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By A. L. Engel

This investigation was undertaken to assess the feasibility of processing an extensive deposit of iron ore near Palisades, Eureka County, Nev., previously penalized for high phosphorus content. The experiments described indicate a satisfactory accomplishment of objective. Chemical treatment will permit a high-phosphorus iron ore to be used. Leaching with acid solution effectively lowers the phosphorus content with a [gligible] loss of iron. The use of hydrochloric acid is preferred because [ ] does not contaminate the ore and the cost is lower. Minus-1/2-inch ore was satisfactorily leached in 24 hours, minus-1/4-inch ore, in 8 hours, and minus-10-mesh ore, in 3 hours. About 40 pounds of acid per ton of ore was consumed in each instance.

Jan 1, 1959

By E. S. Leaver

Experiments dealing with the dissolution of silver by cyanide from various silver minerals were reported several yews ago.4/ This work showed that the silver in some silver minerals is completely and readily soluble in cyanide solution, whereas other silver minerals must be given special treatment before or during cyanidation to obtain much dissolution of the silver by cyanide. Flotation as a method for treating silver ores has not been studied much, except in the case of base-metal ores carrying silver, particularly lead-silver ores. However, many mills now are concentrating gold ores by flotation, and when such ores also contain silver the recovery of the silver by flotation is of considerable importance. Moreover, many mines contain ore in which silver is the principal valuable constituent. Some of these ores are amenable to cyanidation, but the cost of a cyanide plant may be prohibitive because of limited ore bodies or other factors. In such instances the successful application of flotation would mean that the property could be operated.

Jan 1, 1939

By I. Yu. Rasskazov, A. V. Rasskazova, N. M. Litvinova, N. A. Lavrik, V. G. Kryukov

The possibility of the intensification of the gravity processing of complex iron-manganese ore, which contains the finely dispersed inclusions of gold and platinum is shown. Clear mineral fractions of precious metals were sorted out of the different types of ores (quartz-braunite and carbonate- magnetite ore, ferruginous quartzite, carbon-containing shale, breccia-limestone and dolomite breccia). Composition and structures of precious-metals particles was detailed. The industrial content of platinum and gold was found. Precious-metals mineralization is character for all types of ores. High content of platinum is indicated in the carbonate-magnetite (up to 11.3 mg/kg) and quartz –braunite (up to 10 mg/kg) types of ore. Gold is presented in the ferruginous quartzite (up to 1.29 mg/kg) according to the data of the reduced mineralogical analysis. The composition of native platinum depends on the type of the ores: 1) quartz-braunite type contains isoferroplatinum (Pt3Fe) with Cu, Rh, Ir, Ru; 2) carbonate-magnetite type contains isoferroplatinum with Cu, Sn, Ni, Rh, Ir, Os; 3) pyritic-carbon ore contains isoferroplatinum with Sn, Ni; 4) ferruginous quartzite contains isoferroplatinum without admixtures. The ultrasonic treatment of mineral aggregates (P = 41.5 Watt, I = 15 W/cm2) made possible the liberation of fine particles of precious metals. Smooth-shaped or crystalline mineral aggregates are effectively liberated after acoustic treatment. Their surface is freed from impurities. The aggregates with the complex form and structure, which consist of the numerous plates and the grains, are not effectively liberated from impurities. It is shown that the ultrasonic treatment of aggregates with the fine inclusions of precious metals contributes to the liberation of the particles of platinum and gold and intensification of the gravity processing of refractory ore. This approach contributes the increase of the raw-material base of precious metals.

Jan 1, 2018

By B. R. Broekman, K. J. R. Ford

Over the last decade significant development and use has been made of a simulation model that describes the HCFeMn smelting operations in Assmang Ltd. This spreadsheet based, semi-empirical, predictive model is derived from data from the submerged arc furnaces at Assmang?s Cato Ridge, KwaZulu-Natal smelter site. Departures from the empirical base case mass balance due to changes in the ores, reductant feeds and operating parameters are accounted for by use of fundamental relationships and heuristic type ratios which are applied in an iterative manner in the model. The model performs a sequential set of calculations to iteratively converge on a fully consistent mass and energy balance solution, which predicts Mn alloy and slag output masses and compositions for a given set of feeds. 440 MWh per operating day is used as the basis of energy input. The paper describes the key model components, assumptions made and calculation approach. Added to the mass and energy balance is a cost and revenue balance, which allows prediction of the economic performance for each simulation. Substantial use of the model has been made in simulating the performance of the current Assmang HCFeMn furnaces for both smelter investigations and future production planning. The model has also been a valuable tool in the strategic analysis of the use of future Mn ores and has formed the vital link between mine ore grades (metal and slag elements) and the expected alloy output, grade and profitability. Additionally, the model has been used in benchmarking exercises to predict other Mn smelting operations with remarkable accuracy. The paper highlights some aspects of the approaches taken in using the model to benchmark Assmang?s own furnace performance and cost competitiveness with other producers. For Assmang the development and application of this modelling technology has led to transformation in understanding of the Assmang HCFeMn furnace operations and increased awareness of the potential of its Mn ore bodies.

Jan 1, 2004

In attempting to vegetate pnob!em sites some basic pn.i,ne%ptes, namely the phys.ica.e and chemi.ca2 pnope/ti;es og the problem mateni.al and the selection oU hu.itab.2e p!antts {cor pnopagati.on, have to be considered. Pnobtem sites such as tai ing dams, mined-out atteas, and areas which have been genehaUy advehse2y a46eeted by mining activities, are not only o~ten located in a divehs.ity o4 climatic regions, but they also usuaUy dL64en substantially in theAjt .int' Lns c phys.ica2 and chem.i cat pnopen t i.es . To estabP.ish vegetation on such sites 6requent2y requites: .%) The ame Lonaton oU adverse {yaetors in onde t to exeate a hoot env.utonment suitable Uon "satis1actony" plant growth. .%i) These.2eationo4 plant species suited to the improved Hoot env.utonment, and eompat%b&e with the e2imate o{y the site, and the ultimate Land use o4 the site. iii) The estabL shment o{y a Laboratory and p-LLot scale testing programme to aeeomptizh the above.

Jan 1, 1976

By R. I. Klintworth

The multi-reef area of Cooke 3 Shaft provides a unique mining challenge on account of the very thin middlings between the pay bands and the marginal values of the reef. It is uneconomic or impractical, because of the excessive heights, to mine the middlings using conventional stoping methods. The development of suitable mining methods is discussed with particular emphasis on the control of water inflow and the policy of not jeopardizing or sterilizing other reef horizons by the mining method implemented. No definite solution is currently available, but with the aid of instrumentation, computer analyses and mechanized mining equipment, the mine continues to attempt to maximize extraction and profits.

Jan 1, 1988

SOME 70 miles south-east of the of Auckland lies the town of Waihi-the centre of the Waihi goldfield, at present the mining pride of New Zealand. That the glory of most mining camps is evanescent forms an axiom to which it may be expected Waihi will prove no exception. For the last fifteen years, however, Waihi has been an important gold-silver producer, with an annually increasing output, so that now the area ranks as one of the leading goldfields of the world.

Jan 1, 1911

By H. B. Charmbury

In the United States and in Pennsylvania in particular the coal mine drainage problem is of continuing and growing interest to the coal mining industry, the state government, the federal government and the public at large. The 1965 amendments to Pennsylvania's Clean Streams Law prohibit the discharge of acid mine drainage into the streams of the Commonwealth after January 1, 1967. Because of this new legislation, the coal mining industry and state government are extremely aware of the necessity for new techniques for treatment and prevention of the flow of acid mine drainage from the active mines of the Commonwealth in order to keep the coal mining industry in business in Pennsylvania. Approximately one-third of the total volume of mine drainage presently polluting the streams of the Commonwealth originates from "active" coal operations and two-thirds comes from "abandoned" mine discharges. As early as 1963 it became evident that the Commonwealth of Pennsylvania and the coal industry in Pennsylvania would have to take active steps to abate the mine drainage pollution of Pennsylvania's streams and rivers. This became quite clear during the deliberations in Harrisburg which climaxed a twenty year struggle for effective strip mining legislation. The bituminous strip mining law enacted that year made it unlawful to have any acid discharge from active stripping operations.

Jan 1, 1968

By Heidecks C

Sub-level stoping with consolidated rockfill is the main method for mining steep dipping baryte and fluorite veins in Germany. Drifting is fully mechanised using drill jumbos, LHD units and shotcrete support. Stopes have heights up to 50 m with sub-level distances up to 15 m. Winning of the pillars between sub-levels is done by longhole blasting in slices of 3-5 m length on strike. Mucking is done on the lowermost level by LHD units. After each blast rockfill with binder (cement and/or fly ash) is dumped into the scope from the uppermost level. Economic success depends on both geological and technical parameters and factors, eg vein thickness and dip, ore grade, size and distance of sub-level drifts. Of particular influence are ore loss in pillar winning and dilution both in drifting on vein and in pillar mining. A comprehensive computer program has been developed for calculating the total cost per tonne run-of-mine ore respectively per tonne of concentrate for a single stope. The cost model includes development, longhole blasting, mucking and haulage to the mill, milling and ventilation. All costs (labour, energy, supplies, maintenance, depreciation and capital cost) are taken into account. Dilution and recovery are both considered. The program can be used to estimate the cost of mining a particular stope. It can also be used to investigate the influence of relevant parameters and factors on the economic result. By this way it should be possible to optimise the technical design of a stope.

Jan 1, 1995

By W. R. Bruce, R. W. Wittkopp, R. L. Parratt

Introduction The Relief Canyon gold deposit is about 24 km (15 miles) east of Lovelock at the south end of the Humboldt Range in northwestern Nevada. The deposit, is in the Relief-Antelope Springs mining district, which has historically produced silver, antimony, and mercury. There is, however, no mention in the literature of commercial gold production. Fluorite prospects at the gold deposit site have had no reported production. At Relief Canyon, the Late Triassic Grass Valley formation overlies and is in fault contact with the Late Triassic Natchez Pass formation. Epithermal disseminated gold mineralization is found within the various types of fault breccia between these two formations. Geology The Natchez Pass formation of Late Middle to Late Triassic age is composed of more than 300 m (985 ft) of massive gray to dark gray locally carbonaceous dolomitic limestone. Some minor beds of shale and siltstone up to 1 m (3 ft) thick are found in the project area. The limestone is locally silty or sandy. The color of this formation below the oxidation base ranges from gray to black and appears to be a function of carbon content. The Grass Valley formation of Late Triassic age is composed of more than 200 m (655 ft) of interbedded units of thinly parted argillite, hard gray to brown quartzite, siltstone, and shale. Within the oxidation zone, these units are olive gray. A few beds within this formation are slightly calcareous and a number of sections, especially those containing shale, are dolomitic. Below the oxidation zone, the quartzite beds are often slightly carbonaceous and the argillite, siltstone, and shale beds are often highly carbonaceous, giving them a black color. Two types of intrusive rocks have been recognized at the Relief Canyon deposit. Both appear to predate mineralization. Fine to moderately fine grained quartz monzonite dikes, up to 3 m (10 ft) thick, were encountered in several drill holes. In a number of intervals, these dikes have undergone either propylitic or argillic alteration. The age of these types of dikes is not known. It appears, however, that they are either Jurassic or Cretaceous. No gold mineralization has been found in this type of dike. Diabase dikes were also encountered in a number of drill holes. These dikes have almost always been propylitically altered. Although the exact age of the diabase dikes is not known, they are probably equivalent in age to the quartz monzonite dikes. Quaternary alluvium is found forming fans at the base of steep slopes and as recent fill in present day drainages. The alluvium is composed of either Natchez Pass limestone or Grass Valley quartzite and siltstone, depending on which unit served as the bedrock source. A significant portion of the Relief Canyon deposit is covered by Quaternary alluvium. Figure 1 shows a generalized geologic map of the Relief Canyon area. At the deposit's site, the Grass Valley formation appears to have been thrust over the Natchez Pass formation. The age of the thrust is probably correlatable with the Nevadan Orogeny, which gives it a Jurassic-Cretaceous age. The general strike of the thrust, referred to as the Relief Fault, is in a northwest direction. The strike of the bedding of both the Natchez Pass and Grass Valley formations roughly parallel the strike of the Relief Fault. The general dip of both the Natchez Pass and Grass Valley formations is in a southwest direction. The general dip of the Relief Fault, in the area of the Relief Canyon gold deposit, varies and has the appearance of a northeast-southeast striking anticline that plunges in a southwest direction. A small fold perpendicular to the plunge of this anticline forms a dome over the southerly portion of the Relief Canyon deposit. A number of northeast and northwest trending normal faults slightly offset the Relief Fault. Because of their small displacement, they are not shown on the generalized map. Gold Mineralization Gold mineralization occurs along the highly brecciated fault contact between the Natchez Pass and Grass Valley formations. Weak gold mineralization often occurs up to 2 m (6.5 ft) above the thrust in the Grass Valley formation. Most of the ore grade mineralization, however, is present below the Grass

Jan 11, 1984

By Stuart J. Schofield

Introduction The study of the ore deposits of British Columbia is one of fascinating interest not only from a scientific but also from a commercial standpoint and certain wide problems in connection therewith have interested me for some years. Several of these problems have been set forth in papers presented before this Institute on previous occasions. In 1918 it was pointed out that the commercial ore deposits of British Columbia, with one exception, were associated with the granodiorite batholiths of upper Jurassic age. This was followed, in 1922, by a discussion of the ore deposits of British Columbia in which the mineral belts of the province were defined and named, showing a zonal arrangement of ores in which the Pacific coast deposits are characterized by the presence of copper, while the interior belt is marked by the presence of silver, lead, and gold. Methods Of Investigation In reading various reports on the economic geology of British Columbia one is struck with the fact that the mineral veins may be arranged as a system and further examination will show that such a system follows two main directions, one northeasterly and the other northwesterly, both related in origin to the same force.

Jan 1, 1925

By E. Topuz

The objective of mine ventilation is to provide suitable environmental conditions in working places at an economical cost. Maintaining a stable air flow, i.e., a flow quantity and the direction, is of vital importance. In practice, however, air flow quantity in underground openings varies continuously. Therefore, the stability of air flow means relative stability that is the flow in a branch moves along a certain direction while the variation in air quantity stays within acceptable limits. Many underground mines have low stability of mine air flow because almost all types of ventilation systems involve complex diagonal branches through which air flow quantity and, more importantly, the air flow direction may change easily. This creates extremely hazardous, unstable conditions, especially during emergencies. This paper deals with the directional stability of air flows in underground mines in single or multiple fan systems. It examines the rules of directional changes of air flows in diagonal branches, and proposes a method of calculating the stability conditions. It provides a criterion that may be used in designing new mine ventilation systems to ensure a desired degree of stability or in improving the existing systems.

Jan 1, 1986

By M. E. Wadsworth, A. E. Lewis, R. L. Braun

Experimental results obtained in laboratory leaching studies of primary copper sulfide ore in sulfuric acid systems pressurized with oxygen are interpreted by a computerized geometric model involving the movement of a reaction zone through the ore fragments. Physical properties of the ore, including size, shape, and mineral content, are considered. The leaching mechanism involves mixed kinetics and includes a surface reaction within a moving reaction zone plus pore diffusion of dissolved oxygen through the reacted portion of the ore fragment to the reaction zone. The results are applicable to conditions that would exist in nuclear solution mining or similar processes in which the ore is converted into rubble and then inundated by a leach solution adequately supplied with oxidants. Experimental results at 90°C are correlated with the model, which includes temperature-dependent parameters.

Jan 1, 1974

By Johan F. W. Kock

"Hearing loss due to excessive noise exposure is the most prevalent industrial disease. It is ranked on the World Health Organization’s (WHO) priority list for major work related injuries. Uncontrolled noise not only has a physical effect, but is also a psychological hazard affecting the performance and well being of man. Noise induced hearing loss (NIHL) is irreversible, yet it is preventable. The first defence against noise (noise control engineering) is a high priority in the mining industry. Second defences should be a last resort when the engineering control of noise is inadequate. Hearing conservation programs and the use of conventional hearing protection devices seem to have failed in the prevention of noise induced hearing loss. If compensation payouts that quadrupled in the past ten years are used as a barometer for the success of existing hearing conservation programs, then new strategies and technologies need to be investigated. The best practice Hearing Protection Device (HPD) may be seen as the minimum standard for second defence noise control.Conventional hearing protection is widely applied, but also misused in the industry as well as in the mining sector. Empirical research results, ownership, general attitudes of workers as well as qualitative aspects will be explored. The paper provides reasons, evidence, case studies and strategies regarding the best practice hearing protection philosophy (the Noise Clipper Model) as implemented in the Implats Mining Group. Worldwide tendencies towards custom-made HPD’s, findings that indicate improvements in hearing conservation programs and finally the successful application of Custom-made Hearing Protection Devices, will be outlined."

Jan 1, 2003

By Raja V. Ramani, Sachin Shankar

"Re-entrainment refers to dislodgement of particles deposited by both atmospheric and nonatmospheric processes and their subsequent insertion into a flowing field. Formation of sand dunes, snow drifts, soil erosion and fugitive dust emissions are a few examples of the natural occurrence of re-entrainment. Re-entrainment studies have been done for the estimation of potential hazards from nuclear fallouts. The phenomenon of re-entrainment has been utilized for the cleaning of wafers and filters. Re-entrainment is associated with both surface and underground mining activities. However, studies on dust re-entrainment in mine atmospheres are limited. Understanding the re-entrainment phenomenon is important because dust particles lying seemingly harmless on the ground and adhering to numerous surfaces can get re-entrained and become a health and safety hazard.There are significant differences in the kind of re-entrainment encountered in underground mines and those in other fields of interest. These major differences are air velocity, direction of air flow, particle size, amount of particles, and time of exposure. While numerous studies have been done in other fields to identify the role of interacting variables and their contribution to the mechanisms of re-entrainment, no similar reported work is available for dust in mine atmospheres.In this paper, recent research efforts on re-entrainment are reviewed. The most suitable form of representing re-entrainment in underground coal mine atmosphere is presented. Various approaches to studying re-entrainment phenomenon in mines are also outlined.In the mineral industries, formation of dust particles of widely varying sizes is a natural outcome of the fragmentation required in mining the solid resources. Fine particles in mine atmospheres, particularly in the respirable size range, are a threat to the health and safety of the miners when present in high concentrations. In 1980 the National Academy of Sciences (NAS) Committee on the Measurement and Control of Respirable Dust in Mines recommended that the spatial and temporal characteristics (of fragments produced in coal mining) need to be understood so that the exposure of workers to the dust can be controlled. Recently several studies have been performed to understand the fundamental behavior of the airborne respirable dust in mine airways (Bhaskar, 1987; Qin, 1988; Polat, 1989; Bode, 1990)."

Mar 1, 1992

By Graham Swan

The case is presented for the development of a spray-on liner for ground support, but only in the context of a new mining system, consistent with the technical and business case advantages of liners compared to alternatives. Over the past 10 years much effort has been expended in specifying and testing the mechanical/environmental properties of various liners, without actually fulfilling any mining system requirements. The results have been generally disappointing, with no consistent and sustained application in a dayto- day production environment being achieved, anywhere. Central to this shortcoming has been the failure of mining/liner ma nufacturing companies to realise that screen/mesh or shotcrete cannot simply be replaced with thin, deformable liners: success will depend upon closely defining and evolving a new, liner- functional mining system. The paper begins with a discussion of some fundamental technical capabilities and constraints associated with 3M Canada?s liner material that has been developed in partnership with Falconbridge Limited. Intended applications for this liner include the support of bursting ground associated with deep mining conditions. With safe application and consistent performance in mind, the paper argues for a new mining system that derives in the first place from best quality drilling and blasting practices. Taking this as a given, a system for waterscaling and liner application prior to mucking out is proposed, followed by bolting through the liner while arranging for the bolts to be explicitly connected to the liner. Some logistical and equipment related challenges of such a mining system are then reviewed and discussed in the context of the business case for liners. It is concluded that this approach, if successful, will provide the greatest benefits in the areas of safer mining, due to reduction in worker exposure, and in reduced mining cycle times.

May 1, 2003

By R. T. O’Brien, J. M. W. Mackenzie

A microelectrophoresis technique has been used to measure the zeta potential of quartz over a range of pH and Ni (11) and Co (Ilj concentrations. Results have been discussed in terms of adsorption of Ni (11) and Co (11) cations and hydroxide precipitates. Possible relationships between the experimental results and the formation of lateritic nickel deposits have been discussed. The adsorption of metallic cations to the surface of silicate minerals is of significance in many industrial and natural processes. In an earlier publication,' the adsorption of Fe (111) to the quartz surface, a phenomenon of importance in flotation, was studied qualitatively using microelectrophoresis techniques. This paper reports the extension of this work to an investigation of the adsorption from aqueous solution of Co (11) and Ni (11) to the quartz surface. The adsorption of these metals was of interest for two reasons; firstly, the importance of such an adsorption process in the formation of nickel deposits by the lateritization of nickeliferous rocks, and secondly, the comparison of electrophoresis data for these metals, whose hydroxides precipitate in the pH range 7-8, with similar data for Fe (111) where the hydroxide first precipitates at pH 2.8. The development of laterites is essentially a near-surface geological process involving vertical and, in part, horizontal redistribution of elements derived from rock-forming minerals. This redistribution of elements leads to the formation of layers within the lateritic profile which are enriched in one or more of these elements and, depending on the nature of the original rocks, continued lateritization may give rise to iron ores, bauxites or nickeliferous laterites. The mechanisms discussed in this paper deal with the last mentioned type of deposit although the considered factors are applicable to laterites in general. Nickeliferous laterites are derived from basic and ultrabasic rocks containing ferro-magnesian silicates. These rocks may be partly or wholly converted to serpentinites. Besides their high Mg, Si and Fe contents, they also contain small amounts of Mn, Al, Cr, Ni, Co, Cu and Zn. The nickel content is usually near to 0.2-0.3%, but for economic use this must be increased during lateritization to over 1% and preferably over 2%. The zone of nickel enrichment is usually at some depth within the lateritic profile. Unpublished work by Mr. O'Brien on nickel-bearing laterites in eastern Australia indicated four visually different types of material which were separated from crushed samples under a stereo-microscope. Although chemical analyses indicated that all four types of fragments contained 2-4% nickel and smaller amounts of cobalt, X-ray diffraction and optical studies revealed only quartz, hematite and chromite as well as, in one of the types, a serpentine mineral. No distinct, nickeliferous minerals were detected. Furthermore, it was possible to extract some 60% of the nickel content of the laterites with cold 0.5N hydrochloric acid. It was therefore postulated that much of the contained nickel was present as amorphous, adsorbed material. In considering this fact, as well as the problem of the actual method of transfer and fixation of elements within the lateritic profile, it was further postulated that the transfer of these elements probably took place partly as solutions and partly as colloids and that the fixation of these was caused by adsorption and flocculation. The existence of nickel in solution in water draining from serpentinites has been confirmed by Smurov.2 Although we have no evidence for the transportation of nickel in the colloidal state, it is well accepted that colloids are important in the formation of laterites. Previous work by Mr. Mackenzie' has already indicated that iron may be adsorbed on quartz under conditions which could be expected in a lateritic profile, but no information was available for nickel or cobalt. Although adsorption possibly also takes place on minerals other than quartz, the latter is significant because silica is an important constituent of the silicate parent rocks. During lateritization, it is released to form free quartz and it is likely that it is initially extremely fine-grained. This would provide abundant opportunities for adsorption and it was de-

Jan 1, 1970

By Thomas R. Bur

The order of identification and in same cases the magnitude of the elastic constants of an anisotropic material depends on the orientation of the cartesian coordinate axes with respect to a set of reference coordinate axes within the material; thus confusion will result unless standard orientations are used. In this paper the relationship between the cause (the internal fabric) and the effect (the elastic properties in this case) is discussed for single crystals and for polycrystalline and amorphous materials. While reference axes based on the cause are used in the IRE (Institute of Radio Engineers) standard for piezoelectric crystals) it is shown that a reference coordinate system that would be suitable and practical for all anisotropic polycrystalline and amorphous materials must be based directly on a three-dimensional expression of the effect. The conventions offered are similar to the IRE standards for piezoelectric crystals) but use the elastic coordinates of the wave surface which can be quite readily established experimentally as the reference coordinates.

Jan 1, 1969

The production of petroleum in India (including Burma) increased from 334,811,624 gal.' ill 1936 to 350,322,222 gal. in 1937, the highest figure in the history of the industry. The increase in 1937 was clue to an increase of some 20 million gallons from Singu, 51/2 million gallons from Attack, 11/4 million gallons from Thayetmyo, and 1 mi1lien gallons from Digboi, accompanied by decrcases of 91/2 million gallons from Yenan-gyaung and 2 million gallons from Yenangyat,. The amount of gasoline produced from natural gas during the year was 10,616,313 gal. in Burma and 456,780 gal. in the Punjab. Yenangyaung Field.—The Yenangyaung field maintained its reputation of being one of the most wonderful oil fields in the world. The total production during 1937 was less than in the previous year but the resources of the field as a whole are sufficient to ensure an adequate supply of oil for many years. At the end of 1037 there were 2910 wells producing in the field. Besides a large number of ells drilled to shallow sands, this total includes 180 hand-dug wells, whose continued existenice is one of the interesting features of the field. During the year the deep drilling activities of 1936 in the southern part of the field died down, owing to the disappointing results obtained. On the eastern flank the limit of present economic extension of the oil sands was approximately demareated. Satisfactory results continue to be obtained from gas drives in the leased blocks; gas is also injected for repressuring and storage. Casing policies continue to be carefully designed to protect the oil sands against the danger of flooding by water and, in general, production methods throughout the field are characterized by a realization of the importance of the conservation of oil and gas and the prevention of waste, whether simple or underground. Singu Field.—-In 1937 the increase in the output from the Singu field was continued. This increased production was due not only to the rapid development of the valuable area in the southern part of the field but also to the successful results obtained from the first wells to produce from behind the practically completed river training wall of the Burmah Oil

Jan 1, 1939