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By Dana C. Reinke, David K. I Ingram

Researchers at the National Institute for Occupational Safety and Health partnered with the water well industry to develop engi­neering control technologies and training products to address noise exposure at the job site. Noise­induced hearing loss continues to be a problem in the well drilling industry. Research con­ducted by NIOSH found that air rotary drill rigs produce sound levels more than 90 dB(A) over the course of an eight­hour workday. Sounds levels above 90 dB(A), identified during hammer drilling and the hammering of casing, exposes workers to levels that can damage hearing. A typical air rotary drill rig provides no barrier, for noise and dust pro­tection, between the drill’s control panel and the drill stem. The development of a partial cab is the clearest example of NIOSH’s research partnership with the water well industry. NIOSH researchers determined that an engineering noise control to protect the oper­ator at the rig’s control panel would be effective, based on typical work site conditions. Many surface rigs do not have full cabs as a result of the original equipment manufacturer design or the high cost of aftermarket products. Developed as a partial cab, the NIOSH engineer­ing noise control design addressed stakeholders’ needs associated with cost, transport, and worker usage (Figure 1). Field tests found the partial cab effective in reducing sound levels at the rig’s control panel, a typical location for a drill rig operator. Sound levels at the control panel were reduced from 104 to 96 dB(A) (Figure 2). Coupled with continued use of personal protective equipment, such as hear­ing protection devices, the partial cab can help to reduce noise exposure. NIOSH researchers created a CD with informa­tion about noise exposure and the partial cab. Most important to well drilling companies is information on how to construct and attach the partial cab to drill rigs. The CD can be viewed on a standard computer and includes a video of the partial cab in use on a work site. Computer­aided design drawings are included on the CD and provide detail of the cab design as well as information on construction mate­rials and design details. Additionally, the CD provides background infor­mation on noise­induced hearing loss and hearing protection devices to increase knowledge about this occupational health concern. This information can be viewed by all company employees to help promote the partial cab’s importance to workers using the cab. More information on the partial cab noise control technology can be downloaded from www.cdc.gov/ niosh/mining NIOSH researchers also examined the health and safety training needs of workers in the ground water industry. It was quickly realized that most workers learn health and safety on the job and do not attend any sort of formal training. In addition, there is not a lot of time for daily “tailgate talks” or “shop talks” on health and safety issues. As a small business industry, the owner is often operating a drill rig along with his other employees. In general, new employees learn the job in an apprentice style sys­tem. As a result, workers and owners have few opportunities to access uniform health and safety information based upon the job — an outdoor work environment with daily change in work sites. With this information, NIOSH researchers devel­oped two products that deliver health and safety information to fit into the daily work of well drillers. Both are information circulars and are available through download at www.cdc.gov/niosh/mining and the NGWA Web site at www.ngwa.org/publication/ publications.cfm. These circulars are: Water Well Safety Bits. This booklet provides information in a “quick bites” style. It is pre­sented in a magazine format and can be left on

By Galen H. Clevenger

Although there are exceptions, oxidized silver ores containing the higher oxides of manganese are generally refractory to hydrometallurgical methods of treatment. When these ores are of high enough grade they can be smelted; indeed, some rather low-grade ores of this type have been smelted at a profit because of their fluxing value. In the past, when these ores could not be smelted, they either were not treated or were treated at low efficiency, generally by cyanidation. The need for thorough investigation of the problem was therefore evident for some time before the writers began their research. The problem of treating manganese-silver ores seems to have been recognized first about 35 years ago by C. W. Goodale in applying pan amalgamation at Tombstone, Ariz. He attributed the low extraction of silver to the fouling of the mercury by manganese rather than to the presence of a refractory compound of manganese and silver. Although definite knowledge as to the cause of the poor extraction of silver was lacking, a more or less effective preliminary treatment, that is, a chloridizing roast, was applied.

Jan 1, 1925

By R. A. Franks, G. F. Friel, J. C. Edwards, L. Yuan

Five mine fire experiments were conducted in a 2.08m high and 2.90m wide, ventilated mine entry in the National Institute for Occupational Safety and Health (NIOSH)'s Safety Research Coal Mine (SRCM) to determine the effect of the dispersion of carbon monoxide (CO) on mine fire detection. CO measurements were made at distances from 7.6 m to 45.2 m downwind from the fire with diffusion mode CO sensors positioned near the roof. For small intensity fires, less than 30 kW heat release rate, generated by 14 kg coal in a 0.61 m square tray, it was determined that air flow and sensor spacing were significant for fire detection at the 10 ppm CO alarm level. Within 15.0 m downwind distance from the fire, 10 ppm CO alarm values occurred for volumetric air flows less than 11.5 m3/s. However, the 10 ppm CO alarm value did not occur 30.0 m downwind from the fire for air quantities greater than 6.2 m3/s due to dilutive mixing of the CO in the air stream. The criterion that the mine fire alarms occur within 15 min of the onset of flaming combustion could not be consistently met with the 10 ppm CO alarm. This suggests the use of lower CO alarm values, or reduced CO sensor spacings for mine fire protection. It is demonstrated how computational fluid dynamics (CFD) can be used to model the CO dispersion downwind from the fire in support of a plan to optimize sensor spacings.

By Clive Ellis, Brian Davies, Steven E. Mischler, Jon C. Volkwein

A primary means to reduce environmental levels of diesel particulate matter (DPM) exposure to miners is to reduce the amount of DPM emission from the engine. A quick and economic method to estimate engine particulate emission levels has been developed. The method relies on the measurement of pressure increase across a ?lter element that is brie?y used to collect a DPM sample directly from the engine exhaust. The method has been re?ned with the inclusion of an annular aqueous denuder to the tube which permits dry ?lter samples to be obtained without addition of dilution air. Tailpipe ?lter samples may then be directly collected in hot and water-supersaturated exhaust gas ?ows from water bath-cooled coal mine engines without the need for dilution air. A primary means to reduce environmental levels of diesel particulate matter (DPM) exposure to miners is to reduce the amount of DPM emission from the engine. A quick and economic method to estimate engine particulate emission levels has been developed. The method relies on the measurement of pressure increase across a ?lter element that is brie?y used to collect a DPM sample directly from the engine exhaust. The method has been re?ned with the inclu­sion of an annular aqueous denuder to the tube which permits dry ?lter samples to be obtained without addition of dilution air. Tailpipe ?lter samples may then be directly collected in hot and water-supersaturated exhaust gas ?ows from water bath-cooled coal mine engines without the need for dilution air.

By Lewis C. Karrick, Martin J. Gavin

"Introduction.The theory of fractional ""education"" of oil from oil shale has been used by several inventors as the basis for the design of retorts for the production of oil from the oil shales of the United States. The term fractional ""education"" gives expression to the rather common belief that when an oil shales is heated it produces light, low-boiling oils as low temperatures, and increasingly heavier, higher-boiling oils as the temperature of retort¬ing rises. The theory evidently had its origin in the fact that crude petroleum may be fractionally distilled, yielding light oils at low distillation temperatures, and heavier oils as the distillation temperature increases is as, gasoline is produced from petroleum at relatively low temperatures, kerosene at higher temperature, and heavier products such as gas-oil and lubricating distillation at still higher temperatures.The writers have examined several oil-shale retorts designed to take advantage of the belief that crude, and in some cases refined, gasoline can be recovered from the shale at low temperatures; kerosene at higher temperat.res, and so on. Such retorts are usually designed to operate continuously and have several vapor-pipes lending from them at differing intervals and passing to separate condensers. Designers of such retorts repeat that the distillate from the low-temperature parts of the retort will be gasoline, and that as the shale passes to zones of increasingly higher temperatures, the vapor lines lending from these zones rill remove increasingly heavier products such as kerosene, gas-oil etc."

Mar 1, 1924

By Elaine T. Cullen

Miners, like many skilled blue-collar workers, are not traditional learners. They have not always been successful in classroom-type settings, preferring to learn on the job in a hands-on environment. U.S. law requires that miners have a minimum of 8 hours of safety training annually, plus 40 hours for underground miners and 24 hours for surface miners when they enter the industry. However, miners rarely view this training time positively. In fact, it has been called “safety jail” by many, who regard it as a time to get a little extra sleep While mining has become far safer in the past 100 years, it is still a dangerous occupation. The Office for Mine Safety and Health Research, a part of the National Institute for Occupational Safety and Health (NIOSH), has funded a project for the past 4 years to address this challenge. The purpose of the research was to find a way to develop effective safety training for these people. Miners are born story tellers. They share “near miss” stories, stories about master miners they have known, and stories about how things used to be. These stories not only pass along information about what will happen if a miner fails to respect the mining environment, they also instruct listeners in the culture of mining and the values that it embraces. Stories, it seems, are a way to get safety messages across to miners, especially inexperienced ones, and using older, wiser miners in these stories is an obvious choice. This paper will discuss how a series of training videos was developed, how “master miners” and story lines were chosen, and how the resulting videos have been received in the mining industry.

By Eric S. Weiss, Deno M. Pappas, Timothy M. Barton

During the past few years, the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) has been evaluating developments with surface support liners which includes shotcrete and thin spray-on liners (also referred to as sealants, coatings and membranes) from a ground control perspective. The proper selection and use of a surface support material can significantly enhance ground control which may result in a decrease in worker related injuries due to ground falls. The purpose of this paper is to evaluate the preliminary findings of a long-term underground study of various types of surface support liners, and to examine installation practices that are critical for an effective liner material application. The underground study utilizes NIOSH’s Lake Lynn Laboratory Experimental Mine to evaluate the long-term performance of several types of shotcrete and thin spray-on liner materials. Liner material performance to date was evaluated on a regular basis over a three year period. Although the study is still ongoing, critical mining practices were identified that may seriously affect the bond of the liner material to the mine roof and rib.

By Paul L. Michael

This report presents a discussion of perforance parameters for electronic or active hearing protectors that will meet the needs of underground coal miners. This information is incorporated into a proposed set of specifications that can be used to judge the suitability of a particular electronic hearing protector for the coal mine application. Acoustic and electrical tests were performed on a developmental model of an electronic hearing protector built by the U. S. Bureau of Mines. This model showed only a slight reduction in speech intelligibility which was traced to poorly matched components and in particular to the transducers. Tests of alternative components showed the Knowles BL-1671 microphone to be suitable for this application because of its performance and extremely small size. The Roan-well H-143/AIC earphone was found to have a good frequency response but has the disadvantage of being rather bulky which causes a slight degradation of a low frequency attenuation of the hearing protector. A satisfactory installation of these components in a hearing protector muff was demonstrated and tested. Results of tests of several methods of controlling the sound level under the hearing protector muff showed that a simple diode clipper circuit can be used with only a negligible loss in speech intelligibility for normal-hearing listeners. A commercially available active hearing protector, the British-built ACOS A-9000/2 was examined. This hearing protector provides sound level limiting through a saturating amplifier. Preliminary tests have shown that the performance characteristics of this commercial unit meet many of the proposed specifications so further testing and evaluation should be performed to determine its suitability for use 1n underground coal mines. The recommended test of intelligibility for electronic hearing protectors and other communication systems as used in a coal mine setting is the Modified Rhyme Test (MRT) developed by House et al. in 1965. The suitability and method of administering this test are discussed.

Jan 1, 1976

By Frank E. Chase, John L. Ellenberger, Christopher Mark

The nature of competition in the coal market tends to deplete the most favorable coal reserves first, and forces subsequent development of mines in more extreme ground conditions such as those associated with multiple-seam mining. In fact, 70% of the United States coal reserves are in multiple-seam situations. The National Institute for Occupational Safety and Health (NIOSH) is conducting research to develop mine design algorithms that will result in safer multiple seam mines. This paper presents an overview of multiple seam issues in the central Appalachian coalfields. To date, more than 50 case histories have been analyzed from 20 operating mines in Eastern KY, Western VA, and Southern WV. Each case history is classified according to the degree of multiple-seam interaction, ranging from no apparent interaction to severe interaction with direct impacts on mine safety and resource recovery. The case histories are also examined with regard to amount and geologic characteristics of interburden and overburden, and design stability factors. The sequence of mining has also been found to be critical when the lower seam is fully-extracted. This paper compares current case histories to traditional rules of thumb. In addition two situations were modeled using LaModel software. LaModel has been upgraded to import pillar grids and topographic data from AutoCAD files. The cases presented demonstrate vertical stress capabilities of LaModel.

By Peter Swanson

One of the primary methods for analyzing roof stability in underground mines is the age-old method of “roof sounding” where a miner taps on the roof and listens for the hollow sound of loose blocks of rock. This paper looks at the feasibility of using noncontact laser-based vibration measurements to detect roof fall hazards with the ultimate vision of improving, expanding and automating procedures for mine roof inspection. Vibration measurements made on loose blocks of rock in underground mines are summarized and compared to estimates of fundamental resonance frequencies for rock slabs of the size responsible for highly hazardous “skin failures.” Both laser Doppler vibrometry and full-field interferometric methods are examined and are considered to be feasible methods for detecting anomalous vibrations in loose roof rocks. Results from simple laboratory experiments using laser vibrometry demonstrate some of the proposed application concepts. While considered a challenge to move these techniques from the laboratory to heavy industrial or outdoor environments, the potential for success in the current application is enhanced by the reduced requirements of qualitative analyses.

The Bibliographic Data Base is the result of a literature search con-ducted as one task of the technology assessment of current and advanced logging techniques, sponsored by the United States Bureau of Mines. After compilation, the bibliography was converted to an automated form for ease of utilization, and to allow for maintaining and updating the data base. The data base covers articles, symposia, books, patents, corporate and government reports, and other literature concerned with some aspect of borehole logging from January 1969 through December 1975. Periodic up-dating will be necessary to keep the data base contents in step with developments in the rapidly advancing field of application of borehole logging to mining. Many bibliographic indexes were scanned for entries relating to the subject of interest, and those entries which were included in our data base contain a reference to the bibliographic index in which they were listed (see Section 2.4.7). With the aid of these indexes, a vast number of publications, including foreign reports and publications, have been scanned for works relevant to borehole logging technology.

Jan 1, 1976

By Joel N. Van Sant

An investigation was conducted to study possible sources of Utah refractory and structural clays that could be used for the manufacture of refractories and light or buff burning heavy-clay products. A field study was made and the clay samples tested to determine their firing characteristics. Results of the Bureau's work indicate many small noncommercial deposits of hypogenic clay occur in igneous rocks. Commercial hypogenic deposits are mostly halloysite clay developed by hydrothermal replacement of limestone. The high firing shrinkage of halloysite precludes its use as a refractory, however, halloysite produced at the Dragon Mine south of Eureka, is used fur making oil catalysts. Clays and shales suitable for low heat duty refractory products are found in the Manning Canyon shale, in shales associated with coal bearing rocks, and in the Dakota formation. Some of the clays from the Dakota formation are also suitable for high-duty refractory products.

Jan 1, 1964

By O. W. Owings

"The handling and transportation of explosives and explosives supplies are inherently hazardous owing to their sensitiveness to impact and flame or electric arcs and sparks. Many accidents have occurred in the past during transportation of explosives, especially when they were carried by individual miners on man-trips. When electric haulage became the usual mode of transportation and shots were fired electrically, the hazards of carrying explosives and supplies on man-trips were fully realized, and in some mines all explosives were placed in one car, usually at the rear of the trip. Far-sighted managers saw the danger of this practice and provided separate trips for delivering explosives. This step was a definite advance in safety, but the latest achievement is the construction of special, rugged, nonconducting cars.Many coal-mining men have shown considerable interest in the construction of safe cars for explosives during recent months. Undoubtedly many others are interested in this phase of safety, therefore this circular is issued to give information on cars of this type now in use.Car A (fig. 1) is essentially a closed inner box separated from an outer box by an insulating lining of rubber. The double box is attached to a standard steel chassis that has spring journals and electric welding instead of certain rivets. The chassis is equipped with roller bearings. The over-all length from pin to pin is 11 feet, 9 inches; the wheel base is 54 inches, the track gage 42 inches, and the capacity eighteen 50-pound cases of permissible explosives. The box is 10 feet long, 6 feet wide, 3 feet high at the top of the arched roof, and 2 feet 9 inches at the edges. The top of the car is 46 inches above the top of the rail.The inner box is insulated from the outer box by two pieces of 1/4-inch switchboard.-insulating matting cemented together. To cover the top, two ends, two sides, and the bottom of the box requires 320 square feet of the l/4- inch matting.The walls are well-seasoned tongue-and-groove oak, 1 1/4 inches thick and 2 3/4 inches wide. A 1 1/4-inch air space is maintained by oak strips between the outer wall and the two thicknesses of 1/4-inch rubber matting. The inner box is made of 7/8-inch, well-seasoned, tongue-and groove oak fitted closely against the insulating matting. No nail, rivet, or bolt extends through the rubber insulation.The floor of the outer box is secured to the chassis by two sets of bolts through an intermediate piece of well-seasoned oak. One set of bolts is countersunk from the top of the intermediate piece of oak, and the other set is countersunk from the bottom. The countersunk portions are filled with ""insulate,"" an insulating compound. Adjacent bolts are at least 6 inches apart.The bed of the inner box is divided into six compartments by transverse strips of wood at the bottom and partitions near the roof. Each compartment accommodates three 50-pound cases of explosives. This arrangement prevents cases in adjacent compartments from touching, so that there is no possibility of end thrust of the entire load of explosives. Each inner compartment is 21 inches high, 5g inches long, and 16 1/4 inches wide. Separating strips at the floor are 3 inches wide and 1 1/4 inches thick. The outside dimensions of the 50-pound cases of explosives used are 17 1/2 inches long, 13 1/2 inches wide, and 12 1/2 inches high."

May 1, 1940

By Steven J. Knoll, Theodore J. Williams, Douglas F. Scott

Highly stressed rock in stopes continues to be a primary safety risk for miners in underground mines because it can result in failures of ground that lead to both injuries and death. Spokane Research Laboratory personnel investigated electromagnetic (EM) emissions in a deep underground mine in an effort to determine if these emissions could be used as indicators of impending catastrophic ground failure. Results suggest that (1) there is no increase in the number of EM emissions prior to recorded seismic activity, (2) some EM signals are generated during blasting, (3) interference from mine electrical sources mask seismic-generated EM signals, (4) EM emissions do not give enough warning (compared to seismic monitoring) to permit miners to leave a stope, (5) the distance an EM signal can travel in the rock is between 18 and 40 m, and (6) current data acquisition systems do not differentiate between EM signals generated from seismic activity and random mine electrical noise. These results preclude monitoring EM emissions as precursors of impending catastrophic ground failure.

By George W. Toth

Uranium in situ leach mining has recently emerged as a viable alternative to conventional miring techniques. The cost implications of in situ mining are therefore of increasing interest to mining paracticioners as well as public officials. This report presents the results of an assessment of uranium in situ leach mining costs through the application of process engineering and discounted cash flow analysis procedures. A computerized wasting technique, termed a cost model, was developed through this effort to facilitate rapid cost analyses. Application of this cost model will generate mine life capital and operating costs as well as solve for economic production cost/lb. U308. Conversely rate of return may be determined subject to a known selling price. The data bases of the cost made! have been designed to reflect variations in Texas vs. Wyoming site applications. The results If applying the model under numerous ore deposit, operating, wellfield and extraction plant conditions for Texas and Wyoming are summarized in the report. Sensitivity analysis of changes in key project parameters have also been tested and reported.

Jan 1, 1981

By K. C. Dean

Changes in the types of materials used for the construction of recent automobile models have occasioned a review of the continued applicability of current recycling techniques. Plastics are being used increasingly in late model cars. To evaluate the changes occurring, a 1972 Mercury Montego, furnished by the Ford Motor Co., was completely dismantled and analyzed, and the composition was compared with that of a composite automobile from 15 vehicles ranging in date of manufacture from 1954 to 1965 and designated as a circa 1960 model. The composite vehicle contained about 26 pounds of plastics, while the 1972 model contained over four times that quantity. The increasing use of plastics in automobiles suggests that research to improve the economic potentiality of plastics recycling is warranted.

Jan 1, 1974

By Gustav Wafe

"INTRODUCTION The discovery in 1901 of ""gusher"" oil production at Spindletop, Tex., Tex., a salt-dome structure, led to exploratory drilling on other known domes and known domes and in areas contiguous to salt domes in the Gulf Coast region of Texas and Louisiana. Early drilling on the flanks of the domal structures disclosed incompetent 3/ shales, which flowed into the hole when attempts were made to drill through them. Often these shales seized the drill pipes and presented with equipment then in use, an insuperable barrier to deeper drilling. The obstructing incompetent shales came to be called ""heaving"" shales by drillers who attempted to drill through them. Formations of this type have hampered the penetration of the drill bit in many area in the Gulf Coast region to such an extent that the drilling of wells through heaving shale has become a major problem."

Mar 1, 1942

Mercury has been used by mankind since prehistoric times. It has been, and is now, widely used in industry and medicine and has unique properties which make direct substitution difficult or impossible. At present its principal uses are for electrical apparatus, control instruments, electrolytic soda preparation, mildew-proofing paints, pesticides, and medical and dental preparations. Deposits of mercury are less common than those of other base and precious metals, but some of the deposits are very large and have been ample to meet the world's past demands. The price of mercury has had many sharp fluctuations, but in general, the limited number of producers has resulted in a more stable price structure than that of many other commodities. The United States has been one of the main producers of mercury, and from 1850 to 1961 produced 3,247,704 flasks. Yearly production since World War I1 has varied from 4,535 to 38,067 flasks. An estimate of domestic resources of mercury producible at various price ranges was prepared for each mercury mine by combining specific knowledge of mercury mineralization with estimates of potential, based on geologic information and past production history. The sum of the individual estimates for each price range is shown in a table. A parallel estimate of nationwide production potential was made from a study of past price and production relationships. These were analyzed by plotting yearly production figures against the previous year's price, expressed in dollars of constant purchasing power. An equation was fitted to the data by mathematical means and was used to extend the curve into areas of higher than historic prices. Potential production rates at various price levels were taken from this graph. The estimated yearly production rates were used to make an estimate of total potential based on the premise that production rates and reserves have a proportionate relationship. The rate of developing mercury reserves during the period from January 1944 to January 1962 is considered, and it is shown that if this rate can be continued, the mercury resources of the United States, at a constant dollar price of $500 per flask, are adequate to support a production of 60,000 flasks per year for 30 or more years. This publication contains a history and description of the mercury industry in every State which has had production and individual descriptions of all mercury properties which have reported significant production. Accompanying tables give the important facts about all known mercury occurrences.

Jan 1, 1965

Mercury has been used by mankind since prehistoric times. It has been, and is now, widely used in industry and medicine and has unique properties which make direct substitution difficult or impossible. At present its principal uses are for electrical apparatus, control instruments, electrolytic soda preparation, mildew-proofing paints, pesticides, and medical and dental preparations. Deposits of mercury are less common than those of other base and precious metals, but some of the deposits are very large and have been ample to meet the world's past demands. The price of mercury has had many sharp fluctuations, but in general, the limited number of producers has resulted in a more stable price structure than that of many other commodities. The United States has been one of the main producers of mercury, and from 1850 to 1961 produced 3,247,704 flasks. Yearly production since World War II has varied from 4,535 to 38,067 flasks. An estimate of domestic resources of mercury producible at various price ranges was prepared for each mercury mine by combining specific knowledge of mercury mineralization with estimates of potential, based on geologic information and past production history. The sum of the individual estimates for each price range is shown in a table. A parallel estimate of nationwide production potential was made from a study of past price and production relationships. These were analyzed by plotting yearly production figures against the previous year's price, expressed in dollars of constant purchasing power. An equation was fitted to the data by mathematical means and was used to extend the curve into areas of higher than historic prices. Potential production rates at various price levels were taken from this graph. The estimated yearly production rates were used to make an estimate of total potential based on the premise that production rates and reserves have a proportionate relationship. The rate of developing mercury reserves during the period from January 1944 to January 1962 is considered, and it is shown that if this rate can be continued, the mercury resources of the United States, at a constant dollar price of $500 per flask, are adequate to support a production of 60,000 flasks per year for 30 or more years. This publication contains a history and description of the mercury industry in every State which has had production and individual descriptions of all mercury properties which have reported significant production. Accompanying tables give the important facts about all known mercury occurrences.

Jan 1, 1965

By Travis Q. Lyday

During 1981, Ecuador's gross domestic product (GDP) increased by a reported 4.8% in real terms, a slight improvement over that of 1980. In current prices, the CDP in 1981 was estimated at $13.7 billion.2 The inflation rate increased to 15.6% according to official figures, above that of 1980. Ecuador's production of petroleum increased 3% in 1981 compared with that of 1980. The consortium of Corporación Estat al Petrolera Ecuatoriana (CEPE), the state oil company, and Texaco, Inc., produced almost 98% of the total from their Putumayo Basin operations in Oriente, the eastern jungle region. In sharp contrast, output from the Santa Elena Peninsula Fields, where oil was first produced commercially in 1921, continued to decline, producing only 510,000 barrels, a decrease of almost 8% compared with that of 1980.

Jan 1, 1983