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R. B. BRinsmade, Ixmiquilpan, Hgo., Mexico (written discussion").—how far ahead of the United States are the self-governing British colonies in their application of economic democracy is well illustrated by Mr. Godson's paper. To prove this, I need quote only two of his assertions, the italics being mine: "lt is a stern fundamental principle that a11 natural resources are the inalienable property of the crown.'' "The right to a claim should only exist as long as it is worked or taxed to insure work. Once depart from that sound maxim, there results improper control of the natural resources of the country, which primarily belong to the people." These assertions formed the basis of my criticism1 of Dr. Raymond's paper in 1913, and they should be inscribed in letters of gold above the entrance to the office of every county recorder in the United States. I venture to assert that the existing United States mineral land laws are essentially unfair to the nation and a hindrance to the legitimate miner, because they fail to embody the above quoted principlca; and this applies both to state laws east of the Mississippi and to federal laws in the West. That these laws favor the forestaller and the monopolist, defraud the government of its fair share of the profits of mineral production, and tend to industrial feudalism must be evident to any competent unbiassed observer. The fact that no serious political movement arose to change them, until the conservation agitation of the last decade, may be largely explained by two salient conditions. First, as stated by President Winchell, "for a long time there was such a vast surplus, or excessive amount of unwanted, undesirable land in the West that the land offices did not scrutinize the claim sought to be located;" second, that the millions of individual farm owners throughout the country could easily be aroused, by the special pleaders hired by the great land speculators and monopolists, to use their vast political power for the suppression of any statesmen striving to incorporate in our semi-feudal land laws any such principles as those quoted from Mr. Godson. While agreeing with Mr. Godson that a freehold or fee-simple title, if coupled with obligatory continuous work, may have the same practical effect as a lease, it seems to be the experience of the most active and

Jan 1, 1920

S.L. Barua and Y.C. Kim M. Armstrong's paper is very interesting and can be regarded as a pioneering work of applying geostatistics on washed coal. The density levels used in her study are uniformly spaced, which facilitated curve fitting through a proper experimental design. Most of the existing coal washing plants in the US, however, gather washability data at non-uniform intervals which, in turn, affects the goodness of curve fitting. We would like to emphasize the importance of having a proper experimental design, if a similar geostatistical application is to be conducted on washed coal. We, at the University of Arizona, tried the variogram on recovery (Kim, Barua, and Baafi, 1982, SME preprint 82-143) which showed a similar pattern as Fig. 4 of Armstrong's paper. In both cases, the first experimental variogram value is invariably and inexplicably higher than the second variogram value. Although Armstrong ignores the first point because of "small number of sample points," we did not do so because there were 17 sample pairs. As a consequence, we concluded that the obtained experimental variogram was unsatisfactory and that further research is warranted. In other words, this disagreement in variogram interpretation between M. Armstrong and the University of Arizona begs the question whether the experimental variogram of Fig. 4 truly reflects the spatial correlation in washed coal, assuming there is such a correlation. Finally, we wish that Armstrong could have done a similar study on clean sulfur, which is a vital interest to the coal mines in the US. Her implied remark on sulfur in the concluding section of the paper may turn out to be incorrect because our experimental variograms on clean sulfur at different density levels were even less satisfactory than those on recovery.

Jan 1, 1985

Jan 1, 1985

By A. D. Hughes

C. W. MERRILL*-Mr. Hughes' paper not only is very well presented but is most timely in that it covers a subject of vital interest to the United States. Tin is one of the strategic metals which has not been found here in appreciable quantities. The total United States tin output since the first recorded production over 100 years ago would not supply current consumption for a fortnight. On the consumption side, tin is extremely important in national defense because of its use in tin plate which, in the form of tin cans, makes it possible to feed properly the armies that the United States recruits from its civilian population in emergencies. Moreover, the internal combustion engines so important in powering tanks, planes, and other war machines, require large quantities of tin alloys for bearings and for soldering. These considerations, along with the fact that Malaya, historically, has been the leading source of tin to the United States, make the kind of information that Mr. Hughes has presented so ably, a matter of vital interest.

Jan 1, 1949

We would like to thank Mr. Mandolesi for his informative paper on rails from strand cast steel. The chemical and structural properties of the strand cast steel were of particular interest to us. We would like to supplement his excellent report with some of Inland's findings from our Caster with submerged nozzles and strands reduced in line from 7" x 7" to 5-5/8" square cross section. Inland has conducted extensive segregation studies on AISI 1049 steel - Fine Grain 0.50% carbon and 0.75% manganese. Based on approximately 80 heats, our normal segregation pattern results in analyses of .49% carbon in the center, and 0.50% carbon at the midway and edge position. The sulfur analysis averages .025% in the center, .027% midway, and .026% at the edge. Note the slight negative segregation between the center and midway position. This steel, being lower carbon and probably cast nearer the liquidus, resulted in less segregation than the 0.80% carbon rail steel.

Jan 1, 1972

MR. STOUT: The picture shows the plan of the "V"-system as worked at Berwind mine, in a small strip of coal adjacent to the 4th right entry. The dotted line (indicating) show the position of the break rows as set for each of the three consecutive breaks. In two cases the break rows failed to function properly and as a result, the roof caved along the points of the "V's" as well as back along the faces a short distance. This affected the ventilation to a certain extent, but was remedied immediately by cutting through the points near the cave and setting additional timbers. At the present time we are putting in the break row of heavy red spruce props, making the row straight instead of curved as is shown in the picture; in this way we believe we can better control the breaks. The three "V" entries were driven up 14 feet wide, for a distance of 260 feet without cross-cuts. A very neat and substantial line brattice was carried up each entry as the places advanced. The principal factors in determining the success of this system are ventilation, roof control, and transportation. We are well pleased with the results from these three "V" places and now have four other places, about 500 feet to the west of these, driving at the present time in which we hope to get still better results. A MEMBER: What centers did you use there? MR. STOUT: We used 70 feet. This may be increased or decreased according to local conditions. MR. F. W. WHITESIDE (Chief Engineer, Victor-American Fuel Co.) Will you please describe roughly how your cars are handled? MR. STOUT: Cars are brought from the parting and pushed up along the faces by a storage battery locomotive. The faces are about 70 feet long and we found that five or six cars can be loaded and transported very conveniently. It is important to get a quick exchange of cars, and in this way we were able to keep the shovelers busy at all times. A MEMBER: What is the grade in your "V" entries? MR. STOUT: Five per cent in favor of the loaded trip. A MEMBER: What is the angle of your "V" faces? MR. STOUT: The angle at the throat is 45 degrees. MR. SAMUEL ANDREWS: In what direction does the air travel? MR. STOUT: The air travels down the dip entries and is deflected up the first "V" entry, and travels along the points, and returns down the last entry. There is no more difficulty in ventilating "V" faces than in ventilating rooms, providing the points are kept open. A MEMBER: What amount of air do you have in that section? MR. KAISER (Superintendent, Berwind Mine): Eighteen thousand cubic feet per minute. MR. ANDREWS: It is necessary, Mr. Stout, to brattice these places?

Jan 1, 1925

By Peter Stubbs

Mr. Agelopas is to be congratulated on a fine paper. Although the presentation was simple and concise, you will all appreciate that a great deal of hard work went into the development of this highly successful repair method. Earlier this year Bethlehem invited a group of our people to witness lug repairs at their Sparrow's Point plant. We have since made lug replacements on a trial basis using their method. The repaired moulds are now back in service. We will compare their performance with regular moulds and with moulds repaired by a technique developed by Dofasco weld shop personnel. I would like to explain briefly some of the various types of ingot mould repairs presently undertaken at Dofasco. The first problem will be familiar to most of you. The lower inside edge of a mould wall may be damaged by spalling, a runout or by the washing action of steel deflected from a badly worn stool cavity. We repair this type of damage by welding.

Jan 1, 1972

BENEDICT SHUBART: I am rather surprised at one statement of Mr. McKeehan, that he found it satisfactory to bond only one track. It has always been my idea of good practice to bond both tracks and cross bond frequently, so that in case of any break in the bonding of one track, which frequently occurs, there will be no interruption in the circuit.

Jan 1, 1923

By Brandon Buschmeier, Frederic Masse

"Inclusions are a type of ground improvement that provide an improvement of a soil mass by insertion of a material with better characteristics than the surrounding soils. There are primarily two types of inclusions: “Soft” inclusions which are constructed of granular material (Stone Columns, Rammed Aggregate Piers, VibroPiers...), and “rigid” inclusions which are constructed of grout inserted with or without pressure (VibroConcrete Columns, Controlled Modulus Columns, Soil Mixing Columns).While the central principle of the inclusions is similar (i.e., overall improvement of characteristics of the soil mass below the structure), the load transfer mechanism is radically different for each technique. Therefore, the applicable design methodology is specific to the type of inclusions and there exists no universal method of design which spans across all inclusions.This paper will present an in-depth comparison between the standard design methods used for “soft” granular-type inclusions (Priebe modified, Balaam & Booker, Goughnour & Bayuk...) and the methods used for “rigid” inclusions which mainly rely on finite element analysis. The paper will explain why the design for soft inclusion methods cannot be applied to rigid inclusions and vice-versa. Each design method will be reviewed in detail to better emphasize its limitations and advantages.Two case histories will also be presented; one for each type of inclusions in order to illustrate the concepts developed in the first part of the paper.1 INTRODUCTION1.1 GENERAL OVERVIEW OF GROUND IMPROVEMENT WITH INCLUSIONSThe use of ground improvement methods to provide the appropriate amount of foundation support is a growing and constantly evolving industry. Traditional structural foundation methods including ‘shallow’ and ‘deep’ foundations do not adequately address the wide range of settlement tolerances, soil conditions, and loading considerations inherent to each unique potential project. In some instances, ‘shallow’ foundation solutions are simply not feasible due to soil and loading constraints. Furthermore, ‘deep’ foundation solutions are used to ‘bridge’ the soft compressible soils, ensuring that the entirety of the load in the structure is transmitted through individual elements into competent layers below the ground surface (bedrock, dense residual soils). Highly concentrated structural loads are transferred into the individual elements by means of direct contact requiring the use of structurally rigid surficial components (structural slabs, grade beams, and pile caps).Ground improvement bridges the gap between these two traditional methods, offering adequate foundation support while using more costeffective techniques and design methodologies. Inclusions are a type of ground improvement used to provide a reinforcement of the soil mass through the vertical insertion of a material with better characteristics than the surrounding soils. Much like deep foundations, inclusions are installed through soil layers with high compressibility and/or low bearing capacity and terminated in a suitable bearing stratum. However, unlike deep foundations, ground improvement inclusions rely on a distribution of load between the soil and the inclusions. By doing so, some of the structural load is applied directly to the soil in a proportion equal to its bearing capacity and compressibility limits, while the rest of the load is shed into the vertical inclusions down to the bearing stratum. Load sharing is a critical aspect in the performance and design of the various ground improvement methods."

Jan 1, 2015

It was said that the coal operators are losing a great advantage in permitting the oil producers to take the domestic market away from them. Coal is so much less expensive and more economical than oil that even the oil producers themselves are burning coal under their stills. No longer is the housewife afraid of machinery. Not only does she operate an automobile, but in her home she is used to vacuum sweepers, washing machines, refrigerators, and multitudinous devices. She is no longer machine-shy. An electrically operated stoker, if properly introduced and guaranteed with only a fraction of the enthusiasm that the oil furnace salesman shows, would get a ready reception. Several devices now on the market are much less complicated, much less apt to get out of order, than the oil burners. In place of an increased cost for the sake of convenience, the stoker will give all this convenience at a decreased cost. So said Mr. Herres. He said, however, that it must be enclosed so that the working parts are not too much in evidence. MR. McAULIFFE: While it appears possible to adapt a continuous feed to the needs of the furnace in an apartment or a house burning thirty tons or more annually, it is not yet possible to get a furnace that would satisfy the home which burns only seven or eight tons in a season. A delegate described the Garrison stoker which is designed to care for this problem. Mr. Herres said that the Pacific Coal Company had a small stoker furnace more simple than the Harrington. Pulverized coal equipment is being adapted to use in apartment houses. The stoker designed by Lloyd Garrison, State Engineer of Utah, was described, and also one which Mr. G. W. Megeath of Omaha, Nebraska, had manufactured, which Mr. McAuliffe says, is recommended only for Rock Springs coal. It was brought out that there are over forty installations of the "Iran Fireman" in Salt Lake City. For apartment buildings, there is no question as to their satisfaction. Many of the down town office buildings are so heated.

Jan 1, 1925

Remarks Of Mr. Robert W. Hunt, General Superintendent, Albany And Rensselaer Iron And Steel Company., Troy N. Y. - In discussing Dr. Dudley's two most interesting papers, I feel a natural hesitancy in disagreeing with conclusions formed after such careful and conscientious work. But I think he has made his deductions from too meagre premises. The analyses of but twenty-five samples are entirely too few to justify the establishment of so important a formula. When we consider that he indirectly proposes to regulate an interest amounting, even at the present low prices, to over $20,000,000 per annum, we may well hesitate before accepting a formula based upon the chemical and physical analyses of but twenty-five steel rails. Dr. Dudley touches the keynote in referring to the proposed labors of the Government Test Commission. They based their hopes of attaining success upon the chemical and physical analyses of a very large number of samples, and in the only branch of investigation which the short-sighted policy of Congress has allowed them to complete, i.e., chain cables, we find that a dozen, twenty-five or one hundred tests gave no satisfactory results. It was only after many hundreds that they were enabled to draw conclusions. There are so many circumstances bearing upon the life of a rail, that the task of extracting a correct result seems herculean. I presume I am right in stating that in our Northern latitudes early winter and spring months witness the breaking of the greatest number of rails, thus seeming to prove that an unstable road-bed has much to answer for. Then, again, broken and flattened wheels must be taken into account, but I am convinced that more rails have been broken by the treatment which they received before leaving the rolling-mill * The remarks of the participants in this debate have been written out by the speakers, and are here given without any attempt to retain the order of the dis¬cussion. While the report does not, therefore, preserve the vigor and spontaneity of the debate, it is believed that it gains in value by giving the matured views of the speakers. The continuation of this discussion at the Pittsburgh Meeting, May, 1879 (beginning with remarks of Mr. Cloud on page 401), is appended for convenience of reference.-T. M. D., Sec'y

Jan 1, 1879

William P. Blake, TUCSON, Ariz. (communication to the Secretary): As one who in youth, now nearly half a century ago, had the privilege of participating in the initial explorations which have alreacly resulted, within a single lifetime, in the establishment and Development of a vast continental empire, so well described by Dr. Douglas, I may be permitted to supplement with some additional details the comprehensive sketch given in his paper. Before the War Department, in 1853, sent out the Pacific railroad exploring parties, Fremont had already made his memorable expeditions, exploring the Great Basin and the passes into California; Sitgreaves had traversed, from east to west, the Zuni and Moqui country; and, still later, Emory had examined the region along the boundary-line between the United States and Mexico. The services of these pioneers deserve to be mentioned in even an outline of the history of continental development. Concerning the five practicable railroad-routes, suggested in the Reports of Explorations aid Surveys," etc., as published

Jan 1, 1900

Edward Keller, Baltimore, Md. (communication to the Secretary): When, at the New Pork meeting, February, 1899, Mr. Douglas gave an abstract of his highly interesting paper on the Copper Queen mine, he invited the members of the Institute, in his usual progressive spirit, to make a full scientific investigation of the region of that mine during the prospective excursion to Bisbee, Arizona. I volunteered to examine some of the metallurgical processes and products of the works, and obtained from Mr. Douglas a valuable series of samples. Upon the issue of his paper, however, I found that he had already a considerable volume of analyses of those products, and that little was left for me to do in that respect, except to duplicate his results, the importance of which work would not have been commensurate to the time and labor involved. I selected, therefore, only some points which he had not made entirely clear, or concerning which I was skeptical. The details of most of my work will appear in a future paper. From Mr. Douglas's figures I have calculated the values for the elimination of impurities in the so-called Leghorn converter, introduced by him at the Copper Queen works, and have found them to be as follows: Percentage of Elimination of Impurities in Pour Blows of a Converter. No of ' Selenium Sulph'r Iron. Zinc. I Nickel. Lead. Antimony Arsenic. and Blow- ! Tellurium .. 1.......... 99.4 99.6 88.0 92.6 94.4 81.6 83.8 40.3 2.......... 99.0 99.6 98.1 92.5 96.8 71.9 76.6 38.1 3.......... 98.8 99.5 93.5 91.4 96.3 63.8 80.6 25.3 4.......... 99.8 99.5 95.8 95.8 97.5 65.3 76.9 36.3 Average 99.2 99.6 93.8 93.1 . 96.2 70.6 ! 79.5 35.0

Jan 1, 1900

By Hickling G.

Discussion at the Manchester Geological and Mining Society's general meeting held in Manchester, February 8th 1916, with Mr. Leonard R. Fletcher, President, in the chair, of papers previously published in Trans. Inst. Min. Engrs.,1915, vol. L, p.322 and p.328. Included are a written contribution by Ollerenshaw W. and oral discussion by the author, Gerrard J., Paton J.D., Smith S.A., Stephenson H., Dixon H.O., Pickup W., Fletcher L.R. and Atherton H.S.

Dec 1, 1916

CONCLUSIONS: Our experience, where we attempt to remove a continuous face with a seam more than six and one-half feet in thickness, has been rather disastrous. We have been able to open up faces and retreat for a distance of 75 to 100 feet in this particular character of coal, but after the supporting timbers have been removed for the second or third time we have found that the roof has a tendency to ride over the props and break off at the face of the coal support. However, where our coal is below six and one-half feet in thickness we have had very good success in handling the roof and breaking it off systematically with our break line of props, which are usually from 12 to 15 feet from the face of the coal. Our practice in to set props at about two-foot intervals in each direction and remove two sets of props, at the same time two additional sets are placed along the coal face. At all times we are very insistent that all props be removed from the gob and that entire coal be taken out so that it is possible for the roof to break freely and all come down, not having any supporting pillars in the gob. The conclusion of our experiments to date is that if all the supports beyond the breaking line of props are taken out as the long face retreats and the closer the breaking line of props is kept to the face the better the results will be. We have never felt it safe to have less than four rows of props to protect the machinery and men working along the coal face. We feel that the time element as to the rapidity with which these faces are advanced or retreated, is of vast importance, but to date have not had an opportunity or experience enough to reach any conclusion as to what time element is proper here with us. We feel that the crushing strength of the overlying strata will govern this to a large extent, and as ours varies considerably, it is going to he very difficult for us to reach a definite conclusion. My opinion is, that conditions may be such that rather than have a short face and retreat rapidly, it will be found that a longer facewith a slower retreat will work out better. Such a condition might give the overlying strata time to settle. The caving of roof or of control of this caving, with us, is quite closely associated with the ventilation. We find that the places where the strata overlying the coal are composed of shale, that the effect of the air on this is of very great importance. It is our endeavor, at all times, not only to remove obnoxious gases, but to keep a current of fresh air moving along the face and, of course, a portion of this travels over the gob and comes in contact with the roof and overlying strata. This, we find, helps materially in keeping the roof on the move. As it is our practice to keep water for sprinkling purposes at all places, we also use this water to keep the roof wet back in the gob. The effect of water on the shale is to cause it to disintegrate quite rapidly. MR. HOLMAN (Concluding): If there are any questions about this, I will be glad to answer them. I have some prints and also some pictures of the scraper loader and the shaking conveyors (distributes.) PRESIDENT MOSES: We wish to thank you, Mr. Holman, and also wish that you would thank Mr. Dupont for his paper. Are there any discussions? Do you wish to ask Mr. Holman any questions? (No response.) PRESIDENT MOSES: Mr. Holman, I would like to ask you how you take the photographs; were they taken by flashlight, or were globes used, or how were they taken, in a gaseous mine? MR. HOLMAN: Our mines being gaseous, we do not use the ordinary flashlight for taking underground photographs, but we have had considerable success, I think, with underground pictures by means of electric lights. We use 250 watt globes. We have six of these rigged up with tin reflectors, 18 inches in diameter, on standards, and we carry two or three hundred feet of wire connected with these six lights, and they can be turned on in the room where we take the photograph, by means of this extra wire. We set the kodak up and arrange the picture and take a long time-exposure. We usually take an

Jan 1, 1926

MR. SHUBART: Mr. Miller's paper mentioned the two processes that seemed to be a success, the Smith process and the Piron process. I suppose the main difference is this, that Smith's process is to furnish domestic fuel and the by-products while the Piron process that Ford is installing is for fuel for power plants. I would like to ask Mr. Miller something about the commercial cost of the process. With the briquette you must make it cheap enough to sell. What are the commercial possibilities of Smith's briquette? MR. MILLER: It is pretty hard to say what the cost would be at this time, owing to the fact that slack has advanced double, or even more at the time I was in New York with the plant, but at that time it was costing $1.10 for the operation. You can add to that, of course, the cost of the coke. One dollar and ten cents was the entire cost of plant operation. It takes about one and one-half tons of coal to make a ton of briquettes. One dollar and ten cents takes care of all the material, cost, labor, handling, etc. Labor was much cheaper then. I would say it would cost about $2.20 now. The cost of coal is what you can buy it for on the market. I don't think, however, that the carbocoal process will ever meet with any great favor for the simple reason that it is really a prepared fancy fuel. It is going to be nice for people in offices where they want a grate or for families where they want a nice clean fuel. It leaves no stain on the fingers, no odor to it. It seems in carbonizing coal we change the carbon molecule. For instance, we are all familiar with the diamond. It is carbon, yet it requires a tremendous heat to burn a common little diamond. But you can set a piece of charcoal afire, which is also carbon, with a match. The molecular form has been changed in carbonizing coal, i. e., it is larger. Carbocoal will fire very readily, it can be started with a piece' of paper. I think the Piron process will be the process, i. e., to simply take out the tars and light oils, then fire direct-have the distillate plants right on the job. CHAIR: Can Mr. Shubart tell us something of the mechanical part of the Piron process? MR. SHUBART: The Piron process is of interest because Mr. Ford is taking it up. He has made so few mechanical mistakes it makes us feel that it is a success. Piron is a chemist of high accomplishment and reputation. The thing about the proces is its simplicity. Mr. Smith's is a very elaborate process, but Piron has gotten around all that. Piron feeds the raw coal in at about one-half inch mesh or smaller. He feeds it into a retort about 55 feet long, 16 feet wide over all. He has a hearth about 6 feet wide and the length of the retort. The base of the hearth that carries the coal is a conveyor, a flat cast iron conveyor, a very massive affair, very accurately made, so that there is no loss of coal. Between the upper and lower strands of the ' conveyor is a bath of molten lead which gives an accurate control of temperature. For best results he must have temperature of not under 800 F., not over 1,300 degrees F., about 1,100 or 1,200 F. seems to be ideal for getting greatest yield of oils and the best tars and other by-products. This lead bath has a system of flues running through it that

Jan 1, 1923

Mr. Shepard's paper was unfortunately delivered extemperaneously so no record is at hand. He spoke most interestingly and at length on the oil shales of Colorado, giving his opinion as to the ultimate outcome of the oil shale industry. He explained his idea that it would be built up of comparatively small plants, each of which would make the crudes, or more exactly would roughly divide the crude into its fractions, piping or shipping the fractions to a Central Refinery, using the residue for fertilizer, as it runs very high in fertilizer salts. He recommended that this plan be taken up by Coal Producers, that they consider the possibility of breaking up coal and selling its more refined products in place of selling raw coal. He spoke at length of the various outlets for products of distillation. Mr. McDermott gave a very interesting talk later on work that is being done in the Northern Colorado field along these lines. Mr. McDermott mentioned the strange fact that coaly materials such as mother of coal appeared to give just as good or better results under distillation than did lignite coal. Messrs. Randall, Howe, Goddard, Danford, and Nash added interesting data covering the use of pulverized fuel, and this data will be collected and offered to the Institute later in the form of a paper. Mr. Young spoke of the use of powdered coal in small units for small plants, mentioning the system now being offered by an Eastern Iron Works for small heating plants.

Jan 1, 1922

A great many questions were asked Mr. Bright, and Mr. Bright's opinion was given on a number of subjects. He spoke at length on spring suspension of locomotives, bringing out the necessity for better spring suspension due to heavier weights and higher speeds now developed. The subject of dynamic braking was brought up, and the opinion of the engineers present was that dynamic braking was not a desirable feature except where heavy, long, adverse grade is encountered. Mr. Goddard and Mr. Bright had a spirited discussion regarding ball bearings, bringing out the opinion of the meeting that ball bearings in motors are preferable to sleeve bearings, and the few failures so far encountered are due to improper application or insufficient size of bearing. Mr. Shubart brought up the question of locomotive speed, mentioning some high speed work on main haulage, also an interesting experiment in a large Eastern mine where very slow speed, 3 1/2 miles per hour, gathering locomotives were substituted for the high speed gathering locomotives with an increase in cars gathered and a material decrease in derailment and accident. Mr. Bright mentioned the improvement in gathering reels, and Mr. Shubart mentioned the safety in the use of the concentric cable in direct current, using the outer wire as the ground wire, so that in case of accident to the cable, the ground wire acted as a protector to the live wire, materially decreasing the danger of sparking. Mr. H. I. Smith of the Bureau of Mines brought up the question of explosion proof construction, and Mr.. Bright and. Mr. Shubart explained the construction adopted by two of the larger manufacturers. Experiment has shown that the force of explosion in motors due to gas does not exceed 150 pounds per square inch. All forms of screen or baffles have proven an actual source of danger, due to the collection of dust, usually soaked in oil, forming an active means of propagating flame, together with the fact that all these appendages are frequently left off when the motors are repaired. Modern construction eliminates all openings, screens, devices for stopping or extinguishing flame. The motor is made entirely enclosed, practically air tight, all joints are ground and all openings necessary for access and attention are closed by bolted plates. The case is made stout enough to withstand any interior explosions, and ample ribbing is provided for heat dissipation. Mr. Bright was asked regarding the use of contactor control. He replied that his company is now recommending contactor controls for series and parallel starting on all locomotives of 13 tons and over, and particularly on the tandem units that are now becoming popular in coal mining work. The question of dynamic braking and reversing was brought up and Mr. Bright explained that this made a very complicated contactor installation but they had

Jan 1, 1922

(Referring to map) If there are any methods to improve on this I would like to have some suggestions on it. The maps there are on a scale of one inch to two hundred feet. At the time of each extension a letter is used and a line drawn across the entry and the room. The date of the extension is given up in the margin of the map. Here is an extension made April 6th. Extension L is shown in each one of the rooms, November 29th. N-you see the two rooms have been finished down into here. 0-the last extension, has just been stopped, and the three working rooms. Now, one of the features of this plan, when the rooms have been stopped, the line is drawn straight across. When the room or entry is still going, there is a small projection beyond the line, indicating that the next cut is changed. When the distance cannot be ascertained by the engineer, he gets the distance from the mine boss or some other source which is reliable, and that is put on in a dotted line. That gives you a complete story. Anyone looking over the map can see immediately every place that was working at the time of this extension, every place that is inaccessible, and get a complete picture. The extension of the coal is put on the extension at each extension. The survey stations are put in, showing each survey point. The pillars when they are pulled-only the pillars that are pulled are cross-hatched. The whole map is in cross-hatch without any regard as to what pillars are pulled. If a little stump is left in, that is shown on the map. The engineer only shows what pillars are pulled that he has actual knowledge of, or has been given to him in detail by the mine foreman. I believe that concludes the work on the mine map, and there is certainly room for a lot of improvement on most of the mine maps which we have been getting into the office. PRESIDENT PRYDE: Does anyone want to ask any questions? Any questions about the leasing regulations? I want to say there are several leases in the Rock Springs field, and when Mr. Smith comes on one of his visits the Rock Springs Institute have asked him to address them on the leasing proposition.

Jan 1, 1924

D. HARRINGTON: Owing to lack of funds, the United States Bureau of Mines have made no experiments in the Bruceton mines in the use of mudite. MR. McAULIFFE: I doubt that mudite cam be delivered at fifty cents a ton and that a mile of heading can be treated with mudite for ten dollars. You could not dig a ton of sand out of a sand hank for that money. L. C. CLARE: The tram road leading to Wattis mine crosses a shale bed and it is easy to screen the shale through a %-inch sieve and load it into a mine car. W. J. REID: A slow trip passing through a mudited entry will dislodge practically no dust, a rapid trip will make air disturbance enough to coat the cars with fine dust. MR. PRYDE: We have used mudite on stoppings around a fire in Reliance and for two months thought they were getting good results, but the fire was found to be drawing air and to be spreading. This mudite was smeared over the stoppings with a trowel. After this apparently failed we used dry adobe.

Jan 1, 1925