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By S. Castro, L. Gutiérrez, L. Uribe

"Use of lime in seawater as a pyrite depressant decreases Mo recovery in flotation of Cu- Mo sulfide ores. When technology that uses sodium metabisulfite (MBS) to depress pyrite is applied, the process is carried out at pH 6.5–7.5, the range where Mo recovery is higher than the usual pH 11.0–12.0 when lime is applied. Redox conditions and chemical reactions involved in depression mechanisms of pyrite by MBS, or sodium sulfite, in seawater are investigated and discussed based on the acidifying effect of MBS, oxidation of sulfite ions by dissolved oxygen, and the role of catalyst of some metal cations (e.g., copper ions) adsorbed on pyrite’s surface.RÉSUMÉ L’utilisation de chaux dans de l’eau de mer comme agent déprimant de la pyrite réduit la récupération de molybdène (Mo) dans la flottation de minerais sulfurés de Cu-Mo. Lorsque l’on applique la technologie utilisant du métabisulfite (MBS) de sodium comme agent déprimant de la pyrite, le procédé se fait à un pH de 6,5 à 7,5, gamme dans laquelle la récupération de Mo est supérieure au procédé habituel utilisant un pH de 11,0 à 12,0 lorsque l’on applique de la chaux. Les conditions de réduction-oxydation (redox) et les réactions chimiques impliquées dans les mécanismes de dépression de la pyrite par le MBS (ou sulfite de sodium) dans de l’eau de mer sont étudiées et débattues sur la base de l’effet acidifiant du MBS, de l’oxydation des ions sulfites par de l’oxygène dissous et du rôle de catalyseur de certains cations métalliques (par exemple les ions de cuivre) adsorbés à la surface de la pyrite. INTRODUCTIONThe copper industry is aware of the difficulties of floating Cu-Mo sulfide ores in seawater. Molybdenum recovery is partially depressed when lime is used to reject pyrite. In plant practice, sodium metabisulfite (MBS) has been demonstrated to be the most promising option for replacing lime in seawater."

Jan 1, 2017

By G. J. Heferen, A. Pranowo, N. J. Aslin, P. O. Eriksson

Glencore Technology (GT) has over four decades experience supplying stainless steel cathode plates (“cathode plates”) to the electro-refining and electro-winning industry. Cathode plates are typically the single biggest capital investment in a refinery. Refineries may view cathode plates as fixed asset or consumables depending on their operational characteristics. This paper examines the issue of cathode plate life and the strategies and philosophies used by different plants in the management of their cathode plate asset. Some plants operate with their original plates after more than 20 years. Others accept high turnover and regular maintenance as normal operating practice. Reference data are provided on plate life for various operating plants including benchmark plants achieving best-practice plate life and operating cost. The role of the electrode handling equipment on cathode plate longevity is also examined, including latest developments in Cathode Stripping Machine, robotic copper stripping, and full-automation production cranes. The ability to identify and manage the population of plates in service is also critical for maximising plate life and minimising its overall operating cost. This paper discusses a novel and unique RFID system for tracking and managing cathode plate inventory. INTRODUCTION Permanent cathode plates The adoption of permanent stainless steel cathode electrodes in the electro-refining of copper was the most significant process development since the first commercial electro-refineries were built in the late 19th century. It provided significant improvement over the labour intensive and complicated starter sheet system. Copper grows over the permanent cathode blade for a number of days before being stripped, and the permanent cathode can be returned straight back to cells for the next cathode cycle. Glencore Technology (formerly Mount Isa Mines (MIM), then Xstrata Technology) has been manufacturing permanent stainless steel cathode plates from the late 1970s with the birth of ISA PROCESS™, and the Kidd process that came one decade later. Invented and commercialised by Mount Isa Mines, the ISA PROCESS™ was first implemented into Copper Refineries Limited (CRL), Townsville, in 1978. The KIDD PROCESS by Falconbridge evolved in the 1980s and was first implemented into the Kidd Creek Tankhouse, both operations converting from traditional copper starter sheets.

Jan 1, 2019

By K. Chattopadhyay

Fluid flows in metallurgical reactors play a vital role on liquid metal cleanliness for both ferrous and non-ferrous metallurgy. Thus, it is absolutely critical to understand different fluid flow mechanisms, and the use of computational methods to model the complex non-isothermal, turbulent, single- and multiphase-flows, has to be appreciated. The present case study emphasizes on controlling the flow of liquid steel in a tundish and enhancing liquid metal cleanliness. CFD modeling was used to build a robust mathematical model, and effects of flow control furniture and non-isothermal conditions were analyzed. The mathematical model was validated against water model experiments. Parameters that were conducive for inclusion removal were identified and implemented in the plant. Some flow control devices could increase inclusion removal to a great extent compared to the existing configurations. In cases, where a hot ladle was poured into a relatively cooler tundish, inclusion removal was better, whereas results were catastrophic in cases where colder liquid was poured from ladle to the tundish. Similar techniques can be applied for other liquid metals including light metals and non-ferrous metals.

Jan 1, 2015

"In response to mine head grades declining and orebodies becoming more complex, Glencore Technology has developed an alternative method for recovering economic minerals once leached into solution, rather than relying on conventional flowsheet options. The method involves the precipitation and separation of base metals from solution with limestone or lime. The final grade of these precipitate is not usually high enough to attract favourable terms of sale due to dilution from gypsum and sulphate salts. A set of operating conditions have been developed to allow the separation of the base metal precipitate from gypsum by exploiting the difference in particle size. A high-grade oxide product can be easily separated from the gypsum stream at very low cost. This process was originally developed by Glencore for zinc and copper systems. This paper reports on the successful application to nickel and cobalt, and this process has significant advantages over the incumbent precipitation process utilising magnesia.INTRODUCTION During evaluation of transitional and oxide zinc ore deposits during the 1990’s, Noranda Inc. (now Glencore) developed a sulphate based ore leach process to extract zinc into solution. For flowsheet development, conventional schemes dictated that once the zinc was dissolved in an acidified solution it was recovered by means of purification or solvent extraction followed by electrowinning and casting to produce zinc ingots. The deposits Noranda evaluated were high grade but had a relatively short mine life (10 years) and economic analysis showed that the projects couldn’t sustain the investment of a full zinc refinery. Compounding this problem was the lack of power supply infrastructure and the high power cost in the region. Noranda then evaluated alternative means of recovering zinc from solution. Laboratory testwork showed that a high-grade zinc precipitate (+50 wt% Zn) could be produced as an oxide, carbonate or sulphide by contacting acidified zinc sulphate solution with a number of reagents including soda ash, sodium hydroxide, and sodium hydrogen sulphide. Economic evaluation showed that the cost of the reagents are prohibitive, especially when the final product is still a metal intermediate (ZnO, ZnCO3 or ZnS). Noranda then continued to focus on fine zinc oxide precipitation for supply into the automotive tyre industry as this product would attract favourable terms of sale as a premium on Special High Grade (SHG) zinc."

Jan 1, 2017

By A. P. Sasmito

It is well known that underground miners are exposed to one of the most dangerous working environments on earth. As mine delve deeper, the geological factor, mine position and climate condition as well as heat generation from mining machine give rise to the mine operating temperature. This, in turn, has an adverse effect on the environment and thus leads to higher operating costs. Careful estimation and design of air flow rate, spray system, cooling load and additional ventilation auxiliary equipment are of importance to ensure safety, comfort and productivity whilst maintaining low operating cost. A computational fluid dynamics simulation approach is employed to examine underground mine ventilation in a 36 m cul-de-sac of tunnel of coal mine. The model predictions in the turbulent range were validated by comparison with published data. Different turbulence models were tested to select one that yields adequate accuracy and is computationally efficient. Effects of the following parameters are evaluated: tunnel geometry, air flow rate and inlet air temperature. The objective of the simulation is to arrive at an optimal strategy for ventilation and thermal comfort at low cost.

Aug 1, 2013

By Tong Guan, Guangqin Fu, Lihong Deng, Yuanlin Chen, Xiaotong Zhou

"In natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the content of MoO3 varies from 2% to 10%. As a result, the flotability of seyrigite (scheelite with molybdenum) turns to be weaker. One seyrigite mine, which has been built for 3 years,still could not produce qualified seyrigite concentrate due to the weak flotability of seyrigite (Mo-bearing scheelite) in raw ore. In our experimental research, through adopting new seyrigite collector TA-3 and advanced mineral processing technology, the seyrigite concentrate with a grade of 65.62% WO3 at a recovery of 87.47% was obtained for the raw ore containing 0.19% WO3 and 0.074% Mo. By applying the new technical achievement, for the raw ore containing 0.272% WO3, the seyrigite concentrate assaying 68.03% WO3 with a recovery of 77.56% was obtained in industrial production.INTRODUCTIONIn natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the scheelite is changed to be seyrigite (Ca[(W,Mo)O4]) (Ma, Bian, & Wang, 2013). The content of MoO3 in seyrigite varies from 2% to 10% usually, the content of MoO3 in some of the seyrigite even reaches 34%. The flotability of seyrigite is weak (Zhang, 2007), and the seyrigite is difficult to be recovered by flotation with common collectors and regulators. One scheelite mine in Anhui China, which is a skarn type seyrigite mine, has not produced qualified concentrate yet since 3 years it has been built due to the limit of beneficiation technology. Therefore, it is necessary to conduct research on the collectors with high efficiency and developing advanced processing flow for this kind of ore."

Jan 1, 2016

By Julian Baldry

"This paper begins by describing the parameters of high-speed underground tracked drifting operations and the mucking cycle, and-discusses their variations. The railbound Haggloader 8HR is then described, as well as the Hagglund shuttle trains, outlining the advantages and disadvantages of the system. A comparison with conventional mucking operations is then given.IntroductionDrift and tunnel rounds are mucked by one of two major methods, either trackless with diesel loaders and trucks or with track loaders and cars. The aim of this paper is to compare the conventional tracked mucking cycle with the Hagglunds system alternatives.For many years, the traditional method of attacking the mucking cycle has been with a rocker shovel loader, a string of cars and a locomotive. The rocker shovel loads the first car and when full it is taken to a side drift, cherry picker or some other transfer point and is exchanged for an empty one. This empty car is then pushed back into the face and the loading continues until all cars are full . Then the whole train is taken out to a dump point where the cars are emptied. Normally the train's capacity is less than the volume of the muckpile, so the cars go back to the face. This loading cycle is repeated until all muck is removed from the heading. The last train out from the heading usually takes the loader and parks it in a side drift before continuing on to the dump where the cars are emptied.This simplified version of the traditional loading cycle excludes the ancillary work elements such as track laying and so on, but does point out that the cars must be transferred when full and that the whole train normally makes at least two round trips from the dump to the face. The prime aim in drifting is to cycle a round whithin a working shift which necessitates that no one part absorbs so much time as to prevent the completion of the cycle.Mucking, drilling and loading and the ancillary work such as rock bolting, vent and service pipe hanging typically each take one-third of the available work time. Drilling or mucking can and often do, because of various factors, take nearly half of the total cycle time. Once any segment of the operation starts to take this portion of the shift, the likelihood of missed rounds becomes increasingly greater."

Jan 1, 1981

By Z. S. Shao, X. Z. Li

"Sub-critical crack growth plays an important role in long-term creep failure in brittle rock. Based on micromechanics established by using relationship between micromechanical wing crack growth model and macroscopic strain, and comparing theoretical model with testing results, a method, which applies the theory to real rock, is suggested in this paper. Using this method, properties of creep, damage and progressive failure in brittle rock are investigated. Effects of stress state on creep failure time and steady-state creep rate are analyzed and graphically presented. The results are helpful to support structure design and service life evaluation of underground structures with high geostatic stresses. INTRODUCTIONDuring the long-term operation in underground space with brittle surrounding rock, due to chemical action between pore water and rock, the failure of rock often occurs at stresses below its short-term failure strength, which brings serious effect on the long-term stability of underground structure. Thus, the long-term strength of brittle rock attracted wide interests of scholars around the world. The static fatigue limit was predicted by exponential function that is derived from abundant experiment data of stress level and failure time(Schmidtke & Lajtai, 1985), and similar result by relationship between stress state and failure time was also suggested (Lau & Chandler, 2004; Aubertin et al., 2000; Sangha & Dhir, 1972). According to relationship between steady creep rate and stress state during creep, a critical stress that transforms steady-state creep to accelerated creep was studied and the long-term strength was suggested (Tsai et al., 2008; Ma & Daemen, 2006; Lajtai et al., 1991). Based on the results of experiment in compression, the long-term strength of rock was defined by stress at volume strain reversal. When applied stresses are larger than the long-term strength, the microcracks in the rock will grow constantly, damage of rock will increase and failure of rock will occur finally (Chandler, 2013; Bieniawski, 1967; Brace et al., 1966)."

Jan 1, 2015

This paper describes the results of a laboratory study on the upgrading of Algoma siderite by the amine flotation of silica and silicate gangue. The experiments indicate that a virtually complete removal of silica is possible in a rougher flotation con-ducted in tap water at natural pH, without prior desliming of the ore. Grinding considerably finer than the apparent liberation size is essential for maximum silica rejection. A cationic collector, Aeromine 3037, gave best results when used in combination with a modifier. Of the several modifiers tested, a Dutch potato dextrin, Dextrin 4356, was found to be the most effective. Both iron recovery and the grade of the final iron product are enhanced by floating the pyrite contained in the ore prior to the amine flotation of the silica, and by scalping the magnetics from the silica concentrate. F OR over twenty years, the Algoma Ore Properties Division of The Algoma Steel

Jan 1, 1963

By G. M. Ritcey

The recovery of copper from low-grade solutions res ulting from dump leaching is well known, whereas the recovery from highly concentrated copper solutions has not been practiced. This paper discusses the use of Ashland Chemical's Kelex 100, a substituted quinoline, for the recovery of copper from solutions resulting from leaching copper-nickel concentrates. A flow sheet is described, and an economic comparison shows Kelex 100 to be superior to either the LIX 64N or LIX 70 reagents of General Mills for the recovery of copper.

Jan 1, 1973

By B. R. MacKay

Introduction The Corbin coalfield is one of the smallest, and at the same time one of the principal, producing bituminous-coal areas in southeastern British Columbia, and is unique on account of the great original thickness of one of its coal seams and the remarkable concentration of coal in a small area that has occurred through intense folding and faulting of the measures. These are such that the deposit has been referred to at times as "the world's thickest coal seam" and as" a mountain of coal." The determination of the number, thickness, and character of the seams present, and the structure, extent, and geological relationship of the several deposits, are of vital interest both to the operating company in its endeavour to evolve the most efficient method of mining these exceptionally thick deposits and to the Government in estimating the coal resources of the different fields. With the object of ascertaining these data the writer was assigned in 1930 to geologically map and study the Corbin coal deposit. A topographic map covering Coal mountain and the immediate vicinity on a scale of 1 inch =800 feet, with a contour interval of 25 feet, made by the Topographic Division of the Geological Survey, served as the base for the geological mapping.

Jan 1, 1931

By Bunting S. Crocker

This paper reviews the trends in the past two years in autogenous grinding throughout the world. It covers rock grinding in South Africa, Sweden, Canada, the United States, Finland and Germany. To properly orient the discussion on this subject, the paper attempts to define and classify the scope of autogenous comminution. As this is a relatively new subject, there is often considerable confusion regarding the various practices, which sometimes differ widely. By clarifying the types and forms, we hope to help clear up this con-fusion. Autogenous grinding is being carried out, throughout the world, either in mills grinding in water or solution or in dry mills using air classification to remove the finished material. The wet grinding, particularly, can be divided into: (1) (2) (3) Primary autogenous grinding, or "run-of-mine" grinding. Secondary autogenous grinding or semi-autogenous grinding or rock pebble grinding. Combination processes. -This covers plants in which pebbles made in the primary mill are re-moved and used as grinding media for fine grinding in secondary mills.

Jan 1, 1963

By J. J. Laffin

In the pursuit of comfort and safety, the wonders of science have given us controlled heating and cooling, thus enabling us to enjoy all the aspects of present-day living to an extreme never previously •envisaged. Man's attempt to conquer the elements largely involves con-trolling the temperature around him. Without having conquered this aspect, his body energy would be consumed in trying to maintain physical comfort, rather than being invested in the explorations which have resulted in man's control over the forces of nature. The indirect methods used to obtain the most agreeable temperature environment were developed because of the natural tendency to strive for increased safety, convenience and comfort. Until the twentieth century, when heat generated by atomic fission became a reality, man's only source of heat, except for that of the sun, came from his discovery of fire.

Jan 1, 1962

By B. R. Johnston, K. D. Streeter

"ABSTRACTCoal Mountain Operations is the newest of Fording Coal’s operations although it is the oldest in terms of its historical production. In October, 1994, Fording purchased the former Corbin Creek/Byron Creek Mine. The mine is located in southeastern British Columbia, approximately 150 air kilometers from Calgary, Alberta. It was first developed in 1905 and has gone through a variety of owners in its 90-year history.This paper will deal with the remobilization strategy and the mining plans for the operation which are being implemented to make this operation competitive in the world export coal market. IntroductionIn October 1994, following a due diligence process, Fording Coal Limited purchased Coal Mountain Operations from Corbin Creek Resources, an employee group which had previously owned the mine. The purchase awarded Fording Coal Limited with 100% of the assets, and control of all the coal leases at Coal Mountain.The mine is located in southeastern British Columbia, southeast of Sparwood at the hamlet of Corbin, (Fig. 1).Rehiring of laid-off employees started in November 1994, with mining activities also recommencing in November. The coal preparation plant was restarted in December with one shift, went to two shifts in January 1995, and had four-shift, full-time operation in April 1996."

Jan 1, 1997

By H. D. B. Wilson

"IntroductionRECENT ADVANCES in geo-chemistry and in •our knowledge •of crystal structure provide a key which enables us to create a systematic picture of the genesis of many ore deposits. This genetic scheme may be used with confidence in assessing certain types of orebodies and may be of some aid in actual exploration, since it affords a rational explanation of the dependence of the composition •of the ore minerals on that of the rock type in which they occur with which they -are •associated. For purposes of the present paper, .the elements chosen are •chromium, vanadium, iron, and titanium. The oxides of all these metals occur in deposits of similar or related type, and it is proposed to show that, for each, the composition of the •ore mineral is related to •the composition of the enclosing :rock, and that one of the principal factors controlling the composition of the ore is the ionic size of its constituent elements.Geochemical PrinciplesThe crystals of the rock-forming silicates and of the magmatic oxide minerals are essentially ionic types. This means that they are composed •of oppositely charged ions such as Mg²+ and 0²-, which are held together by electrostatic attraction. The ions of each element are spherical, with characteristic size known as the ionic radius. Crystals are built up by the packing of these spheres in the most stable arrangement compatible with the size and the size and valence of the ions• involved.Many of the principles governing the formation of ionic crystals are •simple ,and logical."

Jan 1, 1953

By M. A. Gomez, V. Yahorava, J. A. Strauss

"It is accepted widely that pressure oxidation (POX) is the most appropriate technology for processing of arsenic containing refractory gold ores. However, studies on the stability of various iron-arsenic precipitates formed during POX are limited. Since the behaviour of these phases could have significant practical implications for gold processing plants, it is important to study them in isolation. This paper compares two synthetic precipitates, basic ferric arsenate sulphate (BFAS) and basic ferric sulphate (BFS) in terms of their formation, behaviour during hot curing and cyanidation, as well as their environmental stability. BFS and BFAS were synthesised hydrothermally at 205°C and their mineralogy was confirmed using various techniques. During synthesis, the addition of H3AsO4 into an aqueous Fe2(SO4)3-H2SO4 mixture significantly decreased the iron yield to BFAS in comparison to BFS under equimolar initial iron and acid concentrations. The BFAS dissolution kinetics was slightly faster, as compared to BFS, during subsequent hot curing. Cyanidation test work on the washed synthetic precipitates indicated that the lime consumption of BFAS was three times lower in comparison to BFS, while cyanide consumptions were comparable. Fresh BFS and BFAS precipitates, as well as their cyanidation residues, were found to pass the respective environmental tests in terms of arsenic release.INTRODUCTION Pressure oxidation (POX) is generally viewed as the most appropriate technology for the processing of arsenic-containing refractory gold ores due to the stabilisation of arsenic in the leach residue (Dutrizac & Jambor, 2007; Gomez et al., 2008; Harris, 2003; Collins, Berezowsky, & Weir, 1988). Detailed laboratory studies indicated that several Fe(III)-arsenate type compounds may be formed under typical conditions of autoclave treatment of refractory gold ores (Swash & Monhemius, 1994; Dutrizac & Jambor, 2007; Gomez et al., 2008, 2010; Gomez, Becze, Cutler, & Demopoulos, 2011). The basic ferric arsenate sulphate (BFAS) phase (Gomez et al., 2008), also known as Type II ferric arsenate (Swash & Monhemius, 1994) or Phase 3 (Dutrizac & Jambor, 2007), is one of the most common arsenic-bearing products (Harris, 2003; Dutrizac & Jambor, 2007). BFAS precipitation is viewed as one of the best routes for arsenic stabilisation and performed equally well to scorodite during environmental stability tests (Harris, 2003; Swash & Monhemius, 1994; Dutrizac & Jambor, 2007; Gomez et al., 2008, 2011)."

Jan 1, 2017

By M. J. Sapko, R. W. Watson, E. S. Weiss

The relative incerdivity of several blasting agents was evaluated in the Bureau's Bruceton Experimental Mine (BEM) . The minimum charge weights resulting in the ignition of predispersed oil shale dust clouds were measured for each of the explosives. A 400 g unstennned charge of ANFO (ammonium nitrate-fuel oil) was sufficient to initiate an oil shale dust explosion, whereas a 1000 g unstenuned charge of an emulsion blend did not ignite the dust even with the addition of 4% methane gas. Several stenuning materials were evaluated in the BEM for their effectiveness in preventing the ignition of near stoichiometric methane-air mixtures. Water stenuning was superior to all other inhibitors tested against methane. Explosibility testing of fine sulfide ore dust in a 20 L chamber and in the BEM show that the dust is capable of propagating an explosion given nominal concentrations of 700 to 800 g/m3. Results are encouraging and irrlicate that there is merit in pursuing explosive composition as a means of reducing ignition probability of oil shale and sulfide dust clouds generated during nonnal blasting operations. The proper selection of explosives and stenuning materials should significantly reduce the probability of secondacy dust explosions in oil shale and sulfide ore mining.

May 11, 1988

By William B. Coker, Vladimir J. Sopuck, J. S. Fox

"Preliminary investigations indicate that organic lake sediments offer some potential for gold exploration within the Canadian Shield of northwestern Saskatchewan. It is also apparent that certain precautions must be taken.Gold is primarily related to the organic fraction of the lake sediments, which, although giving consistant Au contents to those sediments, may restrict the dispersion of Au within the lake itself. It may be necessary to carry out selective extractions on the lake sediments to differentiate between Au related to organic sequestration, indicative of hydromorphic and/ or chemical dispersion, and Au related to inorganics, indicative of mechanical dispersion.Lake sediments are probably only of use for very detailed exploration (i.e. every lake). One to three samples per lake should be appropriate, although a single centre-lake organic-rich sediment sample may be adequate in very small lakes. Each lake sediment sample should be analyzed at least twice and the analytical data carefully monitored and evaluated.The use of As in lake sediments as a pathfinder element for gold is applicable in the search for certain types of gold occurrences.Following detailed lake sediment sampling, basal till sampling can possibly be used to localize areas of potential gold with or without base metal mineralization."

Jan 1, 1982

By Q. F. Wang, M. H. Lai, T. Q. Liu, G. G. Dong

Compared with the traditional pre-treatment process, biological oxidation process has many advantages including higher gold recovery, less cost, easier operation. The bio-oxidation reactor is the most important equipment for biological oxidation process. In this paper, the characteristics of biological oxidation are investigated, and the design principles are proposed based on laboratory tests. Both increasing the tank height and taking new inflation system can enhance higher dissolved oxygen. The new type of large-scale industrial bio-oxidation reactor is designed, which is 9.5 m in diameter and 10 m in height. The bio-oxidation reactor metallurgical performance has been tested by industrial-scale experiment. The slurry of flotation concentrate is divided into two parts to feed two bio-oxidation reactors. The feeding rates of two reactors are adjusted on the basis of getting the same content of S, Fe, As in overflow. The result shows that the feeding rate of the new type of 700 m3 bio-oxidation reactor is 3.72 m3 per hour, and the feed rate of the conventional 700 m3 bio-oxidation reactor was 3.23 m3 per hour. The processing capacity of the former is 15.2% higher than that of the later, which demonstrates the new type of bio-oxidation reactor has higher oxidation rate.

Jan 1, 2015

By Robert F. Shurtz

This paper discusses and compares methods of statistical analysis of the information relating to the evaluation of an asbestos deposit. From a study of 10-ft. lengths of drill core, the separate effects of visual evaluation errors were determined, as well as the deviations between evaluators and the deviations produced by a slight displacement in the center lines of the check drill holes. The importance of careful statistical analysis of such information is stressed.

Jan 1, 1966