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By N. J. Sather

A detailed description is given of Bunker Hill's concentration process employed at the company's lead-zinc property in the Coeur d'Alene district, Idaho. The plant is equipped to process 3000 tpd of Pb-Zn ore. The history of the Bunker Hill mine dates back to Aug. 26, 1885, when Noah S. Kellogg found the outcrop of the Bunker Hill orebody on the hillside of Milo Gulch above the present town of Wardner, Idaho. A small concentrator was erected in 1886, and before the railroad came, the mine output was transported by mule teams to the head of navigation on Coeur d'Alene Lake. After ten years of production, an interest was purchased in the Tacoma smelter at Tacoma, Wash., to which the entire output was shipped. In 1916 and 1917, a modern lead smelting plant and refinery was erected, and a modern electrolytic zinc reduction plant was built in 1927-1928 by the Sullivan Mining Co. which was 50 pct owned (and now totally owned) by the Bunker Hill Co. The first concentrator, a 100-tpd capacity plant, was built in 1886 near the Reed Tunnel in Wardner. The treatment consisted simply of crushing ore to 2 in. and then to 1/2 in. through rolls in closed circuit with a bucket elevator and trommel screen. The undersize was further sized in trommels to 10 mm and 3 mm. Oversize from the latter was treated in Hartz jigs. The 3 mm undersize was classified in crude hydraulic classifiers furnishing sands to sand jigs, the overflow being dewatered in a long V tank which supplied sands to a Cornish buddle and to Frue vanners. The concentrates were of excellent grade, old records showing assays of 69 pct lead and 29 oz. of silver per ton. Tailings were high inasmuch as the provision for treating the slimes was inadequate. Since the erection of the first mill, the Bunker Hill plant has gone through many changes and improvements. In succeeding years, the flowsheet was enlarged somewhat with Huntington and Chilean mills, vanners, tables, ball mills, and flotation cells being progressively added. In the transition period to the present day practice, the object was not only to improve the equipment for better mechanical performance, but to add new equipment whenever practicable so as to improve both grade and recovery of the product at a lower cost. For the modern plant and flow-sheet, see Figs. 1 and 2. The history of flotation at Bunker Hill dates back to 1913 when experimental work was done in a cell in which the pulp was circulated through a centrifugal pump set outside the cell and discharged against a baffle in the cell. The cell was built with a spitzkasten, and the quiet zone in the latter tended to let the froth break down before it got to the overflow weir. To remedy this situation, a belt drag with light metal flights was arranged for drawing off the froth over a ramp in each cell. Recovery of lead was not as high as present day practice, but was so much better than the vanners that the cells were multiplied gradually to eight cell units. The mill men called them mud hens. Flow between the cells was controlled by a weir, which determined the pulp level in each cell. These early machines were called Bunker Hill machines. The tailings were later treated in pneumatic scavenger flotation machines in a series, producing concentrates for retreatment in the Bunker Hill cleaners as well as the final tailings. This system of flotation served with minor changes until the Fahrenwald machine was developed at Bunker Hill during the period from 1921 to 1925. In 1925, the Fahrenwald flotation machine gradually replaced the Bunker Hill machine, although the Hearing pneumatic scavengers for retreatment of the tailings from the Fahrenwald machines were retained in the lead section until 1928. The use of the Hearing pneumatic machine for cleaning the rougher concentrates was begun in 1924. In 1941, plans were made for remodeling and modernizing the concentrator, the goal being a modern concentrator employing the latest equipment and milling practices. The old wooden building was to be replaced by a steel and concrete structure. Shortly after preliminary work got under way, the United States entered World War II and the demands for metals increased. To meet this requirement, the management decided to increase the capacity of the concentrator to 1800 tpd. This was accomplished in record time by the construction and operation of a sink-float plant. Installation of this plant was the first step in the general plan for modernization. In 1947 the concentrator (including the sink-float plant) was enlarged to handle 3000 tpd. Milling operations today are at the rate of 2300 tpd, five days per week. During 1959, 453,000 tons of ore was beneficiated. The Bunker Hill concentrator is in three sections: the crushing plant, a 3000-ton capacity storage bin, and the concentrator building. The crushing plant is of wood design with a gunnite coating on the exterior.

Jan 1, 1961

By C. A. Hartnagel

The production of petroleum in New York in 1940, totaling 4,999,000 bbl., was only slightly under the amount produced in each of the previous three years. The year 1940 started auspiciously with a posted price on Jan. I of $2.75 a barrel. Four price reductions, beginning in May, resulted in August in a low of $1.85 a barrel, after which two increases brought the year's closing price to $2.15 a barrel. The favorable crude price at the beginning of the year stimulated an increased drilling program, especially in the water-flooding districts. In the Allegany County region, which accounts for about two-thirds of the state's oil production, 886 wells, including water-intake wells, were drilled; 200 more than in the preceding Year. During the closing months of the Year there was a marked decline in the number of wells drilled. The unfavorable position in which the industry found itself before midsummer was due largely to the loss of export markets for its high-grade lubricants, constituting approximately 25 per cent of its business. As a result of this situation, runs to refineries were curtailed as much as 30 Per cent at the middle of the Year. Improvement in market conditions toward the end of the Year found the stocks of available crude at an almost record low. Deep DRILLING with the gradual exhaustion of some of the important natural and flood-oil-produc-ing areas of the Allegany and Bradford pools, overproduction will not be a serious problem in the future. The possibility of finding new territory or deeper producing sands has been further lessened by the drilling of additional deep wells for gas in and about the present oil fields. Many of these wells drilled to the Oriskany sand-stone were over 4000 ft. deep and have tested the entire thickness of the Devonian formation, the upper 2000 ft. of which contain all the important oil-producing strata in the state. Water-flooding It is thus evident that the problem of the New york oil producers is not one of find-ing new supplies but of obtaining as much 6 oil as possible from the old developed fields that during the 60 years of their life have 1 produced I 3o,ooo,ooo bbl. of oil. Although a few floods were in operation before I9I9, when the production of oil by flooding was 1 made legal, the output for that year amounted to only 85I,000 bbl. From 1919 I on there has been an almost constant increase, which during the past four years has averaged well above 5,000,000 bbl. annually. During the last 22 years, which constitutes the period of important flooding operations, 651337,000 bbl. of oil have been produced in the state. Careful estimates indicate that between one-third and one-half of the oil fields are being flooded or are already watered out. Some of the flooded and watered-out areas include territory with unusually thick sands, which were highly productive during the early history of the fields. From a recent study of operations in the New York oil fields, it is estimated that about 65,ooo,oo bbl. of oil

Jan 1, 1941

By C. A. Hartnagel

The production of petroleum in New York in 1940, totaling 4,999,000 bbl., was only slightly under the amount produced in each of the previous three years. The year 1940 started auspiciously with a posted price on Jan. I of $2.75 a barrel. Four price reductions, beginning in May, resulted in August in a low of $1.85 a barrel, after which two increases brought the year's closing price to $2.15 a barrel. The favorable crude price at the beginning of the year stimulated an increased drilling program, especially in the water-flooding districts. In the Allegany County region, which accounts for about two-thirds of the state's oil production, 886 wells, including water-intake wells, were drilled; 200 more than in the preceding Year. During the closing months of the Year there was a marked decline in the number of wells drilled. The unfavorable position in which the industry found itself before midsummer was due largely to the loss of export markets for its high-grade lubricants, constituting approximately 25 per cent of its business. As a result of this situation, runs to refineries were curtailed as much as 30 Per cent at the middle of the Year. Improvement in market conditions toward the end of the Year found the stocks of available crude at an almost record low. Deep DRILLING with the gradual exhaustion of some of the important natural and flood-oil-produc-ing areas of the Allegany and Bradford pools, overproduction will not be a serious problem in the future. The possibility of finding new territory or deeper producing sands has been further lessened by the drilling of additional deep wells for gas in and about the present oil fields. Many of these wells drilled to the Oriskany sand-stone were over 4000 ft. deep and have tested the entire thickness of the Devonian formation, the upper 2000 ft. of which contain all the important oil-producing strata in the state. Water-flooding It is thus evident that the problem of the New york oil producers is not one of find-ing new supplies but of obtaining as much 6 oil as possible from the old developed fields that during the 60 years of their life have 1 produced I 3o,ooo,ooo bbl. of oil. Although a few floods were in operation before I9I9, when the production of oil by flooding was 1 made legal, the output for that year amounted to only 85I,000 bbl. From 1919 I on there has been an almost constant increase, which during the past four years has averaged well above 5,000,000 bbl. annually. During the last 22 years, which constitutes the period of important flooding operations, 651337,000 bbl. of oil have been produced in the state. Careful estimates indicate that between one-third and one-half of the oil fields are being flooded or are already watered out. Some of the flooded and watered-out areas include territory with unusually thick sands, which were highly productive during the early history of the fields. From a recent study of operations in the New York oil fields, it is estimated that about 65,ooo,oo bbl. of oil

Jan 1, 1941

By Don Masson

MUCH has been written and many prophecies made on the subject of plastics as a replacement for metal, and the extent to which these materials will compete with each other for peace- time markets. (Metal is used in a broad sense to include all types.) But although certain synthetic resin materials have made considerable headway in war production, this change to plastics can hardly be regarded as a serious threat to the mining and metallurgical industries. Even today, the total yearly tonnage of plastic materials is approximately only 1 per cent of that of steel, and only a small fraction of this might be considered as actually replacing steel. However, these figures must not be taken as indicating that the importance of plastics in fields hitherto considered exclusively the territory of metals is negligible-far from it. Considering the comparatively minute tonnage of plastics now being produced in comparison to the output of metals, the number of applications where plastics have augmented or aided the sale of metals is considerable.

Jan 1, 1944

By Samuel S. Wyer

THE installation of the gas-producer power-plant in America has been so unusual that all engineers have viewed it with in¬terest; a large majority, however, regard it with a lack of con-fidence and many with positive distrust. Despite the fact that European engineers have usually been less inclined to take the initiative along experimental lines than are Americans, they have, nevertheless, developed the gas-producer plant to a very high state of efficiency to which they were forced by the neces¬sity of economy in fuel-consumption. The gas-producer power-plant is so common in Europe that engineers as well as the general public regard it with the same degree of confidence that is now universally placed in steam¬plants. Gas-engines, both small and large, are in general use there, and central stations, aggregating several thousand horse¬power, are quite numerous. The fact that gas-producer power-plants have received so little attention in America may be attributed to five conditions:-1', ignorance and prejudice; 2, newness of work; 3, in-

Mar 1, 1905

NEW MEMBERS The following list comprises the names of those persons who became members during the period Aug. 10. 1918, to Sept. 10, 1918. BATCHELOR,. HARRY D., Laboratory Director, National Carbon Co., Inc., Cleveland, Ohio. BROWNING, C. P., Gen'I Supt., Britannia Min. & Smelt. Co., Ltd., Britannia Beach, B. C., Canada. COMSTOCK, GEORGE F., Met., Chg. of Physical Test Laboratory, Titanium Alloy Mfg. Co., Niagara Falls, N. Y. CONCKLIN, BERT M Chief Engr., Arthur lron Mill. Co., Hibbing, Minn. COWAN, W. A., Asst. Chief Chem., National Lead Co., 129 York St., Brooklyn, N. Y. DAVIDSON, PHILIP Met., Scovill Mfg. Co., Waterbury, Conn. DAVIS, Louis L., Mgr. & Treas., Commonwealth Min. Co., 911 Foster Bldg., Denver, Colo. DAY, P. W Chem. Engr., Western Cartridge Co., 207 E. 12th St., Alton, Ill. DECKER, HAROLD DEBIT, Co. A, 27th Engineers, A. P. 0. 714, A. E. F., Care Postmaster, N. Y.

Jan 10, 1918

By K. A. Svanstrom, W. R. Opie

Problems associated with deposition of titanium infused chloride baths using TiCl4 as a feed material are reviewed. A potentially workable cell design using Alumdum diaphragms is discussed. Problems inherent to diaphragm-type cells are emphasized and experiments described which led to the development of a cell without a diaphragm. INVESTIGATORS assigned the problem of developing a commercial electrolytic process for making titanium metal have found that they are faced with the difficulty of overtaking rapidly improving magnesium and -sodium reduction processes. The ultimate goal must be a simple process that can be conducted with low-cost raw materials in equipment that is inexpensive to build and operate. This paper deals with some work of a preliminary nature conducted by personnel of the Research Laboratories, National Lead Co., Titanium Division. Many others have reported on the general subject of depositing titanium from fused salt electrolytes. A partial bibliography is attached. PRIMARY CONCEPTS Anyone attempting to deposit titanium metal from fused chloride electrolytes using TiC14 as a source material is faced with at least the following problems: 1) Getting the titanium into solution in the bath. 2) Controlling oxidation and reduction reactions associated with multiple valency of titanium, which result in low electrical efficiency. a) Prevention of dichloride oxidizing to trichloride and trichloride to tetrachloride at the anode. b) Prevention of trichloride from being reduced only to dichloride at the cathode. 3) Prevention of metal formation away from the cathode thru disproportionation of titanium dichloride to satisfy the equilibrium. 3 TiCl2 == 2 TiCl3 Ti [I] 4) Protection of reduced chlorides in the bath from reaction with oxygen from the bath container or air. 5) Removing from the bath the deposited metal formed without allowing it to become contaminated with oxygen or nitrogen. 6) Selecting cell materials of construction which will not contaminate the metal product or cause cell inefficiencies. EARLY EXPERIMENTS The initial attempts made to electrodeposit titanium from fused chloride baths using TiCl4 as a source material indicated that TiCl4 was essentially insoluble in molten chlorides of alkali and alkaline earth metals. If, however, the TiCl4 was introduced close to a nickel cathode some metal could be formed and appreciable quantities of reduced chlorides would be present. These reduced chlorides reacted with any oxygen present in the atmosphere above the bath and would also diffuse quickly to the anode (graphite) where they would react with chlorine and be evolved as TiCl4. The net electrolytic efficiency of such a cell is essentially nil. The TiCl4 evolves from the anode at almost the same rate that it is introduced in the vicinity of the cathode although a small amount of titanium metal can be formed on the walls of the cathodic pipe. It becomes apparent from the operation of such a cell that: metal can be deposited on the cathode, although of small particle size and a nonadherent nature, and when reduced chlorides are present in the electrolyte, TiCl4 can be absorbed, probably by the following reactions: TiCl4 + TiC12 - 2 TiCl3 [21 2 TiCl3 + 2 faradays - 2 TiC12 + C12 [31 DIAPHRAGM CELLS These facts encouraged the development of cells containing diaphragms to prevent migration of reduced chlorides from the cathode area to the anode. Small-scale cells for process development are described by Alpert, Schultz, and Sullivan.20 A larger brick-lined cell incorporating internal heating by passing ac through the bath is shown in

Jan 1, 1960

By C. L. Mantell

When considered from the viewpoint of world annual output, tin is one of the rarest metals. Its annual production is exceeded by that of iron, copper, lead, zinc. aluminum, magnesium; probably by that of the ferroalloys of manganese, chromium, and silicon, and possibly by the world production of sodium; while it exceeds only the output of such common metals as nickel, antimony, mercury, tungsten, molybdenum, silver, gold and the precious metals. Cassiterite, or tinstone, until the second World War was the only mineral that was an important source of tin. This mineral is frequently called "tin ore." The use of the term should be restricted to the ore containing the mineral, and not, in addition, to the concentrates of the mineral obtained from the ore or from stanniferous alluvial deposits. There is a general misuse of the term "tin ore" in the Malay Peninsula and adjacent localities, particularly where most of the mineral is obtained from secondary stanniferous deposits. The term "cassit-erite" is exclusively used in mineralogical, geological, and other scientific writings; it is unfortunate that it is not mole frequently used when referring to the occurrence of the mineral on an economic scale. Ores "Tinstone" js a very convenient old English term deserving a more frequent use. Tinstone is a dioxide of tin, or stannic oxide. When chemically Pure, as in the very rare transparent variety, it has a metallic content of 78.6 per cent tin. Frequently, however, the crystals and grains contain appreciable amounts of impurities, chiefly iron and tantalum. The impurities here referred to are those actually in the mineral itself. Tinstone usually has a deep brown or black color with an adamantine luster. Several other colored varieties are known, among them red ruby tin, yellow rosin tin, and yellow wax tin. the names jn each case being descriptive of the mineral's appearance. Ainalite is a variety of cassiterite con-taining almost g per cent of tantalum pentoxide. Sparable tin, tooth tin, and needle tin, as a result of their acute dite-tragonal pyramidal crystalline form, re-ceive their names from their crystallo-graphic appearance. Wood tin is a compact variety of cassiterite composed of radiating fibers resembling dry wood. Toad's-eye tin is a similar variety on a smaller scale in which the fibers appear to resemble the eye of a toad. Stream tin is water-worn tin-stone. Float tin is sometimes employed to describe the cassiterite occurring in soil derived from the weathered surface of a mineralized area. Stannite is an ore of tin of lesser impor-tance than cassiterite. It is a sulphide of tin, copper, and iron, sometimes known as tin pyrites or bell-metal ore. Its chemical com-position is sometimes expressed by the for-mula Cu,S.FeS.SnSz with zinc usually present in varying quantities. The tin con-tent varies from 22 to 27 per cent and there is about 29 per cent of copper, 13 per cent of iron, and 30 Per cent of sulphur.

Jan 1, 1944

Abadilla, Quirico A., Geol.. Lago Pet. Corp Box 172 Maracaiho, Venezuela. IIAbbw. Robert Graham. The W. W. Sly Mfg. Co.Train Ave.. Cleveland. Ohio. Abbotf A. N., Mines Supt., Maznpil Copper Co.. Ltd..Conception del Oro, Zac., Mexico. Abbotf Clarence E, Mgr.. Mines & Quarries, Tenn. Coal. Iron & R. R. Co., 1242 Brown Marx Bldg., Birmingham, Ala. Abbott. Louis Benjamin. Chief Engr.. Consolidation Coal Co. ... .Elkhorn Div., Jenkins, Ky. Abeel, George 8.. Jr., Cons. Min. Engr...4612 West 17th St., Los Angeles, Cal. Abel. Albert E.. Asst. to Pres.. Valley Mould & Iron Corp..Hubbard, Ohio. Abel. Raymond L Asst. Prof., Dept. of Pet. Refin.. Univ. of Pittsburgh. .. .Pittsburgh. Pa. Abernathy. George Elmer. Prof. of Geol. & Min.. Kansas State Teachers College. Pittahurg. Kans. Abernethy, D. Carl, Jr. Min. Engr., Hudson Coal Co. .Scranton, Pa. Abw, Hirouhi. Min. & Met. Engr., Min. & Met. Dept., The Higher Technical School, Osaka, Japan. Aborn. Robert H.. Research Assoc.. Mass. Inst. of Tech..Cambridge, Mass. Abouchar. Bylvain Sley. Min. Engr. & Geol., c/o S. H. Sekaly, 13 Rue El Nimr, Cairo, Egypt. tAbozeid. Mahmood. Pet. Min. Engr., Marland Oil Co. of California, Subway Terminal Bldg., Los Angeles, Cal. Abraham. Arthur W.A. pt. 40, Barcelona. Anzoatmui, Venezuela. Abrahams. Alexander I.. Gen'l Mgr., Racon Electrical Co.. ..... .Slough, London, England. tAbrahamuon, C. W., Min. Engr.. The Mond Nickel Co., Ltd.. ..... .Levack. Ont., Canada. Abstein, Henry T.. Engr. & Mgr.. Profile-Tamarack Mines Co.. ...... .Yellow Pine, Idaho. tAcker, E. WC.. Met.. ........ .I28 East Washington Lane. Germantuwn. Philadelphia, Pa. IlAckerman, D. E.. Research Engr.. Research Lab., International Nickel Co., Bayonne, N. J. tAckerman. Ernest R., Pres., Lawrence Portland Cement Co.. . .Plainfield, Union Co., N. J. Adachi. Jinzoo.A..d dress Wanted Adachi, Yuichi, Chief Engr.. Anzan Steel Works, South Manchuria RY. Co., Anzan, South Manchuria. China. (Via Dairen). Adair, Arthur C, Valuation Engr., Internal Revenue. Treasury Dept.. . .Washington, D. C. Adami. Arthur E., Prof. of Min. Engrg., Montana State School of Mines. Butte, Mont. Adami. Charles J.. Min. Engr., Gen'l Mnr., St. Jos~ph Lead Co.. ....... .Bonne Terre, Mo. Adama, C. W., Pres. Adams Pacific Corp .I66 Montgomery St., San Francisco. Cal. Adams. Cuyler .Dee rwood, Minn. Adams, David T, 514 Wrigley Bldg.. Chicago, Ill. ADAMS, FRANK DAWSON, Logan Prof. of Geology and Dean, Faculty of Applied Science. McGiU Univ., Montreal. Que.. Canada. Adams. Gale L, Research Engr.. General Pet. Corp...Los Angeles. Cal. Adams. George I.. Prof. of Geol. & Mineralogy. Univ. of Alabama. .Tuscalmsa, Ala. Adams. H. H.. Cons. Gml..Room 415, W. T. Waggoner Bldg., Fort Worth. Tex. Adams, Henry, Cons. Min. Engr. . 934 Park Ave., Plainfield, N. J. Adame, Henry H. 285 Madison Ave., New York. N. Y. Adams. Henry Farnum. Engr.. Charge Experimental Work, Inspiration Concentrator. Inspiration Cons. Copper Co.. Box 364, Inspiration. Ariz. Adams, Huntington, Min. Engr, 149 Broadway, New York, N. Y. Adams. Leland D, V.P.. Leslie-California Salt Co., 166 Montgomery St.. San Francisco. Cal. Adams. Louie W.. Illinois Steel Co Gary, Ind. Adama, XL L. Min. Engr.. Old Ben Coal Corp., Mine 12.. Christopher. IU. Adams, Robert M. Robert M. Adam Co. .I201 Fidelity Bldg., Duluth, Minn. Adams. Sidney F.. Geol., Empire Zinc Co .Gilman, Colo. tAdams, Waldo Peck..P ittsfield, Pike Co.. Ill. Addams. Charles 1. Min. Engr.. Bo x 663. Phoenix, Ariz. Addicka, Lawrence. Cons. Enar..... .61 Maiden Lane. New York. N. Y. Addison, Herbert, V.P.. Big Horn Collieries Co ,412 Colorado Bldg., Denver, Colo. Adkemn. J. Carson. Min. Engr.. HY Grade Manganese Co., Inc..Woodstock, Va. Ady. Joseph Wesley. Jr.. Min. Enar., 314 Mining Exchange Blda., Colorado Springs, Colo. Affelder. William Lewis. Asst. to Pres., Hillman Coal & Coke Co. & Allied Companies. 2006 First National Bank Bldg.. Pittshurgh, Pa. Ameck, B. F.. Pres.. Universal Portland Cement Co. .. .210 South La Salle St., Chicago. Ill. Agabeg, Edgar C.. Cons. Min. Engr.. ..... .Evelyn Lodae. Asansol, E. I. R. Bengal, India. tAsar. William M.. Aest. Prof. of Geol.. Kirtland Hall, Yale Univ.. ... .New Haven, Conn. Agaeniz. Rodolphe L, Pres.. Calumet & Hecla Consolidated Copper Co. ...... .Boston, Mass. tAgens, William Holmes. District Mgr.. Traylor Engrg. & Mfg. Co., 362 I. W. Hellman Blda.. Los Aneeles. Cal.

Jan 1, 1928

By Joseph J. Yancik, Leonard L. Felts, George B. Clark

LITTLE information has been published concerning the actual or useful amount of energy obtained from explosives when they are used for blasting. To provide more data on this subject, 8-in. neet cement cubes were blasted in a steel plate box and the breakage energy evaluated by comparison with drop crusher results using Rittinger's,1,2 Kick's: and Bond's' theories. Theories by Bond and Wang," Lineau," Hatch,' Roller,' and others0-11 were not considered applicable. Those used in this investigation may be expressed mathematically as follows: Rittinger Theory E = KrS2, pet,—--------------- [1] 40 d1 d0 Kick Theory TV 1 1 E = =K, [S pct. log1/d+ 100 log d0] [2] 40 d1 L. L. FELTS, Junior Member AIME, was formerly a Graduate Assistant, University of Illinois. G. B. CLARK, Member AIME, was formerly Professor of Mining Engineering, University of Illinois, and is now Chairman, Dept. of Mining Engineering, Missouri School of Mines and Metallurgy. J. YANCIK, Junior Member AIME, is a Graduate Assistant, Missouri School of Mines and Metallurgy. This paper, TP 4213A. is revised from a thesis submitted by L. L. Felts in partial fulfillment of the M.S. degree in Mining Engineering, University of Illinois, 1954. Discussion may be sent (2 copies) to AIME before May 31, 1956. Manuscript, Dec. 27, 1954. Bond's Third Theory E = Kb [S pct. log1/d1+ 100 log d0] where E — energy used in breakage, d, = average diameters of screen fractions of broken cement particles, pct, = percent weight of diameter d;, and 2 pct, = 100 pct. The above equations were employed to determine values of Kr, Kk, Kb for particle size distributions similar to those obtained from the blasting curves. These values were in turn used as a means of approximating the specific energy of the blasted material. The efficiency of crushing by blasting was then determined by dividing this specific energy by the maximum available work of the explosive per gram of cement. Knowledge of the failure of solids under static loads is developing very rapidly. Their failure under impact loads has been investigated and reported in the literature only to a limited extent. Theories of failure' hnder static loading include 1) the maximum stress theory, 2) the maximum strain theory, 3) the theory of constant elastic strain, 4) theory of maximum shearing stress, and 5) Mohr's theory of strength. All of these have elements of usefulness in establishing an applicable theory for blasting. For highly strained and compressed material such as that surrounding a detonating charge of high explosive, the Mohr theory and its implications appear to be the

Jan 1, 1957

By E. W. Newman

DURING 1943 and 1944, there was an urgent need for certain grades of optical calcite (Iceland spar) for instruments for military uses. To find a supply of this material, prospecting was carried out in Montana, California and Colorado. Although some production was obtained by the work in California, the best results were from prospecting the large calcite veins of south central Montana. The bulk of the optical calcite mined during World War II has come from that area. The Bureau of Mines took an active part in the search for optical calcite in Montana. It examined most of the known calcite veins in the 70-mile distance between Wilsall, on the Shields River, and Absarokee, on the Stillwater River, and conducted exploration on several of the deposits. The Geological Survey also took an active part by mapping many of the veins. Actual mining of the calcite was performed at first by Calcite Operators, Inc., and later by the Metals Reserve Co., through an agent. A sorting plant was established at Clyde Park, where custom material could be sold. These activities stimulated mining by private operators. To be suitable for military uses, the calcite mined had to meet rigid specifications as to both size and quality. Individual crystals had to be clear and transparent and if in the form of rhombs had to measure at least 7/8 in. on each edge. Some color and a few inclusions in the calcite were allowable, but material with incipient or developed cleavages, or showing twinning other than parallel to the base, was unacceptable. HISTORY OF DEPOSITS The existence of large veins of calcite in south central Montana has long been known, and for many years the farmers of this region have used the common vein calcite for producing grit for chicken feed. According to reports, the first optical calcite produced from Montana came from the Cartwright deposit near Greycliff,1 but until recently the mining of optical calcite in Montana has been limited to spasmodic searching for small crystals suitable for making nicol prisms for saccharimeters and microscopes, or for mineral specimens. The possible need of substantial amounts of optical calcite for military uses began to appear late in 1942 and early in 1943, therefore the Polaroid company began searching for a source of supply in Montana and California. Work on the Wade property near Clyde Park was started on a small scale in the fall of 1942, by A. H. Hansen, of Clyde Park. During the winter and spring of 1943, a modest quantity of optical calcite was mined and shipped to the Polaroid Corporation, Cambridge, Mass. Most of this was produced from the "Hansen vug," which was found close to the surface. Early in the summer of 1943, mining on the Wade property was undertaken by Calcite Operators, Inc., a company organized for mining optical calcite from the Montana and California deposits. This com-

Jan 1, 1945

By Caner Zanbak

Deformational behavior of a rock mass can be modeled with a constitutive law based on theories of elasticity, and plastic and viscous deformation. For most rock types, such constitutive models may be used with confidence because there is no geochemical interaction between the rock-forming minerals and water. However, if volume changes in the rock due to geochemical phase transitions are predicted, then these volume changes must be converted into mechanical parameters and must be included into the constitutive laws. In this paper, geochemical phase transitions between anhydrite (CaS04) and gypsum (CaS04-2H20) will be brought to the attention of researchers in rock mechanics. Hydration of anhydrite to gypsum may yield volume increases up to 62.6 percent and dehydration of gypsum to anhydrite may cause volume decreases up to 38.5 percent. If one were to convert the volume increases in hydrating anhydrite into strains and calculates the required stresses to restrict the expansions, the magnitude of stresses will be found at GPa levels. Such stresses on swelling anhydrite layers cannot be provided by geologic media. Therefore, the host rocks will deform under these high stresses. On the other hand, under increasing stresses, geochemical transition of anhydrite to gypsum may stop after some hydration of anhydrite, and anhydrite and gypsum systems may become stable. Changes in temperature and solution compositions in the anhydritel gypsum system also control the stability of the geochemical system, and therefore, the extent of volume changes. A similar conceptual model can be drawn for volume decreases due to dehydration of gypsum to anhydrite. In this case, stress reduction on the gypsum layer may cause extensive fracturing and changes in the state of stress in the host rock mass.

Jan 1, 1984

By Ronald C. Koo

THE effect of grain size on the mechanical properties of the bcc metals has been a subject of intensive theoretical and experimental study.'-l5 Quantitative relationships have been established experimentally between yield stress and grain size and between the ductile-brittle transition temperature and grain size in a number of metals.6"15 Much significance has therefore been attached theoretically to the grain size dependence. In all these experiments, different grain sizes were always achieved by annealing specimens at various temperatures. The implicit assumption was that any change in the dislocation substructure or in the distribution of impurities which might occur simultaneously with the production of various grain sizes had only a negligible effect on the mechanical properties. The validity of this assumption, however, is questionable. transformation in iron-nickel alloys is actually an extraneous phenomenon due to inadvertent compositional changes in the martensite if the heating rate is not sufficiently rapid. This complication can be avoided by up-quenching for the reversal treatment,5 and then the stabilization does not appear. Clearly, the lattice imperfections and strengthening produced by the reverse transformation are not responsible for the marked stabilization which has been observed by other investigators in these alloys. Data will be presented in this note to show that, at least in recrystallized tungsten of commercial purity, the difference in the ductile-brittle transition temperature of specimens annealed at various temperatures is more a result of a variation in the distribution of impurities rather than of the difference in grain size produced by the anneal. Ductile-brittle transition temperatures in tension were determined on powder-metallurgy tungsten specimens recrystallized at various temperatures. Tensile specimens having a gage length of 1.50 in. and gage diam of 0.18 in. were recrystallized at 1450°, 2000°, 2350°, 2550°, 2750°, or 2800" for 30 min in a vacuum furnace at a pressure of 1 x 10"5 mm of Hg and then tested at a constant extension rate of 8 x 10 per sec in an argon atmosphere from 100" to 800". Typical quantitative analyses of impurities are given in the Table. These results show that, within the precision of the analyses, see Table, annealing did not result in any detectable change in the impurity contents of the specimens, nor was there any detectable difference in purity between specimens having large differences in grain size annealed at the same temperatures . The results of the tensile tests yielded three distinct ductile-brittle transition curves approximately 225' apart. As shown in Fig. 1, data of specimens annealed at 1450°C and those of specimens annealed at 2000°C (O) fell on Curve A. Data of specimens annealed at 2350" and 2550°C fell on Curve B, and those of specimens annealed at 2750" and 2800°C fell on Curve C. The decrease in ductility with increase in annealing temperature became so pronounced that one third of the specimens annealed at 2750" and two thirds of the specimens

Jan 1, 1963

By Ravindra M. Nadkarni, Milton E. Wadsworth

The kinetics of cetnentation of copper with iron were observed to follow first-order kinetics and increase with speed of agitation to a limiting value. Maximum rates agree closely with theoretical values based upon a model of aqueous solution diffusion through a litniting boundary film. Back reaction kinetics are shown both theoretically and experimentally to be independent of ferrous iron concentration in solution. The inlportance of attnospheres of air, oxygen, nitrogen, and hydrogen was studied and the results have been correlated with several impovtant oxidation processes involving metallic iron and copper. The kinetics of the reaction of ferric ion with metallic iron were found to be slow in the absence of metallic copper and essentially proportional to the surface area of metallic copper present in the system. THE precipitation of copper on iron is classic as an example of a relatively ancient art applied successfully for centuries with little fundamental understanding of the important parameters involved. There is some indication that the process has been a commercial means to produce copper since the sixteenth century.' The amount of fundamental work on the cementation of copper with iron is not great. Wartman and Roberson2 carried out a series of detailed copper cementation experiments using natural and synthetic mine water. The following were presented as the three principal reactions: Reaction [I] is the desired cementation reaction and accordingly 0.88 lb of iron would produce 1 lb of copper. In actual practice iron consumption would more normally fall in the range of 1.5 to 2.5 lb per lb of copper. Wartman and Roberson attributed the excess consumption of iron to Reactions [2] and [3]. They found that Reactions [I] and [2] proceeded at approximately the same velocity while Reaction [3] was much slower and would be diminished by controlling the contact time. It was also pointed out that increased agitation is beneficial in removing hydrogen bubbles and barren layers of solution at the iron surface as well as removing contaminants resulting from the hydrolysis of iron. Episkoposyan3 and Episkoposyan and Kakovskii4 studied copper and silver cementation on rotating iron disks in chloride solutions. The kinetics based upon a diffusion model were first order and varied linearly with surface area and with angular velocity raised to the one-half power according to the Levich equation. The experimental activation energy for both copper and silver was approximately 3 kcal per per mole. Excess iron consumption was found to increase with temperature. The rate of cementation first increased with increasing acidity and then diminished at high acid concentrations. sutolov5 has presented an excellent review of the Leach-Precipitation-Flotation (LPF) process including a discussion of copper cementation from an electrochemical point of view although few experimental results were presented. From voltage considerations he predicted that cementation should not be influenced by the concentration of ferrous iron in solution. He considered several secondary reactions including Reactions [2] and [3] and pointed out the importance of oxidation of ferrous iron to ferric with oxygen. In addition it was suggested that Reaction [2] was enhanced by the dissolution of metallic copper by ferric iron which in turn consumed excess iron by the cementation reaction, Eq.[1]. Cementation of copper on metals other than iron has been studied by several investigators but, as in the case of iron, the amount of fundamental work is not extensive. Bashkova and kovalenko6 and Bashkova7 studied the cementation of copper on indium from copper and indium sulfate solutions. The rate was found to be first order and to increase with acidity. This was associated with a decrease in potential (EIn — ECu) and the simultaneous reduction of hydrogen ions at low pH. The rate of cementation also decreased with increasing indium concentrations which was postulated to be due to the decrease in the rate of diffusion of the ions in solution. Below 97°C the experimental activation energy was found to have the unusually low value of 2 kcal per mole and was attributed to diffusional control. Above 97°C the rate increased suddenly and was explained as a change in the rate-controlling step to a chemical reaction. In Part I of this study Nadkarni et a1 .1 have reported on preliminary results obtained in a laboratory study of the kinetics of the cementation process. The rate was found to be first order, proportional to the surface area of the iron, and to increase with speed of stirring until a maximum rate was observed. At low stirring speeds the deposit was spongy and adherent. At medium speeds the copper peeled off in bright strips and at high speeds finely divided copper was produced and continually removed from the surface. The amount of excess iron consumed increased with speed of stirring and with temperature. The average experimental activation energy combining results from several types of iron was 5.8 + 1.6 kcal per mole suggesting diffusional control through a limiting boundary film. Traditionally copper cementation has been carried out over the centuries in gravity-fed launders of various design containing scrap iron. More recently rotating drum precipitators and activated launders8'10 have been used. In the latter, copper-bearing solutions are

Jan 1, 1968

[YEAR OF ELECTION 1913. FRANK DAWSON ADAMS Montreal, Canada 1938. HENRY CORT HAROLD CARPENTER London, England 1933. KARL EILERS New York, N. Y. 1922. FEDERICO GIOLITTI Torino, Italy 1906. SIR ROBERT A. HADFIELD London, England 1921. FRANK WILLIAM HARBORD London, England 1917. HERBERT HOOVER York, N. Y. 1939. HENRY KRUMB New York, N.' Y. 1921. C. McDERMID London, England 1913. EZEQUIEL ORDONEZ Mexico City, Mexico 1935. ROBERT PEELE New York, N. Y. 1938. A. M. PORTEVIN Paris, France 1937. JOHN V. W. REYNDERS New York, N. Y. 1937. GEORGE S. RICE Washington, D. C. 1911. ROBERT H. RICHARDS Cambridge, Mass. 1934. T. A. RICKARD Victoria, B.C., Canada]

Jan 1, 1940

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1936 arc available at Institute headquarters, unless otherwise noted They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTION Copies of the TECHNICAL PUBLICATIONS have been mailed to members of the Institute that are registered in the different classes A-Metal Mining, B-Milling and Concentration, C-Iron and Steel Division, D-Nonferrous Metallurgy, E-Institute of Metals Division, F-Coal Division, G-Petroleum Division, H-Industrial Minerals Division (Nonmetalhcs) , I-Mining Geology, L-Geophysical Prospecting Other members may obtain copies by writing to the Secretary Copies of CONTRIBUTIONS may also be obtained from the Secretary's office Additional copies are sold at the rate of 1 cent per page, minimum charge, 25 cents Non-members may purchase the papers to the prices mentioned

Jan 1, 1937

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Apr. 10 to May 10, 1915: William W. Elmer, Tuttletown, Cal. R. R. Freeman, Jr., Wollaston, Mass. Lawrence Addicks, Douglas, Ariz. Francis R. Pyne, Elizabeth, N. J. W. F. Durand, Stanford Univ., Cal. George B. Pickett, Ophir, Colo. S. P. Cooper, New York, N. Y. R. V. Norris has been elected President of the Columbia School of Mines Alumni Association. Robert C. Sticht has been elected President of the Australian Insti¬tute of Mining Engineers.

Jan 6, 1915

By AIME AIME

WILLIAM BAYARD HEROY, Director of the Institute since 1935 and Vice-President for the past year, has been active in both geological and engineering circles of the petroleum industry for many years. "Bill," as he is generally called, was born in New York City in 1883, and graduated from the department of geology at Syracuse University in 1909 with a Ph.B. degree. Immediately he joined the U. S. Geological Survey, where he established an enviable record during the next eleven years. While with the Survey he acted variously as chairman, chief, and advisory engineer for a variety of Governmental bodies, many concerned with power.

Jan 1, 1939

By H. M. Chance

Jan 1, 1886

By James E. Lawver

A SURVEY of Minerals Beneficiation Div. membership indicated genuine interest in automatic process control, but revealed that the average mill is operating with a minimum of self-regulating devices. Apparently, the mill operators are content to continue without controls until the practicality of self-regulating devices is more generally accepted, or, in the opinion of the writer, until automatic controls become a necessity to meet economic demands of product quality and cost. Both to stimulate interest in control, and to solicit publication of technical know-how by members and equipment manufacturers, this paper presents a cross section of control problems in two general categories: (a) Control problems that can usually be solved by reference to the literature, i.e. controls that have proven successful in the mineral or chemical industries; (b) Problems that are troublesome and frequently unsolved due to unavoidable adverse conditions in the mill circuit to be controlled.

Jan 10, 1953