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APRIL 10-Officially, spring comes to the Great Lakes on March 21 as it does elsewhere in the country but in the Superior district continued snow and freezing until late in March have caused citizens in Duluth to place their bets on April 15 for the first ore vessels if the ice breakup is left to Mother Nature. North and west of Duluth and near the eastern end of the Mesabilies the little town of Aurora, population 1100. As the little v-nosed snowplow, pride of the community, shuttled back and forth clearing Aurora's few sidewalks, the crowd in Bradich's Cafe were more interested in the impending high school state championship basketball tournament in Minneapolis than in the outcome of Erie Mining Company's petition for water rights for their proposed 10 million ton taconite concentrating plant. Such a plant would employ 4500 workmen, and at the prevailing ratio of 10 people for every mine worker in Minnesota, this would mean a 45,000 increase in population for Aurora and the vicinity in the next few years. Downstate fishermen are alarmed at the flurry of activity by the mining companies in pushing plans for large scale recovery of iron from taconite. Inconvenience to these gentlemen will be inconsequential when compared with the vast increase in payrolls for range communities. Oliver is pushing the construction of a fine ore agglomeration plant at Virginia which will give them valuable experience for projected taconite processing. Oglebay, Norton & Co. is ready to go at Beaver Bay, north of Duluth, as the right of way for a railroad from Babitt to Beaver Bay is secured as well as permission to dispose of tailing into Lake Superior at the site of the proposed concentrating plant. This company is also doing research in agglomeration at Ashland, Ky., in cooperation with other interests. The financing is yet to be worked out. Of the four possibilities for agglomerating taconite concentrate-sintering, pellitizing, nodulizing and briquetting-the prospects for pelletizing appear the most favorable., It seems likely that 60 cents per ton can be saved by this process over sintering because only 1 to 2 pct of coal is required as compared with 7 pct for sintering. One reason for the lower coal consumption is that the chemical transition of magnetite to hematite which transpires in the pelletizing process is exothermic.

Jan 5, 1950

Beverley S. Randolph, Frostburg, Md. (communication to the Secretary): It has always appeared to me that each coalseam has its peculiar character or habit, due to the conditions of its formation, by virtue of which it is either persistent or variable in its section over extended areas. One seam will hold its thickness, chemical character, number and position of partings, beds of slate, etc., over a large area, while another will be found to vary in some of these characteristics every few feet. As the position of the outcrop is an accident of the topography, depending on folding and erosion which have taken place since the bed was formed, no one opening in the outcrop, or, in fact, anywhere else, can supply reliable evidence as to the general character of the seam. To determine the character of an untried seam, a number of sections are necessary from widely separated points, in order to show such variations as may exist. Should material variations be developed, more numerous sections are necessary, in

Jan 1, 1901

By Thomas T. Read

ONE of the major purposes of the Institute is to "maintain ... a library of books relating to subjects cognate to the sciences and arts of mining and metallurgy." In conformance with this purpose the Institute maintained its own library for a number of years until 1912 when it was merged with the libraries of the other Founder Societies. At that time the A.I.M.E.'s share of operating expenses was wholly covered by the income from a $100,000 gift from James Douglas. But interest on the Douglas Library Fund has declined from 51/2 per cent to 31/4 per cent; the library has grown from some 50,000 volumes in 1913 to more than 170,000 in 1945, with consequently increased costs; and its costs nave otherwise risen. The Institute today contributes to the library annually about 65c per member, of which about 25c is income from the Douglas Fund, or a net charge, from regular income, of 40c per member. The annual library budget runs about

Jan 1, 1946

By Henry G. Granger

A RESIDENCE of 14 years in the Republic of Colombia, spent in almost continuous traveling and prospecting-trips, has given me an intimate knowledge of the resources of that wonderful country. The man who best knows Colombia is unquestionably General Rafael Reyes, President of the Republic for the past three years, and with seven years more to serve in his present term. Such is the strength of his personality and the wisdom of his policies that his term of office will no doubt endure as long as he is willing to serve. The vastly improved economic situation and the brilliant outlook for Colombia are so directly due to the influence of President Reyes that a few lines concerning him. will not be amiss, if they serve towards a better understanding of his personality. Born of a distinguished ancestry in the mountains of Boyaca, he is now 57 years old, just the age of his friend Porfirio Diaz when be began the work which has placed Mexico in the rank of great modern nations. It was Reyes who came to Washington to protest against the action of the government of the United States of America in reference to the establishment of the Republic of Panama, and, without entering into a discussion of this affair, it can be fairly said that there was not an American in Colombia whose feelings of justice were. not outraged at the government action and subsequent refusal to submit the matter to the impartial judgment of the' Hague. President Reyes is an accomplished linguist, speaking English, French, German, Portuguese, Spanish, and Italian. He has a remarkably. powerful voice, which can readily be heard by a large assemblage. His height is about 6 ft., and his weight exceeds 200 lb. He has clear gray eyes. Reyes was the leader of those who favored the approval of

Sep 1, 1908

By Kennedy, Joseph E.

MANY things must be considered in coming to a decision as to what type of crushing and grinding equipment is to be used for preparing run-of-mine ore for concentration, amalgamation, flotation, or cyanidation. This paper is intended in no sense as a thorough discussion of these various factors, but rather contains a few observations based on a wide experience in the manufacture and application of milling machinery. One important governing factor is the tonnage to be dealt with. In large plants treating several thousands of tons in eight hours, a large jaw or gyratory crusher of substantial construction is standard equipment for reducing ore to 8 or 10 in. or finer. In open-pit work, using power shovels with 4- or 5-yd. dippers, a jaw crusher should have a receiving opening of 48 by 60 in., or 60 by 84 in., so that dynamite or hand sledging will not be required for breaking to a finer size before primary crushing. The coarsely broken ore is then conveyed by a belt to vibrating screens, the oversize from which is again conveyed by belts to secondary crushers having openings of 12 or 14 in., the product from which is conveyed to storage. From storage, the material goes to a finishing gyratory for reduction to 1/4 in. or finer.

Jan 1, 1936

By AIME AIME

MOST of us are far .from home, and yet our Japanese hosts- have made us feel very much at home. Here in the Orient we engineers are .learning a new meaning for the word "orientation"- hereafter that engineering term will be a synonym for gracious hospitality, and "to orient" will mean to turn a whole country over to the World Engineering Congress. Mere geographic distance is no longer able to separate nations, for the conquest of distance is one of the triumphs of 'modern engineering. We of the Americas are fortunate in the position of our continents: with their shores lapped by the waves of two oceans, we face' two great civilizations, the' Occidental and the Oriental, and thus we can share the intellectual resources of these two older cultures.

Jan 1, 1929

By AIME AIME

THE Board of Directors of the Institute has authorized the appointment of a committee to draw up rules of procedure under which awards can be made from time to time to petroleum engineers for outstanding contributions to the art of finding and producing oil and gas. These awards will 11e sponsored by the Petroleum Division and are the first recognition by any professional society of outstanding achievement in "oil mining." They will be in the form of either a gold medal, scholar- ship, or other suitable prize. The awards will be financed from the income of the Anthony F. Lucas Memorial Fund, which was started about fifteen years ago, shortly after' his death, by admirers of Captain Lucas.

Jan 1, 1936

By REED H. HYDE

IN these days of low metal prices and difficult marketing conditions, any treatment that will improve the grade of a product is of interest, particularly when the operation involves little or no addition to the total cost and may even result in a marketable by-product. Such a' combination of circumstances exists, in some cases, in the zinc industry, where it has been found that certain impurities can be removed from .the ore during the Dwight-Lloyd sintering operation, previous to reduction to metal. Consequently it is not surprising that zinc smelters having these sintering machines are paying particular attention to this phase of the operation. Loss of zinc as fume is very low under the conditions obtaining in sintering zinc ores, but impurities such as cadmium and lead are more readily fumed off and it is on this fact that the purification is based. As a result of preferential volatilization of these impurities a sintered product' is made from which purer zinc metal or oxide can be produced, while the fume may be collected and treated to recover the impurity metals. To be effective the operation must be carefully conducted, but no special equipment other than that of a well designed Dwight. Lloyd plant is needed.

Jan 1, 1931

By L. F. Reinartz

FROM the earliest times when our prehistoric ancestors laboriously fashioned crude tools and weapons from meteoric iron until our day when we manufacture steel in 150-ton open-hearth furnaces, the production of iron and steel has played a dramatic and important role in the development of civilization. Progress in the science of refining iron ore into iron and steel was painfully slow for many centuries. The keen scimitars of Damascus, the broadswords of the English knights, the coats of mail of French knights, and the Iron Pillar of Delhi are well¬known examples of medieval metallurgical technique. Expense and the scarcity of raw materials originally limited the distribution of iron and steel products. It was not until the nineteenth century that a determined effort was made to adapt the use of steel to peaceful pursuits. The spectacular and rapid strides made in the manufacture of steel during the last hundred years were hastened by the invention during the decade 1860 to 1870 of two great steelmaking processes-the Bessemer and the open-hearth process.

Jan 1, 1936

By Arthur A. Center

AT the beginning of 1944 it was expected that the production of metallic zinc in the United States from domestic and foreign concentrates would exceed the 1943 figure though domestic production of concentrates was expected to drop below the 1943 rate, mostly in the Tri-State area. Imports of concentrates were estimated to more than take care of such deficiency. North American concentrate production, available for import to the United States or elsewhere during the year, was estimated at over 200,000 tons recoverable zinc content; South American at about 65,000 tons; Australian at about 50,000 tons. Production of both concentrates and metal in the United States, however, did drop, attributable in considerable part to man-power shortage in the industry. However production exceeded consumption, which fell off, and stocks of metal increased. These stocks have increased since the middle of 1942 but production and consumption are coming nearer to a balance. The A, B, and C premiums, which have played an important part in keeping up domestic production of concentrates, extend only to the middle of 1945 by present legislation. Congress is being asked for their continuance during the war and

Jan 1, 1945

By HARRISON W. CRAVER

LIBRARIES are universally recognized as essential to modern civilization. In a world that gets most of its learning through the printed word, storehouses of print are a vital necessity. In this regard engineering differs in no way from the other learned professions, but until recent times the library needs of engineers have received rather scant attention. When the engineering profession was more of an art and less of a science than it is today, when each problem was solved more through the results of experience than by applying scientific principles, literature was less helpful. The engineer of today, however, is aware that his activities rest upon a scientific foundation and consequently comprehensive books dealing with more limited fields are now being published. Another difficulty for the operating engineer in the past was that the published works on engineering were written chiefly for use as college texts. A third obstacle to the development of engineering libraries has been the lack of librarians with experience in engineering.

Jan 1, 1938

By Paul Gemmill

Production was first recorded from the Pioche district in 1864, and it has continued to show an inherent ability to take on new life after periods of depression in the metal markets. Production from replacement leadsilver- zinc sulfide ore bodies in limestones of Cambrian age now accounts for several times the gross value of silver production from rich fissures in Lower Cambrian Quartzite. Aggregate production of some 6 million tons represents a gross value over $100-million. Future output is expected mostly to be from limestone replacement deposits of which the most productive are "channels" of ore up to several hundred feet wide and several thousand feet long with thicknesses from a few feet up to 50 feet. Such channels are restricted to the lowermost limestone bed of the district, about 250 feet above the basement quartzite. The "blotter-like" characteristic of this highly productive Jimesto~e bed in absorbing mineralization is believed to be, at least in part, due to lithology, including free carbon in the bed, which has created a unique set of conditions for delicately balanced mineralizing solutions that rejected any tendency to replace siliceous wall rock and were properly constituted for replacement of Limestone. All recognizable orogenic history is considered to be related to the Basin and Range faulting that created the mountain ranges. The faults developed after mid-Tertiary time and after widespread extrusives that are themselves involved in the faulting. Flat faults, formerly believed to be part of regional thrust faulting, are now interpreted as gravity slide faulting that can be shown to be large in magnitude and not simply local landslides. Large slide faults generally have concealed the great magnitude of mountain-bordering faults. Mineralization that accounts for ore is later than the faulting. Most faults are pre-mineral since they influence the shape of ore bodies, and some clearly have been offset by fault fissures containing ore. Post-mineral movement probably has been an important component of some large, initially pre-mineral faults. A single period of mineralization was begun by the introduction of large quantities of ironmanganese carbonate, and, in places, carbonate manganese with minor values in sulfides. Closely following the carbonate invasion, massive sulfides were brought in, usually replacing part of the carbonate body though in some places the massive sulfides replaced limestone that was not previously mineralized. Manganese mineralization is not a "halo" but leaks of manganese to higher formations and to the surface are the most significant exploration guides. The Pioche district is expected to be long lived with technological developments in ore treatment being important to the exploitation of low-grade manganiferous ores, while aggressive exploration is expected to find important quantities of bedded lead-silver-zinc ores of the massive sulfide type.

Jan 1, 1968

By W. J. Tait, A. E. Craig, E. P. McCurdy

C. M. Marquard—The problem of the automatic control of a grinding-classification circuit is not nearly as simple as has been indicated and it cannot be universally solved through the application of this device. The sound emanating from a ball mill such as the metallic clink of the balls against the liners can at times be misleading. The fact that the sound level due to the balls hitting the liners may be at a minimum does not necessarily mean that the mill is properly loaded. I have in mind an ore we treat that has a soft talcy gangue. The soft fluffy nature of this material makes the sound from the ball mill a most misleading parameter that is worthless as a means for controlling the amount of ore fed to the mill. In every milling plant there are transportation lags due to the time it takes the ore to travel from the mill bins to the ball mill. In many plants there may be several different transportation lags due to varying distances of bins from ball mill. These transportation lags can most seriously affect the operation of a controller. It has been found that under many circumstances the transportation lags can be so bad as to cause the controller to hunt seriously. Hunting can and in many cases does become so serious as to render automatic control impossible because of the surges it causes. While it is possible to compensate for this type of lag, this apparatus does not lend itself readily to accomplish the required compensation. Further, if there are groups of bins at various distances from the ball mill, compensation for one may not be sufficient or may be too great for another. Each milling plant presents a separate problem. The apparatus as presently described does not appear sufficiently flexible to accomplish this. It should be noted that the load on the classifier rakes is determined by measuring the current input to the rake drive motor. Variations in line voltage will

Jan 1, 1951

By E. P. McCurdy, W. J. Tait, A. E. Craig

C. M. Marquard—The problem of the automatic control of a grinding-classification circuit is not nearly as simple as has been indicated and it cannot be universally solved through the application of this device. The sound emanating from a ball mill such as the metallic clink of the balls against the liners can at times be misleading. The fact that the sound level due to the balls hitting the liners may be at a minimum does not necessarily mean that the mill is properly loaded. I have in mind an ore we treat that has a soft talcy gangue. The soft fluffy nature of this material makes the sound from the ball mill a most misleading parameter that is worthless as a means for controlling the amount of ore fed to the mill. In every milling plant there are transportation lags due to the time it takes the ore to travel from the mill bins to the ball mill. In many plants there may be several different transportation lags due to varying distances of bins from ball mill. These transportation lags can most seriously affect the operation of a controller. It has been found that under many circumstances the transportation lags can be so bad as to cause the controller to hunt seriously. Hunting can and in many cases does become so serious as to render automatic control impossible because of the surges it causes. While it is possible to compensate for this type of lag, this apparatus does not lend itself readily to accomplish the required compensation. Further, if there are groups of bins at various distances from the ball mill, compensation for one may not be sufficient or may be too great for another. Each milling plant presents a separate problem. The apparatus as presently described does not appear sufficiently flexible to accomplish this. It should be noted that the load on the classifier rakes is determined by measuring the current input to the rake drive motor. Variations in line voltage will

Jan 1, 1951

By W. W. Beddow

TWENTY years or so ago I wrote an article on management which consisted mostly of a chart similar to thousands of others of that day showing line functions, staff functions, and the chain of command in a typical mining organization. Since hen we have been "bossing" from the faces to the swivel chair and we have made many errors of no little expense to our companies. We have kept the chart in mind but many times we have changed the functions to fit the people we have had to work with. Good management after all is getting results with the people, the equipment, the supplies, and the natural conditions of the coal seam or seams and adjacent strata present. We have made, with little effort, a good showing with average people and equipment in good natural conditions. We have made a miserable showing (although expending every personal effort) with better than aver- age people and equipment in bad natural conditions. In the latter case many of our stockholders felt that better management would have found some way to save their investment. Perhaps they were right.

Jan 1, 1944

By Albert L. Toenges

COAL mining technique progressed slowly until the advent of mechanized mining. The cutting machine was a forward step, but had only a limited effect upon improving the percentage of coal recovery. Previously, the physical fitness of the loaders and the total output of the miners fixed mine production. The miner was an independent contractor and supervision over his working place was superficial. Rising costs and the inroads of substitute fuels demanded increased output per man to lower the unit production cost. Therefore, the amount of coal loaded mechanically in underground bituminous mines has risen from 0.3 per-cent in 1923 to 7.4 in 1929, to 20.2 in 1937, and to 48.9 percent in 1943. When loading devices were introduced it became necessary to adapt them to existing systems of mining, or to alter the mining system to fit the machine. An increased amount of supervision was required as output depended upon proper operation of the machine rather than on the physical fitness of the individual.

Jan 1, 1946

By S. W. MEALS

TWENTY million people in this country and Canada in nearly four million homes can give thanks to our Creator for natural gas, that most wonderful natural fuel with which Dame Nature has so bountifully blessed us. It is a clean, healthy and cheerful fuel, made up almost entirely of carbon and hydrogen. There is no residue, no waste and there are no objectionable constituents; an ideal fuel for the home. It operates like magic, open the valve and it is there for your needs, winter or summer, night or day. You are not required to place your order 30 to 90 days in advance and you do not need to pay for your winter's supply in advance. No ashes to worry about, no flues or chimneys to clean, nor kindling wood to store or bother the housekeeper. We who have been so blessed do not realize what it would mean to be without it. If in place of opening a valve we had to go to the woodshed or coalhouse and then build our fire-carry out the ashes-well, some of us I am afraid would be late reaching our offices and perhaps would miss our hot cakes for breakfast. One cubic foot of gas produced from the White Sand formation contains 1130 B.t.u. and weighs 47/1000 lb.; there are about 24,000 B.t.u. in 1 lb. of gas. Temperatures of over 3400 deg. Fahr. have been obtained with natural gas. Not only is it a superior fuel for the home but it has no equal for use in many large manufacturing industries, especially with the making of glass, pottery and open-hearth steel. In an open-hearth furnace, properly constructed, 5000 cu. ft. will melt one ton of steel. It requires 1/3 ton of bituminous coal gasified in a producer to do the same work, or about 40 gal. of tar or fuel oil, or 11,000 cu. ft. of by-product gas.

Jan 1, 1926

By C. H. Mathewson

UNFORTUNATE evasions of metals specifications recently brought to public attention through news items and editorials have caused executives of at least two great corporations to set up defensive procedures and to re¬affirm the patriotic purpose and conscientious effort of their plants in this battle of production. Whatever the exact conditions affecting these cases, in which the public interest has been safe-guarded by vigorous action, my reaction to such offenses in general is a feeling that they arise from the pressure and limitations that afflict our overextended war effort and that inevitably there will be more of them, doubtless more and more expertly conceived and less and less subject to detection as simple faked, or substituted analyses or tests. To the ladies, who doubtless are already beginning to ac¬quire a sense of painful resignation to a dry technical talk, may I say that the cookbook is full of specifications which customarily are varied within rather wide limits but it is generally recognized that the proof of the pudding is in the eating without regard to its exact composition or some scientific evaluation of its texture.

Jan 1, 1943

By C. E. Williams

THE Iron and Steel Division, A.I.M.E., is unique in this country in that it serves all phases of the iron and steel industries. Through its publications, its meetings, and its sponsorship of new technical developments in the industries, it has proved of great value. The various technical committees of the Division are the nucleus around which this service can be developed. The Blast Furnace and Raw Materials Committee has done excellent work. The need for beneficiation of iron ores is increasing and the economics of this operation are developing more and more in favor of increased activities. Ores that are slightly undergrade should be concentrated up to grade to supplant the present practice of mixing with higher-grade ores to bring up the average composition. Marginal ores that are not now being mined, or that are being mined and piled for future use, should be concentrated. The development of the use of sinter in the blast furnace, because of the elimination of fines, the advantage of better sizing of the charge, the resulting reduction of coke consumption, and increased output of pig iron per furnace, will make concentration and sintering become practical ahead of its natural time.

Jan 1, 1936

By M. D. Hassialis

THE object of a technical paper is to communicate new technical knowledge, the paper being the vehicle of communication and the existence of new knowledge its reason for being. It follows that the development of information worthy of communication, the criterion being novelty, is prerequisite to exercising the privilege of communication. The act of communication is achieved when the reader perceives the nature of the new knowledge, i.e., when he understands it. A paper achieving this objective is an acceptable technical paper. Development of new knowledge has as one of its purposes the increase of the existing state of knowledge and the enjoyment of the benefits derived therefrom. Technical knowledge is a collection of facts so ordered as to make apparent, relations existing between the facts. When the interrelations have been exposed the facts have been interpreted or explained Three broad, overlapping categories of technical papers may be recognized: papers consisting of (a) a report of facts, (b) an explanation of facts, or (c) a combination of a report and an interpretation. Ideally a technical paper should belong to one of the last two categories but current practice is to accept papers belonging to any of the three categories. Based on a small sample drawn from the scientific and engineering literature, the relative frequency of the three types is a: b: c:: 20:1:14. If the sample be limited to engineering literature, the ratios become a:c::2:1; type (b) being nonexistent. This large departure from the ideal is a consequent of the

Jan 1, 1948