Search Documents

THE object that the writer has mainly in view in presenting this paper is to draw the attention of those connected with the technical side of the industry to the unsatisfactory and by no means up-to-date methods employed in estimating the tin contents of an ore. At the same time, what is regarded, from the writer's personal experience, as a satisfactory and reliable method is explained in detail. It is a curious fact that for the last 25 years tin·assay methods have made little or no advance, while those now in general use ill connection with copper and lead ores can scarcely be compared with those then obtaining, so greatly have they been improved upon. Though it. is not altogether expected that the method herein advocated will at once meet with general approval, the writer hopes the resultant discussion may bring out points that have hitherto escaped detection.FIRE METHODSThe old Cornish method of smelting with anthracite is now obsolete. The cyanide assay, although unreliable, is still much used because of its simplicity. In the Malaya many buyers of tin ores use the cyanide assay, the smelting being carried out generally in a benzine furnace. It is essential that the smelting with cyanide be performed at a low temperature. Even then, impurities, such as Sb2S3 and...

Jan 1, 1912

By Paul M. Tyler

Magnesite is of importance primarily as a refractory material for lining steel furnaces , although substantial amounts are used in the production of flooring compositions and other building materials and for certain chemicals , notably epsom salts . Since consumption for all of these purposes is largely in the eastern United States and domestic deposits are situated in California and Washington , this country's magnesite mining industry , which was created largely by war- time conditions , has subsequently been sustained by tariff protection .

May 1, 1931

By Ronald T. Mayerle

In 1989, the U.S. Bureau of Mines conducted a mineral investigation of the Mallard study area near Elk City, Idaho. The study area comprises most of the original Mallard RARE II area (1-847) plus some additional lands. The investigation is part of an ongoing, multi-year study of north-central Idaho that is being conducted in cooperation with the Idaho Geological Survey and the U.S. Geological Survey (USGS). The only identified resources are rock suitable for road metal. Five lode prospects and a pyrite-bearing rock quarry, which is operated by the Forest Service for aggregate, were examined for metals. One of the prospects warrants additional exploration for silver in quartz veins, but the chance of finding an economically minable deposit is limited. Several rock and stream sediment samples were anomalous in various metals. Two of the more promising localities for gold and/or other metals are adjacent to a unit of the Frank Church-River of No Return Wilderness that the USGS classified as having a moderate potential for gold deposits related to fossil hot springs.

Jan 1, 1991

The passage of chloroform vapour in a carrier of oxygen through two nickel sulphide ores heated to 380°C converted the nickel to the water soluble chloride form. In one ore the nickel (2·75 per cent) was presentas violarite ((Ni, Fe)3S4) whereas in the second it was present as pentlandite, ((Fe, Ni)9S8) (4·9 per cent Ni).A similar technique was utilized to convert nickel in nickeliferous laterites (1·6 per cent Ni) into a soluble chloride using town gas instead of oxygen as a carrier.With both techniques greater than 90 per cent extraction was achieved.

Jan 1, 1972

By L. C. IlsLey

[In 1922 a conference of representative coal-mine operators, cable manufacturers, mining-machine manufacturers, and representatives of the United States Bur eau of Mines vas held at the Pittsburgh Experiment Station, regarding suitable cables for use with permissible raining machines. This conference recommended that the Bureau investigate rubber-sheathed trailing cables in order to obtain specifications for tests leading to approval for rise with mining machines. Effective until such time as an investigation could be made, the bureau asked the several manufacturers of approved mining machines to recommend cables for wise with their machines. In general the Cables recommended tentatively approved. Arrangements for the tests were completed in 1927. Concentric-type cables were investigated first, and Reports of Investigations, Serial No. 2909, covering the tests, was issued in January, 1929.]

Jan 1, 1929

By Glan Dale Coe, Will H. Coghill

"INTRODUCTION Characteristics of the mineral products that are to be contrasted herein are net energy consumed in grinding to a definite top limiting size and size distribution of the ground products. Through contrasts of these grinding characteristics this paper to differences in related mineral products and in unlike products. For,example, in anticipation of the data to follow, although Joplin chert and Babeitt taconits are running mates in defying the best crushing machinery, taconite is one of the more docile and Joplin chert one of the most refractory mineral products ordinarily fed to a grinding Routine grinding tests on a great variety of ores and tabulation of the findings have been covered amply by Lennox 4/ and by Maxon 5/ and associates. In contrast to that work, the present paper is a record of random tests made over a long period, and each answered an urgent question at the moment. The work was done at the Southern Experiment Station of the Bureau of Mines, United States Department of the Interior, in cooperation with the University of Alabama. The pressure of war work prevented an organized investigation."

Apr 1, 1943

By M. F. Lopez, A. J. Mattus, S. B. Magid, D. B. Mobbs

"The use of Caro's acid as a replacement for hydrogen peroxide for the oxidation of vanadium prior to solvent extraction resulted in a 56% reduction in oxidant usage when compared on an equivalent hydrogen peroxide basis. Comparative oxidation tests, using two actual uranium mill raffinates, resulted in premature precipitation of an amorphous ferric vanadate when hydrogen peroxide was used to oxidize one of the raffinates containing a high iron to vanadium ratio. The use of Caro's acid eliminated the precipitation problem, thereby permitting the adjustment of the raffinate pH to a higher, more favourable level prior to solvent extraction.Potentiometric characterization of the raffinates revealed that vanadium is responsible for the inefficiency of hydrogen peroxide compared with Caro's acid, with the oxidation efficiency of iron being the same for both oxidants. A limiting potential between 720 and 740 mV was observed when using hydrogen peroxide, while, when using Care's acid, potentials approaching 1200 mV were achievable.A four-stage, countercurrent extraction performed on the oxidized raffinates did not reveal any operational problems. The extraction efficiency and the extraction coefficient were found to be higher when Caro's acid was used as the oxidant, as opposed to hydrogen peroxide.IntroductionMost vanadium is recovered as a by-product of some other process: leaching of Carnotite uranium ores, oil fly ash, phosphate rock or chromite processing. The major source of vanadium has been from uranium mills incorporating acid leaching of Carnotite ore s at elevated temperatures and pressures. The by-product recovery of vanadium from uranium ores of the Uravan Mineral Belt, located in the Colorado Plateau , is a common occurrence when vanadium recovery is economically viable."

Jan 1, 1983

By S. K. Sahoo, S. K. Sharma, U. K. Singh, G. S. P. Singh

This research focuses on the strata control issues in a Bord and Pillar depillaring working under the influence of dead load condition of voluminous and fragmented softcover of overburden dump material. It reports the modeling of a mine working through the FLAC 2D software under the Indian geo-mining conditions. The modeling results of an actual mine working under softcover were compared with that under the intact overburden condition to assess the influence of the soft overburden over the depillaring working. The modeling work involved progressive caving of the strata and the cyclic goaf filling following the modelsimulated occurrence of main fall and periodic caving. Mohr-Coulomb Failure criteria along with a simplified strain-softening (MCSS) model was used to study the failure and caving mechanism. Salamon’s compaction model was used to simulate compaction and resultant stress recovery in the goaf material. Comparison of the model findings was done in terms of load on supports, abutment stress, and convergence, apart from the stress redistribution and failure mechanism. The load transfer mechanism of the soft overburden was also studied for an overall understanding of the strata behavior in such workings.

Jun 16, 2020

By N. E. Rogen, N. J. Grant

WHILE direct measurements of the growth of precipitate particles during aging is of fundamental value, few such measurements have been made. Direct measurements by means of optical or electron-microscopy and X-ray techniques are preferred, however, many of the aging studies have been based on indirect methods such as electrical resistivity and hardness. Because of the minute size of most precipitate particles (less than 1000A) the light microscope is of limited use while electron microscopy is subject to slowness, etching problems and consequent resolution problems. It is fortunate that alloys of the Nimonic type, based on Ni-Cr-Ti-Al, lend themselves to accurate and relatively easy particle size measurements. With proper balance of titanium and aluminum, the only aging precipitate is the gamma prime (r') Ni3,(Al, Ti)2 phase and this phase is the basis of the high-temperature strength of these allos.3-6 The Ni3(Al, Ti) phase is a face-centered-cubic, ordered structure with nickel atoms occupying the cube faces. Titanium atoms can replace three out of every five aluminum atoms and when substituting do so preferentially.2 Electron microscopy has shown that during aging of most of the commercial alloys of this type, precipitate particles are unusually uniform in size and distribution, and that the volume of (r') phase is large (20 pct).4,7 The aim of this investigation was to measure the growth of (y') phase during aging. In so doing, it was hoped that a clearer understanding of the aging process would be attained. X-ray line broadening was used as the measure of precipitate particle size. This technique was selected because it can measure and average the diameter of thousands of particles in one operation. The variations in hardness and matrix lattice parameter with aging were also studied and related to the particle size. EXPERIMENTAL PROCEDURE An alloy of the following composition was studied: Cr Ti A1 C Ni Wt pct 20.71 2.98 1.43 0.04 bal. At. pct 22.06 3.47 2.95 0.18 bal. The alloy, a 15- lb vacuum melt, was forged to 1/2-in. diam at a temperature of 1900" to 2200°F; was solution heat treated for 4 hr at 2000°F and water quenched; and was then aged in various ways. The ASTM grain size was 4 to 5. No (7') phase could be detected by X-ray analysis after solution treatment and electrolytic extraction. Aging was performed on 2-in. long specimens at 1400°, 1500°, and 1600°F for increasing times. One-half inch sections were removed after each time increment and were then electropolished in a solution of H3P04 saturated with chromium trioxide at a potential of 30 v and rectified with a tantalum electrode. Rockwell hardness measurements were taken using one side of the polished specimen. Matrix lattice parameter determinations were made on the other side using filtered chromium radiation references with the position of the (220) line of a silicon standard. To enable the precipitate particles of the (y') phase to be measured using X-ray line broadening techniques, it is first necessary to separate and concentrate this phase by electrolytic extraction. Extraction is necessary because the difference between matrix and precipitate lattice parameters is only approximately 0.5 pct and intensities of.the (y') phase lines are very weak relative to those of the matrix. The extraction techniques employed have been described before and found to produce a reasonably quantitative separation.398 A water solution of 15 pct H3Po4 is used at a current density of 0.5 amp per sq in. at 6 v. The precipitate particles are separated from the liquor by centrifuging and decanting and are then washed, dried and repowdered. A plot of the X-ray intensity vs diffraction angle for the (111) line of the precipitate particles was used as a measure of particle size. The intensity curve approximated the shape of Gaussian distribution function and its breadth was measured at the half height. The (220) line of a silicon standard was used to correct the measured line breadth for instrumental and other broadening errors. The Scherrer formula was used to calculate particle

Jan 1, 1961

The content of the book covers: (1) The theory of the Eötvös torsion balance; derivation of the working formulas; description of the instrument; method of observation; relation of the magnitudes observed to the lines of force and the level surfaces of gravity; corrections or normal effects, near and distance terrane; subterranean effects; effects due to certain mathematical bodies. (2) Notes on the practical employment of the Eötvös torsion balance; initial testing of the instrument and of accessories; hints on planning the survey; work at the station site; office computation and plotting of results; the interpretation of the results: (3) A description of the instrument and instructions for its manipulation. This book was the best discussion in English on the theory and use of the Eötvös torsion balance and is surpassed only by a later paper by the same authors that covers much of the same ground. The book is suitable for a textbook for beginners, and advanced students will find it of use. It should be available as a reference book in all geological libraries and in all torsion balance department offices.

Jan 1, 1929

By Pamela J. Watson

This report presents a Bureau of Mines literature survey that provides a data base useful for current and future studies in the area of chemically enhanced drilling and cutting. Publications describing laboratory testing and field studies of drilling and cutting with chemical additives are reviewed. Significant results are summarized and tabulated by rock or material type and also by chemical additive, with extensive references. Selected studies related to fluid-enhanced processing or material testing are summarized in the appendixes.

Jan 1, 1985

By Ewan Wingate, Ranjit Prasad, Yanjun Liu

The use of phosphorus by mankind is long established. From use in agriculture, foods, high tech electronics, and more recently in EV battery cathode production, one cannot escape its impact on today’s society. This paper will review and describe the circular journey of phosphorus through its value chain from the mining operation of phosphate ore through beneficiation into downstream chemicals production and finally into the EV battery cathode production space. This will include a review of phosphoric acid production from phosphate concentrate using wet process route and thermal route. The wet process route discussed will be via dissolution of phosphate concentrate by sulphuric acid. The thermal route will discuss thermal decomposition of phosphate concentrate using submerged arc furnace to produce yellow phosphorus followed by its combustion to produce phosphorus pentoxide and subsequent hydration to produce phosphoric acid. It will also discuss briefly other phosphate derivatives for specialty chemicals and recovery of phosphorus units from wastewater treatment plants, sewage sludge and incinerator ash. Finally, the paper will discuss the use of phosphorus in EV batteries in the form LFP cathode materials and its production. It will also briefly discuss the LFP battery recycle.

Sep 11, 2023

The first metal-mine accident-prevention course was prepared and published in 1942-45 as a series of seven miners' circulars (Nos. 51-57). The course has been broadened in scope, revised, and brought up to date and is being published as a similar series of seven miners' circulars (Nos. 51-57, revised) on accident prevention in metal and non-metallic mines. These circulars are as follows: Injury Statistics (Miners' Circular 51), dealing with general statistics on injuries from accidents at metal and nonmetallic mines, including causes, costs, and the use of investigations and reports of all injuries.

Jan 1, 1960

By Wenjun Ju, Xiaodong Sun, Jianwei Zheng, Bingding Yi, Zhaorui Ma, Pengfei Jiang, Lingfu Zhu, Yangfa Zheng

The presence of hard roof poses a significant threat to the safety of underground coal mining. In this study, a mechanical model is established for underground stopes to analyze the overburden structure with the advancing of the mining face. It is indicated that the load-bearing arch structure (LBAS) is formed above the stope for roofs with regular hardness, whereas the reversed-basin bearing structure (RBBS) is formed for hard roofs. Compared with the LBAS, the RBBS can induce an additional pressure at the foot of the bearing structure, and this effect becomes less as the distance between the hard roof and stope increases. The ultra-deep borehole hydro-fracturing technique (UHT) is proposed to weaken the hard roof for pressure release, and the associated equipment and procedures are also presented. The UHT is based on horizontal drilling along the axial direction of the roadway in the roof, and then the receding segmented hydraulic fracturing technique is used to achieve the purpose of fracturing (weakening) of the surrounding rocks. Field tests are carried out in 3022 roadway of Daliangwan coal mine in Yulin to assess the developed technique, equipment, and fracturing procedures. To evaluate the fracturing effect, deep borehole stress-meters are installed at different depths of the fractured and un-fractured zones of the roadway, along with hydraulic support pressure sensors placed at the mining face. The results show that compared with the un-fractured zone, the pressure on the wall and pillar sides is lower than that in the fractured zone, and the associated weighting duration and weighting area ratio of the fractured are reduced by 53.23% and 33.59%, respectively. This indicates that the presented UHT can provide a new solution for the prevention and control of mining disasters induced by hard roof failures in underground coal mining.

Nov 2, 2020

By John Nagy

Dust explosion data obtained in laboratory tests by the Bureau of Mines are presented for 181 miscellaneous materials that present an explosion hazard. Data are given also for 50 dusts that present primarily a fire hazard and for 88 dusts that did not present an explosion hazard.

Jan 1, 1968

By Gordon Bath

During the summer of 1946, the Division of Geophysical Exploration of the U.S. Bureau of Mines established several primary magnetic base stations near important iron-producing districts in Minnesota, Michigan, and Wisconsin. Stations were located in groups of four to six in six separate base-station areas, and each position was marked with a concrete monument. Differences in magnetic intensity between stations in these areas, as well as the difference between each area and a magnetic datum at the magnetic observatory of the Coast and Geologic Survey at Cheltenham, Md., were measured with a modified Askania magnetometer. Measurements also were made with a Hotchkiss superdip to study the usefulness of the stations for the calibration of instruments of this type. The work was planned and supervised by F. W. Lee, chief of the Division of Geophysical Exploration, and Edward F. Fitzhugh, Jr., chief of the Minneapolis Division of the Bureau of Mines. Special mention is due Harold B. Ewoldt, Bureau of Mines engineer, for his assistance in the field work, especially in locating and establishing monuments. Special mention also is due Clyde L. Holmberg, of the Bureau of Mines, for the magnetic measurements made with the Hotchkiss superdip. Helpful suggestions were received in the field from H. L. James, of the U. S. Geological Survey. Acknowledgment is made of the cooperation of Stephen Royce, Irving E. Beckwith, Arthur Johnson, and Josiah Royce of Pickands, Mather & Co., and A. E. Matson, of Butler Bros. The U. S. Coast and Geodetic Survey furnished daily magnetograms from the Cheltenham Magnetic Observatory as well as calibration equipment and values of absolute magnetic intensity. Short-term forecasts of ionospheric conditions were obtained from the National Bureau of Standards.

Jan 1, 1951

By Nadia C. Miller

In situ metals research to characterize the hydrology of a fractured crystalline rock mass in under-ground mine stopes is discussed. The objective of this study was to find the potential direction, velocity, and concentrations of a lixiviant plume, should leaching solvents (lixiviants) escape from a test stope. The study was conducted by the U.S. Bureau of Mines at the Colorado School of Mines Experimental Mine in Idaho Springs, CO. Since this was a method evaluation site, the lixiviant was simulated using water and acceptable tracers. The site is located in moderately fractured Precambrian migmatite-biotite gneisses of the Idaho Springs Formation. The data required for the characterization were obtained from geologic maps and reports, core logs, and air and water permeability tests. The acquired data were analyzed and applied to a computer model that calculated' the characteristics of a lixiviant plume originating at the stope. A sensitivity analysis showed that dispersivity, ground water velocity, fracture porosity, and fracture spacing had notable effects on the concentration of the plume. Assuming a saturated rock mass, the lixiviant plume would disperse to undetectable levels in a very short time because of a high fracture density at the mine site.

Jan 1, 2010

By Claudio Rocha Rosales

"Peñoles is a mining group with integrated operations for the smelting and refining of non-ferrous metals, and it is also a chemicals producer. Peñoles is the world’s foremost producer of refined silver, metallic bismuth and sodium sulphate. It is also the leading Latin American producer of refined gold, lead and zinc. The Met-Mex Peñoles Zinc Plant commenced operations in 1973 with an annual production capacity of 105,000 t/y zinc. Since then, production capacity has increased, and at present, it stands at 240,000 t/y zinc. In this paper, the leaching process and particularly the operation of the jarosite circuit is reviewed, specifying process improvements to treat high iron calcines.INTRODUCTIONTwenty years ago the Electrolytic Zinc Plant in Peñoles was treating high quality zinc concentrates with low concentrations of iron (~7.5 wt.%) and silica (1.8 wt.%). Nowadays the quality of zinc concentrates is poor with a typical iron content of around 11 wt.% and silica at 2.0 wt.%. This has created numerous processing problems in our roast-leach-purification- electrolysis sections. In order to meet customer requirements it is necessary to find processing solutions to assure the operational continuity of the plant. These processing solutions are the focal point of this paper.REVIEW OF THE LEACHING PROCESSThe purpose of the leaching process is to recover the metals, mainly zinc, through a series of extraction stages with sulphuric acid solutions, which progressively increases the zinc dissolution. After the series of acidification stages, the solution, which is rich in iron, is sent to the jarosite circuit to separate zinc from iron (Garcia & Valdez, 1996). The first step of the leaching process is the neutral leach circuit which produces a zinc sulphate solution that is sent to the purification section for the removal of impurities such as cadmium, cobalt and copper. Then this solution is sent to the tank house to feed the electrolytic cells."

Jan 1, 2016

By John E. Appleby

Grupo Acera, HYLSA originated in 1942 when Hojalata y Lamina began operations to supply steel strip for the Cuauhtémoc Brewery, the parent company. Production began in April, 1943 with growth accelerated because of World War II. By 1948 the company was producing its own steel from electric furnaces charged with scrap iron. Further expansion was hampered by the fluctuations in availability, price and quality of scrap iron. As a result, a search was made for a suitable process to enable HYLSA to satisfy its need for a reliable source of feed for its steel-making facilities. Their relatively low iron requirements at the time did not justify the very high capital investments required using the conventional blast furnace method. Processes which by-passed the blast furnaces were very much in their infancy and were not commercially tested. HYLSA then undertook an investigation of the direct reduction processes, knowing full well that much larger companies in other countries had investigated several processes but their work had not established a trend toward direct reduction or any particular process. However, after much effort and persistence HYLSA arrived at a process which suited their conditions. By using Mexican iron ore and natural gas they developed the now well-known H. y L. Process to produce sponge iron. Concurrent with the start of investigations which led to the H. y L. Process, HYLSA began an exploration program for a suitable source of iron ore. Thus in 1951, Cia. Minera Las Encinas, S.A. was formed, culminating in the development of the ore bodies near Pihuamo in the State of Jalisco. Mining commenced and ore was

Jan 1, 1971

By A M. Sherwood

The Otago and Southland lignite deposits represent by far the largest known fossil energy resources in New Zealand. Despite their size they have remained virtually untouched since exploration in the 1970s and 1980s defined their extent. In total there is an estimated 10.9 billion tonnes of lignite in 13 defined fields in Otago and Southland. Much of the exploration work only targeted seams at shallow depth and it is highly probable that there are further resources at depth in the fields that have been explored to date.   L&M Lignite Limited (L&M) holds exploration permits over a number of lignite deposits and is currently engaged in pre-feasibility studies to investigate the potential of the lignites for gasification. L&M is focussing its studies on the Hawkdun and Ashers-Waituna deposits. Coal quality in these deposits, particularly Ashers-Waituna, is highly suitable for gasification. In total the two deposits contain 1647 Mt of potentially recoverable lignite. L&M has engaged a variety of consultants to progress this project. The Hawkdun and Ashers-Waituna deposit databases have been re-evaluated and the resources remodelled. Further drilling has been carried out and the coal quality database has been expanded. The baseline project is to develop a mine to feed a plant that will produce liquids, specifically low-sulphur diesel and naptha, using the Fischer-Tropsch process. The project anticipates a staged development of 10 000 barrel per day units, each requiring mining at the rate of 12 700 tonnes of lignite per day. The production of other products including ammonia-urea, methanol, hydrogen and electric power is also under study.

Jan 1, 2005