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By J. R. Campbell

THE need for standardizing methods of arriving at definite conclusions regarding the cleanability of a given coal, and for measuring the performance of coal-cleaning equipment, is constantly increasing. Earlier notes by the author on this subject are amplified in this paper, because he believes that better preparation of bituminous coal is a partial solution of the coal operators' troubles. WASHABILITY STUDIES The term "washability" of coal was coined when washing was the universal method of separating coal from its impurities by utilizing their difference in specific gravity. This and analogous terms are still used in their broad sense although pneumatic or air separation is now used to clean coal. These terms are so used in this paper. Too much time or money, can hardly be spent on "feed surveys" to get a "picture" of the coal that is to be cleaned. There have been too many "rule of thumb" methods used. Screen analyses and "sink-and-float" tests on the raw coal enable the coal operator and washery man to predict within reasonable limits the results that may be expected from any efficient cleaning apparatus.

Jan 1, 1928

By Chu-Phay Yap

This is the second of a series of theoretical papers on the iron-carbon system. The solidus lines obtained as a result of the different methods of investigation fall naturally into three classes; namely, (1) a straight solidus originally suggested by Roozeboom and supported in the main by the work of Carpenter and Keeling, Andrew and Binnie, et al., using the thermal analysis method; (2) a slightly curved solidus obtained by Honda and his associates, using the magnetic and resistance methods: and (3) Gutowsky's solidus obtained by the Heycock and Neville method of quenching at successively higher temperatures. Although the thermodynamic method as shown in the first paper indicates that the straight solidus line is correct, no explanation has ever been advanced to account adequately for the disagreement in the shape and position of the solidus lines obtained. The nature of the solute in austenit.e is theoretically discussed. On the basis of such discussions, the data obtained by Honda and Endo on the change of magnetic susceptibility of steels with respect to temperature were critically subjected to a graphical analysis, which is shown to yield a rational explanation of the curved solidus lines.

Jan 1, 1931

Meeting of Jan. 23, 1914.-The President reported the appointment of Arthur S. Dwight and E. Gybbon Spilsbury as tellers to canvass the votes for the Annual Election of Directors. The President reported the appointment of the Committee on Precious and Base Metals, reorganized in accordance with the list on page xlvi. . The Treasurer was authorized to invest the sum of approximately $1,000, accruing from the sale of Life Memberships during the past year, by the purchase of one gold bond of the Interborough Rapid Transit Co., due 1966, at 5 per cent. The By-Laws of the San Francisco Local Section were approved. The recommendation of the Lord Kelvin Memorial Fund Committee that the balance of the fund unexpended be applied to the establishment of a Kelvin Gold Medal was approved. Forty-two members who had paid up all arrears of clues were reinstated. The sum of $100 was appropriated to the Columbia Local Section. The price of each of the three Volumes of Transactions of the year 1913 was established as $5 in paper and $6 in half-morocco. Forty-three Members, One Associate and four Junior Members were elected to membership in their respective classes.

Jan 2, 1914

It was a brilliant idea that suggested the formation of Local Sections of the Institute. The results in increase of membership and attendance at, annual meetings of the Institute have been very gratifying. Many different plans have been followed by the various Local Sections to interest members in the local meetings. It has been found to be almost necessary that the meetings be preceded by luncheon or dinner at some club or hotel where a suitable assembly room is available for the after meeting. Each Local Section has to work out its own type of meeting to suit its conditions. Like all human affairs, a great deal depends on the leader. Special attention should be paid to the qualifications of the Chairman and Secretary as these two officers have to shoulder most of the responsibility for the success or failure of the Section. They should be chosen, not so much on account of prominence in the profession as for their push and popularity with the local membership. It has been developed that in most Local Sections the meetings should not be more frequent than once a month with a vacation during the summer months.

Jan 7, 1919

The following resolution was passed by the Military Engineering Committee of New York on April 12, 1917. Copies are being sent to each member of Congress and to each of the five members in every State forming the committee representing, the five National engineering societies which carried on the industrial census under the direction of Howard Coffin. The Committee is urging every man to wire his Congressman and his Senator, asking him to do everything in his power to obtain favorable action by Congress on this resolution: Whereas in any large army to be created for the war, engineer troops will be needed in large numbers, and Whereas they should be officered by skilled engineers only, and Whereas the composition and training of such troops differ so much from the composition and training of non-technical troops that they should be organized under one central authority rather than under many scattered authorities. Now, therefore, be it resolved: That the members of the Senate and House of Representatives be requested to insist that all new units of engineer troops be organized and maintained by the War Department and not by the individual States.

Jan 6, 1917

ORE at the Jeffrey mine of Canadian John Mansville at Asbestos, Que., is hoisted by two 12 1/2 - ton capacity aluminum skips, counterbalanced. When the loaded skip reaches the surface it empties, via its sliding door, into a bin. Simultaneously, the skip tender, who operates at the 940 level, loads ore into the alternate skip from a 12 ½ -ton measuring pocket. This done, he sets the skips in motion. Problem: When moisture content of the asbestos ore is high, the ore, unknown to the skip tender, some- times sticks in the dumping skip, preventing complete discharge. Moreover, the sliding skip doors sometimes jam and stay open after the ore is discharged. If a skip in this condition is lowered, the result is either an overflow of ore, or the ore discharges through the open skip door, down the shaft. Spilled ore must then be mucked out of the spill pocket and hoisted in 2-ton cars. Cost is high, time is lost, and the shaft is sometimes damaged. Solution: A television apparatus was installed so that the skip tender might quickly spot improper door operation or hang-ups at the dumping station.

Jan 8, 1958

By Burt C. Mariacher

The Minerals Beneficiation Division meets each year at the Annual Meeting of AIME. All members are invited and encouraged to attend. For the information of those who did not attend the meeting in Denver last February, this column presents a summary of the reports given and topics discussed. Technical Committee Coordination Consolidation of technical programs having common interest to MBD and the Extractive Metallurgy Division is proving a considerable success, both on the technical committee level-through the efforts of the MBD-EMD Coordinating Committee-and in special symposia. MBD Chairman, R. S. Shoemaker, noted that J. D. Prater will be serving as Chairman of both the MBD Chemical Processing Committee and the EMD Hydrometallurgy Committee for 1970-71. R. P. Ehrlich commented on the cooperative effort of both divisions in organizing the Copper Metallurgy Symposium held at the Denver Meeting. This effort, he said, was important to the success of the Symposium. H. R. Spedden discussed inter-Division coordination activities on the SME level. The forthcoming MBD-M&E-EMD Joint Lead-Zinc Symposium is yet another example of progress in this direction.

Jan 1, 1970

By Charles Seastone

Location THE hydro-electric plant of the Peninsular Power Co., is located at what is commonly known as Lower Twin Falls on the Menominee River. This location is about 33 miles north of the city of Iron Mountain, Mich. The principal points of delivery of electric energy from this plant are in the mining regions adjacent to Florence, Wis., and Iron River, Mich., and in the cities of Iron River and Iron Mountain. The hydro-electric plant at Twin Falls and the substation of the Iron Mountain Electric Light & Power Co. are connected by a 6,600-volt transmission line carried on steel towers and steel poles, the latter being used within the city limits. The plant at Twin Falls and the substation at Iron River, about 36 miles distant, are connected by a 66,000-volt, duplicate, three-phase transmission line, supported on steel towers. At Iron River, are located a 1,500-kw. auxiliary steam plant, and the substation, from which the current is distributed to the mines in this vicinity. A description of the auxiliary plant, main and customers' substations, and of the main and secondary transmission lines, follows later in this paper.

Jan 2, 1915

As is known to representatives on Engineering Council, the Patents Committee of Council has collaborated with the similar committee of National Research Council in developing a scheme for the improvement of the method of dealing with patents in this country. The staff of the Patent Office is itself actively engaged in this effort. Out of the report prepared by the National Research Council, and approved and adopted by Engineering Council as the report also of its Patents Committee, remedial legislation has taken form. Three hills have been introduced, known as H.R. 5011, a bill to make the Patent Office independent of the Department of the Interior or any other department, and to simplify the procedure of the Courts with reference to assessment of damages or profits for infringement of patents; H.R. 5012, a bill to establish a single Court of Patent Appeals; and H.R. 7010, a bill to increase the force and salaries in the Patent Office. Chairman Charles A. Terry, of the Patents Committee, requests that representatives of Engineering Council write to their congressmen, urging the passage of these hills and so far as convenient, request their friends to do likewise.

Jan 9, 1919

By V. C. Wansbrough

A LUCID, thorough and powerful review of the impact of your tax laws on mining operations has already been presented by Granville S. Borden*. He has brought into focus and relief the pressure-points at which the shoe pinches most, has suggested some remedial measures, and enunciated much sound doctrine about the inter-relationship and interplay of taxation policy and mining activity. Under the heading "What Every Lawmaker Should Know", he laid down the fundamental proposition that "the magnitude of our mineral resources varies inversely with the magnitude of the taxes levied upon them." With this, as with his other major premises, all mining men must be in hearty concurrence. There can be no doubt that a flourishing and expansive future for the mining industry in this country, in Canada, or anywhere else will depend on the thoroughness with which these fundamental propositions are grasped by legislators, by national policy-makers and by public opinion at large. Coming to the specific points to which Mr. Borden has drawn our attention, I will touch on the corresponding provisions in Canadian federal tax law, by way of comparison and contrast.

Jan 7, 1950

By P. Barnes

(Read at the Philadelphia Meeting, February, 1878.) SOME statements have already been made to the Institute in reference to the cost of other departments of the above-named works, and some details have been given in tabular form.* For the purpose of the present paper it may be sufficient to say that this converting works is made up of three buildings, a cupolahouse, an engine-house, and a converting-house. The machinery and fixtures comprise two blowing-engines, two pressure-pumps, two five-ton converters, five hydraulic cranes, three pig-iron cupolas, four spiegel cupolas, two lifts for the cupolas, together with the usual arrangements of smaller parts. Every effort was made in the construction to combine efficiency of operation with durability, and the general course of the operation of the works during two and a half years seems to warrant the belief that the large outlay has been fully justified. • In the accompanying tabular statement all items on vouchers less than ten dollars, and all freight items have been omitted. * See Transactions of the. Institute, iv, 105, v, 427; also, Engineering and Mining Journal, vow. xxi, 561, xxiii, p. 439, xxiv, 419.

Jan 1, 1878

By M. S. Azun

The article unfortunately has some serious flaws negating the usefulness of the paper. The authors claim that kriging (linear kriging) is superior to other methods such as polygon. This is not the case. The deterministic methods (referring to polygon, ID, IDS, etc.) should not be compared with the statistical methods (linear kriging, disjunctive kriging, etc.) because they differ not only in their assumptions, but also their tools used in estimation. Thus, they give different results. By comparing the results of deterministic methods and linear kriging, the authors conclude that polygon, IDS, and linear kriging give an average thickness close to the value obtained from realizations. Besides, they argue that linear kriging gives less variance than the others [(fig. 2)]. The first conclusion is expected, due to the well-known central limit theorem. The second is the result of the statistical properties of different estimators. Thus, the comparison presented in the paper is rather meaningless because the authors have failed to follow basic statistical procedures. The numerical results of different approaches to an estimation problem cannot be generalized. In conclusion, the paper is not a meaningful contribution, and sadly, quite erroneous.

Jan 1, 1985

By Edward Walsh

The difficulty of securing for experimental research the actual conditions to be found in practice very frequently deters many from engaging in such work. Probably no metallurgical operation is more difficult to imitate in the laboratory than the blast-furnace process. So many complex reactions take place within the furnace, under such varied conditions of time and temperature, with innumerable mechanical, physical, and chemical mutations, that while the results reached may approximate those obtained in practice, there is always something wanting. Much work of this kind has, nevertheless, been done, and is now being undertaken. We are indebted to the bold minds who have attempted it for our present real knowledge of the blast-furnace process. Not that those who have performed series of experiments at a few given temperatures can claim the honor. It required more than this—the ability to make a summary of all preceding experiments, to supply those which were wanting, and to confirm those that were doubtful. Sir I. Lowthian Bell, whose able papers before the Chemical Society and the British Iron and Steel Institute (forming the basis of his great work, The Chemical Phenomena of Iron-Smelting) has

Jan 1, 1889

By F. P. Haver, M. M. Wong

When a mixture of chalcopyrite concentrate and lime is heated in air, the following reaction takes place: 2CuFeS2 + 4Ca (OH)2 + 8 ½ 02 ; 2Cu0 + Fe203 + 4CaS04 + 4H20. Ca (OH)2 is the only common reagent that will adequately control SO2 evolution in roasting. Other additives tried, including CaO, CaCO3, Na2CO3, NaOH, MgO, Mg (OH)2, and MgCO3, were not effective. All reacted with sulfur, but not to the extent that will be required to meet the new control regulations for sulfur oxide emissions. For example: when the concentrate was heated with the theoretical amount of limestone (CaCO3), about 55% of the sulfur was retained in the calcine; whereas use of the stoichiometric amount of Ca (OH), converted approximately 99% of the sulfur to CaSO1. In most of the experiments, Ca(OH)2 was formed by adding CaO to concentrates containing enough water to simulate filter cake from flotation circuit. This eliminated the need for drying the concentrate and utilized the heat of hydration of CaO.

Jan 6, 1972

By E. J. Hammer

Crushing and grinding of gypsum demands con- trolled processing to a fineness suitable for further treatment of the mineral into end products, and into various sizes of material which are themselves saleable products. The majority of gypsum tonnage ultimately ends up in stucco for wallboard. Therefore, mineral reduction is normally designed toward this end, but it is done in a manner that permits drawing off intermediate products to meet various customer requirements. This forces companies into compromises at times in equipment installations. Normally, 5 to 6 different sizes intermediate to the end product are marketed and these are generally the fineness of material to be used as stucco for wallboard. These sizes are produced by controlled crushing, grinding and sizing. How Ore Characteristics Guide Processing First, gypsum as a mineral (CaS0;2H,O) is number two on the Mohs scale two of hardness; only talc is softer, Despite being soft, gypsum is tough, a factor which is of critical importance when developing equipment specifications. In addition, of the increasing volumes of rock handled, the associated and included impurities such as anhydrite, silica or lime- stones are found to be relatively abrasive.

Jan 1, 1970

By C. M. Schwerin

It is often necessary to calculate the size of a hoisting-plant required to raise a given quantity of material, either as a preliminary to the detail design of the machinery, or to decide whether machinery on hand or offered by a manufacturer is adapted to the work to be done. The first element of the problem to be determined is the load to be raised. In a mine that is already developed, this is limited by the size of car that can be hoisted out of the mine and that will pass through the underground gangways. If these place no limits on the design, the size of the load will depend on the output desired per day, and on the number of hoists that call be made per day. The latter are fixed by the time required per hoist and the number of hours available for hoisting, after deducting from the working-day the time required for raising and lowering men, sending down supplies, and for the many small delays in handling cars. It must also be decided whether the hoisting is to be done in one shift or in all of them.

Jan 1, 1903

By T. V. Subrahmanyam, A. P. Rao

The adsorption behavior of chalcopyrite has been studied at different xanthate concentrations and flow rates in a column apparatus with potassium ethyl xanthate as the collector. Based upon the experiment results an equation of the type: 1/F = K3 + m3C + k2/t.Cm2.fm1 is proposed to account for the experimental data. Among copper minerals an early study on chalcocite by Gaudin and Schuman (Taggart, 1951) is well known for its research on the kinetics of the reaction by conventional method of mass balance between the products of reaction and xanthate consumed. The results were interpreted by the concept of ion exchange adsorption. Szeglowski (1977) conducted measurements on the adsorption of potassium ethyl xanthate on copper polarized to various potentials, the adsorption being measured by radio-tracer techniques. The adsorption in the range -1800 to 700 mv was found to be a reversible physical adsorption. The potential range in which the primary electrode process could lead to surface coverage with a minimum number of product layers was evaluated. The adsorption density of xanthate on sulfide surface was found to be related to the concentration of xanthate in solution and concentration of depressants as: [ ]

Jan 1, 1983

By M. H. Brady, J. G. Roscoe

Continental No. 1 This mine in Lisbon Valley has an orebody about 1200 ft long and varying from 250 to 70 ft wide. Average width is about 100 ft and stope heights average about 9 ft. It was developed by a 350-ft, 11º inclined shaft for trackless haulage, although a hoist and track are installed for auxiliary hoisting. Mining has been done from horizontal open stopes with random pillar support, using a HD5 tractor for mucking and a 4-wheel drive Gettman shuttle car for tramming. Slushers have been used to some extent in thin ore zones. Back support for stopes and haulage ways has been accomplished by rock bolts and landing mat. The most interesting feature of this mine has been pillar extraction. Mining was done under contract during the first year of operations with little regard for an orderly plan of stope layout or regularity of openings. Most of this work was done in the largest area of the orebody; consequently, pillar recovery has been accomplished under conditions which are far from ideal. However, a workable system has been developed which is competitive, both in cost and production rate, with open stoping.

Jan 7, 1958

By W. M. Morris

THE volumetric behavior of isobutane at temperatures below its critical temperature has been studied by several investigators. Seibert and Burrell1 measured the vapor pressure of isobutane from the ice point to the critical temperature. Dana and co-workers2 determined among other thermodynamic quantities the density of the saturated liquid and the saturated gas and the vapor pressure from approximately 0° to 130° F. Sage and Lacey3 studied a number of the thermodynamic properties of this hydrocarbon from 70° to 250° F. The specific volume in the gas and liquid region was determined at pressures up to 3000 lb. per sq. in. ? throughout this temperature interval. In addition, the vapor pressures were measured at 30° intervals. These data taken together serve to establish the thermodynamic behavior of isobutane at temperatures between 0° and 250° F. with reasonable accuracy. However, apparently there are no data available at the higher temperatures. For this reason an investigation of the volumetric behavior of isobutane at temperatures between 100° and 460° F. was carried out with apparatus that has been described in another paper (A.I.M.E. Tech. Pub. 1127).

Jan 1, 1939

ALTHOUGH it might seem more fitting to discuss this subject in the Ninth Book in connection with the smelting of iron where I had thought to treat of it in detail, this process of making steel appears to be almost a branch of the above chapter on iron itself; hence I did not wish to separate these two so far that they might seem to be [18v] different things. Therefore I wish to write of it here and to tell you that steel is nothing other than iron, well purified by means of art and given a more perfect elemental mixture and quality by the great decoction of the fire than it had before. By the attraction of some suitable substances in the things that are added to it, its natural dryness is mollified by a certain amount of moisture and it becomes whiter and more dense so that it seems almost to have been removed from its original nature. Finally, when its pores have been well dilated and softened by the strong fire and the heat has been driven out of them by the violence of the coldness of the

Jan 1, 1942