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By J. J. Wilson

To explain in detail the manufacture of seamless pipe and tubes is something I venture to say that has never been done to a point entirely satisfactory. The manufacture of seamless tubes dates back to 1885, when Mannesmann Brothers invented the roll-piercing mill. Ten years later R. C. Stiefel invented the disc-piercer, which first came into general use in this country. At the present time the Mannesmann roll and the Stiefel disc-piercers are used, the Mannesmann rolls particularly for the larger size billets. Sizes produced at first were relatively small and the product was cold drawn to provide a smooth surface. The early uses of seamless material were chiefly for mechanical purposes, such as boiler tubes and bicycle tubing, and the latter for some years taking the heaviest tonnage. Improvements in the hot process were gradually made; the early Pilger type rolls were largely superseded by the two-high rolling mill for rolling out the tube after being pierced, the reeling machine for diagonal rolling, the sizing mill for giving exact outside diameter, and finally the sinking mill for reducing larger diameter tubes to smaller diameters.

Jan 1, 1932

Past President Shirl McArthur opened the meeting at 9:30 a.m. He called on the Auditing Committee to give its report. Stan Shubart, who checked the financia1 report of the treasurer, read the report. He asked that it be approved. A motion was made, seconded and carried. Shirl thanked all the committees for an excellent job in making this meeting a most successful one. Special thanks to Park Lamborn for a fine program and to Gussie Whiteside for all her efforts in behalf of the Institute. An increase in salary was voted for the secretary-treasurer. It was decided to return to Vail for the 1979 convention. The Resolutions Committee was called upon to give its report. Roy Coulson, Chairman, submitted the following: (I) RESOLVED, Whereas, in the year since the last convention of The Rocky Mountain Coal Mining Institute, the Institute and the coal mining industry have suffered the loss through death of the services of: O. F. Bridwell C. L. Book O. F. Lewis Frank Kolar O. H. Littrell L. B. Phillippi Weston L. Potter George C. Trevorrow

Jan 1, 1978

CHAIRMAN ALLEN: Gentlemen, I have been asked to call this meeting to order by Mr. Marchant, and am acting here temporarily in the absence of Mr. Nyman, who is unable to be with us. Mr. Nyman sends the following telegram: "Will not be able to be present at the Institute meeting. Serious illness of my father has made it necessary for me to remain in Salt Lake Please arrange substitute. Very sorry." In addition to having to pinch-hit for Mr. Marchant and President Nyman, I am here representing the Governor of the State of Colorado also who is unable to be here. The Governor of Colorado is a very busy man. His appointments are made months ahead. We only got word of the possibility of his addressing this meeting yesterday morning, and I went over to the Governor's office this morning to see if there was any possibility of getting him here, but he had been booked up for two months ahead of this time to appear at the convention of the Veterans of Foreign Wars in Trinidad, Colorado, where he is today, and which makes it impossible for him to attend this meeting. I know that he would have liked to have been here with you, as there is not any doubt but what the Governor of Colorado has the interests of the mining industry at heart. This was manifested last week when he called a meeting of representative men of the different lines of industry so that we could arrive at some results and some arrangements to see if it was possible to get at the bottom of the condition causing our bad times, and the appointment of commit- tee groups to find out what these problems were and to see if they could get any possible solution to them. The meeting was adjourned with the suggestion that those who were present would among themselves select such committees to investigate the conditions of the coal mining industry, and offer suggestions for betterment.

Jan 1, 1938

By Harold J. Rose

It is a real pleasure to attend another meeting of the Institute. This is partly because I am a Westerner by birth and training. As a young man I had personal experience with firing Colorado and Wyoming coals. The coal industry of the United States has done an outstanding job of producing coal. We can all be proud of the industry's record of continuously adopting technical improvements in coal mining. NEED FOR MORE EFFECTIVE COAL MARKETING However, it cannot be said that the industry has done an equally good job of marketing coal. There has been a rapid growth in U. S. population, and an even greater expansion of industrial demands for heat and power. Yet coal consumption for the past several years has been no greater than it was 40 years ago, in 1912 and 1913.

Jan 1, 1954

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

The meeting was called to order with President George B. Pryde in the chair, and C. M. Schloss, acting Secrcetary. The meeting immediately pro¬ceeded to the reading of the papers. Mr. L. S. Ickis read a paper by A. L. Jones, entitled, "Underground Sub-Station Control," and elaborating on the general topic of automatic sub-stations. The discussion was led in part by Mr. E. H. Weitzel, acting as Chairman, in Mr. Pryde's temporary absence. Mr. S. R. DeBoer, who specializes on landscape architecture, gave an interesting talk on the subject of "City Planning and Landscape Architecture for Western Coal Camps." Notes were taken of this talk, which will be found in the proceedings. Mr. Pryde then resumed the Chair; There was no discussion of this paper. Mr. Thomas Foster, of Reliance, Wyoming, then read his paper on "Coal Dust in Mines." After the discussion of Mr. Foster's paper, the discussion of Mr. McKeehan's paper on track bonding, read at the Salt Lake meeting, was resumed, and this discussion will be found printed separately in the proceedings. Mr. Schloss then read an amusing and friendly telegram from C. H. Stevenson, of Price, Utah, which caused considerable merriment, and the Chairman asked Messrs. Weitzel, Littlejohn and Schloss to form an appro¬priate answer, and they answered it in the same spirit. The Chairman then announced the banquet for Wednesday evening and the Theatre Party for Thursday evening. The meeting then adjourned. The meeting resumed at 10:15 A. M., Thursday, February 14, 1924. The Chairman announced a photograph of the meeting to be taken at noon, on the Post Office steps, after which the Chairman appointed a nom¬inating committee, consisting of George A. Murphy, F. W. Whiteside and

Jan 1, 1924

By Gilbert Davis

MR. DAVIS: When the Secretary asked me to continue our accident experience in safety work at Dawson to cover the year just closed, I rather felt that he was asking 'a good deal, for we had said about everything that we could last year. I am not going to say very much, but in line with his request I have merely brought the figures up to date. I want to say, to start, that 1934 was, rather disappointing. It was the poorest year since 1930, as you will notice (indicates on diagram). This first column represents the accidents per thousand shifts worked. We cannot assign any real valid reason for the increase. We think we worked just as hard, but we are rather inclined to lay it onto the times; in other words, to lay it to the unrest and the changing conditions that are existent not only in this country but probably all over the world. We had twelve lost time accidents last year. As I explained last year, a lost time accident with us is an accident wherein the injured man is not able to return to his regular work, the next day-the day following the injury. So this represents (indicating) the lost time accidents per thousand shifts worked. We had one fatality in the twelve accidents which is reflected in the severity rates, which are also based upon thousand shifts worked instead of per million hours. The reason we are on the thousand shifts worked is be¬cause the Copper Branches of the Phelps-Dodge Corporation are all kept that way, and we are on the same basis for easy comparison.

Jan 1, 1935

By Andrew Franklin

The eightieth regular meeting and convention was called to order by the President, John T. Atkins, at 9:15 a.m. Monday, June 25, 1984 in the Colorado Ballroom of the Marriott's Mark Resort in Vail, Colorado. President Atkins welcomed the members and their guests to the convention and noted that the annual business meeting would be held Tuesday afternoon at 2:00 p.m. in the same room. A convention update was made by the Conven¬tion Liaison Officer, Loren V. Linville. This was followed with a program report by the Program Chairman, Doug Ingram. The chair then called on Clifford Barrett, Upper Colorado Regional Director of the Bureau of Rec¬lamation of the United States Department of the Interior. He presented the Bureau's Citizen Award to RMCMI former president Ira E. McKeever for his outstanding contributions to the joint private/ Federal effort and the open planning process for AQUATRAIN. According to Barrett, "from 1981 to early 1984, McKeever led private industry work in the AQUATRAIN project, a proposal for a 1,400 mile long pipeline system. AQUATRAIN was conceived as a possible alternative to solve the government's problem of rising salinity levels in the Colorado river, as well as the private sector's need for a more economical coal transport method. The Citizen Award cites McKeever's efforts in developing a model for future cooperative ventures between government and industry that can benefit the nation." Following this presentation, the formal program of the 80th meeting and convention began with the president, John Atkins, introducing the convention kickoff speaker, Andrew Franklin, President of Nerco Mining Co., Inc., followed by the convention keynote speaker, Dr. Margaret N. Maxey of the University of Texas. These speeches are printed in this Proceedings together with those of all other convention speakers. I'm Andrew Franklin, President of Nerco Min¬ing Company, and I'm delighted to be here to kick off the annual convention of the Rocky Mountain Coal Mining Institute. This has always been a very special convention in my eyes and I'm sure this year's will be no exception. I am also here to share my thoughts on the western coal industry and how we're all affected - for good and bad - by public policy decisions. Although the title of my talk is "Western Coal: An Industry Under Siege," I believe a more accurate title might be "Western Coal: The Pit and The Pendulum," because of the wide swings in public policy and coal development in the past 15 years which have cut a zigzag path for growth over this period. As one of the nation's largest coal producers, Nerco is well aware of the problems facing western coal production. Nerco Mining Company is the western coal mining subsidiary of Nerco Inc. We have been "in coal" for more than 25 years through our parent company, Pacific Power & Light. To state my conclusion at the outset, I feel it's extremely important that consistency and common sense should guide our national policy for the development of valuable energy resources. In particu¬lar, we must reduce the wide swings in government policy and activities which have affected energy development. In short, we must decide what kind of game we're playing so that the "players" and the "referees" can keep their eyes on the "ball." Business today faces two main types of uncertainty market uncertainty and public policy uncertainty. As businessmen, we expect and are used to facing the familiar challenges and uncertainties of the market in which we operate. Over the past 10 years, the market has appeared to be bullish on coal. But the facts make our future less rosy. Last year, western coal producers faced over 50 million

Jan 1, 1984

President Heiner opened the final session of the Institute at 9:30 a.m. Frances Leonard read the report of the Auditing Committee. Motion made by Stan Shubart for acceptance of audit and approval. Seconded and carried. R. R. Williams of the Resolutions Committee presented the following resolutions to the, group for their approval: RESOLVED: That the members of the Rocky Mountain Coal Mining Institute, in convention assembled, hereby ratify and confirm all official actions of the Officers, the Executive Committee and other committees of the Institute between and including July 3, 1963 and July 1, 1964.

Jan 1, 1964

The opening session of the Forty-seventh Meeting of the Rocky Mountain Coal Mining Institute was called to order at 10:00 o'clock a.m., Thursday, June 7, 1951, in the junior Ballroom of the Hotel Utah, Salt Lake City, Utah, with President Arthur B. Foulger presiding. PRESIDENT FOULGER: We are a little bit late getting started, gentlemen. We have a few more members out there to register and we will wait just a few minutes until they are finished and then we will begin. The Honorable Earl J. Glade won't be here until 2:00 o'clock this afternoon. I understand lie was unavoidably detained so we are going to go down this program pretty rapidly when we get started, but we want to wait until those gentlemen still unregistered come in. Gentlemen, we will try and start now. Mr. Whiteside suggests that the minutes for last year probably should be read. However, they were published in the proceedings for last year, so I presume it will be just as well to dispense with the minutes and get going here before we lose too much time.

Jan 1, 1951

The Wednesday morning session was opened by President Joe Ward at 9:30 a.m. He complimented Walter Mueller, Program Chairman, for the excellent job he did as head of that very important committee. He also thanked all those on the various committees, speakers, and all who participated in making the 1972 meeting a success. He called on William S. Landers, Chairman of the Auditing Committee, to give his report. He read the report and asked for a motion of approval. Motion was made, seconded and approved. (See Treasurer's report on page 5.) A. E. Pagnotta of the Resolutions Committee read their report as follows: RESOLVED: Whereas, since the 67th Regular Meeting of the Rocky Mountain Coal Mining Institute. held at Park City, Utah, the Institute and the coal mining .industry has suffered the loss through death of service and fellowship of the following members: W. H. Carson James Dalrymple Edward H. Denny A. B. Foulger Thomas E. Graham G. R. Harris Frank Markosek Anthony C. Moschetti Harry Swihart Franklin B. Thomas

Jan 1, 1972

By Franklin P. Wood

Unnumbered ages have passed since the time when nature's laboratories were working without the aid of capital or labor unions assisted only by earth's cooling crust and old Sol's rays, to lay the prodigious coal beds of the earth and distil the oils which now furnish the basis for the world's great industries. Strangely enough rays from the same old sun probably somewhat diminished in intensity are still drawing from earth to clouds the water that will run down hill and through man-made devices produce energy to compete with that made with the products created in ages past. So now we find that within the past century vast human industries have grown up around the products of these agencies and here we are today discussing the many problems connected therewith and among the others the subject of this paper, which is essentially the relation of COAL to OIL in industry. The problems involved are those of human relationship and are not fundamentally unsolvable when engineering skill and knowledge is properly applied. The last few years has developed a brand of pessimism that is especially prevalent in the coal industry, at any rate in the west where we come in contact with it. In any general discussion with coal men, a very short time only is required to bring out the feeling or expression that the coal business is on the rocks and the reasons run the gamut of human deviltry. We have heard that in the not far distant past corn was so cheap that the farmers were compelled to burn it and thus deprive the coal mines of their well earned right to sell coal for this purpose. We have heard that the flood of oil is so vast that it was being burned in preference to coal, and to heap insult on injury that the rail- road locomotives were burning oil in order to pull coal away from the mines. We have heard that the union was responsible for all the woes to which the industry is subjected. We have heard that the family tin lizzie is so depleting the family exchequer that coal could not be purchased and if purchased could not be collected for. We have heard that producing mines are so numerous that the profits are a negligible quantity. These are but a few of the reasons assigned for making the coal producers a class of pessimists which is not good for the industry. All these reasons given and all the others must be taken collectively and these are not the cause but the effect of a rapidly changing civilization. An analogy may be found in the experience of many of us in the electric industry a few years ago. You may remember that less than 20 years ago the high efficiency Tungsten electric globe was introduced. It was so much more efficient than the old carbon lamp that only one-third of the current previously required was needed to produce the same illumination. Consternation seized the ranks of electrical men who had little or no vision, for the out- look was that so little current would be sold that everyone would be bankrupt. This limited vision, however, did not prevail, for all engaged in the industry spurred on by necessity, accomplished many of the things that we are now enjoying the fruits of be- cause the electric industry has grown and is growing by leaps and bounds and every highly efficient improvement is greeted with rejoicing. It is well known that when the old type of carbon arc lamp began to be replaced by modern units the manufacturer of carbon rods thought his doom was sealed and yet these same manufacturers have so adjusted them- selves to conditions that the dry battery business of today is of vastly greater volume and profit than was the carbon rod business of the past. Of course, there are industries that should not have survived anyway that have gone down and out to makeway for vastly improved conditions and can

Jan 1, 1925

By M .. K. Stewart

(Here follows descriptive movie.) CHAIRMAN KNOX: Thank you very much, Mr. Stewart, for this wonderful paper and picture. We are indebted to you. It certainly is the most interesting thing I have ever seen in connection with wire rope, except paying for it. I think there are a lot of questions that could be asked to bring out some points that we are not generally understanding of. Are there any questions at this time? I know Mr. Stewart will be glad to answer them. Come up to the front, Mr. Stewart. MR. STEWART: That's all right, thanks. CHAIRMAN KNOX: If there are any questions, let us have them. (No response.) Well, we will pass on to the next paper. CHAIRMAN KNOX: Our next paper will be "Self-Preservation, with Some Comments on Mechanical Loading," by Benedict Shubart and Charles Schloss.

Jan 1, 1935

By A. W. Dickinson

Since the day when one of the most progressive of our flat-head for- bears used a pry pole to loosen large rocks to crash upon the head of his, enemy, thereafter making notes of his performance on tablets of stone, the arts of mechanicalization have developed and progressed to the benefit of mankind. In the early coal pits of England the crudest of tools were wielded in the most slavish of toil to win a very small amount of product. In our own country it is but a few years since coal was hewn by negro slaves in the mines of the southland. The past thirty years have brought the use of the mining machine, power drill and locomotive, and we now stand on the brink of the coal mining era that will change the toiler of the mines into a skilled mechanic and render far more safe the winning of the fuel necessary to the nation's need. The ingenuity of our citizens has made it imperative that coal be produced at a lesser cost. Vast supplies of fuel oil have been developed; enormous resources in water power are turning the wheels of many mills and, most commendable but distressing to the coa.1 producers, the high price of coal has resulted in efforts and accomplishment in fuel economies unheard of a short five years ago. The railroads of the United States alone in 1924 accomplished more hauling with $30,000,000 less in coal bills than in 1923. The loading of coal by machines has been under investigation and trial for some time past and in an effort to have its men informed of the practice of the eastern coal fields, The Union Pacific Coal Company sent the writer through a number of states to view as many operations as possible. Notes were taken of machines and processes seen and time was spent with engineers of the various coal companies; also with the United States Bureau of Mines Engineers, particularly Mr. Edwin H. Johnson, who devoted one year to the most careful study of the mechanical loading of coal. The writer wishes, at this time, to acknowledge the helpfulness of the information acquired through contact with Mr. Johnson.

Jan 1, 1925

By Paul Schmechel

This time of year, our lawn is host to goodly numbers of birds - robins, English sparrows, finches of various flavors and some whose names I don't know. We lure them with a feeder in our backyard and I'm sure Patti and I spend several minutes a day watching them through a picture window that overlooks their coming and going. And, while the picture window supplies us with a constantly changing view, it does not treat our winged friends nearly so kindly. You see, at certain times of the day, reflections on our window feed back to our birds a mirror image of the backyard. Lifting off from the bird feeder, they see before them what is behind them. And, not infrequently they fly straight into the window. They stop abruptly, of course. It has to be quite a shock to discover that what is behind you is not the same as what is in front. At this point, I might be tempted to say something about bird brains - except for the fact that we humans also are prone to deceptive images thrown up by the past. Today, I think we hear a great many voices painting past images as they look to the future. We hear that the price of oil soon will rise to its former elevated position; the price of copper will bounce back; a hungry world soon will escalate the demand for food and our agricultural industry will be back in the black. In fact, we can hear hope from many voices telling us that our major resource-rich, basic industries are poised to fly up. I can hope that the voices are right, but I keep thinking that those expressions come from people seeing false images. Most certainly, it is more comfortable to see the past, rather than acknowledge that the world economy is being restructured and that the restructuring is affecting the Rocky Mountain states profoundly and negatively. The worst mistake we could make may be to place too much credence in the images from our past. We can be lulled into a dangerous complacency. What we need is a tighter belt and the will to do some serious bootstrapping. Before proceeding, I would make two points: First, it is not my intent to be a prophet of doom. But I do think we need some healthy doses of realism, if we are to avoid the shock of flying into a false future. Second, by now you have detected that I have choosen to diversify the assignment you handed me on utility diversification. As I proceed, you soon will see that the roots of diversification for many utilities lie in the subject that we ponder now. We could begin in many places, but let's start with energy. It is pervasive in our businesses and industries. We all use it. And, despite conventional economic wisdom, we are using less of it. The price is down, but we have not reverted to our profligate ways. That is true whether you look at the industrial customer or the residential consumer. As a nation and as a people, we have learned to do more work with less energy. A few statistics illustrated the point. If we use 1973 as the base year, energy use in the United States has declined almost I percent. If we examine the year of peak energy use, 1979, the decline approaches 7 percent. Let's look at it another way. In 1973, for every dollar of gross national product, the United States consumed 27,100 Btu of energy. Last year, 1985, the comparable figure was 20,700 Btu - a decline of 24 percent. So, not only are we using less energy, but we are using it more efficiently. Even though the price of energy has declined, we are unlikely to use substand with natural gas and petroleum consumption. Use of natural gas has dropped almost 21 percent since 1973. Petroleum consumption has declined 1 I percent since 1973 and almost 19 percent since 1978, when the U.S. used a record quantity of petroleum. We also know there's been no appreciable change in amounts of oil and gas used since 1981. We weathered both a sharp recession and a healthy recovery without altering the amount of those fuels used. That the use of oil and gas dropped sharply, while the total use of energy merely slumped a bit is easy to explain. The use of coal, nuclear power and hydroelectricity from 1973 through 1985 increased almost 48 percent. Some people will tell you that the large decrease in the price of oil and gas will result in increased demand that will displace coal, nuclear and hydropower. In turn, demand will force the price of oil and gas upward. I doubt it. From the poking around I've done on the subject, I suspect there may be some short-term displacements, but they will be, for the most part, cancelled out by declining use among existing customers. For instance, we all know what has happened in the automotive sector. In 1973, the average U.S. automobile made 13.1 miles to the U.S. gallon of gasoline. In 1984, the most recent available statistic, the average auto made 16.94 miles to the gallon. That's a 19 percent improvement. Because annual miles driven per automobile are essentially unchanged over the period and the number of cars on the road is not increasing, we are witnessing a drop in this segment of the petroleum market. That trend will continue. Now, let's look at energy consumption patterns still another way. Between 1973 and 1985, consumption in the residential and commercial sectors of our economy increased total energy use by 11.2

Jan 1, 1986

The Wednesday morning session was called to order by President Lewis at 9:00 am, He called on Bob Wilson to conduct the business meeting. In the absence of any of the Auditing Committee, the treasurer's report, which had previously been examined by them was read. He asked for a motion of approval. It was made, granted and approved. The Resolution Committee was called on to make its report. Mr. Shirl McArthur read the following report: (1) "WHEREAS, the Pneumoconiosis or Black Lung provisions of the Federal Coal Mine Health and Safety Act which have been construed and administered largely as a welfare program rather than as just compensation for occupational disease has resulted in enormous expenditures and commitments from the Federal Treasury, WHEREAS, the imposition of the full cost of future welfare oriented black lung awards on coal operators without regard to workmen's compensation standards and without due process in granting benefits is grossly unfair and discriminatory to the coal operator and places an undue burden on the present cost of coal,

Jan 1, 1973

The 75th Regular Meeting of The Rocky Mountain Coal Mining Institute convened at The Mark Conference Center, Lionshead Village, Vail, Colorado, and was in session at 10:00 a.m. Past President, Shirl C. McArthur, President and General Manager, American Coal Company, Huntington, Utah, called the meeting to order. The membership was asked to stand and pledge allegiance to the flag. He introduced President Robert E. Murray, President, Western Division and Subsidiary Companies, The North American Coal Corporation, Bismarck, North Dakota. A biographical sketch follows: Since 1974, Mr. Murray has been President of the Western Division of The North American Coal Corporation, as well as President of The Falkirk Mining Company and The Coteau Properties Company, wholly-owned subsidiaries of North American. Previously, Mr. Murray, who has been associated with North American for twenty- three years, served as Vice President-Operations, Vice President - Eastern Division, and Assistant to the President of the Company. In these positions, he was responsible for North American operations in Pennsylvania, North Dakota and Utah.

Jan 1, 1979

By J. J. Craron

MR. J. J. CRARON: If Ross Weber rings that bell of his, I think I have a few secrets on him that I will tell. It is not such a long time ago when the sales and executive departments of the coal industry were constantly urging the operating department to increase their output, and this cry for increased production resulted in vast development work and increased capacity to the point where the operating departments are today in position to produce coal upon sudden demand far in excess of the ability of their sales departments to dispose of it. So today our ability to produce coal is away ahead of our ability to market it. There are many reasons, of course, for this condition. First, the present economic situation, which has prevented even a normal consumption of coal. Secondly, the over-development and production of every commodity and industry as the result of war time and post-war time prosperity. Thirdly, the inroads made by competitive fields, particularly oil and gas, because of the desire of the public for automatic heat.

Jan 1, 1934

T. T. READ, BUREAU OF MINES: Mr. McAuliffe has asked a very practical question. Expressed in another way, the question is: If we have decided to use rock dust to prevent coal dust from exploding, have we got to take rock, that is, solid material,, break it up and finally grind it into dust (and fine grinding is very expensive), or can we take material that is already in a pretty fine state of subdivision and thereby save the expense of pulverizing it? Most of the preceding discussion has been from the view-point of practical experience, and I should like to suggest that we have not had enough practical experience in rock dusting to be able to answer this question, from the viewpoint of experience, with the degree of definiteness that Mr. McAuliffe desires. With your permission I will discuss the matter briefly from the theoretical standpoint, because after all the theoretical considerations, insofar as we understand them correctly, will apply to every' case, whereas in coming to a decision on this matter it will be necessary to take into consideration local conditions, which will necessarily vary in every case. Considering the matter in a rather elementary way, the first point is: What makes coal dust explode? The air of this room is full of dust at the present moment, even though we do not notice it. If you were to close up the room for a week, enough dust would settle on the floor so you could write your name on it. Of course, the dust which is in the air of this room is not coal dust but even if it were coal dust and you were to bring an open light in' here we all know that the dust would not explode. The reason for that is that the dust particles are not close enough together for the flame to propagate itself from one to the next. You will probably be able to see in the demonstration in the gallery on Saturday that the coal dust explosion is practically a very rapid burning of the dust. When you light one piece of dust it burns and gives out heat and if there is another piece of dust close enough to it so that the heat from the first piece is able to bring a second piece up to the burning temperature, then the flame will propagate itself through the mixture. But, if the particles are so far apart in the air that the' heat from one particle is dissipated before it reaches an adjoining one, and is therefore not able to bring the second particle up to the burning temperature, then the flame will not propagate. To get a coal dust explosion, it is not sufficient to have coal dust suspended in the air. The coal dust particles must be close enough together in the air so that the heat from one burning particle is able to heat the adjoining particles up to the point at which they will burn. There has been some discussion of the size of dust particles that will cause an explosion to propagate, and it has been pointed out that the minus 200-mesh dust is the most dangerous, and that particles coarser than 20-mesh will not propagate an explosion. There are two reasons for that. A large particle has very much smaller surface in proportion to its weight than a small particle has. You know the old story about the Indian who when asked how he could go around in cold weather without any clothes on said that an Indian was all face. A 200-mesh particle is almost all surface and there= fore is able to burn almost instantaneously, which means that it gives out its heat almost instantaneously, whereas a large particle with less surface in proportion to its weight burns more slowly, gives out its heat more slowly, and the heat has more time to be dissipated. The second reason why coarse dust does not easily propagate a flame is because it is so hard to make it

Jan 1, 1924

PRESIDENT LITTLEJOHN: Gentlemen, you have heard Mr. Dyer's paper. The meeting is now open for discussion. MR. NORMAN: I would like to ask the gentleman what is the distance between your crosscuts for the ventilation of rooms and entries in the state of Utah?

Jan 1, 1925