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By M. J. Friedel

The U.S. Bureau of Mines (USBM) investigated the use of seismic refraction tomography (SRT) for identifying changes in pillar loading at the Foidel Creek coal mine near Steamboat Springs, CO. The inherent three-dimensional problem of directly imaging coal pillar conditions is reduced to a single plane by considering only the load transmitted from the pillar to the adjacent floor rock. Floor strata velocity tomograms (at two pillar locations) illustrate that loading conditions are non-uniform and non-unique. Also, time sequence monitoring, as the longwall face advanced, demonstrated that SRT can be used to image spatial changes in loading conditions. SRT offers the mining engineer a simple and flexible technique for evaluating pillar conditions, and thus, both present and alternative mine designs.

Jan 1, 1994

By Vincent A. Scovazzo

The Pennsylvania Joint Coal and Gas Committee Gas Well Pillar Study of 1956 is the bases for well protection pillar design in the US and many other countries. An update was necessary because the well construction common to the gas and coal industries as well as mine configurations, mine depth, and extraction thickness have changed considerably since 1956. As initially envisioned the update would involve a similar empirical study that formed the basis of the initial investigation. However, there are no records of any gas or oil well failures related to coal mining since 1956 when mines followed the initial recommendation, making an empirical study problematic. Thus, the study had to be more analytical, which in return required at least some fundamental research into the behavior of the interaction of coal mining and oil and gas wells. A call to industry about research they have undertaken resulted in obtaining excellent research on the subject from three companies; Alpha Natural Resources, Inc., CONSOL Energy Inc., and Range Resources. These research projects were initially undertaken for internal use and not previously published. John T. Boyd Company reanalyzed these studies and determined how their results would affect protective pillar designs. These research projects pointed to the importance of horizontal movement and shear caused by subsidence and the strength of pillars and their foundations. The importance of geology is important in understanding horizontal shear, ground movement, and floor strength. The failure modes of casing and pipe needed to be understood so the threshold of these movements and stresses could be determined.

Jan 1, 2013

By C. J. Ramsburg

The construction and operation of by product coke-oven plants in America are essential to strong national defense and of the greatest importance to many widely diversified undertakings as well as to safety and health. Carbonization Process Coal used under a boiler or in a locomotive is consumed by combustion. Coal used in a by-product oven is distilled or carbonized, meaning that heat is applied to the coal, out of contact with air, causing a distillation that removes the volatile matter in the coal in the form of gas and vapor, leaving coke as a final product. From the gas and vapor distilled from the coal, many valuable substances can be secured, known as by-products. Hence the name "by-product oven." The simplest example of this principle can be shown by means of an ordinary clay pipe. If powdered coal is placed in the bowl of the pipe, the opening of the bowl is plugged with clay, and the bowl placed in a flame, the bowl will become hot, transferring the heat through the wall of the bowl to the coal within. When this coal attains a temperature of about 750°F., gas will begin to pour out of the pipe stem, and this gas may be lighted. A black liquid also will exude from the stem of the pipe, This is tar mixed with certain other products. What remains in the bowl after distillation is coke. A coke oven corresponds to the bowl of the pipe. A modern oven of the latest type is a refractory brick chamber approximately 42 ft. long and 14 ft. high, averaging 18 in. in width. The oven is filled with coal through closable charging holes in the oven top. Each end of the oven consists entirely of a self-sealing door, the removal of which permits the finished coke to be discharged by means of a power-operated pusher machine. The ovens are built in batteries, and the heating is effected by gas burned in vertical flues in the oven walls, each set of flues heating the walls of two adjacent ovens. Such ovens carbonize a charge of approximately 18 tons of coal in 18 hr., or have a daily throughput of 24 tons per oven, producing about 17 tons of coke. In times of need, the output may be increased by raising the temperature of flues, thus shortening the coking time. There is one great essential difference in principle between distillation in a clay pipe and in a coke oven. In the 18-in. oven, the distillation proceeds from two parallel walls held at a high temperature (over zooo°F.) and instead of all the coal being heated at once, the distillation is a progressive one creeping inward. The average travel of this heating is 35 in. per hour from each vertical wall, and as the volatile products are formed progressively they must push away from the interior toward the wall through the previously formed hot coke, then up the walls and Over the top of the coal charge, finally escaping through the outlet pipe. This results in a cracking of the components into many different and valuable substances not formed when the carbonizing temperature is low.

Jan 1, 1942

By C. J. Ramsburg

The construction and operation of by product coke-oven plants in America are essential to strong national defense and of the greatest importance to many widely diversified undertakings as well as to safety and health. Carbonization Process Coal used under a boiler or in a locomotive is consumed by combustion. Coal used in a by-product oven is distilled or carbonized, meaning that heat is applied to the coal, out of contact with air, causing a distillation that removes the volatile matter in the coal in the form of gas and vapor, leaving coke as a final product. From the gas and vapor distilled from the coal, many valuable substances can be secured, known as by-products. Hence the name "by-product oven." The simplest example of this principle can be shown by means of an ordinary clay pipe. If powdered coal is placed in the bowl of the pipe, the opening of the bowl is plugged with clay, and the bowl placed in a flame, the bowl will become hot, transferring the heat through the wall of the bowl to the coal within. When this coal attains a temperature of about 750°F., gas will begin to pour out of the pipe stem, and this gas may be lighted. A black liquid also will exude from the stem of the pipe, This is tar mixed with certain other products. What remains in the bowl after distillation is coke. A coke oven corresponds to the bowl of the pipe. A modern oven of the latest type is a refractory brick chamber approximately 42 ft. long and 14 ft. high, averaging 18 in. in width. The oven is filled with coal through closable charging holes in the oven top. Each end of the oven consists entirely of a self-sealing door, the removal of which permits the finished coke to be discharged by means of a power-operated pusher machine. The ovens are built in batteries, and the heating is effected by gas burned in vertical flues in the oven walls, each set of flues heating the walls of two adjacent ovens. Such ovens carbonize a charge of approximately 18 tons of coal in 18 hr., or have a daily throughput of 24 tons per oven, producing about 17 tons of coke. In times of need, the output may be increased by raising the temperature of flues, thus shortening the coking time. There is one great essential difference in principle between distillation in a clay pipe and in a coke oven. In the 18-in. oven, the distillation proceeds from two parallel walls held at a high temperature (over zooo°F.) and instead of all the coal being heated at once, the distillation is a progressive one creeping inward. The average travel of this heating is 35 in. per hour from each vertical wall, and as the volatile products are formed progressively they must push away from the interior toward the wall through the previously formed hot coke, then up the walls and Over the top of the coal charge, finally escaping through the outlet pipe. This results in a cracking of the components into many different and valuable substances not formed when the carbonizing temperature is low.

Jan 1, 1942

By Stuart Hammer

The mining industry has seen a flurry of merger and acquisition activity of late. Rising metal prices, increased spending on infrastructure in developing nations and the growing demand for companies to diversify have helped fuel M&A activity in this industry. Many analysts believe that the robust M&A activity will continue, particularly if the demand for mineral resources in India and China remains strong. Because prospective purchasers need to evaluate the various risks confronting target companies, acquiring mining companies requires a considerable amount of due diligence. Of these risks, environmental risk is critical and warrants significant analysis. The failure to properly assess environmental risks associated with remediation, reclamation, compliance or litigation can undermine the transaction. Such assessment is a difficult endeavor, however, due to several challenges that companies face when assessing environmental risks. To make matters more complicated, despite these challenges, many sellers ask buyers to assume all environmental risks with limited post-closing indemnification rights. This article addresses the most significant issues that commonly arise when conducting environmental due diligence and allocating environmental risk in connection with M&A transactions in the mining industry.

Jan 1, 2008

A mining engineer from South Africa, whose research has taken him to some of the world?s deepest gold mines, is the winner of the St Andrews Prize. Daniel Limpitlaw, 27, picked up a cheque for $25,000 for his dissertation on reversing the damage done by early mining technology, which he claims is partly responsible for blighting the urban environment in many South African cities. Launched in October 1998 by the University of St Andrews and international energy company Conoco, the St Andrews Prize sought practical solutions to environmental problems. It attracted interest from 450 individuals and groups from countries as diverse as China, Pakistan, Canada, New Zealand, Germany, the UK and the United States.

Jan 1, 1999

By Wm. I. Weisman

Sometimes in assessing where we are and where we are going it is informative to take a look at where we have been. Whether or not it adds to our understanding of the present, I think it may be interesting to review some of the past history of our industry. As a starting point I chose to use the famous Paley Commission Report, formally known as "The U. S. President's materials Policy Commission -Resources for Freedom."(l) The Paley Commission report said "Fluorspar is an essential raw material for the steel, aluminum, and chemical industries." Of course this statement is still true. It also said, "United States known reserves of fluorspar would be sufficient for some 15 years at present rates of consumption--about 426 000 short tons in 1960. Projected consumption for 1975, however, is several times as great, and reserves in other free countries do not appear adequate to supply United States deficiencies during the next 25 years." This simply demonstrates how even the most learned and competent people can observe all the facts avail-able to them at a given time and yet be unable to predict the future very accurately. We all know that reserves in other countries are more than adequate to supply the United States today, 25 years since the report was published. In fact, the report estimated free-world reserves at something over 36 million tonnes (40 million short tons). Contrast this with 246 million tonnes (271 million short tons) estimated as total world reserves from the section on fluorspar from Commodity Data Summaries of 1974, published by the Department of the Interior. (2) The Paley Report discusses other matters pertaining to fluorspar that are still of interest, such as improving mining methods. Furthermore, it certainly did a good forecasting job in noting that greater recycling should become possible in the aluminum industry in regard to fluorine lost in wastes and also concerning the substitution of fluorspar in the steel industry by other fluxing materials. It also suggested that non-fluorine containing propellants should be investigated as a replacement of those containing fluorine as a conservation matter. Some discussion was devoted to recovering the fluorine content of phosphate rock, which is being practiced today, but was in its infancy in 1950.

Jan 1, 1978

By R. R. Sayers

TWO serious hazards from coal dust confront the bituminous-coal miner- -a physical or safety hazard and a physiological or health hazard. The first threatens the miner with loss of life from coal-dint explosions, and the second with loss of health and earning capacity from inhaling large quantities of the dust. Studies by the Bureau of Mines have shown that coal dust, except some grades of anthracite dust, is capable of initiating an explosion when no explosive gas is present and that its property of extending or propagating an explosion has been responsible for nearly all the widespread explosions that have occurred in bituminous mines in the United States in the present century. For years many mining people believed that low-volatile coal dust was not explosive but not only is it explosive but if the source of ignition is intense, it is as explosive as the dust of many high-volatile coals because the war is creating increased pressure for greater coal production and because of the trend toward greater mechanization in mines, explosion and health hazards from coal dust are likely !n increase considerably.

Jan 1, 1943

By R Grobler, D Burger, L Alberts

The current climate in the mining industry is allowing mining companies to further broaden their views and investigate technologies to improve the safety, efficiency and cost-effectiveness of their operations. Furthermore, underground mine environments will become more demanding for mining equipment and personnel as orebodies become deeper in weaker ground conditions with more extreme environmental conditions. Loading and hauling can represent significant components of the production cycle of an underground mine and automation of these activities can offer considerable benefits. Sandvik has accumulated a long history and experience in loading and hauling automation in underground mining. Since the late 1980s Sandvik has actively participated in several major research and development automation programs leading to the commencement of the development of an integrated system for semiautomated loading in 1999. Development work was later conducted to expand the capabilities of the system for automated hauling during 2001 and the AutoMine« system became commercially available. The first delivery of the AutoMine« system was completed in August 2004 in South America, where the system continues to operate in a full-scale production environment and is being expanded as the production area enlarges. Further systems have been delivered and are operational in North America, Africa and Europe. This paper focuses on the AutoMine« system deployed in Block 4 at De Beers Finsch Mine in South Africa. An overview of the mine and the process used to acquire the system and the key drivers which led to the selection of an automated solution are described. An overview of the initial system installation, subsequent expansions and future plans are presented. This is followed by a summary of the implementation and operational experiences associated with automated underground operations. The paper concludes by summarising the benefits that have been realised.

Jan 1, 2008

By W. H. Adams

Shortly after becoming one of the van-guard of mine-developers in the State of Virginia, during the year 1883, I called the attention of the Institute to certain deposits of pyrites, which have been largely worked since. In all cases these deposits are covered with iron-ore (limonite), extending 40, 50 or 60 feet from surface to water-level. The several classes of brown iron-ores are found almost continuously along a prominent ridge of mineral-bearing slates, which can be traced from the James river northeasterly to the North Anna, the Rappahannock and the Potomac rivers, crossing the counties of Louisa, Spottsylvania and Stafford. Outcrops are plainly discoverable from end to end of this belt, also, in places, to the right and left of it, and at intervals there are evidences of workings, some of them for known purposes and others of unknown age and meaning. These old workings have an interest aside from the minerals they may contain or may have yielded. I have been engaged during the past five years in the collection of facts concerning them, which might determine definitely the site of those iron-furnaces, placed by tradition within reach of " the towne called Germanna," which were the first ever built in this State or on this continent. The events which led to the establishment of this important industry are sufficiently narrated in a paper written by Mr. R. A. Brock, Secretary of the Virginia Historical Society, and printed in the Proceedings of the National Museum, 1885, page 77, from which I quote the following : " To Virginia, the first of the English settlements in America, belongs the honor of inaugurating within her limits, as a colony, that most important industry, iron manufacture. "The London Company contemplated a variety of manufacturing enterprises from the very beginning of its authority; prominent among them was that of iron. In 1610 Sir Thomas Gates testified before the council of the Company at London, that in Virginia ' there were divers minerals, especially iron-oare,' lying upon the

Jan 1, 1892

By M. L. Leonardi

THE Searles Lake orebody is located in the north- west corner of San Bernardlno County. It is a dry lake bed with an exposed salt surface covering an area of 12 square miles. Recoverable mineral values are contained in the mother liquor below the surface of the lake. Stratification in the lake bed has separated the brine into two bodies which dlffer in composition. Although liquor is processed from both bodies, this paper will discuss only the upper structure brine. Fig. 1 illustrates a typical cross-section of the two commercial orebodies. The orebody is composed of a porous salt deposit 70 to 90 ft deep. The upper structure is separated from the lower orebody by a 12 to 16-ft thick impervious mud seam, as shown in Fig. 1. These salt structures are composed of 55 pct solid-phase salts and 45 pct voids which are filled with the original mother liquor. The brine wells are drilled to the separating mud seam and cased to wlthin 10 ft of the bottom. This is done to draw the brine horizontally from the bottom of the structure. It is pumped with multistage centrifugal pumps Into the plant at the rate of 3 milllon gal per day. The first process that was successful was developed by Charles P. Grimwood for the recovery of potash. The first evaporator unit was built in 1916. In the early twenties, Dr. Morse worked out a process for the recovery of borax. This made the cycle more efficient, as the end liquor could be sent back to the evaporators rather than being sewered. In 1926 the American Potash & Chemical Corp. was formed as a new company, and the entire plant was remodeled. The plant at that time produced only potash, borax, and boric acid. Since then the American Potash & Chemical Corp. has added processes for the production of USP boric acid, refined potash, sulphate of potash, soda ash, salt cake, lithium concentrates, Pyrobor (Na2B4O7) bromine, phosphoric acid, and lithium carbonate. The main plant cycle may be depicted as a closed cycle, see Fig. 2. The raw material, brine, enters the cycle to be mixed with the end liquor, known as ML2, from the pentahydrate borax crystallizers. The mixture of these two forms evaporator feed. Evaporator feed is pumped to the evaporators where it is concentrated, with respect to potash and borax. In the same operation water vapor, sodium chloride, salt trap salt, and clarifier salt are removed from the cycle, see Fig. 3 for potash plant product. The evaporators produce a concentrated liquor which contains approximately 19.5 pct KCI. This liquor is diluted as it enters the potash plant to keep all salts, except potash (KCI, 97.0 pct) in solution. Here the moist potash leaves the cycle at 100°F. The end liquor, known as ML1, is pumped to the borax pentahydrate crystallizers, where crude borax pentahydrate is crystallized and removed as solid phase. The ML2 is sent back to pan feed to be reconcen-trated, see page 207. Note that the only water to leave the cycle is in the form of vapor and moisture in the solid phase products crystallized. Thus there is a constantly cycling volume of liquor to which brine is added. Since the volume of liquor cycled does not increase, the brine is, in effect, evaporated to dryness. This would be true if there were no liquor losses. But, as in all processes, there are always unavoidable and accidental losses which reduce the volume of cycling liquors. The losses must be made up with brine. The concentration process is the beginning and the end of the cycling liquors. In this process there are three evaporator units of the triple effect counter-current type, that is, there are three pans in each unit and the heat flows in one direction while the liquor flows the other way through the evaporator pans, see Fig. 4. During the evaporation process a great deal of sodium chloride, burkeite, some sodium carbonate monohydrate, and a little lithium-sodium phosphate are crystallized. The volume of these salts is so great that they must be removed as they are formed or the process would come to a standstill. Brine and recycled mother liquor No. 2 enter the third effect evaporator pan from the evaporator feed storage tanks, see Fig. 5. A steady flow of liquor is removed from the bottom of the No. 3 pan and is pumped through the No. 3 cone of the salt trap, a clear liquor being returned to the NO. 3 pan. A portion of this clear liquor is pumped to the second effect pan. This process is repeated in each pan. The liquor from the No. 2 pan is pumped through the No. 2 salt trap cone and returned to the No. 2 pan.

Jan 1, 1955

By R. C. Miranda

Artificial vision systems are increasingly used to assist humans to perform different tasks in different areas. These systems are able to recognize patterns in complex images, which can provide multiple data. Currently, vision systems are used in both; monitoring traffic - which uses radars for vehicular plate recognition- as in metallurgical and food industries for strict quality inspections. Their use in mining occurs in measuring the speed of froth over the lip of a cell, in determining the shape and size of pellets, in obtaining from the tendency of mineral content and as a replacement for laboratory analysis of particle size. With this advanced tool, it is possible to achieve significant improvements in quality, productivity, and especially in reducing costs in pelletizing plant of iron ore. The objective of this paper is to contemplate the current situation of image analysis in the pelleting plants and glimpse at the potential applications that are being developed. This paper also presents the conception and implementation of an automatic control system of the pellets size distribution applied on a pelletizing plant of iron ore. The article demonstrates the strategy used for measuring the size distribution of the iron ore pellets, based on image analysis and the strategy implemented on advanced process control, which shows substantial gain on plant performance.

Sep 1, 2012

By ALICE V. Petar

Like many gem materials, amber has a colorful history which may be traced through the writings of the ancients and the ornamental relics discovered from time to time. Like few gem materials, however, it is distinctly useful in products whose value has no connection with the gem industry. Long prized for its beauty, amber was fashioned into articles of jewelry and ornaments to please the fancy of ancient rulers and to find a place among treasured pos- sessions in their tombs; it has been used by adherents of various creeds for rosaries and other religious symbols; and although still sold for these pur- poses it also lends itself to such commercial purposes as raw material for varnish. Amber is only on the border-line of the mineral kingdom; actually it is of vegetable origin, having been formed as resin from trees of the conifer family that existed during the Tertiary period. It is the hardest of the fos- sil gums. The United States produces no amber, although a few occurrences are known. Most of the world's supply comes from East Prussia, where it is ob- tained from both land and sea. For many years pieces of amber were gathered from the Baltic by fishermen and deep-sea divers; and although about 10 per- cent of the Prussian amber is still recovered from the sea, most of the out- put is mined from open pits on the Samland Peninsula.

Jun 1, 1934

[ALBERTA, UNIV. OF AZIZ, Khalid FLOCK, Gerald L HART, Richard T NAOER, Walter SCHEIDEGGER, Adrian E SHIELS, David Alexander ALUMINUM CO. OF AMER. GAYLE, Douglas Z MINTER, John L MOORE, Thomas C NEUSTAEDTER, J A REISS, Royal W SPEYRER, Henry R AMARILLO OIL CO. BEST, John B Jr COX, Arthur F GRAY, Stanley F Jr KEENS, Roy J MORRIS, Edward S TIPTON, J A WHITIS, Thurman S]

Jan 1, 1961

By Flavio Rojos-Tapia, Samuel Sánchez-Pino, Marcelo Fernández-García, Samuel Sánchez-Baquedano, Rainer M. Imhof

"Pneumatic flotation was introduced to the Chilean copper mining industry in 1993 by Ingeniería de Minerales S.A., being implementation in 1994/95. The technology is based on the designs and development of Dr. Rainer Imhof from Germany and from Chilean copper processing experience.Pneumatic flotation has been successfully used for sulphide and oxide copper minerals and copper slag, iron ores (reverse flotation), gold and promising results with molybdenum as product. Extremely hard conditions were applied in flotation process such as roughing, cleaning, scavenging. Pneumatic flotation can be applied for any type of mineral which has to be separated by flotation. Even very dense and heavy slurries can be processed, the range of the particle sizes to be collected is very wide, and the number of cleaning stages needed normally is one in our experience until now.The good performance of the technique can be explained by the high gas hold-up and the very effective micro-turbulences which boosts the attachment to the bubbles changing dramatically the flotation time concept. Some economic high lights are: less energy consumption, less maintenance costs, simple and reliable to operate and it is required a small area to install the circuits.As a result of the Chilean mining industry experience, it can be concluded that the pneumatic flotation can be regarded as an excellent alternative to the conventional way of Mineral Processing.INTRODUCTIONDerived from seventies, works in Germany about pneumatic flotation with Prof. Simonis (Technical University of Berlin) and Prof. Bahr (Technical University of Clausthal), it has been developed an interesting flotation technology in Mineral Processing, with the designs developed by Dr. Rainer Imhof, who has been known for more than ten years (Imhof, 1998) by his contribution at Ekof, KHD, Allmineral and the actual company Maelgwyn Mineral Services where he is a Technical Director. Ingeniería de Minerales S.A. has been working ten years deeply involved with the technology developed by Dr. Imhof and is more than ten years experienced with pneumatic flotation, from Wits University and Mintek in South Africa (Sánchez, 1990), (Sánchez, 1990)."

Jan 1, 2003

By J. A. Lombardi

Innovative hard rock narrow-vein, longwall, and stope leach mining systems concepts are described and evaluated economically. The principal tool proposed for use in these systems for both mine development and production is the U.S. Bureau of Mines radial-axial splitter. The mining systems concepts are prefeasibility level costed and projected to be cost competitive for steeply dipping veins, 0.6-1.2 m wide, for horizontal tabular ores 2 m -5 m thick, and for leachable ores with greater than a 1.7:1 stripping ratio. In all of the systems the orebody, less swell, is retained underground for use as backfill.

Jan 1, 1994

By P. C. Clark

This paper is an overview of the requirements and concerns for minerals and pigments used in papermaking. The first part of this paper deals with mineral or pigment filling in the actual papermaking process. The second part deals with the pigment or mineral properties that are important in today's coating processes.

Jan 1, 1993

By K. J. Craig, M. A. Swart, Q. G. Reynolds, L. Hockaday

A solar reflector soiling study was carried out at a ferromanganese smelter in South Africa to assess the soiling rates at different locations around the plant. Several meteorological parameters were monitored to give insight into the conditions that lead to increased soiling. Mineralogical characterization of dust samples collected from the reflectors and the atmosphere revealed that only a certain size fraction is of importance with regard to soiling, and that the dust can be attributed to both raw materials and smelter products. Proximity to the dust source was the primary driver for increased soiling. The site that experienced the most soiling was very close to raw material heaps; this was deemed an outlier and was excluded from the summary statistics. The secondary driver for increased soiling was location relative to the smelter dust sources and the wind’s direction and speed. The reflector set at the best location experienced 13.1% less soiling than the set at the ‘worst’ (but still feasible) location, represented by an averaged mean daily reflectance loss of 0.0186. The study revealed that while there are periods of intense soiling at this particular site, proper planning of reflector location in relation to the smelter dust sources can significantly mitigate the soiling rate.

Jun 5, 2023

By B. R. Waples

Sometimes a project is born easy, sometimes a project has a hard time being born. Probably every project can say we had tremendous problems to overcome and they would all be right. This project had all things happen to it. Born easy, a hard time after being born, there were tremendous problems to overcome but here it is, a major copper project, a major operation, and a new source of copper for Mexico and the world market. La caridad is an ore body located in the state of Sonora in northwestern Mexico. It is at an elevation of 1,200 meters above sea level and the nearest major city is Hermosillo, the capital city of Sonora. Hermosillo is located approximately 270 kms (about 168 miles) to the southwest of la caridad. North of la caridad, 130 kms (about 81 miles), is the U.S. border town of Douglas, Arizona, which has a sister city on the Mexican side of the border -Agua Prieta.

Jan 1, 1979

By D. D. Bell

This paper presents the history of uranium procurement and demand, and takes a look at future requirements. The three basic conclusions drawn are: (1) the productive capacity of former and existing producers whose operations may be profitably reactivated is insufficient to meet demand projected beyond 1975; (2) reserves in the $5 -$10 price range do not provide the flexibility to sustain production at the high rates required in the late 1970's; and (3) only higher prices can overcome these deficiencies, as this would provide sufficient inducement for the industry to explore for and develop new reserves and productive capacity.

Jan 1, 1967