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By H. L. Bibbs, H. D. Snedden

"INTRODUCTION The use of beryllium and its alloys has increased rapidly during the last decade. Further expansion of its use is limited; in part, by lack of adequately developed ore reserves. The principal commercial beryllium mineral is beryl, which is found chiefly in pegmatites and produced for market as a byproduct of the mica and feldspar industries. The coarse beryl is mined selectively, sobbed and sorted by hand, and then sold without further beneficiation. The known reserves of coarse beryl are small. No method has been available for concentrating small disseminated beryl crystals, so ores of this type have not been mined or have been left on waste dumps. Disseminated ore in low-grade unmined areas and waste dumps on developed properties is a potential source of beryl, provided a method is developed for its beneficiation.Published literature on the concentration of beryl is lacking in detail or deals chiefly with tests on artificial mixtures of pure minerals, and procedures as given were not applicable to the beryl ores tested at the Salt Lake Station. The testing procedures described in this report are independent developments. By employing these procedures, beryl was satisfactorily con¬centrated from several run-of-mine and dump ores, although these ores wore low in grade and part of the contained beryl was finely crystalline and disseminated.Beryl, quartz, and feldspar, when ground to flotation sizes, are so alike in color and general appearance that they cannot he distinguished by visual observation. The progress of the work depended on rapid determination of the grade of test products by means of the petrographic microscope. Small samples of concentrates and tailings were often cut after each addition of reagents, dried, and examined under the microscope."

May 1, 1947

By Edward J. Caldwell

In 1930 the Bureau of Mines published a description3/ f the concentrating process of the Magma Copper Co. as it had been developed to that time and was then employed. The prevent paper revises the description to the end of 1943 and includes a description of the smelting processes. Data from the mild and smelter operations for, 1942 are given in tables 1 to 14, Billing costs are included, but it is not permissible to publish smelter costs.

Jan 1, 1944

By Margaret R. Egan

A series of experiments were undertaken by the Bureau of Mines to determine the emission products of several types of conveyor belting and other combustible materials found in mines. These experiments were conducted under intermediate-scale, simulated mine conditions to determine smoke characteristics and gas concentrations. From these determinations, heat-release rates, particle sizes, obscuration rates, combustion yields, and production constants were calculated. Three types of belts were investigated: chloroprene, also known as neoprene (NP); polyvinyl chloride (PVC); and styrene-butadiene rubber (SBR). The belts were designated as ignitable or self-extinguishing depending on the length of the burning time and the subsequent combustion products. Under these experimental conditions, the SBR belts were the easiest to ignite. The PVC and NP belts tended to self- extinguish within a few minutes after ignition, but were still capable of maintaining a brief flaming period. These conveyor belt combustion results are compared with previous analyses of wood, transformer fluid, and coal fires. Together they form a data base by which findings from future experiments with other mine combustibles can be compared.

Jan 1, 1988

By J. L. Holman

The Bureau of Mines is conducting research to improve technology for the recovery of strategic and critical metals, such as cobalt, nickel, and chromium, that are lost in bulk and particulate superalloy-type scrap because it has not been possible to process mixed contaminated scrap efficiently. The research approach involves melting and casting mixed superalloy scrap into soluble anodes for electrodeposition of Ni-Co alloys by controlled-potential electrolysis. The initial experimental results described in this report are from electrolytic tests us-ing alloy anodes cast from elemental nickel, cobalt, and chromium, the main constituent metals of superalloys. Baseline data and operating parameters are necessary for Ni-Co and Ni-Co-Cr alloys before detailed experiments can be conducted on the more complex superalloy scrap. This basic research assessed the effects of cathode potential, S04:CI electrolyte ratio, electrolyte pH, stirring rate, deposition time, cathode current density, and chromium concentration on cathode current efficiency, alloy deposit composition, and deposition potential at a cell temperature of 55° C.

Jan 1, 1985

By D. Bienstock

As part of the development of the hot-carbonate scrubbing process by the Bureau of Mines, the corrosion rates of steel in boiling solutions of potassium carbonate saturated with carbon dioxide and hydrogen sulfide were determined, and the effectiveness of various inhibitors was evaluated by Bureau researchers. The highly corrosive solution of carbonate saturated with carbon dioxide can be inhibited with a 0.2-percent concentration of either potassium chromate or sodium metavanadate. Solutions of carbonate saturated with carbon dioxide and hydrogen sulfide are mildly corrosive, 0.01 inch per year. Complete absence of corrosion is obtained with 0.2 percent sodium metavanadate or 0.15 percent vanadium pentoxide. Oxidizing inhibitors such as potassium chromate are destroyed in the alkaline sulfide mixture, N-alkyl trimethylene diamines, at a concentration of 0.1 percent, lower the corrosion rate to about 0.005. Sodium metasilicate, at a concentration of 0.6 percent, completely inhibits the corrosion but may deposit free silica in the system. Commercial cladding materials such as the epoxy coatings also prevent corrosion.

Jan 1, 1962

By Robert H. Peters

Groundfall accidents have been the leading cause of fatalities in the underground coal mining industry for many years. Statistics from the Mine Safety and Health Administration (MSHA) indicate that approximately half of the victims of these fatal accidents were in an area where no devices had been installed to support the mine roof. This report was prepared by the U.S. Bureau of Mines to provide guidance to operators of underground mines concerning the use of techniques that may help to keep miners from going under unsupported mine roof. The report is divided into two major sections. The first section reviews the findings from several areas of empirical research pertaining to strategies for convincing employees to avoid unsafe acts and/or adopt self-protective behaviors. The strategies are (1) incentives and feedback, (2) disciplinary actions, (3) training (primarily fear communications and behavioral modeling), and (4) nondirective techniques. This literature review has a broad focus and should be helpful in making decisions about how to encourage a wide variety of types of self-protective behaviors. The second major section of the report presents an analysis of each strategy's potential for keeping miners away from unsupported roof.

Jan 1, 1991

By L. A. Stewart

This paper describes all occurrences of barite in Arizona that were known or reported to the authors. The history, ownership, production, and geologic setting are discussed for most of the deposits. The uses and specifications of product grades are briefly discussed. Seventy-five deposits were examined in 9 of the 14 counties of the State. The descriptions are given under county headings. No occurrences were reported in the four northeastern counties of Coconino, Navajo, Apache, and Greenlee, nor in Santa Cruz in the southern part of the State. From about half of the deposits examined, 55 samples were taken; of these, 45 were for chemical analysis, and 8 larger samples, ranging from 100 to 350 pounds, for beneficiation tests. A 30-ton bulk sample was taken for pilot-plant tests. Bench-scale flotation tests of the eight samples employing several different procedures and reagent combinations yielded marketable-grade barite products with barite recoveries ranging from 60 to 97 percent. Five of the samples contained enough fluorspar to warrant its recovery. Acid-grade concentrates, which accounted for fluorspar recoveries of 45 to 70 percent, were obtained from three of these ores. Batch laboratory tests of a representative portion of the 30-ton bulk sample revealed that acid-grade fluorspar and high-grade barite concentrates could be recovered. Results of the laboratory and continuous pilot-plant tests of this ore will be presented in a separate report.

Jan 1, 1960

This report presents the results of reconnaissance-level investigations of the mill refuse disposal systems for 15 plants throw-heat the conterminous United States. The sites visited represent a cress section f the copper, iron, lead and zinc, and phosphate industries' practices in the field of fine-grained refuse disposal. The reconnaissance-level investigations were carried out to gather supplemental data to tae in-depth studies of Kennecott's Magma and Phelps Dodge's Morenci tailings deposits and Kennecott's Chino leaching dump. The various sites visited were classified according to the different systems and techniques used by the mining industry. The probable effects and relationships between site conditions and disposal methods were determined and evaluated to the extent feasible by a reconnaissance level investigation.

Jan 1, 1974

By Arthur E. Wells

"The present and possible future commercial production of potash from various sources in the United Status is discussed below under the following heads:1. Potash from the saline lakes.(a) Nebraska lakes.(b) California lakes.(c) Other lakes.2. Potash as by-product from the cement kilns.3. Potash as by-product from the iron blast furnace.4. Potash from silicate rocks.(a) Feldspathic material.(b) Leucite rocks of Wyoming..(c) Sericite slates of Georgia.(d) Glauconite (greensand) of New Jersey.5. Potash from Alunite.6. Potash from organic sources other than kelp.7. Potash from kelp.In this discussion very little more than passing reference, if any, will be given to those projects which up to date have been developed only slightly, if at all, beyond the small scale laboratory stage, or for the development of which there appears to be very little financial and technical backing at the present time. Nether or not many of these proposed projects have merit can be determined only by an actual operating demonstration.Generally speaking, the potash industry of the United States has been hardly more than marking time since the armistice. This is, largely due to the fact that the consumers of potash have been expecting that heavy shipments of foreign potash to the United States would be resumed soon at somewhere near the pre-war prices, and they have not seen owing domestic potash at present prices for many months. The result has been that domestic producers have been unable to sell their product at even cost and many producers of potash have been obliged to close down. Thu Nebraska lake plants were closed down in February. The California saline plants were operating at below capacity, and the only large alunite plant is closed down. Even the cement plants have little or no inducements to recover the potash being lost in their waste gases and the production is very small at present.This condition will doubtless continue until a definite policy is decided upon as to the future importation of potash salts from Germany and. France. If unrestricted importation is allowed at prices even 50% greater than in 1913, only a very few, if any, of the domestic projects will be in position to compete with the foreign potash immediately, and the present industry will probably greatly decline with little or no prospect for a future resumption of the industry."

Aug 1, 1919

By F. E. Joyce

This paper describes the development of a process for producing manganese and iron pellet concentrates from low-grade manganiferous iron ores of the Cuyuna range by a two-stage sulfatization-reduction roast. First, the manganese minerals (7.5 percent manganese) were converted to water-soluble manganese sulfate by roasting in sulfur oxide gases at 700° C, then, the hematitic iron minerals (31 percent iron) in the hot sulfatized are were reduced to magnetite with simulated reformed natural gas in the temperature range of 350° to 425° C. Batch tests were made in a 3-inch-ID by 6-inch-long, gas-heated, stainless steel retort, and continuous countercurrent experiments were performed in a 2-inch-ID by 10-foot-long, electrically heated shaft furnace. Manganese sulfate was removed from the roasted product by leaching with water, and over 90 percent of the manganese was recovered in an oxide product (65 percent manganese) obtained by precipitation, drying, and thelmal decomposition of the sulfate. An iron oxide concentrate (60 percent iron) with an iron recovery of 75 percent was obtained from the water-insoluble residue by magnetic separation.

Jan 1, 1973

By R. August Heindl

A process for recovering manganese from open-hearth steel-plant slags was investigated. The proposed method of accomplishing this is indicated by the flow diagram in figure 1. Mixtures of open-hearth, steel-plant flush slags and limestone, so proportioned as to have molar [CaO -3P205] ratios of approximately 2, were fired at approximately 2,400° F. in an oxidizing atmosphere and then cooled slowly. This treatment produced a clinker consisting principally of two solid phases comprised of (1) various combinations of the oxides of manganese, iron, aluminum, and magnesium, probably in spinel complexes, and (2) a dicalcium silicate phase, which contains the phosphorus. Reduction of these clinkers with hydrogen or with gaseous mixtures containing CO, CH4, and other hydrocarbons at about 1,300° F. formed manganous oxide as well as varying amounts of ferrous oxide and iron. Carbon monoxide and mixtures of hydrogen and carbon monoxide effectively reduced the clinkers but also gave higher proportions of soluble iron when the manganese was extracted from the reduced clinkers by leaching at about 80° F. with ammonium carbonate solutions containing 26 to 28 percent ammonia and 15 to 26 percent carbon dioxide. It is believed that the manganese is in solution as an ammonia-manganese complex. Concentrations of about 90 grams of manganese per liter were obtained by batch countercurrent procedures. By distilling 50 percent of the ammonia, the ammonia-manganese complex was decomposed, and approximately 90 percent of the manganese was precipitated as the carbonate with the simultaneous precipitation of 15 to 30 percent of the iron, the larger amounts of iron precipitating in the continuous tests. The manganese-iron ratio in the product could be increased either by recycling more manganese from the distillation to the extraction or by aerating the liquor to purge it of iron before, rather than after, the distillation step. Calcination of the pelletized manganese carbonate in an oxidizing stmosphere at 2,000° F. or above gave a final product, Mn304, resistant to crushing and apparently possessing the other physical properties essential in a ferromanganese blast-furnace feed.

Jan 1, 1955

By Albert L. Toenges, Theodore R. Jolley

"INTRODUCTION The construction of frame houses (fig. 1) in recent years instead of the conventional sod hut (igloo) (fig. 2) by the Eskimos in the villages along the Arctic Ocean has increased the demand for fuel in these villages. The frame houses, which are not insulated against extreme cold and are difficult to heat, are equipped with Goal stoves. The well-insulated sod huts were heated comfortably with whale-oil stoves. In some years whaling is Door, consequently there is a demand for solid fuel.The Eskimo villages usually are on the sand spits at the mouths of rivers and points of land near the best fishing and hunting grounds. These narrow necks of land usually are sand bars that are not underlain with coal, and coal must be transported to the villages. Lack of development of coal deposits in the Arctic has made it necessary to import coal from the States, generally from 'Washington, to supply these villages. This coal is imported by boat and is received once a year. Its cost is, high, and development of coal deposits in the Arctic to supply these native villages should result in a considerable saving to the Government-operated schools and hospitals as well as to the natives.Early traders attempted to establish coaling stations in the Arctic, and the Eskimos generally know where the coal deposits are situated. A. reconnaissance of a number of deposits in the Arctic was made in the summer of 1946 by engineers of the Coal Division, Fuels and Explosives Branch, Bureau of Mines, and this report describes the areas investigated and suggests plans for the development of some of these deposits."

Dec 1, 1947

By David C. Grant

In situ uranium mining offers the advantages of minimal environmental disturbance, low capital and operating costs, and reduced mining development time. It is becoming an increasingly attractive mining method for the recovery of uranium from secondary ore deposits. In order to better understand the process, a laboratory technique was developed and used to study and simulate both the chemical and physical phenomena occurring in ore bodies during in situ leaching. The laboratory simulation technique has been used to determine effects of leaching variables on permeability uranium recovery, and post-leach aquifer restoration. This report describes the simulation system and testing procedure in sufficient detail to allow the construction of the system, and to perform the desired leaching tests. With construction of such a system, in situ leaching of a given ore using various leach conditions can be evaluated relatively rapidly in the laboratory. Not only could optimum leach conditions be selected for existing ore bodies, but also exploitation of new ore bodies could be accelerated.

Jan 1, 1985

By H. B. Jensen

STUDY of the thermal-solution process was begun by treating crushed oil shale in a small autoclave at temperatures of 700° to 950° F. The effect of temperature, reaction time, type of solvent, and richness of shale upon the amount of organic matter that was removed from the oil shale was thus determined. Following this orientation work a semicontinuous, bench-scale apparatus was built so that heated solvent could be pumped through a bed of shale under elevated pressure, thus removing the converted organic matter from the spent shale. After some operating experience had been gained, a continuous unit was constructed. This permitted treating a slurry of shale oil and pulverized oil shale at about 300 p. s. i. and temperatures of 750° to 850° F. for various retention times. Considerable cracking and polymerization of the shale oil were found to take place during the process. In an attempt to prevent this, a study was made of extraction of the shale in batch-type autoclaves under high partial pressures of hydrogen at total gas pressures of as much as 4,300 p. s. i. at 850° F. The thermal-solution process was found to convert over 90 percent of the organic matter in oil shale to oil and gas. The highest yields of gas and oil obtained without hydrogen pressure were equivalent to 119 weight-percent of those obtained from the same shale by Fischer assay. With a high partial pressure of hydrogen, yields equivalent to 126 weight-percent of Fischer assay were obtained. However, the oil produced by thermal solution has a higher boiling range than that obtained by other retorting methods, particularly so if the thermal-solution process is used without a high partial pressure of hydrogen. Nondistillable oil (all benzene-soluble material that would not distill under 2 mm. Hg absolute pressure without cracking) equivalent to over 100 percent of the organic matter in the shale was obtained without hydrogen pressure in the system. When the process was carried out under hydrogen pressure, the yield of nondistillable oil amounted to 60 to 70 weight-percent of the organic matter. Part of this heavy material is formed partly by polymerization and condensation of the shale-oil solvent used. These reactions, as well as cracking of the solvent to form gas and a carbonaceous deposit on the shale, are unfavorable features of the process.

Jan 1, 1953

By T. T. Tomimatsu

[This Bureau of Mines paper investigates explores, and analyses the Corporate structure dynamics and Rancid role to evaluate the economic health of the U.S. copper producers. It highlights the Corporate policy options and measures of corporate profitability and suggests that a competitive domestic copper industry will exist in the future. The study highlights the activities of 14 selected major copper-producing companies, including their subsidiaries o affiliates, that were responsible for more than 95 percent of the total U.S. production in each of the years since 1969. The selected firms are hot all primarily in the business of producing copper. Several of the large producers are classified by the financial institutions as integrated oil and gas enterprises.]

Jan 1, 1980

By C. L. Karr

Researchers at the U.S. Bureau of Mines (USBM) have developed adaptive process control systems in which genetic algorithms (GA's) are used to augment fuzzy logic controllers (FLC's). GA's are search algorithms that rapidly locate near-optimum solutions to a wide spectrum of problems by loosely modeling the search procedures of natural genetics. FLC's are rule-based systems that efficiently manipulate a problem environment by modeling the "rule-of-thumb" strategy used in human decision-making. Together, GA's and FLC's include all of the capabilities necessary to produce powerful, efficient, and robust adaptive control systems. To perform efficiently, such control systems require a control element to manipulate the problem environment, an analysis element to recognize changes in the problem environment, and an adaptive element to adjust to the changes in the problem environment. The control system also employs a computer simulation of the problem environment. Details of an overall adaptive control system are discussed. A specific laboratory acid-base pH system is used to demonstrate the ideas presented; all results are from the physical laboratory system and not from a computer simulation.

Jan 1, 2010

By Leonard Obert

Between 1927 and 1957, sodium borate minerals were mined by underground methods in the Kramer District, Kern County, Calif. In 1957, surface mining methods were initiated, and during the next two or more decades it is probable that most of the production from the district will be obtained from open pits. However, part of this borate deposit is sufficiently deep that surface mining may not be economical and, hence, at some future date underground methods may again be employed. This report was prepared to document the underground mining methods employed in the district before 1957. The general geology of the district and the detailed geology of each of four mine sites are presented, together with a mineral and mechanical description of the ore and enveloping rock. The report also describes the stoping, extraction, pillar support, methods of artificial support, and other factors that affect the structural characteristics of these mines.

Jan 1, 1962

This appendix contains the list of equipment, their corresponding number and their specifications with the quotations from the vendors/ manufacturers who can supply this equipment. The listings are arranged by process plant areas.

Jan 1, 1979

By T. M. Barczak

Longwall tailgates in coal mines are often subject to severe mining induced loading and deformation. Innovative tailgate supports have been developed over the years to provide safe and economical access and a ventilation pathway at the tailgate. The support capacity and yield capabilities of the supports need to be matched to the loading imposed by the surrounding rock mass. The ground response curve can be used to represent the rock mass response to mining and its effect on support systems. The FLAC finite difference code was used to supplement field results by simulating a longwall tailgate and the associated ground response. The ground response curve is developed by modeling tailgate excavations with different internal support pressures and recording the resulting convergence. Ground response curves are developed for two typical longwalls operating in the Pittsburgh seam with weak and strong immediate roof. An additional model is presented in which the effect of weak overburden strata is simulated. The ground response is shown to be significantly affected by the strength of the immediate roof as well as the main roof. The importance of yield capacity of standing support is demonstrated. Gob height and compaction are found to affect the amount of convergence in the tailgate. The potential exists to develop site specific tailgate design curves by combining model results with field observations.

By H. S. Auvil

[The shrinkage of coke after formation is one of the variables that effects the net expansion of the change in both industrial and test ovens. Various test results5/ have been interpreted as indicating that cokes from certain coals shrink to a marked extent and that other cokes show very little shrinkage; but no comprehensive experimental study of the shrinkage of coke after its formation and of the factors influencing this shrinkage has come to the attention of the authors.]

Jan 1, 1940