Search Documents

By H. S. Munroe

THE native copper of Lake Superior occurs in the form of fine grains and scales, disseminated in small percentage through the copper-bearing rock ; and in large and small masses, from a few pounds to several hundred tons in weight. Formerly the bulk of the copper came from the mines of Ontonagon and Keweenaw counties, producing mass copper. At present these mines furnish less than one-tenth of the total product, and fully one-half of this is from a single mine. The masses are usually found irregularly distributed in nearly vertical fissure veins, and require much dead work in sinking, drifting, and stoping for their development. The risk and expense attending the working of these mines have made them, with few exceptions, anything but profitable. * Read at the Montreal meeting, September, 1880.

Jan 1, 1880

By W. P. Haynes

No wildcat operations are recorded from France during the past year, and no new discoveries have been made. In northern Africa, in Morocco, some prospecting continued in the Gharb and Tselfat regions. Only very small production or shows were found. At the close of the year one cable-tool well (depth 400 meters) was drilling in the Tselfat district, and one rotary well in the Gharb. In Tunisia one well was drilling at Sloughia. Refinery building has been active under the new petroleum law, no less than six plants now being under construction. At Pechelbronn, it is estimated 130 wells were drilled, of which 73 wells, or 56 per cent, were productive. Total drilling was 45,000 m. One new Jurassic horizon was discovered. In the mining area approximately 17,500 m. of new gallery were driven. Production at Pechelbronn for the first nine months was as follows: From wells, 233,013 bbl.; from mines, 164,815 bb1.—a total estimated production for the year of 532,000 bbl. Production at Gabian was 3780 bbl. for the year. In Algeria production from Tliouanet was small, being estimated at 6510 bbl. This production is from Helvetian sands (Miocene) around a salt plug. Italy Production for the year was 211,500 bbl., an increase of 62 per cent over that of last year. Drilling to the extent of 97,000 ft. was done mainly by the A. G. I. P., the government company in the Province of Emilia. More locations are being tested in this area, where geophysical results have shown indications of buried uplifts. Oil has been encountered on two of these structures, at Fontevivo and Podenzano, but the wells have given trouble with salt water. The chief producer is the Societa Petrolifera Italiana at Salsomaggiore and Valezza. The production is from sand lenses at relatively shallow depths. New concessions of 2000 hectares were granted at several points in the Po Valley, and geophysical work is being carried on. The A. G. I. P. is working on a five-year program of exploration to test new areas.

Jan 1, 1933

By A. H. Taitt

The original basis for the search for oil in Great Britain was described last year.t During 1937 the exploratory drilling by the D'Arcy Exploration Company, Ltd. has been continued. Three wells have been completed in the south of England and a fourth is nearing completion. In addition, test wells are now being drilled in Scotland and East Yorkshire. Southern England The test well on the Portsdown structure, which at the end of 1936 was drilling in the Lower Lias at 5792 ft., entered the Triassic at 6540 ft. and was completed in that formation at a depth of 6556 ft., without encountering further indications of petroleum. The Henfield well encountered the Lias at a depth of approximately 4090 ft., and after drilling 800 ft. of an argillaceous development of that formation entered a series of marls, breccias and conglomeratic limestones of the Carboniferous. Drilling was suspended at a depth of 5105 ft., in the latter formation. The consistently impermeable nature of the strata encountered in the Portsdown and Henfield test wells focused attention on the desirability of obtaining shore-line conditions of the Jurassic. With this end in view the Kingsclere anticline, a few miles south of Newbury in Berkshire, was selected for a next test. The Kingsclere well has now reached a depth of 5032 ft. in the Lower Lias and has encountered a full development of the Jurassic. With the exception of the Portland sand, which has a slightly greater porosity, and the Corallian, in which relatively great thicknesses of impervious limestone were met, conditions of sedimentation have been found to be comparable with those of the earlier wells. Small traces of petroleum have been found in cuttings and cores, but formation tests carried out at frequent intervals have yielded no flow of oil. In order to test the Corallian, from which series an outcropping oil sand had been found, a test well was drilled in a near-by anticline at Poxwell in Dorset. The Poxwell well started in the Portland beds and entered the Corallian at 995 ft. The sands at the horizon of the out-

Jan 1, 1938

By C. E. Reistle, G. L. Nye

The East Texas field is in Smith, Rusk, Gregg, Upshur and Cherokee counties, Texas. The discovery well was completed Sept. 8, 1930, near the eastern limit of the field. Within less than one year the new field became the dominant factor in the world production of crude oil. On Aug. 16, 1931, eleven months after completion of the discovery well, there were 1644 wells in the field, and the average daily production was 584,475 bbl. Since that time the number of wells has increased to 8195 on Oct. 1, 1933, and the field has produced 385,979,691 bbl. of oil. The geology of the East Texas field has been discussed by Lahee,1 Levorsen,2 Minor and Hanna3 and others, and it will not be discussed in detail here. The field is a structure of the monocline type on the westward dipping homocline between the Sabine uplift and the East Texas geosyncline. Production is obtained from the Woodbine group, which has been truncated and then sealed by the Austin chalk, which rests unconformably upon it. The oil-saturated part of the sand lies bettween a sub-sea depth of 3050 ft. on the east side of the field, where the Woodbine sand stops and the Austin chalk rests directly upon older formations, and a sub-sea depth of 3320 ft., which was the average depth of the water table in the sand at the time the field was discovered. The field is about 40 miles long and has an average width of approximately 4 1/2 miles. The area within the proven limits of the field is close to 116,580 acres and the normal Woodbine water underlies nearly 62,000 acres on the western side of the field at the present time. The field is unusual in several respects: (1) the tremendous size of the reservoir system and the quantity of oil in place; (2) the large area of the oil and water contact, which makes water movement possible into the oil-bearing part of the structure; (3) the absence of free gas within the main producing sand of the field. Changes in the reservoir pressure during the production history of the field have been greatly affected by

Jan 1, 1934

The following is an incomplete list of members and guests who called at Institute headquarters during the period Jan. 10, 1918 to Feb. 10, 1919. Walter F. E. Barcus. Lt. C. K. McDonald, U. S. N. R. F. Capt. D. H. Bradley, Jr. Major John DeN. Macomb, Bayhead, N. J. Melvis Buigger. - Samuel Melitzer, New York City. Eugene Coste, Calgary, Can. T. C. Merriman, New Haven, Conn. C. W. Cromwell, Warren, Ariz. Wm. J. Millard, Tulsa, Okla. E. O. Daue. Benj. L. Miller, Bethlehem, Pa. Capt. H. W. Edmondson. S. B. Patterson, Jr., Allentown, Pa. E. W. Engelmann, Hayden, Ariz. Lynn L. Pomeroy, New York City. C. Mason Farnham. W. E. Pomeroy, New York City. Lt. C. W. Frith, Salt Lake City, Utah. G. M. Ponton, Ottawa, Ont. John T. Fuller, Honesdale, Pa. Wallace E. Pratt, Ft. Worth, Tex. Walter A. Funk, Idaho Sp., Colo. Harold L. Rau, Milwaukee, Wis. Major W. R. Grunow, New York, N..Y. Lt. E. J. Ristedt, Camp Merritt. A. W. Hackwood, Butte, Mont. George M. Ryall, Los Angeles, Cal. Lt. Nathaniel Herz, New Haven, Conn. D. B. Scott, Mogollon, N. M. Ralph T. Hirsh, New York City., W. H. Staver. O. P. Hood, Washington, D. C. Douglas B. Sterrett, Washington, D. C. E. B. Hopkins, Houston, Tex. J. A. Stewart, Minneapolis, Minn. Hugh C. Ingle, Pensacola, Fla. R. H. Summer, Wilmington, Del. Capt. Wm. F. Jahn. W. G. Swart, Duluth, Minn. Roswell H. -Johnson, Pittsburgh, Pa. Kirby Thomas, New York City. Jesse L. Jones, Pittsburgh. Pa. Capt. H. D. Trounce, San Diego, Cal. Edgar Kidwell, Berkeley, Cal. L. Unger, New York City. .D. H. Ladd, Detroit, Mich. George F. Vivian, Butte, Mont. Raymond B. Ladoo, Cambridge, Mass. R. A. Walter, Reading, Pa. W. H. Landers. Lt. R. G. Wayland, Chehalis, Wash. David Lasner, Elizabeth, N. J. R. J. White, Wallace, Idaho. J. M. Lilligren. J. S. Wroth, Albuquerque, N. M. Lt. Wm. J. Linn, Chicago, Ill. Herbert Hoover, General Pershing, Ambassador William G. Sharp and Admiral William S. Benson were speakers to-day at the annual luncheon in honor of Washington's Birthday, given by the American Club of Paris at the Palais D'Orsay.

Jan 3, 1919

By George Macready

TRINIDAD, British West Indies, is an island near the north coast of South America, situated between latitudes 10° and 11° N:, and. opposite the numerous outlets of the Orinoco River Delta. It is separated from Venezuela by the Gulf of Paria (salt, water) and straits over 5 mi. (8 km.) wide. The area of the island is approximately 1750 sq. mi. (453,- . 250 hectares) and the population is approximately 400,000. The climate is tropical with an annual rainfall of from 45 to 60 in. (114 to 152 cm.). The oil fields consist of several units, or fields, located in the southern half of the island. Approximately 90 per cent. of the total production has been yielded by fields situated within 7 mi: (11.3 km.) of the famous asphalt lake and on the southwest peninsula. The most important producing fields, or units, are the following, which are shown on the accompanying map: Brighton, or Pitch Lake Field, operated by the Trinidad Lake Petroleum Co., Ltd., is situated beside the famous Pitch Lake; it, even encroaches on the lake. Vessigny Field, operated by the Trinidad Lake Petroleum Co., Ltd., is situated 2 mi. (3.2 km.) south of Pitch Lake. Lot One Field, operated by the Petroleum Development Co., Ltd., the United British Oilfields of Trinidad, Ltd., and Stollmeyer, Ltd., is situated 3 mi. south of Pitch Lake upon Lot One of Morne 1'Enfer Forest Reserve and adjoining properties. Parry Lands Field, operated by the United British Oilfields of Trinidad, Ltd., and the Petroleum Development Co., Ltd., is situated 3;2 mi. south of Pitch Lake on Lot Three of Morne l'Enfer Forest Reserve and adjoining properties. Point Fortin Field, operated by the United British Oilfields of Trinidad, Ltd., is situated at Point Fortin, 6 mi. southwest of Pitch Lake. Fyzabad Field, operated by Trinidad Leaseholds, Ltd., is situated several miles southwest of Fyzabad Village and 6 mi. south-southeast of Pitch Lake. Barracpore Field, operated by Trinidad Leaseholds, Ltd., is situated several miles south of. San Fernando and 15 mi. (24.14 km.) east of Pitch Lake.

Jan 9, 1920

By George A. Macready

Trinidad, British West Indies, is an island near the north coast of South America, situated between latitudes 10" and 11" N., and opposite the numerous outlets of the Orinoco River Delta. It is separated from Venezuela by the Gulf of Paria (salt water) and straits over 5 mi. (8 km.) wide. The area of the island is approximately 1750 sq. mi. (453,-250 hectares) and the population is approximately 400,000. The climate is tropical with an annual rainfall of from 45 to 60 in. (114 to 152 cm.). The oil fields consist of several units, or fields, located in the southern half of the island. Approximately 90 per cent. of the total production has been yielded by fields situated within 7 mi. (11.3 km.) of the famous asphalt lake and on the southwest peninsula. The most important producing fields, or units, are the following, which are shown on the accompanying map: Brighton, or Pitch Lake Field, operated by the Trinidad Lake Petroleum Co., Ltd., is situated beside the famous Pitch Lake; it even encroaches on the lake. Vessigny Field, operated by the Trinidad Lake Petroleum Co., Ltd., is situated 2 mi. (3.2 km.) south of Pitch Lake. Lot One Field, operated by the Petroleum Development Co., Ltd., the United British Oilfields of Trinidad, Ltd., and Stollmeyer, Ltd., is situated 3 mi. south of Pitch Lake upon Lot One of Morne 1'Enfer Forest Reserve and adjoining properties. Parry Lands Field, operated by the United British Oilfields of Trinidad, Ltd., and the Petroleum Development Co., Ltd., is situated 31/2 mi. south of Pitch Lake on Lot Three of Morne 1'Enfer Forest Reserve and adjoining properties. Point Fortin Field, operated by the United British Oilfields of Trinidad, Ltd., is situated at Point Fortin, 6 mi. southwest of Pitch Lake. Fyzabad Field, operated by Trinidad Leaseholds, Ltd., is situated several miles southwest of Fyzabad Village and 6 mi. south-southeast of Pitch Lake. Barracpore Field, operated by Trinidad Leaseholds, Ltd., is situated several miles south of San Fernando and 15 mi. (24.14 km.) east of Pitch Lake.

Jan 1, 1921

By Philip D. Wilson

The mines of the Calumet & Arizona Mining Co. are situated in the Warren Mining District, Cochise County, Arizona, between Bisbee and Warren and adjoin those of the Copper Queen Consolidated Mining Co. and the Shattuck Arizona Copper Co. Paleozoic 1imestones.of considerable thickness have been intruded by granite porphyry. A great stock of the intrusive outcrops boldly near the city of Bisbee and is known as Sacramento Hill. From this central core the porphyry has tongued out into the limestone for many thousands of feet as dikes and sills of irregular shape and variable dimensions. Churn drilling has recently developed a large tonnage of secondarily enriched copper ore in the main porphyry mass of Sacramento Hill. While some ore has been found in porphyry in other parts of the district, it is relatively unimportant compared with that which occurs in the Paleozoic limestone as irregular lenses replacing favorable beds near porphyry contacts or associated with well-marked fracture zones often many hundreds of feet away from the intrusive. In a zone extending from Sacramento Hill for a distance of from 1,500 to 3,000 ft., the limestone has been extensively metamorphosed and in this contact metamorphic zone the ore occurs through a known vertical thickness of upward of 900 ft. and individual orebodies often show extension in a vertical direction of over 200 ft. At a greater distance from the intrusive stock, the ore occurs as lenses of greater horizontal than vertical dimensions with an average thickness of approximately 30 ft. An exception to this rule is found in the occasional steeply dipping mineralized fractures, almost true tabular veins, which are found long distances a way from the zone of contact metamorphism. The copper was probably introduced during or slightly later than the porphyry intrusion in the form of chalcopyrite and bornite. These primary copper minerals are always associated with pyrite and often occur as rich lenses in a huge mass or shell of pyrite carrying an insignificant percentage of copper. In many instances the copper-bearing solutions were preceded by siliceous solutions and these latter, often persisting during the period of mineralization, have thoroughly indurated the ore-

Jan 1, 1917

By Frank Schrader

INTRODUCTION THE present sketch is submitted by request in the hope that it may serve as a basis for geologic discussion of the mining camps in Mohave County, which is experiencing a marked revival of activities. The region, commonly known as the Mohave district and Kingman district, lies in western Arizona in the southern part of Mohave County, bordering California and Nevada on the west (Fig. 1). Kingman, the principal-town; is situated near the center of the area. on. the Atchison, Topeka & Sante Fe Transcontinental Railway. This region is composed of naked desert ranges of mountains and broad detritus-filled valleys, the southern extension of the characteristic topography of the Great Basin. In altitude it varies from 500 ft. in the southwest to 8,300 ft. on Hualpai Peak southeast of Kingman. The mountains trend north-northwest. They rise about 3,000 ft. above the valleys, are generally rugged and were formed mainly by erosion. They are composed in the main of a, complex of pre-Cambrian granitoid rocks which underlies the area as a whole. Like the valleys, they average about 10 miles in width. Beginning on the east, they are the Grand Wash Cliffs, the Cerbat Range, the Black Mountains or River Range, and the Eldorado Range. The upper or dominantly cliff half of the Grand Wash Cliffs, marking the edge of the Colorado Plateau, is composed of nearly horizontal sedimentary Paleozoic strata of the Grand Canyon section, and the lower half of the underlying pre-Cambrian complex. The Cerbat Mountains situated in the central part of the area, and the Black Mountains situated between Detrital-Sacramento Valley on the east and Mohave Valley, the great trough of the Colorado River, on the west, are locally flanked or overlain by Tertiary volcanics (Fig. 2). The latter consist of five groups of mountains of which the most important is the Black Mesa group on the south. The Eldorado Range, rising from the great trough of the Colorado on the west and containing Searchlight, Eldorado Canyon, and other camps, is topographically and geologically similar to the Black Mountains.

Jan 10, 1916

By John Birkinbine

Since the presentation of the paper upon " The Concentration of Iron-Ore," which the writer, associated with Mr. Thomas A. Edison, read before the Institute in February, 1889 (Transactions, vol. xvii., 728-744), much time and money have been devoted to applications of various forms of concentrating apparatus, particularly in treating magnetic iron-ores. An indication of the interest which has been developed is shown in the four payers presented at and printed in advance for this meeting." The question, does magnetic concentration pay? is now being discussed by many owners of magnetite deposits, and affirmative answers can be readily obtained from patentees or agents of special machinery, while ultra-conservatism may give a prompt negative reply, based mainly upon the apparent impracticability of handling, crushing, sizing and separating large quantities of ore, and upon the generally

Jan 1, 1891

The personnel of the. Naval Advisory, Board on Inventions, of which Thomas A. Edison is to, be Chairmen, has- been announced. by' Secretary of the Navy Daniels, as follows: W. R. WHITNEY L: H. BAEKELAND American Chemical Society. FRANK JULIAN SPRAGUE, American Institute of Electrical Engineers. B. G. LAMME ROBERT SIMPSON WOODWARD ARTHUR GORDON WEBSTER American Mathematical Society. ANDREW MURRAY HUNT American Society of Civil -Engineers. ALFRED CRAVEN MATTHEW BACON SELLERS American Aeronautical Society. -HUDSON MAXIM PETER COOPER HEWITT Inventors' Guild. THOMAS ROBINS . HOWARD COFFIN ANDREW L. RIKER J American Society of Automobile Engineers. WILLIAM. LAWRENCE SAUNDERS American Institute of Mining BENJAMIN BOWDITCH THAYER Engineers. ? JOSEPH WILLIAM RICHARDS American Electrochemical Society. LAWRENCE ADDICKS WILLIAM LE. Roy EMMET American Society of Mechanical Engineers. SPENCER MILLER HENRY ALEXANDER WISE WOOD American Society of Aeronautic ¬ELMER AMBROSE SPERRY Engineers. ?

Jan 10, 1915

By E. P. Jennings

(Read at the Amenia Meeting, October, 1877.) THE abundance and value of the tellurium minerals of Colorado is well known, but, as yet, few analyses have been made of them, and I offer these as a small contribution to the chemistry of these valuable ores. 1. Native Tellurium.-The specimens from which the analyses of this mineral were made are from the "John Jay" Mine, Boulder County, Colorado, where it occurs in quite large masses, though mixed with more or less silica and iron pyrites. It is usually a fine¬grained, tin-white mineral, but sometimes occurs in distorted, hexag¬onal prisms in cavities in the quartz. Before the blowpipe it gives the reactions for tellurium, sulphur and iron; by cupellation, it yields a small amount of gold. An analysis of a coarsely crystallized speci¬men gave the following results

Jan 1, 1878

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members who registered at Institute headquarters during September: William B. Phillips, Austin, Texas. Will L. Clark, Jerome, Ariz. Olof Wenstrom, Boston, Mass. Robert H. Richards, Boston, Mass. Anthony F. Lucas, Washington, D. C. Hennen Jennings, Washington, D. C. P. H. Griffin, New York, N. Y. Waldemar Lindgren, Boston, Mass. H. N. Lawrie, Portland, Ore. C. Snelling Robinson, Youngstown, 0. Clarence P. Linville, Everett, Pa. E. P. Ross, Johnson, Tenn. Members of the XII International Geological Congress who made the Institute Office their headquarters while in New York A. Bigot, Caen, France. E. Gentil, Paris, France. J. Caillebotte, Paris, France. H. Saint-Clivier, Paris, France. John Ashworth, Manchester, England. Tadasu Hiki, Kioto, Japan. T. Dahlblom, Falun, Sweden. L. Milch, Greifswald, Germany.

Jan 10, 1913

By A. Blake Caldwell

The continental margins and ocean basins represent by far the largest unexplored frontier for discovery and development of mineral values. In April 1971, Deepsea Ventures, Inc., at a press conference in its Gloucester Point, Va. headquarters, announced what may become the first commercial deepsea venture--15,000 ft below the ocean surface. During the presentation, Deepsea's president, John E. Flipse, announced that studies made by company personnel had proven the feasibility of mining, transporting, and milling L million tpy of manganese nodules taken from the ocean floor, and that, based on current conditions and prevailing construction costs, a venture of this magnitude would cost about $200 million split evenly between mining and processing facilities. A subsidiary of Tenneco, Deepsea has tentatively reserved 1976 as the year in which it plans to mine, process and market the nodules.

Jan 1, 1971

By Jack Fox

Three years ago we attended the V International Mining Congress in Moscow. This year we attended the VI International Mining Congress in Madrid. By almost any criterion, this was a most successful convention. There were 1717 registrants, not counting the ladies. I don't know how many of the latter there were, but they certainly made a welcome addition to the group. Once again, the International Organizing Committee put together a very impressive technical program which the Spanish National Committee backed up with a brand new Palacio de Congresos admirably equipped with simultaneous translation devices and an organization that provided an excellent social program, a tremendous set of post- meeting excursions, and very impressive opening ceremonies, entertainment and closing ceremonies. There was also an exhibit on the subject of Spanish and Spanish American mining history in the Palacio de Congresos.

Jan 1, 1970

By Richard K. Thorpe, Gordon D. Anderson, Merle E. Hanson, Ronald J. Shaffer

The propagation of pressurized fractures across a frictional interface is discussed, with emphasis on the case where an offset, or step, in the crack is produced. Theoretically, the steps can occur at regions of reduced shear strength along the interface. As a fracture is propagated toward a weak zone, extensional strain is concentrated at the edges of the zone where higher shear stresses can be sustained. Thus, when the fracture intersects the weak zone, it can be reinitiated at some small distance away on the opposite wall of the interface. The phenomenon has been studied through numerical modeling and laboratory experiments of the hydraulic fracturing process. Field observation of natural step cracks indicates that the mechanism is applicable to the genesis of jointing patterns in rock. Such features should not be confused, therefore, with steps caused by shear displacement of an interface.

Jan 1, 1982

By R. W. M. Lai

INTRODUCTION Manganese nodules were first discovered by the H.M.S. CHALLENGER expedition of 1873-76 and have engaged the interest of oceanographers and natural resources engineers ever since (1-4). Manganese nodules, some of them as large as grapefruit, cover vast stretches of the ocean floor throughout many parts of the world. In some areas the ocean floor is literally paved with nodules. The Pacific Ocean alone is estimated to contain 1.5 trillion tons of nodules which are forming at the rate of about 10 million tons per year (2). An analysis of the principal metal values for Pacific Ocean nodules is shown in Table I (5). [ ] The principal ingredients of the nodules are manganese and iron, but they also contain other important associated metal values such as copper, nickel, cobalt, and molybdenum. These associated metal values,

Jan 1, 1980

By G. M. Ritcey

The design of the plant facilities together with the necessary equipment required for the operation is at an optimum only for the specified plant with its peculiar priorities and preferences. Because many alternatives in design are possible to suit a particular plant, each plant designer and contractor must choose carefully in the selection of the site, design and choice of materials of construction, as well as the type of equipment necessary for the process. Basic factors as efficiency, dependability, simplicity, and safety must be considered early in the construction; while the choice of equipment, materials of construction, possible corrosion problems, automation, maintenance, effluents disposal and tailings dam construction can greatly affect the plant costs. While existing plants are in operation, the know-how gained from the operating experience of those plants can be invaluable in the new plant planning, design, and construction.

Jan 1, 1978

By Yoginder P. Chugh

Elastic and viscoelastic behavior of three rocks-Tennessee sandstone, Barre granite, and Indiana limestone-was studied experimentally under uniaxial tensile stress. Cylindrical specimens of these rocks, about 1.0 in. diam and 2.0 in. long, were subjected to incremental constant stress history under uniaxial tension. The stress was held constant for a period of 40 min at each stress level. During this period, longitudinal and transverse strains on specimens were continuously monitored. The straintime history at each stress level was analyzed for elastic and viscoelastic parameters of a generalized Burger model. The viscoelastic parameters under uniaxial tensile stress were compared with those under uniaxial compressive stress. The experimental setup, experimental procedure, analysis techniques, and more significant results are described. This limited research effort clearly indicates the importance of the mechanical behavior of geologic material under tensile stresses.

Jan 1, 1975

The total value of world offshore mineral production in 1970 is estimated around $180 million-less than 1% of the total onshore value for that year (Table 1). As such, offshore mining is still a relatively small industry. Commercial operations center around production from unconsolidated surficial deposits lying in shallow waters of the continental margins. While minerals recovered include sand and gravel, iron, tin, limestone, and aragonite, other possible mineral targets have been identified For consolidated deposits, only two offshore operations are known to exist. They are Alaska Barite Co.'s Castle Island mine (see p. 46) and Freeport Minerals Co.'s Grand Isle mine in Louisiana. At Grand Isle, sulfur is recovered from an offshore platform utilizing the Frasch process. Also, Freeport recently announced reactivation of its offshore Caminada sulfur mine at an estimated capital cost of $23 million.

Jan 4, 1975