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By T. F. Mitchell, J. A. McAllister, S. J. Hussey

"INTRODUCTION During the Bureau's extensive program of investigating possible domestic sources of manganese, an are-dressing study was conducted in its laboratories at Salt Lake City, Utah, on a sample of oxide manganese ore representative of vein material from the Ophir Hill mine at Ophir, Tooele County, Utah. The sample (obtained by blasting down and mixing a portion of the vein) was submitted by the Ophir Development Co. of Ophir, Utah. As the ore was too law in grade to be acceptable for direct production of ferromanganese, it was tested to determine its amenability to concentration by ore-dressing methods.At the beginning of the investigation of manganese-ore beneficiation in December 1940, the only product marketable to Metals Reserve Company was ferrograde manganese, grade B, the requirements for which follow: Mn, min., 48 percent; Fe, max., 7 percent; Si02, max., 10 percent; P, max., 0.18 percent; A1203, max., 6 percent; Zn, max., 1 percent.Later, the specifications were modified gradually. As of May 15, 1943, manganese products were acceptable if they contained over 35 percent manganese and less than 3 percent zinc and 1 percent phosphorus. Prices were based upon material containing 48 percent manganese, 6.0 percent iron, and 11 percent silica plus alumina. Premium were paid for manganese content in excess of, 48 percent and iron content below 6 percent, penalties being imposed upon products containing less than 48 percent manganese or more than 6 percent iron or more than 11 percent silica plus alumina. The specifications for commercial manganese further required that maximum particle size be 12 inches and that 75 percent of the product be coarser than 20-mesh. Therefore, fine material, such as table and flotation concentrates, had to be nodulized or sintered. In addition, carbonate manganese ores were not acceptable unless calcined."

Oct 1, 1947

By Lloyd A. Morley, Robert Stefanko

1. Anonymous (Berggewerkshaftliche Versuchsstrecke), "75 Jahre Berggewerkshaftliche Versuchsstrecke, 1894-1969," 1969. 2. Anonymous, British Symposium on Flameproofing and Intrinsic Safety, IEEE Conf. Report Series No. 3, 1962. 3. Anonymous (Ministry of Fuel and Power), "A Review of Electrical Research and Testing with Regard to Flame-Proof Enclosure and Intrinsic Safety of Electrical Apparatus and Circuits," 1943. 4. Australian Standard Specification, ASC-98, "Electrical Equipment for Explosive Atmospheres," 1970. 5. Belgium Standard Specification, Norme NBM 286, "concernant la protection par enveloppe antideflagrante," 1965. 6. Bossert, J.A., "Approval for Electrical Equipment for Hazard Locations," paper PCI 66-33, IEEE 16th Annual Petrol. and Chem. Ind. Conf., L. A., California, Sept. 15-17, 1969. 7. Bossert, J.A., "Intrinsic Safety in Canada," Electrical Safety Practices, ISA Monogram, vn. 112, 1969. ,8. British Standards, BS229, "Flameproof Enclosure of Electrical Apparatus," 1957. 9. British Standards, BS4683 Part 1, "Classification of Maximum Surface Temperatures," 1971. 10. British Standards, BS4683 Part 2, "The Construction and Testing of Flameproof Enclosures of Electrical Apparatus," 1971. 11. Brown, G.R., and Silver, S., "An Explosion Hazard Due to Inflam¬mation of Aluminum Particles in Flat Flanges of Flameproof Enclosures," CEAL No. 197, Canadian Explosive Atmospheres Labor¬atory, 1969. 12. Campbell, J.D., and Chudleigh, J.P., "Problems Encountered in Designing Electrical Systems for Hazardous Areas," paper PCI-69¬31, IEEE 16th Annual Petrol. and Chem. Ind. Conf., L. A., California, Sept. 15-17, 1969. 13. Canadian Standards Association, C22.2 No. 30, "Explosion-Proof Enclosures for Use in Class I Hazardous Locations." 14. Dainty, E.D., and Brown, G.R., "Explosion Gas Temperatures at the Entrance to Flanges of Enclosures Containing 8.5% Methane-Air Mixtures," CEAL No. 196, 1969.

Jan 1, 1974

By W. W. Adams

"Fatal accidents at coal mines throughout the United States killed 234 employees during January 1924, according to reports from State mine inspectors to the Bureau of Mines of the Department of the Interior, Included in the number of fatalities are 68 deaths caused by two explosions during the month, one explosion occurring in a mine at Johnson City, Ill., and causing 32 deaths, and the other in a mine at Shanktown, Pa., and causing 36 deaths. The fatality rate for the month was 3.94 per million tons, based on a production of 59,435,000 tons of coals In January 1923 the fatality rate was 3.52, based on 206 deaths and an output of 58,458,000 tons.Bituminous mines in all States reported 202 fatal accidents, the production being 51,170,000 tons., and the fatality rate being 3.92, as compared with 3.28 for January last year, For the anthracite mines in Pennsylvania, the reports covered 32 fatalities, which, on the month's output of 7,955,000 tons, indicated a fatality rate of 4.02 per million tons, as against 4.89 for January 1923.As compared with January 1923, the reports for January of the present year indicated lower fatality rates per million tons for all of the main causes of accidents except explosions. For falls of roof and coal, the fatality rate per million tons declined from 1.85 in January 1923 to 1,68 in January 1924; for haulage accidents the rate declined from 0.62 to 0.42; for explosives, from 0.19 to 0.12; for electricity, from 0.12 to 0.07. The rate for explosions increased from 0.21 to 1,31 per million tons. -- Reports of Investigations, Department of the Interior, Bureau of Mines."

Feb 1, 1924

By Charles L. Kimbell

In overview, the world's mineral industry in 1989 registered gains over its 1988 performance, but these gains were by no means as pronounced as had been those of 1988. The traditional statistical measures of mineral industry performance, namely production, trade, and consumption levels, reflected significant growth in most industry sectors from crude material extraction through the gamut of down- stream processing. Growth in market economy countries generally exceeded growth in the centrally planned economy countries as a result of a variety of causes that will be covered subsequently, but even among the centrally planned countries there were some upturns. In contrast to these measures of the soundness of the industry, the situation for nonfuel mineral and metal prices was less satisfactory than in 1988, and low crude oil prices continued as a problem for the all-important petroleum sector, despite some gains during the year. The oil price situation mitigated against price increases for competitive fuels. Although this was unfavorable for fuel producers, it remained advantageous to consumers, including nonfuel mineral producers, processors, and transporters. Thus it cannot be viewed as a negative factor for the whole of the global mineral industry. Global crude mineral output value was estimated at nearly $1,420 billion in current dollars, an increase of 9% over the 1988 level, and an increase in current dollar terms for the seventh consecutive year. Measured in terms of constant dollars, however, adjusting for inflation, the increase was only 4.7% compared with the 1988 level. Despite the prolonged growth trend, the 1989 crude mineral output value level was still 3.2% below the record high set in 1980, which was $1,467 billion in terms of 1989 dollars.

Jan 1, 1992

By Carlton E. Brown, William P. Yant

"INTRODUCTION Direct visual microscopic determination of particle-size distribution and number concentration of atmospheric dust is time-consuming and trying to the eyes. By using the microscope to project images of the particles at high magnification onto a screen much of the eyestrain can be eliminated and particle-size distribution results obtained with less effort and at a considerable saving in time. It also permits simultaneous observation of the images by more than one person. Microprojection requires no more skill and very little more apparatus than is required in the use of the microscope. Anyone familiar with the microscope should be able to obtain as perfect images on the projection screen as in direct visual microscopy since the same laws and limitationsThe theory and practice of microprojection are described in detail in texts. 5/6/ The procedure has been used and found to be satisfactory for measuring the particle-size distribution of sub-sieve-size substances, such as pigments and powder 7/8/ in the same size range as that of atmospheric dust. The Bureau of Mines has used the microprojector and found it to be quite satisfactory for (1) the determination of the number concentration of atmospheric dust R.I. 3289 in samples collected by the Owens jet dust counter; (2) particle-size distribution in samples of atmospheric dust collected by the Owens jet dust counter and by the electric precipitator; and (3) the particle-size distribution of dusts, blood cells, bacteria, and pollen. Work is in progress at this Bureau on the use of the microprojector in counting impinger samples. The use of different kinds of illumination, such as reflected (dark field), polarized, monochromatic, and ultraviolet, in the projection of images of atmospheric dust particles is being considered."

Oct 1, 1935

By Lloyd A. Morley, Robert Stefanko

1 Abaibanel, S , "Deflection of Confining Walls by Explosive Loads," Israel Jour. Technology, vol. 4, n. 1, Feb 1966. 2 Albertoni, S and others, "Numerical Computation Methods for Implosion Processes," EURATOM Proc. of the Conf. on Megagauss Magnetic Field Generation by Explosives and Related Experiments, Milan (Italy), July, 1966. 3 Alexander, S. J , and Hambly, E. C., "Design of Structures to Withstand Gaseous Explosions," Concrete, vol. 4, n 2, Feb. and March, 1970. 4 Anonymous (Belgium Institute of Extractive Industries), "Report for 1968 (covering approved equipment for Belgiums gassy coal mines)," (in French and Flemish), Amales des Mines de Belgigue, n. 6, June, 1969. 5. Anonymous (Ghent Univ., Belgium), "The Welding of Very Thick Steels. Margin of Uncertainty of the Robertson Test," EURATOM Contract 042-61-9-RDB, May 20, 1965. 6. Anonymous, "Inportance of the Nature and Size of Weld Defects with Regard to the Mechanical Strength of Pressure Vessels, (in Flemish), A. Sys. Rev. Soudure, vol. 27, n. 3, 1971. 7. Anonymous (Raentgen Technische Dienst N V., Rotterdam), "Non¬Destructive Welding," Quarterly Report No 13, EURAEC - 1342, March 30, 1965. 8. Anonymous (Staff, USBM Safety Research Center), "Research and Technologic Work on Explosives, Explosions, and Flames: Fiscal year 1969," USBM IC8492, 1970. 9. Anonymous, "Symposium on Flameproofing Intrinsic Safety and Other Safeguards in Electrical Instrument Practice, April 27, 1962," IEEE Conf. Report Ser. 3, 1963. 10. Anonymous, "Unfired Pressure Vessels," ASME Pressure Vessel Code, Sec. 8, 1965. 11. Anonymous, "Unusual Pressure Relief Devices," Industrial and Engineering Chemistry, vol 54, n. 1, Jan., 1962. 12. Archer, G. L., "Design to Avoid Brittle Fracture in Welded Structures," Paper No. 4, Improving Welded Prod Design, vol. 1, Welding Inst., Cambridge, England, 1971. 13. Bailey, F. C., "Buckling and Failure Strength of Plating Panels Loaded in Shear," Final Report NASA Contract NObs-72290, Lessels and Assoc., Inc., Waltham, Mass., Sept. 20, 1963.

Jan 1, 1974

By Maria I. De Rosa

The major fire and fire injury findings for all coal mining categories for 1990-1999 are reported in tables 37-38. Table 39 and figure 13 show the number of fires. fire injuries, risk rates, employees' working hours, and coal production (under- ground and surface coal mines only) by time period for all coal mining categories. Table 40 shows major findings (for under- ground coal mines only) for 1978-1992. For all coal mining categories, 458 fires occurred during 1990- 1999; 157 of those fires caused 164 injuries and 2 fatalities (Ewhr = 2,070 x l0%r, Irr = 0.016: C'P (for underground and surface coal mimes only) - 10,363 x l0\t, Frr = 0.044, LWD = 14,753). Twenty-nine fires and 17 injuries involved contractors. Sixty-six fires required firefighting interventions by mine rescue teams (25 times in underground mines) and fire brigades and fire departments (at least 41 times at surface coal operations). In all, 51 fires destroyed or heavily damaged equipment (including 16 pieces of mobile equipment) because of failure of other firefighting methods, late fire detection, undetected fires, or fire size. A total of 114 fires were detected late, and 42 fires were undetected. The greatest number of fires and fire injuries occurred at surface coal mines; the highest risk rate values were also calculated for this category. For all coal operations, the ignition sources that caused the greatest number of fires were flame cutting/welding spark/slag/flames (1 03 fires or 23% with 69 injuries), hydraulic fluid/fuel sprayed onto equipment hot surfaces (98 fires or 2 1 % with 29 injuries), spontaneous combustion/hot coal (62 fires or 14%), electrical short/arcing (49 fires or 11% with 18 injuries), and conveyor belt friction (3 1 fires or 7% with 6 injuries).

Jan 1, 2004

By G. W. Jones

During the course of an investigation by the Bureau of Mines into the causes, behavior, and control of anthracite-mine fires, it was observed that the carbon monoxide disappeared from a sealed fire area much more rapidly than could be explained on the basis of leakage of gases. Two suggestions were offered for this high rate of disappearance: (1) That the carbon monoxide, was oxidized at temperatures below 150° C. by either the anthracite or its ash (tests on many anthracites have shown that at temperatures above 150° C. carbon monoxide is liberated in the oxidation products when air is passed through it); (2) that the carbon monoxide was oxidized by micro-organisms present in the sealed area.

Jan 1, 1939

By Richard Havens

Acidic and basic uranium leach plant residues located on the Navajo Indian Reservation, Tuba City, Ariz., were successfully stabilized against wind erosion using a relatively low-cost chemical method. An elastomeric polymer chemical was applied to the dike areas and a calcium magnesium lignosulfonate to the beach areas of three tailings ponds. The water-soluble chemicals were applied with an automated sprinkling system. The stabilization cost was $335 per acre for the 34.5-acre tract.

Jan 1, 1969

By B. W. Gandrud

[This report presents the data of one of a series of investigations of the washability of Alabama coals as indicated by float-and-sink tests mode by the Bureau of Fines at the Southern Experiment Station in cooperation with the University of Alabama and Alabama coal producers. The Klandyke mine, operated by the Blocton Mining Co., is about 1 mile eat of Vest Blocton, Bibb County, Ala., floor the southwestern, extremity of the Cahaba coal field. The Bureau of Mines already has published three reports that deal with the, washability of Cahaba coals - one a washability study of the Clark bed at Marvel4/ one on the tabling of fine coal from the Thompson and Woodstock beds5/, and the third a washability study of the Henry Ellen bed at Acmar6/.]

Jan 1, 1939

By D. A. Wilson

A cyclic leaching process was developed for selectively leaching and recovering cadmium from nickel-cadmium scrap battery waste. The six major steps in the process are the following: (1) washing the plates to remove KOH electrolyte, (2) roasting at 550° to 600° C to oxidize metallic cadmium and decompose cadmium and nickel salts, (3) leaching with an ammonium nitrate solution, (4) precipitation of the leached cadmium from solution as cadmium carbonate using CO2 gas, (5) removal of CO2 from the lixiviator by adjusting to pH 4.5, heating, and evacuating the system, and (6) removal of small amounts of leached nickel from the lixiviator using a solvent extraction technique. The regenerated lixiviator is then recycled to leach additional plates. Cadmium extraction was 94 percent and the cadmium carbonate product contained 0.14 percent nickel and 0.12 percent cobalt impurity. The leached plates were smelted to a high nickel-low iron alloy with no detectable amounts of cadmium.

Jan 1, 1971

As mine haulage vehicles become larger, the danger to a driver during a fire emergency is increased by the greater height of the cab above ground. Also, property damage due to fires on bigger trucks can be substantial. To solve this problem, the Department of Interior's Bureau of Mines, through two research and development contracts with FMC Corporation, San Jose, California, has developed two reasonably priced, reliable automatic fire sensing and suppression prototype systems for large haulage vehicles. At the onset of the large mobile equipment fire protection contract effort, it was learned that fires were frequently experienced in open-pit mine haulage equipment, especially large trucks. As the size of equipment has grown, so has the hazard presented to an operator forced to leave his truck in a hurry when fire breaks out and his normal path to the ground is blocked by flames. His only recourse is to jump from the cab platform to the ground, and the one-story drop of 10 feet or more can severely injure him. It is with these factors in mind that a program was undertaken to provide a fire detection and extinguishing capability tor the large mobile equipment, especially trucks, used in open pit mines.

Jan 1, 2012

By H. D. Kline

This publication describes methods and techniques of mining and crushing limestone at 3 of 11 small quarries operated by Anderson-Oxandale Rock Co. in northeast Kansas in 1959. It is one of a series of reports by the Bureau of Mines on methods and costs of mining in various mining districts in the United States. The three quarries selected for study -Bosse quarry, Pottawatomie County; Hansen quarry, Morris County; and Huston quarry, Dickinson County (fig. 1) -were in many respects similar to many others that had been developed solely to fill local and usually transitory demands for crushed limestone for use as concrete aggregate, roadstone, and soil conditioning. Factors governing the choice of quarry sites were quality of limestone, shallow overburden, and proximity to points of consumption of the crushed stone.

Jan 1, 1962

By M. P. Ristenbatt

A new automated post-disaster signaling system, intended to use through-the-earth EM propagation, was demonstrated in the laboratory at an input SNR of -34 dB. The system presently available requires an input SNR of +6 dB, and uses a human-ear detector. The work here demonstrated coherent integration, for the automated system, in multiples of 17 s, up to 1088 s (18 minutes). A repeating pseudorandom (or pseudonoise) signal is used, which offers an ideal auto-correlation at the receiver matched-filter output. A novel decision-variable algorithm achieves the estimate of noise level by using those matched-filter output samples that occur between the signal auto-correlation peaks. This work included corraboration that the received signal power decreases as distance to the tenth power, for through-the-earth propagation. Thus, the above 40 dB reduction in required input SNR permits an automated system to have a range 2.5 times that of the present system. In addition, an automated system permits the possibility of operating receivers around-the-clock; this would reduce the initial-detection-time from a few hours (present system deployment time) to a few minutes (signal processing time).

Jan 1, 1981

By David C. Benson

This Bureau of Mines report is an update of IC 8725 and comprises tables listing the name, location, and other pertinent data concerning certain fuel-related projects. The tables include information on projects involving the proposed or planned development of fuel resources, as well as the development of storage, transportation, and conversion facilities; the report covers the 26 States east of the Mississippi River. Of the total 535 projects for which information is provided, 429 concern coal mines and electric generating plants (including Energy Supply and Environmental Coordination Act (ESECA) coal conversion notices).

Jan 1, 1978

By A. C. Fieldner, G. W. Jones

Tests were made at the Government Fuel Yard , operated at Washington , D. C. by the Bureau of Mines , Department of the Interior , in order to determine and improve the adjustment of the carburetors on the trucks used for transporting coal from the Fuel Yard to the different Government buildings in Washington . The tests were made possible through the hearty cooperation of G , S. Pope , engineer in charge of the Fuel Yard . Joseph Burrows and A. E. Foote of the garage department assisted during all the tests and supplied information on the mileage obtained by the trucks for the months preceding and succeding the time the tests were made . The Mack trucks used range in capacity from 2-1/2 to 7-1/2 ttoonnss .. The majority of the carburetors were Stromberg G- 3 type , as shown in Table 2. During the winter months , when the demand for coal is heavy , from 30 to 35 trucks are used . At the time the tests were made , only about ten of the trucks were in daily use , owing to the small demand for coal during the summer months , and scarcity due to labor conditions . Samples of the exhaust gas were taken on the trucks kept in service for summer hauling in order to determine the carburetor adjustment as used . Changes were then made to a more economical adjustment wherever possible , without sacrificing flexibility of operation and power . In every case the adjustments were maintained for maximum power , but were adjusted to the leanest position to give that power . In all but one case the carburetors were found to be adjusted too rich for maximum power and economy . These results are considered in detail in a later part of this report .

Jun 1, 1923

By Peter Krause

This report provides an overview of the worldwide photographic industry and of the applications of photography. It also covers important technological and market trends, with special emphasis on those factors which may affect the consumption of silver in the future. The text is divided into the following eight sections: 1. Principal manufacturers of silver-based photographic products 2. Major product sectors 3. Structure of the international market for silver-based photographic products 4. Silver-bearing raw materials for the manufacture of photographic products 5. Processing of photographic products: recovery of silver and recycling 6. Methods for estimating the use of silver in photographic products 7. Basic function of silver in photography and alternate image capture and recording systems 8. Brief history of photography Silver- based photographic materials are made for many applications that require different photochemical and physical response characteristics and a wide variety of formats and sizes. All of these products are laminates consisting of a surface-treated support and bonded gelatin layers. Two basic types predominate - films and papers. Films have transparent or translucent plastic supports (mostly cellulose tri-acetate and polyester), while papers have mostly a paper core coated with polyethylene resin layers on both sides (RC type). The front layer contains white titanium dioxide to provide high reflectivity and the back layer a matting agent. However, a few so-called fiber base papers are still supplied. These have a high quality paper base coated with a baryta layer ; i.e. a gelatin layer containing white barium sulfate. The manufacture of photographic film and paper supports requires special procedures and equipment, because of the severe requirements for chemical purity, optical integrity and uniformity (see Table 1 on page 10 for a list of the principal makers of film and paper supports).

Jan 1, 1992

By M. S. Seehra, V. S. Babu, L. Farinash

"The diesel particulate matter (DPM), a constituent of the diesel engine exhausts, is known to be a potential carcinogen. 1- 3 Consequently, suitable methods to control/eliminate DPM have ·been under investigation in recent years. The DPM can be controlled by using fibrous ceramic traps. However, clogging of traps by DPM requires the impractical periodic trap replacement. Following the recent work by Garner and Dent,4,5 we are investigating the in situ use of microwaves to regenerate the ceramic traps, thereby eliminating the trap replacement step in this process. The use of microwaves instead of conventional heating for trap regeneration has the advantage of selective heating of the DPM instead of the trap, if the trap absorbs insignificant microwave power relative to the DPM. Also, the oxidation characteristics of the DPM are needed to understand fully this regeneration process.The rate of energy absorption P per unit volume of a sample is given byP = wE"" |Eo|2 • (1 )where w is the angular frequency, |E0|2 is the intensity of the microwave radiation, and E” is the imaginary part of the dielectric constant (E = E’ + iE”) . Thus measurements of E11 for DPM and ceramic trap material are needed to determine their capacities for microwave absorption. In this paper, we report these measurements carried out at · a frequency of 8.7 GHz. Following microwave absorption, the DPM is expected to oxidize. The oxidation characteristics of the DPM have been investigated using Fourier transform infrared (FTIR) spectroscopy of the evolved gases CO2 and CO and using thermogravimetric analysis (TGA). Finally, some information on the structure of carbon in DPM has emerged from the analysis of its x-ray diffraction spectra. Results of these experiments are reported in the following pages."

Dec 1, 1996

By Ralph L. Brown

As a preliminary step in a recent study4 of the phenols present in a low-temperature tar, the writers prepared the hydroxyacetic derivatives of the simpler available members of the phenol series in order to obtain material to assist in fixing the identity of similar derivatives obtained from the phenols of the tar. When comparing the melting points of the pure derivatives we had made with those given in the literature we were unable to find the characteristics of one of the xylenol derivatives which we had prepared--namely the 1, 3 dimethyl-2-phenoxyacetic acid, In the belief that the compound does not appear in the literature we are presenting these notes on its preparation and its melting point. The hydroxyacetic derivatives are easily prepared and in good yield, and are useful in studying mixtures of phenols. The 1, 3 dimethyl-2-phenoxyacetic acid makes the fifth of the six isomeric derivatives to be reported in the literature. Gluud and Breuer report the preparation of the 1, 3, 4, the 1, 4, 2, and the 1, 2, 4 derivatives. A fourth isomer-¬the symmentrical 1, 3, 5--has been reported by Schutz6, although no record of it occurs in the indexes. The remaining derivative--the 1, 2, 8-has not, been found and it is now being synthesized in the Organic Chemistry Laboratory of the. Pittsburgh Experiment Station. It is true, however, that from a phenolic fraction boiling 215.9 to 2180 isolated from natural petroleum, Tanaka and Kobayashi7 obtained a hydroxyacetic derivative melting at 103.3°. They state that this is the 1, 2, dime ethyl-3-phenoxyacetic acid but present no evidence for the assertion. The known derivatives are summarized in Table 1 following;

Jan 1, 1929

By Charles L. Kimbell

The estimated value of world crude mineral production in 1989 was nearly $1,420 billion in terms of current dollars or more than $1,168 billion in terms of constant 1983 dollars. This latter figure was almost 4.7% above the 1988 level but did not attain the historic high of $1,207.1 billion 1983 dollars set in 1980. The accompanying tabulation provides the latest available revised time series for the value of world crude mineral production in terms of both constant 1983 dollars and current dollars. It also provides one of the two statistical bases for the estimation, this being the data on the value of production of a group of key commodities that was compiled for and published in the authoritative French language mineral industry periodical Annales des Mines for years up to 1983.l It should be stressed that the values just discussed and those presented in the tabulation are for crude minerals only and by no means reflect adequately the role of the entire mineral industry in the world economy. These figures represent only the value of mineral materials as they are mined or otherwise extracted from the earth. They do not reflect the value added to these materials through downstream processing within the facilities commonly accepted as mineral industry plants. That is, value added through beneficiation of ores, smelting, refining, and similar processing is not included in these figures. Comprehensive world data on the value added by such processing are not available; however, a conservative estimate of [ ] the total value of processed output from mineral industry plants derived wholly from primary (newly mined) materials would be on the order of about $2,800 billion constant 1983 dollars or $3,400 billion in terms of 1989 dollars.

Jan 1, 1992