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By H. Leitch

In laboratory experiments, the Bureau of Mines investigated melting, quenching, and sulfuric acid leaching of alumina from mixtures of albite and anorthite, and from anorthosites containing 26 to 32 percent alumina. Variations in pouring temperature, quenching and leaching conditions, were studied with respect to the extraction of alumina and impurities. Virtually all of the alumina was dissolved by leaching melted and quenched California anorthosite in boiling 16-percent sulfuric acid solutions for 15 to 30 minutes. The leach solutions were readily separable from the solid residue by conventional thickening and filtration techniques. Only 2 to 5 grams of SiO2, Fe2O3, or CaO dissolved per 100 grams of alumina. The quantity of SiOz in solution varied inversely with the duration of the leach and with the concentration of the H2SO4 solution used. Melted and quenched Wyoming and Minnesota anorthosites with SiO2:CaO weight ratios of 4.3 and 3.2, respectively, were less amenable to sulfuric acid leaching than California anorthosite with an SiO2:CaO weight ratio of 5.3. However, excellent results were obtained on the Wyoming and Minnesota anorthosites by the addition of SiO2 to these materials before melting, in quantities sufficient to adjust the SiO2:CaO weight ratios of the furnace charges to between 4 and 6.

Jan 1, 1966

By M. J. Ankeny

Coal-mine haulage ranks second as a cause of coal-mine fatalities, and the prevention of such accidents will materially improve progress in safety in the coal-mining industry. Beginning March 1950, Federal coal-mine inspectors were made responsible for completely investigating all fatal accidents in and around coal mines. During these 10 months, Federal coal-mine inspectors investigated 447 fatal accidents. This is a study of 121 of the fatal haulage accidents investigated, which constituted 27 percent of fatalities from all causes. Haulage employees represent only 12 to 15 percent of mine personnel, but, on the basis of accident frequency, their work is the most hazardous in coal mines. Fatal haulage accidents occurred in 53 bituminous coal-producing counties representing 14 States and Alaska. The physical conditions represent a cross section of' producing coal beds. Mining and transportation methods vary, from those of small hand-loading mines to those of modern mechanized mines.

Jan 1, 1951

By E. G. King

Difficulty has been encountered in making thermodynamic calculations of metallurgical reactions involving interoxidic compounds of the ferroalloy elements because of the serious lack of most thermodynamic data for these substances. This Bureau of Mines report (the first of a planned series dealing with entropies of vanadates, tungstates, and molybdates) presents low-temperature heat-capacity data and entropy values at 298.15° K. for three crystalline sodium vanadates--metavanadate (NaV03), orthovanadate (Na3VO4), and pyro-vanadate (Na4V2O7). The results are combined with data for the constituent oxides and elements to obtain entropies of formation of the vanadates. Previous to this report only one vanadate had been studied Similarly, ammonium metavanadate.4/

Jan 1, 1961

By K. K. Kelley, W. W. Weller

Heat capacity measurements of akermanite ( Ca,MgSiO ) , cordierite (Mg2A14 Sig018 ) , gehlenite ( Ca₂Al₂ SiO ) , and merwinite ( Ca ,MgSiO ) were conducted over the temperature range from 50 ° to 298.15 ° K. The entropies at 298.15 K ( expressed in cal / deg mole ) were evaluated as follows : Akermanite , 50.0 ± 0.5 ; cordierite , 97.3 ± 0.9 ; gehlenite , 47.4 ± 0.4 ; and merwinite , 60.5 ± 0.5 . All four compounds have positive entropies of formation from their constituent oxides at 298.15 ° K ; the values range from 4.6 cal /deg mole for akermanite to 10.1 cal / deg mole for cordierite .

Jan 1, 1963

By John W. Brown

Electrical resistivity surveys were conducted at three sites in Wyoming in an attempt to detect underground rubble zones in oil shale and to determine their size and resistivity contrast. The zones were detected at Rock Springs sites 4 and 5, but none were detected at Green River site 1. The resistivity of the rubble zones at sites 4 and 5 is greater than that of the surrounding rock. The zones at sites 4 and 5 are concluded to be roughly ovaloid in shape, with a horizontal diameter of 33 m and a vertical thickness of 24 m. Both rubble zones and the blasting that created them are considered to be centered at a depth of 24 m.

Jan 1, 1972

By C. H. Bloomster

This study estimated (1) radon and radon daughter emissions from underground uranium mines; (2) the reduction in radon that would be released to the surface by using control techniques such as bulkheads, sealants, backfilling, and positive pressure ventilation; (3) the cost for radon and radon daughter removal from total exhaust air; and (4) total radon and radon daughter discharge for lower occupational exposure limits. For 13 large underground uranium mines, estimated yearly radon emissions from each mine ranged from 900 to 3,400 Ci. The estimated age of air emitted from the mines ranged from 11 to 37 min. Potential radon removal methods for the total mine exhaust were evaluated. The cost of these methods was prohibitive. Diurnal and seasonal changes may affect radon emission over short periods of time, but do not affect the total emissions over the long run. Radon and radon daughter emissions would be little changed by increased ventilation requirements needed to achieve lower occupational exposure limits. The concentrations in the exhaust would be lower, but the total release would be the same

Jan 1, 1984

By Irving Hartmann

1. Under the conditions of the tests described herein, the proper use of an incombustible stemming plug of the type discussed prevented ignitions of gas in all tests during the firing of 21 single shots of permissible explosive in cool. In two tests with multiple blasting (four and five shots each) no ignitions resulted. 2. The results of a few tests in this investigation and of numerous tests made previously indicate that fire-clay stemming of the same weight as an incombustible plug provides about the same degree of protection as the plug against gas ignitions during blasting of coal by permissible explosives. 3. The hazard of gas ignition on firing charges of non-permissible 40-percent gelatin dynamite in coal was reduced but not eliminated when the shot holes were stemmed with one or two incombustible plugs or with an equivalent weight of fire clay. 4. On the basis of this investigation, the Bureau of Mines considers the proper use of incombustible stemming plugs of the design tested, under the conditions of the tests described in this paper, to be of equivalent safety as the same weight of fire-clay stemming. This report does not constitute approval or disapproval of the incombustible stemming plugs by the Bureau of Mines. 5. The test data indicate that misfired charges in shot holes stemmed with the incombustible stemming plug cannot be disposed of with certainty by the procedure recommended by the manufacturer. In this investigation the misfired charges failed to detonate in 30 percent of the trials.

Jan 1, 1950

By A. E. Isaacson

The U.S. Bureau of Mines determined the effect of common sulfide minerals on the corrosion rates of various types of ferrous alloy grinding media. Data obtained from this study will aid in determining the contribution of any electrochemical reactions between sulfide minerals and grinding media to the total grinding media consumption. Common sulfide minerals used in this study were chalcopyrite, galena, and sphalerite. In the presence of oxygen, chalcopyrite was found to increase the corrosion rate, galena was found to decrease the corrosion rate, and the effect of sphalerite was dependent upon the type of grinding media. Possible electrochemical reactions of these minerals in the presence of grinding media are suggested.

Jan 1, 1989

By A. E. Back

[Several processes for recovering manganese from low-grade ores have been proposed3/4/5/ in which an aqueous slurry of the ore is leached with gas containing nitrogen, oxygen, and sulfur dioxide as obtained from burning sulfur or roasting sulfide ores. The manganese dioxide is dissolved, and most of the sulfur dioxide is oxidized to sulfate, but an appreciable quantity of dithionate is usually formed, together with acid from oxidation of the sulfur dioxide. The over-all reactions may be represented as follows: (1) Mn02 + S02 = Mn++ + S04--. (2) Mn02 + 2S02 = Mn++ +S206--. (3) H20 + So2 + 1/2 02 = 2H+ 5S4--. (4) H20 + 2S02 + 1/2 02 = 2H+ + S206---.]

Jan 1, 1952

By Wesley T. Holmes II, Lloyd H. Banning

Electric - smelting studies were made on titaniferous materials obtained from the Klukwan and Snettisham , Alaska ; Choteau , Mont .; and Iron Mountain , Wyo . , deposits with the objective of determining the feasibility of producing pig iron and an enriched titania slag in one test series and pig iron alone in another test series . In addition , related studies were conducted to determine the amenability of Choteau crude ore to wet -magnetic separation and to determine the quality of steel that could be produced from the titaniferous pig iron . The continuous smelting tests were made in a three - phase , submerged - arc , electric furnace , and the laboratory steelmaking tests were made in a singlephase electric - arc furnace . A continuous , belt - type , wet - magnetic separator was used in conjunction with a ball mill and a spiral classifier in recovering titaniferous magnetite from the crude Choteau ore . Pig irons containing less than 0.05 percent phosphorus or sulfur were readily produced from the titaniferous materials ; iron recoveries ranged from 92 to 98 percent . The Choteau ore was ground to minus 65 - mesh to produce a concentrate containing 60 percent or more iron . The steel produced from the titaniferous pig iron was a high - quality product .

Jan 1, 1964

The Sago Mine Disaster, on January 2, 2006, placed renewed focus on several different aspects of safety in the underground coal mining industry. One area which received increased attention since Sago and other underground coal mining events is the concept of Safety Culture. This report describes the results of a pilot Safety Culture Assessment implemented at a small Appalachian underground coal mine, hereafter referred to as the Mine. The purposes of this pilot assessment were to (a) evaluate the feasibility and usefulness of a methodology for assessing safety culture that had previously been developed for use within other industries, (b) to initiate an investigation into the understanding and defining of the existing safety culture of the underground coal mining industry, and (c) provide meaningful and useful recommendations for the participating mine for their consideration in their ongoing quest to enhance their existing safety culture. This pilot assessment was conducted in July 2007. The report provides information regarding the presence or absence of safety culture characteristics within the Mine. Observations regarding the characteristics of the Mine?s safety culture that should be sustained are presented. Areas in need of attention and management focus to improve the Mine?s safety culture are presented as well as recommendations for moving forward. Safety culture characteristics that are important for the existence of a positive safety culture have been identified to include: - Safety is a clearly recognized value in the organization. - Accountability for safety in the organization is clear. - Safety is integrated into all activities in the organization. - A safety leadership process exists in the organization. - Safety culture is learning driven in the organization. - A process for establishing a strong and effective Safety Conscious Work Environment (SCWE) is in place. Performance objectives are associated with each of the safety culture characteristics and particular behaviors and attitudes have been identified that can be measured to evaluate these objectives. Using a methodology originally developed with the support of the U.S. Nuclear Regulatory Commission, an assessment of selected organizational behaviors and attitudes was conducted to evaluate the Mine in terms of these safety culture characteristics and their associated performance objectives. The methodology involves obtaining a variety of quantitative and qualitative information, using multiple data-gathering methods. The information collected is largely based upon the perceptions of the individuals in the organization. The evaluation is a ?point in time? snapshot of the Mine, but cultural beliefs and assumptions do not change quickly. The feasibility and usefulness of the methodology was successfully demonstrated during this pilot assessment. All aspects of the methodology including functional analysis, structured interviews with accompanying behavioral scales, work observations, and the paper and pencil

Aug 1, 2007

By E. J. Murphy, A. P. Rowles, John C. Holtz

"INTRODUCTION The use of sheaths or hollow cylinders of flame-extinctive materials surrounding cartridges of permissible explosives has been developed during the last few years; the history of sheathed explosives in their salient development in Belgium was treated recently in a publication of the Bureau of Mines. 6/ This development is of great interest in explosives technology, for it holds possibilities of reducing further the ignition hazards that may cause many coal-mine disasters. The township interest in sheathed explosives in this country is attested by the passage of some State laws permitting the use of such explosives on shift 7/; inquiries are received in increasing numbers concerning the effects of sheaths on practical hazards as well as the general technology underlying their use."

May 1, 1943

By STUART R. BRINKLEY, Ruth F. Brinkley

This same phonomonon of diffraction may be transposed into the X-ray domain. All that is necessary is to reduco, in the samo proportion, the wavo length of the light and the diameter of the particlo; thus, with radi- ations whose wave length is of the ordog of angstroms, the dimensions of the active particles go from 10 to 100 A that 18, the dimensions of col- loidal particlos. The evidence of this fact is shown by the following experimental schomo (fig. 1a): A narrow beam of X-rays passes through a thin layer of a modium containing micelles; the photographic film is placed a few centimeters behind the sample, and a small absorbing screen stops the direct beam in order to prevent its fogging the film. The intersect of the direct beam is surrounded by a narrow spot whose blackness decreases with the distance from the center. We will call this the spot of central diffusion (fig. 1b). The phenomenon, in spite of its relatively reat intensity, has been observed only by a few authors, who have simply given a qualitative description without attempting any quantitative de- ductions. This is due to the fact that observation of this phenonenon is not possible with the apparatus generally used to obtain X-ray diagrams, because the parasite foggings in the vicinity of the incident beam are sufficiently important to hide those produced by the sample. With the monochromator, however, used by us to obtain Debye-Sherer diagrams, this parasitic diffusion can be totally suppressed. In this way our attention was again directed to the spot of central diffraction, and we were led to make a detailed quaititative study of it.. then several papers have been published on this subject. Hosemann, using methods of calculation outlined by us, has extended them to the special case of fibrous substances, Kratky, on the other hand, starts from an entirely different theoretical point of view; ho examines the case, not of scattered particles, but of closely packed particles. 6ince We will now describe the experimental methods, summarize the calcu- lations needed in the elaboration of diagrams, and finally review the first results obtained in the vast domain of these new physical-chomical studies.

Dec 1, 1946

By D. Eugene Rannels, Yu-Chen Lee

"Lee, Yu-Chen, and D. Eugene Rannels. Alveolar macrophages modulate the epithelial cell response to coal dust in vitro. Am. J. Physicl. 270 (Lung Cell. Mol. Physiol. 14): L123-L132, 1996.-The response of the alveolar epithelium to coal dust exposure is poorly understood. Coal or other dusts may act on the epithelium directly or indirectly through nearby alveolar macrophages (AM) that produce cytokines and other soluble products. AM and type II pneumocytes (T2P) were thus exposed to dust in coculture to evaluate their possible interactions. Anthracite coal dust PSOC 867 increased synthesis of extracellular matrix (ECM) components by T2P. AM alone did not produce ECM. Similarly, coculture ofT2P with AM (3.75:1) had little effect on epithelial ECM synthesis. In contrast, coculture ofT2P with AM significantly increased PSOC 867 effects on T2P rates of ECM synthesis, ECM fibronectin content, and T2P levels of fibronectin mRNA. AM-conditioned medium did not change the PSOC 867 effect on T2P. Neither control nor PSOC 867-treated AM on Falcon culture inserts (0.45-µm pore size) over T2P stimulated ECM synthesis by either untreated or dust-exposed epithelium. Thus AM-mediated changes in ECM synthesis by PSOC 867-treated T2P require close cell-cell interactions, suggesting a role for cell-cell contact or for short-lived soluble mediators of the AM effects. DEVELOPMENT OF PNEUMOCONIOSIS, a chronic disease of coal workers that results in pulmonary fibrosis and low lung compliance, is associated with inhalation of mineral or coal dust in the work place (14). Although the pathology of pneumoconiosis has been studied extensively, cellular mechanisms that cause changes in lung structure and function are not fully understood. Particulate matter that enters the respiratory system distributes according to size, with larger particles being removed in proximal airways. Dust components of small size may enter distal alveolar region, which is populated by two types of epithelial cells, type I and - type II cells, and by alveolar macrophages (16). Each of these cell types may interact with inhaled particles, but only the effects of coal dust on alveolar macrophages have been studied extensively. Less is known regarding the response of the alveolar epithelium, or of effects on epithelial cell-alveolar macrophage interactions, in the dust-exposed lung.Function of the alveolar epithelium is well known to be influenced by the underlying basement membrane, or extracellular matrix (28). Alveolar epithelial cell extracellular matrix interactions, which may involve modulation of cell migration, attachment, or differentiation (17), are reflected in type II cell morphology, metabolism, secretory activity, hormone responsiveness, lamellar body content, and gene expression (21). The extent to which basement membrane modulates differentiation of the overlying epithelium is determined by both molecular composition and three-dimensional structure of the matrix. Type II epithelial cells in vitro synthesize, secrete, assemble, and degrade a variety of basement membrane components, including laminin, fibronectin, type IV collagen, and thrombospondin (22, 27). How expression of these components is regulated, directly or indirectly, upon exposure of the alveolar epithelium to injury by coal dust or by other particulates remains to be resolved."

Jan 1, 1998

By John E. Shelton

The growing interest in beryllium as a structural material, and its in-creased use in recent years for atomic energy application, have led both government and industry to express concern over the inadequacy of the beryllium resources in the United States and the free world. Contemplated and proposed uses for this unique material will surpass the capacity of the domestic beryllium mining industry to supply raw material, which is presently extracted from relatively small deposits by hand sorting. The need for a simple beneficiation process for beryl ores has long been recognized by the Bureau of Mines, but to date no single process has proved satisfactory for treating deposits containing a sufficient tonnage of beryl ore to warrant commercial exploitation. As a part of the Bureau's continuing effort to develop an economical recovery process, this report describes flotation research on samples of beryl-bearing pegmatites from the George Roebling mine in Connecticut, and the Colony mine in New Hampshire. The study resulted in two methods of treatment to which the ores responded reasonably well.

Jan 1, 1961

By E. K. Stanek

This report contains results of two major efforts related to electrical transients on mine electrical power systems. The first area concerns the use of digital computers to model mine electrical power systems and predict transients or duplicate field recordings of transients. Two existing general purpose circuit analysis programs were used. The first was the TRW Engineering System Simulator or TESS. The second was Electronic Circuit Analysis Program or ECAP. TESS proved to be superior to ECAP in several important characteristics, including system size limitations and modeling nonlinear elements. The second major topic covered in this report is the evaluation of commercially available surge suppression devices. These devices were found to be quite acceptable and guidelines for the selection and placement of surge suppressors were included. The final important item is a listing of the worst-case transients, from a design point of view, for ac and de utilization systems and ac distribution systems.

Jan 1, 1979

By J. Gautam, T. Ong, W. E. Wallace, M. Keane, S. Xing, J. Harrison

"INTRODUCTIONOrganics extractable from respirable diesel exhaust soot particles by organic solvents have been known for some time to be direct acting frameshift mutagens in the Ames Salmonella typhimurium histidine reversion assay (Huisingh, et al). Upon deposition in a pulmonary alveolus or respiratory bronchiole, respirable diesel soot particles will contact first the hypophase which is coated by and laden with surfactants. To model interactions of soot and pulmonary surfactant, we dispersed soots in vitro in the primary phospholipid pulmonary surfactant dipalmitoyl glycerophosphorylcholine (lecithin) (DPL) in physiological saline. We have shown that diesel soots dispersed in lecithin surfactant can express mutagenic activity, in the Ames assay system using S. typhimurium TA98, comparable to that expressed by equal amounts of soot extracted by dichloromethane/ dimethylsulfoxide (DCM/DMSO)(Wallace, et al, 1987). Here we report additional data on the same system using additional exhaust soots and also using two other phospholipids, dipalmitoyl glycerophosphoryl ethanolamine (DPPE), and dipalmitoyl phosphatidic acid (DPPA), with different ionic character hydrophilic moieties. A preliminary study of the surfactant dispersed soot in an eucaryotic cell test system also is reported.MATERIALS AND METHODSSoots D4 and D6 were collected at two different times as scrapings from the exhaust pipe of a diesel tractor-trailer immediately after the engine was stopped. Surfactant dispersions were made by ultrasonic probe sonicating 25 mg of commercially obtained DPL, DPPE, or DPPA into 1O ml of O.85% physiological sterile saline (PSS) for 10 min at 40 watts power. For surfactant dispersions, 2.5 mg soot was mixed into 2.5 ml of the appropriate phospholipid dispersion. Mixtures were sonicated by 40 watts sonicator probe for one min, then incubated in the sonicator water bath for 30 min at room temperature; the mixture was then incubated for one hour at 37C while being rotated continuously. Dilution series were made with saline. For solvent extraction, 2.5 mg soot was mixed into 2.5 ml of DCM and incubated in a sonicator water bath for 30 min at room temperature. The sample was then mixed with 2.7 ml DMSO, placed in a dry bath at 45C, and the DCM evaporated under a stream of nitrogen gas until 2.5 ml of liquid remained. Ames salmonella/microsome assay utilizing TA98 for frameshift mutation was used for mutagenicity testing, with and without S9 activation, as described by Ames et al (1975). Unfiltered sample extractions or dispersions were preincubated with tester cells for 90 min at 37C : 0.1 ml of sample was mixed with 0.5 ml of PSS, or of S9 mixture, and 0.1 ml of an overnight TA98 culture incubated samples were then added to 2 ml of top agar supplemented with biotin and a trace amount of histidine, and overlayed onto Vogel-Bonner minimal media plates. After 48 hours incubation at 37C, revertant colonies were counted. Solvent controls were DMSO, DPL, DPPE, DPPA, and saline. Positive controls were trinitrofluorenone (1 ug/plate), for samples not treated with S9, and 2-aminoanthracene for S9 treated samples (2.5 ug/plate). All samples were assayed in duplicate. Sister chromatid exchange (SCE) assay was performed, following Lett, et al (1981), using V79 cells, of Chinese hamster pulmonary fibroblast origin. Stock diesel sample suspensions were made as 10 mg soot/ml DPL suspension, or 20 mg soot/ml in DMSO. Aliquots of these soot preparations were added to 15 ml of culture medium per sample flask to result in concentrations of 25, 50, and 75 ug soot/ml medium. After 12 hours incubation, 200 ul of 25 uM 5-bromodeoxyuridine (BrdU) was added to each flask. After another 35 hours incubation, 200 ul of 10 ug/ml colcemid were added; and the cells were harvested three hours later. Cells were swollen by hypotonic saline, and fixed twice with methanol/acetic acid, and burst on microscope slides. Cells on the slide were stained with Hoechst 33258, exp"

Jan 1, 1990

By W. A. Stickney, J. W. Town

Batch and continuous - circuit flotation , leaching , precipitation , and electrodeposition studies were made by the Bureau of Mines to determine optimum conditions for treatment of complex mercury - antimony sulfide and mercury- arsenic sulfide ores and concentrates . On the Red Devil ore sample over 95 percent of both the mercury and antimony sulfides were recovered in a flotation concentrate containing 35.6 percent mercury and 21.0 percent antimony . By selective flotation a mercury concentrate containing 71.0 percent mercury and 2.9 percent antimony was obtained with a mercury recovery of 90.4 percent . Leaching results show that , with 150 grams per liter of sodium sulfide and 50 grams per liter of sodium hydroxide , 95 to 99 percent of the mercury , antimony , and arsenic sulfides could be extracted from the concentrates treated . Sodium hydroxide reagent consumption was based on the sulfides generated in the dissolution of the sulfide minerals and on the method of metal recovery used . Selective leaching of the antimony and arsenic sulfides with potassium sulfide dissolved more than 95 percent of either of these two sulfides and 0.5 to 5 percent of the mercury sulfide present . Methods for recovering mercury and antimony from solution were electrodeposition of mercury followed by electrodeposition of antimony , aluminum precipitation of both mercury and antimony , or antimony precipitation of mercury followed by antimony electrodeposition . The method used in recovering the mercury depended on the mercury- antimony content of the solution being treated .Batch and continuous - circuit flotation , leaching , precipitation , and electrodeposition studies were made by the Bureau of Mines to determine optimum conditions for treatment of complex mercury - antimony sulfide and mercury- arsenic sulfide ores and concentrates . On the Red Devil ore sample over 95 percent of both the mercury and antimony sulfides were recovered in a flotation concentrate containing 35.6 percent mercury and 21.0 percent antimony . By selective flotation a mercury concentrate containing 71.0 percent mercury and 2.9 percent antimony was obtained with a mercury recovery of 90.4 percent . Leaching results show that , with 150 grams per liter of sodium sulfide and 50 grams per liter of sodium hydroxide , 95 to 99 percent of the mercury , antimony , and arsenic sulfides could be extracted from the concentrates treated . Sodium hydroxide reagent consumption was based on the sulfides generated in the dissolution of the sulfide minerals and on the method of metal recovery used . Selective leaching of the antimony and arsenic sulfides with potassium sulfide dissolved more than 95 percent of either of these two sulfides and 0.5 to 5 percent of the mercury sulfide present . Methods for recovering mercury and antimony from solution were electrodeposition of mercury followed by electrodeposition of antimony , aluminum precipitation of both mercury and antimony , or antimony precipitation of mercury followed by antimony electrodeposition . The method used in recovering the mercury depended on the mercury- antimony content of the solution being treated .

Jan 1, 1964

By M. M. Tilman

The purpose of this investigation was to determine the effects of small amounts of cobalt in nickel on the tensile properties and hardness of representative types of austenitic stainless steels . Cobalt substitutions for nickel up to 2 weight - percent were made in types 302 and 309 stainless steels . Data were obtained at room temperature for tensile strength , yield strength , percentage elongation , percentage reduction in area , and hardness . In type 302 steels , tensile strength and hardness increased with increased percentages of cobalt , percentage elongation and reduction in area decreased , and yield strength showed little change . Property changes were largely due to the reduction of nickel content rather than to the addition of cobalt . In type 309 steels , only minor variations were observed for the properties investigated ; the effects of the relatively snall cobalt substitutions and nickel reductions were somewhat reduced by the higher total alloy content .

Jan 1, 1964

By M. M. Barr

Rapid expansion of the titanium-metal industry focused attention upon ilmenite as a possible substitute for the more expensive and less abundant rutile in producing titanium tetrachloride. Most of the rutile available for this use is imported. Preliminary studies were undertaken to determine the chlorination characteristics of high-titanium slags produced by electric-arc furnace smelting of alluvial Idaho ilmenite at the Federal Bureau of Mines Northwest Electrodevelopment Experiment Station, Albany, Oreg. Low silicon, calcium, and aluminum contents of the slags enhanced their potential value for chlorination.

Jan 1, 1958