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By Maurice C. Fuerstenau

The kinetics of leaching galena with ferric chloride and ferric nitrate have been examined as a function of ferric concentration, salt concentration, temperature and particle size. Diffusivity of ferric complex ions was also established as a function of ferric chloride concentration and temperature. In the presence of 3 M NaCl, leaching rate is controlled by product layer diffusion when ferric chloride is added as oxidant. With NaCl concentrations less than 3 mole/liter rate decreases with decreased NaCl concentration, and, thus, rate is apparently not controlled by product layer diffusion. It is suggested that rate is controlled by lead chloride solubility at the reaction interface under these conditions. When ferric nitrate is added as oxidant, leaching rate is limited by chemical reaction control. An electrochemical model is presented. Activation energies are 8.1 and 11.3 kcal/mol in the ferric chloride and ferric nitrate systems, respectively.

Jan 1, 1984

By Jonathan E. Ludlow

A field test was conducted to demonstrate and quantify the relationship between deep cutting and the creation of airborne respirable dust for longwall mining With a double-ended ranging drum shearer. The testing program was carried out on the 3 North longwall of North American Coal Company's Quarto No. y mine in Claringten, Ohio. Continuous recordings of the dust levels were made at both the midface and tail ate areas. Data were collected during 27 shifts during which time 81 complete mining, cycles took place. Both drum speed and the number of picks per line were varied systematically during the testing program to alter the depth of cut while the production rate was held constant by maintaining a constant haulage speed. The test results indicated that at the midface position, airborne respirable dust was strongly dependent upon the depth of cut as influenced by both the drum speed and number of picks. Drum speed had a much stronger effect than number of picks over the experimental range, since a halving of drum speed reduced dust levels by approximately 60 percent while removal of every other vane pick resulted in only a 2.1 percent reduction at constant production. At the tailgate position, however, neither effect was strongly apparent. A tendency for the slower drum speeds to he associated with reduced power consumption and higher haulage speeds (and therefore production rates) was also noted. It is recommended that longwall operators oper¬ate at the lowest available drum speed wherever possible.

Jan 1, 1981

On April 1, 1982, the Bureau of Mines and the Department of Energy entered into an Interagency Agreement to develop an enhanced computer cost model for uranium in situ leach mining. The original computer cost model contained data base information related to two regions; the Wyoming basin region and the South Texas trend area. The enhanced cost model contains additional information on San Juan Basin type deposits. This addition is significant because it expands the model's capabilites to include one of the largest uranium producing areas in the United States and developes costs related to uranium production from in situ leach mining. The data base was expanded and modified to include changes necessary for San Juan basin type deposits. These changes included, but were not limited to, state and local taxes, royalty payments, depth of deposits, drilling costs, and electrical costs. Also site visits were taken to verify many of the base case parameters. Consequently, the data base has been incorporated into the computer program and existing software was modified to provide for the additional data. Information was obtained on drilling coats and therefore the current program more accurately reflects these costs to depths of 2500 feet. This depth parameter has been expanded to include Wyoming Basin and South Texas scenarios also. Verbal communications were held with one operator in the Crownpoint, New Mexico area as well as the state regulatory agencies to help validate the expanded model. As a result of these changes, several tables have been included, summarizing changes in the new default parameters and the overall range of input parameters.

Jan 1, 1982

By Terry R. Neumann

During 1983, U.S. Bureau of Mines personnel examined mines, prospects, and mineralized zones to evaluate the mineral resources and potential of the Funeral Mountains Wilderness Study Area (WSA), Inyo County, California. Eleven mineral properties and two mineralized zones were examined during this study. Of these, six are within the study area and seven adjacent. There are no active mines, in the WSA, nor is there evidence of past production from any claim within the study area. The WSA contains no identified mineral resources. However, occurrences of bentonite, zeolites, and strontium were found in the area. There is little likelihood for resource development of any occurrence in the WSA. The area, in the Basin and Range Physiographic Province, is dominated by a Paleozoic marine sequence. Segments of Tertiary continental fluviolacustrine sediments, including volcaniclastic rocks, abut and overlie the Paleozoic rocks in fault controlled basin areas. Significant concentrations of bentonitic clay and zeolites occur as alteration products in Tertiary tuffaceous sedimentary rocks. However, they are generally low-grade, thin, and discontinuous, precluding commercial development. Limestone, quartzite, and sand and gravel in the area are suitable for many types of construction uses, but similar deposits outside the WSA are closer to markets. No energy resources have been identified in the WSA.

Jan 1, 1984

By H. E. Thomas

[The Bureau of Mines has conducted a field hydraulic fracturing experiment to determine the preferential orientation of induced fractures in oil shale at a depth of about 400 feet in the Green River Basin of Wyoming. The hydraulic fracturing treatment was performed by injecting extremely viscous water-base gel and 8- to 12-mesh sand into the oil shale through straddle packers set in an impermeable section of smooth-walled, 6-1/4-inch-diameter open hole. An impression packer proved that a horizontal fracture, which has an average width of about 1/2 inch at the borehole, was induced. A corehole drilled 100 feet from the fractured well intersected the fracture and confirmed its horizontal orientation. Because a horizontal fracture was successfully initi¬ated, it is inferred that the creation of multiple, closely spaced horizontal fractures may be feasible in Green River Basin oil shale.]

Jan 1, 1972

By John Rusnak

The Coal Mine Roof Rating (CMRR) is a practical rock mass classification system for use in design of mine openings. Data can be obtained for this purpose from exploration drill cores if simple geotechnical logging and rock mechanics testing is conducted. The CMRR is an excellent method to quantify rock characteristics for engineering purposes. It bridges the gap between geologic description and engineering design. The CMRR was utilized in the design of a 10,000 fl. long coal belt conveyor tunnel connecting an Eastern Associated Coal Corp. mine and preparation plant in Boone County, West Virginia. Data gathering and analysis techniques are discussed involving the calculation of the CMRR and its application in the design of the tunnel, which was driven through a thin coal bed zone. The preliminary findings have correlated well with actual roof and mining conditions encountered during driving the tunnel and it is concluded the CMRR is an effective method to utilize geologic data from exploration core holes for engineering analysis and design.

Jan 1, 1998

By R. H. Hiltz

One of the major hazards in underground coal mining is fire. The inherent hazard of fire is exaggerated by the nature of coal mining restricted areas, the highly combustible nature of coal itself, and a potential for explosive concentrations or dust and gas in the air it becomes imperative therefore to make every effort to eliminate the causes of fires, while providing the most effective means possible to control and extinguish those fires which may occur it has been demonstrated by prior work that the problem of control increases in proportion to the time necessary to institute control procedures. There are several areas of underground coal mining with obvious fire potential. Some of these, like belt heads, have reliantly undergone improvements in standby fire control devices Others, although having fire suppression systems available to them, have not received as complete a systematic study of their problems. Face machinery, particularly those without a water supply, falls in this latter category.

Jan 1, 1973

By Francis X. Cannaday

Equipment and techniques were developed with Bureau of Mines facilities for measurement in the laboratory of sonic shear wave velocity in variously shaped rock specimens in a wide range of sizes. A variety of rock types was tested. The shear wave front is produced by electronically excited, piezo-electric ceramic) disk-shaped transducers. Transmitter and receiver are interchangeable. Special equipment components were Bureau produced; other components were commercially available. The equipment permits quick measurement of shear wave velocity on variously shaped specimens with a minimum of specimen preparation. The technique, under favorable conditions, allows for determination of the moment of arrival of the shear wave when it is superimposed on a weak longitudinal wave.

Jan 1, 1968

By Swades Kumar Chaulya, Vikash Kumar, Sushma Kumari, Naresh Kumar, Girendra Mohan Prasad, Monika Choudhary

Opencast mines are vulnerable to inclement weather conditions as it disrupts the day-to-day activities at these mines. To address the problem, a perceptive driving assistant system (PDAS) has been developed to increase the visibility of real-time video of the road in front of the vehicle for operators of heavy earth-moving machinery (HEMM) at opencast mines in harsh weather conditions.

Apr 1, 2023

By F. S. Kendorski

This report presents the results of a search for viable-self-drilling roof bolt concepts, detailed development, design, and manufacture of such bolts that drill their own holes, and testing in the laboratory and in the field in two different coal mines of three self-drilling roof bolts. Three new types of bolts were designed and tested, which drill their own holes and then anchor in continuous operation. These were a spring-actuated mechanical expansion shell, a slot and wedge, and a self-contained resin anchor bolt. Such bolts when fully developed for mine use would allow safer and remote installation of ground support and increase productivity. Recommendations are given for further work to improve drilling and anchorage performance.

Jan 1, 1979

By J. A. Finch, A. R. Laplante, R. Espinosa-Gomez

"The Niobec concentrator rejects up to /5% of the Nb as slimes (-10u.m). The recovery of Nb from these slimes by column flotation is being studied. An essential condition for selective flotation is slimes dispersion. A particle size analyzer, the Sedigraph 5000D, was used to monitor dispersion in plant waters with combinations of organic and inorganic dispersants and flotation reagents. Flotation reagents were particularly detrimental to dispersion with sodium silicate. The best dispersion conditions were selected for column flotation tests. These tests revealed that reagent combination had a pronounced effect on froth stability. Careful frother selection achieved good froth stability under conditions of good dispersion. Plant water increased the required dispersant concentration causing mineral depression.IntroductionSlimes (-10 u.m) rejected at Niobec contain up to 15070 of the over-all Nb content . Recovery of Nb from these slimes would significantly increase over-all recovery. A suggested recovery route involves two phases: (1) carbonate flotation (to remove most of the carbonates) depressing silicates and pyrochlore (as currently done at Niobec); and (2) selective (direct) pyrochlore flotation from the silicates. Phase 2 has been addressed and several routes to achieve selective flotation are available. Phase I was attempted with the selective reagent scheme used at Niobec but a considerable amount of pyrochlore floated with the carbonates due to poor slimes dispersion."

Jan 1, 1987

By Jorge Rodríguez Velarde

Dado que la extracción de metales exige revisar la tecnología existente para así proveer de los metales necesarios que se requieren para suplir esas exigencias. En ese sentido, el presente texto describe la lixiviación bacteriana como la tecnología de vanguardia para recuperar elemetos metálicos a partir de materiales mineros marginales. Los sulfuros metálicos tienen propiedades electroquímicas que pueden transferir electrones, generando reacciones tipo redox. Por ello, los thiobacillus thiooxidans y los thiobacillus ferrooxidans para su metabolismo, requieren ganar energía de aquellos electrones ubicados en orbitales de un alto nivel energético. De esta manera, una bacteria puede catalizar un proceso redox con un sulfuro metálico. La pérdida de electrones en un sulfuro significa enlaces rotos y esto origina la disolución del sulfuro metálico. Así, se postulan dos mecanismos por el cual se produce la disolución del sulfuro.

Mar 1, 1983

By M Thierry Bernart

The software QUALITIR is a software developed by CNSIDCI, framework on five research and experimentation years. This conceived tool by specialists for professionals is a decision aided design tool concerning mining. It makes party the rare software regrouping the different themes approached by the profession namely, the general idea of blast design, blasting sequences, the fragmentation as well as the study of vibrations. Henceforth it is by the intermediary of such tools that performances in term of profitability, security or impact on the environment will be able to be realized.

Jan 1, 1997

With the advent of the environmental "green" movement of the 1960s, eventually leading to Earth Day 1970, Congress responded by passage of the National Environmental Policy Act (NEPA), 1970. NEPA gave impetus to a flood of federal acts and laws in the subsequent three decades. Many of those protecting man's environment, health, and well-being also affect mining. For purposes of this chapter, a current mineral law summarization lends itself to a division into two parts: viz., Part I, General Mining Law, and Part II, Enviromining Law. The word enviromining has been coined by the author and is defined and used herein as those federal and state statutes and regulations that were created to provide protection and preservation of man's environment, health, safety, and welfare, and they have particular application to and affect on mining activities. They are listed and treated under Enviromining Laws in Part II. Mining, as a basic industry to provide the essential minerals for mankind's necessities and well-being, truly reflects the mining industry's slogan, "If it can't be grown, it must be mined." Without the basic minerals and rocks won from the earth by mining and mineral processing for their valuable physical properties or chemical constituents, man would soon be forced to revert to the cave-dwelling age. Unfortunately, for man to survive in the "manner of life to which he has become accustomed," he is caught between the demands of cleaning up his deteriorating environment and a continued supply of his basic requirements and amenities for daily living supplied by mining of the earth's minerals. He must have "clean living" at the same time with "good living;" neither is expendable. A very high pricetag accompanies this essential and critical choice which must be paid by society. The United States is internationally recognized as the world leader in environmental matters. Many countries are following suit, principally the other Anglo nations. Because US law is founded and based on English law, on occasion, Anglo-American law is referred to and cited as authority in litigation anywhere in the Anglo-American world of jurisprudence. For this reason, and because mining and the industry is international in nature and operations, some British Commonwealth cases will appear in various topics. If the case is of interest to the reader, further inquiry at a law library may be made through use of the case's style and citation given. "Style" refers to the name of the litigating parties. "Citation" refers to the law publication in which the case and decision may be found, as well as the jurisdiction and court of decision. Citation of cases from the United States and British Commonwealth nations is explained under Case Citation Explanation. Space and time limit exhaustive treatment of subjects and covering all geographic and jurisdictional areas. This chapter is intended as a broad outline and is based on the author's master's thesis at the University of Missouri-Rolla, 1992. The following Case Citation Explanation provides guidance on formatting of citations.

Jan 1, 1994

This report summarizes a study conducted by The Service Bureau Corporation for the Bureau of Mines. Evaluations reflected herein are the result of an independent investigation by The Service Bureau Corporation of methane considerations during coal mining. The study is oriented toward a systematic analysis of methane control problems during coal mining. Throughout this study an attempt has been made to ensure considerations consistent with the recently enacted Federal Coal Mine Health and Safety Act of 1969. References to reports by The Bureau of Mines and others are made for the purposes of establishing identification between the evaluations contained in this report and on-going research efforts.

Jan 1, 1970

By L. You

Theoretical and analytical analyses of three mitigative measures- plane fitting method, trenching, and tension cable led to the development of a total protection plan to eliminate or reduce damages to the residential structures subjected to surface movements caused by underground longwall mining. The protection plan was applied to twelve residential houses and two external garages. The success rate is overwhelming. This paper describes the methods employed for protection and results of those case studies.

Jan 1, 1986

By Edward L. McHugh

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 5-acre Zwagg Island Wilderness Study Area (OR-12-14) in order to evaluate its identified mineral resources. The study area is located in Curry County, OR, immediately west of Brookings. There is no evidence of mining activity on or near Zwagg Island, and no mineral resources were identified. The steep-sided, flat-topped island is normally accessible from the mainland by way of a sandy beach. The island consists mainly of marine sandstone, mudstone, and conglomerate of the Jurassic Dothan Formation. Dothan Formation sandstone has been used locally as construction material. Rock along the coast has also been used for construction of jetties to improve harbor access; additional work has been proposed at the port of Brookings. Although suitable for other construction uses, stone from Zwagg Island would probably not meet physical requirements for jetty stone. Development of a stone resource on the island is unlikely.

Jan 1, 1987

By Scott A. Stebbins

This Bureau of Mines publication presents a method for estimating capital and operating costs associated with the exploration, mining, and processing of placer deposits. To ensure representative cost estimates, operational parameters for placering equipment and basic principles of placer mining techniques are detailed.

Jan 1, 1987

By Holler W. Walter Enrique

Dado que las entidades comercializadoras de concentración y minerales exigen que los productos mineros sean limpios, la organización minera diseñó y estudió una tecnología para la eliminación del Hg, donde la fabricación y montaje de los hornos gemelos circulares permite el lavado y recuperación del material sólido. En este sentido, el presente texto describe el proceso de desmercurización de ciertos minerales a través del uso de hornos metalúrgicos que liberan el Hg, y lo descargan automáticamente del proceso en el que se encuentra.

Nov 8, 1984

By Loren R. Anderson

A probabilistic slope stability computer model was developed at Utah State University and independently evaluated by CH2M Hill Consulting Engineers as a design and analysis tool. Volume I of this report describes the model and Volumes III and IV are users manuals for the computer programs. This volume (Volume II) constitutes the report by the CH2M Hill. It includes a description of a field investigation and stability analysis of an existing tailings dam. Based on the results of the analysis, the tailings dam was evaluated for redesign using probabilistic considerations. Conclusions are made regarding the usefulness of the model as a design tool.

Jan 1, 1982