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By K. O. Bennington

The thermodynamic properties of two manganese silicates, pyroxmangite and fowlerite (zincian rhodonite), were experimentally determined by the Bureau of Mines. The standard enthalpies of formation were determined by hydrofluoric acid (HF) solution calorimetry, the low-temperature heat capacities by adiabatic calorimetry, and the high-temperature heat capacities by differential scanning calorimetry over the range 322 to 1,372 K. Data for the standard enthalpy of formation (AH298), the derived standard entropy (S298), and the standard Gibbs energy of formation (AGf 298) are as follows: Pyroxmangite [(Mn0.9554Cao,0446)(Si03)J- AHf298 319.668±0.46 kcal/mol AH298 (from oxides)... -7.215±0.11 kcal/mol 5295 23.785±0.048 cal/(mol'K) AGf298 -301.190±7.96 kcal/mol Fowlerite [(Mno.7o3Zno.0884Ca0.2086)(Sio3)]--AHf298 ?... -329.914±0.419 kcal/mol AH298 (from oxides)... -8.400±0.104 kcal/mol 5598 21.949±0.059 cal/(mol-K) AGf298 -310.716±7.99 kcal/mol These experimentally determined values were combined with data from the literature to calculate the Gibbs energies and equilibrium constants of formation over the temperature range of the measurements. Standard enthalpies, Gibbs energies, and equilibrium constants of formation are given as a function of temperature from both the elements and the constituent oxides.

Jan 1, 1987

By O. C. Ralston

Natural or artificial manganese dioxide of a grade pure enough to be satisfactory as depolarizer for dry cells has never been available in large supply simultaneously with being available in desired quality . The Second World War called for more of it than ever . A supply of natural material from the Gold Coast was ample for the war and was not completely exhausted . Whereas the crystal form of the manganese oxide was not recognized as a matter of importance until the war came , it is now known that gamma MnO2 is a desirable form and that pyrolusite , once thought acceptable , is not the best mineral . The following paper is a translation of an internal company report filed at the Bitterfeld office of the I. G. Farbenindustrie A.G. by Dr. Peter Marx in 1933 , just a year after G. W. Nichols had published in the Transactions of the American Electrochemical Society a study of making anodic manganese dioxide from solutions of manganous sulfate . The I. G. experiments were made to confirm the American work and were also extended to a larger scale . Only chemical purity was considered , and no mention is made of crystal form . The report adds to the knowledge submitted by Nichols but has not been previously available to the general public . Believing it of value to the United States industry , a translation has been made .

May 1, 1948

By D. H. Chambers, Arnold M. Lansche

Electro recovery by amalgam methods was investigated to determine the feasibility of recovering pure cadmium from cadmium sponge produced during purification of zinc electrolyte at electrolytic zinc plants . Actual material used in this work was air- oxidized cadmium sponge . An acid rinse and zinc displacement technique was developed to amalgamate this oxidized cadmium . ( In - plant use of the recovery process would probably not require this step because of the fresh state of the sponge . ) Zinc was completely removed from amalgamated sponge by selective oxidation with air . Zinc - free cadmium amalgam was circulated by an electromagnetic pump through an electrolytic cell where cadmium of 99.9+ percent purity was electrodeposited onto a rotating aluminum cathode . Polarographic methods were developed for determining cadmium and zinc in mercury and in sulfuric acid solution .

Jan 1, 1964

By H. C. Miller

The removal of the mud sheaths that are deposited against the faces of productive oil sands during rotary drilling is one of the important problems confronting operators, especially in semidepleted fields where formation pressures are low. Unless the mud sheaths behind the perforated oil strings and, liners are removed and the sands exposed, oil cannot enter the wells. Consequently much oil that otherwise eight be produced from low-pressure sands is trapped and never recovered. Various types of perforation washers, down swabs, and agitators are used at present for breaking down the mud sheaths and. removing the disintegrated clay particles from wells after the perforated pipes have been inserted. Mechanical methods for removing mud sheaths are quite satisfactory, but prompted by tie request of certain operators in the California oil fields Bureau of Mines engineers have conducted a series of laboratory tests with the view of developing a chemical method for removing mud sheaths in oil wells that will be applicable to field conditions.

Jan 1, 1934

By M. J. Ferrante

A process was investigated for preparing Specification-grade nickel (containing less than 1 percent cobalt) by stripping it electrolytically from a nickel sulfate-boric acid solution and using the stripped electrolyte for the preferential dissolution of nickel from basic carbonates of nickel and cobalt. The basic carbonates were produced at the plant at Nicaro, Cuba, owned by the U.S. Government. Determination of the optimum conditions for deposition of Specification-grade nickel indicated that the upper limit of cobalt concentration was 0.1 gram per liter. The pH, temperature, and concentrations of nickel and boric acid in the electrolyte were not critical. An aluminum cathode and two lead anodes were used at a cathode current density of 1.2 amperes per square decimeter.

Jan 1, 1959

Federal Regulations require MESA to regulate the exposure of workers to inhalation hazards in the surface work areas of coal mining and processing operations. (1) The purposes of this study are listed below: 1. Determination of candidate inhalation contaminants for surface work areas of coal mining and processing operations. 2. Selection of appropriate sampling and analytical methods. 3. Performance of qualitative surveys of 56 representative coal mining and processing facilities. 4. Preparation of handbook to provide guidance for inspectors sampling for these contaminants. This report describes the work which was done to accumulate the information which was used in preparing the inspector's handbook. Specifically, this report contains descriptions of the surveys which were performed, analytical results obtained from these surveys, findings and conclusions, and recommendations for additional research.

Jan 1, 1975

By Jr. Flynn

This U.S. Bureau of Mines publication is a compilation of fundamental cyanide chemistry data obtained through review of the scientific literature. It includes information on thermodynamics and chemical equilibria, ultraviolet-visible and infrared spectra, and the chemistry and photochemistry of cyanide, chemical species derived from cyanide, and metal cyanide species. It also includes guidance on the use of the data for solving practical problems in precious metals applications. This publication is intended mainly for use as a reference by personnel in the precious metals industry and regulatory agencies, and other cyanide users, to provide comprehensive information on cyanide chemistry. The document should assist in the formulation of effective policies for cyanide control in the construction, operation, and closure phases of precious metals mining and metallurgical operations. In addition, the data in this publication will be useful in other contexts, such as dealing with industrial cyanide usage, cyanide-containing wastes and associated environmental problems.

Jan 1, 1995

By M. Hayashi

The Bureau of Mines conducted laboratory studies on Idaho mudstones to examine techniques for extracting vanadium. Recovery of vanadium from low-grade sources could contribute to future vanadium production and reduce reliance on imports. An Idaho mudstone surface sample containing 0.30 pct V205 and an underground sample containing 0.21 pct V205 were used in the extraction tests. Leaching of the surface sample for 18 h at 800 C with the addition of up to 1,000 lb/ton H2S04 recovered 70 pct of the vanadium. How-ever, leaching of the underground sample under the same conditions re-covered only 47 pct. By adding 15 wt pct NaCl and roasting the samples at 7500 C for 2 h, followed by leaching with 800 lb/ton H2S04, vanadium extractions were increased to 78 pct from the surface sample and 83 pct from the underground sample. Water leaching of samples roasted at 7500 C for 4 h with a 25-wt-pct NaCI addition yielded about 60 pct of the vanadium from both surface and underground samples. Autoclave leaching at 2000 C for 3 h with 1,000 Ib/ton H2S04 extracted 97 pct of the vanadium from the surface sample and 86 pct from the underground sample. An exploratory solvent extraction investigation to purify and concentrate vanadium in the leach solution using several organic reagents was also conducted.

Jan 1, 1985

By W. T. Benson

The Bureau of Mines has undertaken investigations to examine selected deposits of beryllium throughout the United States. The beryllium deposit about 6 miles southeast of Lone Pine in the Owens Valley region of Inyo County, Calif., was among those selected for study. In 1960, field work was conducted on the Inyo Beryl claim to determine the extent and character of the beryl-bearing deposit. This report describes the work that was done. In the area investigated, the beryl occurs disseminated in granite and limestone and as stringers. Apparently, the stringers are related to nearby pegmatite dikes, inasmuch as some appear to contain fine-Grained pegmatite. Granitic rocks enclose most of the stringers, which occur as fracture fillings, ranging from thin seams to 4 inches in thickness. The stringers are of muscovite, quartz, albite, and beryl. Some also include epidote and fluorite. For the most part, they are widely spaced. Therefore, mining of substantial tonnages averaging better than 0.2 percent beryl does not appear feasible.

Jan 1, 1962

By Oliver Bowles

"Rhodesian asbestos is of high quality and is much in demand by American consumers. Production in Rhodesia was first reported in 1909. The production for this and each succeeding year is shown in the following table:The serious curtailment in production for the years 1912 and 1913 was occasioned by transportation difficulties. In 1914 a railway was projected to Victoria and thereafter production increased greatly. Up to 1916 asbestos was obtained,from the Victoria district only, but thereafter the Bulwayo district became an important,producer with minor quantities from Gwelo.In the Bulawayo district the productive area is about 2 1/2 miles long, with Shebanie mine at the north-west end, the Nil Desperandum at the south end, and the Birthday claims between them."

Oct 1, 1920

By Joseph C. Zelanko, Christopher Mark

During August, two eastern Kentucky coal miners died in a roof fall during retreat mining operations. They had just finished extracting one pillar block and were moving to the next one when the intersection they were standing in collapsed. Regrettably, this was not an isolated incident. Since the end of 2000, there have been 28 ground fall fatalities in U.S. coal mines. Of these, 10 occurred during pillar recovery operations. Although pillar recovery has been associated with about one third of recent ground fall fatalities, it accounts for only about 10% of U.S. underground coal production. Statistically, a coal miner engaged in pillar recovery is several times more likely to be killed in a ground fall than a miner on an advancing section of a longwall. Pillar recovery is dangerous because it creates an inherently unstable situation. Once the pillars are extracted, the roof is expected to cave. Safe pillar recovery does not mean preventing roof collapse, it means ensuring that it only occurs after the miners have completed their work and have left the area. Fortunately, there are a number of proven techniques that can greatty reduce the hazards of pillar recovery. These include better mine planning, improved roof support, and safer work procedures. The goal of this article is to describe the most significant "risk factors" associated with pillar recovery, and prescribe control techniques that, taken together, can reduce the overall risk to miners. The conclusions are based on extensive studies conducted by the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) that have included detailed analysis of every fatal retreat mining incident since 1992 (25 incidents resulting in 30 fatalities). Risk reduction strategies for pillar recovery can be divided into three main groups: Global Stability: Prevention of section- wide pillar failure; Local Stability: Prevention of roof falls in the working area; and Work procedures and worker location: Minimizing exposure to hazardous areas.

By J. S. Berber

Bastnasite is a natural fluocarbonate of the cerium group and affords an abundant and high-grade source of the lighter rare-earth elements. As part of a broad research program in rare-earth element technology, the Federal Bureau of Mines directed extensive experimental work to separating and purifying the rare-earth elements in bastnasite. By the use of a combination of techniques--classical chemical, ion exchange, and solvent extraction--the processing of a bastnasite concentrate to obtain the individual rare-earth elements, or groups of elements, was accomplished. A bastnasite concentrate, containing about 60 percent rare-earth oxides, was sulfated with concentrated sulfuric acid to eliminate the carbon dioxide, fluorine, and silica. Calcination at 1,200° F. made the gangue matter insoluble, thus permitting the separation of the soluble rare-earth sulfates. Essentially 100 percent of the rare-earth elements were recovered by this procedure. Since the rare-earth sulfate solution contained only trace amounts of nonrare-earth elements, subsequent separation procedures were simplified.

Jan 1, 1960

By Thomas Varley

"During the past few years, since flotation has become the paramount treatment method for most all kinds of ores, the Bureau has gathered the data on consumption of reagents used in the flotation treatment. The first report was issued in 1916. A brief review of such reports shows the progress made in the art of flotation, and each year brings forth development of new reagents or combinations of reagents that seem sure to survive, but research and progress spell their defeat, if not by entire elimination, at least subjects them to considerable modification. Fortunately, close cooperation between the Bureau and the operators has been the means of an exchange of ideas in research work, and the development, in plant practice, of such research work on a commercial basis, is one of the outstanding features in milling today.In past years flotation has been referred to generally as ""oil flotation""— today it might be more properly called ""chemical flotatioin"" Minerals can be floated today without oil. Chemicals alone will do the work, showing how little was truly known about the process heretofore. The term ""regents as used herein, includes both chemicals and oils. The total pounds of oils and reagents consumed during the year was greater than shown in the 1925 report. The 1926 total was 201,711,795 pounds as compared with 81,688,967 pounds for 1925. The equivalent in pounds of reagent use& per ton of ore for 1926 was 3.933 as compared with 1.7972 for 1925. This increase is due largely to the amount of lime which is added in the alkaline circuits particularly in the mills treating coppers ores, which accounts for the larger tonnages."

Jan 1, 1928

This surveillance report summarizes data on work-related fatal and nonfatal injuries, illnesses, and hazardous exposures in the mining industry for the 10-year period 1986-1995. The term "surveillance," as used in public health, may be new to many readers of this report. With regard to occupational safety and health, the goal of surveillance is to describe the occurrence of work-related injuries, illnesses, and known hazardous exposures; to identify new hazards that may occur due to the introduction of new technology or other factors; and to assess the effects of preventive measures designed to improve worker safety and health. Surveillance provides an overall picture, which can be used to focus resources on areas most in need of prevention programs or further research. Surveillance generally requires the use of multiple sources of data, all of which have their own strengths and limitations. Surveillance in the U. S. mining industry is complicated by the fact that U.S. national data systems that provide information on mining are based on two different definitions of the mining industry. One is established by the Mine Safety and Health Administration (MSHA), the other by the Standard Industrial Classification (SIC) System [Office of Management and Budget 1987] and the 1980 U. S. Bureau of the Census (BOC) Classification System [U.S. Bureau of the Census 1982]. The mining industry as defined by MSHA is based on the regulatory jurisdiction of that agency. Reporting requirements for injuries, illnesses, and workplace exposures are stipulated under the Federal Coal Mine Health and Safety Act of 1969 and the Federal Mine Safety and Health Amendments Act of 1977. Of note is that the oil and gas extraction industry falls outside of MSHA jurisdiction. The Occupational Safety and Health Administration (OSHA) was charged with enforcement in the oil and gas industry under the Occupational Safety and Health Act of 1970. Under the SIC, the definition of mining covers the extraction of naturally occurring minerals, including liquids (petroleum), gases (natural gas) and solids (coal, metal, and nonmetallic minerals). Exploration and development of mineral properties are also included in the SIC definition of the mining industry. The SIC was developed by the Office of Management and Budget for use in classifying establishments based on the type of economic activity in which they are engaged and serves as the industry classification standard for all establishment based Federal economic statistics. This classification is important for occupational safety and health surveillance because it also serves as the industry classification system for all data on work-related injuries and illnesses collected by the U.S. Bureau of Labor Statistics (BLS). The U.S. Bureau of the Census uses an industry coding scheme similar to that used by the SIC. For the mining industry, the categorization is identical in both systems. Death certificate data made available by the National Center for Health Statistics (NCHS) are categorized under this system. Death certificate data are particularly important for surveillance of mortality from work-related illnesses. Key differences between the SIC/BOC categorization system and the MSHA system can be summarized as follows: • MSHA excludes the oil and gas industry, which is classified as part of the mining industry under SIC/BOC. • MSHA excludes work that is done off of mine property; work off of mine property is included under SIC/BOC if it is performed by an establishment falling into one of the SIC/BOC mining industry codes. • MSHA includes mine-associated mills and processing plants; these are classified under the manufacturing industry, rather than mining, according to the SIC/BOC coding structure. Since the data collected by MSHA and the data collected by BLS and NCHS using the SIC/BOC classification system are both important sources of information on the mining industry and in many cases serve different purposes, data from both systems are presented in this report. In general, data using the SIC/BOC system are comparable across U.S. industries and should be used when comparing mining to other U.S. industries. Much of the data in this report are presented in the form of frequencies or rates. A frequency provides only a count of the number of cases without providing any information about the risk of occurrence. Rates provide an estimate of the risk of injury or illness. The reader is cautioned, however, that rates based on small numbers can be unstable; thus, any inferences should be drawn with care. In this report, no rates are presented for groups in which there were fewer than three cases. The incidence of most injury and illness conditions differs by age, sex, and race. For this reason, data in many surveillance reports are adjusted for these demographic factors. It was not possible to do this for most of the rates in this report because information on demographics was not available. With the exception of the proportionate mortality ratios (PMRs), all data presented are unadjusted. A detailed account of the sources of data is in appendix A. The methods used in data selection and analysis are described in appendix B.

Jan 5, 2000

By D. W. Bridges

Solvent extraction has become important in recent years as a unit process in extractive metallurgy. The flexibility and simplicity of the technique have attracted widespread attention, and numerous papers describing actual and projected metallurgical applications have been published. However, differences in terminology, procedure, objectives, and standards, as reflected in reports by different operators and investigators, have sometimes made appraisals and comparisons difficult. Consequently, a need appeared for n series of basic reports on the subject. This Bureau of Mines Information Circular is the first of such a series. It deals with the status of solvent extraction in metallurgy, as well as with the rudiments and terminology of the unit operation. In analytical chemistry, extraction of molecular species from aqueous media by immiscible organic solvents has been used for many years to separate and determine chemical elements (61).4 Complex chlorides of iron and other metals are readily soluble in ethers and ketones, as are the nitrates of uranium and thorium. Most metals are extractable as complex salts of some organic reagent, such as dithizone, 8-hydroxyquinoline, or cupferron.

Jan 1, 1962

By D. J. MacDonald

The Bureau of Mines investigated two alternative methods for treating a zirconium-bearing chloride-sulfate strip liquor to obtain reactor-grade Zr02. One method involves neutralization with NH3 and the other hydrothermal precipitation. The strip liquor was derived from zircon sand by a Bureau of Mines method for separating zirconium and hafnium via solvent extraction with a tertiary amine. Neutralization with NH3 to precipitate hydrous zirconium oxide required 0.9 to 1.1 g NH3 per gram of zirconium. The NH3 can be recovered for recycle. Zr02 that met reactor-grade specifications was produced by precipitation with NH3? Hydrothermal precipitation of Zr02 from strip liquor required that the solution be maintained at 2600 C and 680 psi for 10 min and in a non-corrodible pressure vessel. In bench-scale experiments both methods gave-zirconium recoveries greater than 99 pct.

Jan 1, 1984

By H. L. Gilbert

Zircon sand may be reacted with sodium hydroxide at 600° C. to form sodium zirconate and sodium silicate. Sodium zirconate is water insoluble and so may be washed free of sodium silicate. The sodium zirconate may then be converted to zirconyl chloride by the action of hydrochloric acid and the zirconyl chloride crystals separated by cooling the solution. This approach produces zirconyl chloride of satisfactory purity with less cost than is involved in buying anhydrous zirconium chloride and converting it. A proposed design for a plant is given, INTRODUCTION This work was conducted by the Rare Metals Branch as a part of research on zirconium at the Bureau of Mines Northwest Electrodevelopment Laboratories, Albany, Oreg., under the guidance of S. M. Shelton, Regional Director. The work was supervised by W. W. Stephens, head of the Rare Metals Branch (now with Carborundum Metals Corp.).

Jan 1, 1954

By W. A. Calhoun

This investigation of low-grade bauxites as potential sources of aluminum by caustic desilication and alumina extraction was undertaken by the Bureau of Mines to develop extractive methods for winning alumina from domestic deposits of low-grade bauxites. This report is the second of a series covering the work by the Bureau of Mines' Rolla, Mo., and Bauxite, Ark., laboratories. The first report published in the Journal of Metals, December 1951,3/ and dealt with kaolin and halloysite. The present investigation is concerned with low-grade bauxites only. The purpose of these investigations is to increase the domestic supply of aluminum ores. With eventual depletion of high-grade deposits, aluminous materials, such as low-grade bauxite, clays, shales, and high-iron laterites, will become our principal domestic sources of aluminum. The development of extractive processes for winning alumina from these low-grade materials is one of the many national security measures undertaken by the Bureau of Mines. A method has-been developed in the laboratory for successfully treating high-silica bauxites from domestic deposits. In this process the bauxite was calcined at 980° C. to form amorphous silica and alumina. The calcine was then leached by percolation with 15-percent sodium hydroxide solution at 940 to 96° C., removing 67 to 77 percent of the silica with a loss of 4.1 to 5.0 percent of the alumina. The sodium hydroxide in the spent liquor used in desilication was 95 percent recoverable, and comparable desilication results were obtained with 100-percent reclaimed liquor, The indicated cost of reagents, for sodium hydroxide and lime used in the desilication and regenera¬tion of spent liquor, was about $4.00 per ton of calcine treated.

Jan 1, 1954

By P. T. Brooks

This Bureau of Mines study describes a process for recovering nickel, cobalt, molybdenum, and chromium contained in complex waste superalloy grindings that, for lack of an economical domestic recovery process, are being largely marketed abroad. The process, devised by laboratory scale operations, includes scrap preparation, dissolution of metallics in hot chlorinated acidic liquor, carbon adsorption, three successive solvent extraction separations, and selective chemical precipitations. Nearly 90 percent of the nickel, cobalt, molybdenum, and chromium were separated and recovered as oxides, carbonates, and basic sulfate products.

Jan 1, 1969

By M. Copeland

Phase relations of gadolinium alloyed, up to 40 weight-percent (wt pct), with AISI 304-type stainless steel were established. Body-and face-centered cubic iron-rich solid solution phases and several intermetallic gadolinium-containing compounds of variable composition that approximated the formulas Fe9Gd, Ni7Gd2, Ni3Gd, Fe2Gd, NiGd, and NiGd3 were identified. The intermetallic phases Fe9Gd and Ni7Gd2 were noted to melt at about 1,080° C at about 0 to 2 wt pct gadolinium. The melting temperature of Fe9Gd increased with increas-ing gadolinium content to a plateau at about 1,230°C and 30 wt pct gadolinium, and the melting point of Ni7Gd2 decreased to a plateau at 900° C and 30 wt pct gadolinium where Ni3Gd, NiGd, and Fe2Gd coexist. Body-centered cubic iron solid solution was stable from 1 to 2 wt pct gadolinium to higher contents, 30 wt pct gadolinium or possibly more, and face-centered cubic iron up to 12 wt pct gadolinium below 1,200° C. The stability of these phases above 1,200° C was not resolved except for the mel points. A limited number of fabrication variables as well as mechanical and corrosion properties of alloys containing up to 5 wt pct gadolinium were studied. Equilibrating and forming operations were best conducted at about 940° to 1,080° C. Some variability in the yield and tensile strengths of alloys was noted; however, there was a continual decrease in ductility and impact resistance with increasing gadolinium contents. The resistance of gadolinium alloys to corrosion in water at 354° C was about the same as stainless steel.

Jan 1, 1965