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By W. Rall, A. J. Birkle

The effect of fast-neutron irradiation on the micvo strcture of a common reactor pressure-vessel steel, A212 Grade B, was studied using thin-foil transmission electron microscopy. The dislocation density of the irradiated material is considerably greater than that of the nonirradiated control material. Annealing studies indicated that dislocations and hardness ill the irradiated material annealed out—as docs the radiation-induced embrittlement according to other- investigators— at temperatures STEELS in nuclear reactors are affected by neutron irradiation. In the American Society for Testing Materials (ASTM) A302B and A212B steels commonly specified by designers for reactor vessels, between 650° and 800°F. However, the dislocations and hardness in control samples cold-worked to 9 and 70 pct did not anneal out readily, and a high dis -location density was observed, even after a 1-hr anneal at 850°F. Based on the hypothesis that cllrster defects, rather than the increased dislocation density, are primarily responsible for mdicltiotz-iudziced e)nbriftlen7ent, reconzmendations are made for reducing the susceptibility to such ernbrittlement. exposures at a temperature of 550°F or lower to neutron dosages encountered during a 20- to 30-year life (-3 X 10'' nvt, >1 mev) may increase the nil-ductility transition temperature (NDT) as much as 300" or 400".'9 Therefore, to prevent brittle failures in reactor structures, extreme caution is required to reduce thermally induced stresses during all reactor shutdowns and startups when the temperature is below the NDT of the pressure vessel.

Jan 1, 1964

By Carlos A. Ferreira, Betina Hansen, Marco A. S. Rodrigues, Marcela P. Proença

"Nowadays, the concern with the reduction of industrial pollution has motivated researchers to found out new technologies for treatment of industrial waste. The clean technologies, as electrodialysis, are capable of treating these residues, minimizing the impacts when they are discarded directly on the environment. Membranes of SPS/HIPS, PAniCSA/SPS/HIPS, SPAN/SPS/HIPS were developed using chemical mixture method. Membranes were characterized by Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA) and Scanning Electronic Microscopy (SEM). Membranes were submitted to electrical polarization and to electrodialysis at NaCl and KCl solutions, in order to determine ionic transport through the membranes. Results were compared with commercial membranes. The average percent extraction for Na+ ions obtained by membrane was beyond 20%.IntroductionThe high environmental impact caused by the galvanoplastic industries represents today a world concern(1). In the galvanoplasty, thin metallic layers are deposited on metallic surfaces(2) through chemical methods or electrochemical process. This industrial process presents some disadvantages that limit its utilization, as the generation of toxic effluents containing concentrations of heavy metals usually above the limits allowed for his release in receiving bodies(1), the production of galvanic sludge which is considered hazardous waste and that is very difficult to treat, beyond the high consumption of water (3).Stimulated by the development of new ion-exchanged membranes with high selectivity, lower electrical resistance, and improved thermal, chemical and mechanical properties, the use of electrodialysis in the wastewater treatment has recently gained a broader interest(5). The electrodialysis (ED) is a mass separation process in which electrically charged membranes and an electrical potential difference are used to separate ionic species from an aqueous solution(5). The technique permits the recovery and the reutilization of the waste products from the industrial process, avoiding the discharge of them on the environmental (acting as clean technology)."

Jan 1, 2008

By Shize Jin

Effect of four polyols, namely ethylene glycol (EGL), glycerol (GCL), propanediol (PDL), butanediol (BDL) and three organic acids, namely oxalic acid (OA), malonic acid (MA) and succinic acid (SA) on the current efficiency (CE) and the cell voltage during zinc electrowinning was studied. Galvanostatic polarization was conducted in a supporting electrolyte (SE) containing 180 g dm-³ H2SO4, 60 g dm-³ Zn2+ and 8 g dm-³ Mn2+ at 38°C with magnetic stirring. The imposed current density was 50 mA cm-². The anodes were made of a Pb-Ag alloy and the cathodes were made of an aluminum alloy. The results showed that all the polyols tested in this study decreased the current efficiency and the cell voltage, but the decrease of the cell voltage was not important. Oxalic and succinic acids decreased the current efficiency to a less extent than the polyols, but did not decrease the cell voltage much. The only compound that increased the current efficiency was malonic acid, and its capacity of decreasing the cell voltage was the highest within the seven tested organic compounds.

Jan 1, 2003

By O. C. Blade

The term "Ichtnyol" is a name applied loosely to certain preparations used in pharmacy. These preparations do not occur as such in nature but are manufactured by various chemical processes. Ichthyol is the name trademarked for a product manyfactured by the Irhthyel-Gescllschaft (Cordes Hermanni & Co.) of Hamburg, Germany, and marketed in thin, country by Merck & Co., Inc., (5, 86, 87)3/. Although used in the literature rather loosely, the correctly applied word refers to the product obtained by sulphonating and then neutralizing with ammonia a distillate from the oil retorted from a certain high-sulphur bituminous shale found near the village of Seefeld in the Austrian Tyrol. Due to the fact that fossils of fish and marine animals occur in the limestone associated with the bituminous shale, these deposits have long been known as, the "lchthyolite schistc of Seefeld" ( 55) . The Greek word "ichthys"" for fish and the Latin word "oleum" for oil are the words from which the term is derived. The crude, tarry shale oil, whose distillate is the raw material for the sulphonation process, has been referred to since the Middle Ages as "Dürsten" or "Tirschen" oil, and the term "ichthyel oil" has been used occasionally in the literature to designate the retorted crude oil (92, 93, 106, 117). The first application of the name "Ichthyol" to a particular product is credited to Schröter (35, 129). Various names for products manufactured by sulphonating bituminous distillates have been coined, and in some of these names the root from the word ichthys has been retained. Some of these names can be found in New and Nonofficial Remedies under the heading, Sulphoichthyolate Preparation, and Substitutes (5).

Jan 1, 1938

By S. F. Radtke

The properties and characteristics of lead and zinc have made these metals useful to man in many ways since the days of antiquity. Despite their long history of use, however, these metals have proved to be extremely resilient and responsive to modern needs. New alloys and compounds continue to be developed, adding to the growth of these metals. Consumption data is given for 1969 and compared with one and two decades ago. Trends in major markets also are cited and explained. Uses for lead and zinc which have come into prominence within the past few years are described and explained, with emphasis on the role played by the industry's cooperative research program. Current efforts in the research phase are discussed, with details given on major efforts for both metals, including new alloys, process developments, applications research, finishes, coating, paints and pigments, batteries and fundamental research. A forecast is given of promising new areas and a projection made on a longer term of new applications that may emerge from current research.

Jan 1, 1970

By W. L. Phillips

Stress-train curves were obtained for single crystals of silver, Ag-5 pct Zn, Ag-10 pct Zn, and Ag-20 pct Zn tested in tension and shear at 78°, 195°, and 297°K. At room temperature the critical resolced shear stress gC increased, the length of' the easy-glide region increased, and the rate of' work hardening dwving easy glide decreased with increasixg zinc concentration. The change in the ratio of uc at room temperature to that at lower temperatures was significantly greater for the alloys than for pure silver. It was found that an increment in stress was necessary to continue slip when the slip direction was rotated 60 deg. The magnitude of this increment increased with strain for all alloys, increased with zinc concentration for a given strain, and for a given strain increased with decreasing -temperature. DESPITE its practical importance in improving the mechanical properties, alloying is not fully understood. Except for copper alloys few sets of systematic data are available. Von Goler and Sachs' studied the deformation of Cu-Zn alloys of increasing zinc content and found that, for dilute alloys, the critical resolved shear stress increases linearly with concentration. The range of easy glide was found to increase with increasing zinc content. Schmid and seliger,2 Sachs and Weerts,3 and Osswald4 have shown that with Mg-A1, Au-Ag, and Cu-Ni crystals, respectively, the critical resolved shear stress also varies linearly with concentration. More recently, Linde and his coworkers have investigated the variation of the critical shear stress of copper alloyed with tin , antimony, indium, germanium, silicon, nickel, and gold. They found that the slope of the critical resolved shear stress is related to the change of lattice parameter with composition, and also to the difference in Goldschmidt's atomic diameter between solvent and solute atoms. Garstone, Honey-combe, and creetham6 have shown that similar relationships can be found for small additions of silver, gold, and germanium to pure copper. They found that, with increasing silver or gold concentration, the critical shear stress for glide is increased by alloying, and so is the range of easy glide, which reaches as much as 60 pct for 0.50 pct Ag alloy and 0.62 pct Au alloy, as compared to 6 pct for pure copper of similar initial orientation. They also found that the alloying additions had little effect on the rate of hardening during easy glide, the slope scarcely changing with increasing alloy content. General secondary slip was detected only when the crystals began to harden rapidly. Although the slip appeared to be very fine in the early stages of deformation, coarser slip bands were formed towards the end of the extensive easy-glide range. The present investigation describes the deformation characteristics of single crystals of Ag-Zn containing different concentrations of zinc. Tension and shear testing were used for this study. EXPERIMENTAL PROCEDURE The method of growing the single crystals, sample preparation, and method of testing have been described in detail previously.' EXPERIMENTAL RESULTS A) Tension-Room Temperature. The initial orientations and stress-strain curves of single crystals of silver, Ag-10.0 pct Zn, and Ag-20.0 pct Zn are shown in Fig. 1. It is evident that there is considerable change in the stress-strain characteristics as a function of zinc concentration. The effects of zinc concentration on the critical resolved shear stress for both CU-zn8 and Ag-Zn alloys are summarized in Fig. 2. At all concentrations the resolved shear stress of the Cu-Zn alloys is higher than that of the Ag-Zn alloys. The resolved shear stress increases parabolically as a function of composition for both alloy systems. The length of easy-glide region increased with increasing zinc concentration, Fig. 3b). As the length increased the slope (do/de) decreased slightly, Fig. 3(b). Metallographic investigations demonstrated two significant effects of increasing zinc concentration. First, the amount of clustering increased, compare Figs. 4(a) and (b). The slip lines changed from uniform in pure silver to clustered in the Ag-20 pct Zn and Ag-30 pct Zn alloys. Second, the amount of cross slip decreased as the amount of clustering decreased.

Jan 1, 1968

By K. C. Lau

INTRODUCTION The design of engineering structures such as mine openings in and foundations on rock requires a knowledge of the constitutive laws governing the behaviour of discontinuous and layered rock masses. At the present time there are two main approaches for predicting the stress distributions and displacements in such engineering structures. In one method, the whole of the rock mass is discretized. The behaviour of the components of the rock mass, that is, the joints and the intact rock are modelled using analytical techniques such as the finite or boundary element methods. Typically the intact rock is modelled as a linear elastic material bounded by non-linear discontinuities. An alternative method of analysis is to describe the load-deformation properties of the jointed, layered or even reinforced rock mass in terms of smeared or equivalent homogeneous material properties. Such equivalent material properties may then be used to compute the stress distributions around openings and in foundations using standard methods of analysis such as the finite or boundary element techniques. Once the stresses have been obtained for the equivalent material, the stresses in the individual constituent layers or discontinuities may then be determined. Each approach to the problem has particular advantages. The first method is more likely to yield results which more closely represent the behaviour of the rock mass, since the behavioural responses of both the joints and intact rock are modelled. However, for many large or complicated geologic structures such an approach can become unweildy and uneconomical. In such cases, the equivalent

Jan 1, 1984

By Claude H. P. Lupis, John F. Elliott

QUITE generally an increase in the temperature tends to bring a system closer to ideality. It is reasonable as a first approximation to consider that the excess free energy will vary linearly with the temperature, or: where t may be defined as the "characteristic temperature" of the solution, or the temperature at which the system would become ideal if the results at T were linearly extrapolated. It must be emphasized that consideration of this hypothetical property is an appeal to intuition rather than an established physical concept. The order of magnitude of 7 for dilute solutions will depend on the nature of the solvent; a value of 3000° + 1000°K may be suggested for ordinary metallic solutions. In terms of free energy, entropy, and enthalpy first-order interaction coefficients, differentiation of the above equations with respect to composition leads to The concept of t offers a simple and plausible interpretation of Chipman and corrigan's3 recent empirical correlation between and a for a number of groups of ternary systems 1-24. The authors found that in each group the ratio was approximately constant. The corresponding calculated from their data by Eq. [4] are listed in Table I. The expected order of magnitude is obtained for 7. As noted by Darken,4 if a regular solution is not assumed, thus if utj) # 0, Chipman and Crrigan's results imply that, as T is increased, ultimately changes in sign, Fig. 1. Clearly Eq. [4] is valid only in a limited range of temperatures since at the temperature 7 at which the system becomes ideal not only should become null but also and . Thus, both and are functions of

Jan 1, 1967

By N. H. Wetzel

Railroads, attempting to increase their tonnage without adding new lines, have for some time realized there is a definite relationship between increasd haulage efficiency, and constant communication with each moving unit that operates along their roadbeds. Elaborate radio communication equipment has been devised for this purpose, and is rapidly being installed. Coal mines are faced with similar haulage problems and have sought this constant contact through the use of telephone systems, and dispatcher stations. Often the fixed mine telephone system is unsatisfactory, since the desired person is not present at the phone when needed. Dispatchers lose contact with a motorman as soon as he is out of sight, until he calls in from another telephone. The recently developed frequency-modelated radio phone which makes use of the trolleywire network in a mine as a carrying medium, permits instant and continuous contact between dispatcher and locomotives. The motorman can immediately contact another motor or the dispatcher regardless, of his motor's position on the trollywire system, whether moving or standing.

Jan 1, 1948

By Robert B. Parsons

"For the fourth time in five years, residents of northern Canada have seen a change in the tax treatment of housing and travel costs. The latest changes announced in December 1990 by the Minister of Finance are to become effective in 1991. When will the tinkering stop?IntroductionFor man y years prior to 1987, certain travel and housing allowances received by employees in remote areas were generally considered by Revenue Canada to be tax-free, even though some observers suspected that such generous treatment was contrary to the provisions of the tax legislation. In the mid-eighties, Revenue Canada decided to reconsider the tax treatment of the mining industry's long standing practice of providing housing and travel assistance to these employees. The tax- free treatment was continued by virtue of annual remission orders, but only pending the enactment of legislation which would tackle the issue head-on and layout the rules in black and white to be seen by all. The sequence of events since then may be chronicled as follows:February 26, 1986-Finance Minister Wilson's budget present s the framework for the future tax treatment of travel and housing benefits provided to residents in remote regions of Canada.December 22, 1986-The Minister of Finance announces detailed rules to fill in the earlier announced framework.January 1, 1987-The new tax rules come into effect.April 29, 1988-The Minister of Finance announces the establishment of a Task Force to examine the existing criteria for determining the eligibility of residents of northern and isolated areas for tax benefits.October 27, 1989-The Task Force presents its report.December 7, 1990-Finance Minister Wilson announces a new system of tax benefits for residents of Canada's northern and isolatedregions.January 1, 1991-The new rules become effective."

Jan 1, 1991

By S Grano, M Fordham, H Manouchehri, J Curral

This paper focuses on the impact of high pulp temperature on sphalerite flotation after the zinc regrind circuit in the Zinc Plant of Somincor, owned and operated by Lundin Mining Corporation. In the zinc circuit, the zinc rougher concentrate is reground with forged steel media before flotation with one stage of roughing and scavenging, and three stages of cleaning to obtain a zinc final concentrate (zinc grade >50 per cent). After regrinding, sphalerite flotation has been found to be seriously affected by high pulp temperature which may occur during the summer months. Mineral recoveries were found to be seriously reduced at pulp temperatures above 60¦C. At this high pulp temperature, neither elevated copper sulfate concentration nor a decreased pH alone appreciably increased Zn recovery. However, a combination of these two (eg a decrease in pH from 11.5 to 10.8, and an increase in copper sulfate dosage from 400 g/t to 800 g/t) was found to reduce Zn depression at high pulp temperature. At pulp temperatures below 45¦C, the negative influence of pulp temperature on mineral recoveries was minimal. A systematic series of flotation tests and solution/surface analyses were performed to reveal causes for poor sphalerite flotation at high pulp temperature after regrinding. The decrease in mineral recovery was shown to be associated with variations in the surface species on mineral particles in response to the increased pulp temperature. These variations in the surface species include collector desorption and superficial oxidation to form lead/zinc oxide/hydroxides on mineral particles. The influence of the type of regrinding media on sphalerite flotation at high pulp temperature was also addressed in this work.

Jan 1, 2008

By E. C. Pechin

THE Lucy furnace, owned by Messrs. Carnegie, Kloman & Co., and located on the Alleghany River, on the outskirts of Pittsburgh, is a splendid modern furnace, 75 feet high, and 20 feet bosh. She had been working well on low grade ores of about 50 per cent., producing daily 68 to 75 tons. There was on stock 500 tons of Republic ore, one of the purest and best of the Lake Superior ores, averaging over 68 per cent. of iron, which had been procured for the purpose of making a trial for Bessemer iron. This was charged by itself, and Mr. Skelding, the founder, reports that he did not succeed in getting a single cast when it came down, before the furnace chilled from the hearth to the top of the boshes, some 25 feet. Every effort was made to save her, without avail, and the disagree-

Jan 1, 1874

By M. L. Requa

This paper is abstracted from the report of the Appraisement Committee of the Independent Oil Producers' Agency, of which the writer was Chairman. The other members of the committee were M. V. McQuigg and R. S. Haseltine. To Thomas Cox, engineer in charge of the investigation, and to his efficient staff of assistants, is due the credit for the detail work necessary in carrying out the plan of the Committee. It treats only of the valuation of the lands, wells, and piping, without going into details of equipment and other features. It was recognized, early in the operation, that the value of oil lands was the value of oil to be extracted, and marketed, less the costs attendant thereon. Referring this back to the costs in cents per barrel, it became obvious that surface improvements, absolutely necessary in the production of oil, from wells then drilled; had no separate and independent value aside from the value of the land, but that any excess equipment, not necessary for the production of oil from present wells, such as drilling tools, well casing, etc., should be given a present condition value. In valuing the properties of the Independent Oil Producers' Agency, the Committee has considered the following facts: 1. That from each property there will ultimately be. produced a certain total quantity of oil. 2. That in the production of that oil a certain total quantity of money will be expended. 3. That a certain total amount of money will be received from the oil. 4. That the total net receipts will be the total gross receipts less the cost of development and production. 5. That the present value of the net receipts must be such an amount that when invested by a purchaser it will be returned with 8 per cent. interest additional during the life of the property.

Jan 2, 1918

A novel pressure leaching process for platinum group metal (PGM) feedstocks is described. The process is particularly well suited for treatment of ores or concentrates that are too low grade for economic processing by the conventional smelting/leaching process. Operating conditions have been identified under which gold, the PGM's and the base metals dissolve simultaneously in a pressure leaching autoclave. The product of this leaching process can then be treated by one of several flowsheets, of which the preferred will likely involve solid/liquid separation, followed by precipitation (or adsorption on activated carbon) of gold and the PGM's, followed by copper solvent extraction/electrowinning. Depending on the concentrations of nickel and cobalt, the copper raffinate would either be partially recycled to the autoclave to allow NilCo concentrations to build up, or it would proceed directly to a Ni/Co refinery. This paper deals with the pressure leaching process and the recovery of gold and the PGM's from the pressure leach product.

Jan 1, 2000

By A. Lawson

"Continued and expanded use of underground diesel-powered equipment is considered desirable in order to achieve necessary production capability, particularly when coal becomes increasingly in demand as an energy source. Although diesel engines are derated for underground use, concern has been expressed in many quarters regarding the health effects of worker exposure to diesel-generated particulate and NOx emissions. This concern will increase as Canadian diesel fuel quality becomes heavier and with higher sulphur content. This could result in a requirement to increase ventilation rates by 50%.This paper describes the results of studies of various approaches designed to reduce diesel emissions. Two major approaches have been followed: fuel modification, and emission control hardware development. The results of progress in the development of these approaches will be described.Fuel modification includes the application of water/diesel and methanol/diesel fuel emulsions to the engine. Details of the techniques employed in this approach will be described, together with the effects on diesel emissions. (The paper is concerned with the emission aspects only, not the possible major engine modifications and/ or substitute materials of construction for 100070 methanol.) Use of methanol has the added advantage of acting as a diesel fuel substitute and extender, and there are expectations that underground diesel engines could eventually operate on close to 100% methanol fuel, thereby eliminating particulate emissions. The results of emission control hardware development will also be presented and will include the effects of catalysts, water scrubbers, exhaust filters and exhaust gas recirculation techniques on emissions. A combined systems approach employing a number of these components appears to be the most viable method of controlling the complete array of diesel emissions.This work should culminate in a better understanding of the costs involved in employing fuel modification or emission control hardware relative to the costs of increased ventilation which mpy be necessary to maintain a safe working environment for the underground worker."

Jan 1, 1981

By R. W. Van Dolah

The Bureau of Mines t.ced its investigations into sympathetic detonation of ammonium nitrate (AN) and ammonium nitrate-fuel oil (AN-FO) to define the scaling law for safe separation from detonating AN-FO. Both missile- and non-missile-producing AN-FO donors, weighing up to 5,400 pounds, were employed with acceptors of the same size. The usual cube-root scaling law was not confirmed; exponents for the relationship S = f(Wx) for AN were 0.51 with non¬missile-producing donors and 0.61 for missile-producing donors. For AN-FO an exponent of 0.80 was indicated in the missile-producing case. AN-F0 in polyethylene bags appeared somewhat more easily initiated than bulk AN-FO. The efficacy of barricades in protecting AN charges was investigated. detonation distances were reduced from one-third to one-seventh when filled barricades were employed. The investigation was extended to dynamite with both types of donors. With 1,600-pound missile-producing donors and an equivalent weight of dynamite, initiation would be expected in 50 percent of the trials at 167 feet. The corresponding value in the non-missile case was 67 feet. The data developed in this program of sympathetic detonation will allow the development of a rational set of safe separation distances for AN, AN-FO, and explosives.

Jan 1, 1966

By P. Chris Pistorius

"Ilmenite smelting involves partial reduction of iron oxide from a slag consisting mainly of T1O2, T12O3 and FeO, yielding as products iron (with approximately 2% carbon) and titanium slag. Slag purity requirements preclude any fluxing additions, and the aggressive nature of the slag necessitates a furnace freeze lining. Large departures from thermal and chemical equilibrium hold in the smelter, with possible implications for process stability. The slag is approximately 150K. hotter than the metal, which means that the metal temperature is below the slag melting point; this difference in temperature has been shown to lead to formation of a solid TisOs-rich layer between the slag and metal. Recent equilibrium measurements have confirmed that the slag and metal are not in chemical equilibrium either, with significantly more reducing conditions in the metal than in the slag. After solidification, the pseudobrookite slag structure is metastable below approximately 1400K, and may transform upon slight oxidation.IntroductionThe natural mineral ilmenite is the main source of titanium, which is mainly used to produce Ti02-based pigments. Ilmenite has the ideal formula FeTiC>3, but natural minerals can be partially oxidized (to contain some Fe3+), and typically contain MnO and MgO as well, together with associated silicate minerals. Smelting is one of the methods to upgrade ilmenite for subsequent T1O2 pigment production; smelting involves partial reduction of FeO to form metallic iron as a byproduct and titanium slag as the main product. Reduction is typically controlled to yield a slag which contains around 10% FeO, 85% (Ti02+Tij03) and 5% impurity oxides (mainly MnO, AI2O3 and S1O2). An example of a typical average slag composition from reduction of South African ilmenite is shown in Table I. As this indicates, a significant side reaction is reduction of some T1O2 to T12O3. The relative extents of reduction of FeO to Fe and of Ti02 to T12O3 are such that the slag stoichiometry is close to that of the pseudobrookite phase [1]. Pseudobrookite has the structure AB2O5 (where ""A"" and ""B"" are different cation sites); the phase which makes up the bulk of solidified titanium slag has the AB2O5 structure and stoichiometry [2], and can be viewed as a solid solution of FeTi20s, T13O5, ÌçÔÀ2è5, MgTi20s, AI2T1O5 and C^TiOs [1]. This solid-solution phase is referred to as ""pseudobrookite"" or ""M3O5"" in this paper."

Jan 1, 2012

By M. Gaft, G. Panczer, R. Reisfeld, L. Nagli

Laser-induced luminescence and breakdown spectroscopy methods appear to be a good tool for real-time evaluation of dolomite content on moving belt. The distinctive feature for time- resolved luminescence is Dy3+ emission in apatite, which is excited by 251 nm laser light and detected with delay time of 5 ms and gate width of 1 ms. The distinctive features for breakdown spectroscopy are 604 nm line of F and P in apatite and 518 nm line of Mg in dolomite. The representative sampling of more than 200 pebbles has been studied by both methods. By luminescence method 100% of dolomite will be identified, while approximately 15-20% of apatite with extremely week Dy3+ luminescence may be mistakenly counted as dolomite. By breakdown spectroscopy the identification is 100% correct both for dolomite and for apatite.

Jan 1, 2002

The National Institute for Occupational Safety and Health (NIOSH) conducratory and field tests to evaluate the effectiveness of dust collector bags for reducing dust liberation and operator exposure from a roof bolter?s dust collection system. The laboratory tests evaluated the bag?s effectiveness to contain dust and the effect on canister filter loading in both a bag and bagless condition. The dust emissions from the collector?s exhaust were also measured in each condition during laboratory testing and show that nearly 100% of the test dust fed into the collector was captured by the dust bags. Loading and pressure drop on the dust collector?s canister filter is greatly decreased when using the bags, enabling longer periods of drilling without filter removal/cleaning. The field results showed that, even though dust standards were met, respirable dust in exhausted emissions was reduced around the bolter. Laboratory and field results show that benefits from use of the bags are realized in all areas of operator exposure.

Jan 1, 2008

This brief resume of events, transpiring in Mexico, culled front the daily New York newspapers, since the last Bulletin-went to press, does not indicate any degree of improvement in the situation. RECORDS OF 217 MEXICO KILLINGS SUBMITTED BY AMBASSADOR FLETCHER Henry P. Fletcher, the American Ambassador to Mexico, called as the first witness before the Rules Committee of the House which has begun a preliminary inquiry into conditions in Mexico, which, it, is believed, will lead to a thorough and far-reaching investigation by a joint Senate and House Committee of the entire Mexican problem, submitted a list of the names of Americans officially known to have been killed in Mexico, a majority of them murdered in cold blood, since the overthrow of Porfirio Diaz by Maderoin 1911. The list contains 217 names and in comparatively few instances do the records show that arrests were made by the particular Mexican faction that happened to be in power where the crime was committed. In only one instance, that of John B. McManus, who was killed in March, 1915, was reparation made. It is significant that McManus was killed by Zapatistas, and Zapata officials apologized for the crime and paid to Mrs. McManus a voluntary indemnity of $20,000 in gold. Of the 217 persons listed as victims of the Mexicans, .137 perished since Carranza came into power. The list, it was admitted, is not complete. It was evident, says the New York Times, that the Ambassador considered the situation very serious.

Jan 9, 1919