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By F. S. Boericke

"INTRODUCTION The mineral found in natural-chromite deposits is never pure Fe0.Cr203, but rather one in which the Fe0 and Cr203 are in part replaced by Mg0 and A1203, respectively. The purest gravity concentrates from many domestic de¬posits consist of a mineral referred to as ""picotite,"" in which this isomorphous replacement is such that the ratio of chromium to iron is low. The Bureau of Nines has investigated methods of chemically beneficiating ores that contain too much iron to be classed as ""high-grade"" chromite 3/ Early investigations 4/ demonstrated that high-iron chromite or picotite ores can be roasted with carbon to obtain selective reduction of the contained iron, and that most of this reduced iron can be removed by acid-leaching the roast products to produce residues of higher chromium-to-iron ratios. tests 5/ indicated that commercially acceptable reaction rates cannot be obtained at roasting temperatures below 1,3000 C., using solid carbon as reducing agent. By this high-temperature reduction and subse¬quent acid-leaching, however, all ores investigated, regardless of the original composition, readily yielded residues considerably better than the minimum specifications for high-grade chromite.In an effort to obtain satisfactory reduction of chromite at lower temperatures, liquid and gaseous seducing agents were tested with varying success. Of the several reducing agents used, methane appeared to be the most promising and was shown to be highly effective at temperatures between 1,000º and 1,100º C., roughly 300º below the roasting temperatures necessary in solid carbon reduction. Further experiments indicated that mixtures of methate with some diluent (hydrogen or other nonoxidizing gas) gave better reduction than did methane alone."

Feb 1, 1946

By E. P. Barret

Differences in the reducibility of iron oxide materials have been recognized for a long time. Limonites are deoxidized more readily than hematites, and unaltered magnetites are the most difficult to deoxidize. Sinters are found between hematites and magnetites and vary considerably in reducibility, depending on the sintering practice followed and on the degree of fusion of the product. The increased activity in the beneficiation of taconite recently has made available a new blast-furnace raw material, namely, iron oxide pellets made from magnetic taconite concentrate. Many of the data in this paper apply to these pellets, or glomerules, as they were called when this method of agglomerating iron ores was first considered. To clarify the terms applied to iron oxide materials in this paper, the following definitions are given. Agglomeration is the general term applied to all methods of compacting or consolidating fine iron oxide materials. Sinter is the product from a Dwight-Lloyd or Greenawalt sintering machine. Pellets are formed by balling fine, moist oxide in a rotating drum at room temperature, followed by heating in a shaft furnace to a temperature below that of incipient fusion to develop a permanent bond. Nodules are formed by heating the iron oxide material to incipient fusion in a rotary kiln. Briquets are formed in a mold under pressure, with or without the addition of a binder, and burned to develop a permanent bond.

Jan 1, 1949

By Steven W. Schmauch

The Sugarloaf RARE II area (No. 5296) covers 11,100 acres in the northern part of the White Mountain Range, in the Inyo fictional Forrest. It is in Nevada, about 45 mi north of Bishop, California. A mineral survey was conducted by On U.S. burro of Mines in 1982 and by the U.S. Geological Survey in 1980-1982. The Bureau reviewed pertinent literature, searched Esmeralda and Mineral County mining records, obtained current claim information from the administrative agencies, and contacted claim owners. Thirty-six properties were examined, and 674 samples were taken from them to help assess win oral resources and potential. The Geological Survey evaluated the regional mineral potential by geologic, geochemical, and Geophysical surveys.

Jan 1, 1983

By E. M. Murphy

Comparative data from ASTM method of test E-162 and large-scale trials in the Experimental Mine show that the flame-spread quality of brattice cloth and other ventilation control materials can effectively be evaluated by either method. Materials having a flame spread index of 25 or less, as determined by the simpler and more economical laboratory test ASTM E-162, do not present a serious fire hazard when used in coal mines.

Jan 1, 1972

In 2006, a total of 4,573 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Stone mines comprised 30.7% of all mining operations. ? Mines producing the primary commodity of limestone (crushed and broken) comprised the largest number of operations (n=2,042; 44.7%). ? Stone mining operations were located in all states and territories except Delaware and North Dakota. ? Pennsylvania had the most stone mines (n=368; 8.0%), followed by Texas (n=342; 7.5%).

Jan 1, 2008

Quickly and cheaply consolidate underground slimes to facilitate their use as backfill and permit their easy handling for other reasons. Approach: The slurry containing slimes is pumped into active stopes and electrokinetically dewatered to provide consolidated back fill. How It Works: To densify slimes electro-kinetically two electrodes are placed in the material to be dewatered and densified. Typically, the electrodes are pieces of wire mesh fencing. One is placed on the bottom, and the other is suspended in the slurry near the surface. Figure 1 is a simplified section of a test. A d-c voltage of 100 to 400 volts is applied across the slurry. This causes the solid particles which are in suspension in the water (usually these are negatively charged) to migrate toward the anode; simultaneously, the water moves toward the cathode. Water immediately adjacent to the negatively charged solid particle surfaces contains an excess of dissolved positive ions. When these ions are attracted to the electrode and move towards it, they also exert

Jan 1, 1976

By Andrew M. Leszcykowski

In 1985 at the request of the Bureau of Land Management, personnel from the U.S. Bureau of Mines examined a 27,680-acre portion of the 30,420-acre King Hill Creek Wilderness Study Area (10-19-2) in order to evaluate the mineral resources. The study area, in southwestern Idaho, is underlain by Tertiary tuffs and basalt. There are no known mining claims or prospects in the study area, and no mineral resources were identified. The Volcano mining district is immediately north, but mines there are in granitic rock which does not crop out in the study area. Oil and gas leases were offered for land in the southern part of the area, but no applications were filed, and the lease offering was withdrawn (1985). INTRODUCTION This report describes the USBM (U.S. Bureau of Mines) portion of a cooperative study with the USGS (U.S. Geological Survey) to evaluate mineral resources and potential of the King Hill Creek study area at the request of the BLM (U.S. Bureau of Land Management). The USBM examines individual mines, prospects, claims, and mineralized zones, and evaluates identified mineral and energy resources. The USGS evaluates potential for undiscovered resources based on areal geological, geochemical, and geophysical surveys. Results of the investigations will be used to help determine the suitability of the study area for inclusion into the National Wilderness Preservation System. Although the immediate goal of this and other USBM mineral surveys is to provide data for the President, Congress, government agencies, and the public for land-use decisions, the long-term objective is to ensure the Nation has an adequate and dependable supply of minerals at a reasonable cost.

Jan 1, 1986

By WILLARD W. CUTLER

This bulletin reviews, in the light of recent experience, the use of production-decline curves in estimating the future production of oil from wells. It deals with the estimation of the reserves of recoverable oil in properties already producing or in those adjacent to them, takes cognizance of the physical laws governing expulsion of oil from oil sands, and shows how the production-decline curve can be made to utilize these laws in estimating reserves and rates of production. The valuation of oil properties should be based on the total amount of oil recoverable from a property by the methods in use, the rate of recovery, the cost of production, and the selling price. Numerous other curves besides those for reserves and rates of production may be formed from the production-decline curve and will present desired information in a convenient time-saving form. These curves also are described. Methods developed before the production-decline curve method was used are briefly discussed in order that the principles on which estimations of oil reserves are based may be made plain. The construction of curves and tables for estimating future production of individual wells and of average wells in most of the important oil districts of the United States is described and operating problems that may be solved by the use of production-decline curves are discussed. The bulletin does not deal with costs, oil prices, or the methods of evaluating oil properties. Many engineers have amply demonstrated the value of the production- decline curve method by forecasting within reasonable limits the production of many thousands of wells and tracts. The value of similar estimates depends however, on (1) the application of trustworthy methods; (2) the care and judgment of the estimator; and (3) the length and reliability of the records and the accuracy of ofher information used in estimating future production. When adequate records and information are available, experience has shown that It qualified engineer can forecast production far more accurately than has been deemed possible, except where the usual conditions governing the expulsion of oil from a sand have been radically changed by applying compressed air or by flooding with water, or, to a less degree, by using vacuum. In general, the production-decline curve method, though there are limits to its accuracy, is far more trustworthy than any other.

Jan 1, 1924

By Sheridan J. Rodgers

Toxic fumes generated during shot firing were measured in a phosphate rock mine and a copper mine. Fumes generated during firing of explosives in the Bureau of Mines 1350 ft3 test chamber were measured also. The release of fumes from water gels, ammonium-nitrate oil mixtures and nitroglycerin based explosives was studied. Direct reading instruments were used to monitor the fume concentrations. The amount of CO produced per unit weight of nitroglycerin explosives (0.41 ft3/200 grams) was higher than that produced by ammoniumnitrate-oil mixtures (0.24 ft3/200 grams) and water gels (0.16 ft3/200 grams). The amount of NOx produced by nitroglycerin based explosives was also higher than the amount produced by water gels or ammonium nitrate-oil mixtures.

Jan 1, 1976

By James Gibbs

In order to provide an initial approach to the deposits of oil shale, nahcolite, and dawsonite in the central area or the Piceance Creek Basin in northwestern Colorado, the U.S.B.M. and associated contractor personnel drilled and cased a 96-inch ID shaft to a depth of 2,371 feet. The shaft was constructed using ?big hole? drilling techniques and succeeded in giving access to previously inaccessible deposits of the above minerals. This report documents the construction from its beginning in January 1977 to its completion in January 1978. Procedures used and problems encountered are discussed in detail.

Jan 1, 1978

Real gross national product increased at a larger-than- expected annual rate of 8.3 percent in the first quarter of 1984, with both consumption and investment spending increasing significantly in real terms (table 1). Residential and nonresidential fixed investment increased at annual rates of 25.7 and 14.6 percent during the first quarter of 1984, and investment in nonresidential structures, which declined in 1983, also increased during the first quarter of 1984, nearly attaining its 1982 level. The annual level of personal savings increased $27.7 billion, while the personal savings rate (the ratio of personal savings to disposable income) increased to 5.8 percent during the first quarter. The increase in the personal savings rate comes as welcome news to analysts concerned over the flow of loanable funds to the private sector and the impact on interest rates in 1984 of increased private and Government demands. U.S. Minerals Industry Performance A major upswing in the performance of the metal mining sector occurred during the first quarter of 1984, with production increasing almost 11.2 percent from January to March, The recovery of the metal sector is also reflected in the performance of primary metal industry profits, which were positive during fourth quarter 1983 following seven consecutive quarterly losses (table 1). Two thousand nine hundred more metal mining production workers were employed in February 1984 than in February 1983.

Jan 1, 1984

THE Synthetic Liquid Fuels Act (30 U.S.C., 321-325, and amendments) become law April 5, 1644, 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 a pressure hydrogenation,3 the Fischer-Tropsch synthesis,4 and 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 Hither the Fischer-Tropsch or coal-hydrogenation processes, publishing this sizable, collection of technical information in this form will be valuable. The material is presented in three parts, as follows: I. United States Patents. II. United Kingdom, Australian, Canadian, and South African Patents. III. Belgium, French, German, Italian, and Swedish Patents. The domestic patents for this bulletin were collected between 1963 and 1955. Some of the Foreign Patents were collected at the same time and a few of them later in 1961. Part I was published in 1960; Part II was published in 1962.

Jan 1, 1964

By J. R. Hamke

THE WILLISTON basin is the largest known sedimentary basin on the North. American continent. Two-thirds of this large basin lies within the United States in Montana, North Dakota, and South Dakota. Less than 10 years after the first commercial oil discovery in North Dakota in 1951, the petroleum became one of the largest industries in the three-state area. Crude petroleum is now the most valuable mineral resource in the area. In 1960, the basin produced 39 million barrels of worth $100 million at the wellhead. Most of the 137 oil pools covered to date are in Paleozoic carbonates at depths ranging from 3,000 to 13,000 feet. The major producing fields, centered on the Cedar Creek anticline in Montana and the Nesson anticline in North Dakota, produce from depths below 6,000 feet. This report presents descriptions of all phases of the Williston basin petroleum industry, including leasing, exploration, geology, drilling, production, transportation, and refining. Engineering, physical, and production data, maps, and crude petroleum analyses for 137 separate oil pools are included.

Jan 1, 1966

By E. G. King

Heat of formation values for mercuric sulfide appear in all the comprehensive listings of thermodynamic data, but experimentally determined entropy values have been lacking. Consequently, all free energy calculations involving mercuric sulfide have been based upon estimated entropy values. This paper reports Bureau of Mines measurements of the low-temperature heat capacity of red mercuric sulfide (cinnabar) and the entropy value at 298.15° K. derived therefrom. The entropy value was combined with heat data to obtain free energy values for the formation of red mercuric sulfide from liquid or gaseous mercury and from rhombic or gaseous diatomic sulfur.

Jan 1, 1962

By A. T. Sweet, G. Douglas Gardner

"INTRODUCTION In the ammonium sulfate process for the production of alumina from clay,,3/ the clay is baked with amonium sulfate at about 400ºC. to form anhydrous ammonium alum and free ammonia or ammonium carbonate. The alum is leached from the baked product with water and circulating liquors and is purified by recrystallization. Aluminum hydroxide is precipitated by treating thus alum the alum the ammonia or ammonium carbonate from the baking step. Ammonium sulfate is recovered from the filtrate for reuse, and the aluminum hydroxide precipitate is calcined to produce high-purity alumina. In this process, as in other acid processes for the production of alumina, 4/ a large part of the iron in the clay is extracted. The iron tends to build up in the leach liquors and contaminate the crystals, so that its elimination is one of the most important problems in the process. A number of large clay deposits occur in the Western States. Those that have boon explored most extensively 5/contain an average of 24 to 30 percent available A12O3 and 2 to 8 percent available Fe2O3. 6/ The available Fe2O3 content of various other clays ranges from less than I percent to more than 20 percent. The available Al2O3 or Fe2O3 is usually 90 to 98 percent of the total but may be much less. In generals the iron content bears no fixed relation to the alumina content and may vary widely within a given deposit."

Jan 1, 1948

By Albert Ketler

[Early Bureau of Mines research had produced a fluorescent mine illumination system which was approved by MESA under Schedule 29A for use as portable equipment Intense industry preference for machine-mounted hardware required a MESA 2G approved system. The modifications required to upgrade the portable system arc herein described.]

Jan 1, 1976

By D. V. Keller

Black lung disease, or paeumocomosis, is a serious health hazard for workers working in a coal mine. Though the exact cause of black lung disease is not known, it is certain that prolonged inhalation of fine coal particles, ever present in the mines, does give rise to black lung disease. For a long time, it also has been known that limestone applied to coal dust mine surfaces tends to hold down coal dust thus preventing it from refloating in the air of the coal mines. Since the humidity in the mines may be generally high, this also might be an important factor in the particular substrate system behavior. Fine solid particles stick to other particles and surfaces very indiscriminately. The term adhesion is used for the phenomenon of attachment of particles to surfaces whereas cohesion is used for the phenomenon of attachment of particles to each other. The measurement of the force of adhesion of coal particles to coal substrates presents a great problem, especially in the case of particles in the size range of a few microns. These micron sized particles are at the limit of the resolution of the optical microscope and therefore an electron microscope has to be used for this purpose. The forces of adhesion between these particles and substrate may be very strong and can exceed the weight of the particle by four to five orders of magnitude.

Jan 1, 1973

By Wadaw Cybulski

The problem of coal dust explosions: Basic information about the explicability of coal dust: Main parameters of the explosibility of coal dust; Main parameters of the explosibility of coal dust; Limit explosibility of coal dust and its dependence upon the basic parameters: The effect of the initiator of the explosion-on-the explosibility of coal dust: The dependence of the course of an explosion upon the distribution of coal dust in the workings, upon the dimensions of the workings, the length of zones, the direction of the development of explosions and upon the content of firedamp in the air of the workings; Con-sequences of coal dust explosions; The ways of suppressing the danger of coal dust explosions; Stopping the developed coal dust explosions; The explosibility and explosions of lignite dust of xylite structure

Jan 1, 1975

By Guthrie. R. K., H. B. Hill

"INTRODUCTION During the early 1920's world-wide attention was attracted to a group of oil fields (Mexia, Wortham, Currie, Richard, and Powell) later known as Mexia-Powell fault-line fields in Limestone, Freestonne, and Navarro Counties, Tex. Enormous yields of high-gravity oil from the wells in these fields resulted in drilling campaigns that quickly surpassed all previous records for rapid, intensive development of productive areas. The discovery of oil in the Mexia filed in September 1921 was followed quickly by the finding of oil in the Currie field in October. In January 1923 oil was discovered in the Powell field; in February 1924 the Richland field, midway between Currie and Powell fields, was brought in; and in November 1924 oil was discovered in the Wortham field, situated between Mexia and Currie fields. Each of the fileds was developed rapidly: wells were spaced closely and had high initial production; production peaks were reached early in the producing lives of the fields; subsequent decline was rapid, and there was early and rapid encroachment of edge water.In 1927 Bureau of Mines engineers, in their investigations a engineering conditions in oil,completed a preliminary study and published a mimeographed report 4/ on underground conditions in the Wortham field, and in 1928 they reported on production and development problems in the Powell Field. 5/ field."

Aug 1, 1943

By G. T. Lineberry, W. J. Wiehagen

A Paradigm Shift As market economists, mine managers are interested in "staying in business" and even "prospering." Bottom-line results are the "order of the day." Concern for bottom-line results invokes questions such as: How much was produced? At what cost? And, was anyone injured? While these questions will always carry everyday emphasis at the mine, they are fundamentally lacking in that they often appear, especially to lower levels of management and to the production worker, as preeminent concerns. Driven by market economics, many organizations have decentralized, outsourced, downsized, restructured, and formed new coalitions. Investments in new technology and concentration on productivity have been part and parcel with these changes, contributing to improvements in both safety and efficiency. A reason for (and, perhaps a result of) these improvements has been the development of a highly experienced and flexible work force. These changes in mining present an interesting opportunity to modify a few paradigms about work life in general, and perhaps a few paradigms about how we invest in the miner, in particular. Studying these issues now might offer some interesting opportunities for the future, as the foundations for the next generation of mine workers are laid. With the average "experienced" U.S. miner five to fifteen years from retirement, perhaps a key determinant of future success in the world market might be how well we make the transition from today's work force to the work force of tomorrow. We can ill afford to wait a few more years to tap into the special knowledge residing within a veteran mining work force. The WCPM work Crew Performance Model, see pp. ) is one approach to defining, capturing, and transferring this expertise.