Search Documents

By LeRoy R. Curwick

This Bureau of Mines report presents the results of a study conducted to assess the domestic availability of chromium from superalloy and cast heat- and corrosion-resistant alloy scrap material. Six alloy classes included in this survey were investment cast, hardfacing, and wrought nickel- and cobalt-base alloys, wrought nickel-iron-base alloys, and heat- and corrosion-resistant alloy castings. Data were collected for 1976 on metallic scrap generation, use patterns, and production practices for these alloy producing and using industries. A model was developed that allowed an assessment of the materials flow circuits within the industries that produce these alloys. The types, amounts, sources, secondary products, and ultimate destinations of chromium- containing metallic scrap for the six alloy classes were determined. Regarding the overall recycling efficiency of these alloy producing and using industries, of the 580.9 million pounds of scrap generated from these six alloy classes in 1976, about 72 percent (416.8 million pounds) was remelted by the same alloy-producing industries, about 18 percent (104.9 million pounds) was downgraded into stainless and low-alloy steels, about 3 percent (19.7 million pounds) was exported, and about 7 percent (39.5 million pounds) was lost through landfill or other disposal or service wastage. The lost material is primarily contaminated oxides for which recovery is currently uneconomic. However, the 124.6 million pounds of scrap material downgraded or exported in 197b contained potentially recoverable critical strategic elements. The amount of scrap material lost to the six alloy-producing industries in this manner contained 22.1 million pounds of chromium, 53.4 million pounds of nickel, 5.9 million pounds of cobalt, 35.9 million pounds of iron, and 7.3 million pounds of other alloying elements.

Jan 1, 1980

By W. N. Marchant

[The citrate process for flue gas desulfurization (FGD) is a product of continuing research by the U.S. Bureau of Mines to meet the goal of minimizing the objectionable effects of minerals industry operations upon the environment. The reduction of SO2, in solution by H2S to produce elemental sulfur by the citrate process is extremely complex and results in solutions that contain at least nine different sulfur species. Process solution analysis is essential to a clear understanding of process chemistry and its safe, efficient operation. The various, chemical species, the approximate ranges of their concentrations in citrate process solutions, and the analytical methods evolved to determine them are hydrogen sulfide (~0M to 0.06M) by specific ion electrode, polysulfides (unknown) by ultraviolet (UV) spectrophotometry, elemental sulfur (~0M to -0.001M dissolved, ~0M to ~0.1M suspended) by W spectrophotometry, thiosulfatc (~0M to ~0.25M) by iodometry or high performance liquid chromatography (HPLC), polythionates (~0M to ~0.01M) by thin layer chrornatogrphy (TLC), dithionite (searched for but~ not detected in process solutions) by polarography or TLC, bisulfite (~0M to 0.2M) by iodometry, sulfate (~0M to 1M) by a Bureau-developed gravimetric procedure, citric acid (-GM to 0.5M) by titration or visible colorimetry, glycolic acid (~0M to 1N) by HPLC, sodium (~1.5M) by flame photo¬metry, and chloride by argentometric titration.]

Jan 1, 1980

By R. L. Loofbourow

Most wet mines face unquantified water costs as well as the obvious wing costs. Both kinds of cost are multiplied by work at greater depth and by higher unit prices. This intensified challenge merits renewed or perhaps altogether new response. Any practicable way to reduce inflow tackles both obvious and unquantified costs. Ten groups of possible ways to do it are cited. Most have been demonstrated. Two are known from work other than mining. Surely new means can be found. Here are opportunities for operators of wet mines!

Jan 1, 1980

By A C. Carter

The increasing need for alternative energy sources as well as the less clearly perceived but equally increasing demand for non-fuel minerals has resulted in extensive exploitation of near surface deposits. Many such deposits have depleted reserves and mining corporations are increasingly turning their attention to deposits, with thicker overburden, less competent materials, steeper dips and more complex structure. These deposits pose mine layout, geotechnical and equipment problems as well as the need for large outputs to achieve economies of scale. The paper describes the major problems and operational solutions for such deposits using continuous excavation and transport equipment.

Jan 1, 1980

By Dale W. Norris

United States Steel's Cumberland Coal Operations is located in Greene County in the southwest corner of Pennsylvania. The mine and related facilities have been in operation since September of 1977. Production from this mine, U. S. Steel's first commercial coal mining venture, will eventually reach a level of 2.72 million mt of clean coal per year and is totally committed to electric power generation. Cumberland is a slope mine in the Pittsburgh seam and is mined by continuous mining machines and longwall. The coal from the mine is trans- ported by belt to the surface, taken through a rotary breaker for initial preparation, and stored in raw coal silos. It is then processed through the preparation plant and taken to a clean coal silo where it is held for train loading. Cumberland Mine operates its am 28.16 km railroad to transport the coal to the Monongahela River. The unit train consists of thirty-one 90 mt cars. The coal, once loaded on barges, is then shipped to the customer. Cumberland Mine is one of the most modern coal preparation and unit train loading systems in the nation. The preparation plant is de- signed to receive coal from the silos at a rate of 720 at per hour. The +6.35 mm material is screened out and cleaned in a Daniels heavy media vessel with two 3.35 m weirs. Minus 6.35 mm material is fed to sixteen #88 Deister concentrating tables. The cleaned coal from this circuit is dewatered, and all effluents from the mechanical dewatering report to the classifying Cyclone sump for classification through ten 35.6 cm cyclones. The cyclones overflow material (-150 mesh) is processed through two banks of three 8.5 m3 Denver D.R. flotation machines. The cyclone underflow pro- duct (28-1 0 mesh) is processed in two banks of 5 six 2.83 m Denver Sub A machines. The clean flotation product is then dewatered in Bird screen bowl centrifuges, blended with the other clean coal size fractions, and the total plant product further dewatered in a thermal dryer.

Jan 1, 1980

By William H. Holley

Thirteen additional preservative/fire retardant systems were applied to Ponderosa pine and evaluated for flammability both before and after water leaching. The more promising four systems were given a thorough evaluation for flame spread, toxic gas and smoke density levels, resistance to decay, and compressive strength. The most promising system on the basis of history of usage in the mine, ease of application and low cost as well as overall performance is the Fyreprufe/ACC Albi 107A/ 144 combination. A survey of inspection tools and instruments, identified equipment which could be assembled into an inspection kit for use in determining the extent of decay and/ or impregnant retention levels in mine timber. A literature search identified those high fire hazard areas found in a typical mine. Timber and other wooden structures used in such areas should be treated with an acceptable fire retardant system. A survey of insurance companies revealed that the use of such treated timber in the mines would probably have little or no impact on the rate structure.

Jan 1, 1980

By K. Ananthanarayanan, R. I. L. Guthrie, S. A. Argyropoulos

"The low cost and availability of micro-computers and their peripherals provides the metallurgical engineer with the opportunity to use such computers in a wide variety of applications. In this paper, the authors describe the development of a low cost data acquisition system capable of measuring up to 8 analogue channels at a sampling rate of up to 5000 measure mentsper second. This system is equipped with proper hardware and software so that the micro-computer can be linked to a central computer facility such as the McGill System for Interactive Computing (MUSIC). This central computer facility is supported by an AMDAHL V7 computer. Using the present interface, communication rates between the microcomputer and the central computing facility can be as high as 9600 (baud).The above mentioned data acquisition system is currently used for monitoring dissolution kinetics of ferro-alloy additions in liquid steel. In addition to this, special software has been developed which enables the user of this system to monitor solidification rates of ingots, etc. As economic considerations are always important, comparisons have been made with existing recorders which show that the cost Of the present system is only 30 per cent more than a two-pen strip chart recorder.RESUMELa disponibilité et le bas prix des micro-ordinateurs et de leurs périphériques permet à l'ingénieur métallurgiste d'utiliser de tels ordinateurs pour diverses applications. Dans ce rapport, les auteurs décrivent le développement d'un système d bas prix pour l'acquisition des données, capable de mesurer jusqu'à huit canaux analogues jusqu’à une vitesse de 5000 mesures par seconde. Ce système est équipe avec son propre ""hardware"" et ""Software"" qui relient le micro-ordinateur d’un ordinateur central, comme le système de McGill pour computations réciproques (MUSIC). Ce central d'ordinateurs est soutenu par l'ordinateur AMDAHL V7. Utilisant cet "" interface"", la vitesse de communication entre Ie micro-ordinateur et l'ordinateur central peut atteindre jusqu'd 9600 (baud)."

Jan 1, 1980

By D. W. Dareing

Multiple branch wellbores and horizontal holes, when applied to deep lying ore bodies, have the potential of significantly reducing well costs by reducing total footage drilled per acre of well pattern. In addition, horizontal holes may increase sweep efficiency. Well completion is a major problem. They must be cased to contain leaching solutions within the underground portion of the production loop. Several drilling and completion concepts are given and evaluated in the report. Our evaluation shows that there is economic incentive to further develop these concepts for field application to ore bodies 1,500 feet. Multiple branch concepts are the most attractive. They can reduce well costs by as much as 30° when applied to 2,000 feet ore body depths (44%, at 5,000 feet) and can accommodate a lamer pump than conventional vertical wells. We recommend this concept be developed further to accommodate either dual or triple branches.

Jan 1, 1980

By Charlie Wyche

The British Solomon Islands Protectorate continued developmental work on bauxite deposits on the Islands of Rennell and Vaghena. A feasibility study was completed by Mitsui Mining & Smelting Co., Ltd., and Pacific Aluminum Ltd. (a subsidiary of Conzinc Riotinto of Australia Ltd,), and negotiations with the Government were in progress. The Government will receive a 25% share if the project is realized. It was estimated that the Islands contain 60 million tons of bauxite with an alumina content of 45% to 50%.

Jan 1, 1980

By S. J. Lefond

Most people, when Borates are mentioned, mentally visualize the famous twenty mule team (really eighteen mules and two horses), trudging across the Mojave Desert or "she burns green Rosie, we are rich." Actually, however, the first use of borax was prior to Babylonian times. Their emissaries had orders to bring borax Iron the Gobi desert for use as a flux by the Babylonian goldsmiths. The borate mineral imported for this is not known but probably was borax. The ancient Persians and Arabians knew about borax and the Arabic word "Baurach" appears in a two thousand year old manuscript. The Sanscrit word for borax was tincana which has been corrupted to tincal. The Chinese were using borax as a glaze in three-hundred B.C. Marco Polo brought the first borax, along with gunpowder and spaghetti, from Mongolia to Europe in the late 1300's. Borax from Tibet was imported to Europe for nearly 500 years. In 1772 boric acid (sassolite) was discovered around Tuscany, Italy as a precipitant from volcanic steam vents. Production of boric acid started there about 1815 and provided the sole competition to the borax from Tibet. Borate deposits in Turkey have been known and exploited on a small scale since the 13th century. It is only recently that the operations are being modernized and production increased. About 1836, borax minerals were found in Chile and Argentina with borax production starting in 1852 in Chile and in Argentina in 1886. During the latter half of the 19th Century, Chile was the principle world producer of borax.

Jan 1, 1980

By G. M. Ritcey, K. E. Haque, S. H. Lucas

"Laboratory-scale hydrochloric acid leach tests were conducted on an Elliot Lake uranium ore. Hydrochloric acid leaches without an oxidant or with molecular oxygen (i.e., air or pure oxygen gas) as an oxidant favoured uranium and radium extractions. Conditions for maximum uranium, thorium and radium extractions with hydrochloric acid in the presence of sodium chlorate were determined. The highest extractions of uranium (96%), thorium (81%) and radium (91%) were obtained using a mixture of 44.0 kg HCI and 2.5 kg NaCIOJ per tonne of ore at 75°C with 18 hours ' retention.Flowsheets for two-stage leaching are proposed. The residues obtained from the second-stage leach contain uranium (0.002%), thorium (0.006%) and radium (15 to 20 pCi/g). Tailings of this nature are considered suitable for mine backfill, and, if pyrite is removed, suitable for surface disposal.IntroductionThe nuclear energy industry forecasts an increasing demand for uranium. This increasing demand requires not only largescale mining and processing of conventional and complex uranium ores, but also leads to the consideration of new and nonconventional sources of uranium, e.g., black shales, phosphate rocks, granite, sea water and fossil-fuel ash."

Jan 1, 1980

This publication summarizes the in-house and contract research and development projects programed for fiscal pear 1980 by the Bureau of Mines under its Minerals Environmental Research activity. The document provides a mechanism for interested parties, including potential contractors, to gain insight into ongoing and projected work of the Bureau's environmental research efforts. Research to identify and correct environmental problems associated with mining and metallurgical operations has long been an integral part of the Bureau's mission. Through the years, efforts of various Bureau programs have yielded valuable information on the origin and control of many of these problems. With the reorganization of the Bureau of Mines in 1979, the Minerals Environmental Technology program was structured to consolidate these efforts into a single program that will systematically investigate al aspects of mining- and processing-related environmental pollution and damage-from initial discovery of the mineral resource to ultimate return of the land to productive use. In fiscal year 1980, the Bureau received an appropriation of about $21 million to conduct research and development work on these problems.

Jan 1, 1980

By J. A. Eisele

The Bureau of Mines conducted bench-scale cyclic tests to determine the composition of recycled leach liquor in the Bureau?s proposed clay/HCl leach/ HCl sparge process for producing Al203 from clay. The data developed from these tests make it possible to synthesize leach liquors for predetermined steady-state operating conditions when conducting large-scale crystallization tests. The results of two sparge tests were compared. One was a 20-cycle test with a 36-pct-HCl concentration in the mother liquor; the other was a 10-cycle test with a 26-pct-HCl concentration in the mother liquor. The effect of impurity concentrations in the leach liquor on the purity of aluminum chloride (AlCl30?6H20) crystals was determined, but there was poor correlation between this data and results that have been obtained from miniplant-scale work.

Jan 1, 1980

By L Torckler, R L. Brathwaite

At Neavesville gold-silver (electrum) mineralisation occurs in steeply-dipping zones of intense fracturing, brecciation and quartz veining within rhyolitic pyroclastics, carbohaceous shales and andesites. Hydrothermal alteration extends over an area of greater than 3 by 1.5 km. In rhyolitic tuffs, highly silicified zones containing quartz-adularia-illite assemblages are flanked by less silicified assemblages composed of albite, illite-montmorillonite and chlorite. The mineralogy and sequence of alteration are comparable with the alteration zones which envelop the steam-producing fissures of the active Wairakei and Broadlands geothermal fields. Primary fluid inclusions in quartz from five fissure veins in the Neavesville field show maximum homogenisation temperatures ranging from 220 - 260¦C and salinities of 0.0 - 1.1 wt per cent NaCl equivalent, which cover a similar range to actual measured temperatures and salinities in geothermal fluids at Wairakei and Broadlands. The age of the rhyolitic pyroclastics and related alteration and mineralisation is probably Pliocene and Neavesville therefore represents a fossil geothermal system. The intensely fractured zones containing the gold-silver mineralisation were probably produced by hydraulic fracturing generated by accumulation under pressure of hydrothermal fluid in blind fault zones. Study of fluid inclusions indicates that hydrothermal quartz associated with electrum was deposited under boiling conditions. High grade electrum mineralisation at Graces workings appears to be localised by reaction of hydrothermal fluid with sedimentary marcasite in black shale.

Jan 1, 1980

By J. D. Nye, I. A. Farr, W. J. D. Stone

"A unique deposit of barite exists near Brookfield, Nova Scotia. The crystals are extremely fine and the whole deposit virtually free of heavy metals. The deposit size was not large enough for conventional uses, such as the production of barium carbonate and drilling mud. In an effort to obtain maximum utilization, a program was begun to determine if U.S.P.-grade pharmaceutical barium sulphate for X-ray diagnosis could be produced. Early work was sufficiently encouraging to institute a development program under the federal Program for Advancement of Industrial Technology. This has been very successfully completed. Canadian and U.S. process patents have been issued, clinical trials have been successful, a production plant has been designed and the plant’s production sold. The processing plant will include magnetic separation for the removal of iron minerals, fine grinding by paddle milling to minus one micron and acid leaching. The process is unique in that at no time is the barium taken into solution.Information is given on the deposit, process, markets, use, plant capital and operating costs, and projected profits. The initial production plant will have an annual capacity of 2,000 tons per year of end product. Capital cost is $850,000 and annual turnover more than $1.5 million. As this capacity only represents approximately 15% of the North American market, rapid plant expansion is foreseen."

Jan 1, 1980

By T. A. Raczek

Materials for stronger ventilation tubing for underground use in hardrock mines were developed. The new material composites were evaluated in performance characteristics and compared to currently used materials. The materials were compared on tear, tensile, puncture and flammability properties. Based on cost versus performance data, a polyester film bonded to a polyester fabric was selected as the candidate material for field testing. Ventilation tubing fabricated from the selected material was field tested in two underground uranium mines for four-month periods. The test results indicated that the new composite showed an increase in useful life in the majority of applications, However, the cost performance ratio was not significantly improved to warrant commercialization of the product. When connected directly to some blowers, the material in close proximity to the blower deteriorated. However, material which was punctured or torn by mechanical means did not have further propagation of the tear. The high tear strength of the material prevented further damage. Improved methods of repairing inflated ventilation tubing were investigated and developed. All the repair methods were portable and self-contained. Repair kits based on adhesives, pressure sensitive tapes, and mechanical means were evaluated. Plier staplers and patch systems based on pressure sensitive adhesive proved to be most functional.

Jan 1, 1980

By Peter P. Kopas

Study, analysis, fabrication and testing for canopies on Roof Bolters and Shuttle Cars in coal seams under 48?.

Jan 1, 1980

By Mark S. Stagg

Blast-induced ground vibrations from surface coal mine, quarry, and construction blasting were measured and analyzed for frequency content and duration characteristics. Eighteen commercially available ground vibration measurement systems were evaluated in the field and laboratory for linearity, accuracy, and crosstalk. Buried, surface, and sandbagged transducer placement methods were compared, along with peak and vector-sum measurements. The recommended minimum frequency ranges for ground vibration instrumentation are 2 to 150 Hz for coal mine and quarry blasting, and 5 to 200 Hz for construction and excavation blasting. When higher or lower frequency vibrations are possible, as in construction blasting or for a quarry shot close to a residence, care should be taken to insure proper choices of instrumentation and vibration criteria. Several instruments operating in these ranges are available, and all but one of the seismographs tested fell within ±3-dB accuracy limits (+41 pct, -29 pct). Waveform recordings of all three ground vibration components are recommended as the peak amplitude and frequency may vary among the three. Peak or vector-sum readings are adequate if only amplitude levels are desired. The soil density matched box should be anchored or buried, particularly for high-frequency, high-amplitude construction blasting.

Jan 1, 1980

By Steven A. Hawkins

This report details the conduct and results of a 5-month study to collect data on the use of steel support for ground control in European underground coal mines. The report summarizes European steel support design practices and describes the applicability of steel supports to U.S. mining conditions.

Jan 1, 1980

By David D. Rabb

A report on location, sampling, assays, mineral examination, amenability leach tests, and evaluation of certain mine dumps in Mohave County, Arizona. Extractions of greater than 30 percent of the gold and silver were achieved during simulated heap leaching of selected mine dump material. Consumption of reagents was relatively low and results suggest leaching of prepared heaps is technically viable and could be economically attractive.

Jan 1, 1980