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By Thomas M. Barczak

Longwall operators are again pushing the envelope in terms of life expectancy for longwall shields. State-of-the-art shields are now expected to last more than 60,000 loading cycles, twice the life expectancy compared with those of a decade ago. A review of trends in shield design shows that shields continue to increase in both size and capacity. Some state-of-the-art shields now weigh over 30 tons and provide up to 1,200 tons of support capacity. Although life expectancy has increased and modern shields are structurally more reliable, premature failures do still occur. This paper provides an engineering and operational assessment of shield design and provides key points to observe in what causes premature shield failures. Design practices to improve structural margins of safety that will prevent premature failures from occurring are also examined. A survey of recent shield failures is provided, as well as trends in shield design and how they might impact the performance and longevity of a shield. Hydraulic failures are more common than structural failures. Although hydraulic failures occur on all aging longwall shields, they often go undetected for long periods, resulting in degraded support capacity that can lead to serious ground control problems. The fundamentals of shield hydraulics are described in order to evaluate hydraulic failures that plague all shields at some point in their service life, and practical methods to detect hydraulic failures are examined. The paper concludes with recommendations for inspecting damaged shields and safety precautions regarding their continued use.

Jan 10, 2000

By A. F. MacDonald

The rugged foothills of the Allegheny Mountains in Washington County, Southwestern Pennsylvania, lend their terrain very well to the use of aerial tram systems to carry refuse from Bethlehem Mines' two preparation plants to disposal areas some distance from the plant site. Bethlehem Nines Corporation has three deep mines in this area, all of which are mining the Pittsburgh Coal Seam, The raw coal is prepared for metallurgical use in a preparation plant at each mine, Trio of these preparation plants, Mine No, 51, Ellsworth and Mine No. 58 Marianna, use aerial tram systems to dispose of reject material.

Jan 1, 1966

By Ioannis Paspaliaris, Dimitrios I. Gerogiorgis, Dimitrios Panias

"Red mud fiberization is a process with remarkable potential, alleviating environmental pressure by transforming an aluminum by-product into mineral wool, thus to various marketable products. A promising mineral wool process is molten slag fiberization via an impinging air jet, which avoids mechanical wear and rotating parts. The molten slag which remains after pig iron casting flows out of a heated ladle orifice at a high temperature (1600 °C) and adjustable flowrate, and forms a free-falling vertical jet which visibly radiates its excessive heat: at a given distance, a high-velocity impinging air jet meets the vertical melt jet perpendicularly (or at an angle), inducing intensive droplet generation, subsequent fiber elongation, collection and processing.This paper focuses on high-fidelity CFD modeling of the molten jet flow under external cooling: the model encompasses all physicochemical phenomena (melt laminar flow, radiative cooling) and considers several temperature-dependent slag transport properties in order to understand which operational degrees of freedom (manipulated variables) are useful to process optimization."

Jan 1, 2012

By Tom Learmont

The emergence of the dragline as the dominant stripping tool is described and reasons for this are noted. Brief comparisons are made with stripping shovels and wheel excavators. Representative output and machine availability figures for draglines are presented. The effect of changes in machine parameters such as boom length, swing power, and hoist power on machine productivity are discussed. An analysis of machine availability and the causes of machine downtime is made. Measures which are being taken to improve machine availability are discussed in detail. These include (1) improved methods of structural analysis, standardization of welded joints and welding methods to increase structural reliability and to develop more efficient structural designs, (2) standardization of gearing and mechanical componentry to permit the use of proven designs, (3) review of fairlead design and bucket hardware to improve rope life and reduce downtime, and (4) modifications to reduce maintenance time. The General Electric Data Logging system is described and consideration given to its use as a tool for improving productivity. Areas for future improvements in productivity are discussed.

Jan 1, 1976

By Ken Musgrave

"What Most Effective Management Does?It must satisfy the demands, of three groups of people: owners, employees and the public.OwnersOwners want profitable operations that will pay them a return on their investment, plus operations managed for long life. Many owners are also concerned with employee's well being and their company's public image.EmployeesJob security and a good income are probably still the most important demands, however, as time goes by, employees are also demanding more involvement in safety issues, working conditions, and even how work is done.The PublicThe public requires acceptable environmental standards, as well as enjoying the prosperity supplied by a successful operation.How are Mines Managed?Most mines are managed very traditionally. The basic credo is that the managers make the decisions, and the hourly, and junior salaried employees do what they are told. Clearly this is the extreme case, epitomized by the long service shift boss who might say ""It took twenty-years to become a shift boss, and no miner is going to tell me what to do"" .There are some exceptions, two notable ones being Campbell-Chibougamau, and T.G.S. (now Kidd Creek Mines) which, in very different circumstances, decided on a more participative style.Campbell-Chibougamau, having closed down due to unprofitable operations, reopened, using a team structure with working leaders, and a system for sharing gains against cost targets with employees. Although the system has some problems, and development miners are bonused conventionally, this has been a basically successful program.Texasgulf Sulphur, a company with a history of non-union operations, and a participative management style, made a corporate decision to operate their Kidd Creek Mine in the same way. The orebody was rich enough to allow them the luxury to do this, but they have never had a strike, so perhaps they have more than saved the cost of the benefits and salaries they needed to pay. They also reward employees with a stock distribution scheme based on service and earnings."

Jan 1, 1985

By K. Galovich, P. Krivokuca

"Quinsam coal mine is located about 25 km west of Campbell River on the east coast of Vancouver Island, British Columbia. Using continuous miners in a fully mechanized retreat room-and-pillar operation, it produces low sulphur, “super compliance” thermal coal for domestic and international markets at a rate of about 2600 t/d. Currently, 65 people work at the site, including some corporate employees.Opened in 1993, the Quinsam mine had a dismal safety record until 1997. Lost time injuries and medical aids were unacceptably high. In 1998, a change in corporate structure brought a change in safety attitudes; a total and unequivocal commitment to safety as job No.1 by corporate and site management. This commitment was clearly spelled out in a new mission statement, circulated to all employees by the new President and CEO, David Slater: “Safety is job No. 1; Production flows from safety; and Think safety at all times.” As well as re-defining workplace safety practices, QCC tightened engineering controls and enforced strict adherence to mine plans.This paper provides a general background to the mining operation, and describes the safety practices that have resulted in an enviable safety record in recent years, reflected by provincial and national recognition."

Jan 1, 2004

By N. Powell, R. J. Pine

An algorithm is proposed for updating the probability of slope failure on the basis of sequential testing using Bayesian probability theory. The approach is novel and computationally straightforward since, unlike other methods, updating of the probability of failure is carried out directly. This is because the probability is treated as a random variable whereas other methods have considered it as a purely deterministic value or as a function of shear strength parameters that are updated individually. The prior information required for the Bayesian analysis is obtained by a conventional probabilistic analysis. An exponential distribution is then used for the probability of failure, applying the principle of maximum entropy. This distribution is continually updated for individual slope cells, where repetitive excavation creates several such cells and a corresponding series of Bayesian estimates of the probability of failure is obtained. The approach is applicable to most simulations but there are limitations on its use. A more mathematically rigorous refinement using the beta distribution is currently under development

Apr 1, 1996

By R. Q. Honaker

It has been shown that naturally hydrophobic carbonaceous materials such as coal and graphite can be selectively coagulated and separated from hydrophilic impurities without using oily agglomerants, flocculants or electrolytes. The coagulation occurs at C-potentials significantly higher than those predicted by the classical DLVO theory, suggesting that it is driven by the hydrophobic interaction. In the present work, the energy barriers for the coagulation of a hydrophobic coal sample have been calculated using the extended DLVO theory which incorporates the hydrophobic interaction energy in addition to the dispersion and the electrostatic energies. For the coagulation of minerals present in the coal, the classical DLVO theory has been used for the energy barrier calculation. The results of these calculations provide an excellent correlation with the results of a series of Selective Hydrophobic Coagulation (SHC) tests conducted with run-of-mine coal and graphite samples.

Jan 1, 2004

By Charles Law McCabe, Lyndon H. Everett, Edna A. Dancy

It has been found that the carbide phase present at equilibrium in the system M-H2-CH4, at about 600°C, is MC for the rare-earth metals Ce and Pr. X-ray diffraction analysis showed that the monocarbides have fcc structures with lattice constants of 5.036 + 0.009Å and 5.131 + 0.001Å for CeC and PrC respectively. Gaseous equilibrium measurements were used to calculate the standard free energy of formation of the monocarbides from the elements. for the formation of (+ 1300) for the formation of PrC. THE rare-earthdicarbides, and their crystal structures, have been known for some years,l but only more recently were the carbides CeC,2,3 Ce2C3 2 and CeCS3 reported. In 1958 to 1959, Spedding et al. published work on the lanthanum-carbon system4 and other rare-earth metal-carbon systems,5 proving the existence of M2C3 and MC2, and measuring the lattice constants. They also demonstrated that tri-rare earth carbides, M3C, exist for the rare-earth metals samarium through ytterbium. However, they concluded that the cerium monocarbide reported by Brewer and Krikorian2 and by Warf,3 and given a fcc structure with a lattice constant of 5.130Å bythe former workers, was, in fact, cerium metal with carbon dissolved in it. They were also unable to find any evidence for the existence of Warf's CeC3, for which no structural details had been given. Even more recently, Palenik22 reported the existence of only M2C3 and MC2, having been unable to find any evidence for the existence of any other rare-earth carbides. There are no published experimentally derived thermodynamic data for the formation of any of these carbides, although Brewer and Krikorian6 have estimated values of for CeC, Ce2C3 and CeC2. The objective of the present investigation was; to determine experimentally the free energy of formation of any of the reported carbides of cerium and praseodymium, through a study of the rare-earth metal-hydrogen equilibrium. EXPERIMENTAL A methane-hydrogen mixture was circulated, in a closed system over previously prepared cerium or praseodymium hydride, and when equilibrium had been attained, the gas mixture was analyzed by selectively oxidizing the hydrogen and condensing out the water formed. The metal hydrides were used as starting material for convenience because, otherwise, the hydrogen in the gas mixture would immediately dissolve in the metals; in addition, the metals would not react with methane alone at the experimental temperature (around 600°C). The circulating system was based on that used by Browning, DeWitt, and Emmett7 for similar studies on iron carbides. It consisted of a quartz reaction vessel, all-glass circulating pump, analysis tube containing copper oxide that could be heated to 300" C by means of a small furnace, a solid CO2-methanol trap, and a double limb absolute manometer, Fig. 1. A cathetometer, capable of reading to 0.005 cm, was used to measure the difference in height between the two columns of mercury. In its final form, the reaction vessel was enclosed in an outer jacket, containing approximately the same pressure of hydrogen as that within, to reduce errors due to diffusion of hydrogen out through the fused silica of the reaction vessel., The circulating system was supplied with

Jan 1, 1962

By F. L. Wolf

THE catenary system of line construction possesses so many desirable characteristics from the operating standpoint that it has wide application for all types of electric traction. Many steam roads are electrifying sections of their lines, and in most cases are operating both steam and electric locomotives over the same track. This' means that the overhead catenary system is subjected to the severe corrosive action of locomotive smoke, and data concerning the resistance of various alloys to this form of corrosion are very desirable from every point of view. Reliable and specific information and data on the subject of corrosion due to steam and smoke from locomotives are extremely meager and, on this account, extensive service tests, together with accelerated tests, have been made on a number of commercial metals and alloys. The observations and data recorded in this paper are the result of a, preliminary test which was started in 1923 and which has been carried on to the present time. The recognition of the need for even more detailed and accurate data has resulted in the undertaking of another test which has been in progress for about a year. The result of this test will be published in due course. Some years ago The Ohio Brass Co. was asked by one of the large steam railroad companies to furnish data on construction details for a catenary system which it was considering for one of its divisions. The selection of, materials which would give the necessary physical characteristics as well as withstand the severe corrosive action of locomotive gases caused electrical railroad engineers considerable concern. At that time, there were available no specific or authentic data on these important questions: no systematic investigation of the problem appeared to have been made, even though its importance was generally recognized. Such observations as had been made were crude in that they had been limited largely to visual inspection which too frequently is most misleading. However, the scattered information which was collected gave important clues as to how best to start an investigation.

Jan 1, 1930

By M Yvon, S Parkes, K P. Galvin, P Wang

Mineral liberation is critical to maximise the grade and recovery of nickel, however this objective is challenged considerably by the poor flotation kinetics, especially that of ultrafine particles (Kelebek and Tukel, 2018; Multani and Waters, 2019). High recoveries demand long cell residence times and hence a large flotation capital expenditure (Wills and Finch, 2016). However, this leads to excessive entrainment of gangue minerals, thus negating efforts to depress its recovery. This study aimed to investigate new hydrodynamic approaches to improve nickel flotation, focusing primarily on unrecovered nickel from a Western Australian tailings stream. Mechanical cell flotation experiments were conducted to understand the flotation kinetics, covering different size ranges. A novel Reflux Flotation Cell (RFC) was also used to improve the nickel recovery and reject the silicates. Future work aimed at applying the RFC to different size portions is also outlined.

Aug 24, 2022

By D. K. Dysinger

Capital resource budgeting is the means by which managers of publicly held companies fulfill their fiduciary responsibility to maximize the wealth of stockholders. Managers maximize shareholder wealth by allocating investment capital to the most productive of competing alternative projects in a manner that maximizes the net present value of the firm's future cash flow. The techniques of cash flow analysis are the primary tools available for selecting a corporate portfolio of projects that meets or exceeds the rate of return expected by shareholders. The reliability of cash flow analysis hinges on the ability of managers to forecast the future values of individual components. The accuracy and reliability of forecasting determine the soundness of capital investment decisions and, ultimately, determine the value of the firm. The present paper will explore tools for forecasting the spot market price of a commodity, silver, to demonstrate the difficulty and uncertainty involved in forecasting the future. The commodity price is only one of a number of components of the cash flow equation. Each component has a unique and uncertain future and must be individually analyzed and forecast to arrive at a robust cash flow model.

Jan 1, 1997

By Benjamín Cebrián, David Flores, María Rocha Gil

This document shows the evolution of drilling and blast digitization process, savings and trends in a mine, using new technologies that creates business opportunities and general improvement of D&B process.

Feb 1, 2020

The question, Who won the war?, has been the text for innumerable newspaper, and magazine articles, the answers running from "bread and butter" to "poison gas," in a material sense, and from the "Y. M. C. A." to the "boys in the front lines," humanly speaking. Personally, I think the margin by which success was secured was so narrow that none of the complex, interdependent factors could have been .spared, and that, as Admiral Sampson said after the battle of Santiago: "There is glory, enough for all." But if any one human factor can be said to have been absolutely indispensable, I think all will agree that it was the engineer. The engineer, as a rule, is a modest fellow, so modest in fact and so averse to publicity of any kind that, referring to him as a class, he was hardly occupying the place he should in public estimation before the war. By way of illustration, in the early history of a mine in Bisbee, the chief owner was also the proprietor of a saloon and spent most of his time there. When asked why he did not pay more attention to the mine, lie replied: "Oh! I can hire a boy to look after that; it takes a man to run this bar." Comparisons of the position and pay of engineers with other occupations are sometimes made to show that the engineer is not getting all that he should, considering the time of preparation and the qualifications required. Perhaps at least a part of the cause may be his aloofness from many of the practical affairs of everyday life. Whether he won the war or not, the part played by the engineer has certainly placed him on a sort of pedestal in the public estimation at present and it is very desirable to keep him there and maintain the position he has made for himself.

Jan 9, 1919

By R. C. J. Goode, W. S. Rapson, W. R. Lawrie, L. W. P. Van Der Bosch

W. R. Lawrie (Member): As all the Institute members present are aware, the Ninth Commonwealth Mining and Metallurgical Congress was held in Great Britain from 3rd to 24th May, 1969. The Congress opened in London and the first week was devoted to technical sessions. Several receptions and other forms of entertainment were held in the evenings. The Congress was attended by some 1 200 delegates, many of whom were accompanied by their wives. As can be imagined a large organisation was needed to cater for all the whims of these delegates, to arrange accommodation and to provide transport for the technical trips, for the receptions and for the sight-seeing tours. Papers presented at the technical sessions proved of great interest. It was stimulating to hear of the developments taking place in the various branches of mining and metallurgy. The discussions which developed between men from so many different countries were thought provoking, led to new friendships and most of us made valuable contacts for the future. There were 141 papers presented in the one week. They were given in four separate halls with two, three and sometimes four papers coming up for discussion in each of the three sessions per day in each hall. Among the more interesting subjects were those concerning off-shore drilling and the facilities for production of petroleum and natural gas. Beach mining at Consolidated Diamond Mines drew a large audience. Automation, mechanization and other technical developments were well described and we were brought up to date with modern techniques of mineral prospecting. There was general discussion on the future of the mineral industries together with comments on the consumption and price trends of these metals and minerals. The future of uranium, of vital interest to us in South Africa, came in for much debate. During the first week, besides attending the technical sessions and seeing some of the sights of London, we were royally entertained. There was a banquet, attended by some I 400 people, where we were welcomed by Princess Alexandra, a reception by H.M. Government in the Banqueting House, and we were entertained at the House of Lords on a terrace overlooking the bustling and rather muddy river Thames. Then there was the visit to the Glyndebourne Opera. It is only in London that at 3 o'clock of an afternoon, nearly 1 000 people all togged up in dress suits and long dresses and carrying packets of sandwiches for supper could arrive at a station to catch a train, and not even cause a stir of interest or a raised eyebrow! This is the way we travelled 60 miles to the opera from London. Surely there can be no more picturesque or romantic a setting for an opera than this large 400-year old red brick manor house nestling in the green valleys of the unspoilt Sussex countryside. It was a glorious evening and though we returned somewhat late and tired, not one of us would have missed this experience. After the first week in London there was a choice of tours of one week to London and the Home Counties, Cornwall, a Geological tour to Scotland, South Wales, and North England. These were followed by further one week tours to Yorkshire and Lancashire, Scotland, West Country and Midlands, a Geological tour of Wales, and a Mining and Geological tour to Jurassic Iron Mines. We then returned to London for the final session and closing banquet. Post-congress tours were arranged to Europe and to Ireland. It was a wonderful Congress, a great experience, we made many friends and may there be many more congresses! . L. W. P. van den Bosch (Member): Much has already been said in appreciation of the excellent organisation and arrangements made for the delegates who attended this Congress. This report is confined to a brief discussion of the personal impressions gained from the papers presented and the technical visits attended. The papers covered a wide variety of subjects ranging from highly theoretical observations to practical descriptions of operations. There were three main themes, VIZ: 1. The attention given to research and its forceful application to practical operation. 2. A steady development in mechanization and automation leading to savings in manpower. 3. Improvization, modernization and adaptation of exisitng facilities. Thoughts on these themes can best be illustrated by comments on some of the industries visited. COAL The National Coal Board (N.C.B.) has been most progressive and all of us have heard of the Bevercotes Colliery with its completely automatic mining and coal handling equipment. This was not, unfortunately, on show but there is no doubt that this is one of the greatest advances in coal mining leading towards continuous production. Coal in Britain is fighting for its life against oil, North Sea gas, imported gases and nuclear power. Output is dropping, the less efficient collieries are closing down and efficiencies are steadily rising as the following tabulation indicates: In 1931: 1 million men produced 300 million tons of coal In 1947: 0.7 million men produced 230 million tons of coal In 1968: 0.4 million men produced 160 million tons of coal

By Jörn M. Seitz

Dynamic load testing is employed with ever increasing frequency to estimate the strength and elastic settlement behavior of piles of all types. For dynamic loading ram masses up to 20 Mg have been used and pile resistance forces up to 30 MN have been activated. Strains and accelerations induced by the impact are measured near the pile top and a load-set curve is computed by the so-called CAPWAP method. This paper briefly describes both the necessary equipment and other details of the dynamic tests and the available analytical tools for data interpretation. Furthermore the need for further research and the current status of standardization will be discussed. This paper also presents the results from several static and dynamic correlation tests on cast-in-situ piles of up to 2 m diameter and 64 m length. The results demonstrate the economical and technical feasibility of this test method.

Jan 1, 1987

By J. Petersen, T. Moyo

Waste Printed Circuit Boards (PCBs) are a metals-rich fraction of electronic waste (e-waste) streams, and globally it has been demonstrated that they can be recycled gainfully to recover the metals. Reported successful cases of PCB recycling are carried out in large volumes, using high-level technology and high capital investment smelter house operations. This presents entry barriers for recyclers in developing economies where capital may not be accessible, and the waste volumes are not sufficient to warrant large scale operations. Hydrometallurgical processes have the potential to provide an option for the scalable processing of smaller volumes of PCBs and can be set up at relatively lower capital costs. However, to date, the hydrometallurgical treatment options available rely on precursor communition and classification processes that also require high capital and energy costs. This paper presents an overview of the work done under the Minerals to Metals signature theme towards understanding e-waste recycling processes and developing pre-processing and characterisation of PCBs in order to unlock potential for local end processing in developing economies, using South Africa as a case study. The structure of PCBs is reviewed, and the current size reduction techniques and the subsequent leaching processes are discussed. Keywords: Printed circuit boards (PCBs), PCB structure, pre-treatment, liberation, ammoniacal leaching

Jan 1, 2020

By N. Campbell

"The fault under consideration follows a northerly trend past the west; side of the original settlement of Yell ow knife; which is situated 600 miles; north of Edmonton and 400 miles from the Northern Alberta Railway; terminus at Waterways; Alberta. The mining properties chiefly concerned; include the southern part of the Giant claims; on the east side of the fault; and the Con-Rycon-Demelt claims; on the west side 3 1/2 miles to the south.; Geological data were also obtained from the eastern part of the A.Y.E.; property; which lies south of the Giant claims; and from the Negus; Meg; Yellorex; and Kam properties; which are south and southeast of the ConRycon-; Demelt claims (see Frontispiece; also Fig. 5).Recognition of the major faults in the Yellowknife Bay area, including the West Bay fault, which appears to be the greatest, resulted from the work of A. W. Jolliffe (formerly of the Geological Survey of Canada) in 1935 and subsequent years. It has been stated with little exaggeration that these faults rank with the largest known steeply dipping dislocations of the earth's crust.In the winter of 1939, a mineralized shear zone named the 'Creek vein' was found on the Giant property. It was noted that the space relationship between this shear zone and a body of quartz-feldspar porphyry is roughly the same as that between the Con C-4 shear zone and a body of acid flows lying north of the Con property. Coupling this relationship with the assumption that the movement along the fault is dominantly horizontal, it was postulated that the Giant shear zone represented the faulted extension of the Con C-4 shear zone.As geological information became more extensive, certain weaknesses in this concept became apparent, and when spectacular orebodies were discovered on the Giant property in 1944 the question of possible faulted extensions became an important consideration. Consequently, in the spring of 1944, an extended investigation was undertaken, the results of which are embodied in this paper."

Jan 1, 1954

By Arthur A. F, MacKenzie I. H

Copper in zinc/lead sinter charged to the Imperial Smelting Furnace operated by Sulphide Corporation Pty Limited at Cockle Creek, New South Wales, concentrates in a complex lead dross which forms as the bullion is cooled to around 400°C. The 0.35 mm portion of this dross, containing approximatelY 67 per cent of the total copper, is treated via a hydrometallurgical route to produce 5000 tonne/yr of CuSO4 5H2O crystal.Around 3000 tonne/yr of copper-lead dross containing 49 per cent copper is leached at 55°C in continuous leach reactors with ammoniacal ammonium carbonate leach liquors to convert copper to soluble copper amine complexes. Leach ettlciencies of 80-85 per cent are obtained. Leach residues are repulped with ammoniacal liquid diluents from the plant and heated in a four stage steam distillation unit to reduce ammonia levels to between 0.5 and 1.0 g/Iitre. The resultant slurry is directed to an effluent treatment plant for final treatment, and separation and return of solids to the sinter plant.Copper is extracted from leach liquor by solvent extraction techniques based on the use of L1X 54 diluted 3:1 with Shellsol 2046 to give a nominal copper loading of 30 g/litre. The loaded organic is contacted with a sulfuric acid solution of pH 5 to remove the bulk of ammonia and zinc, then stripped at 55°C with a 60 g/Iitre H2SO4 95 g/Iitre copper solution to yield a 15 g/Iitre H2SO4 125 g/Iitre copper solution.This liquor is fed to an adiabatic vacuum crvstalliser operating at 35°C and 5 kPa vacuum where crystals of CuSO4 5H2O are formed. Crystals are separated from mother liquor and washed in a two stage pusher centrifuge, then dried in a hot air rotary drier. The crystal product obtained is of a high chemical purity and readily conforms to both Australian and overseas standards.

Jan 1, 1983

By G. Hileman

During the year 1934 there were no new or extraordinary developments in the proven fields. With few exceptions all companies operating in these fields continued intensive exploitation programs on their old properties in an attempt to maintain the normal production of former years. In one or two instances these exploitation activities have had such marked success that the total production for 1934 slightly surpassed that of 1933. The most striking increase in production is that shown by the Kilometer 27 pool of the Comodoro Rivadavia field. However, this increase cannot be attributed to intensive drilling, since it is the result of a more uniform daily withdrawal distributed among all the productive wells. The Province of Salta also showed another increase, so that, judging from the statistics of the past three years and in view of proposed exploration projects, the future may reveal some interesting developments in this province. One of the most interesting occurrences in Salta is the discovery, though not yet considered commercial, made at Macueta, near the boundary line between the Argentine and Bolivia. This exploration well was drilled by the Standard Oil Co. of New Jersey and is the northernmost exploratory well in the republic. The oil from this well is of the same type and commercial value as that produced in the San Pedro and Lomitas fields. The producing horizon is also the same as that in the other Salta fields; that is, the Paleozoic Permo-Carboniferous.

Jan 1, 1935