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Much interesting data on cemented carbides has been published over a period of years which, when classified and pieced together, gives a clear picture of this special branch of powder metallurgy. This is an attempt to present the essential information in an ordered account.THE HARD CARBIDES-THEIR PROPERTIES AND PREPARATIONThe so-called hard or refractory carbides are the carbides of a number of metals which are grouped together in the Periodic Classification. These metals are in groups IV, V and VI. They are titanium, vanadium, chromium, zirconium, niobium (columbium), molybdenum, hafnium, tantalum and tungsten. These carbides have attracted the attention of chemists because of their remarkable properties. They possess very high melting points, and are rather difficult to prepare in the pure state. Their outstanding propertyis their extreme hardness, which they share with certain other carbides, such as those of silicon and boron. In addition, these compounds possess distinctly metallic properties, such as lustre (in fused specimens) and high thermal conductivities.(l)t They are capable of forming alloys in two ways:1. With metals, particularly those of the iron group. 2. With each other (a case of solid solubility).The constitution of these substances is not that of ordinary salts, which obey the usual valency rules, but must be likened to that of certain intermetallic compounds. Actually they are "interstitial" compounds(2), that is, they are formed from the ordinary metallic lattice by the insertion of the relatively small carbon atoms in the interstices.. The energy required to fill the lattice completely is high, and this explains the difficulty often found in obtaining the exact stoicheiometric compound. Thus the carbides can have a range of composition, and can be considered as solutions of carbon in the respective metals.Physical Properties of the CarbidesThe hardness of these compounds is so great that it is difficult to compare the individual compounds on this basis. Becker(l) gives values on Moh's scale, which are not very accurate and are of no great value. Burden(3) has reproduced a diagram by Hatfield which indicates that the cemented carbides are between 1,400 and 2,000 on the Vickers diamond scale. However, the pure carbides are harder, tungsten carbide being about 2,200. Hoyt(4) describes a method of measuring hardness applicable to powdered specimenswhereby the powder is rubbed on a standard block of cemented tungsten carbide under standard conditions, and the rate of wear is determined. In...

Jan 1, 1942

By D. F. Malan

This paper presents an overview of work conducted over several years to investigate the continuous stope closure profiles recorded in tabular excavations and the use of this data as a hazard indicator. In spite of the brittle nature of the rock, measurements in gold mines and intermediate depth platinum mines revealed a significant time-dependent closure component. Various approaches to simulate the time-dependent closure have been investigated. Viscoelastic theory is able to simulate the time-dependent closure behaviour, but there are subtle problems with the use of this theory as it cannot simulate the failure processes in the rock. To overcome these problems, continuum and discontinuum elasto-viscoplastic models were developed by the authors. Discontinuum models have the advantage of being able to simulate the creep behaviour of prominent discontinuities. Development of these models has led to useful insights into rock mass deformation and has made the numerical simulation of parameters, such as rate of mining, possible for the first time. A number of practical applications for the mining industry have been developed from this study. Among these are the delineation of geotechnical areas using closure data, use of the data as a hazard indicator and to give warning of large collapses in the platinum mines, identification of areas to be preconditioned in the gold mines, measurement of the effectiveness of preconditioning and improved da

Jan 1, 2007

By Arthur D. Silber

The economic success and growth of any metropolitan region depends on mobility. Today, mobility between New Jersey and New York is threatened by a transportation system that cannot meet 21st century travel demands. The transportation bottleneck created by the Hudson River threatens the viability of one of the world?s great centers of commerce and culture. Fortunately, there is a solution: The Access to the Region?s Core Mass Transit Tunnel. The US$8.7-billion Mass Tran-sit Tunnel?s (MTT) new two-track line will double commuter rail capacity under the Hudson and create a new, state-of-the-art cavern station in Midtown Manhattan, with wide platforms, high-speed escalators and other features to improve riders? travel experience. The capacity and other benefits of the MTT project will launch a new era of prosperity for the region, just as the Pennsylvania Railroad did almost 100 years ago when it built the existing two, single-track rail tunnels that now form the sole commuter rail link between New Jersey and New York. The existing tunnels run from North Bergen, NJ, under the Hudson River to Pennsylvania Station at 33rd Street in Manhattan. Construction on the MTT, the largest public works project in the United States, is scheduled to start this year and continue through 2017. The MTT is ready to go to construction thanks to a major commitment of financial, engineering, project management and other resources from NJ TRAN-SIT, New Jersey?s statewide mass transit agency, and the Port Authority of New York and New Jersey, a bistate agency that operates the Holland and Lincoln tunnels, the George Washington Bridge and other major transportation facilities in New York and New Jersey. The project is also strongly supported by the state governments of New York and New Jersey, as well as that of New York City. The MTT is New Jersey Governor Jon Corzine?s number one transportation priority.

Jan 1, 2009

By Hargraves A. J, Smith J. W

Experiments conducted at Tahmoor Colliery, Sydney Basin, have demonstrated the variability in chemical and isotopic composition of seam gases issuing from boreholes in the Bulli seam and desorbing from lump coal from the same source.From this work it appears that an immediate preferential release of methane accompanies the physical disturbance of the coal seam by penetration with development or drilling or by detachment. In addition, both early released methane and carbon dioxide are depleted in 13C relative to later desorbed gases, therefore the analyses of gas samples taken after such events may not reflect the true bulk composition of the undisturbed seam gas in situ. A method for overcoming this problem by taking gas samples at depth in the "steady state" is proposed.

Jan 1, 1987

By A. C. Smith

Although only used in a few U.S. longwall mines, bleeder-less ventilation systems can be an effective spontaneous combustion control method in mines having a demonstrated history of spontaneous combustion. To provide insights for the optimization of bleederless ventilation systems for U.S. underground coal mines, a computational fluid dynamics (CFD) study was conducted to model the spontaneous heating in longwall gob areas using a bleederless ventilation system. A single longwall panel with a bleederless ventilation system was simulated, and typical longwall mine ventilation data were used in the simulations. The permeability and porosity profiles for the longwall gob were estimated using a geotechnical model and were used as inputs for the CFD modeling. The effects of gob permeability and resistance of the collapsed entries on the spontaneous heating were studied. The effectiveness of using nitrogen injection to prevent spontaneous heating in the gob was also examined.1

Jan 1, 2008

By John Lindsay

"Although diamond mining is a relative newcomer to the Canadian mining industry, with the first diamond mine coming on stream in 1998, Canada is already a significant producer of high quality diamonds. This paper will review diamond production trends and highlight some of the projects currently under development, which have the potential to enhance Canada’s role as a significant diamond producer.Diamond recovery plants generally incorporate well-established mineral processing and recovery techniques, with issues such as product security, cut-off sizes, and diamond preservation becoming important considerations when developing process flowsheets. A diamond processing plant must achieve three key objectives, namely:• Liberation of the diamonds from the host rock;• Separation of the heavy minerals, which include the diamonds, from the host rock;• Recovery of the diamonds from the heavy mineral concentrates.Processing technologies and equipment commonly utilized in diamond processing plants will be reviewed and some of the significant issues associated with each option briefly discussed.Typical process flowsheets will be presented.Finally, an overview of De Beers’ Victor diamond project, located in northern Ontario, will be provided. This potentially significant diamond producer is currently at a pre-feasibility stage of development.DIAMONDS IN CANADAWorld Diamond ProductionCommercial diamond mining commenced in earnest with the discovery of the Kimberley diamondfields in South Africa in the late 1800s, and this resulted in a dramatic increase in the supply of diamonds. As can be seen from figure 1, world diamond production, mainly from South Africa, Angola, Congo, and Namibia, remained relatively constant through the early 1900s until the development of the large Russian kimberlite pipes in the 1950s. Production increased again in the 1960s and 70s with the development of the Botswana mines, but the most significant increase in global production came from the Argyle mine in Australia, which came on stream in 1983 and produced a peak of almost 43 million carats in 1994, representing approximately 40% of the world market. Production from Argyle has since fallen-off as grades have declined and the strip ratio has increased with the deepening of the open pit."

Jan 1, 2003

By George Anagnostou

Time-dependent ground behavior may have important implications for the construction process or the life of a tunnel. The paper gives a concise overview of the influence of time on the deformations and the stability of underground openings, including topics such as face stability in soft ground or the time-development of pressure or deformations in squeezing or swelling rock. While keeping in mind practical questions of tunnel engineering, emphasis is placed on understanding the observed time-dependency, on the underlying mechanisms (such as pore water pressure dissipation or chemical processes) as well as on the respective inherent prediction-uncertainties and design-uncertainties.

Jan 1, 2007

By C. Fairhurst

Most of the papers designated as being within the topic of underground storage at this Symposium are concerned with aspects of radioactive waste isolation. Although this is, unquestionably, an important international application of underground storage, and one involving a considerable number of research investigations, the subject of underground storage is indeed much broader. Several major international conferences have been devoted exclusively to it. Applications include storage, under a range of temperatures and pressures, of oil and liquefied petroleum products, compressed air, heat, foodstuffs of various kinds, hazardous and 'nuisance' industrial by-products, and a variety of special applications, both civilian and military - some in use, others proposed. Storage may be in caverns excavated specifically for the purpose, exhausted mines may be adapted for storage or, in some cases, the material to be stored may be injected under pressure into the pore spaces of porous-permeable formations at depth. A variety of rock types and geological environments are used, e.g. excavations in salted or domal salt, where long-term creep closure of the openings is a concern; massive granite, where fluid loss through fissures may be important. Cavities may have spans of several tens of meters, and there is interest in achieving still larger excavations. As would be expected, this breadth of underground storage applications introduces a similarly broad range of questions in rock mechanics and rock engineering. The report will review these questions and recent developments in rock mechanics research, computational procedures, and design applications - and will also discuss the opportunities for a still greater range of applications of underground storage to current industrial and social problems.

Jan 1, 1989

By Thomas Z. Jones

Deep mining within the Sewell Coal member of the New River Formation in southern West Virginia has exposed several small-scale thrust faults and related features. The faults were en- countered in Westmoreland Coal Company's Eccles No. 6 Mine located near Beckley, West Virginia (Figure 1). The purpose of this paper is to: 1) describe the nature of these faults and the effect they have on mining, 2) discuss the roof support methods used in the fault zones, 3) establish a mechanism for the origin of the faults. and 4) demonstrate how the mechanism was used to forecast fault trends across the mine property.

Jan 1, 1986

By Robert B. Johnson

The refraction seismic method has been used as an indirect means of exploring for fluorspar in southern Illinois by the Illinois State Geological Survey. Use of the method has been restricted to those areas where mineralization is associated with faults, a restriction necessitated by the operating principles of the refraction method. The seismic data enable the interpreter to locate fault zones in the subsurface and, under ideal circumstances, to make estimates of dip direction and magnitude and vertical displacement provided the local stratigraphic units are known and are geophysically recognizable. In this instance, refraction seismic exploration has been successful in the surface mapping of well-developed faults, both simple and complex with which fluorspar may or may not be associated. However, less clear results have been obtained where faulting has been less severe and where there are numerous accompanying mineralized joints.

Jan 1, 1964

By Mark Rybak

On August, 31, 2006, Tropical Storm Ernesto hit the City of Richmond, Virginia. The Battery Park area was hit particularly hard, as flooding forced an evacuation of the area. A large sinkhole collapsed a sewer line in the Battery Park area, blocking the pipe and causing more serious flooding. This case history describes the fast track design, bidding, and construction of an emergency tunnel to bypass the collapsed sewer. Innovative value engineering, tunneling and shaft sinking methods, and final lining design all contributed to the success of this project. The storm inundated Richmond, Virginia with up to twelve inches of rain in some areas causing widespread flooding and damage. One of the hardest hit areas of Richmond was Battery Park. A major trunk sewer in the Battery Park area collapsed causing local combined sewer and storm-water flooding. The collapsed sewer was an 8'-3" wide by 9'-6" high arch sewer that was constructed in the nineteen twenties and later filled over with municipal solid waste and a soil fill cap to current elevations. A sinkhole was created in the area of collapse approximately sixty feet deep and one hundred feet in diameter causing the existing arch sewer to become blocked. As a result of this blockage contaminated flood waters reached depths in low lying areas in excess of twenty five feet. [ ]

Jan 1, 2008

By R. W. Heins, N. Street

An investigation was made of the Rehbinder-Kuznetsov pendulum as an instrument to aid in the study of rock drillability and of the effect of surface active agents on rock drillability. The "critical weight", i.e., the pendulum weight at greatest sensitivity, was determined for several solids and it was shown that a change in surface environment changed the maximum value of the apparent hardness but not the critical weight, and the critical weight increased with increase of hardness of the solid used. Using silver halides as the solid material, and solutions of either silver nitrate or the appropriate alkali halide, it was shown that there is a hardness maximum at the zero point of charge of the particular silver halide. INTRODUCTION The development of relative hardness measurement by the method of damped oscillations, or what has been called the pendulum sclerometer, is due largely to the Russian workers P. A. Rehbinder and V. D. Kuznetsov and their co-workers.1,2 The apparent simplicity of the method has led to its use in a number of fields, particularly those where relative hardness has to be determined on a brittle solid. As will be shown, the simplicity of the method belies its complexities. THEORY OF THE PENDULUM SCLEROMETER The operation of the pendulum is quite simple. Make a sharp point such as a diamond, hardened steel or tungsten carbide, as the fulcrum of a pendulum, with the center of gravity of the system below the point of support. The attenuation of this pendulum is a function only of air friction, provided no fragmentation, breakage or other work is performed by the point. However, when the solid surface breaks or disintegrates under the point, and the latter penetrates the solid, part of the energy of oscillation is absorbed in the work of creating new surface, and the rate of attenuation increases. In the case of brittle solids, the point of the pendulum produces fragmentary particles, whereas the point produces plastic deformation in a plastic solid; but in both cases damping occurs. This pendulum damping is a function of the hardness or strength of the solid. Whereas a pendulum oscillating on a hard material attenuates primarily by air friction, in the case of a soft material, the points penetrate the surface of the solid, producing new surface, and the pendulum damps much faster. Thus the attenuation rate is a function of the hardness or strength of a material in both plastic and brittle substances. Russian workers initially used a single support for the pendulum, but this created many problems because of oscillation of the pendulum in more than one plane. A revised version used two points, or sometimes a prism as support, successfully confining oscillation to one plane. The version using two points was constructed and used throughout this investigation, making the recording of the attenuation as a function of time relatively easy. That both points should be in contact with the solid during the damping is implied. Rehbinder (c.f. Kuznetsov2) proposed that the hardness H as measured by this method could be expressed by a quantity which is inversely proportional to the relative initial rate of attenuation of amplitude. where H = hardness parameter (arbitrary units) a, = initial amplitude da/dt = rate of attenuation of amplitude with time. In the simplest case of damping with a constant logarithmic decrement, H can be regarded as a constant for the duration of the whole damped oscillation process. That is

Jan 1, 1966

By G. Bonnell, W. Lidkea, M. C. Bétournay, E. Edwardson

"Hydrogen fuel cells are a known technology, having been applied to stationary (e.g equipment, buildings, and power plants) and vehicle applications (e.g transit buses and space shuttles). There is currently a growing need to provide alternate power systems to diesel fuel for underground mining vehicles to improve underground air quality and reduce production costs and greenhouse gas emissions.To date, however, fuel cells have not been exposed to underground mine air and physical conditions. A testing program was carried out to provide information on the vulnerabilities of fuel cells as part of a number of proof-of-concept projects to apply hydrogen power to underground mining vehicles. The fuel cell type of choice for the industry, the proton exchange membrane, would function at the range of temperatures encountered in underground and surface operations, and use hydrogen that is stored under low pressure and risk.A small fuel cell stack was tested in a cooperative project between CANMET, the Fuelcell Propulsion Institute, Inco, the Ontario Ministry of Labour, Sandia National laboratories, and H-Power. This article will review the tests carried out to measure the effects from high humidity, mineral dust, diesel emission gasses and diesel particulate matter, as well as from shock and vibration provided to the unit in underground conditions at Inco’s 175 Orebody minesite and Stobie mine. The test results provided will show that the unit was not affected by the underground conditions; physically and electrically, the unit performed without any reduction in operation or adverse effects imposed."

Jan 1, 2005

By Steve Kral

Amax Coal Industries Inc.'s Delta Mine is a medium-sized. high-sulfur coal producer that has lived up to the challenges posed by nearly six decades of a highly competitive domestic coal market. The mine now faces one of its biggest challenges - the same one staring at the dozens of other high-sulfur producers in the Midwest - the Clean Air Act Amendments of 1990. The 59-year-old mine, located in the coal fields of southern Illinois, has remained one of the state's oldest continuously operating mines by rolling with the ups and downs of the coal market and by incorporating new technologies and innovative productivity improvements into its operation.

Jan 1, 1993

By D. P. Richards

Tunneling in carbonate sedimentary rocks such as lime stones and dolomites can be difficult when solution channels or voids are anticipated. Addressing the risk aspects associated with these formations can be done effectively through the Geotechnical Baseline Report (GBR) by properly characterizing the ground and ensuring that the Owner?s and the Contractor?s interests are represented and protected. This paper presents a review of tunneling difficulties in these rocks and includes a review of site investigations, geologic characterization, and presentation in the GBR. Key construction issues are also discussed, including appropriate excavation technology, mechanisms of face support and groundwater control, and quantifying grout takes.

By Brown A

An experimental evaluation of a selective agglomeration process in which an agglomerated coal rich phase was produced as a result of mixing light oil to various raw coal slurries is described. The beneficiation achieved by this method is compared to that obtained bv conventional froth flotation. The results suggest' that oil agglomeration is a more selective process than froth flotation and is less sensitive to variations in feed pulp density. Selective agglomeration has the additional advantage of producing a low moisture content product. The effect of replacing flotation filter cake with an equivalent amount of selectively agglomerated product in coke-making was studied with the aid of a pilot-scale coke oven. The results suggest that the principal effect of such a measure is to increase the bulk density of the charge.

Jan 1, 1977

By Henry Kreisinger, John Blizard, B. J. CROSS, C. E. Augustine

This report gives the results of 26 tests of a four-pass Edgemoor boiler fired with powdered coal at the Lakeside station of the Milwaukee Electric Railway & Light Co. The tests were made by the fuel section of the Bureau of Mines in cooperation with the research department of the Combustion Engineering Corporation and the operating department of the Milwaukee Electric Railway & Light Co. The object of the tests was to determine the thermal efficiencies and capacities obtainable by burning powdered coal under large central-station boilers, and the possibility of operating such boilers continuously at high efficiency and capacity without destructive effect on the furnaces and without difficulties in refuse removal. In any system for burning pulverized coal the furnace is the most important part because, to justify the cost of pulverizing, the powdered coal must be burned with higher efficiency than coal fired with mechanical stokers. In other words, it is the furnace that by giving higher thermal efficiency must pay for the installation, maintenance, and operation of the pulverizing equipment. No matter how simple the apparatus for the preparation of pulverized coal may be, or how simple the pulverizing process, unless the furnace is so designed that it can be operated continuously with high thermal efficiency, the whole system is a failure. For high thermal efficiency the coal must be burned almost completely with low excess air. But low excess air and complete combustion give high furnace temperature, which in turn causes erosion of the furnace lining and fusion of the ash; and removal of the fused ash is difficult. The necessity of complete combustion with low excess air thus brings with it these two important problems in the design of a furnace for burning powdered coal: 1, Prevention of erosion of the furnace lining; 2, easy removal of refuse from the furnace. For the purpose of solving these problems, the boiler tested was equipped with a furnace having hollow walls, through which about 60 per cent of the air needed for combustion passed before it entered the furnace. By passing through the hollow walls, the air cooled the furnace lining and prevented excessive erosion. A water screen was placed in the furnace about 3 feet above the bottom to keep the refuse deposited at the bottom from fusing and to make its removal easy. The design of the furnace, water screen, and burners was based on the experience gained in the previous cooperative tests1 with a smaller furnace, experimental water screen, and burners at the Oneida Street station of the Milwaukee Electric Railway & Light Co. The boiler tested had 13,057 square feet of heating surface. It was one of eight boilers fired with powdered coal, and was designated as boiler No. 8. The Lakeside station is the largest central station in the world that burns powdered coal exclusively. The coal used in the first five tests came from Illinois. The fuel in the other tests -:vas a mixture of Illinois and Pittsburgh coals.

Jan 1, 1925

Refractory gold ores have been the subject of intensive metallurgical study in order to achieve more efficient recovery of contained values and at the same time to minimise environmental impact. Considerable innovative gold processing technology was introduced in New Zealand last century, the most notable being the first successful commercialisation of the cyanidation process by the Crown Mines Company at Karangahake in 1889. The Karangahake gold-silver deposit was second only +to the Waihi Martha mine in total bullion production from the region with active mining from 1882 until about 1920 and sporadic production between 1930 and 1944. Reevaluation at Karangahake with associated metallurgical testing has continued since that time becoming particularly active in the last decade as a result of increasing gold prices. Gold processing technology is reviewed and results of some recent test work are presented and discussed in the context of Karangahake history and future development possibilities. This work confirms the variability and complexity of the Karangahake deposit both mineralogically and metallurgically and suggests flotation followed by new and innovative smelting is the most appropriate processing route for the recovery of gold from the high grade ore which could be produced from the Karangahake workings in moderate tonnages.

Jan 1, 1993

The method of investigation was to study the distribution of ore in great detail, to make a thorough structural study of the lode and the mine area, and then to compare the results of the two studies. Such a comparison usually reveals a very close relationship between geological structure and ore distribution, and can often lead to important conclusions which would not be reached in the ordinary working of a mine.The Triton mine lies 30 miles E.N.E. of Cue, or 380 miles N.W. of Kalgoorlie, in typical pre-Cambrian rocks, consisting of gTeenstone lavas and tuft's, interbedded with slates and some sediments, and intruded by granite and porphyry. Fig. 1 (at end of paper) is a longitudinal section of the mine and shows that the workings consist of the main North Emu and the smaller South Emu, separated by a distance of about 1 of a mile. Both orebodies occur on the same lode, which strikes north and south and dips practically vertically. On the same line, and of 1/2 a mile and a mile respectively to the north of the North Emu, are the small Rand and North Rand workings, where a big width of lode material has proved to be very low grade. In the North Emu the lode width averages 12 to 15 feet; it is seldom less than 5 feet and in places reaches 30 feet. In the South Emu the lode is wide, but only portion of it is payable.The lode is a mineralised bed occurring between massive lava flows on the east and a mixed series of tuft's and thin lava flows on the west. The lode material is hard, fine grained, and dark coloured, and generally has a faint banding which is believed to indicate a tuft'aceous origin of the original lode rock. Microscopic examination shows that the original lode rock has undergone considerable albitisation;' there has also been considerable formation of biotite which gives the lode material a characteristic sheen. The mineralisation consists of abundant fine pyrite, which is auriferous, and a lesser development of pyrrhotite which is, however, barren of gold.THE OREBODIES AND THEIR CHARACTERISTICSThe distribution of ore is best studied from gold contours, as these reveal features that cannot be detected in an ordinary assay section. Gold contours (see Fig. 3) are developed' by plotting the width and grade of all development and stoping assays throughout the mine on a longitudinal projection, representing each sample by a coloured dot according to a suitably chosen range of assay values, and then outlining areas of similarly coloured dots (see H. J. C. Conolly, Econ. Geol., April, 1936). Both width and grade must be taken into account and the simplest method of gold contouring is to use dwt.lft. values, but difficulties arise here with big widths of low grade and small widths of high grade ore. To choose an extreme case, 30 ft. of 2 dwts. and 2 ft. of 30 dwts. both equal 60 dwts.lft., and would therefore be given the same value in dwt.lft. contouring...

Jan 1, 1943

By C. C. Harris, A. Jowett, S. K. Ghosh

An equation derived from first-order kinetics and accounting for return from froth to pulp has correlated continuous flotation data. The concentration of floatable material in the pulp can be altered either by changing the feed concentration or the feed rate. The latter does not affect the flotation rate constant, the froth to pulp return constant, and the concentration of non-floatable material in both the pulp and concentrate. Both the return constant and the concentration of non-floatable material in the pulp are directly proportional to the feed concentration, while the concentration of non-floatable material in the concentrate is related to the feed concentration. The investigation of the froth flotation process by continuous test methods, previously used by Brown and smith,1 Jowett and Safvi2 and Jowett and West,3 is being continued. Recent tests, primarily concerned with flotation cell design, have yielded kinetic data suitable for testing an equation proposed by Arbiter and Harris4 which postulates that a flotation process is defined by two rate constants: 1) the rate constant for mass transfer from pulp to froth. Previous workers have regarded this as the flotation rate constant. 2) the rate constant for mass transfer from froth to pulp, which has previously been ignored. THEORY Under continuous flow conditions at the steady state in Fig. 1 the equation developed4 is Symbols are defined in Table I. The air-liquid ratio terms4 have been omitted, since they are substantially constant for a given set of conditions. Also, for a system operating at the steady state Vf and V, remain constant and Eq. 1 can be written: Cp/Cc=b'/a,+Qc/a' [2]

Jan 1, 1963