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By Howard M. Stainer

Published X-ray mass absorption coefficients were compiled and tabulated. These coefficients are required for various X-ray analytical techniques. Values obtained from 28 authors are listed for 87 elements with both experimental and calculated points included; the wavelengths range from 4.01 to 68 A. Representative graphs are presented for six elements (lithium, nitrogen, iron, silver, holmium, and uranium. A 37-item supplementary bibliography is also included.

Jan 1, 1963

By Howard M. Stainer

Published X-ray mass absorption coefficients were compiled and tabulated. These coefficients are required for various X-ray analytical techniques. Values obtained from 28 authors are listed for 87 elements with both experimental and calculated points included; the wavelengths range from ~0.01 to 68 A. Representative graphs are presented for six elements (lithium, nitrogen, iron, silver, holmium, and uranium. A 37-item supplementary bibliography is also included.

Jan 1, 1963

By N. Arbiter, C. C. Harris

The economic advantages of large diameter ball mills can be compromised by unexpected capacity limiting conditions. These arise because media rotational flow to ore axial flow ratios, and the number of mill revolutions that ore is subjected to during residence, are both inversely proportional to mill diameter. Because of this, mixing efficiency and grinding kinetics may decrease and become capacity limiting when mill diameters reach a critical range. There are two possible scale-up problems involved in the design and use of mineral processing machinery: • Selecting the size and operating conditions for available larger equipment, to insure that operating results will match those obtained with smaller units; or •Extending the size ranges of equipment beyond existing limits. Previous research at Columbia University into flotation machine hydrodynamics has demonstrated the importance in scale-up of internal flow relationships; these perform a similar role in grinding (Arbiter and Harris, 1980).

Jan 1, 1982

Jan 1, 1967

By Forrest T. Moyer

To keep the mineral and allied industries informed of trend: in the causes of accidents and to point out the need for corrective measures, the Bureau of Mines collects, analyzes, and publishes, periodically health and safety statistics. This report includes data for 1961 on injury experience, with related employment statistics, at coal mines in the United States. These data are presented in tabular form under the following headings: General Injury Experience Tables 1 to 6: Current data on number of injuries, degree of injury, frequency and severity rates, average severity, and related employment and production data by work location.

Jan 1, 1963

By John C. Machisak

The National Safety Competition is sponsored and conducted annually by the Bureau of Mines, U.S. Department of the Interior, to give greater impetus to the building of programs safeguarding the employees of the mineral industries from disabling work injuries. The results of the 1960 National Safety Competition are presented in this publication. Mines and quarries that were awarded the Sentinels of Safety trophy for the best safety record in their competitive group and those mineral operations that ranked second, third, fourth, and fifth in the competition are listed with a summary of their achievements in preventing disabling work injuries. In addition, this publication presents statistical data on disabling work-injury experience in all other mines and quarries participating in the annual competitions.

Jan 1, 1962

By E. G. Davis

As a result of interest by the U.S. Department of Energy, the Bureau of Mines conducted studies on comminution of bituminous coal to the 2-um particle size range using the Bureau-developed turbomill. Both "plant grind" size (80 pct minus 75 um) and microsize (minus 10 um) coal can be produced in a single step with the Bureau's turbomill. In 15 min, minus 2.4-mm coal milled in water with steel shot was reduced tc 65 pct minus 75 m and 26 pct minus 2 m, with an energy requirement of 139 kW^h/mt coal. Plant-grind size coal milled in water, with Ottawa sand as the milling medium, was reduced to more than 45 pct minus 2 m in 15 min, at 175 kW?h/mt. Plant-grind coal milled with steel shot was reduced to 57 pct minus 2 um in 15 min, at 138 kW?h/mt. When diesel fuel was substituted for water, the milling of the coal was less effective and less energy efficient. Keeping the pulp dispersed was critical. Without an effective dispersant, the slurry became very viscous with increased milling time, resulting in higher energy requirements, low heat dissipation, and poor grinding efficiency.

Jan 1, 1987

By P. J. Baguley

The model has been developed on the basis of the observation that the partitioning behaviour of a particle is related to its calculated terminal velocity. It utilises a theoretical calculation of the terminal velocity of each particle class. This is then correlated with the observed partition data for a plant separator using empirically-derived functions of operating conditions which take into account effects such as bath turbulence, holes in drum lifters and feed arrangements. The model successfully decouples the effects of medium density and viscosity and is appropriate for any bath-type separator. The correlation between calculated terminal velocity and actual partitioning behaviour was established and modelled using data obtained from two Wemco drums treating Fe and Mn ores. The model can be used to predict the prevailing size-by-size partition curves and the separation (product grades/recoveries) given the washability of the feed and operating conditions. Simulations are used to show that, for the treatment of Fe ore, there is a maximum medium density beyond which product grades fall and that this maximum decreases as the proportion of magnetite in the medium increases. This is attributed to the dominant effect of viscosity at higher medium solids concentrations

Jun 18, 1905

By James L. Eirls

Tracor MBA under a contract to U.S. DOI Bureau of Mines designed, developed, fabricated and demonstrated a conveyor belt service machine. It is self-contained, battery powered, rubber tired and capable of handling, storing and transporting conveyor belting, wire rope and associated structures for sectional conveyor belts. While moving the tail section to its next position the machine discharges the belting, wire rope and belt structures. The belting is elevated and separated to provide for the insertion of the structures with minimum expended effort. A hydraulic system provides the power for steering, braking, winding or unwinding under controlled tension the belting and wire rope, operating a load-bed slat conveyor, raising, lowering and locking connection hitches and powering external hydraulic tools. Also, a pneumatic system is available to operate air impact tools. The service machine, with its present components can function in coal seams as thin as 48 inches, double wind conveyor belting 42 inches wide, 400 feet long, load or unload 3/4" wire rope on two separate reels and is controlled by two operators. A complete belt move using this machine requires only four workers. Successful underground demonstrations were conducted in coal mines located in West Virginia and Kentucky.

Jan 1, 1983

By C. J. Bise

One area of study for the Coal Mine Injury Analysis project was to illustrate how loss control can be used as a foundation for mine safety training. After an initial review of the principles of loss control, the instruments often used for worker/worksite appraisal, such as incident reporting, analysis, and investigation, workplace observation, worksite inspection, and safety audits and checklists were evaluated for their effectiveness. The findings were then applied to the continuous-miner worksite at several mines to modify the techniques for use in a highly dynamic man/machine work environment. Before the information gathered from the review of the various continuous-miner worksites was presented at the annual retraining sessions at five mines, a trainability analysis procedure was developed to separate training shortcomings from those problems resulting from improper equipment design or unsatisfactory working environments. Also, several microcomputer-based training programs were developed to aid in conveying the loss-control concepts to the trainees. Finally, the results from the implementation and evaluation of the loss-control-based training programs were documented, including the complete training script for one of the case-study mines. The procedures outlined in this study will aid mine training specialists in developing focused, pro-active accident-prevention strategies and training programs that are based on sound loss-control principles.

Jan 1, 1993

By Paul Russell, M. M. Kimberley, Erick F. Welland, Louis Cope, C. C. Mosher, William M. Shepard, William C. Larson, Graham Closs

Exploration activities in 1980 felt the effects of unstable economic conditions and oscillating metal prices. In the cyclical, boom-or-bust precious metals and uranium markets, precious metals activity flourished and uranium was definitely in a slump. By November last year, the price for vellowcake was down nearly $20 from two years earlier. Many mining and milling operations closed, particularly in Wyoming, New Mexico, and Colorado. Decreasing emphasis on nuclear power continued to impact the market, as did the Three Mile Island accident of 1979. Earlier forecasts estimated that 10 to 12 reactors would be ordered per year by US utilities throughout the 1980s, but current forecasts suggest that it may be 1983 or 1984, or even later, before any new US plants are ordered, according to Thomas A. Boyden, vice president of Nuclear Exchange Corp. "Without those new plants, the consumption loss to industry is 4 to 5 million pounds (1.8-2.3 kt) of uranium per year. The cumulative loss to the industry is currently estimated at 25 to 30 million pounds (11.3-13.6 kt)," Boyden said in a May 1980 presenta¬tion. Despite the plunging market, there were a few notable uranium explora¬tion programs: •Exxon expanded uranium exploration in New Mexico, where the company reportedly took preliminary steps toward acquiring mineral rights to a 22-km2 prospect, 19 km south of Santa Fe. • Mountain States Resources began the second phase of an exploratory drilling program on its Sinbad/ Solo prospect in Utah. • Also in Utah, Cotter Corp. drilled its first exploratory hole in the Dirty Devil River district. Exploration for precious metals in 1980, however, appeared to tend toward the opposite extreme. High prices sparked near feverish searches in Alaska, California, Colorado, and Nevada. Numerous mines abandoned years ago were revived with some signs of success. Significant gold finds were reported in California and Nevada: • Homestake Mining Co. announced a gold discovery in California estimated to contain over 5 Mt with an average grade of about 5.8 g/t. Because the deposit consists of finely disseminated particles not visible to the eye, many speculate that prospectors bypassed the area during the 1849 California gold rush. • Newmont Mining Corp. discovered two gold ore bodies-Maggie Creek and Gold Quarry. Maggie Creek reportedly contains an estimated 13.7 t of gold in 4.3 Mt of ore, and Gold Quarry contains about 31.1 t of gold in 9 Mt of low grade ore and 2.3 Mt of higher grade ore. Highlights of this year's exploration review include articles on the modest growth recorded in geophysical activity, technical developments in exploration geochemistry, the variety of new instruments being tested or made available for exploration, and a state-by-state exploration review for the year.

Jan 5, 1981

By P. Wittke-Gatterman

ABSTRACT: A three dimensional constitutive law for swelling rock is presented. It can be applied to the osmotic swelling of mudstone as well as to the swelling of rocks containing anhydrite. It describes the development of time-dependent strains and stresses due to swelling considering elastic and viskoplastic behaviour. Furthermore an anisotropic swelling behaviour can be considered. This constitutive model was implemented within a numerical computation program according to the finite element method and calibrated on the basis of the results of measurements in the investigation drift of the Freudenstein tunnel which is completely located in the unleached Gypsum Keuper. A parameter combination could be found which results in a good agreement between numerical solutions and results of measurements. Therewith an analysis procedure which enables the design of tunnels in swelling rock is available. ZUSAMMENFASSUNG: Im vorliegenden Beitrag wird ein dreidimensionales Quellgesetz vorgestellt, das nach derzeitigem Kenntnisstand sowohl auf das osmotische Quellen von Tonsteinen als auch auf das Quellen anhydrithaltiger Ton- beziehungsweise Schluffsteine anwendbar ist. Das Stoffgesetz wurde in ein Finite-Elemente-Programm implementiert und anhand von Meßergebnissen des im unausgelaugten Gipskeuper liegenden Untersuchungsstollens des Freudensteintunnels kalibriert. Es ist gelungen, eine Kennwertkombination zu finden, mit der alle Meßergebnisse gut beschrieben werden können. Damit steht ein Bemessungsverfahren für Tunnel in quellfähigem Gebirge zur Verfügung. RÉSUMÉ: Dans l'article présent un loi de gonflement à trois dimensions est présenté, qui peut être appliqué aussi bien au gonflement osmotique de l'argile compactée q'au gonflement de l'argile compactée ou du limon compacté contenant de l'anhydrite. Le loi de comportement était implémenté dans un programme numérique d'éléments finis et calibré avec des résultats de mesures de la galerie de recherche du tunnel de Freudenstein, situé dans le Keuper de gypse non lessivé. On est réussi à trouver une combinaison de paramètres avec laquelle tous les résultats de mesures peuvent être bien décrits. Par ce moyen, une méthode de dimensionnement existe pour des tunnels dans de la roche capable de gonfler.

Jan 1, 2003

In Bureau of Mines research on recycling chrome refractory wastes, used refractories from argon-oxygen decarburization and electric steelmaking furnaces were beneficiated, concentrates were reformed into briquets, and modulus of rupture tests were conducted at 1,350° C. The test results indicated that the beneficiated minus 6-mesh material could be used for producing magnesia-chrome refractories.

Jan 1, 1980

A new method, localized uniform conditioning (LUC), was proposed in 2006 for modelling grades of small blocks of ore when data spacing is too broad for their accurate modelling by the linear regression based techniques, such as kriging (Abzalov, 2006). It represents a modified uniform conditioning (UC) technique that calculates the grade distribution functions for the large panels. LUC uses partitioning of the panels onto the small blocks and then ranks them in increasing order of grade. Based on the block ranks, a single grade value can be deduced for each block from the UC model of the gradetonnage relationships of the corresponding panel. After being first presented in 2006, the LUC method has been implemented in ISATIS© (commercial software) and became one of the common approaches for grade estimation when data spacing is broad in comparison with the estimated block size. Several years of study on the LUC method and its application to different geological environments, have allowed identification of the strengths and weaknesses of the method, which are as follows: ? The method produces accurate grade-tonnage functions, which are in a good accordance with a volume-variance relationship principles ? An initial ranking of the selective mining unit (SMU) blocks can be made by direct kriging from the sparse data grid. Therefore, the LUC method can be particularly useful at the early stages of exploration and mining project evaluations when sparsely distributed data is often the only available information ? Accuracy of the local estimation depends on the SMU ranking techniques. When ranking performed by direct kriging of the SMU blocks their spatial distribution is approximate. When the variogram of the studied variable is characterized by a large nugget effect, the block ranks produced by kriging can significantly differ from their ?true? distribution ? Block ranking can be improved using auxiliary data, either geophysical or geochemical. This allows use of the LUC method for integrating different data sets. In particular, LUC can be used for grade control in open pits by integrating resource definition data (e.g. drill-hole assays) and blast-hole assays. The latter are used for the block ranking.

Jan 1, 2014

By W. Smith

The U.S. Bureau of Mines (USBM) is using laboratory and computer-based techniques to investigate the post- failure behavior of yielding pillars and pillar reinforcement techniques to control entry deformation. Poorly dimensioned yield pillars, can cause adverse ground conditions. Laboratory studies to evaluate various reinforcement techniques for controlling yield pillar deformation were conducted. A cracking and crushing model is used to evaluate potential tensile and compressive failure planes within pillars of various widths to assess the degree of yielding and stress redistribution. The use of an elasto-plastic model to evaluate the effect of various reinforcement on yield pillars is also discussed. These procedures effectively account for the residual pillar strength, important in yield pillar design.

Jan 1, 1995

The Application of Roasting Pretreatment for Antimonial Refractory Gold and Silver Ores

Sep 13, 2010

By James R. Boyle

The Bureau of Mines initiated a program to address short-and long-term objectives of wetlands restoration as a option for reclamation of lands mined for phosphate. The short-term objectives were to identify a suitable wetland test site, initiate an extensive premining monitoring plan, develop an acceptable mining plan, and recontour and revegetate the test site. These goals were accomplished using a unique combination of expertise provided by Federal and State agencies and private industry. A 6.5-ha forested wetland with an associated streambed was offered by private industry as the test site. A premining monitoring program was established and carried out from May 1982 to October 1983. A control site was established to determine ecological changes unrelated to mining. Clearing and mining began in October 1983 and was completed in April 1984. Grading and streambed restoration was completed in February 1986. Revegetation of the site was completed in February 1987. The program to meet the long-term objective of postmining monitoring is described.

Jan 1, 1988

By Tom Szaraz

Part of a major sewer expansion for the City of Columbus, Ohio. The Big Walnut Outfall Augmentation Sewer?Part II (BWOAS) consists of 13,200 feet of tunnel of 12-foot tunnel passing mainly through glacial deposits with a water head of up to 2 bar. A Lovat RME167SE was used to drive this tunnel with steel fiber reinforced precast segmental liner used for support. This paper will discuss the concepts for tunnel sup-port and TBM selection, the problems encountered with the TBM sealing systems and the solutions used to repair the machine.

By H. D. Kline

This paper is one of a series being prepared by the Bureau of Mines on methods, practices, and costs in various mining districts in the United States. The paper describes mining and ore recovery methods common to the Batesville manganese district, Independence County, Ark., and gives the costs of producing merchantable ore by three operators whose methods were more or less typical of those of many other local manganese producers. The operating costs reported were those of Leonard Baxter at mines on Brooks Hill for the calendar year 1958 and Arkansas Mining and Exploration Corp. at Section 16 mine and the Searcy group of mines and Miller-McGee Corp. at the Diener mine during the first 6 months of 1959. Manganese are was mined in the district as early as 1849 and almost continuously thereafter until August 1959, when termination of the Government's domestic manganese purchase program resulted in complete cessation of mining activity. During those years, production came from more than 189 mines and properties, of which only a few produced as much as 30,000 tons of merchantable ore.

Jan 1, 1962

CAPTAIN JOHN H. BALLAMY John H. Ballamy, Captain on the Regimental Staff of the 103d Engineers, was killed near Fismes, on August 9, 1918. Captain Ballamy was born at Plymouth, Pa., in 1886 and graduated from the High School of that town in 1903. In the following year he began work as a coal miner, and at the same time began the study of mining engineering in the evening and any other spare time. He continued this diligent and energetic practice for many years. For sixteen years he continued in the employment of the Delaware, Lackawanna & Western Railroad Company's coal mining department, first as a practical miner, next as rodman on the survey corps, of which he soon became chief, then draftsman and mining engineer in the company's office. In January, 1916, he was promoted to the position of district engineer in charge of mining engineering work. He became a member of this Institute in September, 1917. CAPTAIN JOHN H BALLAMY. Captain Ballamy's military experience began at the same time as his engineering practice. He was a charter member of Company A, Engineers, N. G. P., which was organized ten years ago. He saw service on the Mexican border as First Lieutenant of this Company, and remained in that position until November, 1916. In July, 1917, he was again called into service and was sent to Camp Hancock, Ga., with the 103d Regiment of Engineers. Before joining this regiment he attended a school for officers at Fort Sill, Okla., where he received special training in field fortifications. In December, 1917, he was commissioned Topographical Captain on the Regimental Staff, and in April, 1918, preceded his regiment by about six weeks to France, where he again attended an officers' training school. He rejoined his regiment on July 15, near Chateau Thierry and was killed near Fismes on August 9, 1918.

Jan 11, 1918