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By B. S. Ignasiak, B. N. Nandi, D. S. Montgomery

The growing need to measure the extent of weathering of coking coal in storage and in transit prompted the comparison of the dilatation of coking coal on heating, which is known to be a sensitive index of oxidation, with the composition and volume of the gases produced by a mild pyrolysis of the same coal. It was found that the pyrolysis method had the advantage in that it could be used to study coking coals in advanced stages of oxidation, when the swelling properties had been largely destroyed. Of the various constituents in the pyrolysis gas, the most sensitive indication of coal oxidation was the volume of carbon monoxide evolved per gram of coal. For the coals examined, this index appeared to be at its best when the temperature of pyrolysis was approximately 35oC.

Jan 1, 1970

By B. Misra, B. S: Sastry, Kollu S. Rao

"This paper reports the results of a finite element study of the geothermal heatflow into dry mine airways. For isotropic and unsteady state conditions the heatflow into mine airways is studied for a range of surface heat transfer coefficients between rock and air, and age of the airway. Dimensionless temperature gradient values are presented in tables for different values of Boit and Fourier numbers and the results are compared with Starfield tables and Gibson algorithm. It is found that Starfield tables have consistently over-predicted the G values with errors ranging from 2% to 10%. The differences between results obtained from the finite element study and the G values calculated from Gibson's approximation method are mapped. The small error values over a large range of Fourier and Biot numbers confirm the suitability of Gibson's algorithm to rapidly calculate G values for estimating the heat transfer from surrounding rock to mine air.IntroductionIn many underground mines heat is a major problem, and the provision of acceptable working conditions requires considerable expenditure on ventilation systems. The rational design and operation of these systems depend upon an understanding of the various sources of heat in the mine. The natural source, i.e. geothermal heat, contributes up to 80% of total heat added to mine air and it is difficult to analyze and predict the heat owing to a number of influencing variables. The problem of geothermal heat flow has been studied by many investigators (Goch, 1940; Starfield, 1966; Hemp, 1987; Amano et al., 1982; McPherson, 1986).The primary concern of this paper is to develop a better ready reference dimensionless transient temperature table for estimating heatflow at any stage of mine airway life."

Jan 1, 1994

By E. Ghali, J. F. Dorion

This paper presents the results of on-going investigations on the influence of corrosion on the performance of support systems in selected underground gold mines. Rock support is exposed to various conditions that can be aggressive. Samples of corroded support were analysed using SEM and photomicrography to determine the main corrosion forms. Tests are on-going in controlled corrosion chambers to qualify and quantify the impact of rock and minerals particles on steel corrosion. As more data become available these relationships can lead to useful information on the choice of support systems and reliable estimates of their longevity.

Jan 1, 2011

By Hamid-Reza Manouchehri

Coarse particles flotation is controlled by detachment (particle hydrophobicity and flotation cell turbulence) For composite particles (the bubble may attach to good hydrophobic region, but the expansion of the three phase line of contact is limited. Hence, the equilibrium contact angle, characteristic of the hydrophobic region, may never be attained, and the force of attachment is decreased relative to that possible for homogenous hydrophobic surfaces.

May 1, 2013

By Niraj Bala

Boiler tubes of coal-fired boilers suffer severe erosion-corrosion (E-C). One method to counteract this problem is by the use of therma, spray protective coatings. Cold spray coating process was used to deposit Ni-20Cr powder on SA 516 (Grade 70) boiler steel. The bare as wel, as the coated steels were subjected to cyclic experimenta, studies, in the superheater zone of a coa, fired boiler. The weight change technique was used to establish kinetics of the erosion-corrosion. XRD, FE-SEM/EDS and X-ray mapping techniques were used to analyse the as-sprayed and corroded specimens.

Jan 1, 2010

By H. Soltanzadeh

This paper summarizes semi-analytical and closed-form solutions that can be used to assess the poroelastic stress changes induced within a porous formation (reservoir) during a pore pressure change. Further, solutions are presented for the stress discontinuities at the interfaces between reservoirs and the rocks that surround them. When used in combination with rock failure criteria, these solutions enable relatively simple analyses of the potential for induced fracturing or fault reactivation within a reservoir or the rock immediately adjacent to it. The latter, in particular, is useful for assessing if the hydraulic integrity of the surrounding rock (i.e., the bounding seal) will be affected by a pore pressure change. The use of the approach presented in this paper is illustrated with an analysis of a pinnacle reef with dimensions and properties representative of reefs in the Zama oil field, northwestern Alberta, Canada. Scenarios of pore pressure decrease (during historical production operations) and pore pressure increase (during several years of acid gas injection operations) are analyzed, for three different idealizations of reservoir properties and geometry (two plane strain and one axisymmetric). These results suggest that that the potential for induced fracturing is not significant at any point within the reservoir or the surrounding rock for both the production and injection scenarios that were simulated. Similarly, fault reactivation was not predicted for the reservoir or any of the points that were analyzed in the surrounding rock. However, fault orientations having the greatest potential for reactivating during historical production operations were identified; thus, illustrating a means of using geomechanical models to focus geological characterization efforts on the features that are most critical to acid gas containment.

May 1, 2009

By Vincent Jourdain

Located in the James Bay Territory of Quebec (figure 1), the Clearwater property is jointly owned by SOQUEM Inc. and Eastmain Resources Inc. Exploration on the property since the early 70's has resulted in the discovery of several gold showings. Exploration work by the joint venture since 1995 has led to the definition of the Eau Claire Zone containing an indicated resource of 540 000 tonnes grading 11.1 g/t Au (8.7 g/t Au cut at 34.28 g/t Au). Hosted by the archean Eastmain Greenstone Belt, the property geology is dominated by mafic volcanics containing thin horizons of felsic volcanics and/or sedimentary rocks (figure 2). The sequence is metamorphosed to the amphibolite facies and contains two small toalitic intrusions. Regionally, the structural trend is oriented E-W but in the area of the Eau Claire Zone a second trend oriented NE-SW is also present. The first exploration work on the property was conducted by SEREM and SDBJ from 1973 to 1976. It consisted of an airborne electromagnetic survey and a ground follow-up program on several grids. This program, comprising geological mapping, geophysics and drilling, led to the discovery of the Natel showing where a drill intersection returned 8.89 g/t Au over 2.65 m. From 1978 to 1985 the area was withdrawn from staking because of the hydroelectric projects of the James Bay. In 1985, Westmin Resources Limited and Eastmain Resources began an exploration program based on a helicopterborne electromagnetic survey. Once again, a ground follow-up program was conducted on several grids. This program included a soil geochemical survey that identified a strong (up to 10 g/t) gold anomaly. Drilling of the anomaly led to the discovery of the Eau Claire Zone where resources were estimated at 270 000 tonnes grading 6.1 g/t Au at the end of 1990. In 1995, SOQUEM Inc. took an option to gain a 50% interest on the property and obtained its interest in 1998. Since 1995, two principal mineralization zones were identified on the property. The "Rosemary Zone" consists of veinlets and disseminations of pyrite and chalcopyrite within a magnetite-rich amphibolite. The mineralized zone was identified by stripping within an area of 1000 by 500 metres. Drilling indicates copper grades up to 0.32 % Cu over 49.2 m. with locally grades of 0.75 % Cu over 5.9 m. The mineralised zone is associated with QFP dykes and corresponds to a strong magnetic anomaly and a strong copper and molybdenum soil anomaly. The "Eau Claire Zone" consists principally of a set of gold bearing quartz-tourmaline veins oriented E-W and dipping at 45-50??to the south (figure 3). More than ten different veins are recognised in the zone and up to eight veins were observed in a single trench (figure 4). The host rock between the veins shows a degree of deformation similar to the regional volcanosedimentary rocks. Each vein is hosted by a unit of actinolite-tourmaline-biotite schist up to one meter thick. The veins and their hosting schist clearly cross-cut the schistosity of the hosting lithologies and the contacts between amphibolites and felsic to intermediate rocks. Usually, the veins are less than a meter thick and are composed of quartz, tourmaline and calcite. The proportion of quartz and tourmaline varies from 0 to 80% within a single vein. The veins commonly show massive, banded or brecciated texture. Sulphides, mainly pyrite, pyrrhotite and chalcopyrite, generally form less than 5% of the vein material.

May 1, 2001

Purpose of TSUG Continuous Improvement in Mining Share Best Practises Exchange Ideas Network for Frontline Supervisors and Middle Management Meetings ? Two per Year -Spring and Fall ? Thirty Five to Forty Attendees ? Rotate Between Host Properties ? Host Mine Provides ? Meeting Room for One Day Tour of Mine and Maintenance facilities on Second Day

May 1, 2010

By F. Chiesa, Jeremy Carignan, B. Duchesne, D. Levasseur

"Aluminium A206 (AlCu4) is one of the strongest aluminium casting alloys with tensile properties approaching those of ferritic ductile iron. If the specification on the silicon content (< 0.05%) is easy to achieve during alloy ingot production, it is not the case in a foundry, where returns are used which are not perfectly cleaned from the silicate containing molding sand (Olivine). In alloy A206, the Si content is controlled in order to avoid the formation of a low melting point intermetallic phase (such as phase Q Al5Cu2Si6Mg2); these phases will melt during the solutionizing heat treatment to which alloy A206 must be subjected to develop its outstanding mechanical properties. This incipient melting may deteriorate the mechanical properties of Alloy A206 if the solutionizing treatment is applied at the standard temperature of 530°C.In the present study, a lower temperature solutionizing (520°C) was applied to a high Si content 206 alloy in order to reduce or eliminate the possible incipient melting. This was carried out on a complex shape industrial casting weighing 14 kg (31 lb) and 560x410x250 mm (22x16x10”) in size poured in aluminum 206 with a high silicon content (0.22% vs 0.05% max for alloy A206). Twenty ASTM E8 subsize tensile specimens were excised from two locations in the casting in order to compare the tensile properties for the two solutionizing temperature used (530 and 520°C). Optical and SEM microscopy allowed to investigate the causes of the differences in the properties observed between the 2 zones of the casting studied for 3 different heat treatments. INTRODUCTIONIn spite of their “textbook” outstanding mechanical properties (Up to twice the strength and elongation of the widely used A356 alloy), aluminum-copper alloys of the 2xx series are seldom used because of their propensity for hot tearing [Li, 2011], the segregation of copper [Cho, 2003], and their sensitivity to stress corrosion cracking [Jean, 2009, p. 113)]. Also, because of their wide freezing range and high thermal conductivity, a wide mushy zone makes feeding difficult, unless strong temperature gradients are created by liberal use of chills and risers in the critical zones of the part. Because they are prone to hot tearing, grain refining of Al-Cu alloys is particularly important, titanium playing a major role in the process [Sigworth, 2003]; grain refining has also been shown to be beneficial to fatigue strength [Jean, 2009, p. 103]. The practical basis of foundry practices pertaining to these alloys is outlined in an AFS webinar [Weiss, 2014]."

Jan 1, 2016

By M. Celikin, M. Isac, R. I. L. Guthrie, S. Ge

Horizontal Single Belt Casting (HSBC) is a near-net-shape casting process in which molten metal is directly cast into thin strips, at high cooling rates (order of several 100°C/s), with the potential for high volume, friction-free, continuous production of metal strips. This casting process was used in the present work to produce strips of Al-Mg alloys in the AA5000 series, with additions of Sc and Zr. Such aluminum alloys show exceptional potential as a structural material for transportation/aerospace applications. To demonstrate the suitability of the HSBC process to manufacture competitive strip products of Al-Mg-Sc-Zr, the mechanical properties and microstructures of the strips produced using the HSBC process were compared with conventionally cast products. The effects of annealing on the mechanical properties of the strip-cast Al-Mg-Sc-Zr alloys were also investigated.

Jan 1, 2014

By R. Vergunst, E. A. Devuyst, G. Robbins

"INTRODUCTIONThe Inca process for continuous cyanide removal from industrial wastewaters was patented in 1984 by G.J. Borbely, et.al. (1). The process requires SO2, air, lime and a copper catalyst. Both free and complexed cyanide are oxidized to cyanate in the pH range 8 to 10. Cyanide bound to iron is removed by precipitation as a ferrocyanide insoluble salt and other base metals are removed as hydroxides.The process was piloted in 1982 on barren bleed solution at Campbell Red Lake Mines Ltd., Ontario (2). Since 1982, the Inca SO2-air cyanide removal technology has been applied in twelve commercial installations. The process has significant advantages over other commercial processes in the completeness of cyanide removal and lower reagent requirements and costs.COMMERCIAL INSTALLATIONSBy the end of 1988 Inca will have applied its patented cyanide removal technology to twelve commercial operations. Three of these, namely Scottie Gold Mines, Dupont of Canada Expl. Baker mill and Carolin, all in British Columbia, Canada, have ceased cyanidation operations but SO2-air cyanide destruction results were good for all mills, particularly so for over two years for the Scottie mill.Removal of cyanide from CIL slurry tailings is applied at Equity Silver (9,500 tpd) and Inca's new 1,200 tpd mill at Inca/Golden Knight. Detoxification of CIP tailings is carried out by Colosseum California (3,600 tpd) and Canamax's Ketza River operation (360 tpd). Repulped tailings from Merril-Crowe flowsheets are treated at Total Erickson's Mount Skukum mill (300 tpd) and Skyline's Johnny Mountain mill (200 tpd) and barren bleed at Inco/Queenston's McBean mill (500 tpd). Lynngold's MacLellan mill (1,800 tpd) treats pond supernatant water. Plating shop cyanide effluents are decyanized at Kuntz Electroplating in Kitchener, Ontario. Many of the above commercial operations were described in some detail in previous publications (3,4). Typical installations are described in this paper. A summary of operating results is given in Table 1."

Jan 1, 1989

By Lucas van Latum

A Model for Safety Swiss cheese metaphor of safety layers Image »Multiple layers with independent, often transient failure modes »For a loss to occur, all layers must fail independently and simultaneously ??Latent? failures are due to inherent system flaws ??Active? failures are due to unsafe acts

May 1, 2011

By W. G. Jewitt

THE Box mine, situated in Saskatchewan on the north shore of lake Athabasca, is unique in two respects. It is the first and, so far, the only gold mine in Saskatchewan, and it is the only gold mine in Canada to employ a large-scale forced caving system as the main mining method. Discovered in 1934 by Tom Box, an Edmonton prospector, its subsequent history, while breaking no records for speed, has been one of steady and more or less normal development. Camp and plant are situated close to the shore of Beaverlodge bay, sorne 50 miles east of the Saskatchewan-Alberta boundary and 35 miles south of the north boundary of the Province. The railhead at Waterways, Alberta, is about 220 miles to the southwest. Prince Albert lies some 450 miles to the south. The surrounding country presents a rather rugged variation of the usual Precambrian topography, with hills rising five to six hundred feet above lake Athabasca. The numerous lakes and islands, together with the wide expanse of lake Athabasca, compose an attractive scene, at least in the not over-long &apos;open water&apos; season. The winters are long but not extremely cold, judged by prairie standards. The small lakes break-up around May 20th and the &apos;freeze-up&apos; stops navigation early in October. Though apparently remote, the Box mine is fortunate in having reason-ably cheap transportation from Edmonton. The 300-mile railway from Edmonton to Waterways is the most expensive section, the rate for 1st class freight being $1.70 per hundred pounds and for 5th class freight $0.77 per hundred. Freight from Waterways to the mine, approximately 140 miles down the Athabasca river and 90 miles along lake Athabasca, is delivered by barges and tugs for 50 cents per hundred pounds. All freight is delivered during the &apos;open water&apos; shipping season, which lasts from about .Tune 7th to October 7th. In normal years, barges are loaded to 3 to 3 1/2feet draught up to September 1st. After that date, and earlier in dry years, shallow water at Waterways reduces the barge loads. Barges of 100 to 200 tons capacity handle all mining freight, including pieces up to 15 tons in weight, without undue difficulty.

Jan 1, 1940

By W. F. Harkness, D. Hodgkinson

"A non-destructive testing program was established at Crows Nest Resources (C.N.R.), Line Creek mining operation following an in-service fatigue failure of a front wheel spindle on a large haulage truck.This failure identified a definite need for improvements in the ultrasonic techniques used during the mandatory spindle integrity examinations. Initial investigations using common mining industry ultrasonic examination techniques showed that the smallest detectable cracks were 75 mm in length for the spindle types in service at the C.N.R. site. The Initial findings indicated that inadequate inspection technique design was the cause of the poor performance. To improve inspection reliability it was identified that improved ultrasonic techniques were required. Results using designed ultrasonic techniques were encouraging, with the detection of simulated and natural cracks 12 mm long achieved. The cost benefits associated with the extended spindle life, following the removal of these small fatigue cracks, far exceeded those of the expertise and effort necessary to implement and conduct the N.D.T. program.Introduction During 50 years of evolution, non-destructive testing (N.D. T.) has progressed from a laboratory curiosity to a well accepted and invaluable tool used in the assessment of material integrity. Unlike destructive testing, N.D.T. does not deform or render the material useless. Non-destructive tests may involve many applications, from the determination of a corrosion prevention coating thickness to the examination of a raw material for internal and external deformities.Within the mining sector, highly-stressed components will normally have been subjected to some form of non-destructive test during their manufacturing cycle. These tests are used to ensure the component does not contain material flaws whichmay be detrimental to its service performance.While the component may have assured quality when produced, deterioration by fatigue may occur during an aggressive service life. Large dynamically-loaded components such as haulage truck front wheel spindles are , in particular, prone to this service related problem."

Jan 1, 1987

By Stephen C. Tadolini

"The use of a torque wrench to establish the amount of actual load developed on an expansion anchor bofting system dates back to work completed in the early 1950s. The advent of ultrasonic measurement systems and hydraulic torque wrenches has made it possible for the U.S. Bureau of Mines to perform torque-tension measurements in the laboratory and the field much more accurately. The results indicate that the amount of initial boft preload may be overestimated by amounts in excess of 45% of the expected load using torque wrenches. This inaccuracy is primarily due to the friction that occurs between the bearing plate and the head of the boft. These parameters become extremely important when the support system is being used to prevent joint members from slipping relative to each other or when the boft acts as a heavy spring to clamp two or more sections together. Methods to overcome the frictional losses are presented in conjunction with a laboratory method to determine the actual torque-tension ratios for expansion anchor and combination bolting systems.IntroductionMechanically anchored roof bolts have been widely used in the mining industry since their introduction in 1947. Estimates made in 1989 indicate that out of 85 million fixtures, approximately 49 million bolting fixtures still use applied tension to complete the reinforcement necessary to maintain stable openings. Nearly 85 million bolts are used yearly. The most widely used bolt is the resin-anchored headed rebar, followed by standard mechanical roof bolts, specialty bolts (mechanically anchored, resin enhanced fixtures) , and combination bolts . Po st-tensioned resin rebars, combination systems, and friction stabilizers make up the remaining 10% of the units used (Fig. I).For mechanical, combination, and tension rebar bolts, the bolt tension is the primary means of reinforcing the roof, but in many cases, because of poor installation procedures, the bolts are ineffective. Mine operators recognize the importance of proper installation procedures. Long-term bolt tension measurements are required in the Code of Federal Regulations (CFR)In each bolting cycle, the actual torque or tension of the first tensioned bolt installed with each drill head shall be measured immediately after it is installed. Thereafter, for each drill head used, at least one roof bolt out of every four installed shall be measured for actual torque or tension. If the actual torque or tension of any roof bolts measured is not within the range specified in the roof control plan, corrective action shall be taken."

Jan 1, 1991

By M. Sommerfeld, U. Schwarz-Schampera, B. Friedrich, D. Friedmann

The steadily growing demand for metals and their price increase at metal exchanges make the mining and utilization of marine mineral resources like polymetallic nodules, manganese crusts or sulfide deposits in the near future a viable option to potentially increase the supply of base and precious metals. For a country with low potential to mine land-based resources like Germany, the industrial recovery of metals from marine mineral resources could lead to a decreased dependency on imports. In this study, seafloor massive sulfides from the German license area in the Indian Ocean (Kairei field, Southern Central Indian Ridge) are treated to recover copper and precious metals. The aim of the project is to demonstrate the transferability of existing metallurgical techniques to the raw material of deep-sea massive sulfides. As a starting point to process this unconventional resource, samples from the Indian Ocean are chemically analyzed and mineralogical characterized. A comparison is carried out between the samples and land-based copper resources, to highlight the potential which lies in mining the deep-sea floor. This paper will show the general possibility of applying a two-stage pyrometallurgical process, based on a concentrate smelting operation, followed by a converting operation in lab-scale to the provided samples of massive sulfides. Generated slag from the concentrate smelting and the converting operation are investigated by X-ray diffraction to determine the mineralogical composition. The two-stage pyrometallurgical process is investigated by the thermochemical modelling tool FactSageTM 7.2 to evaluate the phase distribution of relevant elements between the metal, matte, slag and gas phase. The thermochemical boundaries of the pyrometallurgical process are therefore set and the results of the thermochemical study can be used as an indicator for the efficiency of an up-scaled process and the generated amount of side-streams, which need to be further treated or circulated back into the process. INTRODUCTION Seafloor massive sulfides (SMS) are the third kind of discovered deep-sea minerals besides ferromanganese nodules and cobalt-rich ferromanganese crusts (Sharma, 2017). They occur in water depths around 250–4,000 m (Koschinsky et al., 2018). SMS are characterized by a high base metal and sulfide content. They were created by fluid circulation and hydrothermal convection over time (Han et al., 2018). Commonly, areas rich in SMS are associated with hydrothermal vent fields on the seafloor (Keith et al., 2018).

Jan 1, 2019

By S. F. Guo, B. W. Zheng, X. L. Huang, S. W. Qi

"The study of mechanical characteristics of rock discontinuities under different shear deformation velocities is an important premise of rock slope dynamic response analysis. According to disposing and calculating the experimental results of previous research about peak shear strength of rock discontinuities under different shear deformation velocity of constant normal loading, the law of influence of shear velocity on the total friction angle is studied. Based on the research results, it can be found that the total friction angle of rock joint specimens varies in the form of negative logarithm with the variation of shear deformation velocity. It’s also indicated that the total friction angle of rock joints decreases with the increase of shear deformation velocity for rock joints of relative strong homogeneity and isotropy. However, the total friction angle of rock joints increases with the increase of shear deformation velocity for rock joints of relative strong heterogeneity and anisotropy and the latter amplitude of increase is less than the former amplitude of decrease. The physical property and microscopic geometry of rock joints play an important effect on the increase or decrease tendency and amplitude variation of total friction angle with the increase of shear deformation velocity.INTRODUCTIONThe rock slope dynamic response is largely restricted by rock discontinuities. Hence the study of dynamic characteristics of rock discontinuities, especially the dynamic shear characteristics is an important premise of rock slope dynamic response analysis (Qi et al., 2007). Seismic load is both dynamic load and cyclic load (Liu et al., 2011). Under the dynamic and cyclic shearing actions of seismic load, the rock slope which is stable under the condition of static load may slide along the rock discontinuities whose shear strength reduce and then the earthquake landslides occur. The strength degradation and deformation mechanism of rock discontinuities under the dynamic and cyclic shearing actions is one of the key problems to be solved in the work of earthquake prevention and control of engineering slope. Based on the above understanding, predecessors conduct some researches which focus on the shear behavior mechanical characteristics of rock joints under cyclic shearing actions (Plesha, 1987; Hutson & Dowding, 1990; Jing et al., 1992, 1993; Huang et al., 1993; Qiu et al., 1993; Homand et al., 2001; Lee et al., 2001; Jafari et al., 2003; Liu et al., 2011, 2013). However, there are a few researches about the mechanical characteristics of rock joints under different shear deformation velocities because of the restriction of shear apparatus. Crawford and Curran (1981) conducted a series of one-way cyclic direct shear tests on four kinds of natural rock joints under different shear deformation velocities varying from 0 to 200 mm/s. The tests showed that at low normal stresses the peak shear strength of soft rock joints exhibited an increase up to a certain velocity, after which it remained essentially constant. For rock joints of intermediate hardness, the peak shear strength was essentially independent of shear deformation velocity; whereas for hard rock joints, the peak shear strength of which showed a significant variation with the shear deformation velocity. Jafari et al. (2003) carried out a series of conventional triaxial tests on artificial rock joints of regular saw-tooth shape with axial loading rate from 0.05 mm/s to 0.4 mm/s."

Jan 1, 2015

By Michel Ruel

Most plants do not track how their systems perform. Optimization is the easiest way to benefit from your control systems. We suggest an approach in four phases. The first phase is to assess all equipment to determine the performances for instruments, valves, variable speed drives, and other equipment. The second phase is to remediate instrumentation problems, including the ones pertaining to valves, variable speed drives, analyzers, transmitters. When equipment is in order, loops are put back in automatic mode. If a loop oscillates, use standard default values for this type of loop. The third phase consists in validating the control strategies, properly configuring the systems (control system, programs and parameters, HMI, alarms), and then tuning the loops and control strategies. The fourth phase consists in analyzing the process and expected performances in order to optimize the control loops and control strategies. If performance is not sufficient, a decision tree will be presented to determine the right approach: advanced regulatory control, model predictive control, or fuzzy logic control. Once all steps have been completed, control performance monitoring software is used to sustain the results and pinpoint equipment or loops not performing as stated. Alarm management and rationalization could also be performed after auditing the alarm system, if needed. Examples from plants will be used to demonstrate how this step-by-step method is applied and produces results. INTRODUCTION Maximizing what you already have is the best investment to remain competitive. This article aims to show the benefits of a systematic approach using modern tools to improve plant performance. We at BBA suggest dividing the work in four phases, and a subsequent phase can begin when the previous one has progressed: Assess, Remediate, Stabilize, Optimize, or add advanced control. This approach has been successfully applied to several sites. Examples and illustrations from these plants demonstrate how this step-by-step method is applied and produces results. Under the BBA method, there are four questions to answer before proceeding to the next step. For each control strategy, you should ask the following questions: Assessment: Does it work? Remediation: Do you use it? Stabilization: Is it stable? Optimization: Does it perform? Do you need advanced control?

Jan 1, 2019

By J. F. J. Thomas

"AbstractBoth the quantity and quality of waters available as raw materials are important to Canadian industry and to the national economy. The huge demands of many Canadian industries is illustrated by tabulated figures, based on the 1950 Canadian production of certain products, and on United States figures for the gallons of water required to produce a unit quantity of each product. It is suggested from comparison with American survey results and figures that Canadian industrial water consumption is 1 to 11/2 billion Imperial gallons per day. Since present information on Canadian usage is meagre and it is not certain that American survey results can be directly applied to Canadian industry, this estimate must await confirmation in future studies.The hydrologic cycle and the principal factors affecting the quantity and quality of water, namely, climate and season, topography, geology, vegetation, and human activities, are discussed and the principal salts dissolved in water which affect industrial use are enumerated.The present survey studies by the Mines Branch on water quality are outlined. Besides chemical analyses of municipal water supplies within a watershed, periodic sampling and analyses of major surface waters for a one-year period is being carried out. The importance of studies on seasonal variation in quality is stressed by comparing the dissolved salts in various river waters with river flow. Figures showing such relationships in the Rideau river and Ottawa river at Ottawa, the Columbia river at Trail, B.C., and the Battle river at Unwin, Sask., are presented. Different rivers show different quality changes with changing flow, and possibly only after long-term studies can the relationships be predicted.Quality studies on water may be as important as studies on many other raw materials. The quantity of the raw material, water, is not inexhaustible nor is the quality indestructible, and more realization of its importance, followed by conservation and intelligent use, is desirable."

Jan 1, 1952

By T. Güyagüler, U. Y. Önder

"This study investigated the psychrometric properties of ventilating air in GAL coal mines. Related measurements were done in underground openings and have been arranged as input data for computer programs prepared for ventilation network and psychrometric analysis.Results obtained from network analysis have been used for psychrometric analysis of ventilating air. Changes in heat and moisture content of air in two major path s between entry and discharge of ventilating air have been investigated. Psychrometric processes occurring in the mine were determined and are shown graphically in Figures 1 and 2. Special attention has been given to determine the changes in psychrometric properties and processes involved in the faces. Results are outlined in this paper.IntroductionThe psychrometric properties of mine air are important factors to mine productivity and efficiency. Therefore, psychrometric analysis should be made for all underground mines; any undesired situation observe d could be corrected by taking the necessary precautions.The analyses were done as a case study for GAL mines, the only mechanized lignite coal mine in Turkey. In this mine, workable reserve is about 300 million tons of coal and yearly planned production is 2.2 million tons. Production is continuing from a coal measure-bed having two coal seams with average thicknesses of 1.52 m and 1.72 m respectively. A 0.85 m shale band exists between these two seams.Two full y-mechanized faces, approximately 220 m long, usually work simultaneously. All measurements, including mine gases and air velocity, are done by sensors connected to a control room by a monitoring system.In the analysis, a line diagram is utilized to described the mine on which every junction and branch is numbered."

Jan 1, 1992