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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

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

By David Scrymgeour

All low cost coal has been mined. Engineers are searching for a safe and effective way to mine coal seams' deep within the earth. The most modern of these is the RL, an acronym for Robotic Labor. Mining robots are programmed to do specific jobs but can think on their own during an emergency. MR's, or mining robots, usually have a same basic shape. A torso is mounted on treads. Designers chose treads because it gives the robot a great deal of mobility. The torso has two arms. One arm is equipped with a human hand. The other has a human-like hand. Mining is done underground. A small robot goes around punching holes in the coal. A small charge is inserted in the hole. The MR ignites the charge with his laser. It explodes after three minutes. The MR returns to the station where his battery is recharged. Mobile cement barricades are moved between the blasting area and other working MR's. After the charge explodes the barricades are moved to another area. The MR returns and cuts the coal chunks into pieces. Another robot comes and loads the coal and carries it to the loading bin. From there it is taken to the surface where it is weighed and shipped. The whole process was done by robots. Humans just supervise but help in an emergency or malfunction.

Jan 1, 1987

The Thirty-sixth, Regular Meeting of the Rocky Mountain Coal Mining Institute was called to order at the Shirley-Savoy Hotel, Denver, Colorado, Thursday, June 23, 1938, at 11:15 o'clock a.m., by Thomas Allen, Vice-President for Colorado, who announced that owing to the serious illness of Fritz Nyman's father, Mr. Nyman would be unable to attend the convention. Vice-President Allen welcomed the convention as a representative of Governor Ammons. Owing to the overlapping of a previous engagement, Mayor Benjamin F. Stapleton regretfully arrived too late to welcome the gathering in behalf of the City of Denver. Vice-President Allen selected Mr. F. W. Whiteside to preside at the morning session. On motion made, seconded and carried, the reading of the minutes of the Thirty-fifth Regular Meeting was dispensed with, inasmuch as they are printed in the proceedings. Chairman Whiteside suggested that the appointment of the personnel for the Committee on Resolutions, Nominating, Membership and Auditing be deferred until later in the meeting, and on motion made by Mr. Oliver, duly seconded and carried, this suggestion was adopted.

Jan 1, 1938

By D. Harrington

E. H. DENNY (United States Bureau of Mines, Denver, Colorado) In the absence of Mr. Harrington it is my privilege to read his paper, which is in his usual, forcible and sincere style, and it is within the province of this Institute, certainly, to go into it as it concerns safety and efficiency in mining. He brings out some points in his paper that, I think, are well worth the consideration of the Institute. The figures he uses were compiled by Mr. Adams, of the Bureau, and cover a five-year period. However, examination of similar Bureau figures for a ten-year period, or any other long period on other bases brings out similar results. The figures in this paper have been based on the million hours of exposure of accidents, and the figures based on three hundred working-man-day basis, or on tonnage, brings out similar results. This paper is entitled "Accident Record in Western Mines," and it is, in a way, an amplification of Mr. Harrington's letter which was read at the Glenwood Springs Meeting.

Jan 1, 1927

By James F. Howe

Modern civilization is centered around a small group of essential occupations, the three principal ones which are agriculture, mining and manufacturing. Agriculture might be called the most important of the three, as it has to do directly with the supply of food for the human race. Mining, however, is certainly next in importance, as it furnishes the supply of fuel and many of the raw materials used in manufacturing. Without mining, modern machinery and many industrial operations would be impossible. Mining takes advantage of the, natural resources in fuel and minerals that lie underneath the surface of mother earth, and while at times some of these metals are hard to find and mines come and go, mining must continue to increase. Mining is no longer a haphazard proposition but one calling for careful study and complete plans of operation for years to come. The shafts, power houses, rock dump crusher, concentrator, and other machinery must be located advantageously in order to enable owners to make a profit. Many tons of rock or mineral must be mined frequently to get one ton of concentrated metallic ore or metal itself. Economy in mining is just as essential as it is in manufacturing. The mining engineer of today is called upon to utilize every branch of engineering, and not only, is a wide: range of knowledge required, but ingenuity to meet the unusual conditions which are constantly arising from week to week. On account of the wide variety of information required by the mining engineer, some things with which he is in almost daily contact may be passed over with only a small amount of attention, provided everything is going well, in order that time and attention may be focused on what might be termed the more important features of mining operations. Because competition has become keener than ever, owing to overproduction at times of certain minerals, it becomes a matter of first, importance to understand as far as possible the factors which enter into the cost of production of any mineral which may be mined. In such times of overproduction, the high cost mine is forced to close down while the low cost mine may, if desired, be kept running constantly. In keeping a cost record, wire rope on account of its high first cost 19 coming into the lime light, and a comparison of records of one mine with another is now frequently made in order to see whether the rope service is satisfactory or not. Every rope maker, on the other hand, is interested in seeing that the rope which he produces gives the maximum possible return for the money invested. Modern mining owes much of its success to the use of wire rope for hoisting materials from beneath the surface of the ground. Deep mining would be impossible without the use of wire rope as a means of hoisting. A study, therefore, of rope problems in mining work and a discussion of the points which are beneficial to maximum life will enable the mining engineer, manager, or superintendent to keep his costs down to the minimum while at the same time he provides a suitable and sufficient safety factor for operations at all times. Mining might be defined as the extraction of coal, metallic ores, or minerals from below the surface of the ground. This definition does not cover what is known as, open pit operations or quarrying but covers the

Jan 1, 1922

By Edward Bottomley

Mr. Chairman and Gentlemen: I tried to get Benedict Shubart to have some fellow-some big fellow with a big voice-to read this paper for me, but he said there was nothing doing; [ ] that I would have to read it myself. I will try and not take up too much of your time. It is a pretty big subject, Mechanical Loading, and it covers a good deal of ground. I have merely touched on the high spots, as it were. A great deal has been preached and written in the last year or so about mechanical loading, and I doubt if any other subject in the mining industry has been discussed so freely and as often in the last few years. It is not the intent of this paper to dwell on the merits or demerits of any [ ] particular type of loader, that is, to say what the writer thinks is the most efficient or most inefficient machine. There are several types of loaders on the market to-day that are proving very successful in many mining districts. Some of these, five or six years ago, seemed to be a miserable failure from every standpoint, mechanically

Jan 1, 1926

The 69th Regular Meeting of the Rocky Mountain Coal Mining Institute convened in Manor Vail Lodge, Vail, Colorado, and was in session at 10:00 a.m. The meeting was called to order by Past President Joseph E. Ward, former District Manager, Denver Office, Coal Division, Joy Manufacturing Co. and now retired. Mr. Ward, after reading a brief biography of President O. F. "Os" Lewis, introduced him to the assembly. Biographical sketch read as follows: Mr. Lewis is President, General Manager, and a Director of Colowyo Coal Company. "Os" was born in Reno, Nevada. He attended the University of Utah at Salt Lake City, Utah, and later the Denver University in Denver, Colorado. His career in the Western Coal Industry started back in 1923 when he was employed by the Central Coal and Coke Company of Salt Lake City, Utah, as a clerk, then chief clerk and as a traveling sales representative for a period of 13 years. Later, in 1936, when that company was acquired by an affiliated company of Harris Coal Company, he was transferred to Denver as Assistant Sales Manager, Purchasing Agent and later as Executive Assistant to the President.

Jan 1, 1973

By J. J. Forbes

Gentlemen : It is a pleasure to come to Glen- wood Springs to participate in this meeting of the Rocky Mountain Coal Mining Institute an organization created to handle chiefly the economic questions dealing with the coal industry of the Rocky Mountain District. I am not unmindful of the many and varied problems confronting the mining industry of this country which is so general at the present time throughout the United States. By reason of the difficulties experienced in marketing the product of your mines, there is all the more reason for greater economy and efficiency in production. No industry can be efficiently operated without giving due consideration to the safety of the employees. Safety and efficiency are inseparable for the success of any industrial enterprise. While the Bituminous coal companies of the United States are doing splendid work in the promotion of safety, yet our fatality rate is exceedingly higher compared with that of foreign countries, and with greater cooperative organized effort on the part of mine owners, mine officials, mine workers, and state and federal governmental agencies having jurisdiction, much more substantial progress can be made in the future and a greater economic saving .to the industry effected, not taking into consideration the greatest and most important phase of safety, which is the conservation of life and health of all those who are engaged in the occupation of mining. You are concerned with freight rates, marketing of coal and similar operating problems. Yet have you earnestly considered the vital question that plays so important a part toward the success of any mill-

Jan 1, 1926

MR. STROUP: As soon as the mine workers realize that machine loading is going to be with us permanently, they will gradually accept the view that they, as well as the Mine Operators, will be in the end better off. Don't you find that to be true? MR. BUTLER: I do find that the antagonistic feeling that prevailed at the start is getting less and less and that the miners are co-operating with us. The machine is going to stay with us and I believe it is going to be better for them because instead of having the hard work of heaving coal, they will merely run the machinery that heaves the coal for them. I believe they all feel that way about the matter. MR. McAULIFFE: Mr. Farnham, out of his professional diplomacy, was very careful not to even mention his own machine by name. I would like to say a word about salesmen and about the men who develop the machines. They are perhaps doing more for the industry than we are doing ourselves. This applies also to the railroad business that I put a great part of my life in. If it were not for the energy, courage, and ingenuity of the men who manufacture machines, we would not occupy the advanced position we do today in the mining world.

Jan 1, 1924

By H. F. Nash

Coal is the basic necessity of our present-day civilization, and those engaged in the industry, whether miner, day-man, pit boss, tipple boss, superintendent, salesman or operator, have a direct responsibility to the public at large. Our country is blessed with a great supply of Bituminous coal, upon which it must largely depend for its industrial prosperity. Anthracite coal, in its relation to our economic situation, is a small factor, as its ratio of production to Bituminous coal is only about one-sixth. However, within the last ten years, electricity and oil have largely displaced the use of coal in industry, so that the use of Bituminous coal is decreasing, relatively, and the potential production of Bituminous coal has largely increased since the war. High wage scales and high freight rates make the delivered price of coal to the consumer so out of proportion to the cost of electricity and oil -and strikes make the supply of coal so uncertain-that industry is rapidly turning to electricity and oil. The energy in a ton of coal can be transported, by electric current, a distance of 250 miles for 78% of what it costs to ship the coal in bulk, by rail, in the East-and, for about 60% of what it costs in our section of the country. The use of fuel oil, distillate and gasoline, in industry, has increased by leaps and bounds. Especially was this noticeable during the strike this year, as the large packing plants in Kansas City, Omaha and Sioux City (that formerly used nothing but coal) are now practically all using oil. This also supplies to other industrial plants throughout our territory in Texas, Oklahoma, Kansas and Nebraska. Many railroads are using oil, as are also the smelters, cement plants, etc., etc. Ten years ago, 100% of the threshing in the state of Kansas was done with coal-today not over 25% of it is done through that means-and so it goes all along the line. The use of our coal is being yearly more restricted in industry. In the case of domestic consumption, the circle is also ever decreasing.' In small towns and on farms, kerosene, gasoline and wood are largely utilized for cooking. For the past four years, along any country road, it is a common occurrence to hear a buzz-saw cutting old fence posts or timbers taken from creek bottoms. Many thousands of tons of coal are displaced each year through the use of corn and cobs. In larger towns, gas plants have been installed, and many housewives use gas-in communities contiguous to natural gas, that is used for industrial and domestic purposes. The time has gone when industrial and domestic consumers or dealers are satisfied to buy anything that is black-competition among the coal-producing states is keen, and will become more so. Eastern and southern fields are turning out splendidly prepared coals of high quality, and with their lower freight rates to competitive territory, will entirely nullify the use. of our Western coal unless-

Jan 1, 1922

The Sixty-First Regular Meeting of the Rocky Mountain Coal Mining Institute convening at the Stanley Hotel in Estes Park, Colorado, was declared in session at 10:00 a.m. by Past President Claude P. Heiner, President, Minerals Development Corporation, Salt Lake City, Utah. Claude introduced Oren F. Bridwell, Secretary, Northern Colorado Coals, Inc., Denver, Colorado. His introduction of President Bridwell follows: Ladies and gentlemen, it is my privilege and pleasure to open this session of the Sixty-first Regular Meeting of the Rocky Mountain Coal Mining Institute. My particular assignment is to introduce to you (those of you at least who do not know him) our Acting President, who for now we will call "Brid."

Jan 1, 1965

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 Benedict Shubart

The subject of this paper may seem threadbare to, many of you, but even if I repeat what you already know, just smile to yourself and think how much wiser you are than your neighbor, for it is startling what a number of tipples are erected that violate the elementary fundamentals not only of good design but of practical operation. Possibly a coal screening plant is a simple plant. If so, we treat it like we do a great many other simple things. We treat it entirely too lightly and fail to take into consideration, not only the changes that may occur later, the conditions we may be compelled to meet as competition changes, but even the elementary physical conditions that exist right at the tipple site. If I get too positive over some particular point, don't blame me, but remember some of the heart-breaking experiences we have had correcting these omissions, trying to make a tipple do merely what it was designed to do, when the builder tied everything up in such a constricted space, that no room was left to get the results he must have. Perhaps some of the things will look too expensive. Don't say that you can't afford them. Many of them you can't afford to do without, and when you figure that a tipple is put up for possibly twenty years of operation, you can't afford to omit any reasonable precaution not only in taking care of the present, but in foreseeing the future. We will consider a tripple screening plant, suitable for Western conditions, capable of handling approximately 2,500 tons per eight hours. The largest screen sizes must be loaded into either open cars or box cars, and arrangement provided for screening and loading not less than five sizes of coal: lump, egg, nut, slack, dust, or any reasonable combination of these. As we are considering only the preparation of the coal, we will omit all consideration of the method of haulage, pit cars, methods of dumping, and will take the coal after it is in the dump hopper. The track arrangement will frequently be determined by the ground layout. Our sizes and tonnage can be loaded on three tracks, but four tracks are better. The two outer tracks should be left for loading lump coal, No. 3 track should be left for egg coal, and No. 4 track for loading nut, slack and dust. Where a fifth track can be provided, No. 5 track should be held open only for run-of-mine coal, to act as a storage where emergency coal can, be run, should there be any delay in the screening equipment or in changing cars. Track No. I should be used for loading lump coal into box cars only. Track No. 2 should be used for loading lump coal into open cars only, and may or may not be provided with picking table, loading boom, or both. Where picking is necessary, a picking table can frequently be put between the two "lump tracks, heading down track, pivoted at one end, so it may be raised or lowered to feed either open or box cars; with

Jan 1, 1921

Presiding-Thomas R. Young, President, Wyoming Fuel Company, Lakewood, Colorado. Mark Gillaspie, Vice President, San Marco Pipeline Company, Houston Natural Gas Company, Houston, Texas, presented a very interesting film-"Invocation in Coal Transportation-Black Mesa Coal Slurry Pipeline." (See index for printed text of Mark Gillaspie's remarks) * * * Kaye Kuhlmann, President of Citizens for Total Energy, San Jose, California, presented a paper-"Grass Roots Support for Energy Policy." (See index for printed text of Mrs. Kuhlmann's paper.) Mrs. Kuhlmann is President of Citizens for Total Energy, an International volunteer grassroots organization with the purpose of educating the public on energy alternatives. CITE strongly advocates responsible citizen participation in the establishment of energy policy.

Jan 1, 1980

The morning session opened at 9:00 a.m. and was presided over by Harold Levent., Manager Coal Activities, Cameron Engineers, Denver, Colorado. The first speaker was Dr. Joseph J. Yancik, Assistant Director-Mining, Bureau of Mines, U.S. Department of the Interior, Washington. D.C. Subject-"Coal Mining R&D Programs of the Bureau of Mines." (See index for printed text of Dr. Yancik's paper.) Joseph J. Yancik is Assistant Director - Mining for the Bureau of Mines, U.S. Department of the Interior, Washington, D.C. He is responsible for the Bureau's research programs in mining. Principal programs are the coal and metal mining health and safety research, mining extraction and excavation, tunnelling, explosives, mined land reclamation, mine fires and mine waste disposal. He administers these programs through four research centers and through outside contracts and grants.

Jan 1, 1974

By Kirk Nobis

Develop a Risk Management Plan for Your Mine ? Why? ? Measuring ? Managing ? Conclusion

Jan 1, 2006

The 77th Regular Meeting of The Rocky Mountain Coal Mining Institute convened at the Marriott's Mark Conference Center, Lionshead Village, Vail, Colorado, and was in session at 10:00 a.m. Past President, Loren V. Linville, District Sales Manager. Industrial Products Division. Uniroyal. Inc., Denver. Colorado, called the meeting to order. He introduced President, Edward F. Ziolkowski, Senior Vice President and General Manager, Energy Development Company, Hanna. Wyoming. A biographical sketch follows: Ed Ziolkowski is a 1953 graduate from the Colorado School of Mines with a degree in Engineer of Mines. His mining career began with Pickands Mathers Company in Gogibic Iron Range in Northern Wisconsin and Michigan. In 1961 he joined Texas Gulf Sulphur Company as Shaft Mining Engineer for their Cane Creek Potash Project near Moab, Utah. After serving as General Mine Foreman. Mine Superintendent and General Superintendent at Cane Creek, he was transferred in 1969 to Green River. Wyoming as Project Manager of Texas Gulf Black's Fork Trona Development. In 1971 he joined Allied Chemical Green River Works, as Resident Manager. In 1972 he joined Energy Development Company, an Iowa Public Service Company Subsidiary, as General Manager of their Coal Development. He currently is Senior Vice President and General Manager of Energy Development Company, and serves on their Board of Directors as well as the Boards of several other subsidiaries. This past April he was elected to Iowa Public Service Company's Board of Directors. Ed, his lovely wife Pat and children live in Hanna, Wyoming. He has been a member of the RMCMI since 1973. Is a staunch supporter of his community and the mining industry.

Jan 1, 1981

By H. Petersen

If a coal mine producing two hundred thousand (200,000) tons of coal per year could effect a 2 per cent decrease in the percentage of slack there would be an additional 4,000 tons of prepared coal produced. Most operators will say that these prepared sizes of coal are worth about $3.00 more per ton to them than the slack or in other words an additional $12,000.00 pier year profit could be made by a decrease of 2 per cent in slack. A large tipple with all the finest modern equipment of shaker screens, conveyors, box car loaders, etc., can only produce a grade of coal dependent upon the coal delivered by the mine car at the top of the tipple. In the mine, coal-cutting machines have been doing their part for many years toward decreasing the percentage of slack. There is therefore, only one phase of production left where real effective work can be done, that is, intelligent and constant supervision of preparatory work and shooting. The quality of coal is really entirely dependent upon the kind of coal produced at the face in the mine. Our problem is therefore, at that place. The writer is thoroughly convinced that with the proper placing of holes the use of correct amount of a suitable explosive, thoroughly tamped, with the bug dust entirely removed from the mining, a decrease in slack can be effected. We will take up this problem under five headings. First-The proper placing of bore holes. Second-The proper amount of permissible powder. Third-The proper loading and stemming of the shot.-Cushing shooting. Fourth-The necessity of removing the bug dust from the mining. Fifth - The - standardization of rounds. First-The Proper Placing of Bore Holes. The most important thing and the real secret of successful blasting of coal is the proper placing of the bore hole. This results in the correct balancing of the shot and the securing of the maximum efficiency of the explo¬sive. If you are operating a mine with a 6-foot coal seam, you most likely are using a 6-foot cutter bar on the coal cutting machines. You should use three holes to properly bring down the coal. (1) A center shot in the middle of the room drilled flat, or rather parallel to the mining-the heights of this hole will depend upon the top parting. If the coal is frozen to the roof, it will be necessary to have the hole as close to the roof as possible. If there is a free parting, the hole may be placed lower but not over twelve inches from the roof. (2)

Jan 1, 1925

Presiding: Herman Van Houten, Senior Marketing Counselor, Joy Mfg. Company, Pittsburgh, Pa., and John A. Reeves, Vice President, Mid-Continent Coal &Coke Co., Carbondale, Colorado. The Keynote Speaker, Senator Jennings Randolph from West Virginia, was unable to come due to pressing business in Washington. A film presentation on Surface Mining and Reclamation, "Energy Bridge," Courtesy of Pittsburgh & Midway Coal Mining Company, Denver, Colorado, was shown and was prefaced by comments from James V. Fisher. "Advantages of Longwall Mining in Western Coal Production" was a paper presented by David W. Wisecarver, Supervisory Mining Engineer, U.S. Bureau of Mines, Denver, Colorado. Mr. Wisecarver graduated from Virginia Polytechnic Institute in 1949. After two years with International Harvester and two years in the U.S. Army, he joined the engineering staff on a Bureau of Mines underground mining operation in Virginia for eight years where he saw duties as mine surveyor, shift boss, and assistant maintenance superintendent.

Jan 1, 1977