This study used microseismic emissions to help identify three local rock failure processes. It was also shown that analysis of microseismic emissions can aid in assessing the degree of instability associated with these local rock failure processes.

By Steven R. Munts

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied 39,420 acres of the 60,960-acre Skedaddle Wilderness Study Area in order to evaluate its identified mineral resources. There are no known mines or mining operations in the study area. None of the prospects or claims in or within a 1 mile peripheral zone around the study area have recorded production. At least 276 recorded lode, 6 unrecorded lode, and 29 placer claims have been located in and within about 1 mile of the study area. Approximately 191 of the claims are in the study area. Four of these were current in 1985; all four are wholly or partly inside the study area. None of the study area was being explored by private industry in 1985. Metallic and nonmetallic commodities present in the study area consist of gold, mercury, perlite, basalt, pozzolan, stone, and sand and gravel. Perlite is represented by a single deposit which contains 184,000 tons of subeconomic resources in and adjacent to the study area. No other sites contained identified resources. There are no other identified nonmetallic resources in the study area. Occurrences in and near the study area contain small amounts of gold and mercury in vein-type deposits and show characteristics similar to bulk-tonnage, low-grade gold deposits. No base-metal resources were identified. The gold and mercury mineralization and perlite deposit are spatially related to a volcanic center located in the Skedaddle Mountains. Prospects in the Skedaddle Mountains may contain both precious metals and perlite resources, but additional work is required to adequately delineate these areas.

Jan 1, 1987

By Ronald P. Hollenbeck

Shales in the Appalachian Region of Kentucky and Tennessee were sampled and tested to determine their use as raw materials for the manufacture of lightweight aggregate by the rotary-kiln method. Nine samples were obtained from eastern Kentucky and 143 samples were obtained from eastern Tennessee. As a result of preliminary testing of these samples, two sources in eastern Kentucky and 11 sources in eastern Tennessee were resampled for rotary-kiln tests. The rotary-kiln tests showed the two sources in Kentucky and seven sources in Tennessee contained shale that would produce satisfactory aggregate. Lightweight aggregate processed from these nine sources was tested in concrete shapes and was found to be suitable for use in structural concrete.

Jan 1, 1968

By Damon C. Gray

This report contains a recommended program of acoustic research to be conducted by the U. S. Bureau of Mines. The program is directed toward the abatement and control of machinery noise in underground coal mining operations. The study conclusions and specific problem areas which led to the definition of the recommended program are also briefly described.

Jan 1, 1971

By J. A. Organiscak

In the United States, respirable coal mine dust exposures are limited to a 2 mg/m3 time weighted average for a working shift. If the silica content of the sample exceeds 5 percent, the 2 mg/m3 standard is reduced according to 10- (% silica) to limit silica dust exposures to 100 µg/m3. Examinations of dust sampling data collected by the federal coal mine inspectorate showed that roof bolter occupations continue to be at risk for overexposure to respirable silica dust. Testing at the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health assessed the effectiveness of a canopy air curtain for controlling occupational exposures to respirable silica and coal dusts. Initial testing found that zones of higher velocity airflow shrank as distance beneath the canopy increased. This suggested that protection from occupational dust exposures would likely decrease as distance beneath the canopy increased. Further testing revealed that coal dust reduction efficiencies were most affected by changes in interference air velocity and, to a lesser extent, changes in canopy air quantity. However, respirable silica dust percentages under the canopy were not affected by such changes and, in fact, were not significantly different from silica percentages measured outside the canopy. This implied that the air curtain was equally effective on both respirable coal and respirable silica dust particles.

Mine waste and mine reclamation are topics of major interest to the mining industry, the government and the general public. This publication and its companion volume are the proceedings of a conference held in Pittsburgh, April 19-21, 1988. There were nine sessions (50 papers) that dealt with the geochemistry, hydrology and problems of mine waste and mine water, especially acid mine drainage. These comprise Volume 1. The nine sessions (43 papers) that dealt with reclamation and restoration of disturbed lands, as well as related policy issues, are included in volume 2. Volume 2 also contains the ten papers that pertained to control of subsidence and mine fires at abandoned mines. Poster session presentations are, in general, represented by abstracts; these have been placed in the back of both volumes.

Jan 1, 1988

By J. W. Miller

An investigation was begun by the Bureau of Mines in 1948 to determine the preparation characteristics of American coals. Results of the investigation were planned to be reported on a county basis and, from the data developed, to determine: (a) Which coals, either as mined or after beneficiation by conventional preparation, are suitable chemically under present standards for producing metallurgical coke. (b) Which coals require special and more intensive treatment in preparation than is now practiced. (c) Which coals cannot be considered potential sources of metallurgical coke, regardless of preparation. This report is one in a county series and describes the preparation characteristics of the coals of Logan County, W. Va. According to present-day standards for metallurgical coal, many believe that the sulfur content of the coal should not exceed 1.25 percent? Coal with more than this amount has been used for making metallurgical coke, especially when blended with coal containing less sulfur. In this series of reports 1.25 percent sulfur is used as a gage to determine whether or not a coal will be suited for metallurgical coke.

Jan 1, 1957

By Joseph A. DeCarlo

THE TOTAL VALUE of sales of coal-chemical materials in the 10-year period 1948-57 increased 34 percent or at an average annual rate of approximately 3.5 percent. According to the Chemical Industry Facts Book, third edition, 1957, published by Manufacturing Chemists' Association, Inc., the production of industrial chemicals since 1939 "has grown at au average rate of about 10 percent" a year (p. 7). The rapid growth of the chemical industry increased requirements of chemical raw materials at a faster pace than could be supplied by coal carboniza¬tion, and view sources of supply became necessary. The petroleum industry in the past decade increased tremendously the flow of chemical raw materials to the chemical industry through the processing of crude petroleum and natural gas. Whereas coal carbonization supplied most of the raw materials for manufacturing synthetic organic chemicals before World War 11, coke ovens supplied only about 40 percent of the total used in 1957. Although the proportion of chemical raw materials supplied to the chemical industry by coke-oven operators declined, this source of supply is large and important to our economy. In 1957, the value of coal-chemical materials sold, including surplus gas used by producing companies, totaled $358 million, compared with $267 million in 1948. Major factors that contributed to this gain were (1) increased production of all coal chemicals and (2) higher prices for tax and light-oil products. Gains in output of coal chemicals resulted principally from expansion in carbonizing capacity of coke plants owned and operated by the iron and steel industry, as yields of the basic coal¬-chemical materials (tar, ammonia, light oil, and gas) varied only slightly during the 10 years under review.

Jan 1, 1959

By H. W. Gillett, G. M. JAMES

In its work on mineral wastes the Bureau of Mines is studying losses in the melting of nonferrous metals and alloys. The greatest of these losses is that of zinc through volatilization in brass melting, but another and considerable loss is that of aluminum and its alloys in the melting of finely divided material. In order to get some idea of the magnitude of the loss in melting aluminum scrap and to find out what methods of melting were used information was gathered in regard to present practice; also experiments were conducted to obtain some data on the relative merits of different methods. As the experiments could be made on a laboratory scale only, they were not expected to solve the problem entirely, the object in making them being rather-by indicating which methods were of greater promise-to narrow the field over which largescale tests and comparisons need be made by those commercially nterested in the problem of melting scrap aluminum.

Jan 1, 1916

By Ronald M. Lewis

Quadratic functions, Q(hkl), are given to six places in increments of 0.01° for 2? from 00 to 90° for FeKa and from 25° to 180° for FeKa1. The wavelengths used for Fe in the computation are those agreed upon by the Editorial Commission of the International Tables for X-ray Crystallography (1950): FeKa1 1.93597 A.; Feka2 1.93991 A. INTRODUCTION At the Federal Bureau of Mines laboratory, Norris, Tenn. X-ray diffraction crystallography using tubes with iron targets revealed a need for a handy reference for the quadratic functions of iron radiation. The tables presented here were prepared to satisfy that need. The quadratic form Q(hkl) may be expressed in terms of the Bragg diffraction angle 2? and of the wavelength ? as

Jan 1, 1961

By V. F. Parry

"INTRODUCTION During the war period the Bureau of Mines expanded its investigations on western coals principally in connection with Investigations of raw material resources for western steel production. Owing to the expansion of the steel industry, there was some concern regarding the availability of suitable coking coals; end because of the potential steel shortage, the production of sponge iron, using the lower-rank fuels, was considered. Work was conducted by the Bureau of Mines on exploration projects and on testing of coals both at the Central Experiment. Station at Pittsburgh, Pa., and at the Bureau of Mines Station at Golden, Cole.The results of these investigations are being published by the Bureau in several reports of investigations and technical papers. In making this resume of coal investigations, the work done by the Bureau of Mines at Pittsburgh in the Mining and Coal Carbonization Sections will be discussed and the investigations at Golden described in greater detail.INVESTIGATIONS OF WESTERN COALSThe Mining and Coal Carbonization Sections of the Coal Division, Bureau of Mines, under the supervision of A. L. Teeny es and J. D. Davis, respec¬tively, conducted many field investigations to locate and evaluate new sources of coking coals. Drilling explorations were made in Colorado, Wyoming, Utah, New Mexico, and Washington and revealed two important new reserves of coking coal. The first one studied was the Willow Creek bed at Kemmerer, Wyo., which was reported in 1945.3/ A recoverable reserve estimated at 11,200,000 tons was blocked out, and samples of coal were extracted for coking tests. The coking properties of the coal were not quite equal to those of Sunnyside coal, but it was indicated that a 50-percent blend of the Willow Creek with Lower Sunnyside will produce a satisfactory metallurgical coke based on Columbia steel standards."

Jan 1, 1948

As mining operations in the United States (US) have become more productive, controlling the dust exposure of mine workers has become more challenging. In response, US mining operations are applying basic controls at elevated levels and are looking to emerging control tech­nologies in an effort to better control airborne respirable dust levels. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) conducts research to develop and/or improve control technologies that reduce the respirable dust exposure of workers in underground coal mines. The goals of this research involve optimizing the use of water sprays and ventilating air, as well as, evaluating emerging control tech­nologies. An overview of dust controls typically utilized in underground US coal mines will be provided. An update on ongoing PRL research efforts that are evaluating new control technologies will also be presented.

Jan 1, 2008

By L. W. Higley

It is estimated that well over 20 million lb of chromium and 8 million lb of nickel, plus other metal values, are diverted annually to furnace dusts, mill scale, and contaminated swarfs in the domestic stainless and other specialty steelmaking industry. Little inroad has been made toward the in-plant recycling of these wastes to reclaim the metal values. The Bureau of Mines has devised a process for recovering about 90 pct of the chromium and molybdenum and well over 90 pct of the nickel and iron from stainless steelmaking furnace dusts, swarf, and mill scale. Other metals such as manganese are also recovered. Initial laboratory results were confirmed and expanded to include a wide variation of stainless steelmaking waste mixtures. Later experiments have included specialty steelmaking wastes other than from stainless steelmaking. Significantly, the ease of technology transfer has been demonstrated by a number of industrial-sized (19-ton) commercial electric furnace heats, in which the pelletized wastes represented some 10 to 20 pct of the furnace charge, replacing part of the normal scrap charge. Results of these successful large-scale trials are presented. Some information is also presented on incorporation into the pellets of chromium-bearing particulate wastes originating from other than steelmaking production. Cost evaluation indicates the process is economically attractive.

Jan 1, 1982

By F. N. Kissell

The machine-mounted continuous respirable dust monitor (MMCRDM) is a fixed-location area sampling device developed for possible use at the working face of an underground coal mine. This device, based on proprietary technology known as the tapered element oscillating microbalance, has evolved over the past eight years through a cooperative effort of the former Bureau of Mines, MSHA, and the Rupprecht & Patashnick Company in Albany, NY. The capability to measure respirable coal mine dust levels on a continuous basis, rather than depending solely on periodic samples obtained from the traditional coal mine dust samplers, has been a goal in the mining industry for nearly two decades. Recently, an extensive series of laboratory and underground tests was conducted by NIOSH with the cooperation of MSHA and coal operators to test the performance of the MMCRDM In preliminary laboratory testing, the MMCRDM seemed to work well. However, in every underground test, when compared to reference samplers placed close to the inlet, the MMCRDM failed to meet the 25% accuracy criterion specified in the contract under which it was developed. Two reasons explain this failure: First, in most tests the bias (the relative discrepancy between the average MMCRDM concentration and the average reference sampler concentration) was too great. Second, the variability of the samplers used for reference comparison was too large. Finally, the underground testing of the MMCRDMs showed that they are quite unreliable at this stage of development. In the majority of mine tests, no more than 10 shifts of data were taken before the MMCRDM failed to function properly. Major breakdowns, requiring the return of the MMCRDM to the factory for repairs, occurred on average every 28 days. To be considered mine-worthy, MMCRDM reliability must be substantially improved. KEYWORDS Dust, coal dust, dust instrumentation, dust sampling, dust monitoring, black lung, pneumoconiosis