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By Kray Luxbacher, Mario Karfakis, Erik Westman, Peter Swanson

Three-dimensional velocity tomograms were generated to image the stress redistribution around an underground coal longwall panel to produce a better understanding of the mechanisms that lead to ground failure, especially rockbursts. Mining-induced microseismic events provided passive sources for the three-dimensional velocity tomography. Surface-mounted geophones monitored microseismic activity for 18 days. Eighteen tomograms were generated and high-velocity regions correlated with high abutment stresses predicted by numerical modeling. Additionally, the high-velocity regions were observed to redistribute as the longwall face retreated, indicating that velocity tomography may be an appropriate technology for monitoring stress redistribution in underground mines.

By Bertrand L. Johnson

Barite, the natural sulfate of barium (BaSO4), is the most important barium mineral. Normally it is white (opaque to translucent), but impurities sometimes render it yellow, gray, blue, brown, red, or black. Brown or red stains are commonly caused by iron oxide. Barite is unusually heavy (specific gravity, about 4.5); in fact, it is one of the heaviest of the nonmetallic minerals. It is brittle and fractures unevenly. The hardness of barite ranges from 2.5 to 3 but is usually about 3. It can be scratched by a copper coin. Pure barite contains 65.7 percent BaO and A.3 percent S03. Much of the crude barite ore mined, however, contains impurities; thus it has a lower content of barite and consequently less barium oxide. Commercial analyses show its total BaSO4 content. Barium also occurs in nature as the mineral witherite (BaCO3), which, however, is not common in the United States, and commercial deposits have been found only in California. Witherite is a yellowish-white, light-gray, or Kite mineral with a specific gravity of about 3, a hardness of 3 to 4, and an uneven to subconchoidal fracture.

Jan 1, 1941

By Mark S. Sanders

This report is a review and synthesis of the published literature dealing with personal equipment items used by low seam coal miners. This report reviews the following items of equipment: headgear, outer garments, respirators, cap lamp, gloves, knee pads, footwear, boots, helmets, ear protection, eye protection. Recommendations for further research and development are included.

Jan 1, 1978

By J. B. Gayle

The merits of the various methods for dry-quenching coke have been the subject of numerous publications and almost equally numerous controversies for the past 40 years.5/ Most investigators have concluded that dry quenching is advantageous. Some have based their arguments on the improved physical properties of the resultant cokes. Others have claimed little or no improvement and have based their arguments on the economies acquired from the recovery and utilization of sensible heat. The extent to which the method of quenching influences the properties of the resultant cokes is of importance in connection with the operation of both commercial and experimental ovens. On the other hand, the recovery and utilization of sensible heat are economic problems related solely to commercial oven operation and- depend on the method of dry quenching used and the demand for a low intensity energy source. The scope of the present Bureau of Mines investigation has been limited to a comparative study of the properties of wet- and dry-quenched cokes produced from six coals and blends carbonized at flue temperatures of 2, 000° and 2,400° F. in the Tuscaloosa oven.

Jan 1, 1959

The Bureau of Mines is responsible for a broad spectrum of programs for meeting the diverse and changing mineral resource needs of the Nation. These programs are managed by the Director and two Deputy Directors, who formulate general policy and program direction from the Washington, D.C., headquarters. A senior advisory staff, consisting of the Chief Staff Officer, Chief Scientist, and Chief Mining Engineer, provides advice and consultation to the Director on a wide range of scientific and technical matters and acts on behalf of the Director to maintain liaisons with other government agencies, mineral industries, and professional societies. Bureau program activities are classified into two major functions: (1) Developing new and improved technology that will make the production and processing of minerals more efficient, safer and more healthful for mineral workers and the public, and more compatible with a quality environment.

Jan 1, 1979

By Joseph L. Condon

Fifteen shots of three explosives with charge weights of 0.52, 1.1, 3.1, and 5.1 kilograms were fired in a pond to study the seismic effects of detonating explosives in water. Shock pressures and bubble periods were measured with pressure transducers in the water. Vibrations were measured on land in three orthogonal directions with particle velocity gages. Statistical tests indicated that a charge weight exponent of 0.43 best scaled the data. While shock pressures and bubble periods showed considerable differences in explosive performances, the amplitudes of ground vibrations showed less difference, and one prediction equation was therefore derived to estimate vibration amplitudes from all the explosives.

Jan 1, 1970

By C. W. Davis

This paper is the second of a series of progress reports on a study, of the hydrometallurgy of manganese which is being conducted in an endeavor to make possible utilization of the large deposits of low-grade domestic manganese ores that occur in several States. There are at least four processes in which a knowledge of the action of SO2 gas on manganese oxides at elevated temperatures may prove of value. One ,of these involves dissolution of manganese from ores. The Bureau of Mines has investigated the hydrometallurgy of manganese by a process in which SO2 gas, a waste product at many smelters, is passed into water to form a solvent for manganese. Although Several manganese minerals acre readily dissolved, rhodochrosite (MnCO3) was attacked but superficially.§. Recent experiments have shown that a roast at 650 to 900°C converts the manganese of rhodochrosite to a form that is quickly dissolved by a weak SO2 solution. Introduction of smelter gases containing as much as 5 per cent SO2 during such a roast would not add much to the cost of the operation and might result in the formation of considerable water-soluble manganese sulphate.

Jan 1, 1930

By C. W. Davis

This paper is the second of a series of progress reports on a study of the hydrometallurgy of manganese which is being, conducted in an endeavor to make possible utilization-of the large deposits of low-grade domestic manganese ores that occur in several States. There are at least four processes in which a knowledge of the action of S02 gas on manganese oxides at elevated temperatures may prove of value.

Jan 1, 1930

THIS bulletin presents all analytical and lest methods regularly used by Bureau of Mines laboratories for characterizing coal and coke. To provide better service to coal producers and consumers, the scope of this bulletin has been expanded to include important test methods used to evaluate coal properties for commercial processing. The methods described will prove valuable to all persons interested in analyzing and testing coal and coke.

Jan 1, 1967

By Frank B. Fulkerson

Mining began in Pend Oreille and Stevens Counties about 1885, Lead and zinc have been the principal products, and the area has supplied nearly all the output of these metals in the State. Fend Oreille County's output of lead and zinc from 1902 to 1956 was 110,700 and 229,600 tons, respectively. The Stevens County total was 54,100 tons of lead and 87,600 tons of zinc. Copper ore was produced mainly from the United Copper mine, Chewelah district, from 1912 to 1920; the principal gold mine was the First Thought, Orient district, which was active from 1904 to 1942. Approximately 225 mines and prospects produced; most of the ventures were on a small scale. The total value of gold, silver, copper, lead, and zinc produced from 1902 to 1956 was $75.2 million in Pend Oreille County and $39.4 million in Stevens County. INTRODUCTION In compiling the figures for this report, use was made of Bureau of Mines permanent records of nine production, the annual tabulations of producing mines, and the Minerals Yearbook. Requests to publish individual data, obtained from the annual production canvass, were made to the latest recorded operators of all mines in the area. Response to this request was good; therefore, it was possible to make the tables nearly complete. In a few instances the producer requested that the production data remain confidential, and in others it was not possible to reach the mine operator at his last known address. The district and county tables combine statistics for all mines, including those mines whose output could not be published separately.

Jan 1, 1958

By W. D. Mcmillan

Important reserves of nickel ore occur in the Levies district in Oriente, Cuba. The area is mountainous and mostly covered by heavy vegetation. The ore bodies comprise surface tracts of nickeliferous laterite underlain with decomposed serpentine of ore grade. The Cuban Nickel Co., a wholly owned United States Government corporation, owns a plant for leaching the nickel from its ores at Nicaro, Oriente, Cuba, Between December 1943 and March 31, 1954, 5,902,225 short tons of ore was treated, with a recovery of 116,206,519 pounds of nickel (52,711 metric tons). In 1953, 1,330, 224 short tons of ore was mined and 27;"3,129 pounds of nickel produced. The Cuban Nickel Co. also owns a townsite, with the necessary facilities, mining equipment, and 11 miles of railroad. Ore for the plant has been produced from the Ocujal-San Juan claims on lends owned by the Nicaro Nickel Co., a sub¬sidiary of Freeport Sulphur Co. The Government enterprise is man-aged by the Nickel Processing Corp. The Cuban Nickel Co. has denounced mineral concessions and has purchased other claims from private owners.

Jan 1, 1955

By Stanley A. Feitler

This Bureau of Mines report deals principally with the resources and economic aspects of feldspar in the United States east of the Mississippi River. Although in a strict sense, all phases of the feldspar industry affect its economic structure, emphasis in this study is on supply, demand, and marketing. Although feldspar was originally mined for use in the manufacture of pottery and other ceramics, the glass industry, which began to use feldspar in the mid-1920's, now consumes more than half of the annual output. Most mining is open cut, and the methods used are similar to those used in mining crushed b stone. Excess plant capacity has been chronic, and production is usually about 30 percent of capacity fur the industry as a whole. Since 1947, feldspar consumption has grown more slowly than the average for all U.S. industry. This has fostered intense competition, especially for the glass market. Prices have not kept pace with inflation, and profits are small. The trend of consumption through 1970 for glass feldspar is expected to be upward; less rapid in consumption of ceramic feldspar is anticipated.

Jan 1, 1967

By J. P. Walker

"INTRODUCTION Sponge iron has been made commercially since 1912 at a Swedish ceramic plant; and the product, known as Swedish disk-type nagger sponge iron, has an excellent reputation as a superior furnace feed wherever high-grade steels are made.The general procedure for making brickyard sponge iron was described frequent in Swedish technical journals before 1932 and at that time consisted in filling clay refractory containers, called saggers, with iron ore plus the necessary quantity of solid reducing agent and then firing in an ordinary ceramic kiln. Two types of sponge iron were made in this way: (1) An inferior, high-sulfur product obtained by mixing the ore and solid reducing agent; and (2) a high-grade, low-sulfur product made by filling the sagger with alternete layers of unmixed ore and reducer, yielding sintered disks of metallic iron particles.Swedish disk-type sponge iron of interest to the steel industry because it has a very low sulfur content, even when made by the use of low-grade, high-sulfur coals for reducing and firing. The Swedish product also contains little siliceous gangue residue and is almost phos¬phorus-free. To those features must be added the high metallic-iron content -90 to 96 percent - and freedom from even small amounts of the metals that are undesirable in steel making.The details essential for successful operation of this procedure are not known, especially as regards improvements said to have been made since 19;2. The Bureau of Mines therefore decided to determine some of these missing details, and this report records the results of the first set of experiments on the manufacture of brickyard or sagger sponge iron."

Sep 1, 1945

By J. S. Stachulak, G. H. Schnakenberg

The objective of the Diesel Emissions Evaluation Program (DEEP)-sponsored project at Inco's Stobie mine was to conduct a long term field evaluation of diesel particulate filter (DPF) systems available to the underground mining industry. Some of the major issues studied were criteria for selecting the filter media, means of DPF regeneration, efficiency of DPF systems and the occurrence of unwanted secondary emissions, and reliability and durability of DPF systems. Nine state-of-the-art diesel particulate matter (DPM) filtration systems have been retrofitted to heavy-duty and light-duty vehicles and have been subjected to extensive long-term in-mine evaluation. Periodic efficiency tests were conducted at various stages of the study (2001, 2002 and 2004) to establish in-use efficiencies and durability of the tested DPF systems. The results were used to assess the effects of the filter systems on the concentrations of particulate matter, nitric oxide, nitrogen dioxide and carbon monoxide in the vehicle exhaust. The variety of filtration systems and regeneration concepts used in this study offered the opportunity to investigate their advantages and disadvantages. This paper also offers a review of selected experiences with the installation and operation of the DPF systems on underground mining vehicles at the Inco Stobie Mine.

By Frank E. Williams

Nuclear detonation data were accumulated, studied, and evaluated by the Bureau of Mines to visualize how nuclear explosives might be used in a shale?-oil industry, The evaluation shows that the Green River Formation at the semi-isolated locale of Piceance Creek Basin, in northwestern Colorado; is thick and widespread enough to warrant consideration of nuclear mining in lieu of conventional methods, Because cost data for nuclear explosions are limited; cost comparisons are made largely by assumptions. Also described are the history of the shale-oil industry, the geology and size of oil-shale resources; and conventional mining methods and processing technology.

Jan 1, 1969

By D. Harrington

United States newspapers of 25 or 30 Years ago ran headlines every few weeks telling of some mine disaster. Each disaster was a first-page attraction for a day or so then was forgotten until the next sensational event, frequently another mine disaster, a few weeks later. Interspersed with the large mine disasters were the so-called ?snipping? mine accidents that caused the death of one or two mine workers. The summation of mine fatalities of all types usually exceeded 3,000 a year, and nonfatal accidents to workers in mines of the country approximated 250,000 annually. From 1906 to 1910, inclusive, there were 84 major explosion disasters (about 17 per year) in. United States coal mines. The resulting fatalities totaled 2,388 for the 5-Year period. These frightful catastrophes helped the number of fatalities in coal mines of the country to reach the enormous total of 13,288 for the 5 years, or an average of 2,658 per year.

Jan 1, 1940

By Doris M. Hyde

The economy of Belize continued to show a very slight but still positive growth during 1986. The gross domestic product (GDP) was estimated to have been about $164 million,2 almost the same as those of 1984 and 1985. Foreign investors looked favorably on Belize because it had remained isolated from the sometimes turbulent political and social strife elsewhere in Central America. Reportedly, in late 1986, Guatemala had decided not to pursue its claim to Belizean territory and to give full recognition to that country. Discussions were to be held regarding any matters of mutual concern. New investment possibilities were oriented toward agriculture or manufacturing endeavors. Except for some interest in petroleum exploration, the minerals sector remained limited to the quarrying of construction-related materials.

Jan 1, 1988

By William D. Dodge

A typical quality program plan is presented for explosion-proof (XP) electrical enclosures. The plan is suggested for manufactures of XP enclosures which are to be certified by MSHA for mining use. The plan describes the quality system, organization and implementing mechanisms which are to be applied in the manufacture and delivery of certified XP enclosures. Example forms and example procedures are included.

Jan 1, 1984

By C. B. Manula

This report is volume 7 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design. Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation," and ventilation. This volume of the final report describes the Rail Haulage subsystem of the Master Design Simulator. This subsystem can be used as a free standing model or can be linked to the Production subsystem to provide rail haulage capability. Complex rail haulage systems can be realistically simulated with this model. This report includes complete instructions for operating the subsystem as well as a program listing. In addition, a case study is included which illustrates the application of the subsystem when linked to the production subsystem.

Jan 1, 1974

By W. W. Weller

Heat capacity measurements of anhydrous cobalt sulfate (CoSO4), copper sulfate (CuSO4), nickel sulfate (NiSO4), and zinc sulfate (ZnSO4) were conducted over the temperature range 51° to 298° K. The results were used to evaluate the following entropies at 298.15° K (cal/deg mole): CoSO4, 28.1; CuSO4, 26.8; NiSO4, 24.8; and ZnSO4, 26.4. Entropies were combined with heats of formation to give free energies of formation.

Jan 1, 1965