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David H. Browne was born June 8, 1864; at Hollymount, County Mayo, Ireland. At the age of 16, after going through the Londonderry Academy; he came to this country, and entered the University of Michigan, where he was graduated in 1885. He began his scientific practice as chemist, under F. A. Emmerton, in the laboratory of the Joliet Steel Co., after which he served some time as chemist at the Ludington mine, Iron Mountain, Mich. But in 1888 he went back for a year to his alma mater as instructor in inorganic analysis. Those who knew him feel sure that he would have been an efficient and popular professor; but his ardent temperament could not brook the rnonotony and confinement of the class- room; and in 1899 he went to work at the Andrews and Hitchcock blast-furnaces, at Hubbard, Ohio, where he remained until 1891, when he entered as chemist the service of the newly organized Canadian Copper Co., operating in the Sudbury district, Canada. This was the beginning of his special professional life-work. For twenty-six years he devoted himself to the numerous and complex problems successively arising in connection with the metallurgical treatment of the nickel-copper ores of Sudbury. One of his notable achievements was the development of an electro-lytic process for the separation of nickel and copper in the ores referred to. This method was successfully employed for several years; but when the Canadian Copper Co. was absorbed by the International Nickel Co., the cheaper Orford process owned by the latter was substituted. . A still more permanently important piece of metallurgical progress credited to Mr. Browne was the successful firing of reverberatory smelting-furnaces with powdered coal-a measure which had been desired, dreamed and attempted by others, but which he was acknowledged as first to put in practice on a large scale. The Engineering and Mining Journal of April 7, 1917, says editorially of this improvement:

Jan 6, 1917

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from Sept. 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library, freely, and assurance is given that most careful service will be rendered to them.

Jan 5, 1916

By D. F. Strong

Most Newfoundland mineral deposits can be clearly classified as within rocks formed either as accreting plate margins (ophiolitic pyrite-chalcopyrite massive sulfides such as Betts Cove, Whalesback, York Harbour, chromite at Lewis Hills, and asbestos at Baie Verte), at consuming plate margins (Kuroko-type polymetallic massive sulfides such as Buchans and Pilleys Island, porphyry-type Mo-Cu at Rencontre, fluorite at St. Lawrence), or within plates (zinc deposits at Daniels Harbour, sedimentary iron ores at Wabana, manganese in Conception Bay.) As these metallogenic patterns can be convincingly extrapolated southward into the Appalachians and northward to the Caledonides, they provide an important means of eliminating and selecting areas for particular exploration targets. Some criteria are described for the recognition of these environments of differing economic potential.

Jan 1, 1975

Discussion of the paper of J. V. EMMONS, presented at the Pittsburgh meeting, October, 1914. and printed in Bulletin No. 93, September, 1914, pp. 2233 to 2248. ALBERT SAUVEUR, Cambridge, Mass.-Mr. Emmons is to be congratulated for having placed before us in so forcible and satisfactory a manner a question of much importance-that of the surface decarbonization of steel. Of course, both manufacturers and consumers have known for many years that during the heat treatment of high-carbon steel, surface deca.rbonization is always likely to occur to a greater or less degree, but the subject does not seem to have been investigated with the method and thoroughness it deserves. I am in substantial agreement with Mr. Emmons's conclusions, and I have but little to add to what he has so well said. His statement that carbon dioxide is just as effective an oxidizing agent as pure oxygen is likely to cause surprise and some will wonder whether his investigation has been carried far enough to warrant so unexpected a conclusion. The reaction C + 0 = CO, expressing the oxidation of carbon by pure oxygen, is decidedly exothermic, whereas the reaction C + C02 = 2C0, expressing the oxidation of carbon by carbon dioxide, is endothermic. Decarburization by pure oxygen, therefore, should take place much more readily than by carbon dioxide. One cannot help regretting that the author does not mention' the best way of preventing in a practical manner surface decarbonization while treating tool steel and other high-carbon steels.

Jan 4, 1915

By Howard L. Hartman

Probably no aspect of underground excavation is as important or as neglected as the environment. The Committee on Rapid Excavation, formed by the National Academy of Engineering to study the technological needs for "rapid" underground excavation in tunnels, shafts, and mines of the future, encountered a blank wall in attempting to evaluate environmental needs. In fact, so little quantitative information on the extent of present-day hazards is available that projection of future environmental-control demands must await more adequate assessment of current hazard levels. Further, there are not even accepted tolerance standards for many environmental conditions, such as heat, noise, and illumination. Only certain atmospheric contaminants have been satisfactorily catalogued. Any technical study, therefore, which purports to examine the state-of- the-art on underground environmental control must, in reality, settle for a cursory survey of a rather nebulous subject. ENVIRONMENTAL HAZARDS To contend adequately with hazards in the underground environment requires some knowledge of their nature and characteristics. In this regard, it is helpful first to identify our concern: when, where, and to whom or what may environmental conditions constitute "hazards"? Table 1 summarizes considerations that are important in this regard. For the purposes of this Conference (and book), primarily directed toward the excavation process itself, the hazards of consequence occur during excavation (item A) and primarily within the excavation (item B). However, some attention must be given to external hazards as well, since these may affect excavation. The object of concern (item C) is mainly human safety, although property security is also important. Hazards occur in a variety of forms. If one is to devise suitable control

Jan 1, 1970

E. R. Rice, Wickenburg, Ariz. (communication to the Secretary*):—While this paper is primarily intended as a discussion of Mr. Riter's, I think it will be best to indicate my criticism by describing my own field-methods. It has been my experience that, for ordinary work, the regular transit-book is to be preferred to the card-system for recording notes. This is specially true when computations in the field are required, for it is then necessary to have at hand the total latitudes, departures, ancl elevations. Moreover, the transit-book is easier to carry and manipulate in wet or cramped places, and is not as liable to damage as the loose leaf or card. I use a regular transit-book in the field, and then copy my notes, sketches, etc., in an o5ce-book, entering also the latitudes, departures, and other reductions. These values are then copied into the field-book, securing a duplicate record, in case either book should be lost or mislaid. In the field-book, the notes are entered on the left-hand, and the sketches and remarks on the right-hand page. The next two pages are left blank for the latitudes, departures, bearings, reduced distances, etc. Of course, the notes for the different parts of the mine are entered in the field-book in the order in which they are surveyed; but in the they are entered systematically. It has been my experience that the system of keeping notes used by a surveyor, is particularly adapted to the needs and temperament of the individual. Otherwise, he would not be

Jan 1, 1912

The use of the verb in this mood is not as common as formerly: at the time, for example, when the Bible was translated and the plays of Shakespeare were written. Nevertheless it is an essential part of literary English. In editing the 'Mining and Scientific Press' I do not insist upon the use of the subjunctive in articles that are contributed from the outside, but it is deemed proper in all our editorial writing. To speak plainly, the subjunctive is a mark of scholarship; it is ignored by those that are not particular in such matters, and unfortunately it is a source of perplexity to many that are entirely unfamiliar with the use of it. Therefore, as an editor, I think it well to allow the indicative mood to be used by contributors in sentences in which, to be strictly correct, the verbs should be in the subjunctive mood. The fact that most subjunctives are indistinguishable in form from indicatives is another cause of trouble to the uninitiated.* For example, the verbs in such phrases as "Suffice it to say", '(So help me God ", and "God save the King" are in the subjunctive. One reason why the subjunctive is becoming uncommon is the growing habit of expressing the subjunctive meaning by aid of auxiliary verbs that are coupled with the infinitive; thus: "It will sate to say" and "May God save the King". The subjunctive is common in subordinate clauses, and that is how it obtained its name, 'subjunctive', meaning

Jan 1, 1931

By Charles Catlett

Probably no one has had occasion to examine an undeveloped coal property without hearing some hopeful or interested party insist that the bed will improve when opened some distance under cover. When the bed is already in good condition, the opinion is usually advanced that the same character may be expected, at least to the bounds of the hopeful individual's holdings. My attention has been called in this way to the extent to which a bed is affected by its outcrop at the surface ; and having had opportunity to examine a number of openings immediately at the surface, and also a short distance under cover, I submit some observations bearing on this question. Whatever may have been the original variations, we may assume that coal-basins presented in comparatively modern times approximately parallel beds interstratified with fire-clay, slate, sandstone, etc., as represented by Fig. 1. Under the effect of erosion, Fig. 2 would be formed. It is obvious that along the line A, B, C, in Fig. 1, the beds exist under conditions differing from those at A', B', C', or again at A", B", C", in Fig. 2, in their exposures to atmospheric agencies, pressure and erosion. The effect of the first is to decompose and soften many of the strata; of the second, when presented unequally, to cause the movement of such material as was at all plastic towards the point of least pressure ; and of the third, to remove the strata in whole or in part. It

Jan 1, 1901

Bill S.1431 for the creation of a Department of Natural Resources has received a propitious hearing before the Senate Committee on Government Operations. Interior Secretary Rogers C. B. Morton was one of the prominent witnesses who testified in favor. The department had been proposed, Morton said, with "the conviction that the development of all natural resources would be harmonized with the most practicable possible means to protect and preserve the environment, consistent with the social and economic needs of the Nation." Another opinion on the pro side came from Atomic Energy Commissioner Clarence E. Larson, who said that a "total picture" had become essential to the establishment of a policy for developing energy resources in the best public interest. Commissioner James T. Ramey, on the other hand, was one of the AEC dissenters. Ramey said he believed the reorganization of resource responsibilities would hinder efforts to deal with energy-environmental problems and prevent the use of AEC "expertise and facilities" to the greatest advantage. As Arnold Weber, associated director of the Office of Management and Budget, pointed out, however, retiring AEC Chairman Glenn T. Seaborg is in favor of the new department. Another supporter, and one who can cast a vote on the bill, is Sen. Frank E. Moss. Final Standards for emissions from new stationary sources will be published by the Environmental Protection Agency on October 27. The initial proposals, appearing in the Federal Register on August 17, called for limiting emissions per million Btu of heat input (maximum 2-hr average) to 0.2 lb of particulate matter, and, where solid fuel is burned, to 1.2 lb of sulfur dioxide and 0.7 lb of nitrogen dioxide. While the new rules are mainly for new plants, the EPA is also proposing them for "existing plants which are modified in such a way as to increase or alter. . . their emissions."

Jan 1, 1971

By J. W. Gilbert

DuriNG the sinking of the Needmore shaft, on one of the leases of the Eagle-Picher Mining and Smelting Co north of Webb City, Missouri, a very strong flow of water was encountered at a depth of 140 ft. Because OF the speed at which the water rose in the shaft after pumping was discontinued, and in order to speed up sinking operations, a new type of shaft bar and drilling equiprnent was devised, which saved approximately one hour on each shift This bar is made of an ordinary scren type shaft bar with a common drill arm attached to the bar by clamps and welded Into place To this drill arm is attached an ordinary arm clamp with set collar below Through this clamp is attached another drill bar of ordinary length so constructed that it slides back and forth and rotates around the perimeter of the shaft on the set collar A tripod saddle with legs removed is welded to the rotating bar, which enables the drill operator to drill holes at any angle completely around the shaft and also, after an arm extension, permits the drilling of the corner holes without removal of the rig from the saddle Upon completion of the drilling of a shaft round, all that is necessary for the complete removal of the drill machine and shaft bar is to engage the hoist hook through a. ¾-in. eye provided for that purpose on top of the bar and disconnect the air and water lines from the machine, thereby making it possible to pull the whole apparatus out in one piece. At no time is it necessary to remove the machine from the saddle Screw jacks are installed on the vertical bar to further ensure the rigidity of the shaft and bar arm. The accompanying sketch illustrates the details and method of setting up.

Jan 1, 1946

By William P. Blake

THE use of diamonds upon a large scale in drilling rocks, and the substitution to a certain degree of rotary diamond drills for the ordinary steel percussion drills, marks a new era in the art of mining. Since the invention by Leschot of the diamond drill, it has steadily advanced in its utility and range of application, and in the appreciation of miners and engineers. I t must be claimed as one of the many gifts of science to the arts ; and it is, in particular, one of the fruits of the scientific education given at the Ecole Centrale, at Paris. Members are all, doubtless, more or less familiar with the construction of the drill and of the machinery by which it is applied in boring. I t is, therefore, my present purpose only to direct your attention to some recent marked improvements, made by the American Diamond Drill Company, by which the economy and efficiency of the machines have been increased. Form of Bit.-The annular or ring form of the drill-head or bit was, I believe, the earliest; and it is still in use, without essential modification, wherever it is desired to obtain a sample " core" or specimen of the rock traversed. But for mere drilling, regardless ~f the preservation of a test-core, a solid-head bit is preferred, except for very large holes. Until recently, these solid-head bits were made with a pointed cutting face shaped like an obtuse cone. This form was assumed to be the best, being most in accordance with the experience obtained with percussion drills. I t is found, however, that the exact reverse

By William P. Blake

THE use of diamonds upon a large scale in drilling rocks, and the substitution to a certain degree of rotary diamond drills for the ordinary steel percussion drills, marks a new era in the art of mining. Since the invention by Leschot of the diamond drill, it has steadily advanced in its utility and range of application, and in the appreciation of miners and engineers. It must be claimed as one of the many gifts of science to the arts ; and it is, in particular, one of the fruits of the scientific education given at the Ecole Centrale, at Paris. Members are all, doubtless, more or less familiar with the construction of the drill and of the machinery by which it is applied in boring. It is, therefore, my present purpose only to direct your attention to some recent marked improvements, made by the American Diamond Drill Company, by which the economy and efficiency of the machines have been increased. Form of Bit. The annular or ring form of the drill-head or bit was, I believe, the earliest; and it is still in use, without essential modification, wherever it is desired to obtain a sample "core" or specimen of the rock traversed. But for mere drilling, regardless of the preservation of a test-core, a solid-head bit is preferred, except for very large holes. Until recently, these solid-head bits were made with a pointed cutting face shaped like an obtuse cone. This form was assumed to be the best, being most in accordance with the experience obtained with percussion drills. It is found, however, that the exact reverse

Jan 1, 1873

By Reginald S. Dean

THE commercial availability of electrolytic manganese has greatly changed the position of manganese as a nonferrous alloying metal. Manganese metal commercially available up to about ten years ago was reduced with either silicon or aluminum and contained substantial amounts of the oxides of these metals and other impurities. Manganese was accordingly not available as an alloy base and its addition to copper-base and nickel-base alloys was generally limited to a manganese content of a few per cent. Several special alloys like manganin contained up to 12 pct of manganese. A method for the production of electrolytic manganese was developed by the Bureau of Mines in 1936 and commercial production was begun in 1938. At the present time (June 1951), production is about 12 tons per day but appears likely to be substantially increased. Electrolytic manganese is deposited from an aqueous electrolyte containing manganese and ammonium sulphates and is marketed as cathode fragments about 1/8 in. thick. The impurities in its composition are as follows: iron, 0.0015 pct; copper, 0.001; arsenic, 0.0005; cobalt, 0.0025; lead, 0.0025; molybdenum, 0.001; sulfide sulfur, 0.017; sulfate sulfur, 0.014; insoluble, 0.002; carbon, 0.002; hydrogen, 0.015. These figures are from Bulletin 463, U. S. Bureau of Mines. From an alloying standpoint, the most important impurity is hydrogen. This can be removed by heating; 95 pct of the hydrogen can be removed in this way without introducing significant amounts of oxygen or nitrogen. Much of the commercial electrolytic manganese used in alloys is dehydrogenited by the producer, since the amount

Jan 1, 1953

By G. S. Hume

ACTIVE drilling operations for oil were carried on during the summer of 1923 in various parts of, western Canada, particularly in Alberta. During the early part of the summer, interest centered in southern Alberta, in the Coutts area, just north of the producing Kevin-Sunburst field of Montana; but on Nov. 14 a strike of oil by British Petroleums Ltd. at its well near Wainwright, 120 mi. east of Edmonton, diverted public attention to a new field. According to present estimates, this well has a possible production of from 60 to 100 bbl. a day; the oil is 15° Be. with an asphaltic base and is obtained from a sand at the depth of 2019-2036 ft. The oil stands at 1700 ft. in the casing and there is sufficient gas pressure to cause it to flow when the well is opened. The oil horizon is in a sandstone in rocks of Colorado age. It is known that there is a terrace structure of which the western edge extends in a northwesterly direction from the vicinity of Hardisty to Viking, where it probably swings more to the north. At Viking a small dome-like structure on this terrace gives rise to an important gas field. Wainwright lies directly northeast of Hardisty. The exact structure in the Wainwright field is unknown. At Fabyan, 6 mi. northwest of Wainwright, the Imperial Oil Co.1 last year brought 1n a large gas well estimated at 14,000,000 cu. ft.; the escaping gas sprayed a small amount of heavy black oil over the derrick. The gas was obtained at a depth of 2727 ft., deeper drilling encountering a water sand. The results of drilling in the Wainwright field are encouraging for future development.

Jan 3, 1924

H. S. COE, St. Louis, MO. (written discussion *)-I feel much gratified that Mr. Mishler has confirmed those principles of slime settlement expressed by Mr. Clevenger and myself. I wish to state that, when we wrote the article referred to by. Mr. Mishler we had not seen his earlier article in which he gave a formula to be applied to the settling rate off feed pulp for determining thickener area required at El Tigre. It has been my experience that in cyanide work the settling area required is determined by the settling rate of the feed pulp for perhaps 20 per cent. of all of the ores to be encountered. For the other ores, the area required is greater than that indicated by the settling rate of the feed and corre-sponds to the settlement of a somewhat thicker free-settling pulp. Mr. Mishler, in his paper, has thoroughly outlined a set of tests for determining thickener capacity, which, if carefully carried out, should be entirely reliable, provided allowance is made for changes in the mill feed from time to time. Two features of his paper, I, believe; need comment. In speaking of the time required for slime to flocculate after being fed, Mr. Mishler quite properly states that the actual settling rate for the feed pulp can-not be that of completely flocculated pulp because of this time lost in flocculation. It seems to me, however, that this feature cannot be of very great importance, for the following reason: The upper zones of pulp in a thickener may be, and often are, as thin as the feed pulp. If, therefore, the feed be introduced at sufficient depth below the pulp surface to prevent agitation at the surface, there will be ample time for it to become flocculated before it becomes the surface layer, and it, will

Jan 1, 1918

By Richard Moldenke

ONE of the gravest problems of the iron foundry today is the accumulation of sulfur in commercial scrap and its effect on the castings made therewith. The ordinary jobbing castings today show a sulfur content of 0.18 per cent., and occasionally as high as 0.22 per cent. The product of the foundry during the war is undoubtedly .to blame for this rapid increase and conditions will become worse as the millions of tons of gray-iron castings of the war period return to the foundry in the form of commercial scrap. In the ordinary cupola remelting of pig and scrap, at least 0.02 per cent. sulfur is taken up; often double that amount. The high cost and difficulty of obtaining pig iron during the war period compelled the use of considerable scrap in the mixtures; frequently charges containing. 90. per cent. of bought scrap were melted. Naturally the sulfur content of the castings increased. Until the advent of the basic-hearth electric furnace, the only method of holding the sulfur within reasonable limits was to use high percentages of pig in the foundry mixtures. Pig iron seldom contains over 0.05 per cent. sulfur, if well made. With pig iron forming 60 percent. of the .charge and the gates, runners, rejections, and bought scrap the other 40 per cent., the sulfur content of the castings can easily be held down to 0.10 per cent. Pig iron, however, costs more than scrap even when melting loss differences are considered, hence as small a percentage as possible will be used.

Jan 2, 1921

By R. C. Mahon

THE importance of ground water control in glacial drift overlying mines is widely recognized. Adequate handling of the problem results in consider- able saving in overall pumping costs, as the cost of pumping the larger quantity of water under low heads from surface wells is more than offset by the decrease in the quantity of water to be pumped from the mine under high heads. Eliminating or partly reducing seepage of water through the ledge reduces moisture content of the ore, a factor especially important in iron ore mines, where a reduction of 1 pct in moisture effects a very material saving. An important though indeterminate saving is also brought about by the elimination of water in the working places underground. The Homer and Wauseca mines of Hanna Coal & Iron Co. at Iron River, Mich., cover 480 acres. When these mines were started it was possible to operate on only one 40-acre tract, as the depth of water over the remainder of the property was too great to permit operation. Although the average depth of the ground water over the area being mined at that time was less than 50 ft it was necessary to pump 1200 gpm from the mine, the greater part from a depth of 750 ft. The slate footwall and graywacke hanging wall are almost impervious, and it was apparent that seepage into the mine was mainly through the iron formation in which the orebodies were located. Analysis of the water in the iron formation showed it to be of the same character as that in the glacial drift, while the water in both walls was heavily mineralized, also indicating that the water passed much more freely through the iron formation.

Jan 6, 1954

By W. J. McKenna

THE International Smelting Co. concentrator at Tooele, Utah, first operated on a custom basis for the treatment of lead-zinc-iron ores on Nov.' 1, 1924, with a capacity of 500 tons per day. On May 1, 1925, the capacity was increased to 1000 tons per day by the addition of another 500-ton section. The concentrator has since operated on the two-section basis, each treating 500 tons per day entirely by flotation. LABORATORY AND TEST MILL In connection with the concentrator, a well-equipped laboratory and small continuous testing plant are maintained. The flotation equipment in the test plant is of both the Callow and Mineral Separations Sub-"A" types, so that actual concentrator conditions may be duplicated as closely as possible. PURCHASING OF ORE A new shipper usually sends to the plant a 25 to 50-lb. sample, representative of the ore to be shipped. Batch flotation tests are made on this sample to determine its amenability to the concentrator treatment flowsheet and reagent combinations. The results of these tests, which are accurately correlated with those obtained at the concentrator, both as to grades of products and recoveries, determine the actual value of the ore as submitted in the ore purchasing department's treatment schedule. Hearty cooperation has existed at all times between the ore purchasing and operating departments in the selection of ores as concentrator feed. ORE TREATED The basic tonnages for mixtures on the two sections come from the Park City and Bingham mining districts. The Park City tonnages are received by rail and consist of crude ores and gravity mill products. Those from the Bingham district are received by rail and aerial tramway,

Jan 1, 1928

G. R. DELAMATER,* Steelton, Pa. (written discussion t)..-Under the heading, "Preparation of Coal," Mr. Campbell discusses the ad-visability of sizing the coal for the jigs. While I fully realize that conditions alter cases, my method at all times is to do everything possible to avoid sizing. It would be unwise for anyone to say that greater ash and sulfur reduction is impossible by sizing. The thing that can be questioned is, will the greater reduction be sufficient to counterbalance the greater cost? The same thing is true of the proper size of crushing for each individual proposition. In past years many washeries have been built and equipped for wash-ing two or more sizes, but I know of few instances where these plants were operated more than a year before sizing was abandoned. Perhaps in some of these cases this was clue to lack of sufficient development of such scheme of operation; yet I have found that most men engaged in this work, including myself, started into the work with a pretty well-fixed idea that sizing would be beneficial. But trials and tests showed that the mixed size washing is necessary for coals requiring crushing to 1 in. or less. Coal is of low value, compared with other minerals segregated by washing or concentration, for which reason simplicity must be the watchword: simplicity in the machine used to attain the separations of impurities from the coal, in the accessory plant equipment, and in its arrangement.

Jan 12, 1919

By Charles W. Bauer

Most of the aluminum produced in the United States today is derived from foreign bauxite deposits. Earth Sciences, Inc. initiated a program to evaluate domestic non bauxite sources for alumina in the 1960's. In the initial evaluation of alunite, domestic resources were not sufficient to support development. An exploration program led to the discovery of large deposits of alunite in Utah and several other western states. Identification of alunite is difficult as both its physical and chemical characteristics are similar to the minerals with which it is associated. Most of the significant alunite deposits in the western United States are replacement type deposits. These deposits have formed as a result of hydrothermal alteration of volcanic, sub-volcanic, and igneous rocks. Typical alunite deposits contain between 30 and 50% alunite and 50 and 70% quartz, with minor amounts of other minerals. Four mineralogical zones are common in these systems. They include a siliceous zone, a quartz-alunite zone, a kaolinite zone, and a chlorite-montmorillonite zone. Total US reserves of alunite were estimated at 20 Mt fat 30% alunite) by the US Bureau of Mines in 1941. More recent work by the US Geological Survey estimates reserves of 252 Mt and potential resources at 1.4 Gt. Reserves and resources estimated for 23 properties on which field work has been done by ESI are considerably higher. Most of these properties have reserves and potential resources of several hundred million metric tons. The combined demonstrated reserves of these properties are estimated to be about 650 Mt. Inferred reserves are estimated at 2.5 Gt and potential resources at 8 Gt. It appears that the US has sufficient reserves and resources for alunite to be considered as a potential nonbauxite source of alumina.

Jan 1, 1982