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By Bernard MacDonald

Of the treatment of the slime-pulp of gold- and silver-ores by cyanidation, agitation is an essential part. When prepared for treatment, this pulp, consisting of ore reduced to such fineness that approximately 80 per cent. of it will pass through a 200-mesh screen, is mixed with a certain proportion of water, carrying in solution the cluantity of cyanide (KCN) and other chemicals required. The water-constituent of the pulp thus prepared usually ranges from 1 to 2 parts by weight to 1 of the dry ore. Thus constituted, the pulp is charged into treatment-tanks, the shape and capacity of which vary, according to the quantity of pulp to be treated daily and the method of agitation to be employed. Tanks have no other function in a cyanide,plant than that of being economical and corlvellient containers or receptacles for holding the pulp, solutiou, or water used in the operations. It is by agitation that the solids in the pulp charged into the tanks are kept in suspension in, and mixed with, the solution in the proper proportions required for the treatment. If the proper mixture of solution to dolids be determined to be 2 to 1 by weight (which is, approximately, 5 to 1 by volume), this proportion should be maintained in every part of the charge; that is, each solid particle of the pulp, whether it be of' 180- or 400-mesh size, should be surrounded by five times its own volume of solution throughout the whole period of treatment. The reason is, that the amount of chemicals ascertaiued to be necessary for dissolving the gold and silver contained in the solids, is held in uniform solution in the water-constituent of the pulp, and, therefore, the determined proportions of solution and solids must be maintained at all times during treat-

Jan 1, 1912

By C. Ernest Birchenall, Robert F. Mehl

Application of diffusion laws in the customary form to experimental studies in binary metallic solid solutions has shown the diffusion cocfficient to vary with concentration for all systems investigated. The factors determining this variation have not been ascertained. However, the question of whether the diffusion coefficient would become a constant, independent of concentration throughout a single phase if the concentration gradient in the diffusion equation were replaced by an activity gradient has been an attractive subject for speculation. Wagner¹ derived an expression for the force acting on a diffusing particle in terms of the chemical potential. This was also the approach chosen by Jost2 in his monograph. From a somewhat different point of view, Eyring3 and his co-workers have used activity gradients when dealing with diffusion in concentrated nonideal solutions. The only actual test with experimental data is that given by Darken,4 though this is more qualitative than quantitative. Many others opposed the application in any way of thermodynamic concepts to kinetic phenomena, including diffusion processes. A rigorous examination of this principle requires good data expressing the relationship between activity and concentration for solid solutions for which reliable diffusion work has been done. The literature provides such information only for the interstitial solution of carbon in gamma iron (austenite) and for the substitutional copper-zinc solutions (alpha brass). Activity data for carbon in austenite at 800°C and 1000°C are available from the recent work of Smith5 on the equilibrium of hydrogen-methane and carbon monoxide-carbon dioxide mixtures with gamma iron. Combining these with the diffusion studies of Wells and Mehl6 makes possible a quantitative test for this interstitial solid solution. The vapor-pressure determinations for zinc over brass by Hargreaves7 allowed the calculation of activities in this system over a wide range of temperatures and concentrations. Extensive investigation of diffusion in this substitutional solid solution has been carried out by Rhines and Mehl.8 Activities in Brass9 If the vapor phase of zinc is assumed to behave as an ideal gas, any solid or liquid solutions that are in equilibrium with the same partial pressure of zinc at the same temperature have the same thermodynamic activity of zinc. In order to assign a numerical value to the activity azn, it is necessary to choose some standard reference state to which an activity value of unity is arbitrarily assigned. It is customary to choose the liquid or solid state of the pure material. Then azn is defined numerically by

Jan 1, 1947

By C. Ernest Birchenall, Robert F. Mehl

Application of diffusion laws in the customary form to experimental studies in binary metallic solid solutions has shown the diffusion cocfficient to vary with concentration for all systems investigated. The factors determining this variation have not been ascertained. However, the question of whether the diffusion coefficient would become a constant, independent of concentration throughout a single phase if the concentration gradient in the diffusion equation were replaced by an activity gradient has been an attractive subject for speculation. Wagner¹ derived an expression for the force acting on a diffusing particle in terms of the chemical potential. This was also the approach chosen by Jost2 in his monograph. From a somewhat different point of view, Eyring3 and his co-workers have used activity gradients when dealing with diffusion in concentrated nonideal solutions. The only actual test with experimental data is that given by Darken,4 though this is more qualitative than quantitative. Many others opposed the application in any way of thermodynamic concepts to kinetic phenomena, including diffusion processes. A rigorous examination of this principle requires good data expressing the relationship between activity and concentration for solid solutions for which reliable diffusion work has been done. The literature provides such information only for the interstitial solution of carbon in gamma iron (austenite) and for the substitutional copper-zinc solutions (alpha brass). Activity data for carbon in austenite at 800°C and 1000°C are available from the recent work of Smith5 on the equilibrium of hydrogen-methane and carbon monoxide-carbon dioxide mixtures with gamma iron. Combining these with the diffusion studies of Wells and Mehl6 makes possible a quantitative test for this interstitial solid solution. The vapor-pressure determinations for zinc over brass by Hargreaves7 allowed the calculation of activities in this system over a wide range of temperatures and concentrations. Extensive investigation of diffusion in this substitutional solid solution has been carried out by Rhines and Mehl.8 Activities in Brass9 If the vapor phase of zinc is assumed to behave as an ideal gas, any solid or liquid solutions that are in equilibrium with the same partial pressure of zinc at the same temperature have the same thermodynamic activity of zinc. In order to assign a numerical value to the activity azn, it is necessary to choose some standard reference state to which an activity value of unity is arbitrarily assigned. It is customary to choose the liquid or solid state of the pure material. Then azn is defined numerically by

Jan 1, 1947

By P. A. Riveros, J. Binvignat, V. M. McNamara, D. Koren

The recovery of cyanide from a gold mill solution containing high levels of copper (400 mg/L to 900 mg/L) using the AVR process was evaluated. It was determined that acidification to pH 2 to 3 provides a suitable balance between HCN generation, copper precipitation and acid consumption. A short pilot plant campaign showed that ~75% of the feed WAD cyanide was recovered while the remainder precipitated along with copper upon acidification. The acid consumption averaged 3.5 g H2SO4 per litre of solution. The copper precipitate, consisting mostly of CuCN and CuSCN, was readily separated from the solution by gravity. The volatilization of HCN in countercurrent packed columns averaged 98.7% efficiency. Reabsorption of HCN was practically 100% in NaOH solutions and slightly lower in a lime slurry. Basic volatilizer design parameters applicable to a large-scale operation were determined, including the Henry’s Law constant and the mass transfer coefficient of HCN gas.

Jan 1, 1998

By L. Flett, S. Woods, C. Deredin

"Following a significant reduction in world Imperial Smelting Furnace (ISF) capacity from 2003 to 2008, a major optimization initiative was successfully carried out on the lead upgrading and bulk (zinclead) flotation circuits in the Brunswick Concentrator.This paper describes the process improvements that have taken place in order to reduce the quantity of bulk concentrate:•,Increase in lead upgrading rougher flotation circuit capacity•,Installation of a closed-circuit bulk regrind utilizing MillPebs and 150 mm Cavex hydrocyclones•,Installation of two additional cleaner flotation stages on the bulk circuit•,Optimization of the manipulated variables in the lead upgrading and bulk circuitsINTRODUCTIONThe Brunswick Mine (Xstrata Zinc Canada) is located near Bathurst, New Brunswick and is one of the world’s largest lead/zinc mines. Milling of ore commenced in 1964 from the No. 12 orebody, with an expansion in 1966 to accommodate ore from the No. 6 open pit mine. The planned closure of the mine will take place at the end of the first quarter in 2013. The ore is a complex massive sulphide, consisting of approximately 20% valuable minerals, 60% pyrite and 20% silicates.A simplified flowsheet for the concentrator is given in Figure 1. The overall flowsheet involves SAG milling, secondary ball milling, selective flotation, and dewatering by thickening, filtering and drying. The complexity of the flowsheet evolves from the requirements for fine grinding and the production of four concentrates: zinc (sphalerite), lead (galena), copper (chalcopyrite) and bulk (sphalerite plus galena).Primary hydrocyclone overflow feeds the copper-lead aerator-roughers for flotation at pH 9.0 with soda ash. Plant xanthate (80-20 sodium isopropyl and potassium amyl) and AP407 are used as collectors in the copper-lead circuit. The rougher concentrate is directed to the copper-lead regrind circuit and the tailings are fed to the secondary grinding circuit. The secondary hydrocyclone overflow from the secondary grinding circuit feeds the copper-lead rougher-scavenger banks. Rougher concentrates are reground to a P80 of 28 µm prior to three stages of copper-lead cleaning. The first stage of cleaning is done in an open circuit with the tail reporting to the cleaner scavenger. The cleaner scavenger concentrate reports to the regrind circuit and the cleaner scavenger tail combines with the rougher/scavenger tail to feed the zinc circuit. The second and third stages of cleaning are performed in closed circuit with the cleaner tail being recycled to the copper-lead regrind circuit. The average final concentrate grades 23% Pb, 3% Cu and 704 g/t Ag, and is fed to the copper separation circuit."

Jan 1, 2013

By A. Janwong

Ion exchange technology is becoming more prevalent for metal recovery from low concentration solutions. The products of ion exchange are typically a metal free stream (product stream) and a concentrated metal stream (byproduct). The metals in the concentrate stream are usually precipitated and returned to the process or discarded. The unique features of emew® technology enable metals to be recovered directly from the concentrated stream. The advantage of the IX-emew® combination is the ability to have two product streams: 1) clean metal free solution and 2) metal product for sale. In addition to recovering metals from solution, it is also possible to separate metals from each other and recover more than one metal product. In this paper, examples of IX-emew® combinations are detailed including the recovery of copper, nickel and cobalt from an industrial waste stream, recovery of nickel from a spent electroless nickel plating solution and recovery of cobalt from an hydroxide cake.

Feb 23, 2014

By R. F. Hammen

Copper is one of the most widely used metals in industrial processes and is also present in most mining operations. Extraction of copper from solutions often proves difficult due to the presence of complexing agents. ChromatoChem, Inc. has developed a Solid Phase Extraction (SPE) support (HiPAC) for removal and recovery of metals from wastewater. The HiPAC SPE support employs chelating agents covalently coupled to a long linker molecule. Several solutions containing copper and complexing agents were tested including 1) copper and carbonate, pH 9.8, 2) mixed metals and anions with copper and cyanide, pH 11, and 3) copper and the chelating agent EDTA, pH 11. The copper was extracted from solutions one and two at high pH, but the EDTA containing solution needed the pH lowered to make the copper available for capture. In each example, the copper concentration was significantly reduced by HiPAC SPE treatment.

Jan 1, 1994

By Jianping Zhang

QUESTIONS: ?? Is it more expensive to find an ounce of gold in Canada today than 50 yrs ago? ?? Did the Canadian gold industry find more gold than they mined? ?? What is the future sustainability of the Canadian gold industry? ANSWERS: ?? The gold discovery costs in real terms only increased slightly from 1946 to 2000. ?? Though the Canadian gold industry mined more gold than they discovered in the period, when undeveloped deposits are taken into account, the deficit was merely 12 million ounces. ?? The Canadian gold mining industry would be sustainable in the foreseeable future, particularly, given the overwhelming predicted promising gold market in the mid/long run.

May 1, 2006

By A. C. Smith

The U.S. Bureau of Mines developed an experimental method to evaluate the relative effectiveness of water additives on the extinguishment of coal fires. The experiments were conducted in the fire zone of the multiple-entry section of the Bureau's Bruceton Experimental Mine. Four-hundred-pound Pittsburgh Seam coalbeds were ignited and allowed to burn until well-developed fires were achieved. Extinguishing agent-water solutions were then applied to the fires, and the quantity required to extinguish the fires was compared with the quantity of water alone required to extinguish similar fires. A 20% diammonium phosphate-water solution required an average of 5.8 gal to extinguish the coal fires, while two commercially available additive-water solutions required an average of 8.1 and 8.0 gal, respectively. The average amount of water required to extinguish the fires was 7.4 gal. An analysis of covariance, using the thermal energy of the coalbed to quantify the fire at the time of extinguishment, showed that the diammonium phosphate-water solution was slightly more effective at extinguishing these coal fires than water alone, and the two commercially available additive-water solutions were statistically equivalent to water alone.

Jan 1, 2010

By Joseph Pogue

THE writer visited the Muzo emerald mines in July, 1915, and spent six days in their study. This paper embodies the results of his observations, plus information personally communicated by Robert Scheibe, FIG. 1.-SKETCH MAP SHOWING APPROXIMATE LOCATIONS OF ALL IMPORTANT EMERALD MINES AND PROSPECTS IN COLOMBIA. (Data in part supplied by Robert Scheibe, July, 1915.) Professor of Geology in the Mining Academy of Berlin, who at the time of the visit was completing a detailed field investigation of nearly a year's duration of the emerald deposits of Colombia. An elaborate account of this valuable work may be expected at a future date from the pen of Professor Scheibe.

Jan 5, 1916

By V. G. Papangelakis

The implementation of a flow-through yttria-stabilized zirconia (YSZ) sensor for pH measurements in high temperature and concentrated electrolyte systems relevant to hydrometallurgical processing of nickeliferous laterites is discussed. Instrumentation involved the use of a custom made flow-through titanium electrochemical cell. Accuracy and validity of the pH measurements at temperatures up to 250C were assessed using concentrated sulphate process solutions ranging from synthetic binary sulphuric acid ? water solutions to progressively multicomponent metal ? sulphate solutions simulating laterite Pressure Acid Leach conditions. The measurements were also compared with theoretical models using recently obtained thermodynamic data. A difference of ±0.25 pH units was observed between measured and calculated pH values at temperatures. This is an acceptable difference given that these are the first direct high temperature pH measurements ever on the concentrated acidic sulphate solutions. This result is encouraging more research for the development of industrial electrochemical systems for direct pH measurements in autoclaves.

Jan 1, 2003

"The characterisation of resources and description of variability across different ore domains is key to accurate prediction of probable metallurgical performance. Such characterisation testwork often has limited drill-core from which to work and this immediately confines the characterisation method to smallscale. For flotation feeds, the JKMSI (Mineral Separability Indicator) is being developed as a potential characterisation tool, building on earlier work by Chudacek, (1990), which used shaken test tubes, and was called the EMDEE device. In addition, the consistency of flotation recovery for specified size fractions has shown to be preserved, irrespective of the amount of material in that size fraction obtained by different milling conditions, so that the overall recovery can be estimated from knowing the particle size distribution (McIvor and Finch, 1991; Bazin et al, 1994, Runge, 2007 and Wightman et al, 2010) The JKMSI unit uses less than 10 g of material per test in narrowly sized classes and results to date have demonstrated the value of the test. This paper discusses the potential of the test by demonstrating the link between JKMSI performance and mineralogy of five different ores from Laguna Seca, Escondida Minera Limitada as well as the correlation to plant scale performance obtained in an earlier survey (Coleman et al, 2006). Further work to tie down the proof of representatively of the small sample has been identified and is discussed and included in the paper. INTRODUCTIONSince the uptake of the flotation process at the turn of the twentieth century, small scale, laboratory methods have been sought to characterise flotation response. Although laboratory batch flotation tests are the most widely used method to evaluate reagents, characterise ore variability and obtain suitable model parameters using various scale up factors Runge (2101) other methods using less ore would be useful where ore samples were limited.A method using test tubes for testing ores’s flotation response to reagents was first developed by Ian Walk (Wark & Wark, 1935; Wark; 1938; Sutherland and Wark 1955). In these tests a 50 cc stoppered measuring cylinder served as a means for a qualitative experiment, the aeration being effected through violent shaking by hand. In these experiments about 10 g of mineral was ground by pestle and mortar under water after which the ground material was deslimed and adequately conditioned with the appropriate reagents."

Jan 1, 2013

By Onuralp Yucel, Osman Halil Celik, Hakan Morcali

In this study, some experiments were performed for the dimensional control, pre-treatment, getting salt, metallic aluminum and aluminum oxide into the solution of 15 kg aluminum black dross obtained from a private company which recycles aluminium drosses. Water leaching experiments are done for removing salts and aluminum nitride. Temperature stirring speed, solid-liquid rate are investigated while water leaching experiments. Removing of AlN is provided at 25 °C at a rate of 42.48%, at 80 °C at a rate of 86.4%. Leaching experiments performed with NaOH. NaOH concentration and time was analyzed. Efficiency of including metallic aluminum into the solution is determined to be 98% approximately. Melting (fusion) experiments were performed with NaOH at high temperatures to include aluminum oxide in the structure of the remaining after dissolving process into the solution and after dissolving the resulting structures in water, efficiency of including aluminum into the solution is determined to be 85%.

Mar 1, 2018

By Robert D. Pehlke, Robert G. Blossey

The solubility of nitrogen in liquid iron alloys containing chromium and nickel has been measured in the temperature range 1550° to 1700°C at nitrogen pressures to 1 ah. The solubility surface has been determined for the iron corner of the liquid metallic ternary to 21 pct Cr and 11 pct Ni. The nitrogen solubility increases markedly with increasing chromium concentration. The effect of nickel and the bilinear effect of chromium and nickel are less pronounced. The solubility data are presented, and interaction coefficients are determined from them. THE solubility of nitrogen has been determined in liquid Fe-Cr-Ni binary and ternary alloys. The work in this laboratory has been directed toward a relatively limited composition range, that is to 20 pct Cr and 10 pct Ni. Humbert and Elliott1 studied the entire ternary; but their investigation was, understandably, limited in this region. The region considered here is of the greatest commercial interest. Knowledge of the solubility in these alloys is important for accurate control of the nitrogen levels in various stainless alloys. Also, the solution behavior is of theoretical interest because of its deviations from ideal dilute solution rules at moderate chromium levels. The nitrogen solubility in the iron binaries has been reviewed extensively by Pehlke and Elliott,2 particularly with respect to the dilute solution interaction parameters. More recently, there has been some interest in accurate descriptions of solute interactions in non-dilute solutions. Most of the investigators have adopted a power series fit to accommodate any non-linearity of the data. The Taylor series expansion is adopted here, using Scimar's notation3 for the interaction coefficients. An alternate method, instead of requiring higher-order expansions, is to restrict the range of the composition variables. A planar solubility surface may be fitted to the data and its range of validity determined. If the axes of this region are displaced from the usual origin—the solvent pure iron—a change in standard state is required for the solution reaction. The standard state for nitrogen in iron is commonly taken as the hypothetical 1 wt pct solution of nitrogen in pure iron. However, for an alloy of appreciable solute concentration, e.g., 13 pct Cr or 18 pct Cr-8 pct Ni, it would be convenient to use that base composition as the solvent and redefine the solution reaction in terms of that particular solvent. A brief derivation follows, defining the free energy of solution in an alloy solvent. Following the treatment by Darken and Gurry,4 for a nitrogen pressure of 1 atm: N (pure component) = N (1 wt pct in solvent) [l] AG=RT ln100/ wt pct N in solvent Taking this reaction for an alloy solvent less the same reaction for a pure iron solvent the relation between nitrogen in pure iron and an alloy is: N (1 wt pct in Fe) = N (1 wt pct in alloy) [2] AG = RT[ln(wt pct N in Fe) - ln(wt pct N in alloy)] Adding ½ N2(g) to each side and subtracting N (1 wt pct in Fe) = ½N2(g), the total free energy for solution of nitrogen in an alloy, referred to nitrogen at infinite dilution, is given by: ½N2 (g) = N (wt pct in alloy) L3] AG°3 = -RT ln(wt pct N in alloy )PN =1 atm Interaction parameters have their usual meaning when ?G°/RT is differentiated with respect to the proper composition coordinate. If desired, the dilute alloy treatment may be utilized with the new reference composition as the solvent. This has. indeed, been done by Small and pehlke5 in their analysis of nitrogen solution in liquid 18-8 alloys. The Sieverts' technique was used for this investigation on an apparatus previously described.6 The materials used in this program were: Ferrovac-E iron, 99.95 pct, Crucible Steel Co.: chromium, 99.95 pct, Union Carbide Metals Co.; nickel, 99.9 pct, International Nickel Co. Recrystallized alumina crucibles were used with no evidence of crucible-melt reaction. RESULTS The locations of the ternary compositions investigated are shown in Fig. 1. The data of Turnock7 and small8 have been alluded to in other papers.5'6 There were no departures from Sieverts' law observed for

Jan 1, 1969

By Bohumír Cech, Jirí Hanika, Václav Veselý

"PET bottles are separated and subsequently crushed into flakes. Except for PET, these flakes contain PE, PVC, paper, adhesives, beverages remainders and mineral impurities. PET itself usually is a glycol and terephthalic and isophthalic acid polymer.The suggested method consists in PET flakes crystallization at 255°C. In the meantime, volatile substances evaporate and PVC disintegrates. Formed crystalline PET is crushed into small particles and then is subject to the basic hydrolysis at an atmospheric pressure. In addition to lye solution, glycol is added in the hydrolysis. Water is eliminated by boiling, which gives rise to suspension of sodium salt of terephthalic acid and glycol. The suspension is skimmed and the filtered glycol is vacuum distilled. Pure glycol is then the distillation product.Crystals are dissolved in water and the solution is filtered, which eliminates PE and impurities. Electrodialysis removes pure terephthalic acid salt from the solution. Glycol solution is returned to the hydrolysis. Terephthalic acid is precipitated by a mineral acid. Subsequently, it is washed and dried. The filtrate is separated through electrodialysis to lye and acid. The lye gets back to the hydrolysis and the acid is used for precipitation. Terephthalic acid and glycol are products in a “polymer grade” quality. The waste is a part of washing waters, distillation residues after glycol regeneration and a filter cake after the terephthalate solution filtration."

Jan 1, 2008

By John Dasher

Getting spodumene to float quickly and cleanly can be a problem. The author has presented an excellent account of a valid and useful approach to the scale-up of such problem floats. This indicated advantages for doubling retention time, i.e., buying another set of flotation cells. The author states that 21 pct of the spodumene floated in 2 min in the laboratory cell, that the grade of the rougher was about 75 pct spodumene, and that the final tailing contained 4 to 12 pct spodumene in different sizes with the present cells and 1 to 9 pct spodumene with twice as many cells.

Jan 6, 1959

By J. B. Hedrick

In 2004, rare earths were not mined in the United States. The major supplier, Molycorp, continued to maintain a large stockpile of rare-earth concentrates and compounds. Major uses for these commodities were in automotive catalytic converters, petroleum fluid-cracking catalysts, permanent magnets, glass-polishing compounds, ceramics, metal-alloying additives, phosphors and rechargeable batteries. Consumption of refined rare-earth products decreased. The United States was a major importer and exporter of rare earths in 2004. Yttrium was not mined or refined in the United States in 2004. Imports from China, France and Japan accounted for most of the U.S. supply of yttrium compounds for refined yttrium products.

Jan 1, 2005

By R. Unger, L. Mallett

The use of virtual reality (VR) technologies to train miners is an evolving area in research and development. In July 2006, representatives of 14 international organizations met to discuss current VR-related efforts and explore ways to employ VR in the future. This paper gives an overview of the various approaches presented at the meeting and discusses directions for future implementation. An example of a training package that teaches mine map-reading skills is presented. The meeting was the first step to building collaborations for furthering VR applications for mining. Planning has begun for a 2008 meeting open to broader participation.

Jan 1, 2007

By Ronald L. Bruening

IBC has developed a cost effective MRT process for the selective extraction and recovery of gold, copper, and a mixture of other base metals from mine leach cyanide solutions. This is a two-stage system in which the gold is first recovered selectively as a high purity salt. The copper is then recovered separately as a sulfate salt. The other base metals are then collected as a cyano anion concentrate. Three different SuperLig® materials are used. The first stage can be used alone on gold leach solutions where copper and other base metals are not a problem. The two or three stage system is used when the base metals build up in the leach solution, resulting in increased costs. The cyanide or cyanide/cyano anion concentrate can be recycled back to the leach solution until the build-up of other salts, etc. becomes too high, or this too can be controlled with a percentage bleed stream.

Oct 1, 2003

By Hu Wenjun, Li Maonan

Mine ventilation systems mostly are ventilation networks with fixed-quantity branches. The solution to the problem of ventilation networks with fixed-quantity branches is obtained by choosing the fixed quantity branches as chords and using Hardy Cross iteration method. The solution usually is feasible but may be not economical. This paper takes minimal annual ventilation electricity cost as an object, considering the power of main fans and boosters, natural ventilation pressures and resistances of regulators, and builds up a nonlinear programming model. A set of initial values of the nonlinear programming can be obtained by using Hardy Cross method, The MAP technique then used to find a set of local optimal solution The running procedure with a simple example is dicussed. Mine ventilation systems mostly are ventilation networks with fixed quantity branches. In the networks, air quantity of branches are generaly regulated by increasing branch resistance or air pressure. A comon approch to the of the networks with fixed quantity branches is to formulate it based on Kirchhoff's current and voltage laws and the solution is obtained by Hardy Cross iterative technique. The solution usualy is feasible but may be not economical. The optimal plan of air quntities regulation of mine ventilation network should be to make the solution satisfy both required quantity of work places and minimal ventilation operating cost. It is the purpose of this paper to introduce a new approch and computational experience of nonlinear programming of the optimal problem.

Jan 1, 1991