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By Lester J. Crow

A preliminary survey was performed to investigate the impregnation of relatively weak, porous volcanic tuff and a relatively strong, dense sandstone with five different monomers. Increases in compressive strengths by factors of 2 to 5, and elastic moduli by factors of 2 to 3.5, are reported for natural rocks (tuff., sandstone, dacite), which were impregnated with five monomers (methyl methacrylate; chlorostyrene; 40 percent TMPTMA-60 percent styrene; 40 percent TMPTMA-60 percent chlorostyrene; 60 percent polyester-40 percent styrene); polymerization took place after monomers were forced into the rock. Impregnation was performed (1) by pressurizing rock specimens from one end, or (2) by a vacuum-soak operation. Polymerization was accomplished by either radiation or chemical initiation techniques. Strength improvement is dependent on (1) the type of monomer used, (2) the amount of polymer incorporated into the rock, and (3) the degree of water saturation of the rock. Water saturation strongly reduced the effectiveness of the method for the polymer systems tested. The more viscous monomers (for example, 60 percent polyester-40 percent styrene) were more effective in displacing the water from the rock, and compressive strengths of wet rock were doubled with these systems. Water saturations ranging from 25 to 100 percent of maximum saturation gave essentially identical results. Further tests on other types of mine rock; including shale and coal, are planned. Water-compatible polymer systems should be developed, or present systems should be suitably modified. For application to tunnel stabilization, design studies evaluating the improvement in rock strength and its influence on the support system are also recommended.

Jan 1, 1971

By C. M. Harrer

Reconnaissance investigations were made of 129 iron occurrences in Arizona to determine their extent, attitude, and potential; character samples were analyzed to determine their quality and impurities; and pioneer metallurgical investigations were made on character samples to present their metallurgical problems. Some factors influencing past and potential western iron markets are discussed. The location, features, qualities, extent, and potential of iron occurrences and some associative resources--limestone and dolomite, coal, petroleum and natural gas, power, and water are discussed. The most abundant iron minerals are magnetite and hematite. The higher grade deposits are extensive contact-metamorphic or pyrometasomatic replacements of calcareous Paleozoic to Proterozoic rocks associated with intrusives. Large low-grade deposits of great potential are present as Precambrian taconite, semitaconite-, and jaspilite-like iron formations of magnetite-hematite. Iron occurs also as low-grade concentrations of magnetite in extensive alluvial deposits. Nonferrous metallurgical slags, nearly 100 million tons, are considered a potential source of iron. Various accessory elements are associated with the iron minerals and these pose metallurgical and economic problems.

Jan 1, 1964

By C. M. Harrer

Reconnaissance investigations were made of 129 iron occurrences in Arizona to determine their extent, attitude, and potential; character samples were analyzed to determine their quality and impurities; and pioneer metallurgical investigations were made on character samples to present their metallurgical problems. Some factors influencing past and potential western iron markets are discussed. The location, features, qualities, extent, and potential of iron occurrences and some associative resources--limestone and dolomite, coal, petroleum and natural gas, power, and water are discussed. The most abundant iron minerals are magnetite and hematite. The higher grade deposits are extensive contact-metamorphic or pyrometasomatic replacements of calcareous Paleozoic to Proterozoic rocks associated with intrusives. Large low-grade deposits of great potential are present as Precambrian taconite, semitaconite-, and jaspilite-like iron formations of magnetite-hematite. Iron occurs also as low-grade concentrations of magnetite in extensive alluvial deposits. Nonferrous metallurgical slags, nearly 100 million tons, are considered a potential source of iron. Various accessory elements are associated with the iron minerals and these pose metallurgical and economic problems.

Jan 1, 1964

By Alfred R. Powell

In another paper the writer has described an investigation in which the forms of sulphur in coke were determined and described. Coke was found to contain four characteristic forms of sulphur- namely, ferrous sulphide, sulphates, ad- sorbed free sulphur, and sulphur held in solid solution in the carbon. While the coke is still in the oven, only two forms of sulphur are present namely, the ferrous sulphide and the sulphur in solid solution in the carbon. During the quenching, however, the sulphur of the coke is subjected to considerable oxidation, a portion of the ferrous sulphide being oxidized to free sulphur and sulphates, while the solid solution form remains unchanged. The coke, however, loses no sulphur during this process, since the free sulphur which is formed ie retained by the coke in an adsorbed form. Since this oxidation of the ferrous sulphide took place so easily, an inves- tigation was undertaken to determine whether this property could not be taken ad- vantage of in some industrial process for the desulphurization of coke. Although it is true that such a roasting process would not touch the solid-solution form of sul- phur, still the removal of the ferrous sulphide sulphur would undoubtedly benefit the coke from the standpoint of the metallurgist. This improvement in the coke would result not only from the decrease in total sulphur, but also from the large decrease in the ferrous sulphide, which is responsible for the contamination of the iron in the upper part of the blast-furnace. The de sulphurization of coke by roasting in air it a new idea, but dates back to the earliest days of coke manufacture. In 1871, Philipparts published the results of some work done by him on the de sulphurization of coke by air, as well as a review of the results of earlier investigators. In the se earlier experiments, nothing was known of the forms in which the sulphur existed in the coke, while the temperature measurements were only approximate, so that altogether the results were not very conclusive nor complete. The de sulphurisation figures given by the se early investigators generally showed a low efficiency for the process, but some extraordinary results were claimed by certain inventors. In the light of our new knowledge concerning the coke sulphur, it seemed to be important enough to warrant investigation.

Apr 1, 1923

By W. S. Landers

This report presents a study by the Federal Bureau of Mines of technical factors related to the production of special carbon and tar from selected Wyoming coals. Certain Wyoming high-volatile bituminous and subbituminous coals were processed in bench-scale apparatus to determine potential carbonization yields and in pilot plant retorts to produce sufficient char and tar for testing. These tests have shown that a critical selection of coal is necessary when the coal is processed for a specialized carbon. Generally high yields of tar are obtained from low-temperature carbonization of Wyoming high-volatile bituminous and subbituminous coals, and the yield of tar usually increases with increase in rank within this range of coals. The production and evaluation of industrial carbons from Wyoming coals by using pilot plant and bench-scale techniques is part of the continuous program of upgrading western coals. It has been found that: 1. Most Wyoming coals are nonagglomerating and may be carbonized in fluidized systems. Chars produced in pilot plant retorts at low temperatures contain about 17 to 23 pct, residual volatile matter and are easily ignited. These chars appear suitable as power plant fuel. The tar-plus-light-oil yields range from 14 to 40 gal./ton of raw coal processed. 2. Wyoming high-volatile coals produce a slightly smaller and somewhat weaker coke than currently mined Western United States high-volatile coals used commercially as blending stock in metallurgical coke production.

Jan 1, 1961

By D. Harrington, W. J. Fene, H. B. Humphrey

In the fiscal years 1946 and 1947 the number of mine explosions decreased compared with the preceding years. However, the loss of life was so serious during the fiscal year 1947 the period when the Government administered bi- tuminous-coal and lignite mines that from April to June 1947 extraordinary measures were taken in mines then under Government possession to obtain com- pliance with provisions concerning rock dusting, ventilation, and blasting that had not been followed. The great loss of life in explosions during the fiscal year 1947 as compared with 1944, 1945, and 1946 is not easy to explain, but the necessity for maintaining adequate protection has been definitely demonstrated. Management, workers, and inspection agencies alike must keep the mines reasonably safe against explosions or allow them to lapse into a condition where chance is the principal protection against disaster. The at- tention given to protecting coal mines and the men employed in them against mine fires, following the disastrous fires in 1944 and 1945, has at least tem- porarily controlled this hazard loss of life from coal-mine fires was re- duced to 1 fatality in 1947. The number of fires was also less, and progress has been made in reducing the heavy losses in both life and property from un- derground coal-mine fires that occurred in the two years mentioned. Fatalities from mine explosions during the past 6 fiscal years, July 1942 to June 1947, totaled 674, and there were 149 explosions; during the preceding 6 years there were 655 fatalities in 132 explosions. The 6 fiscal years 1942- 47 cover the active period of Federal coal-mine inspection. During the fiscal year 1947, there were 154 fatalities from explosions compared with 58 during the fiscal year 1946, 64 in 1945, 94 in 1944, 152 in 1943, and 152 in 1942.

May 1, 1948

By R. F. Abernethy

Recent investigations in the United States and in other countries have produced considerable information on the nature and occurrence of minor elements in coal. The possibility of recovering certain elements, particularly germanium and uranium, from coal ash and other coal products has received considerable attention. Some flue dusts are potential sources of germanium, and certain lignite deposits are potential sources of uranium, but industrial recovery of these elements has been limited to small quantities for technical and economic reasons. Considering the large amount of coal mined annually, a small percentage of a rare element may have industrial significance if an economical method of recovery can be developed. In 1944 information on the occurrence of rare elements in coal was reviewed in Bureau of Mines Technical Paper 669 (46).3 This report is a revision of that paper with the view of summarizing published information available for United States coals, and pertinent information concerning coals of other countries. Selected references from the original paper are retained. New references do not include all preliminary reports when more permanent literature describing complete projects is available. Consequently, the list of references should not be considered complete.

Jan 1, 1963

By R. J. Leary

This investigation was conducted to determine the effects of various rare-earth metal addition practices upon the macrostructure and the pattern of sulfur distribution in steel ingots. Heats of plain carbon steel were melted in a 1-ton, basic electric-arc furnace. Melts were treated with mixtures of rare-earth silicides, aluminum, and cryolite either in the furnace before tap or in the ladle after tap to determine the effects of this form of rare-earth treatment upon ingot macrostructure. Steels thus treated with rare earths in the furnace were characteristically free of the gross subsurface nonmetallics which typically result from conventional rare-earth treatments. Steel treated in the ladle showed only a few such nonmetallics, and practical techniques were developed for eliminating most of these. Results showed that furnace deoxidation was controlled by the concentration ratio of rare earths: aluminum. During casting, deoxidation was controlled by the concentration of rare earths. Oxygen contents equivalent to vacuum ladle degassing resulted from air-melt furnace treatments with the rare-earth mixtures described. Rare earths in steel inhibited the onset of equiaxed grain formation during ingot freezing, and also virtually prevented interdendritic segregation of sulfides.

Jan 1, 1968

By Scott Turner

Within recent years , people have begun to realize the importance and significance of the mining and allied industries . The leading part the engineer plays in civilization is becoming recognized . However , accurate quantitative knowledge of the industrial importance of mining is still seldom possessed except by those close to this business . It is true that there are a few who go to the extreme and represent the whole progress of civilization as a reflection of man's gradual mastery of mineral utilization , but on the whole , the magnitude of the industry is underestimated . The uncertainties of mining , as evidenced by the variable results of prospecting on surface or underground , in an unknown new field or from the bottom levels of a mature mine , the ins and outs of tonnages and metal contents , the possibility of a widespread or even a sudden change between cost and realization-price , add to its picturesqueness and make mining attractive to some . To many , the fact that results are generally more uncertain and less predictable than in other industries lends added charm . The following pages may serve to call attention briefly to the importance of mining relative to other industries in the United States , in Canada , and in the world . Ordinarily , the annual primary mineral production of the United States amounts to about 5 billion dollars . The average for the last five years has been a little over 5 billion dollars . Last year , sadly enough , it was less than 34 billions . Just now , we are on the decline , and have been for the past two years . In Canada , the 5-year average was about 268 million dollars . Last year it was 227 million . Due in part to gold output ( in 1930 , for the first time , Canada's gold production exceeded that of the United States ) , the Canadian average is holding up better than ours . It has been estimated that the average world mineral production over the past five years has amounted to about 12 billion dollars , while in 1931 it was less than 8 billions . The mineral industries are as indispensable for the conduct of modern society as are those of agriculture , but , in the United States at least , they receive far less recognition from the Government . With us , agriculture is fostered by a great department that is maintained by enormous appropriations , while the mineral industries get but little financial support . In the United States , in the calendar year 1930 , the value of production by these two industries were as follows : to 1 . Agriculture ( inclusive of forestry ) 9.9 billion dollars ; mining 4.8 billions ; ratio 2 Direct appropriations by our Federal Government were 109 million dollars to agriculture and 2.8 million to mining , a ratio of 39 to 1. Obviously this is out of balance to the extent of 19 to 1 in favor of agriculture .

Jun 1, 1932

By D. G. Foot

The Bureau of Mines investigated energy-efficient methods for recovering potash values from process and waste brines. Laboratory pan evaporation of four chloride brines produced crude salts containing predominantly sylvite, halite, and carnallite. Six sulfate-chloride brines produced crude salts containing primarily schoenite, kainite, leonite, sylvite, carnallite, and halite. Potash grades ranged from 7.2 to 22.2 pct K20, and recoveries from 84 to 99 pct. Sylvite flotation from chloride evaporites, with amine collector, recovered 90 to 97 pct of the potash in a concentrate containing 54.3 to 60.3 pct K20. Fatty acid flotation of the high-sulfate evaporite recovered 78 pct of the sulfate minerals in a 27.8-pct-K20 concentrate. Flotation of the chloride minerals with amine collector recovered 80 pct of the potash in a 59.7-pct-K20 concentrate. Solar evaporation of 10,000 gal of brine recovered 99 pct of the potash in a crude evaporite containing 24.5 pct schoenite and 20 pct sylvite. Continuous flotation in a 100-lb/h process research unit recovered over 95 pct of the potash in schoenite and sylvite concentrates containing 28.0 and 62.3 pct K20, respectively. An economic evaluation suggested a rate of return of 3 pct for a new facility and 9 pct if. the process is adapted to fit an existing plant.

Jan 1, 1984

By Chas. F. Jackson

The work of the mining division is divided between seven sections, each in charge of a supervising engineer, as follows: 1. Metal-mining methods section, the supervising engineer of which is also supervising engineer of the Southwest Experiment Station at Tucson, Ariz. 2. Metal-mining research section. 3. Nonmetal minim section. 4. Coal-mining section. 5. Mine-ventilation section. 6. Mineral-industries survey section. 7. Electrical section. The names of the sections indicate broadly the fields covered by each, and in the following pages the objectives and type of work of each section will be summarized briefly and the active problems listed. The work done during the calendar year 1936 will also be summarized.

Jan 1, 1937

By Lotfollah Nahai

India is one of the fortunate countries that has substantial reserves of many raw materials for producing steel; however, for historical and economic reasons these resources have not been aggressively developed until recently. Production of steel on an industrial scale started in 1912, but annual output was below 1 million tons3 in 1938 and about 1,500,000 tons in 1951. Expansion of the steel industry became one of the objectives of India's economic planning after independence in 1947. The Planning Com¬mission's 1951 report emphasized the importance of steel production, but financial obstacles, emphasis on river valley projects, and priority for increased food production in the First 5-Year Plan (1951-56) did not permit large-scale expansion of steel capacity. The 1956 planned target for crude steel, only 1,650,000 tons, was actually exceeded by production of 1,737,900 tons. In the Second 5-Year Plan (1956-61), however, construction of steel plants received a high priority. Currently three new steel plants, each with an annual capacity of approximately 1 million tons of steel, are nearing completion in Rourkela, Dorgapur, and Bhilai. Simultaneously, the two privately owned steel plants and the small State-owned plant in Mysore have been enlarged and modernized. As a result, India's crude steel capacity will be about 6 million tons in 1961, almost evenly divided between Government-owned and privately owned plants. Actual production in 1960 totaled 3,254,000 tons compared with 2,434,000 tons in 1959. Assuming that the population will be 430 million and that capacity production will be achieved, the 1961 per capita steel output will be only 31 pounds compared with 200 pounds for Japan in 1959. Some Indian experts feel that development of steel-consuming industries merits greater emphasis in the Third 5-Year Plan (1961-66) than expanding existing steel-producing facilities. Nonetheless, the Third 5-Year Plan calls for a 10 million ton annual capacity by 1966 to be achieved by expanding the Government-owned plants in Bhilai, Durgapur, and Mysore, and by establishing a new integrated Government plant in Bokaro, in the State of Bihar.

Jan 1, 1961

By Robert C. Gabler

Evaluation of incinerated sewage sludge as a secondary resource for aluminum, phosphorus, and minor constituents such as copper and zinc was initiated as part of the Bureau of Mines secondary resource program. The elemental composition of sludge ash for 14 plants in 11 U.S. cities was determined. Comparing industrialized cities with cities where most of the sewage is domestic, significant differences in heavy metal content were noted. Various parameters were investigated affecting the extraction of metals and phosphorus from a typical industrial city sludge ash and from a Palo Alto, Calif., sludge ash with a high precious metal content. Three extraction-recovery procedures for metals and phosphorus using sulfuric acid leaching, ion exchange, and various precipitation techniques were investigated. The last procedure developed was a combination approach using a three-stage countercurrent sulfuric acid leach that recovered most of the economic values from the sludge ash and also removed the leachable fraction of elements of environmental concern.

Jan 1, 1979

By C. W. Sill

[In the original Norris and Fay method for determining selenium, selenious acid is reduced by an excess of standard thicsulfate in accordance with the following reaction: H2Se03 + 4Na2S203 + 4HC1 = Na2SeS406 + Na2S406 + 4NaC1 + X20. (1) The excess thiosutfate is then back-titrated with standard iodine solution. The disadvantages of ouch a method are obvious. On an unknown sample, the quantity of thiosutfate required would be difficult to determine; a definite excess is required, but large back titrations would be undesirable. Inasmuch as thiosulfate is decomposed by acid, considerable error may be introduced in this method, the amount depending on the acidity, temperature, concentration of excess thiosulfate, duration of contact between thiosulfate and acid, and other factors, In a critical study of the Norris and Fay method, Coleman and McCrosky3/ show that the method is accurate to less than .1 part per thousand if the excess of this sulfate Is not greater than 5 ml. of 0.1 N solution (in 1.0 ml. of 0.x4 N sulfuric acid) whether the titration is made at 0° or 20°C. A greater excess produced unsatisfactory values at either temperature. Coleman and McCrosky regulated the excess thiosulfate by adding 5-ml. portions of thiosulfate solution followed by the addition of 1 to 3 drops of 2.5 percent potassium iodide in the presence of starch. If a starch-iodine blue color formed locally around the drops of potassium Iodide, the reduction of selenious acid was not complete. On stirring the solution, the local blue color fades and another 5-ml. portion of thiosulfate is added. When addition of potassium iodide fails to produce a local blue color, reduction of selenious acid is complete, and the excess thiosulfate is then back-titrated with standard Iodine solution. The number of equivalents involved in the reduction of selenious acid by either thiosulfate or iodide is the same, and therefore no correction need be made for the potassium iodide. This procedure is much better than the original Norris-Fay titration, but acidity and time would stilt be rather critical factors subject to variation with individual technique. Also, the method still requires the lose of two standard solutions, a rather undesirable factor from the standpoint of routine application.]

Jan 1, 1954

By R. W. Stahl

"This study by the Federal Bureau of Mines was confined to pillaring with continuous mining machines and to mines where total extraction is practiced. Many different conditions and practices in as many coalbeds as possible in Pennsylvania were observed.Pillar extraction or pillaring can be the most productive part of coal mining if done properly; but it also can be the most dangerous if done improperly.Because of the need for more careful planning before and caution during pillaring, many mining companies resort to the undesirable practice of stumping or hogging of pillars with subsequent unnecessary waste of valuable natural resources. Pillaring can be done at reasonable cost and safely, as proven at many mines where complete extraction is practiced and enviable cost and accident records are maintained.Although continuous mining machines are bulky and sometimes difficult to maneuver, they have been used with great success in pillaring. Occasionally, however, a machine is caught, or men are injured by a fall during pillar recovery. This Bureau survey was conducted to ascertain how safe and successful pillaring (especially the removal of final stumps in lifts or the final stump of a pillar), is accomplished in some mines, while others have considerable difficulty under similar conditions.The Bureau hopes the information to be presented in this publication will prove beneficial to those who wish to recover more pillar coal and to improve their accident record during such procedures."

Dec 1, 1959

By Charles Will Wright

This paper is one of a series dealing with mining problems and summarizing the data contained in the Information Circulars on individual mines that have been prepared by the managers or superintendents and published by the Bureau of Mines. The purpose of this paper is to present the problems encountered in the development of an efficient mine organization and to show the means used by certain mining companies in promoting efficiency. There is also a discussion of the advantages and disadvantages of the various systems of paying and handling labor and a description of their application at the individual mines.

Jan 1, 1932

By Pedro Lilienfeld

This Final Report describes a program whose objective was to design, develop, fabricate, and test an airborne mass monitor for unattended and recording measurements of the concentration of dust in mining environments. Sensing collection are performed by beta-radiation attenuation and inertial implementation respectively. The instrument is portable, battery or line operated provides a digital printout of the mass concentration during each selection sampling period, as well as the accumulated mass of dust, and the elapsed sampling time.

Jan 1, 1974

By Vernon O. Markworth

This report contains the results of tests performed on three large diesel engines to determine their ability to meet selected criteria of the Mining Enforcement and Safety Administration Regulations for equipment used in gassy, non-coal mines. Study efforts were first directed toward determining the types of equipment expected to be used in underground oil shale mines. Three typical engines in the 800-1200 horsepower range were then selected for testing. Intake flame arresters, exhaust scrubbers, and water jacketed exhaust system were designed and built for each engine. During testing, each engine was evaluated for its gaseous emissions output, adequacy of the exhaust gas cooling system, ability to withstand internal explosions, and adequacy of the flame arresters. Surface temperatures of the engine and exhaust cooling system were determined under full load operation.

Jan 1, 1978

By Alan A. Campoli

The U.S. Bureau of Mines conducted research to characterize longwall gob loading under bump-prone geologic conditions. Bureau-designed stress meters were installed in the floor rock beneath two longwall panels and coal pillars in the gate road between them. Gob and gate road pillar stress was monitored continuously by a state-of-the-art data acquisition system. The timing of the final destruction of the abutment pillar's load-bearing core was optimal, since the pillar is located between two gob areas and no longer of significant importance for ground control. Maximum stress was observed immediately in front of the longwall face, and this pressure quickly dropped as the face moved past the instruments. The center of the longwall panels regained significant overburden load, while the instruments located less than 100 ft from the edge of the panel showed little or no increase in pressure due to gob reloading.

Jan 1, 2010

By F. E. Diebold

The wastewater-treatment system of the Anaconda Mining Co., at its Butte, MT., operation has been physically and chemically characterize modeled on a computer and investigated with respect to alternate systems for economic heavy metal recovery. The system involves lime addition to a mixture of acid underground copper sulfide mine water, acid effluent water from the iron induced precipitation of copper from acid leach solution and basic suspensions of solid effluent from a concentrator plant. Experimental chemical analysis and predictive computer calculations shows that the monosulfllte and disulfllte complexes of transition metals (Iron II being dominant) and alkaline earths are 40% of the total dissolved metal load of both acid streams. The suspended solids (30% by weight) in the basic concentrator slurries are dominated by quartz and pyrite and also contain kaolinite muscovite, biotite and undissolved lime. The mixture of these three streams result's in major reductions in concentrations of Al, Cu, Fe, Mg, Mn, Sir and Zn, and a pH >7 with calcium, sodium, potassium, and sulfate being the major dissolved ions. The treatment system has been simulated in the laboratory and accurately modeled on a computer. The computer program, an altered REDEQL-EPAK, is capable of accurately predicting the amount of lime required to reach a desired effluent water. Preliminary research has indicated the usefulness of electroprecipitation as a means of recovering the valuable metal load and providing an EPA acceptable effluent.

Jan 1, 1982