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By John H. Weitz

Dolomite, heretofore regarded merely as a variety of commonplace limestone, has suddenly attained headline prominence, partly because of the increase in demand for dolomite refractories to line metallurgical furnaces now working at an unprecedented rate of activity, but chiefly because it has become an ore of the light-weight metal, magnesium, needed in vast quantities for the manufacture of war machines. A multitude of inquiries, chiefly from war agencies and prespective operators, for data not only on locations of dolomite deposits but on their size and quality, has made it necessary for the Bureau of Mines to assemble all information available on this important subject. From the Bureau's own records, published information, and correspondence, date on locutions, extent, thickness, accessibility, workability, and chemical composition of high-grade dolomite deposits throughout the United states were accumulated for presentation herein. The report includes about 1,000 tabulations of analyses and a map showing locations of the deposits. The uses of dolomite are discussed in Bureau of Mines Information Circular 7192, "Occurrences and Uses of Dolomite in the United-States," published in 1941. The cordial corporation of many State ecological surveys and various individuals who have contributed information is gratefully acknowledged.

Jan 1, 1942

This three-part report provides the results of an industrial engineering study that assessed the safety and efficiency of underground ore handling in U.S. metal mines. One of the primary findings of the study was the improvement needed in controlling muck size in the are handling stream. Oversize ore is causing much additional labor, creating work stoppages, and is a principal cause of accidents in metal mines. The specific objectives of the Present Systems Study were to determine and evaluate the productivity of existing ore handling systems in a representative group of underground metal mines, to relate the available historical accident record statistics of these selected mines to the specific operations in the overall ore handling operations, and to highlight the potential areas of improvement for each mine on the basis of productivity and associated hazardous index for each operation.

Jan 1, 1974

On 26 August 1971, the Bureau of Mines, through the Spokane Mining Research Center at Spokane, Washington, approved initiation of the evaluation of oscillatory energy toward enhancing flow of polymer into shale. The effort was an outgrowth of work performed under Bureau of Mines Contract H0210055, "Feasibility Study of Surface Impregnation equipment for the Chemical Stabilization of Coal Mine Structures," wherein feasibility of the impregnation concept was expressed and the detailed design of a machine for impregnation of coal mine roofs with polymer (under static pressure head) accomplished. Under these efforts, the potential enhance¬ment of polymer uptake into the shale thru superposition of oscillatory energy on the static impregnation pressure was suggested. A proposal for investigation of this phenomena entitled "Feasibility Study of the Application of Oscillatory Energy as an Aid to Afford Chemical Stabilization" was presented to the Bureau whereupon a three month program for initiation of investigation was approved.

Jan 1, 1972

By Seth C. Scharfer

"As part of the Bureau of Mines effort to provide thermodynamic data for the advancement of mineral technology, the Gibbs energies of formation of MoS2 (molybdenite) and WS2 (tungsten disulfide) were determined with high-temperature galvanic cells employing stabilized Zr02 (zirconia) as the electro¬lyte. In the temperature range from 867 to 1,209 K, potential measurements were obtained for the cellPt, MoS2 , Mo02 , SO2 = 1 atm // Zr02 // 02 = 0.0112 atm, Pt, with the overall cell reactionMoS2(c) + 3 02(g, 0.0112 atm) = Mo02 (c) + 2 S02(g). (1)These results, combined with the best available values for Gibbs energies of formation (?G°f) of Mo02 (molybdenum dioxide) and SO2 (sulfur dioxide) from the literature, give the standard Gibbs energy of formation of MoS2, ?G°f, for the reactionMo(c) + S2(g) = MoS2(c) (2)?G°f = -96.681 + 43.76 x 10-3T±0.538 kcal/mole, (3)where temperature (T) is expressed in Kelvins.Similar measurements in the temperature range from 872 to 1,210 K were obtained for the cellPt, WS2 , W03 , SO2 = 1 atm // Zr02 // 02 = 0.0114 atm, Pt, with the overall cell reactionWS2(c) + 3.5 02(g, 0.0114 atm) = W03 (c)+ 2 S02(g). (4) Combination of these results with the best available data of ?G°f for W03 (tungsten trioxide) and SO2 from the literature gives the Gibbs energy of formation of WS2 in the temperature range from 872 to 1,210 K for the reactionW(c) + S2(g) = WS2 (c)(5)?G°f = -92.429 + 43.88 x 10-3T ± 0.280 kcal/mole. (6)A third-law analysis yields a standard enthalpy (?H°f) for the reaction298Mo(c) + 2 S(rh) = MoS2(c), (7)?H°f = -67.36±0.60 kcal/mole, (8)298where the standard states are pure crystalline MoS2 / and rhombic sulfur."

Jan 1, 1980

By A. Galibois, M. Fiset, T. Vo Van

"RÉSUMÉUn groupe de 22 objets prov enant des Forges du St-Maurice a été étudié de façon systématique par analyse chimique et examen métallographique afin de préciser leurs caractéristiques et d'en évaluer la qualité métallurgique.La plupart des échantillons de fe r forgé et d'acier sont hétérogènes tant au niveau structural que composition chimique. L'examen de quelques produits fin is a mont ré qu 'on appliquait des traitements superficiels bien que le contrôle métallurgique fût plutôt empirique.AbstractA group of 22 specimens originating from ""Les Forges du St Maurice"" has been systematically studied by chemical analysis and metallographic examination in order to determine their characteristics and to evaluate their metallurgical quality.The bulk of the forged iron and steel samples are heterogeneous from both their microstructure and their chemical composition. Observation of a few finish products has permitted to establish that surface heat treating was applied although its metallurgical control was rather empirical."

Jan 1, 1984

By R Hall

Subduction zone magmatism is a direct response to tectonic and chemical processes operating at convergent margins. Changes in the tectonic configuration of plate boundaries in SE Asia during the Cenozoic had consequences for the nature and volume of magma produced. Retreat or advance of the trench hinge has probably been an important process in controlling the presence or absence of magmatism in SE Asian subduction zones. This process also provides a means of replenishing the mantle wedge and counteracting the effects of melt extraction in depleting the wedge. Changes in the nature of recycled material and lithologies of the over-riding plate also have the potential to influence the lavas that are erupted in arcs. Several locations in SE Asia have experienced magmatism bearing the geochemical signature of subduction but are remote from coeval subduction zones. Such magmatism requires an earlier period of mantle enrichment by subduction but may result from localised extension. The distribution of such magmatism may provide information of tectonic value. Some adakitic magmatism occurred in tectonic settings where there is no evidence for subduction of young oceanic crust at the time of magma genesis. Slab melting in such settings is not possible and alternative mechanisms are required to explain the occurrence of, at least some, adakitic lavas.

Jan 1, 1999

By John Meuth, Brandon Fryman, P. E. Hoffman, Joshua Ph. D., P. E. Calnan, Josh Ph. D.

Quantitative Risk Assessment (QRA) can be specifically tailored for use by the commercial explosives industry to calculate risk to employees and the public from commercial explosives facilities and operations. This methodology has several advantages over the American Table of Distances (ATD) which is solely a Quantity Distance (Q/D) analysis. While the ATD has remained essentially the same for 100 years, the safety of commercial explosives in storage has increased immensely. However, the concepts behind QRA calculations are not as intuitive and even at the end of the calculations the values of risk must be compared to something. A few regimes for assessing an acceptable level of risk are discussed in this paper. Risk levels for various United States Federal entities and international agencies are highlighted and suggestions for acceptable risk criteria for individuals and groups are provided. Referencing risk levels from normal daily activities is also done in this paper to make relative the accepted risk criteria. This paper presents some relevant individual risks for everyday activities and some scenarios for group risk for comparison. Individual risk is a straightforward concept however group risk is more complicated. This paper aims to clarify these concepts and provide means to communicate them to the public.

Jan 1, 2019

Reverse Cationic Flotation of Iron Ores - Floatability of Amphiboles at Depression of Iron Oxides by Starch

Sep 13, 2010

By Barbara Hendrickson

Outline ? Canadian Regulatory Update ? Turning the Corner: Background & Status ? Implications of U.S. Waxman-Markey bill for Canada ? Federal-provincial considerations ? Current certainties and uncertainties ?Turning the Corner? as Originally Proposed ? April 26, 2007 - the Canadian federal government announced Turning the Corner: An Action Plan to Reduce Greenhouse Gases and Air Pollution (?Turning the Corner?)

May 1, 2009

An Investigation into the Flotation Behaviour of Pyrrhotite Present in the Merensky Orebody

Sep 13, 2010

By Edward Keller

The work covered by this report was undertaken at the request of Dr. J. A. Holmes, late Director of the Bureau of Mines, to whom the writer had been recommended by C. W. Goodale and E. P. Mathewson, of Butte and Anaconda, Mont. The director's offer was accepted for the honor it conferred and for the useful results that might be promulgated by the work in the technical field covered. The investigation was facilitated by permission to visit various works and sometimes by contributions of important definite information on a given subject. It is therefore with pleasure that acknowledgment of courtesies is made to the following corporations and gentlemen: Anaconda Copper Mining Co., Raritan Copper Works, Baltimore Copper Smelting & Rolling Co., United States Refining Co., American Smelting & Refining Co., B. B. Thayer, A. C. Clark, A. L. Walker, William H. Peirce, E. A. Cappelen Smith, H. H. Alexander, F. C. Newton, S. Rolle, R. "V. Deacon, N. W. Pierce, O. C. Martin, C. N. Sappington, James K Thomson, W. G. Derby, and the assistants of the writer, K. 1V.McComas and W. L. Raup. In this report considerable space has been devoted to general and theoretical principles on the ground that under modern conditions the best results in any field of activity can be attained only with the aid of an adequate knowledge of the best theories underlying the practice. The diffusion of such knowledge in the field of sampling metallic metallurgical materials appears to have been quite insufficient, and it is felt that when the principles involved are once thoroughly comprehended their universal application will be appreciated, so that it will make no difference whether pig iron or gold bullion is offered for test. It may further be noted that a discussion of the theories underlying practical methods is placed under the caption "Practical Sampling," with the idea that no one can be a practical sampler unless he is capable of analyzing his methods. No attempt has been made to advocate anyone method, but it is hoped that the analyses of all of the methods in use will show where each may be correctly and safely applied. The fact that it is possible to demonstrate the theoretical correctness of several methods indicates the invalidity of the claim that any single one of them is the standard.

Jan 1, 1916

By W. A. Calhoun, M. M. Fine

"One of the most important wartime activities of the Bureau of Mines was the search for new sources of mineral necessary to the prosecution of the war. Part of that effort was in the form of metallurgical service extended to other government agencies engaged in purchasing and stock piling some of the more critical and strategic materials.Fluorite was one of the materials stock piled by the Metals Reserve Company. The fluorite was usually in the form of coarse metallurgical con¬centrate purchased in the United States and abroad. The material was stock¬piled to insure an adequate reserve of fluorite for the metallurgical industries. The domestic production of metallurgical fluorite containing a minimum effective calcium fluoride content of 55 percent,4/ however, gradually increased until production was at least equal to consumption. The stock-piled metallurgical fluorite, therefore, soon became a surplus commodity.On the other hand, the supply of acid-grade fluorite, containing a minimum of 97.5 percent calcium fluoride and n maximum of 1.5 percent silica,5/ was never entirely adequate. Increased consumption of acid-grade material in the aluminum, petroleum, and chemical industries kept that material on the critical list during the war.Under the circumstances, it was felt that a study of the possibility of producing acid-grade fluorite from the metallurgical stock piles would be of some benefit to the war effort. Consequently, samples of fluorite from several of the Metals Reserve Company stock piles were tested by the Bureau of Mines at the request of the War Production Board.Two groups of samples were submitted for testing. One consisted of metallurgical fluorite purchased from Mexico and stock-piled in the El Paso and Laredo, Texas, stock piles of the Metals Reserve Company. The second group of samples was from the stock piles at Gila, N. Mex.The sample submitted from the El Paso stock pile consisted of about 5,000 pounds of minus 4-inch material. Mineralogically, the sample consisted of fluorite contaminated by calcite, chert, quartz, and small amounts of iron and alumina. Although some of the fluorite was reasonably free from gangue at minus 1-inch, much of it remained locked in sizes as fine as 65-mesh.The Laredo sample was about 5,000 pounds of material from five different piles. The samples from each stock pile, A to E, inclusive, were analyzed separately to determine whether the grade of the material in the piles varied markedly. As there was little difference in the analyses, the samples were combined in proportion to the tonnage represented to make a composite sample for testing. The composite sample consisted of fluorite with small amounts of quartz, calcite, and barite. Most of the fluorite was the dark-colored, opaque variety. A small amount of iron-oxide staining was present, and traces of muscovite, clay, pyrite, and tourmaline were noted. The quartz was present as crystals in vugs, and as finely disseminated grains in the fluorite. The druzy quartz and the calcite were free at minus 10-mesh, but the disseminated grains, some of which were 1 to 15 microns in size, were not entirely free at minus 270-mesh. A petrographic estimate indicated that 65 percent of the silica was locked in the 150- to 200-mesh."

Jun 1, 1946

By Richard S. Dennis

Acid recovery employs ion exchange (I-X) resin as separation media for inorganic acids from dissolved metallic salts by physical adsorption and without the use of chemicals. This technology has been used for years on spent etching and plating liquors to recover acid for reuse in the bath and to reduce waste acid neutralization costs. It is also used for electrolyte treatment to facilitate valuable metal recovery via acidity reduction. TETRA's ccrxr'" I-X contactor has been used successfully for acid separation from its metallic salt counterpart in a simple, continuous operating mode using strong base anion resins. Efficient separation is enhanced by acid reconcentration to nearly its original strength or as high as 14-20%. Continuous treatment also recovers heat to the tankhouse or bath and improves metal quality due to consistent acid quality. Conventional fixed bed ion exchange (I-X) systems are impractical for acid recovery because of complex control design and large resin inventories needed to process very low liquid-to-resin treatment ratios associated with strong acid concentrations.

Jan 1, 1996

By Robert T. MacMillan

An essentially chemical technique has been developed on a small scale for the efficient utilization of certain domestic titaniferous iron ores. Three main steps are involved: (1) Sintering the ore at 1,050° C. with carbon and soda ash to reduce the iron to metal powder, retaining the titania in the slag, (2) separating the powdered iron from the slag, after wet grinding, by magnetic or gravity methods, and (3) sulfuric-acid decomposition of the titania fraction to produce pigment and certain byproducts. The technique was first applied to the tailings from the Bureau of Mines bauxite-concentrating plant at Bauxite, Ark. A good grade of powdered iron was produced from this material. Subsequently, the work was diverted to the study of the titaniferous magnetite from the MacIntyre Mine at Tahawus, N.Y., because of the potentially higher recoveries of iron, titanium and vanadium. Ninety percent of the iron in this ore has been recovered as an iron powder analyzing 90 percent metallic iron and containing 2 to 3 percent TiO2. The remaining titania was found in the slag and was recovered as pigment-grade TiO2 by application of a suitable technique. The vanadium was distributed between the TiO2 fraction and the alkaline liquor resulting from the wet-grinding and magnetic-separation operations, with only a minor proportion retained by the metallic iron.

Jan 1, 1950

Lower Miocene Maryville Coal Measures at Waitewhena Coalfield, in the Taranaki coal region, include seams of sub-bituminous coal up to 4 m thick. During coalfield exploration Fletcher Challenge Ltd drilled ten cored holes, all of which encountered at least one seam. Coal quality is variable. Ash ranges from six to 12 per cent and sulphur from 0.5 to three per cent. A basal seam, overlying the Lower Mokau Sandstone, appears to extend throughout the area under investigation. A rider seam, of variable thickness, closely overlies the main seam in most drillholes. The rider converges with the main seam to the north and vertical trends in coal properties suggest that the seams are united in some locations. A less extensive seam sometimes occurs at the top of the coal measures beneath the Upper Mokau Sandstone. The lithostratigraphy of the intervening coal measures is complex, and coexistence of fluviodeltaic, lagoonal/lacustrine, and marine depositional environments is provisionally inferred. Lateral variations in coal properties (clastic derived ash, volatile matter, inertinite, hydrogen), thickness of the sedimentary parting between the basal seam and rider, texture of the coal measure sediments, and distribution of the upper seam all indicate persistence of a relatively low lying northeast-trending zone which may have been structurally controlled. Available data indicate that coal measure accumulation was terminated by marine transgression from north to south.

Jan 1, 1987

By A. T. Iannacchione

The Bureau of Mines established geologic factors affecting the mining of the Lower Kittanning coalbed to aid in coalbed minability studies and examined the occurrence of "wants" (places where coal is missing) and types of unstable roof rock strata. Trends established from mapping, including prediction of areas of high methane emissions, were extrapolated to unmined areas. 'Wants' in the coalbed are of two types: Erosional and depositional. Erosional features occur where north-south-trending sand-filled channels cut into the coalbed. Variations in depositional environments have caused the coalbed to "split" into several thinner units. Slickensides, commonly indicative of unstable roof, are adjacent to and on the underside of sandstone channels; they were caused by differential compaction and by soft sediment sliding along the contact between the sandstone and adjacent shale. The frequency of unstable roof also increases where the interval between the Middle and Lower Kittanning coalbed is less than 30 feet. The zones of weakness at the contacts above and below the Middle Kittanning coalbed are the controlling factors for unstable roof in these strata. Methane emissions from the coalbed are controlled primarily by depth, fracture permeability, and rank of coal. Local geologic factors are coalbed thickness, associated rock strata, structure, and proximity to outcrop.

Jan 1, 1979

By C. H. Riggs

This report describes the development, oil recovery, and potentialities of productive formations in the Hall-Gurney field, Russell County, Kans. It is presented as part of a general program to aid and promote increased recovery from petroleum reservoirs. The report is based on studies of well logs, drill cuttings, and oil-and water-production histories of individual wells and leases. The geological interpretations follow closely those in published literature with only slight local modifications. Oil and water analyses, made at a Bureau of Mines research center, were supplemented by many analyses obtained from oil-producing and service companies. The Hall-Gurney field, in south central Russell County, Kans., (fig. 1) was discovered in 1931 but was not developed extensively until 1941. By 1960 the rate of oil production from the field had declined to the extent that many wells were abandoned. In some areas natural productive forces have effected good recovery. However, in other areas inefficient waterflooding, both natural and accidental, has adversely affected recovery potentialities.

Jan 1, 1963

By T. Tamagawa

A gaseous chlorination process for hydrometallurgical treatment of a chalcopyrite concentrate was investigated. The overall process is visualized to consist of low temperature chlorination-selective oxidation, followed by aqueous chloride leaching and SX-EW for producing electrolytic copper elemental sulfur and ferric oxide. In this article, the chlorination phase of the processes is described. Initially, the chlorination behavior of chalcopyrite-concentrate micro-pellets was investigated using a small batch-type fluidized bed reactor. The optimum conditions thereby established was used in continuous chlorination tests. The chlorinated products thus prepared were used in the selective oxidation phase of the investigation.

Jan 1, 1999

Removal of Arsenic in Fluorite Ore by Simultaneous Grinding-Leaching with NaHS Generally speaking, a high-grade fluorite ore is converted into hydrogen fluoride (HF), which is essential for the semiconductor manufacturing. With the continuous depletion of resources, novel technologies for processing low-grade fluorite ores are urgently needed, in order to lower the arsenic concentration to less than 100 mg/kg. In this study, a low-grade fluorite ore was upgraded by removing arsenic, which is difficult to remove by conventional method. The mechano-chemical leaching of fluorite ore (i.e. the sample was ground in presence of NaHS, using a beads mill) was carried out to investigate the removal of arsenic from the low-grade fluorite. Experimental results showed that the arsenic concentration was reduced to 73.2 mg/kg.

Sep 13, 2010

By A Tawadrous, P D. Katsabanis, S Kim

A series of small scale tests, have been performed to establish the effect of powder factor and initiation timing on the grindability of rocks. The blasts were performed in high quality granite blocks, which were cut from stone prepared by dimensional stone quarry operations. Three different types of granite, Barre, Stanstead and Laurentian, were tested. The charge consisted of detonating cord placed in five holes with water as a coupling medium, or concentrated charges of equal mass of high exolosive, fully stemmed or air decked. Powder factor was varied from 0.39 to 1.17 kg/m3. Charges were detonated simultaneously or with a small delay and in some experiments, detonation waves collided in the middle of each borehole. All fragments were collected and screened, and drop weight impact tests were performed on selected size fractions, using different levels of impact energy, to calculate the resistance of the rock to impact breakage. The work index of some of the blasted samples was measured using standard Bond mill grindability tests. The experiments generally showed increased softening of the rock with powder factor, manifested by the increasing initial slope of the relationship between t10 and impact energy. The rate of change of the initial slope decreased with increasing powder factor. Changes in the work index were small and consistent in trend with the results of the single fragment impact characterization tests. Charge configuration, timing as well as in-hole collisions of detonation waves affected the initial fragmentation but had little effect on the impact breakage of the samples.

Jan 1, 2009