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By R. B. Adair, J. S. Browning

The laboratory batch and continuous flotation pilot plant tests demonstrated the technical feasibility of recovering high grade mica concentrates from weathered mica pegmatite ores of Alabama and Georgia. The research indicated that combinations of anionic and cationic collectors may be used effectively for flotation of fine size mica from weathered pegmatite ores. In continuous tests, concentrates containing 98.5% mica were obtained from the Georgia pegmatite ore; the Alabama pegmatite ore concentrates contained 98.4% mica. The recoveries were 91 and 89% respectively. INTRODUCTION The principal uses of fine ground mica are as a filler in wallboard joint cement, as a filler and surface coating for roofing, as an ingredient in paints, and in oil well drilling mud. The mineral has other uses in the manufacture of rubber, wallpaper, plastics, welding rods, electric insulation, house insulation, and textiles, and as an annealing agent in metal treatment. In recent years, more than 99% of the domestic mica produced has been scrap and flake mica (mica which does not meet specifications for sheet mica and is used for producing fine ground mica). There has been a continued increase in mica production for several years, the 1963 production of scrap and flake mica totaling 117,251 tons.1 Ground mica is obtained primarily by crushing and milling pegmatites and schists. To a lesser extent, mica is produced as a byproduct of kaolin washing and feldspar and spodumene flotation operations. The processes used in recovering mica by crushing and milling pegmatites are generally simple, consisting of various combinations of alternate roll crushers and trommel screens that separate the mica and gangue at screen sizes coarser than 6-mesh. As these processes are designed to recover only coarse mica, high losses in the plant rejects are common. Large tonnages of tailings from the crushing and screening plants have been accumulated in a number of areas. Methods for treating such products were developed by the Bureau of Mines in 1941,2 but have not been generally applied. More recently, mica flotation research has been completed and published by the Bureau of Mines.3 These methods required complete removal of 150- to 200-mesh materials from the flotation feed with consequent fine mica losses. Later, the Bureau of. Mines investigated methods for-recovering fine size mica from pegmatite ores after desliming sufficiently to remove clay materials, but not so drastically as to remove the fine sands. This report summarizes the results of these studies. The process developed was effective on pegmatite ores from two locations and should be applicable to the commercial treatment of other mica-bearing pegmatite ores and fine rejects that have been accumulated at various mica-milling operations. DESCRIPTION OF ORES The ores used in the investigation were obtained from the Dixie Mines, Inc., Heflin, Alabama, and the Ruberoid Corporation, Hartwell, Georgia. The sample from Alabama contained muscovite and quartz, with a high percentage of clay, and minor amounts of biotite, kaolin, limonite and tourmaline. The mica in the ore was essentially all minus 4-mesh in size and was free of attached mineral grains. The Georgia sample contained muscovite and quartz, with minor amounts of biotite, kaolin, and limonite. The mica in the ore, which was essentially all minus 4-mesh, was liberated. Petrographic analyses of the two samples are given in Table I. THE ANIONIC-CATIONIC MICA FLOTATION METHOD Previous investigators2,3 have reported that complete desliming of mica ores at 150- to 200-mesh was required prior to flotation with cationic collectors to obtain satisfactory selective separation of the mica from the other mineral components. Numerous tests were made at the Tuscaloosa Metallurgy Research Center to determine if some reagent combination could be used to selectively float finer size mica without complete desliming. The investigation led to development of a process using a simple reagent com-

Jan 1, 1967

By Albert J. McIntosh

With petroleum consumption declining temporarily after V-J day, the oil industry is urged to use this period as a kind of stopgap to rebuild its war-depleted inventories and help cushion the effect of this decline on producers and refiners. Higher inventories should be reestablished, since recent experiences have indicated that, by and large, the present inventories of crude oil are too low even with the tremendous current production available. The following analysis indicates that inventory levels could be built up to about 490,000,000 bbl. by the end of 1947, an increase of about 40,000,000 bbl. over the reported stock estimated for the war's end. If at the end of the war the military have some 20,000,000 bbl. on hand, this inventory will either be resold to the industry or certain demands that have been assumed to be met by industry will be supplied out of these military stocks, which would leave about 20,000,000 bbl. (net) to be built up from current production. For stock rebuilding the industry could use 10,000,000 bbl. of crude plus 10,00,000 bbl. of products, totaling 20,000,000 bbl. If this were spread over a year, this would mean 55,000 bbl. a day. By analyzing the average inventories held in a year with the total quantity of goods handled during the year, the following study and tables indicate how far the inventories should increase in the immediate postwar period. Introduction For the period immediately following V-J day, most of the petroleum economists have forecast a considerable decline in the total consumption of petroleum and its products in the United States. This will be caused by the elimination of most of the military demands and the inability of civilians to immediately replace automobiles, burners, etc., and thus increase their requirements to make up for the military decline. When the automobile industry has been back on full production for two or three years, civilians will be able to consume much larger quantities of gasoline. Delay in the manufacture of new oil burners and the time it takes to construct new homes, adds up to the same story for distillate fuels. In reviewing this outlook, the question has arisen whether the petroleum industry should not use this period of lower consumption as a kind of stopgap to rebuild its war-depleted inveritories and help cushion the effect on producers and refiners of this sudden drop in requirements. Some persons have indicated that hundreds of thousands of barrels a day could be used for this purpose extending over a year or more. Refineries will be in existence, which could run over 5,000,000 bbl. of crude oil a day and crude-oil production might be running 600,000 to 700,000 bbl. a day above the demands now forecast for the period after V-J day. Reasons for. Making Inventories In order to plan intelligently for this period, the petroleum industry should determine the needs for the establishment of higher inventories for crude and petroleum products than have been carried during the war. The reasons for trying to make such a determination are as follows:

Jan 1, 1945

By Eugene P. Pfleider, Claus Freyberger

Generally, the different methods of financing new mining projects are not well understood by the engineers and supervisory personnel. Nor are the effects of these alternatives on depletion, taxes and profitability readily apparent to even the sophisticated management personnel without the aid of cash flow studies. Fortunately, with the advent of the computer it is possible now to simulate many different combinations of 1) equity, 2) loan and 3) production payment financing with little effort. A general computer program for cash flow analysis of mining ventures has been developed and applied as a case example to a 1967 feasibility study of the Underground Mining of Minnesota Taconite. The effects on profitability as measured both in rates-of-return and present value are presented for various financing combinations. In addition, percentage depletion rates were altered so as to measure the impact of this statuatory allowance. Based on the cost data as presented in the aforementioned 1967 feasibility study, and assuming 7% loans, the rates-of-return vary from 9. 9% to [00] % on equity variations and from 9. 9% to 11.4% on total invested funds.

Jan 1, 1969

By Y. Mishima, R. Shiromizu

THE equilibrium y phase in Cu-Be alloys forms by discontinuous precipitation, the new phase nucleating at the grain boundaries and growing into grains on both sides of the boundary. When the alloy is aged above 500°C, however, growth may take place into only one of the grains.1'2 In A1-Ag alloys it is known that the precipitate has the same orientation as the grain in which no growth takes place.3, 4 This was confirmed in the present investigation on a Cu-Be alloy. A Cu-1.79 wt pct Be alloy was solution-treated at 810°C for 2+ hr, quenched into water at O°C, and aged at 600°C for 1 hr in a salt bath. The specimen was thinned by chemical polishing and electropolishing at room temperature in a solution of H3PO4 saturated with CrOs. The foil produced was examined in a JEM 150 electron microscope operating at 150 kv. Fig. 1 shows precipitates growing on only one side of the grain boundary. The black platelike precipitates were identified as the y phase. Electron dif-

Jan 1, 1969

By Lucien Eaton

IN anticipation of a shortage of labor for hand-tram-ming at the Cliffs shaft mine of the Cleveland-Cliffs Iron Co. at Ishpeming, Mich., early in 1923 three 4-ton Goodman storage-battery locomotives, equipped with Edison batteries, were purchased. Storage-battery locomotives were chosen for this work because the expense and time required to put up trolley-wire and to bond the rails of the complicated system of tracks on the levels, where the locomotives were to be used, would not have been warranted by the amount of ,ore to be handled. The only changes in the tracks necessary for storage-battery locomotives were new switches and extra ties and braces on curves. The tracks were 24-in. gage, and were laid with 20-lb. rail. Edison batteries were chosen, because it was desired to charge the batteries from the trolley circuit already, in the mine, and this would have been impracticable with lead batteries. Each locomotive is equipped with 126 A-4 Edison cells, which are charged in series from the 240-volt trolley circuit while the trolley locomotives are running; and are discharged in parallel in two banks of 63 cells each. These locomotives were so successful that later 5 smaller locomotives, weighing 11/2 tons each, were pur-chased for use e with cars that are filled by hand and on levels where the amount of ore handled is small. These locomotives, built by the Geo. D. Whitcomb Co. of Rochelle, Ill., are equipped with batteries of 40 A-4 Edison cells each, the cells being the same as those, on the larger locomotives. They are charged from mer-curial-are rectifiers. These locomotives are operated by the trammers themselves, and have not special oper-ators like the larger machines. The trammers are all young men of American birth, and take quickly to the operation of machinery, and the simplicity of the con-trol on these locomotives has made special training unnecessary. A survey of the results was made by the A. C. Nielsen So., an excerpt from which follows: Eight Edison-equipped battery locomotives are now in use at an Ishpeming mine of the Cleveland-. Cliffs Iron Co. This equipment was installed to take the place of men who formerly pushed loaded cars by hand. Results have been very satisfactory and the de-pendable, trouble-free operation of the Edison batteries is considered to have been an important factor in the effectiveness of the new hauling method.

Jan 3, 1927

[For the year ending February, 1936 PRESIDENT AND DIRECTOR HENBY A. BUEHLER3 ROLLA, Mo. PAST PRESIDENTS AND DIRECTORS FREDERICK M. BECKET1 NEW YORK, N. Y. HOWARD N. EAVENSON2 PITTSBURGH, PA.]

Jan 1, 1936

OFFICERS AND DIRECTORS For the year ending February, 1932 PRESIDENT ROBERT E. TALLY JEROME, ARIZ. FREDERICK W. BRADLEY SAN FRANCISCO, CAL. WILLIAM H. BASSETT,P WATERBURY, CONN KARL EILERS NEW YORK N. Y.

Jan 1, 1929

OFFICERS AND DIRECTORS For the year ending February, 1934 PRESIDENT AND DIRECTOR FREDERICK M. BECKET NEW YORK ,N . Y. PAST PRESIDENTS AND DIRECTORS ROBERT E. TALLY JEROME ARIZ SCOTT TURNER WASHINGTON D. C.

Jan 1, 1932

R. W. NEWCOMB,* New York, N. Y. (written discussiont).-On page 1638 mention is made of a new -instrument with an exceptionally high resistance that has been developed by Charles Engelhard. All friction and wear of moving parts of the moving system has been elimi-nated by replacing the hardened steel pivots and jeweled bearings, commonly used on other instruments, by a double metallic filament, one at the top and One at the bottom, under slight tension. Any pos-sible distortion of the moving coil, because of tension, has been eliminated by introducing a solid spindle as the axis of the coil between the points on the coil where the metallic filament is attached. The filaments serve not only as a support for the moving coil; but also to lead in the current from the binding posts to the moving coil, and as a source of counter-torque; instruments so constructed, do not require leveling, and are mechanically very robust. The clock of the recorder serves only to drive the chart at its specified rate and -to operate a small contact-making device; i.e., there is no other mechanical load on the clockworks. The contact-making de-vice is so constructed that there is a quick-make, a quick-break, and a wiping effect while the contact is being made. Contact surfaces on this switch are of platinum platinum-iridium. The operation of this contact, which occurs once each minute, sends a current, from a 6-volt supply; through a solenoid magnet, which operates the depressor bar mechanism in the case of the single-record instrument; in the case of the multiple-record instrument, it operates the automatic switch and color-changing features, as well as the depressor bar.

Jan 12, 1919

A MINING institute open to all men interested in any branch of the mining industry will be held at the Col-lege of Mines, University of Washington, Seattle, during the week beginning March 5. Prospectors, miners, mine owners, persons interested in metallurgy, investors in min-ing enterprises, and the public generally are invited to at-tend. This institute will take the place of the Winter Min-ing Session which originated at Seattle in 1897 and con-tinued for twenty-eight years. The complete new equip-ment of the Mines Laboratory will be used to give demon-strations of new machines and processes of mining, ore dressing, and metallurgy. This year the ceramic industry, including cement and branches of clay working of special Importance in the Northwest, will be included in the insti-tute. All instruction will be given by specialists. Prominent technical men and managers will give lectures on their special subjects. Among the speakers engaged are G. T. Jackson, formerly superintendent of the Alaska-Gas-tineau and the Chichagof mines, who will speak on the mining of large bodies of low-grade ore; R. F. McElvenny, superintendent of the Tacoma Smelter, on the nature of contracts that a smelter can offer to mines and prospects; M. D. Leehey, mining lawyer, on some popular errors re-garding the mining law; H. H. Townsend, on the explora-tion and purchase of prospects by operating companies; J. L. McAllen, on quartz mining in the Willow Creek dis-trict, Alaska; F. Powell, on gold dredging. In the evenings, lectures illustrated by stereopticon views and moving pic-tures will be given. The week will close with an excursion o mines and plants.

Jan 3, 1928

By A. W. Faheneald, Lewis S. Prater

By taking advantage of the fundamental difference between screening and classification—namely, that specific gravity has no effect on screening but is one of the important factors in classification—a combination of the two may be used as a process of mineral concentration. Although this fact is not new, so far as is known it has had little or no commercial application. The scheme is not presented now as a process for producing finished products but rather as a preliminary operation rejecting part of the barren material from an ore before it is subjected to more costly treatment. That is largely the function of the new heavy-media concentration processes that have been widely accepted. Original installation costs for the present sink-float processes are relatively high, however, which confines their use to operations where large tonnages are handled. Sink-float has been successful on only the relatively coarse (approximately plus 10-mesh) portion of an ore, and it is in this same range that classification screening can function most satisfactorily. Theoretically, there is no upper limit to the size of particles that can be handled in a sink-float operation, but the degree of liberation in the very large pieces usually limits this. With classification screening, particles from % to % in. would be the largest that could be handled, but the lower range could be extended somewhat below 10 mesh. In order to take full advantage of the difference in specific gravities of the minerals being separated, sorting in the classifier should be under as extreme hindered-settling conditions as possible. Laboratory tests have been made on a galena ore and on an artificial mixture of quartz and magnesite to determine the separations that may be expected. Although more than one scheme may be followed, in these tests the separations were made by cutting the underflow from the classifier as a concentrate and then screening the overflow. The screen oversize was rejected as a tailing. Classification was done in a hindered-settling teeter column and screening was done by hand, using the standard 4 2 series. The accompanying flowsheet gives the testing procedure followed.

Jan 1, 1947

By A. W. Faheneald, Lewis S. Prater

By taking advantage of the fundamental difference between screening and classification—namely, that specific gravity has no effect on screening but is one of the important factors in classification—a combination of the two may be used as a process of mineral concentration. Although this fact is not new, so far as is known it has had little or no commercial application. The scheme is not presented now as a process for producing finished products but rather as a preliminary operation rejecting part of the barren material from an ore before it is subjected to more costly treatment. That is largely the function of the new heavy-media concentration processes that have been widely accepted. Original installation costs for the present sink-float processes are relatively high, however, which confines their use to operations where large tonnages are handled. Sink-float has been successful on only the relatively coarse (approximately plus 10-mesh) portion of an ore, and it is in this same range that classification screening can function most satisfactorily. Theoretically, there is no upper limit to the size of particles that can be handled in a sink-float operation, but the degree of liberation in the very large pieces usually limits this. With classification screening, particles from % to % in. would be the largest that could be handled, but the lower range could be extended somewhat below 10 mesh. In order to take full advantage of the difference in specific gravities of the minerals being separated, sorting in the classifier should be under as extreme hindered-settling conditions as possible. Laboratory tests have been made on a galena ore and on an artificial mixture of quartz and magnesite to determine the separations that may be expected. Although more than one scheme may be followed, in these tests the separations were made by cutting the underflow from the classifier as a concentrate and then screening the overflow. The screen oversize was rejected as a tailing. Classification was done in a hindered-settling teeter column and screening was done by hand, using the standard 4 2 series. The accompanying flowsheet gives the testing procedure followed.

Jan 1, 1947

By A. W. Fahrenwald, Lewis S. Prater

BY taking advantage of the fundamental difference between screening and classification-namely, that specific gravity has no effect on screening but is one of the important factors in classification-a combination of the two may be used as a process of mineral concentration. Although this fact is not new, so far as is known it has had little or no commercial application. The scheme is not presented now as a process for producing finished products but rather as a preliminary operation rejecting part of the barren material from an ore before it is subjected to more costly treatment. That is largely the function of the new heavy-media concentration processes that have been widely accepted. Original installation costs for the present sink-float processes are relatively high, however, which confines their use to operations where large tonnages are handled. Sink-float has been successful on only the relatively coarse (approximately plus 10-mesh) portion of an ore, and it is in this same range that classification screening can function most satisfactorily. Theoretically, there is no upper limit to the size of particles that can be handled in a sink-float operation, but the degree of liberation in the very large pieces usually limits this. With classification screening, particles from 3/8 to 1/2 in. would be the largest that could be handled, but the lower range could be extended somewhat below 10 mesh. In order to take full advantage of the difference in specific gravities of the minerals being separated, sorting in the classifier should be under as extreme hindered-settling conditions as possible. Laboratory tests have been made on a galena ore and on an artificial mixture of quartz and magnesite to determine the separations that may be expected. Although more than one scheme may be followed, in these tests the separations were made by cutting the underflow from the classifier as a concentrate and then screening the overflow. The screen oversize was rejected as a tailing. Classification was done in a hindered-settling teeter column and screening was done by hand, using the standard [v2]series. The accompanying flowsheet gives the testing procedure followed. [ ]

Jan 1, 1945

By Barnabas Bryan

In the year 1875, the Pennsylvania Supreme Court, acting on incorrect information concerning the production of oil and gas, established what has become the law of the land for the governing of oil production. While the decision was ideal for the refining monopoly which was completed in that year, there is no evidence that the court was in any way influenced by that refining monopoly. The evidence indicates that the court accepted the view of the royalty owner and independent oil producer. Throughout the life of the refining monopoly it accepted this law, which was so evidently to its advantage in securing cheap raw material. The same policy continued until the development of the exhaustion theory and the entry of the various units of the former monopoly into the production of crude oil. It is curious that no one doubted the new theory of shortage sufficiently to feel the need of changing the law. When the theory entered the economic field sufficiently to raise crude oil prices beyond justification it shortly disproved itself, but by this time the question of split ownership in producing fields made a change from legal error to justice too complicated to be undertaken by the large companies. Not even the ardent advocate of unit operation dared to carry the question to the United States Supreme Court, which has never been asked to pass on the complete question. The impossible position of the producing industry, hemmed in on one side by court law compelling wasteful production and on the other by the national law against cooperation, lasted until the demoralization of 1927 led to cooperation within a state and under state guidance. Since that time control of production has grown with the bringing in of each new field and at this time has the active support of the Department of the Interior in such ways as are definitely legal. As in 1875, the royalty owner and independent producer are opposing by all possible means the rational conduct of the business of producing crude oil. Fluctuation in Investments The investor in oil securities has not been as badly fooled as has the oil man himself. Fig. 1 is designed to show the composite regard of all

Jan 1, 1930

By Robert L. Clayton, Arthur Baker

Two massive sulfide zinc-copper ore bodies are in quartz-sericite schist (probably formed by regional metamorphism of sediments) and andesite of the Precambrian Yavapai Series, on opposite sides of a large rhyolite mass. The Copper Queen ore body is conformable with bedding of its schist host rock, but the Old Dick ore body probably crosscuts the strata. A lens of low-grade mineralization in chlorite schist, associated with the Old Dick ore body, crosscuts through 150 feet of strata. The ore bodies are almost entirely enclosed by premineral faults with less than 150 feet of displacement. The minerals of the ores are pyrite, sphalerite, and chalcopyrite, with minor arsenopyrite and galena and small amounts of intimately associated chlorite, sericite, and calcite. Old Dick sphalerite-chalcopyrite intergrowths have mutual boundaries, and sphalerite grains contain abundant exsolved chalcopyrite. Copper Queen sphalerite-chalcopyrite intergrowths have extremely ragged boundaries, the sphalerite contains no exsolved chalcopyrite, and the ore overall has a schistose texture. The pre-mineral fault on the hanging wall of the Copper Queen ore body has had 100 feet of post-mineral displacement. Wall rocks of the Old Dick ore body locally have been sericitized. Andesite and quartz-sericite schists for at least several hundred feet around both ore bodies have been chloritized erratically and contain traces of copper.

Jan 1, 1968

By John M. Kelly

This report covers the development, exploratory drilling, and production of oil and gas in New Mexico during 1945. The statistical information was gathered from state regulatory agencies and other sources believed to be reliable; it is presented here in combined form for general information only, and the author assumes no responsibility for its accuracy or completeness.

Jan 1, 1946

By Hjalmar W. Johnson

It has long been accepted that blastfurnace practice varies to some degree with the coke used. While the qualities desirablc in iron have been known for some time, the qualities in coke that produce such iron have not been established. There are no objective standards for blast-furnace coke, which is usually described in general terms, as good or bad. Many experienced operators believe that coke cannot be measured objectively except by using it in the furnace, noting the result, and labeling the coke according to furnace operations. This is admittedly unscientific, and besides is useless for the two main purposes for which a measure of coke quality is needed: (I) to produce the best possible coke from the coals and equipment on hand; (2) to test new coals and determine their value for blast-furnace coke. In seeking such an objective measure, much work has been done on tumbler tests, shatter tests, sizes of coke, porosity, specific gravity, reactivity or combustibility and other tests, but as yet very little has been published in which conclusive correlations have been established between such objective measures and furnace operation. In our study of the problem during the past 8 years we have developed no new measures of coke quality, but we have collected data that are presented here in the hope that they may assist in further work, so that at some future time there may be developed such positive measures. The purpose of this paper is to show that there are variations in coke and that such variations do influence the operation of blast furnaces. At the same time we must remember that there are variations in blastfurnace operation and it may be the blast furnace that is at fault. This correlation of coke properties with blast-furnace operation will be worked out in the following steps: . Discussion of a period when a change in the coke resulted in an increase in efficiency on one furnace and a decrease in efficiency on another. 2. Adaptation of the inefficient furnace to the available coke so that normal efficiency was restored. 3. The use of radial distribution: a discussion of the effect of size of ore layer in adapting blast-furnace operation to the coke. 4. An example of a change in size of coke and the detrimental influence on the pro duction of one furnace. 5. An example of a change in size of coke, together with manufacturing data, to show why it changed, the conclusion being that coke is a product with an optimum value. 6. Illustration of the fact that coke has different optimum values on two furnaces, with discussion on adaptation of operation so the optimum values will be the same. 7. Limitations of the use of screen tests as an objective measure of coke quality. 8. Importance of uniformity in coke. Functions of Coke and Qualities Required to Perform These Functions Coke has three important functions in a blast furnace: (I) to furnish most of the

Jan 1, 1942

By Hjalmar W. Johnson

It has long been accepted that blastfurnace practice varies to some degree with the coke used. While the qualities desirablc in iron have been known for some time, the qualities in coke that produce such iron have not been established. There are no objective standards for blast-furnace coke, which is usually described in general terms, as good or bad. Many experienced operators believe that coke cannot be measured objectively except by using it in the furnace, noting the result, and labeling the coke according to furnace operations. This is admittedly unscientific, and besides is useless for the two main purposes for which a measure of coke quality is needed: (I) to produce the best possible coke from the coals and equipment on hand; (2) to test new coals and determine their value for blast-furnace coke. In seeking such an objective measure, much work has been done on tumbler tests, shatter tests, sizes of coke, porosity, specific gravity, reactivity or combustibility and other tests, but as yet very little has been published in which conclusive correlations have been established between such objective measures and furnace operation. In our study of the problem during the past 8 years we have developed no new measures of coke quality, but we have collected data that are presented here in the hope that they may assist in further work, so that at some future time there may be developed such positive measures. The purpose of this paper is to show that there are variations in coke and that such variations do influence the operation of blast furnaces. At the same time we must remember that there are variations in blastfurnace operation and it may be the blast furnace that is at fault. This correlation of coke properties with blast-furnace operation will be worked out in the following steps: . Discussion of a period when a change in the coke resulted in an increase in efficiency on one furnace and a decrease in efficiency on another. 2. Adaptation of the inefficient furnace to the available coke so that normal efficiency was restored. 3. The use of radial distribution: a discussion of the effect of size of ore layer in adapting blast-furnace operation to the coke. 4. An example of a change in size of coke and the detrimental influence on the pro duction of one furnace. 5. An example of a change in size of coke, together with manufacturing data, to show why it changed, the conclusion being that coke is a product with an optimum value. 6. Illustration of the fact that coke has different optimum values on two furnaces, with discussion on adaptation of operation so the optimum values will be the same. 7. Limitations of the use of screen tests as an objective measure of coke quality. 8. Importance of uniformity in coke. Functions of Coke and Qualities Required to Perform These Functions Coke has three important functions in a blast furnace: (I) to furnish most of the

Jan 1, 1942

By F. C. Miller

The metallurgical fuel of Colorado, Utah, and New Mexico has been a Veiny tardy member in the caravan of western industrial progress. The history of western coke has naturally been closely related to the development of the metallurgy of iron and steel and the precious metals, in the State of Colorado. It was at Leadville, with a population of 300 in 1877, that the Sentinel was published by Richard S. Allen. The Sentinel gave very full accounts of the various mineral discoveries at the new town of Leadville, which found their way to the more widely circulated journals of the East, and attracted the attention of many people. At the close of 1878, a census slowed a total of 5040 persons. The first smelter was established in 1877, at Malta, two miles from Leadville, by A. R. Meyer, but was not successful. It was succeeded by the Harrison Reduction Works, in 1878. The La Plata began with one furnace in June, 1878, and in 1879 had four furnaces in active operation. These furnaces used charcoal for fuel, and, because of hot tops, suffered a tremendous loss in lead and silver. This difficulty was overcome by the erection of 50 single-bank 10-ft. beehive ovens at Crested Butte, Colo., in 1880. The slack coal sent to these ovens was very pure, and yielded a coke carrying as little as 4.5 per cent. ash. Among the pioneers in the Leadville district were Grant, Eddy, James, Billings, Eiler, and Dickson. To these men the West owes the present expansion of its mining industry, and the erection of metallurgical processes for the treatment of precious metals. On Mar. 1, 1876, Pueblo was connected to the Atchison, Topeka & Sank Fe by the Pueblo & Arkansas Valley branch. The first smelter was erected in Pueblo by Mather and Geist. This modest plant grew into the immense Pueblo Smelting and Refining Co., now a part of the American Smelting and Refining Co. Coke for these small furnaces was made from unwashed Engleville coal, in 186 single-bank 12-ft. ovens at El Moro, in the Trinidad district, and it was not uncommon for the percentage of ash to exceed the percentage of fixed carbon in the coke. On Jan. 23, 1880, the Colorado Improvement Co. consolidated

Jan 1, 1920

Discussion of the paper of H. M. WARREN, A. S. BIESECEKER and E. J. POWELL, presented at the New York meeting, February, 1916, and printed in Bulletin No. 110, February, 1916, pp. 181 to 193. R.. V. NORRIS, Wilkes-Barre, Pa.-For many years the power requirements of breakers designed in the Anthracite. Region have been based on calculations made from indicator diagrams taken during operation, with various sections of machinery idle; these, while giving reasonably accurate figures, gave no intimation of the peak loads which have been shown so clearly in the paper. The high-speed flywheel for breaker rolls is new and shows a remarkable saving in peak power required, besides eliminating the stalling of the rolls from overload. The figures given are so far in advance of anything previously published that they will undoubtedly be used as a basis for future breaker design. It is to be hoped that the authors will continue this investigation and extend their paper by a description of the motors found best suited for this work. WILLIAM KENT, Montclair, N. J.-I notice on p. 187 reference is made to one of the difficulties being the starting torque, and it is proposed to use roller or ball bearings in order to decrease the high starting torque. I suggest that. before the roller or ball bearings are put in, an investigation be made as to the amount of the starting torque, as shown by wattmeter measurements and as to what the starting torque ought to be, theoretically, according to the energy formula; that is, how much starting torque is required to accelerate the rotating mass in a given number of seconds up to full speed. Having secured this information it may be found the amount to be saved by roller bearings is not very great. If it appears that roller bearings will not greatly decrease the starting torque, the next thing to be done is to have a special design of motor in which there is a field that can be made very strong at the start, by the use of extra poles or other means, and the next thing that may be done is to increase the speed from 10,000 r.p.m. to 25,000, which can be done with wire-wound flywheels, especially if the wires are made of vanadium steel.

Jan 5, 1916