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By Albert R. Ledoux

I am indebted to The Kaolin Co. of West Cornwall, Conn., and particularly to its engineer, Mr. M. Wanner, for permission to make public, through the Transactions of the American Institute of Mining Engineers, the interesting results of his experiments, having in view the winning of kaolin from deep deposits without shaft-sinking or removing of the overburden. So far as I am aware, nothing like it has been accomplished heretofore, although it reminds one of the methods successfully employed in Louisiana for the winning of sulphur from deep beds by the sinking of pipes one within another, injecting superheated steam under pressure through one pipe, the heat of the steam liquefying the sulphur and the pressure forcing it up through the other pipe to bins at the surface. The kaolin-deposit at West Cornwall is an alteration in situ— that is, it is not sedimentary. A series of clay-veins, dipping about 50" from the vertical, lie between a foot-wall of' limonite and a hanging-wall of gneiss and hornblende schist. The clay-veins alternate with veins or seams of more or less broken quartz, and unaltered feldspar. The deposit, which occurs at a point about 600 ft. above the Housatonic river, was opened five years ago, and about 5,000 tons of a superior grade of washed kaolin have been extracted from open pits, and sold. It soon became evident that this mode of extracting the product would prove unremunerative, by reason of the dip of the vein and the intercalary strata and lenses of quartz, and a more satisfactory method of working the deposit was sought. It is well understood that, in the preparation of all clays for market, especially residuary kaolin, the most important as well as the most difficult step is the washing of the crude product. The dificulties increaee with the percentage of foreign matter, especially quartz and mica, contained in the product. Hence, a system

Jan 1, 1907

By F. A. Emmerton

I have used for about two years, in the laboratory of the Joliet Steel Company, a rapid method for the determination of phosphorus in iron, steel, and ores, which possesses one or two features sufficiently novel to warrant description. In general, it is the method described by Mr. Benjamin B. Wright (Transactions, vol. x., p. 197), involving the precipitation of the phosphorus by means of molybdate solution, and its estimation in the yellow precipitate by reduction of the molybdic acid, and titration of the resulting oxide with a standardized permanganate solution, according to the principles laid down by Werncke (Fres, Zeit., vol. xiv., p. 1). In the use of this method, I had difficulty at first in obtaining a yellow precipitate of reasonably uniform composition. It is a well-known fact that, to secure this result, the conditions of precipitation must not vary. The principal condition is temperature; and acidity, concentration, proportion of nitrates and chlorides, and time, are important elements. I am aware that uniformity in these conditions has been obtained to a reasonable extent by many chemists,. so that they are enabled to use with success, methods based on the

Jan 1, 1887

By Arthur F. Wendt

The hot-blast oven of which the accompanying plate gives complete details, was designed by the writer for the spiegel-furnace of the Lehigh Zinc and Iron Co., at Bethlehem, Pa. Members of the Institute who visit these works will have occasion to notice the large amount of zinc-dust in the gases, and the consequent dirtiness of both the hot-blast and the boilers. The zinc collects in a crust on the iron hot-blast pipes and leads to the frequent burning of them. A large vertical standing-pipe stove, a modification of the "Pleyer," thus gave considerable trouble by the burning of pipes and, on one occasion, the toppling over of a whole row. These inconveniences are avoided in the hanging-pipe stove under consideration, and less heating-surface has been found to be required to heat the blast to a given temperature. The construction of the stove is so simple and so plainly shown in the plate that it is needless to enlarge upon it. Each pipe rests in a box and is connected by U-branches with the next adjoining pipes. An iron sleeve is placed around the joint and tightened, as usual, with iron filings. In case of a pipe burning out, that particular section is cut off by the valves and the sleeves are broken. The pipe is then readily lifted out of the box and a new one is substituted. The whole operation requires only a short time and the section can then be at once put into use. The boxes supporting the pipes cover the whole surface of the hot-blast and are closed by iron covers rammed with fire-clay. Owing to the air-space around the U-pipes there is little loss of heat in the upper part of the stove. Each section as built has 280 square feet of heating-surface. The furnace is blown by a horizontal engine with 46-inch stroke and 48-inch diameter of blowing-tube. At 28 to 30 revolutions, the engine delivers 3000 cubic feet of air per minute, at a pressure of 5 pounds. When five sections of stove are in use, the blast enters the furnace at a temperature of 850" F. That is, there are over two cubic feet of air per square foot of heating-surface heated to that temperature per minute.

Jan 1, 1887

By Byron W. Cheever

In my paper on the estimation of manganese, etc., presented at the Halifax meeting, in September, 1885 (Transactions, xiv., 372), I said that the colorimetric process "can never be made to give reliable results." This statement was based on the results of many trials made by my assistant, Mr. E. D. Campbell, and myself, following in our work the printed and oral directions of others, and such modifications as suggested themselves from time to time. The accuracy of the statement having been questioned, I have, since then, endeavored to find some method of conducting the operation which would give accurate results; I have also tried the methods used by five different chemists; and I am not able to bring the process within the limits of an exact method. While it can fairly be ranked with the colorimetric carbon-process, and can be used for checking the operations of a steel plant, yet it requires more care to obtain uniform results, and is liable to greater variations from slight causes than the carbon-process, and, in my judgment, is not a safe method to employ when exact results are sought.

Jan 1, 1887

By Richard E. Chism

The metric system is now in official use in the Republic of Mexico, having been adopted by the Government in the year 1862. Athough it is used to compute all customs and other duties to be paid to the General Government, in the measurement of public and private lands arid in all freight and other transactions on the railroads, and is taught exclusively in the public schools, the system has made but slight head way among the people,and has not succeeded in displacing the old-time weights and measures, which are still used in ordinary commerce. The latter were founded on old Spanish models, but, owing to the inexactness of the first standards and to subsequent changes, differ at present very widely from their originals. As to local modifications, weights are the same all over the Republic, but measures of the same name differ greatly in capacity in different States, and even in neighboring towns. The value in the metric system here assigned to each denomination of the old weights and measures is that fixed by the Mexican Government at the time of the adoption of the metric system. The equivalents in American weights and measures were calculated by me from data found in Trautwine's Pocket-Book as to the comparison between the French and American weights and measures, and are believed to be correct. I shall be thankful for early notice of any error that may be detected, that it may be corrected before the final publication of this paper in the Transactions. Linear Measures. Kilometers. Miles. 1 legua (league) = 5000 varas . = 4.19 2.604375 Meters. Feet. 1 vara (yard) = 3 pies.....= 0.83800 2.749578 1 pie (foot) = 12 pulgadas.....=0.27933 0.916526 Inches. 1 pulgada (inch) = 12 lineas . = 0.02328 0.916526 1 linea (line).......= 0.00194 0.076577 The vara is also divided (for dry-goods-selling) into palms or cuartas (palms or quarters). Meters. Feet. Inches. 1 palmo or cuarta .. .. = 0.209500 =0.687394 = 8.248728

Jan 1, 1887

By Ernest A. Hersam

Accurate ore-sizing with screens is drawing attention to certain details that now, more than ever before, require attention. There are many tests that must be preceded by careful sizing. The assayer often could profit by a more careful selection of screens. In milling, more attention is given the slimes produced. Cement-manufacturers are pulverizing and screening finer than they formerly did, and others are reducing materials to fine sizes at high cost, with screens used to govern the fineness of the pulverized product. Fine screens are expensive, easily injured by misuse, are carried in stock sparingly by most dealers, and are handled often by those who know little about them except their designated number. More attention, on the whole, needs be given the actual size of the mesh-openings, and less emphasis placed upon any custom or conventionality in numbering. An effort to classify wire screens, in this respect, leads at once into computations, where one is confronted with details of sizes and standards, of different wires, different gauges, and different customs. There is always uncertainty about the exact working-size of a screen until one gives the matter special attention, and devotes more time to it than its simplicity seems to demand. To know only the number is not sufficient for all uses. Often, in sets, superfluous sizes are used; and sizes are omitted that are of critical importance. In wire screens, the use of different standard sizes of wire makes important differences in dimensions that must be taken into account. The dealer usually grades screens by the number of openings per linear dimensions, regardless of the size of the openings or of the wire. Certain 100-mesh screens in use are found, by measurement, to be actually coarser than others of 90-mesh, a result which is due, of course, to the use of larger

Jan 1, 1907

By Edward Hart

Having occasion several years since to make ferrous sulphide, I attempted to do so by fusing a mixture of coal-brasses (FeS2) and dried ferrous sulphate. A very nice-looking sulphide was obtained; but on attempting to use it, I found that it was insoluble in dilute hydrochloric and sulphuric acids. The subject was laid aside at the time, but has since been taken up; and some curious results have been obtained, which I believe are new. I have made the material by all of the following methods and the product seems to be pretty much the same, however obtained : (a) FeS2 heated to fusion. (b) FeS2, and FeSO4 heated to fusion. (c) FeS2, and Fe2O3 heated to fusion. (d) FeS2, and FeCO3, heated to fusion. (e) FeSO4, and S heated to fusion. (f) Fe2O3 and S heated to fusion. Obtained in this way the mass after cooling breaks easily and is very nearly black in color. On the upper surface of the fused cake the color is generally reddish or brownish black. When this is treated with dilute sulphuric or hydrochloric acid, it refuses to dissolve; but if touched with the point of a file or any piece of wrought-iron, solution of the sulphide takes place with the evolution of sulphuretted hydrogen. If the iron is removed the evolution of gas ceases, and only begins again when the iron is again brought into contact with the fused sulphide. The same thing happens if the iron is connected with the sulphide by means of a platinum wire. But in all the samples of fused sulphide I have obtained, if the iron is allowed to remain in contact with the sulphide for a certain time (which varies with different samples of the fused sulphide) and is then removed, solution of the sulphide continues. Zinc, tin, and magnesium have the same effect as iron. In hydrochloric acid aluminium acts more rapidly even than iron. In sulphuric acid it has little if any effect. Copper in HCl, when brought in contact with the fused sulphide, dissolves quietly without evolution of gas. The solution of copper chloride formed becomes,as it flows down over the sulphide, converted into copper sulphide.

Jan 1, 1887

By F. G. Miller, E. B. Wilson

In 1972, coal mine productivity was in steady decline and labor and maintenance costs were spiralling upward. Yet, despite this sad state of affairs, nowhere in the US at that time was there a comprehensive and coordinated coal research and development plan in the offing. The Bureau of Mines had not yet been charged with such a responsibility, and industry was content to rely on machinery manufacturers for innovations. It was during this period that Bethlehem Steel Corp. determined that a new approach to coal mining research was needed for the industry as well as for the company itself. After studying Bethlehem's own mining practices, the state-of-the-art of mining research elsewhere, and development work by manufacturers, a comprehensive research package was presented to company management in late 1972. The ideas and experience of many operating and management personnel in the company contributed to the formulation of the final plan as approved.

Jan 10, 1976

By William Benzon

Bethlehem Steel's Cambria Division coal cleaning and preparation plant, operated by Bethlehem Mines Corp., is located in Cambria County, Pa., about 2 ½ miles southeast of Ebensburg. Here, above ground, is the most modern coal preparation plant in the world. Below the surface is a new coal mine also referred to as "the most modern that could be built today." The preparation plant has a capacity of 1370 tons of clean coal per hr. It serves three Bethlehem mines, Heisley No. 31, Revloc No. 32, and the new Cambria Slope No. 33.

Jan 12, 1965

By LeRoy Kienitz

There may be someone here who is not required to run his equipment at its maximum capacity. There may be some fortunate enough to have more crushers than needed, wider conveyor belts than required, and other mill equipment equally oversize. If so, then this paper will have no interest for him; but if most of you are in the situation we in the aggregate producing industry are in, then you probably wish to crowd your mill equipment to its limit. When you do this you must watch for block-up and overloads of all sorts. You need more eyes than you have to guard the critical points. The human eyes that now do nothing much, but watch should be freed for more productive work.

Jan 1, 1961

By Graham Walker

A new Code of Practice for the brake performance of off -highway vehicles was established in Alberta in 1976. Vehicles loaded to gross vehicle weight must be capable of stopping with mechanical brakes five times in quick succession on a grade of 10 per cent from a speed of 28 miles per hour. Comparative trials of various brake systems have been carried out and some combinations capable of meeting the Code are identified. Some problem areas in truck braking are reviewed and potential developments indicated.

Jan 1, 1977

By N. Staroselsky

"Significant energy savings are often possible for centrifugal compressors operating in parallel by improved control strategy and improved instrumentation. Blow-off can usually be reduced by improved surge control combined with a better control strategy for loading and unloading the group of machines. More precise and stable pressure control then becomes possible. This improved control strategy will also decrease the frequency of operation near the dangerous limits of surge or overload or overspeed. A sample station of mixed centrifugal and reciprocating compressors is examined and a substantial energy saving with the recommended control strategy is projected from operating data. Present Operating Conditions of the Compressed Air StationThe Compressor StationThe compressor station described here has three centrifugal compressors and three reciprocating. It supplies a mine in New Brunswick.Compressed Air and Power ConsumptionFigure I and Figure 2 provide graphs of air consumption and pressure changes based on the owner's data.During the typical two-shift operating day (Fig . I) in the non-productive shift (midnight to 8:00 a.m.), the consumption stays at a level of 9,000 SCFM. This corresponds to a pressure of 110 PSIG. Then, after 8:00 a.m ., the air consumption starts to increase and th e pressure decreases. Around 10:00 a.m., the consumption reaches its maximum level at 97 PSIG. Around II :30 a.m., the air consumption starts to decrease because of the production drop during the lunch break of the first shift. Pressure increases again up to 109 PSIG. After the break, consumption rises to its maximum level over 16,000 SCFM andpressure drops to 97 PSIG.Around 2:30 p.m., the air consumption drops sharply to 9,000 SCFM because of the production decrease to zero level. This drop results from changing of shifts. The pressure at this time increases again up to 110 PSIG. The second shift (2:30 to II :30 p.m.) is an alogous to the first.During the three-shift operating day, the break around 4:00 . a.m . and the shift change around 6:30 a.m. cause sharp drops in air consumption. The pressure for almost the entire night shift stays near 110 PSIG because the station is working with blowing-off even under the maximum consumption. The analysis of Figures I and 2 shows that the pressure varies with the air consumption changes. During non -productive time (non-production shifts , shift changes and breaks) or during the night shift, the total station capacity is proportional to the discharge pressure. By decreasing the level of this pressure up to 97 PSIG, the flow of the station may be decreased during the non-production time as follow s:"

Jan 1, 1980

By Norman O. Lotter

The problem of quantifying the full performance potential of an ore body in a concentrator, and how to configure a flowsheet to achieve that potential, either for a new operation or an existing one, is a strategic challenge. Modern flowsheeting technology that has been developed over the last twenty years has provided a suitable platform to achieve this. The integrated use of geology, compositional and quantitative mineralogy, sampling models, quality controls, and mineral processing, including flotation testing, has evolved into what is now called process mineralogy. Two specific tools have been developed and validated as standard methods in this toollbox. These are statistical benchmark surveying and high-confidence flotation testing. Both of these have borrowed from the sampling theories of Pierre Gy and from geostatistics. Additionally, they work on a replicate measurement and averaging basis, thus reducing the overall random error level. With this arrangement, one is in a position to characterize the ore from true samples and identify and quantify the economic minerals present in a manner that easily brings out the processing implications and likely grades and recoveries. In particular, the approach captures the variation in the ore body, which, if properly translated into the flowsheet design, minimizes the risk that unexpected responses will develop in the concentrator operations. A further advantage is that successful plant trials are now possible and practical. An overview of this approach is presented with two case studies.

Jan 1, 2011

By D. M. McFarland

IN mining, quarrying, and construction, drilling and blasting have an important influence on the operations that follow. If the fragmentation of material being disrupted is inadequate, loading and transportation equipment will not operate at or near full capacity. Any operator faced with this difficulty should not be satisfied until he is convinced by a careful study of his methods of drilling and blasting that no improvement can be made. Rock in a certain quarry in Ohio seemed to defy any grade of explosive or means of detonation that the explosives industry had to offer. The average result of a blast was that a great part of the burden would be pushed out from the face in a number of large sections that would jokingly be referred to as "boxcars." These were no credit to the explosives man and a costly problem for the quarry company. Such blocks retard shovel operation as they have to be uncovered and subjected to secondary drilling and blasting which, if extensive, is an expensive operation. It was an attempt to improve the fragmentation obtained in primary blasts that led to the development of milli-second-delay electric blasting caps. The reasoning that prompted the trial was that even with wide spacing of the drill holes it seemed that the burden was separated too quickly from the face by the cutting action of the explosives from hole to hole. If the time of firing of the holes could be regulated so that

Jan 1, 1948

By Denard Brandt, Isidro Martinez, Greg Baker, Laura Slattery, Teddy French

The Dos Pobres Mine is a copper oxide heap-leach mine located near Safford, Arizona. Mine production is 180,000 tons (163,293 tonnes) per day with a stripping ratio of 2:1. During the startup phase of the mine, the required fragmentation size was easy to achieve as the ore was highly weathered and fractured near the surface. As the mine depth increased, the proper fragmentation size became harder to achieve due to less weathering and different rock types. Because copper recovery increases as crusher product size decreases, achieving the appropriate product size at the crusher is the operating priority.

Jan 1, 2010

By D. Brandt

The Dos Pobres Mine is a copper oxide heap-leach mine located near Safford, Arizona. Mine production is 180,000 tons (163,293 tonnes) per day with a stripping ratio of 2:1. During the startup phase of the mine, the required fragmentation size was easy to achieve as the ore was highly weathered and fractured near the surface. As the mine depth increased, the proper fragmentation size became harder to achieve due to less weathering and different rock types. Because copper recovery increases as crusher product size decreases, achieving the appropriate product size at the crusher is the operating priority. The Engineering Department started a project to improve fragmentation through blasting and thus increase throughput in the crushing system. It soon became clear that input from other departments was going to be required to make this a safe and economical project. Therefore the Crush and Convey and Ore Control departments worked together to evaluate all available data on blast patterns and explosive loads and tracked performance and results. Using image analysis, Drill Energy Index and databases, we have been able to improve fragmentation size and verify the results while controlling costs.

Jan 1, 2011

By George A. Miller

AMERICANS like engines, but more than anything they like powerful engines, and next to that they want them quiet, silent, smooth; perhaps a slight purr might be permitted, but they must not knock. To provide a gasoline to fit all these requirements, American petroleum technologists have experimented for years, and mounting octane numbers of the gasolines the refiners have produced both before and during the war bear witness to their success. The question on everyone's mind now is what may we expect in the way of engine fuel in the postwar period? The gasoline drouth during the war rationing, the inconvenience of doing without a car were major annoyances to all motorists, but they put up with them pretty cheerfully for the most part. However, now that the war is over, and the jalopies are all out and the better cars have been taken off the jacks and brought out on the road, the call is for "Some of that good gas-fill her up, if you please."

Jan 1, 1945

By L M. Zhang, X Y. Li

Surface displacements are routinely monitored at multiple points during slope excavation. The monitoring data reveals the safety status of the slope under current loading conditions. They can be used to enhance the prediction of the future performance of the slope by reducing the uncertainties of the prediction model and its model parameters. In a multistage excavation, the observed displacements in the current stage can be used to update the prediction of the displacements in subsequent stages. Besides, due to the spatial correlation of the slope parameters, the prediction of the displacement at one location can also be updated using the monitored displacements at adjacent locations. This study aims to develop a multistep updating method to enhance the prediction of the future performance of the slope using time-series monitoring data at multiple points. This method integrates the theoretical computational model with observational evidence. It considers the inherent uncertainty of the slope, model uncertainty and measurement uncertainty. With more monitoring information being incorporated, the prediction becomes closer to the actual performance of the slope. A case study of a multistage excavation of an extremely high rock slope in south-west China is presented for illustration.CITATION:Li, X Y and Zhang, L M, 2014. Better prediction of performance of a slope using time-series monitoring data at multiple points in a multistep excavation, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 183–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By R. J. Caine

Like most major firms engaged in project management, Dravo Corporation faces a constant challenge to keep its management systems in tune with the ever-increasing demands imposed by larger and more complex projects. This paper suggests that one of the key elements in meeting this challenge is more effective organization of project data. It reveals some of the details of a program at Dravo's Minerals 6 Metals Division which seeks, through better organization of project data, to improve Dravo's capabilities in estimating, cost control, scheduling, performance reporting and material control. In particular, this paper discusses ideas Dravo is developing for improved job numbering, codes of accounts, requisition and purchase order numbering, inventory cataloging, and employee/badge numbering.

Jan 1, 1980

By Ralph H. Sweetser

MUCH progress in -blast-furnace construction and in the manufacture of firebrick for furnace linings has been made since the publication of Bulletin 130 of the U. S. Bureau of Mines on "Blast-Furnace Breakouts, Explosions and Slips, and Methods of Prevention," by F. H. Willcox in 1917. At the time of publishing this report comparatively little information was available to blast-furnace men as to the fundamental facts relating to the character of blast-furnace refractories. Some of the accepted theories of only a few years ago have been completely reversed. The mortality of blast-furnace linings used to be so great that nearly every furnace plant had one or more complete linings in the brick shed ready for use in case of a lining suddenly "going out"; it was generally accepted that a furnace could not "keep her lines" more than two or three years at best, and often a hot spot in the shell would develop, or a breakout occur in the hearth or bosh within a year or two after blowing in on a new lining. In some respects these frequent relinings were not so detrimental as to he a complete loss because they afforded opportunities to take advantage of advances in blast-furnace practice. At present the cost of relining has greatly increased, but the life of a lining has also increased. Anything less than five years on a lining is now considered a short blast.

Jan 1, 1932