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By Heine Kenworthy

"INTRODUCTION In 1930 the Shenandoah-Dives Mining Co. near Silverton, Colo., put into operation a newly erected, 300-ton selective flotation plant to mill complex ores from its nearby mine. The operation was a steady producer and was enlarged to treat 600 to 800 tons a day. In 1942 the company opened and started milling an area in the mine containing semioxidized ore. The valuable mineral content of this ore was considerably higher than in, the straight sulfide ore previously handled alone. The mixture of clean sulfide and semi-oxidized ore was difficult to treat; consequently, tailing losses, especially with respect to lead, were high. A few years later, in order to study the possibilities of obtaining higher recoveries by a modification of the mill flow sheet, a 1,200-pound sample of mill, feed, taken over a period of several days by the company, was submitted to the Mississippi Valley Experiment Sta¬tion for testing-. Although this sample proved to contain more than twice as much lead as the average yearly mill feed, the same problem of recovering the oxidized values was present.A résumé of the ore-dressing treatment used in the Shenandoah-Dives mill follows. After crushing, the ore passes through a ball mill, the minus 5-mesh discharge of which is distributed to three tables. A finished lead concentrate is made on the tables, and the table tailing goes to the classifier which is in closed circuit with the ball mill. The classifier overflow is treated -by flotation to obtain a bulk sulfide concentrate at a relatively coarse size. The bulk concentrate is thickened and reground to about 95 percent minus 325-mesh before flotation treatment to separate a lead-copper and a zinc concentrate. A typical monthly average showed that the table concentrate contained about 45 percent lead, 1 percent copper, 4 percent zinc, 12 ounces of gold, and 40 ounces of silver; that the lead flotation concentrate contained '35 percent load, 6 percent copper, 7 percent zinc, 3.5 ounces of gold, and 50 ounces of silver; and that the zinc flotation concentrate contained 2 percent lead, 0.5 percent copper, 60 percent zinc, 0.15 ounces of gold, and 4 ounces of silver. Recoveries in salable products were roughly b5 percent of the lead, 70 percent of the copper, 45 percent of the zinc, 85 percent of the gold, and b5 percent of the silver."

May 1, 1948

By V. B. Dale

San Manuel has been a modern prodigy from its inception to its present status as a block-caving operation producing 33,000 tons per day. The deposit was discovered, prospected, and developed with modern techniques, and nearly all planning was done from results of an extensive drilling program through an average overburden of 670 feet. The Federal Government had a prominent part in the discovery and primary development of San Manuel. The first 17 holes were drilled by the Bureau of Mines, and discovery of the large, low-grade, disseminated copper deposit is credited to the Bureau. A loan fund of 94 million was granted through the Reconstruction Finance Corporation to the San Manuel Copper Corp. for development of the deposit and erection of concentrating and smelting facilities. Then, while the mine was still being developed, the Defense Materials Procurement Agency contracted to buy a large amount of copper at a pegged price.

Jan 1, 1962

By Worthen Bradley

This paper describing the metallurgical practice and costs at the reduction plant of the. Sulphur Bank Syndicate, Clearlake, Calif., is one of a series of papers on the treatment of ores being prepared by the Bureau f Mines. The reduction plant and mine of the Sulphur Bank Syndicate are on the eastern shore of Clear Lake, in Lake County, Calif., 4 miles from the town of Clearlake and 125 miles north of San Francisco.

Jan 1, 1931

By M. A. Elliott, H. H. Schrenk, L. B. Berger, John C. Holtz

"INTRODUCTION Among the hazards that may attend the use of Diesel engines in mines, tunnels, or other underground operations the presence of harmful or objectionable constituents in the exhaust gas must receive due consideration to prevent the formation of unsafe or unhealthful working environments in these places. Previous reports of this series have presented discussions of the composition of exhaust gas from engines in proper mechanical condition, 6/ the effect of adding some of the exhaust gas to the intake air of the engine, 7/ the effect of operation in atmospheres containing natural gas, 8/ and the effect on exhaust-gas composition of conditions that influence the characteristics of fuel injection in Diesel engines. In all these studies the properties of the fuels used were in general conformity with specifications usually recommended by the manufacturers of Diesel engines. In evaluating the physiological significance of the various components of the exhaust in these experiments, the toxic or objectionable gases determined were carbon monoxide, carbon dioxide, oxides of nitrogen, and aldehydes. Because of the low sulfur content of' these fuels, compounds such as sulfur dioxide and sulfur trioxide were not determined, although in discussion of the test results attention was directed to the fact that if fuels of higher sulfur content were used, the concentration of such compounds in the exhaust would become a significant factor in establishing the quantity of ventilating air required to furnish satisfactory dilut1on of the exhaust gas in underground working places."

Jun 1, 1943

By Tobias W. Goodman, Joseph Cervik

This Bureau of Mines report investigates the horizontal trajectory of boreholes drilled in coalbeds using the rotary drilling technique. Test holes drilled in coalbeds showed that the path of a borehole in the horizontal plane depends on drilling assembly configuration, drill bit rotation, and coalbed geologic features. An assembly that contained an 18-ft (5.53) long drill collar and two centralizers had the best horizontal stability evidenced by trajectories that deviated less than 16 ft (4.9 m) from a target at 1,000 ft (305 m). Removal of one of the centralizers resulted in a loss of control of hole trajectory in the horizontal plane. Generally, holes tended to turn to the right, presumably because of right-hand rotation of the bit. Deviations from the original bearing line were as much as 200 ft (61 m) or more at a depth of 1,000 ft (305 m).

Jan 1, 1988

Apply state-of-the-art monitoring and computer systems technology to remotely monitor geostructural data and evaluate ground conditions in near real-time. Background Recently, the coal mining industry has progressed dramatically from a labor-intensive industry to highly mechanized and automated systems achieving significantly higher production rates. In underground longwall coal mines, production and face advance rates have increased by almost tenfold in the last 15 to 20 years. With increasingly high advance rates, geologic anomalies which affect rock mass quality are encountered more frequently, far exceeding the current rate at which ground control information can be processed and analyzed. As a result, mine operators find themselves with insufficient time or resources to cope with the rapidly changing ground conditions. To keep up with the technological advancement in mining and the associated ground control problems, the Bureau of Mines is conducting a multi-phase research pro¬gram to implement a computer-assisted Ground Control Management System (GCMS). Research is ongoing at present, but when completed the system will be designed to 1) monitor and evaluate data on rock properties, geologic conditions, and rock mechanics data from underground sensors in near real-time; 2) interpret the analyses to evaluate the interaction between various critical ground control parameters; 3) assess the structural integrity of the mine; and 4) determine failure modes and provide recommendations for control measures, design modifica¬tions, and alternative support procedures. The system will be expanded into its full capability during various phases of this research program.

Jan 1, 1991

By N. S. Dalal, Xianglin Shi

"The mechanism of vanadium(V) V ) toxicity is still not fully understood in spite of extensive current effort (1-3). The presence of a vanadium(V) V ) -dependent NAD ( P )H oxidase in cell membranes suggests that at least one of the pathways involves oxidation of NAD(P)H (1-3). Considerable effort has therefore been devoted to finding the mechanism of NAD ( P ) H-oxidation by va¬nadium( V ) (1-19). Recently Liochev and Fridovich (4, 16) provided a critical review of vanadium( V) -stimulated NAD (P )H oxidation by plasma membranes. They out¬lined a mechanism in which vanadium(V) V )-stimulated oxidation of NAD ( P )H by biomembranes involves an O2 - initiated free radical chain reaction (4 ). While the above may be the major pathway for the vanadium-me¬diated NAD (P )H oxidation in membrane-related sys¬tems, some recent results suggest that in the presence of NADPH the flavoenzyme glutathione reductase can function as a vanadium(V) V ) reductase (18). Because of the significance of this result in relationship to the mech¬anism of vanadium( V) metabolism and the novelty of the metal-reductase behavior of a flavoenzyme, we have car¬ried out additional studies on one-electron reduction of vanadium( V) by two other, related flavoenzymes: lipoyl dehydrogenase and ferredoxin-NADPH oxidoreductase. These two enzymes were selected because they are known to catalyze a one-electron reduction of Cr ( VI ) (19-21 ), which is isoelectronic with vanadium( V ).The present study also reports on the generation of hydroxyl ( • OH) radicals in the vanadium( V) -flavoen-zyme redox system without exogenous H2O2. The • OH study was undertaken because • OH radicals are known to be generated in reactions of vanadium( IV) with H2O2 (17,18,22-27). For example, Piette and co-workers (17, 22) have studied effects of vanadium(IV) IV ) on lipid per-oxidation and NADPH oxidation and suggested that va-nadium( IV) -induced • OH radical formation may play an important role in vanadium( V) toxicity. Carmichael (25, 26) investigated the reaction between a RNA /VO 2' complex and H2O2 with a view to probe the possible re-lationship between vanadium( IV) -mediated • OH radical generation and DNA damage. He has suggested that in this reaction the • OH radical adds to the C (5) carbon of uracil, causing nucleotide damage, similar to what occurs in the nucleotide /Fe2+ / H2O2 reaction (28) and in y-irradiated aqueous solutions of nucleic acids (29 ). To our knowledge, however, there is as yet no report on ·OH radical generation in any reaction involving the reduction of vanadium ( V) by a well-characterized enzyme, without exogenous H20 2 • The present study provides evidence that ·OH radicals can form in a flavoenzyme-mediated reduction of vanadium( V) to vanadium( IV) and that this process involves also the reduction of molecular oxygen ( 0 2 ) to H20 2 • The H20 2 thus generated reacts with vanadium( IV) to produce ·OH radical, in analogy with the Fenton reaction ( Fe2 + + H20 2 - Fe3 + + OH- + ·OH)."

Mar 1, 1992

By Andrew M. Leszcykowski

A 1981 U.S. Bureau of Mines investigation indicates the Panamint Dunes Wilderness Study Area (WSA) has one active (intermittent) mine,--borrow pit MS 242 owned by the California Department of Transportation (Cal Trans). This mine produces cinders for road base and traction grit. It contains about 900,000 tons of inferred reserves. Examination and sample analyses indicate the Panamint Dunes deposit, covering about 480 acres of the WSA, may have silica resources and the Green Quartz Claim may have copper resources. Carbonate rocks occur in the WSA, but stone resources have not been identified. Adjacent to the WSA, the Big Four Mine contains 35,000 tons of inferred subeconomic zinc-lead-silver resources, and may have additional resources. Sample analyses indicate the Apple 1 Claim, also adjacent to the WSA, may have silver-lead-zinc resources.

Jan 1, 1985

By W. H. Coghill, F. D. DeVaney

"Introduction Numerous investigators have studied grinding. Each has contributed his bit to a literature that is difficult to correlate. Too many of the results have been transformed into curves with no many ""inflection points"" and ""counterflexures"" that they obscure the issue.Some of the investigators have neglected the very essence of the problem, namely, the power and the amount of material to which a known amount of work was applied. The purpose of this paper is to show the ease with which results can be interpreted when these quantities are duly recognized. Some grinding tests will be given for illustration.Grinding studies are of two kinds: (1) Study of the character of the ore and (2) study of the performance of the machines. Several ores may be crushed by a given machine, or several machines may be used on a given ore. The illustrations given in this report cover both objectives.Grindability Characteristics When the ores are being studied the information sought is grindability characteristics (grain-size distribution) and the grindability (work required to produce new surface) of a group of ores.When the study is of the machines, several machines are used for a given ore or given types of ores, and the grinding performances of the machines are compared by a grain-size study.Table 1 gives the grindability characteristics and grindability of six substances, one of which is coal. The substances are arranged from left to right in progressing order of tons per horsepower-hour. Curves and graphs are not needed for elucidation. The secret of the ease of interpretation is the order mentioned and the similarity of the sizing analyses. Power records must be complete in grinding studies.The grinding device was a ball, plunger, and mortar called the drop weight.' It may be used to advantage when the amount of material to be tested is too small for the orthodox machines.The upper part of table 1 shows the grindability characteristics by the cumulative-sizing analyses. Note how closely the percentage weights agree for a given sieve size. The lower part shows the grindability in terms defined elsewhere. The present paper should be read in conjunction with that paper."

Jun 1, 1934

By Richard A. Busch

Inadequate engineering design criteria for coal refuse embankments has allowed hazardous impoundment structures in coal mining areas to be created. A necessary first step to develop adequate design criteria is the determina¬tion of basic, respresentative physical property data on the materials that constitute typical refuse embankments. An extensive field and laboratory program was undertaken by the Federal Bureau of Mines. Much physical property data was generated. Additonal petrographic analysis and large scale triaxial compression testing was performed by others. The data presented here should aid in establishing design parameters for coal refuse embankments

Jan 1, 1974

By Heine Kenworthy

In 1930 the Shenandoah-Dives Mining Co. near Silverton, Colo., put into operation a newly erected, 300-ton selective flotation plant to mill complex ores from its nearby mine. The operation was a steady producer and was enlarged to treat 600 to 800 tons a day. In 1942 the company opened and started milling an area in the mine containing semioxidized ore. The valuable mineral. Content of this ore was considerably higher than in the straight sulfide ore previously handled alone. The mixture of clean sulfide and semi-oxidized ore was difficult to treat; consequently tailing losses, especially with respect to lead, were high. A. few years later, in order to study the possibilities, of obtaining higher recoveries by a modification of the mill flow sheet, a 1,200-pound sample of mill feed, taken over a period of several days by the company, was submitted to the Mississippi Valley Experiment Station for testing. Although this sample proved to contain more than twice as much lead as the average yearly mill feed, the same problem of recovering the oxidized values were present.

Jan 1, 1948

By Launa G. Mallett, Dana Reinke, Charles Vaught, Michael J. Brnich

As mines become safer and major disasters fewer, the number of experienced emergency responders is decreasing. This decrease will create a gap in response expertise which could have serious ramifications during future mine disasters. While working toward safety goals which may make emergency response obsolete, it would be reckless not to acknowledge that the potential for disaster still exists and that the protection of miners in such circumstances must remain a priority. The Mine Emergency Response Interactive Training Simulation (MERITS) is a computerized mine emergency simulation that meets a variety of needs. It allows personnel in leadership positions to test their knowledge and skill. Groups of individuals composed of representatives from mining companies, labor, and government agencies can practice working together during the simulated mine emergency much in the same way an actual emergency would require. An individual could also run the program to enhance his or her response skills. With this training tool, responders will be able to learn from their mistakes before facing situations with potentially catastrophic consequences. This paper discusses MERITS and its use in providing command center training.

By Barbara J. Halpern

There?s no denying that mining is a male-dominated industry. Yet thanks to technologies developed over the last 20 years, societal changes in sex role stereotyping, individual determi­nation, and the willingness of companies to train women, there are no jobs in mining today where women are not represented. Women are drillers and electricians as well as drivers of heavy equipment and haulpack trucks. They perform jobs ranging from field exploration and metallurgy to clerical and janitorial and warehousing positions, from prospectors and underground blasters to geologists and land reclamation experts, from communicators to legal experts on mining law and more. The Women?s Mining Coalition, founded in 1994 to shepherd responsible legislative mining reform, estimates that 20 percent of the workers in the mining industry are women. Although women are concentrated in clerical and adminis­trative jobs, at least 10 percent are in non-traditional, hardhat jobs, claims the group. There are women in management, but the numbers in senior management remain small, especially in larger companies.

Feb 1, 1998

By John H. Soule

The Royal John mine was examined in November 1942 by a mining engineer of the Bureau of Mines, who proposed development of the Royal John and other properties in the area. Geologists of the U. S. Geological Survey studied the area in 1943 and 1944 and made definite recommendations. Also, in 1943 the Peru Miring Co. mapped the Royal John and did considerable diamond drilling. The Bureau of Mines started the Royal John portion of a project pertaining to the general district in April 1944. This project was completed in Juno 1945. The work, consisting of diamond drilling, was supervised by Robert O. Hill, mining engineer, and the results were published in Report of investigations 3904, Exploration of Grey Eagle, Grandview and Royal John Claims, Grant County, N. WIC. In 1947 and 1948 the Royal John was re-examined by a Bureau engineer, and additional development to increase the reserves of low-grade lead-zinc ore was proposed. This project was started in August 1948 and completed in Juno 1949.

Jan 1, 1950

By Jerome Apt

This manual has been prepared fur the help and guidance of underground coal mine operators. It details both common and unique engineering methods by which the respirable dust, which is generated in coal mines, can be controlled. This document was compiled by Apt, Bramer, Conrad and Associates, Inc. under contract number H0111464, issued by the U. S. Bureau of Mines and forms Volume II of the final report. This contract was authorized by and executed pursuant to the Federal Coal Mine Health and Safety. Act of 1969 (P. I. 91-173; 83 Stat. 742).

Jan 1, 1972

By R. L. Schmidt

Research conducted over the past 20 years in France, Great Britain, and the United States on the use of the large-hole burn cut has established cer¬tain advantages for this system. Advantages include longer pull and more complete fragmentation from blast rounds. However, research is needed to establish a set of parameters for optimum performance. As part of the Bureau of Mines Advancing Mining Technology for Marginal Resources program, the Twin Cities Mining Research Center, Twin Cities, Minn., acquired a horizontal rotary drill capable of boring holes up to 24 in. in diameter. This was used for a series of underground experiments at White Pine mine, White Pine, Mich., during 1973. Exceptional results were obtained with a 12-1/4-in void hole that yielded up to 18 ft of pull in a 10- by 20-ft drift, Fragmentation was excellent, and the compactness of the muck pile facilitated loading.

Jan 1, 1975

By C. A. Komar

Renewed interest in the underground gasification of coal evolves from comprehensive studies of earth fracture systems that indicate that the movement of fluids can be controlled in the coalbed. In particular, directional property studies of natural microfissure occurrence, permeability, ultrasonic velocity, tensile strength, and orientation of intervals of inherent rock weakness, together with geologic structure setting and fracture trace analysis, can predict the gaseous flow paths in the coalbed. Having this information, the dominant direction in which gases generated and/or liberated by heat would move can be determined so that appropriate well patterns can be developed. Together with advances made in drilling technology that permit long horizontal holes to be drilled through the coal seams, tests can be conducted to determine whether directional control will permit devolatilization of the coalbed and gasification of the remaining hot coke in a systematic manner to produce a low-Btu gas suited for the generation of electricity.

Jan 1, 1973

By R. M. Santmyers

Except for optical purposes and a few other special uses quartz and quartzite are to a considerable degree interchangeable. This also may be said with respect to pulverized quartz and ground silica sand, which are discussed in a separate paper of this series. All these materials, except perhaps quartz crystals of optical grade, are abundantly available in many parts of the United States. In the form of ordinary crushed stone much of it is sold at $1 a ton or less, and ordinarily

Aug 1, 1931

By P. A. Bloom

Bureau of Mines research was conducted to develop effective separation methods that might be used in exploiting substantial tonnages of complex barite-fluorspar ores in Arizona. The exploitable reserves now may be increased as recent batch and continuous flotation tests demonstrated that a complex barite?-fluorspar ore from the Red Chief deposit, Yuma County, Ariz., could be selectively treated to concurrently produce (1) fluorspar and (2) a barite byproduct of marketable grade. The sample contained 24.8 percent CaF2 and 24.3 percent BaS04. Processing comprised production of a fluorspar product containing 97 percent CaF2 with an 82 percent recovery, using a sodium fluoride-lignin sulfonate-fatty acid reagent combination. Concurrent retreatment of the fluorspar tailing, using sodium cetyl sulfate as a collector, yielded a barite product of 94 percent BaS04 grade with a 71-percent recovery. The products met specifications for acid-grade fluorspar and drilling mud-type barite.

Jan 1, 1963

By William A. Beck

"In 1912 bauxite was discovered in the Andersonville district, which lies in the 28th and 29th land districts of Georgia and comprises parts of Sumter, Macon, and Schley Counties. Mining was begun in May 1914 by the Republic Mining & Manufacturing Co. Considerable ore has been produced in this region since that time by individual interests and by the American Cyanamid & Chemical Corp., which acquired the property formerly owned by the Republic Co.The area was examined in the fall of 1941 by representatives of the Bureau of Mines and the Geological Survey, after which a prospecting program was begun by the Bureau. Drilling was started on December 26, 1941, and continued until November 18, 1943. A total of 1,192 holes was drilled in the district, and 3,679 samples were taken and analyzed.Mineral exploration agreements were signed by 146 property owners covering 42,128 acres. Holes were drilled on 121 of these properties, which have a total area of 38,778 acres.Drilling under this project disclosed several new deposits, of which four have been completely delimited. Previous prospecting in this area by mining companies did not find bauxite, as it lies under heavy overburden. Work by the Bureau indicates 14,412,000 long tons of ore containing 30 percent or more alumina. The total tonnage is divided as follows:Georgia State Highway Routes 26 and 4-9 traverse the district. The Central of Georgia Railroad passes through the center of the entire district (see fig. 1).The project was initiated by J. R. Thoenen, supervising engineer, Non-metals Mining Section, Mining Division, Bureau of Mines. It was under his general supervision until July 1942, after which it was under the general supervision of E. J. Lintner and Rowe McCrae, district engineers for Georgia, South Carolina, and Flordia, respectively.John C. Feeley, Jr., was project engineer from December 1941 to April 1942. Other engineers who assisted in the work on the project are R. E. Babcock, T. M. Romslo, Don M. Coulter, and Walter T. Lewiecki.Acknowledgment is due the metallurgical staffs at College Park, Md., and Tuscaloosa, Ala., for analyses of samples and beneficiation tests.Acknowledgment is also expressed to Alfred D. Zapp, M. W. Harris, Elmer Kneedler,and Parke D. Snavely, of the United States Geological Survey, for their aid, data, and maps.Bauxite was discovered in the Andersonville district in 1912 on lot 187 of the 28th land district, in Sumter County. This lot is situated about 1.5 miles west of the Flint River, on the south slope of the valley of Sweetwater Creek. Mining was started in May 1914 by the Republic Mining & Manufacturing Co. This and adjacent properties were acquired in 1930 by the American Cyanamid & Chemical Corp., which has been operating there since."

Dec 1, 1949