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By L. Bratek, K. Jaworek, M. Czaplicka

Methods for arsenic compound removal from aqueous solutions include processes such as: coagulation, adsorption, membrane techniques, electrochemical and biotechnology techniques. Advanced oxidation using both UV radiation and strong oxidizing agents such as ozone and hydrogen peroxide may also decompose these compounds. It is known that effluents from metallurgical processes contain inorganic arsenic compounds in addition to the organic compounds such as: dimethylarsinic acid and phenylarsonic acid. This paper presents the conditions that lead to the formation of deposits containing mainly arsenic, such as pH, the wavelength of the radiation and the type of oxidant, for this type of effluent.

Jan 1, 2014

By A. Brown

THIS P APER has been pre-pared as a progress report on Mines Branch investigations into problems of ground stress in certain co al mines of Western Canada. As such, it should be considered as a companion report to the one ( 1) presented to the Mining Society of Nova Scotia in 1956 and which dealt with similar investigations in the coal mines of Eastern Canada. For the past 50 years, dynamic incidents in the form of 'bumps' and 'outbursts' have been occurring in the coal mines of the Inner Foot-hills belt of tl1e Canadian Cordillera. As these phenomena generally become more frequent with in-creased thickness of overburden, a limiting depth of mining of 2,500 feet has been set (2) for estimating recoverable reserves of coal. If such a view were accepted, from a long-term viewpoint very large resources of coking-grade ?coal -in a part of the continent deficient in such coals -would not be available to the nation. The terrain in which these in-6dents take place may be described in geological terms as being dominated by pronounced structure in strata ?consisting of a large proportion of highly indurated rocks. The Geological Survey of Canada has co-operated by carrying out structural studies (3) at the mines, supplemented lithological by stratigraphic observations.

Jan 1, 1958

By B. Panton, J. Carvalho, E. T. Brown

High-capacity, post-tensioned anchors have found wide-spread use in initial dam design and construction, and in the strengthening and rehabilitation of concrete dams to meet modern design and safety standards. Despite the advances that have been made in rock mechanics and rock engineering during the almost 80 years in which post-tensioned anchors have been used in dam engineering, some aspects of the rock engineering design of high-capacity rock anchors for dams have changed relatively little over the last 30 or 40 years. This applies, in particular, to the calculations usually carried out to establish the grouted embedment lengths required for deep, post-tensioned anchors. These calculations which involve a number of aleatory and epistemic uncertainties, usually make simplified assumptions about the distribution and values of rock-grout interface shear strengths, the shape of the volume of rock likely to be involved in uplift failure under the influence of a system of post-tensioned anchors, and the mechanism of that failure. The resulting designs are generally conservative. These aspects of the rock engineering design of large, post-tensioned rock anchors for dams could be improved by making greater use of modern, comprehensive, numerical analyses in conjunction with 3D models of the rock mass structure, realistic rock and rock mass properties, and the results of prototype anchor tests in the rock mass concerned.

Jan 1, 2015

By G. D. Garland

The influence of natural electric currents, induced in the earth by changes in the earth's magnetic field, on the electric logging of boreholes has not always been recognized. Measurements made with fixed electrodes of changes in the vertical potential gradient in a hole near Calmar, Alberta, have indicated the effect of earth currents related to magnetic disturbances. It is found that appreciable errors in self-potential logging could arise during periods of magnetic storms, but the precise pat-tern of disturbance in any area seems to depend on the local structural conditions. As the amplitude of the natural earth currents increases toward the auroral zone, it is suggested that periods of magnetic disturbance be avoided, if possible, when electric logs are taken in the northern part of the western sedimentary basin. NATURAL electrical currents flow continuously near the surface of the earth, apparently as a result of electromagnetic induction

Jan 1, 1962

By D. R. Keck

"SINCE the .Canadian Chemical Company has no direct connection with mining operations, and I have had no experience with mining, there is little I can tell you that you do not already know. However, we have had considerable experience with certain types of metallurgical problems and I would like to discuss with you some of these problems and their solutions by our metallurgists.In order to acquaint you with the type of plant and processes to be employed at Edmonton, I would like first to take a few .minutes to trace briefly the history -of the Canadian Chemical Company's affiliate, The Celanese Corporation of America. In the early •part of the twentieth century, two young Swiss brothers, Camille and Henri Dreyfus, received their P.h.D. degrees in chemistry. They were extremely interested in work which was being carried on at that time to find a suitable synthetic fiber that could compete with natural fibers, both quality and price-wise. Early man-made fibers were both coarse and hard to dye. The Doctors Dreyfus• poured all their earnings into research and ultimately developed cellulose acetate filament. During World War I, the Dreyfus brothers were invited to the United States to produce cellulose acetate 'dope' for airplane wing coverings. Dr. Camille Dreyfus built the first American plant for fiber production at Cumberland, Maryland, in 1924.Due to resistance of textile mills to the new fibers, Celanese was forced to set up its own dying, weaving, and finishing mills to prove the new materials. Through the years, however, this operation has •been retained primarily for fabric development purposes,.. with the majority of the acetate being sold to other textile mills."

Jan 1, 1953

By A. McLean, A. Hue, K. Le, Y. D. Yang, P. Wu

While the treatment of relatively inexpensive ferrosilicon alloys is a potential refining route in order to generate solar grade silicon, phosphorus is one of the more difficult impurities to remove by conventional processing. In this project, the use of an electromagnetic levitation technique was used to investigate the dephosphorization of ferrosilicon alloy droplets exposed for various times and temperatures to a hydrogen-argon gas mixture. It was found that approximately 40% of the phosphorus was removed from an 85%Si-15%Fe alloy after 20 minutes exposure at approximately 1673K, to a gas mixture containing 48.5% hydrogen. Further dephosphorization is expected with longer reaction times. The effect of increasing temperature was found to be insignificant, although processing at lower temperatures is not only economically advantageous, it also decreases evaporative silicon losses, thus resulting in a more efficient process.

Jan 1, 2015

By Patrick E. Cavanagh

"A pilot shaft furnace was operated for one year at Steep Rock to produce special high-grade products from coarse ore, using lignite as fuel. The furnace is 10 ft in diameter and 60 ft high. When operated to heat coarse Steep Rock ore to drive off combined water and give a 64-per-cent-Fe product, the fuel consomption was 900,000 Btu's per long ton of product. The furnace was run in this way from September 1966 to January 1967 to establish the technique of feeding and discharging the furnace and controlling the gas composition and temperature. The furnace is similar in operation to a lignite water gas producer containing a large proportion of catalytic iron oxide. Steam injection is used to control the temperature. The product was tumbled in a rotary trommel to stabilize it. The resulting fines could be fed to the conventional pellet plant at Steep Rock. The furnace was next operated to make 77-per-cent-Fe metallized coarse ore. Several major modifications in de-sign were made and the furnace was successfully operated for short periods to maintain the required conditions to remove 75 per cent of the oxygen from the ore to give a 75-per-cent-reduced product at a grade of 77 per cent iron. The furnace cooling zone was operated under positive pressure, with internai alkaline water sprays to cool the charge. The product was discharged from the open bottom of the furnace without serions reoxidation. The metallized ore was magnetically separated from the discharge. Most of the charred lignite discharged along with the ore is re-cycled. Fuel requirement was 11,000,000 Btu's per long ton of product. This metallized coarse ore is intended for blast furnace feed. A short test run was carried out to establish the conditions for making a highly reduced melting stock for steel furnaces. To achieve 90 per cent reduction and over 90 per cent Fe, the furnace must be slowed down so that the production rate is about one-half the rate when making a 75-per-cent-reduced metallized product. Fuel requirement is 15,000,000 Btu's per long ton of product. The simple shaft furnace developed is similar to the top half of a blast furnace, with some major modifications to allow discharging into the open air. This Low Temperature Blast Furnace program has been technically successful and has resulted in making data available for the design of a commercial plant. Study of the commercial feasibility of large-scale production of metallized coarse ore at Steep Rock is still continuing."

Jan 1, 1968

By Subrata Dutta

Sindesar Khurd Mine is situated in Rajasthan, India, and operated by Hindustan Zinc Ltd, under Vedanta Group. The base metal mine is high in reserves of Lead, Zinc and silver and has been producing since 2007 with initial production of 0.3 mtpa. Recently the mine has gained prominence as a base metal underground mine in introduction of latest mining techniques and achieving high production at lowest costs. The promising Lead-Zinc reserves of Sindesar Khurd Mine (SKM) and high-tech exploration adopted by Hindustan Zinc Ltd (HZL), (Vedanta Group), raising the reserves and resources from a meager 9 Mt (1997) to 81 Mt (2012), has prompted HZL management to ramp up the mine production from 0.3 mtpa (2006-07) to 2 mtpa by 2013-14 with ambitious plans to reach 3.5mtpa subsequently (presently largest underground metal mine in India). The complete trackless system underground mine, recently equipped with latest leaky feeder communication system (unique in India), utilize modern drilling, mucking and hauling equipment aided with various utility/service vehicles. Excavation optimization and quality recovery maximization from the open and post filled stoping methods, continual expert analysis and feedback from International consultants like AMC (Australia) and SRK (UK), and involvement of renowned bodies in management excellence, have lead the mine towards highest productivity and lowest mine operating cost, earning the mine a prominent place in the global base metal industry. The paper deals with how the various challenges in mine planning and designing, mine development, operator skill, equipment introduction and maintenance, expertise availability, provide training and exposure to officials, prompt and effective communication/service, control of ground vibrations, maintain ventilation standards etc are faced in attaining high operational excellence and thus attain a record mine output/man shift (OMS) of 14 ton/man shift with targets to reach 20 ton/man /shift. Scientific designing using 2D/3D numerical mine-modeling techniques, faster stope sequencing with introduction of paste filling ( first time in India),latest leaky feeder communication system, control ground vibration to stringent standards using electronic delay system, faster raising techniques using raise borers to enhance development and ventilation, cavity scanners to monitor large stope voids, fast shaft sinking at 100 m/month(Chinese expertise) and maintaining adequate ventilation with close software monitoring are some of the highlights discussed in the paper towards achieving the targets.

Aug 1, 2013

By L. R. Fyffe, D. R. Lentz, S. H. Mcclenaghan

"Abstract - The Eel River area in the southwestern Miramichi terrane of New Brunswick contains a complete calc-alkaline suite of volcanic rocks that are interlayered with intervals of sedimentary and polylithic fragmental rocks, and are overlain by a thick sedimentary sequence. This package, collectively referred to as the Meductic Group, was deposited in a submerged volcanic arc setting interpreted to be part of the Popelogan arc. Rifting of this arc led to the development of the Tetagouche-Exploits back-arc basin, and formation of volcanogenic massive sulfide deposits in bimodal volcanic rocks of the Bathurst Mining Camp in the northeastern Miramichi Terrane. Unlike the Bathurst Mining Camp, volcanic rocks in the southeastern Miramichi Highlands form a continuous calc-alkaline suite characterized by increasing Zr/TiO2 with increasing SiO2, in part resulting from progressive coupled assimilation and fractional crystallization of nested magma systems. Slumping of semi-consolidated volcanic and sedimentary rocks in topographically unstable areas resulted in numerous slumps and debris flows that are preserved throughout the Eel River area. In the early 1990s, the discovery of a large sulfide clast in a road cut along the Benton road sparked interest in the volcanogenic massive sulfide potential of the Eel River area. Subsequent drilling intersected smaller fragments, one clast of which graded 16.7% Zn, 5.6% Pb, 90 ppm Ag, and 220 ppb Au. The intersection of thin lenses of stratiform sulfides in another drillhole indicates favorable conditions for the preservation of massive sulfides. Their subsequent incorporation into synvolcanic debris flows resulted in the transport and deposition of sulfide clasts from hydrothermal vents to more distal locations. Similar to the Buchans deposits of Newfoundland, tracing these debris flows back to their source would be beneficial from an exploration perspective. Approximately 15 km to the southwest of the Eel River area, gold-bearing base metal sulfide clasts (11.1% Zn, 6.13% Pb, 0.19% Cu, 108 ppm Ag, and 1100 ppb Au) occur within intermediate-composition volcanic rocks at Monument Brook in eastern Maine. Sommaire - Le secteur d’Eel River dans le sud-ouest de la terrane de Miramichi au Nouveau Brunswick contient une séquence complète de roches volcaniques calco-alcalines interstratifiées avec des roches sédimentaires et fragmentaires polylithologiques, sous une épaisse couverture sédimentaire. Cet assemblage constitue le Groupe de Meductic, et a été déposé dans un environnement d’arc insulaire interprété comme une partie de l’arc de Popelogan. Le rifting de cet arc à mené au développement du bassin d’arrière-arc de Tetagouche-Exploits, et à la formation de gisements de sulfures massifs volcanogènes dans les roches volcaniques bimodales du Camp Minier de Bathurst dans le nord-est de la terrane de Miramichi. Contrairement au Camp Minier de Bathurst, les roches volcaniques des hautes terres du sud-est de Miramichi constituent une suite calco-alcaline continue caractérisée par un accroissement du rapport Zr/TiO2 à des valeurs croissantes de SiO2, résultant en partie de l’assimilation progressive et de la cristallisation fractionnée de systèmes magmatiques superposés. L’effondrement de roches volcaniques et sédimentaires semi-consolidées dans des secteurs topographiquement instables est à l’origine des nombreux slumps et coulées de débris qui sont préservés dans le secteur d’Eel River. Au début des années 1990, la découverte d’un large claste de sulfures le long de la route Benton provoqué un intérêt pour le potentiel en gisements de sulfures massifs volcanogènes dans les secteur d’Eel River. Des forages ont par la suite recoupé des fragments plus petits, dont un claste qui a retourné des teneurs de 16.7% Zn, 5.6% Pb, 90 ppm Ag et 220 ppb Au. Le recoupement de minces lentilles de sulfures stratiformes dans un autre forage indique des conditions propices à la préservation des sulfures massifs."

Jan 1, 2006

By R. O. Burt

The original flowsheet of the TANCO mill consisted of a simple two-stage gravity circuit for the recovery of the tantalum concentrates. With decreasing grade and grain size of the tantalum minerals, considerable modifications to the circuit have been required. This paper discusses the various recent improvements carried out 011 all stages of the flowsheet, which have resulted in a 10% increase in recovery. Future improvements, including on stream analysis, and the possibility of tantalum flotation , are also discussed.

Jan 1, 1979

By L. D. van Dyk, G. S. Tshofu

Iron ore fines are by-products of iron ore mining operations. Unlike iron ore lumps, fines cannot directly be used in conventional iron making processes, and consequently large quantities accumulate around the world. Pelletizing and sintering can be used to convert iron ore fines into agglomerates or briquettes for processing with lump ore, but these techniques are energy intensive and produce greenhouse gases. This research investigated the extraction of iron from iron ore fines using acetylacetone (a ß-diketone) as an environmentally friendly alternative process for fines utilization. A 2k factorial experiment design was used to identify the significant extraction variables. It was found that the reaction temperature and solid to liquid ratio had significant effects on the extraction process. The extraction kinetics were studied at different temperatures and the highest iron extraction (97 %) was obtained after 48 hours at 413 K and 0.025:1 (g:mL) solid to liquid ratio for a particle size range of +106 to -150 µm. The extraction products were easily separated from the unreacted acetylacetone by flash distillation and iron(III) acetylacetonate crystals were recovered. An economic evaluation showed that selling the crystals was profitable. Alternatively, the crystals can be reduced with hydrogen to iron particles and acetylacetone (for reuse).

Jan 1, 2015

By J. D. Wright

This paper describes current milling practice at Endako Mines Ltd., a molybdenum producer in central British Columbia. The various steps in the crushing, grinding and flotation of the ore are outlined, with emphasis on the metallurgy of the latter operation. Tailings disposal and concentrate assaying methods are also described.

Jan 1, 1969

By J. E. Hawley, R. C. Hart

"The Preston East Dome gold mine is in the southeastern part of Porcupine district, Ontario, 5 miles southeast of Timmins, and immediately south of the property of Dome Mines, Limited.The claims now owned by this Company were originally staked in 1909. After the property had remained dormant for many years, the present Company was organized in 1936 to resume development operations. Two shafts had been sunk: at the time of the early work on the claims, but lateral work from these failed to reach the ore deposits. A successful diamond drilling campaign undertaken under the direction of D. G. H. Wright, however, was followed by the sinking of a five-compartment shaft arid the erection of a mill. From the start of operations to the end of 1944, 1,292,000 tons of ore averaging $11.60 in gold a ton have been mined.An outstanding feature in this mine is the occurrence of the major gold deposits in quartz porphyry intrusives, though minor deposits are also found in the adjacent Keewatin volcanics. Most of the ore occurs in fractures, but the filling was accompanied by varying degrees of replacement of schistose wall-rocks. The ore deposits may be classified as:"

Jan 1, 1954

By C. Turek, R. Henderson

Mine planning is the foundation of value for a mining company. Good mine planning requires solid understanding of the ore body, rigorous standards and processes, robust and useful information technology and skilled people. Life of mine planning is key to identifying strategic direction for any mine and short range mine planning is key to delivering forecast and budget expectations. Mine planning at Kinross has been identified as a critical success factor and initiatives are being prepared to improve the quality of our plans and to build bench strength in our teams. The Kinross Way for Mine Planning (KWMP) has been developed and implemented to establish the standards to ensure a strong business foundation. This paper briefly describes the process used to develop the KWMP and presents a selection of mine planning best practice initiatives at Kinross mines.

Jan 1, 2011

By Alireza Golabchi

The AEC (Architecture, Engineering, Construction) industry is an information intensive industry and all related processes employed during different phases of a project, including planning, designing, building, manufacturing, occupying, and maintenance, involve vast amounts of data that is used for a wide variety of purposes. Building Information Modeling (BIM) is a powerful shared knowledge resource which stores this data to support decision making about a facility through all these different phases in its life cycle. Nowadays, BIM is mostly used in the design and construction phases while it can also be highly beneficial beyond those stages. For example, in the Operation and Maintenance (O&M) phase, BIM could be used for automated facilities management or robotic inspection to provide semantic knowledge for navigation. For any implementation not related to the original intent of the BIM (design), organizations need to be able to represent their project data in a common interpretable form, which provides the possibility of an accurate exchange of data among different software products and platforms, known as interoperability. This study has investigated the current state of interoperability between software products used as Building Information Modeling tools. The main focus has been on a popularly used format for BIM models, Industry Foundation Classes (IFC), since it has been specifically developed to enable standardized data exchange. The research methodology involved a comprehensive literature review and the gathering of all fragmented prior research related to the field in order to develop a consistent understanding of the current state of knowledge. This was accompanied with a detailed case study that evaluated and compared two dominant pieces of BIM software, Revit and Bentley, and examined their interoperability strengths and weaknesses while using the IFC format.

Aug 1, 2013

By S. Flewelling, M. Scobie, G. R. Baiden

"SynopsisA feasibility study to develop a research program, the Mine Automation Plan (MAP), was recently completed. This was undertaken by a team comprised of Inco Ltd., Falconbridge Limited, the Canadian Centre for Automation and Robotics in Mining (CCARM) and the Centre for Resource Studies (CRS). The study was sponsored by PRECARN Associates, which is a consortium of thirty-six Canadian companies focussed on research and development in artificial intelligence and robotics. PRECARN Associates was formed in 1987 when a number of research proposals were funded in the fields of process control systems, robotics systems and intelligent engineering systems. In July 1991, PRECARN accepted the next round of proposals for research. The MAP project was one of the successful proposals, being awarded $100,000 for the development of a feasibility study defining a long-term R&D plan for underground hardrock mining automation.The development of the feasibility study started by addressing the fundamental structure of the mining process, and its relationship to the metallurgical process, over-all infrastructure support and management systems (Fig. I).Mining may be considered as comprising five subprocesses: (I) delineation; (2) development; (3) production; (4) backfilling; and (5) infrastructure support services. Within these subprocesses many applications for artificial intelligence and robotics exist. The mining process is dependent upon the interaction between the physical mining process and information. For example, the delineation process is dependent on geomechanical, geochemical and geophysical techniques to develop a model of the orebody based upon access to such data. This same relationship between the physical and information models holds true through the development, production, backfill and infrastructure support systems.The foundation for the MAP study has been the recent development by Inco Ltd. of an underground communications system (Fig. 2). The system has the ability to supply high bandwidth communications, over voice, data and video to mobile and stationary locations within the mining operation. It is seen to be the future backbone of a comprehensive, automated information system which should permit the application of the concept of Computer Integrated Manufacturing (CIM) to underground mining. CIM, through the automated flow of information, has been successful in integrating the engineering, production and various support groups in manufacturing."

Jan 1, 1994

By Sean McClenaghan

Significance Setting Size Production Value History of Discovery Zn and Pb at Austin Brook Brunswick Belt Exploration Discovery Hole Geology Structure Metal Zonation Directed Research Incremental Ores Precious metals Closure and Beyond Mining Remnants Tailings

May 1, 2013

By F. H. Edmunds

LLOYDMINSTER is the centre of a well developed agricultural area, lying on the Alberta-Saskatchewan interprovincial boundary in Township Fifty. The surrounding country is gently undulating, without any notable topographic features, but twenty-two miles to the north the North Saskatchewan river, and thirty miles to the south the Battle river, have cut deep valleys. In the spring of 1934, a wild-cat well (Lloydminster Gas Company's No. 1 well) was successful in striking a large flow of gas at a depth o 1,974 ? feet. The gas was piped into the town, a short distance south, and Lloyd-minster became the first Saskatchewan town to be served with natural gas. Following this discovery, other wells were sunk and, up to the present, thirteen wells have been drilled m what is here designated the Lloydminster area. Ten of these wells are in Saskatchewan and three in Alberta. Seven were successful in obtaining gas, three oil, and three have been unsuccessful. The area tested by this drilling is about eight thousand acres, six thousand of which can be considered as proved gas or oil land. To the south and west of Lloydminster, in the Province of Alberta, there are several areas in which oil and gas have been discovered. The Wainwright field lies nearly fifty miles to the southwest; Battleview, where recently gas has been discovered, is thirty miles west-southwest; and the Ribstone area is about thirty miles south and a little west. At Ribstone, a number of wells were drilled some years ago and there is a small production of oil. The data relating to the wells in the Lloydminster area that are recorded in this paper are taken from the records of the several companies operating in the field. The names of these companies are given on the map and on the type stratigraphic section (Figures 1 and 2). The author wishes to record his appreciation to Mr. R. H. Shaw and Mr. 0. C. Yates, both of Lloyd-minster, for much valuable information; also to Mr. E. Swain, of the Department of Natural Resources, Regina, with whom the writer has visited the field on several occasions, and who, by his enthusiasm and encouragement, has done much to forward the development of the area. The well samples were examined at Ottawa by officers of the Borings Division of the Geological Survey of Canada, who also made the interpretations of the logs. Frequent references will be made to the work of Dr. G. S. Hume, of the Geological Survey, and the writer would like to pay tribute here to his work.

Jan 1, 1940

By W. McCombe, G. Remple, L. Nightingale-Mercer

The McClean Lake Mill is located approximately 850 kilometres north of Saskatoon, Saskatchewan, Canada, and is operated by Orano Canada Inc. (Orano). The mill was designed to process high grade uranium ores, and a multi-year expansion was completed in 2014 to increase its production capacity to 24 Mlbs U3O8 per annum. The mill also underwent various upgrades to allow it to safely transition from processing low grade ores to high grade ores from the nearby Cigar Lake Mine. During the metallurgical test work on the Cigar Lake ores, it was identified that some ore zones of the deposit have a propensity to generate hydrogen gas during acid leaching. Hydrogen is a volatile and explosive gas, which poses obvious safety concerns in the leaching circuit. Uranium processing is further complicated by the fact that an oxidant in the form of oxygen gas or hydrogen peroxide is required to regenerate iron in the leach, which further increases the risk posed by hydrogen gas. During 2013 Orano and its consultant Hatch designed and engineered several novel upgrades to the leaching circuit to mitigate the risk of hydrogen gas evolution in the process. Best in class technology was utilized in addition to control and operating strategy changes to ensure the leaching circuit could be safely operated with ores that evolve hydrogen gas. This paper reviews the design concepts and modifications implemented on this unique and challenging project, and also provides an update on the operational reality of hydrogen in the circuit gained through five years of operational experience with hydrogen evolving ores.

Jan 1, 2020

By Norman Orr, J. W. Gregg, Jack Wahl

The Pembina Cardium pool is a low permeability, stratified, solution-gas drive reservoir. Water-flooding has proven to be an effective means of pressure maintenance for all areas of the pool in which an economic rate of water injection can be maintained. The majority of water injection wells in the pool are converted oil well~ with capacities greater than 100 millidarcy-feet. If the average injection rate per unit of capacity can be in-creased the lower capacity areas of the pool can be economically flooded. Theory, laboratory work, and two . early miscible-flooding projects with-in the pool suggested that average water injection rates for converted wells could be increased two to three-fold by the initial injection of natural gas liquids and natural gas. How-ever, these two early projects received volumes of natural gas liquid!:' and high-pressure natural gas which would be economically prohibitive for routine stimulation. Area D, one of the Five-

Jan 1, 1962