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In 2007, a total of 725 nonmetal mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Nonmetal mines com-prised 4.9% of all m ining operations. ? Mines producing common clay comprised 25.4% (n=184) of all nonmetal mining operations. ? Nonmetal mining operations were located in all states and territories except Alaska, Delaware, Hawaii, Maine, New Hampshire, Rhode Island, Puerto Rico, and the U.S. Virgin Islands.

Aug 1, 2009

By Frank E. Cash, Max S. Petersen

The use of safe equipment, safeguards, and safe practices in the mining and allied industries should reduce injuries and improve accident experience. The object of this report is to give to the mining industry, especially metal mining, a graphic pictorial description of some of the safeguards, equipment, and practices used and followed in the iron-ore mines of the Lake Superior district. Some of the subject material has been in use or has been established for many years, and some is relatively new. Some of the equipment was purchased commercially, and some was designed by the company employees and constructed in the mine shops. The photographs were taken by the personnel of the Health and Safety Division of the United States Bureau of Mines, primarily for use in the Metal-Mine Accident-Prevention Course of the Bureau of Mines. In general, they are arranged under the following headings or subjects: 1. Accident statistics. 2. Support of ground. 3. Hoisting and haulage. 4. Explosives. 5. Fires, gases, and ventilation.

Oct 1, 1948

By Elaine Cullen, Launa Mallett, Mike Jenkins, C. M. K. Boldt, Thomas Camm

The material in this Information Circular was presented at the National Institute for Occupational Safety and Health’s (NIOSH) open-industry briefing held during the 2004 Northwest Mining Association conference in Spokane, WA. The open-industry briefing discussed results of recently completed and on-going mine safety- and health-related research conducted at NIOSH’s Spokane and Pittsburgh Research Laboratories on the human side of mining—the miner. The first paper sets the stage for what mining has achieved and what we mean by “getting to zero.” The second paper, “Help Experienced Miners Become Great On-the-Job Trainers,” distinguishes between experienced miners and trainers. This paper provides some key concepts for turning great miners into great trainers. “The Power of Story-Telling in Getting Through to Miners” explains the history and importance of stories in the culture and training of miners. Finally, “Understanding Self in Stressful Working Environments,” describes the personal and social aspects of the working environment, much of which parallels familial theories. The downward trend of deaths in U.S. mining has been remarkable. The number of miners killed or injured each year has decreased steadily over the past 100 years. Some charts show these trends overlain with important events such as World War II and the Mine Safety and Health Act. However, this downward trend in mining fatalities has flattened out. How can you get to zero accidents? Do you concentrate on technological advances and equipment maintenance to avoid malfunctions? Do you concentrate on developing work processes and organizational structures that minimize risk? Do you combine them and take a systems approach that links one to the other with an evaluative loop? Safety efforts in mining have used all of these approaches. What more can we do to get to zero? Getting to zero will require two objectives: A clear and unshakeable belief that it can be done and attention to the human side of mining. Getting to zero is not a new idea; it has been used by mine companies and safety professionals for years as the safety goal. But getting to zero is not so much a physical goal as it is a belief that there are no insurmountable barriers to achieving the goal.

Jan 3, 2006

By R. Agarwal

The in-situ stress field was determined, using the overcoring technique, at two underground sites at the Pea Ridge Mine, Sullivan, Missouri. At one of the sites in magnetite, the three dimensional stress field showed the largest principal stress to be compressive (-4564 psi), nearly horizontal and closely parallel to the strike of the orebody. The smallest principal stress was also compressive (-2047 psi) and nearly vertical. Considerable difficulty was experienced in drilling porphyry rock at the second test site in the host rock. Only one hole was drilled at this site. The secondary principal stresses obtained in the porphyry are -9464 and -4945 psi, respectively. The-test site in magnetite is located at a depth of 2505 feet whereas the site in porphyry rock is at 2475 feet. The vertical stresses: due to overburden loading at these sites are -3590 and -2782 psi, respectively. Field determined values of the vertical stress are -2207 and -5098 psi, respectively. The variance; between the two sets of values is most likely attributable to the orebody formation and the differences in the modulii of the host rock and the orebody.

Jan 1, 1977

By Walter K. Utt

The U.S. Bureau of Mines conducted research to develop an accurate, real-time, position monitoring and warning system for the vehicles used in surface mining. The product of this research will be technology to reduce accidents and injuries associated with the operation of surface mining haulage equipment. The position monitoring system should reduce accidents related to vehicle position and also increase the efficiency of haulage operations. This research was conducted in preparation for development of an accurate, real-time position monitoring and warning system, which notifies equipment operators when they deviate from a known safe course and are approaching a fixed hazard. A radar positioning system designed for marine applications was evaluated and a series of tests was run to determine the accuracy of the radar positioning system when used in a land vehicle. The radar position determination was compared to surveyed values. Both static and dynamic (moving vehicle) tests were conducted. The static test results were marginal and the dynamic test results were not accurate enough for the position monitoring and warning system. Although a promising technology, the system tested needs to be modified to meet the accuracy requirements of mobile mine equipment.

Jan 1, 2010

By Arnold F. Stalder

The measurement of various gas concentrations in the atmosphere at a particular location has become a problem of considerable importance. Levels that need to be monitored vary from the range of percent for constituents such as oxygen to parts per million levels for gases like nitrogen dioxide. In particular, mine air can become contaminated with noxious or toxic gases from several sources: fires within the mine, diesel-powered equipment, and explosive sources. The contaminants that result are carbon monoxide (CO), carbon dioxide (CO2), and oxides of nitrogen (NO and NO2). Additionally, oxygen (O2) may be depleted. Thus, the workman can be exposed to potentially toxic or asphyxiating atmospheres. A device was needed that will continuously monitor the mine air in working areas and provide warning of hazardous atmospheres. The Mine Air Monitor was conceived as being a portable, rugged instrument capable of measuring the concentration of the various atmospheric constituents in the mine environment. The unit was to provide both warning signals and quantitative measurements when hazardous contaminants existed at too high a level, or when the oxygen was being depleted. The initial concept involved optical sensors for all of the contaminating gases to be measured, namely CO, CO2, CH4, and NO2, and an electrochemical cell to monitor O2. When the explosion proof requirements of Schedule 2-G made the concept appear to be unfeasible from the standpoint of weight and portability, the program was redirected and a three channel monitor employing electrochemical sensors was adopted. In this case the gases to be monitored were O2, CO and NO2. The remainder of the program was oriented towards obtaining good, commercially available lectrochemical sensors for the above gases, testing them, reducing deficiencies noted during these tests, and making the necessary modifications to integrate the three sensors into a Mine Air Monitor suitable for the mine environment.

Jan 1, 1974

Objective To develop and evaluate the effectiveness of safety training tools specific to underground metal/nonmetal mining. Background In a series of stakeholder meetings held in the western United States beginning in 1998, participants identified a critical lack of appropriate training materials applicable to metal/nonmetal mining. Participants in the meetings provided many insights into what types of training materials are most effective in dealing with both experienced and inexperienced miners. Most important was that the materials should be realistic and interesting and that some way should be found to capture the wisdom and expertise of older miners before they retired. In response, training videos that focus on safe practices during the mining cycle are being produced. Two videos one on handling explosives underground and one on identifying roof hazards and proper scaling techniques were completed during1999, and a third video is now available. This video, entitled “Ground Support...It’s Important, or Miner Mike Saves the Day,” presents information on why ground supports work and how to install them properly. Approach The new video, “Ground Support…It’s Important,” presents a scenario in which two young miners make a bad decision to leave some supports out in order to catch up in their mining cycle. An expert miner, “Miner Mike,” sees this potentially disastrous situation and educates the young miners about what could happen if they continued to leave supports out. He introduces the young miners to several expert miners, who explain how to install different types of supports correctly, as well as share what experience has taught them over the years. How It Works All footage was taken in operating, underground mines, using14 experts to provide the teaching. Because of the wide variety of supports used underground, it was necessary to focus on those types more common to hard-rock mining. While more complex support systems, such as shotcrete and cable bolts, are mentioned, detailed material is not included. In the course of educating young miners Jeff and Jason, Miner Mike provides information on— •Why supports are necessary in underground mines. •The main types of supports commonly used in underground hard-rock mines. •How supports work. •How holes for bolts are drilled correctly using jacklegs, drill jumbos, and bolting jumbos.• How wire mesh, wire panels, metal mats, and different types of bolts, including mechanical bolts, friction bolts, grouted bolts, and cable bolts, are installed properly. •How to recognize that supports have failed and what to do about it.

Jun 1, 2000

By D. Harrington

"There is continued activity in connection with probable reopening of old-time silver producers, but this is largely offset by other obstacles which make metal mining in Colorado a rather precarious proposition. Discussions at the joint meeting of the Colorado chapter of the American Mining Congress and the Colorado Metal Mining Association in Denver, January 20, 21, and 22, brought out many interesting facts, among them that Colorado, once a producer of high-grade ores, and with freight rates, smelting charges, etc. to accommodate high-grade ores, is now compelled to depend almost wholly upon low-grade complex ores or abandon mining, In the face of this, the railroads threaten to advance freight charges, and smelters , because of decreasing tonnage, high labor, etc., must either advance smelting charges or close (the Globe Smelter et Denver recently closed, and it is said that the Salida Smelter will close in February). A serious menace is the possibility of increase of rates by companies supplying electrical power, and the threat of the agricultural interests, now in the saddle in Colorado, to alter the laws so as to greatly increase the burden of taxation to be borne by the mines.In order to stimulate interest in Colorado metal mining, the Colorado Metal Mining Association and Colorado chapter of the American Mining Congress have planned to have an elaborately staged exhibit in the Denver Auditorium during the latter part of the coming summer, This exhibit will reproduce an old time mining camp,including mining structures such as mills, headframes, etc., as well as the camp saloons, dance and gambling halls, etc., together with mineral exhibits from many of the old time mines, no abandoned, but possibly to be reopened. due to increased price of silver, Inasmuch as the Bureau of Mines plans a National First-Aid meet at Denver in August or September, and the Rocky Mountain Mining Institute will also hold its summer meeting in Denver, it seems advisable to hold the three meetings simultaneously and it is proposed to have this done.Labor supply is fairly abundant and apparently not inclined to be dissatisfied; few, if any, strikes or other labor disturbances being found. In some mining regions advances in wages were posted January 1 and no wage reductions are noted.The Rocky Mountain Coal Mining Institute held its meeting at Denver, January 20, 21, and 22, and much attention was devoted to methods of bringing down coal without use of explosives chiefly by undercutting and subsequent use of hydraulic processes of forcing down the coal. Some attention was given the question of labor and it was suggested that the time is at hand when labor unions should be made responsible bodies by incorporation or otherwise. It was agreed to hold the summer meeting in Denver simul-taneously with the holding of the National First-Aid. and Mine Rescue Meet.In general, coal production in Colorado is proceeding satisfactorily with occasional interruption by local strikes, and tonnage is up to that being produced before the strike, but not nearly up to the record of 1918. In general, the labor supply is plentiful, but demand for coal is by no means great and unless some cold weather intervenes, it is probable that the lignite mines will have to go to a three or four day a week basis. There have been no recent disasters, but the Pictou mine of the Colorado Fuel and Iron Company encountered a heavy supply of water, and had to be abandoned until such time as arrangements can be made to pump or bale the water out."

Jan 1, 1920

By D. J. Judy, D. J. Rabovsky, W. H. Pailes, V. Castranova, K. Van Dyke, J. Rabovsky, N. A. Sapola, M. McPeek

"Platelet activating factor (PAF) can be released from pneumocytes following exposure to occupational dust (Am. Rev. Respir. Dis. 135:83, 1987). In addition, PAF has been shown to induce pulmonary inflammation, edema, and bronchoconstriction (Hosp. Prac. 19, 67, 1983). This investigation reports the effects of PAF on the properties of three types of cells found in the lung. PAF (1-100, K1/2 = 2.5 pH) caused depolarization of neutrophils as well as generation of chemiluminescence and secretion of hydrogen peroxide. These responses were dependent on the presence of extracellular sodium. However, PAF did not alter oxygen consumption of neutrophils. Although PAF (10 uM) caused depolarization of alveolar macrophages, no stimulation of chemiluminestence, superoxide secretion, or oxygen consumption was observed. However, PAF (10 uM). did potentiate chemiluminescence and superoxide secretion in response to zymosan (2 mg/ml) by 55% and 36%, respectively. In addition, PAF (10-90 uM) caused aggregation of alveolar macrophages. PAF (2-10 uM) also caused depolarization of type II cells, but did not affect membrane integrity or oxygen consumption. However, PAF (10-18 PM) enhanced the activities of two distinct forms of cytochrome P-450 in type II cells and caused aggregation of type II cells at PAF doses above 18 uM. These data indicate that PAF can affect the secretory activity of pulmonary phagocytes and the ability• of type II cells to detoxify foreign compounds (Bureau of Mines Grant - G1175142).INTRODUCTIONPlatelet activating factor (PAF) is a glycerophospholipid (1-0-alkyl-2-acetylsn-glycerol-3-phosphoryl choline) which has been shown to Mediate a broad range of biological activities (1-3). Its pulmonary actions include contraction of pulmonary tissue (4), secretion of leukotrienes from leukocytes (5), airway constriction (6), pulmonary edema (7), and enhanced migration of neutrophils into the airspaces of the lungs (8,9).PAF can be released from several different cell types, such as, basophils, neutrophils and alveolar macrophages, in response to a variety of particulates or membrane stimulants which include zymosan, calcium ionophore, phorbol esters, chemotactic agents, and endotoxin (10-13). Therefore, PAP may play an important role in the development of pneumoconioses by mediating pulmonary responses of lung cells to a variety of occupational dusts. To investigate this possibility, we determined the effects of PAF on several physiological parameters of neutrophils, alveolar macrophages, and alveolar type II epithelial cells."

Jan 1, 1988

By D. J. Bauer

A primary amine extraction system was investigated for fractionating a cerium-group, lanthanide sulfate mixture. Addition of diethylenetriaminepenta-acetic acid (DTPA) to the amine extraction system resulted in separation factors as high as 5.4 for lanthanum-cerium, 8.0 for cerium-praseodymium, 3.7 for praseodymium-neodymium, and 7.0 for neodymium-samarium. In multistage studies on a cerium-free lanthanide mixture, 96 percent of the lanthanum was recovered with a purity of 95 percent.

Jan 1, 1968

By Ludwig Schmidt

Investigations conducted by the Bureau of Dines pertaining to the reduction of evaporation losses of petroleum have shown that such losses may be reduced 70 to 80 per cent by the use of vapor-tight tanks equipped with vacuum and pressure relief valves, and vapor-tight thief hitches. Additional studies have shown that it is often economical to supplement this type of construction with other measures that will reduce evaporation losses still further. Water-cooling systems, insulation, and light colored paints are the measures most often used in connection with vapor-tight tanks. Painting with light colored paints probably is employed in the greater number of cases. On account of the cost of insulation, or of installing water cooling systems, the use of these methods are restricted to tanks containing gasoline or crude petroleum with a very large content of low-boiling fractions. The effect of cooling systems has been discussed in a previous report.2 In choosing paints for tanks many factors must be considered. Probably the three most important are cost, protective value, and color. Many companies have adopted a standard color for all of their tanks in this way they reduce the initial cost of paint by buying in large quantities. The tank farms of such companies usually have a neat appearance, resulting from the uniform painting of all tanks. This procedure also has advertising value. Unfortunately, most of the paints used to protect steel are of the darker colors, usually red or black. These colors accelerate the rate of evaporation. Several companies have solved this difficulty by using a dark colored metal-protective paint as a primer coat, and a paint of any desired color for the final coat. Special metal-protective primers to be used under light-colored cover coats have been placed on the market by several paint manufacturing companies.

Jan 1, 1925

By Bernard Porter

Differential thermal analysis measurements were used to characterize a phase diagram for the KF-YF3 system at compositions between 0 and 60 mole-percent YF3, A congruent melting point compound was observed at 3KF?YFs, which melts at 965°±5° C and undergoes solid-state decomposition at 725°±2° C. One peritectic and two eutectic compositions are also defined.

Jan 1, 1969

By Robert H. Peters

This report presents findings from a Bureau of Mines study on barriers that may prevent miners from correcting and avoiding groundfall hazards. Such barriers stem from four basic types of problems: (1) inability to recognize groundfall hazards, (2) inability to correct groundfall hazards, (3) lack of motivation to search for groundfall hazards, and (4) lack of motivation to correct groundfall hazards. Data are presented that summarize the views of miners, section supervisors, and mine inspectors about the contribution of these barriers to groundfall accidents and what they think should be done to reduce the frequency of injuries sustained by falls of roof and rib. The report also includes a summary of miners' responses concerning their recent experiences with groundfall accidents, along with industrywide statistics on accidents and injuries caused by ground falls in underground coal mines.

Jan 1, 1987

By Spencer P. Howell

One of the important problems in metal mining , tunneling or quarrying is the most economical method of bringing down the ore or rock . The two factors having great influence in determining this are arilling and blasting costs . In considering the efficiency of the explosive used , the diameter of cartridge has always been supposed to play an important part . However , the Bureau's attention has been called to the lack of definite data on the effect of cartridge diameter on the strength and sensitiveness of high explosives . This information is especially valuable to the user of explosives as it assists him to determine what diameter of borehole is most economical . A paper* on "The effect of cartridge diameter on the strength and quickness of high explosives " was submitted to the sub- committee on Drills and Drill Steel of the 24th Annual Convention of the American Mining Congress by Charles S. Hurter , Technical Representative of the E. I. duPont deNemours and Co. In this paper Mr. Hurter points out that the physical characteristics of an explosive most affected by the diameter of cartridge are rate of detonation and sensitiveness to explosion by influence , and that both increase with increase in diameter . As there is a continuing tendency to the use of smaller diameter drill holes in order to lower drilling costs , and as the smaller drill hole requires a smaller diameter of explosive cartridge than larger drill holes do , this paper has been prepared to show the effect the diameter of cartridge will have on the strength and sensitiveness of the high explosives which may be used . Accordingly , the Bureau of Mines , in cooperation with the Institute of Makers of Explosives , has carried out a series of tests to show the effect of cartridge diameter on the strength and sensitiveness of certain high explosives .

Jan 1, 1923

By Phillip Allender, Wolf Karo, Knox Van Dyke, Lixin Wu, Ali Ardekani, Jorge Garcia, Jaime Gutierrez

"We report that two different micropolystyrene round beads linked to either luminol or lucigenin have been developed. The 1-µ.m-diameter beads arc useful reagents that allow one to perform chemiluminescent (light producing) phagoeytic reactions without opsonization. It is known that luminol reacts with peroxidases (e.g., myeloperoxidase) while lucigenin reacts mainly with superoxide anion. Luminol and lucigenin beads produce cellular chemiluminescence (CL) with neutrophils, macrophages, monocytes, and differentiated human promyelocytic leukemic cells (HL60). When myeloperoxidase (MPO) is present luminol beads evoke higher CL from neutrophils, but when little or no MPO is present, lucigenin beads produce higher amounts of light. Lucigenin beads appear to be active inside these cells where unbound lucigenin does not enter freely.INTRODUCTIONA variety of cells, e.g., neutrophils (Ns) and macrophages (Ms), can engulf foreign particles (1). This engulfing or phagocytic activity is used by the body to kill bacteria and to eliminate foreign particles such as respirable dusts, e.g., coal, silica, or cotton. The neutrophil engulfs or phagocytizes bacteria which are coated with plasma antibodies and/or complement proteins (Fig. 1). The coating or opsonization allows the neutrophil to recognize foreign substances. Usually the absence of opsonization prevents the cell's recognition of a foreign particle and the particle is not phagocytized. Macrophages, particularly the alveolar Oung) cells, do not require opsonization for phagocytosis. Ms should not be selective toward individual dusts because they serve a major role in eliminating a variety of these.Particle size can also be a factor. Usually a particle with a diameter of 0.5-5 µ.m is considered in the respirable range. Larger particles are trapped before they reach the alveoli Oung spaces where oxygen exchange with blood occurs), ·and smaller particles do not generally settle, and are not engulfed by macrophages (2). Tabato and Ikada (3) found that maximal phagocytosis of microspheres takes place when their diameter is in the range of 1.0 to 2.0 µ.m. In addition, they found that beads with hydrophobic surfaces were more readily phagocytized than hydrophilic surfaces."

Jan 1, 1990

By ALICE V. Petar

Thallium is one of the rare metals that has come into commercial use within recent years . Its comparative scarcity , combined with a resemblance to the common metal lead , have retarded the development of uses for thallium . Although production is still measured in pounds rather than in tons , it is now finding application in a number of fields . Perhaps the earliest commercial use of thallium was as a constituent of optical glass of higher refractive power than similar glasses containing lead . One of the later applications to attract attention was the use of the oxysulphide in a sensitive electrical device similar to the selenium cell . The " Thalofide " cell , which was patented in 1919 , constituted for a time the most important outlet for thallium. During the next few years the limited use of thallium and its salts in other fields was insufficient to absorb an annual production of a few hundred pounds , and the price dropped from $ 16 or $18 per pound in 1922 to $ 5 per pound in 1924 . Beginning in 1925 several new uses were developed , especially as a poison for rodents and ants , and as a result the demand for thallium increased sufficiently to cause a recovery in price to the present level of from $12 to $15 per pound .

Jun 1, 1931

By G. S. Rice, R. V. Wheeler

"FOREWORDThe cooperative mine safety research program was carried on successfully in the year 1930 in a manner similar to that described in the report for 1929It is believed that the results of such fundamental work as is being done are unquestionably of great benefit in their application in coal-mining operations, in the saving of life and health of minera. The research result compared and checked by investigations in the two organizations, and further by large-scale tests, as in the Experimental Mine, give confidence to mine operators, miners and State mining officials in the findings of the various researches.The annual report of the contact officers of the United. States Bureau of Mines and the British Safety in Mines Research Board to the Director of the Bureau and the Chairman of the Board respectively, follows:Annual Reports for 1930 To: The Director, Bureau of Mines.The Chairman, Safety in Mines Research Board."

Sep 1, 1931

By Mah Alla D.

Previously existing heat-of-formation values for the oxides of vanadium were rudimentary. They were subject to uncertainties of 1 to 5 kilocalories per gram-atom of contained oxygen. This fact has been the only adverse influence on the accuracy of thermodynamic calculations involving these substances, as the requisite entropy and high-temperature heat-content data are known with reasonable accuracy. This report presents new heat-of-formation data for four oxides of vanadium (VO, V203, V02, and V205), obtained by combustion calorimetry. It is believed that the uncertainties have been reduced to 0.1 to 0.3 kilocalorie per gram-atom of contained oxygen. The new heat-of-formation data were combined with existing entropy and high-temperature heat-content values to obtain free energies of formation of the four oxides at temperatures up to 2,000° K.

Jan 1, 1961

By John C. Edwards

Carbon monoxide (CO) sensors are used in mine fire early-warning systems. Experiments were conducted by the U.S. Bureau of Mines with six diffusion-type CO sensors to determine their response to a reference CO concentration under both static and dynamic flow conditions. Static experiments were conducted with 0.5 L/min flow of 16 ppm CO in N2 through 8-and 12-L chambers. Dynamic flow experiments were conducted in two environmental chambers: One had directional flow capability of 1 m/s, and the second provided moderately nondirectional flow as high as 1.8 m/s. Reference CO concentrations of 13.5 to 19 ppm in air were used for the dynamic experiments. The results of the static experiments demonstrated that the sensors consistently underestimated the reference gas concentration. The dynamic experiment results showed the sensors provided reasonable agreement with the reference gas concentration when directional flow effects were not considered. Directional flow effects were evaluated for two sensors. One of the sensors showed a strong dependence upon the relative orientation of the diffusion tube with respect to flow direction. The second sensor did not show a dependence upon flow direction. The sensors' directional flow effect is significant for their proper in-mine utilization.

Jan 1, 2010

By John E. Hamak

The U.S. Bureau of Mines estimates the identified helium resources of the United States at 630 Bcf as of December 31, 1990. This includes 295 Bcf of demonstrated reserves, 87 Bcf of demonstrated marginal reserves, and 42 Bcf of demonstrated subeconomic resources. The identified resources include 161 Bcf of helium in inferred and marginal reserves and 45 Bcf in inferred subeconomic resources. The identified helium resources contained on Federal lands are approximately 170 Bcf, including 32 Bcf in underground storage in the Cliffside Gasfield near Amarillo, TX. In addition to the identified helium resources, undiscovered helium resources in the United States are estimated at a most likely volume of 103 Bcf, with a maximum volume of 259 Bcf and a minimum volume of 41 Bcf. Also reported are 43 Bcf of helium in nonconventional and low-helium-content natural gases. Current extraction of helium in the United States occurs mostly from natural gases produced from the Hugoton gas area in Kansas, Oklahoma, and Texas, and the Riley Ridge area in southwest Wyoming. Helium extracted from natural gas in the United States in 1990 was 2.5 Bef. If current trends continue, some shortfalls in helium supply may occur in about 5 to 10 years.

Jan 1, 1993