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MR. GIBSON (continuing): In connection with the coal from this mine, I will say that it is not a very dirty coal. The vein where most of the coal comes from is about eight feet thick, and two feet from the bottom there is a small boney band about two inches thick. The breaking shot has to be placed over the, band, therefore breaking the boney into fine particles which goes off with the slack. This coal is a very good domestic coal and the slack is in great demand for various power, plants, such as sugar plants, smelters and other industries, but where this, boney is broken up and goes into the slack, it is very injurious in effect and retards the sale of the slack. Therefore the Spring Canyon Coal Company went to the expense of' building this plant, costing over $250,000, just in order to get that, two inches of boney coal out of the rest of the vein. The market in, Utah is very critical, and in order to sell coal, the product must be thoroughly clean in every way and, as Mr. Murphy says, I believe they have succeeded in making a very good commercial product. In any event the Spring Canyon Coal Company put out more coal than any other one mine during the last year, 1924, they had the largest production. I thank, you. (Applause). PRESIDENT MARKS: With the assistance of Mr. Robinson and Mr. Miller, I am sorry you could not get the pictures a little better synchronized with the story. MR. F. C. MILLER (Chief Chemist The Colorado Fuel & Iron Company, Pueblo) : We had seven slides to show eighteen different views on the screen and we did remarkably well. (Laughter.) PRESIDENT MARKS: Is there : any further discussion on this paper? MR. G. B. JONES (Mining Inspector, Victor-American Fuel Co.) : I would like to ask a question on the

Jan 1, 1926

By Sam Andrews

Mr. President, Officers and Members of the Rocky Mountain Coal Mining Institute: This is my first attempt to prepare and read a paper before your association. The Rocky Mountain Coal Mining Institute, I understand, was formed for the purpose of increasing knowledge relating to coal mining in all its various branches by study, research and discussion. In writing my paper, I have tried to be as practical as I can, at the same time, present my arguments so that they can be easily understood. When I use the word science, I mean organized common sense. I humbly ask my hearers to be a little patient, while I read my paper, and be "to its faults a little blind, and to its virtues a trifle kind". Western Europe is said to be the cradle of the coal mining industry. We are told that the Ancient Britons were acquainted with the use of coal long before the Romans invaded and conquered their country. The Romans were never too proud to learn from the outer barbarians, and possibly acquired the precious secret from them: We are told that it was not until the 13th century, that the coal mining industry, assumed any noticeable importance in Britain, and on the Continent. In the year 1259 Henry the 3rd granted a charter to the freemen of New Castle on Tyne, allowing them to mine coal. For a long time it was used in the arts and manufactures only, wood continuing to be the common domestic fuel. As has been the case with almost every great benefit, the introduction of coal as a fuel was stoutly resisted at first, and we find its use prohibited in the city of London in the reign of Edward II, by Royal proclamation ; which was soon discovered to be injurious and foolish, and consequently withdrawn. It is interesting perhaps, to know how this Royal proclamation was brought about. A lady of the Royal household was riding in her coach one day through a village in which coal was burned as a fuel, and she suffered such a cough by inhaling the coal smoke that she decided to call a council of suffragetts, who ultimately decided that the burning of coal was injurious to their health and complexion. They drafted out a petition and presented it to the king, who speedily issued the order that no coal was to be burned in the city of London. The penalty for disobeying this order was death by hanging. We are informed of one poor man who continued to burn a lump of' coal on his fire in winter time; he was arrested, sent to prison and condemned to death; the judge in passing the sentence solemnly stating that if he was not allowed to get a fire that was hot enough in this world, he felt that he surely would be allowed one in the next.

Jan 1, 1921

By C. P. Crawford

In the current issue of Link-Belt News is this quotation: "Advancing waves of other people's progress sweep over the unchanging man and wash him out." As we look over the industrial world today we are struck by the many waves which are sweeping over backward industries. Mergers are being consummated in all lines of endeavor. General Motors are making radios and the Bendix Brake Company are making airplanes. Railroads which twenty years ago were called to account by the Federal Government for their efforts to form combinations are today being ordered to combine. But what is of immediate concern to the coal industry is the fact that there is now in existence or in project a total of 3,641 miles of pipe lines to carry natural gas to most of the country's industrial centers. This is the wave of progress which is sweeping toward you and me. If we are to grasp the significance of these many changes, we must widen our vision so that we may learn some- thing from 'the other fellow's experience. The first lesson is that cost of production alone is not a measure of profit. It is an interesting fact that the production of an article represents a definite loss until that article has been sold for a price in excess of its total cost, and the money is in the hands of the producer. If this is true, then the selling price is more important than the production cost.

Jan 1, 1930

will be held at COSMOPOLITAN HOTEL DENVER COLORADO June 3,4,5, 1931

Jan 1, 1930

MR. HARRINGTON: I would like to ask Mr. Bottomley if they fire their shots while the men are in the mine? MR. BOTTOMLEY: No sir; the shot-firing law in our State requires the shots to be fired after the men are out of the mine. We fire more shots than we did under the hand method of loading. Where formerly four holes were drilled, now we drill eight, using the same amount of powder as we did formerly, perhaps a little more, but we use a slower grade of powder. CHAIRMAN LITTLEJOHN: Any further discussion, gentlemen? MR. GIBSON: Mr. Chairman, I would like to ask Mr. Bottomley, if, in his shot-firing system, as I understand it, he has a very high coal and is working something like eleven feet? MR. BOTTOMLEY: Something like that. MR. GIBSON: I read the article that you referred to. Did you use both the first and the second delay explo¬ders in shooting the coal? MR. BOTTOMLEY: We use the ordinary fuse. MR. GIBSON: That is what I wanted to find out; whether you use the delay exploders and the detonators. In Utah, we are getting away from the fuse altogether, because we do not think it is accomplishing anything to use the electric light on the cap, and' at the same time shooting with fuse. We are defeating the object we might gain in using the electric safety lamp. That is a point that might be discussed a little further. MR. E. H. JOHNSON, The Coloder Company: I would like-since it is a general opinion that mechanical loading breaks up the coal, to ask Mr. Bottomley, if he finds a larger percentage of small coal, or how much, through the use of the mechanical loaders? MR. BOTTOMLEY: We do not find any great difference. In fact, we have succeeded in improving our lump coal percentage, and that is important, because it is largely domestic. At first, when the machines were installed, the boys shot the coal too hard, and we fell down a little, about two or three per cent, the first month, in our lump percentage, and we tightened up a little and changed our methods in shooting and got on to the stunt of drilling more holes and getting a slower grade of powder. We could not load as much coal in one day as we could before, but we did succeed in in. creasing our lump coal percentage four and a half per cent over the hand method, and that is quite a factor-quite an important factor and since our domestic trade is over with, we loosened up on the shooting and we are running about the same as we did with the hand loading, maybe a half per cent more, or one per cent, but pretty much the same. MR. SHUBART: Your coal is very high? MR. BOTTOMLEY: Yes. MR. SHUBART: Have you tried sunbbing the coal before shooting? MR. BOTTOMLEY: No, we have not tried that. It is very hard coal to shoot; we have no defined cleavage in our coal. It is the worst coal I ever saw to shoot. We do not try to snub it. Formerly, as I said, the miners drilled four holes, pretty well up near the top, and then four holes down, within about three feet of the bottom. It is the same thing as a snub shot, and that we find is the best method for shooting the coal. We have not tried any mechanical device for snubbing as yet. SECRETARY SHUBART: At one mine I saw snubbing tried with a Jeffrey undercutter with a seven-foot Jeffrey bar. This mine, by the way, is very similar to Mr. Bottomley's condition. They have very high coal, so the snub cut is a small percentage. They cut a seven foot undercut and raise the machine on an eight inch tie and undercut five feet to give the effect of a snub cut, 14 inches at the front of the cut, and then six inches at the back of the cut. They made a very marked increase in lump. (The bug dust would be a small percentage of the total coal), and they increased the percentage of the slack at the same time. They found a decrease by reason of the easier shooting of about 15 per cent in their slack. In other words their nut and lump coal ran considerably higher and their slack decreased 5 per cent with the snubbing cut. Mr. Bottomley, I believe, understands those conditions.

Jan 1, 1926

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

The 70th Regular Meeting of the Rocky Mountain Coal Mining Institute convened at the Steamboat Village Inn, Steamboat Springs, Colorado, and was in session at 10:00 a.m. The session was called to order by Past President O. F. Lewis. Consultant, Colowyo Coal Co., Denver, Colorado. Mr. Lewis introduced President A. F. Geiger, Manager, Navajo Mine, Utah International, Inc., Fruitland, New Mexico. Following are Mr. Lewis' remarks: Ladies and gentlemen, members of the institute, guests and friends, welcome to Steamboat Springs and the 70th meeting of the Rocky Mountain Coal Mining Institute. From all appearances this is our largest meeting and should be the most successful. When I last spoke to you I was President of Colowyo Coal Company and the Rocky Mountain Coal Institute but that has changed. Colowyo Coal Company was acquired last Dec. by W. R. Grace & Co. and operates as Colowyo Coal Company, Division of W. R. Grace & Co. I am confident these people will make a worthwhile contribution to the coal Industry.

Jan 1, 1974

By R. A. Marshall

Much has been written by men connected with the coal mining industry, and mining laws have been enacted for the safety of the men employed in the mines, and for the protection of property connected therewith. It seems almost impossible for anyone to select a subject that has not already been read, discussed and put into effect, especially in the coal mines of Western America. There is, however, a subject of much interest to the mining public, and to which I have given a great deal of study and consideration, and which I believe will be received by this convention, and will be given due consideration in the future in applying it to the safety of the mine,- "Efficiency in Shot Firing." Beginning with 1865, and for a period of 28 years in the state of Colorado, the annual reports of the chief inspectors show that 1159 coal miners were killed in the following manner: Five hundred eighty-two by falls of rock and coal ; 517 by gas and dust explosions; 6o by careless handling of explosives and the shooting of coal by the, individual, miner. It is my firm belief that 75 per cent of these fatal accidents might have been avoided, if a safe and proper shot firing system had been installed, at each and every mine. This may sound unreasonable, but I believe that the blasting of coal by the individual miner, and the use of black powder, squibs and fuse has, in reality, caused the death of many miners, from shock after blasting, the shooting out 'of timbers, and working in powder smoke, which fatal accidents were attributed to falls of rock or coal. These conditions led the people of Colorado, through their representatives of the General Assembly of Colorado, to enact a new coal mining law, and in 1913 this law became effective, containing twelve sections devoted to the subject of Efficiency in the System of Shot Firing. During the period 1913 to 1920, the employment of a shot firer, the use of permissible. powder, and the electric hand battery has resulted in safer mines, safer miners and safer shot firers, and I believe every coal mine in the state should employ first-class, certified shot firers, use permissible powder and fire the shots with an electric hand battery. I believe where gas generates in dangerous quantities, which is generally determined by inspection of the mine, and the daily report, the shooting in. such a mine should be done by electric battery located outside of the mine. Where permissible powder is used, I have seen the shot firer start down the mine with a belt around his waist containing one hundred caps, a safety lamp to test for gas, and an open light to ignite the fuse. Would it not be much safer for the shot firer if he used the electric hand battery? In non-gaseous mines where black powder is used, I have. seen the miners carry fuse into the mine, and shot firers have been known to partly tamp the holes, which was

Jan 1, 1921

PRESIDENT WETZEL: The meeting will come to order. We are pleased to see a few of the more hardy survived last night's-ordeal and are present this morning. The Secretary has some correspondence which he will read. SECRETARY WHITESIDE: Gentlemen, I have a couple of telegrams and a letter which I would like to read to you at this time. First, a telegram addressed to Mr. Wetzel: "Regret greatly necessity canceling my plans to be present at meeting. Appreciate your conveying my best wishes to members for successful and profitable session.

Jan 1, 1942

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

PRESIDENT WHITESIDE: The chair will now throw the meeting open to discussion. GEO. B. PRYDE: In the old days at Rock Springs we had electric plants situated about half a mile from our mines; we had small boiler plants; we had an electric plant with about 600 kilowatt capacity. About ten years ago we discarded the old steam plants and started building towards a centralized power plant. We now have three 2,500-kilowatt turbine generators and one 1,000, and our peak load is about 7,000 kilowatts. We have had to rebuild the old power plant, scrap the old machines, and install water tube boilers. We did this as a matter of economy in a small local plant we had years ago, and it has grown to be a large central plant, supplying power for about 20,000 tons of coal daily, and distributing this power within a radius of twenty miles. We have found this method of power to be more economical than with the old plants, and the people who buy power from us in the Rock Springs field say it has been to their advantage also. We found this last year, when we had to shut down for five months, that that plant was the only plant operating in the Rock Springs field, supplying all the power, running of fans and pumping during the time the mines were shut down, and it helped the situation very much. We had an old wooden building which we had to tear down, raise the walls, and put on a steel roof; had to rebuild the boiler room and rebuild the boilers. The water situation at Rock Springs has never been very good; we get our water from wells 250 to 500 feet deep, and use one and one-quarter million gallons a week. We have two large spray ponds and we have gotten along well. There isn't any comparison between the central power station and the old method of making power. (Applause.) FRANK YOUNG: I listened with a great deal of pleasure to the paper just read, and it struck me it was remarkable how a paper prepared by anyone could be so nearly identical and coincide so very near with the experience of another. It is just like some work I have had. I had the engineering part to do for the power plant for ten years, and I think at that time we did all of the things that he mentioned in his paper. Also his analysis of the cost of power seems to me exactly right. If I had gathered the figures and made the statement myself I think it would have been very much the same as was read. The recommendation that it is better to buy

Jan 1, 1923

George B. Brennan, Secretary-Treasurer, Imperial. Coal Company, Denver, Colorado, opened the third session of. the Sixtieth Regular Meeting of the Rocky Mountain Coal Mining Institute at 8:30 a.m., and introduced the first speaker of the morning with the following remarks: It is a pleasure to welcome you here this morning. We are indeed fortunate to have such excellent speakers this morning, some of the outstanding people in the mining industry. I know I express the feelings of the entire RMCMI when I say thanks to these excellent speakers for all of the time and trouble they have taken to prepare such talks and come here to give these presentations of some of the more modern developments with which we in the coal mining industry are concerned. The first speaker this morning is going to give a paper on a subject which has only recently caused one or two of unfortunate accidents. It hadn't, prior to this, been considered such a serious problem. However, the. Bureau of Mines is hot on the trail to insure there will be answers to this previously somewhat unrecognized difficulty.

Jan 1, 1964

Thomas J. Parmley C. N. Sweet T. C. Jenkins W. S. Iliff, Sr. Warren Bracewell L. C. White Fading away like the stars of the morning, Losing their light in the glorious sun; Thus would we pass from earth and its toiling, Only remembered by what we have done.

Jan 1, 1947

[Page Minutes 5 Low Temperature Distillation and Briquetting 8 F. C. Miller. Discussion of Mr. Miller's Paper 11 Track Bonding 15 D. C. McKeehan. Discussion of Mr. McKeehan's Paper 16 Report of Safety Committee 19 Wm. Littlejohn 19 P. F. Patterson and G. A. Knox 20 D. Harrington, J. C. Roberts and Jas Dalrymple 22 Discussion of Report of Safety Committee 27]

Jan 1, 1923

PRESIDENT MOSES: I think this will conclude our program for this afternoon, unless you have some- thing else. Mr. Holman, will you tell us what you are doing in the way of your local chapter, around Dawson? W. C. HOLMAN: (Chief Engineer, Phelps-Dodge Corporation, Dawson, New Mexico.) We have organized a local chapter of the Rocky Mountain Coal Mining Institute, and we invite all foremen, fire bosses, shot firers or anybody interested, either on the surface or in the mine. I think at the last meeting we had sixty to seventy men present. We hold meetings once a month; usually on a certain set Tuesday or second Friday of the month, or so on. We have a President, a Vice-President and a Secretary-Treasurer. There are no dues connected with it. We aim to take up the' papers that are presented at the various meetings of the Rocky Mountain Coal Mining Institute, and also any other subject that would be of interest, connected with our own mining operation. We usually ask two or three men to pre- sent papers, rather than one man. We find it difficult in getting one man to work up any subject, but two or three men work up very interesting papers. While we have just recently organized, we aim to have luncheons in connection with it, and possibly once a year a banquet or .some similar activity that we think would interest the men. We feel it is going to be a great help in carrying on the work of the present organization in presenting the activities around the mines. PRESIDENT MOSES: I thank you, Mr. Holman. Has any one any- thing to bring up at this time? MR. LITTLEJOHN: I would like to ask Mr. Holman if the Institute or the Chapter there is confined to Dawson alone, or open to other camps in New Mexico? MR. HOLMAN: At the present, Mr. Littlejohn, it is just confined to our own camp, although we intend to invite the members and the officials of the other camps later on, perhaps. Especially, if we gave a banquet, no doubt we would invite the others. MR. LITTLEJOHN: Is there any other Chapter in New Mexico besides yours in Dawson, Mr. Holman? MR. HOLMAN: None that I know of, right now.

Jan 1, 1926

The Morning Session of the Forty-Eighth Meeting of the Rocky Mountain Coal Mining Institute convened in the Little Theater of the Broadmoor Hotel, Colorado Springs, Colorado, at 9:30 a.m., June 4, 1952, Albert M. Keenan, Chairman, presiding. CHAIRMAN KEENAN: Ladies and Gentlemen, here we have our third and final clay of our program, and I wish to take this opportunity to thank all of you for your attendance, both in the past meetings and this one this morning... I am particularly delighted to see that we are all here this morning after the very enjoyable banquet last night. It is a little difficult to get people gathered up after such an occasion.

Jan 1, 1952

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

FEBRUARY 20TH. MORNING SESSION: The fourteenth regular meeting of the Rocky Mountain Coal Mining Institute was called to order in the Magnolia Room of the Albany Hotel. Monday, February 20th at 11 o'clock A. M., with the President, Mr. R. M. Magraw, in the chair, sixty-two members being present. The first number upon the program was the reading of the minutes of the previous meeting by the Secretary. There being no corrections or alterations, the minutes were approved as read. As Mr. Dan Harrington was unavoidably absent, his paper, subject: "Coal Mine Accidents and State Mining Law" was, by request of the President, read by Mr. J. Q. Lalor. Following this was a short discussion. There being no further business the meeting adjourned. AFTERNOON SESSION: The meeting was called to order in the Magnolia Room of the Albany Hotel at two-thirty o'clock P. M. with President R. M. Magraw presiding, fifty-eight members being present. Mr. Ben Shubart and Prof. J. C. Roberts were appointed a committee to draft and telegraph a message of condolence to Mr. E. S. Brooks of Rock Springs, Wyoming, on account of the recent death of his daughter. The com¬mittee submitted a copy of the following telegram, which was read by the Secretary: "E. S. Brooks, Rock Springs, Wyoming. We extend to you and your family our sincerest sympathies in your deep affliction. (Signed) THE ROCKY MOUNTAIN COAL MINING INSTITUTE." The following resolution was next presented by the Secretary and upon motion, duly seconded was carried by a unanimous vote: WHEREAS, it has come to the knowledge of this Institute that the Coal Mining Course of the Colorado School of Mines has been abolished; and

Jan 1, 1922

By K. L. Marshall

A facetious title was purposely given this talk, so that a formal paper would not be expected. TWO or three days ago, while discussing with Mr. Dickinson some of the details of the dust explosion demonstrations we are planning for this coming Saturday, I remarked that we would like to have as many people as possible see some samples of 20 and 200 mesh dust, so they would more fully understand just what was causing the explosions. Mr. Dickinson requested that I bring samples and screens and in this informal manner, give you all a ".close-up" of coal dust which is considered in Explosion Hazard reports. While sampling mines, for road, rib, and roof dust, in connection with safety service and hazard reports which the Bureau of Mines Engineers make at the request of coal operators, I have often been assisted by under- ground mine officials or other men of many years experience and on almost every occasion, while we were carefully brushing the very fine dust from timbers or coal surfaces, they would make some remark such as: "never had noticed this kind of dust, didn't know it was here", or "well, that's the first time I really understood what all 'this dust talk was about." Such experience makes me believe that the much published terms, 20 mesh and 200 mesh are just numbers to the great majority of both miners and operators. We are now going to have lesson one in the primer of coal dust explosions and I want to say, in all sincerity that a complete course in the hazards of mining is deserving of a place in the curriculum of the best mining schools of this country. Sample No. 1 is fine coal and dust and is a fair sample of what can be found every where in rooms and entries of a mine, as it is too small to be gathered up with a shovel and is left in the ordinary mining at the faces and is spilled along the entries in haulage. In this you will see some quarter inch coal, much eighth and sixteenth inch coal, in fact those are the sizes I find many people have in mind when they are asked about the dust made in mining. Although the sizes mentioned are the ones which seem to almost entirely make up this sample, such is not the case, for from 10 to 20% of such a sample will usually pass this 20 mesh screen and in Sample No. 2 we have 20 mesh dust. Result of many tests, supports .the statement of the coal mining division of the Bureau, that it is quite probable that coal over 20 mesh does not take part in any but the most violent of explosions and that all dust under 20 mesh may take part in any explosion. The largest particles in this sample will not be over .03 inches in their largest dimension and a pound of dust to a foot of average heading is very easily found in most every mine I have visited and usually a great deal more can be readily gathered up. It was .found early that the finer the dust the more dangerous it was for a given coal. So for the early explosion tests conducted by the Bureau a commercial pulverizer was used and it turned out a 20 mesh dust of which about 75% would pass 200 mesh. Some men question whether the ordinary mining methods made such a dust and so doubted the explosibility of the dust in their own mines. The question was well taken, and hundreds of dust samples were taken by the field men of the Bureau to determine the kind of dust being made in all methods of mining and all classes of coal. The result of such sampling showed some coals. resisted breakage more than others and that actual mine road dust, through 20 mesh, would show from 10 to 20% through 200 mesh, and for actual rib and roof dust through 20 mesh, they would get from 20 to 40% of 200 mesh dust. In testing the

Jan 1, 1924

PRESIDENT PRYDE: Any discussion on Mr. Poster's paper? MR. J. BEVAN: I would like to ask the gentleman how fine the dust has to be to cause an explosion? MR. T. FOSTER: According to the Bureau of Mines, it is claimed coal passing through a 100 mesh screen would be considered fine enough. That is all I can learn from the different bulletins. MR. BEVAN: Will the coal dust be that fine; going back in the empty cars on the tipple in the mine? MR. FOSTER: Possibly a great deal of it would be. MR. BEVAN: Will the coal dust be that fine, going back, in the empty the coal dust going back in the cars on the tipple, and into the mine? MR. FOSTER: In some places, they are wetting the cars at the tipple, -in the Rock Springs District, we have as the trip goes out, they have a big pipe, and they souse the car, and wet the load, and in some places, near the timbers; that helps to a certain extent. That does not absolutely eliminate it all, but it helps considerable. MR. WM. LITTLEJOHN (Utah Fuel Company) : I think we have all listened very attentively to the paper that Mr. Foster has just read. He has brought up a subject rather close to my heart, for a long time. He mentions particularly, the Scofield disaster, which happened the first of May, 1900; two hundred men lost their lives in the explosion; and I think it is generally conceded that is about the first time it had ever been brought to the attention of coal miners or operators that such a thing was possible, namely, a purely coal dust explosion. The term "Scofield disaster" is rather a mistake, in a way; while the mine that exploded at the time is in the Scofield District all right, it is now known, and probably was known at that time, as the Winter Quarters Mine, one of the mines which belongs to the Utah Fuel Company at the present time, and did at that time. This mine

Jan 1, 1924