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By Parley Potter

GENTLEMEN OF THE COAL MINTING INSTITUTE: I was requested to write an article on mining a short time ago; however, the time has been so short that I have not had time to prepare an article as I would like to have presented it to this body. In writing this article it has not been my intention in making comparison of various mines, to favor one or discredit the other. I hope it will be considered in that light. The coal mining industry as I have seen it in the past, at present and in the future. In years gone by large tracts of coal land could be obtained at a very small cost, and as yet coal land may be purchased at a reasonable price in this country, but I believe the time is near at hand when the methods of mining will have to be changed greatly in this country. Many changes have taken place-in the last few years, some of them have been forced by law, others by the coal operators themselves, after being convinced that the changes made were for their own benefit. During my 20 years in the mines I have seen thousands and thousands of tons of coal lost that could have been saved if proper methods of mining had been used. The Room and Pillar system of mining coal is none. too good at its best ; a certain per cent of the coal is always lost, yet it is about the only system that can be used under certain conditions, but where the Longwall system can be used I believe it is the best system yet introduced. If the Longwall system is used' there is no coal lost. You get it all as you advance with the workings. Some coal operators object to the Longwall system for several reasons, and most of the reasons they advance are not founded on facts. For instance some of them claim it is too expensive. I will admit that the cost per ton is a little higher in Longwall than it is in Room and Pillar as a rule for the amount of coal' mined, but after the Room and Pillar mine is finished as a rule there are thousands of tons of good coal lost, for the simple reason that it cannot be mined at a profit. In many cases if the same mine had been operated on the Longwall system every ton of saleable coal could have been mined at a fair profit, and in the long run would have netted the owner much more money than it did under the Room and Pillar system. The Longwall system has been in operation many years in Europe and especially Great Britain, and is the most approved of systems in many countries at the present time. Millions of tons of coal have been saved by its use in those countries. It is claimed that the Armour Packing Company loses nothing but the squeal of the hog when it is killed, and doesn't allow it to squeal much. Why lose coal if the Longwall system of mining will save it? The Longwall mine is far more easy to ventilate than the Room and Pillar mine; the air has a much less distance to travel for the same amount of working face in Longwall than it has in the Room and Pillar.

Jan 1, 1921

By Hugh McLeod

To make the statement that coal mine operation has been entirely revolutionized within the last ten years is a mild statement. This has been entirely due, of course, to the almost universal introduction of mechanical loading in coal mines. Under the old system of contract loading too much was left to the individual miner's judgment and willingness to do the right thing. Each miner regarded the place in which he worked as "his place," and depending upon the judgment and ability of the miner, conditions as found in these places largely reflected that man's individuality or personality. Many men kept their places well timbered and in such condition that they were not only able to load their turn but were able to take advantage of any surplus cars that might be available in their particular entry. These men were often regarded as "coal hogs." However, these men's places were usually found to be well timbered and well maintained. Supervision under this old system in a strict sense of the word amounted to casual visits to the man's working place by the foreman or his assistant once each day as required by law.

Jan 1, 1938

James Westfield, Assistant Director, United States Bureau of Mines, Washing- ton, D. C., called the second morning session of the Rocky Mountain Coal Mining Institute to order, and promptly introduced John Peperakis, Manager of the Sunnyside Operations, Kaiser Steel Corporation. Sunnyside, Utah, who spoke on "Ground Control Developments, Sunnyside Mines, Kaiser Steel Corporation." Mr. Peperakis illustrated his talk with a number of slides which were not reproduced with the printed text. (For the printed text of Mr. Peperakis' paper see index.) James J. Diamanti, President of the Car- bon Fuel Company, Helper, Utah, was introduced by Mr. Westfield, and he spoke on "Small Mine Operators Help Themselves." Questions from the floor followed Mr. Diamanti's talk.

Jan 1, 1961

By F. T. Baker

The Primero mine, operated by the Colorado Fuel & Iron Company, is located 17 miles west of Trinidad, Colorado, in Las Animas County. Unusually bad roof conditions, along with heavy side pressure and other conditions causing rapid decay of timbers, all combine to create a very serious timbering problem. The height of the coal averages six feet six inches. It is a heavy coking coal and has a tendency to become easily crushed and broken down in the seam. The seam lies about 35 feet below the sandstone and the intervening formation is composed of loose shaly rock, and as the coal is extracted, the air slackens this rock to such an extent that within 24 hours, roof falls varying from five to fifteen feet in height are likely to occur. Under these conditions it is necessary to use cross bar sets in both rooms and entries, and they must be spaced no further apart than three and one-half foot centers, and be maintained within a distance of three feet of the face. Rooms are spaced on fifty footcenters, and cannot with safety be driven to exceed 14 feet in width, and 200 feet in length. The large pillar must be maintained to protect from side pressure, and the rooms must be driven up and retreated with as quickly as possible to avoid the squeeze caused by the intense side and roof pressure. Best results in extraction have been obtained by driving rooms for only a distance of 150 feet. Under these circumstances, it is readily seen that timbers of small diameters cannot be utilized in timbering any development work of a permanent nature. Entries are driven nine feet wide, and special peeled piling with an average diameter of 12 inches are most commonly used. It, is necessary to use lagging between each set of crossbars . Conditions such as these necessitated an immense expenditure for mine timber. In addition to ordinary seven and eight foot props, we used a yearly average of 65,000 feet of heavy peeled piling, averaging in diameter from 10 inches to 12 inches. Annual expenditures for timber of all classes was in excess of $60,000.00. Timber costs per ton averaged around 29 cents. In view of these exceptionally severe timber conditions at Primero, the company, in 1920, had a survey made with a view of providing some remedy to this problem. A comparison of the life of main entry timber at other bituminous mines was made, and an average life of four years was established. The actual data collected at Primero indicated an average of less than two years in the manway or "return" airways, and up to five years on the haulageways or "intake" airways. While some of this timber will stand up for a much longer period than this, a close inspection will reveal in most cases that its period of usefulness is spent. It is very essential when discussing the life of timber, especially that used on, main haulageways and aircourses, that a distinction be made between the point of service, that is, the point where it is sound, serviceable and able to carry weight, and the point of breakdown or failure, where it is no longer sound and able to carry weight. In figuring the life of timber, the point of service only should be considered as timber will frequently stand for a considerable length of time when it is entirely decayed and unserviceable. The larger part of the timber used for our permanent work was Alpine Fir, or what is locally termed Red Spruce, and the supply of this I is gradually becoming depleted and has to be obtained at a point so distant

Jan 1, 1926

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 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

Briefly, the machine consists of a steel frame mounted on roller bearing wheels and axles, an electric motor, a fully enclosed speed reduction gear unit, a specially designed centrifugal pump driven through a friction clutch and silent chain, a mixture tank and agitators, and all necessary operating and control mechanism. The wheels are mounted on solid roller bearings made of special roller bearing steel, and are cast with deep chilled threads. The axles are of high carbon axle steel. A General Electric Company motor, of special design to exclude dirt and moisture, is used. It has an unusual overload capacity and a maximum torque at starting speed. Special arrangement can be also made for storage battery operation. The motor drives from one end, through a flexible coupling, to the speed reduction unit, and from the opposite end, through a similar coupling, to the pump clutch. The design of the flexible couplings is such that the drive is reversible. The speed reduction gears are enclosed in an oil and dust proof housing. All spur gears, as well as the main drive clutch, are made of steel forgings, with accurately cut teeth. An aluminum bronze worm wheel and special heat treated alloy steel worm provide the speed reduction for the traction drive. The worm shaft is mounted on Hyatt roller bearings and the thrust is taken in each direction by ball thrust bearings. The main drive shafts are of special alloy steel and operate in Hyatt roller bearings. The slow speed shafts run in extra large bronze bushings. Ample and constant lubrication is provided by splash from the gears running in oil. The Mudite pump is of special de- sign. A renewable wearing plate protects the pump casing from the natural wear of the mixture. The open runner is mounted on an extra large shaft which runs in a Hyatt roller bearing on the pump end and in Timken roller bearings on the outboard end. A special cage prevents water and grit from reaching the pump bearing. All thrust from the runner is taken on the Tim- ken bearings and these bearings also provide for the accurate and easy adjustment of the runner. The pump is driven by a silent chain, which operates on cut steel sprockets, from a friction clutch. The clutch is designed to secure long wearing qualities with minimum attention and its adjustment is easily effected. It is mounted on Hyatt roller bearings and the clutch drive shaft also runs in the same type of bearings. The pump discharges through a nozzle, which is adjustable, and controlled by the operator. The mixture tank is of approximately 650 gallons capacity. It is provided with a mixing well constructed of perforated plate screen to prevent large hard particles from getting into the valve or pump. The tank is filled through an opening in the top directly into the mixing well. On a shaft running longitudinally through the tank are arms so arranged that the mixture is thoroughly mixed and kept in continuous circulation from end to end. This shaft is driven from the speed reduction unit by a steel roller chain operating on cut sprockets. The traction drive is taken from the worm wheel shaft through steel roller chains of extra large size that run on cut steel split sprockets on both axles. An idler sprocket provides for easy chain adjustment. The axles are mounted in solid roller bearings in fully-enclosed dust proof housings, which support the frame through coil springs. These springs eliminate twisting strains on the frame on account of track irregularities and also relieve the working mechanism from road shocks. The speed reduction from the motor to the wheels is such that it gives an operating speed of approximately ninety to one hundred thirty feet per minute. The brakes are of the conventional shoe type and engage the wheels on both axles. They are operated by a hand wheel conveniently located and

Jan 1, 1925

By R. Dawson Hall

R. DAWSON HALL (The Coal Age, New York City) : Mr. Chairman and gentlemen: I do not feel that I have anything in particular to say. I have not prepared anything for an occasion such as this. I just came from New York City, and as one man said to me today, "That is not any recommendation in particular." (Laughter.) In answer to your request for a few remarks of a timely character I would say: One of the possibilities in the Rocky Mountain Region coal mines is the use of steel arches, posts and straps. The timber of the region seems unusually subject to dry rot and does not last long, especially in those places as in southern Wyoming, where the mine atmosphere is likely to contain a large quantity of carbon dioxide. It is true that, in many mines, much care is taken to drive out this gas and to arrange that the timber will have the fresh air that will prolong its life, but despite such provision much timber is subjected to speedy rot. Steel has made rapid progress in England, Germany and France and is recognized as an economy, not an extravagance. Frequent replacement of rotting wood and removal of broken rock are a source of great waste, risk and inconvenience in operation that together spell great cost. The very dryness of the mines and the lack' of acid water are favorable to the use of steel where support of roof or sides is necessary.

Jan 1, 1932

By P. F. Patterson

It is a well established fact that 60 per cent of all accidents in coal mines occur from falls of roof and coal at or in the proximity of the working face. Notwithstanding that this is well known, and has been frequently discussed by mining men, this seems to be the irreducible minimum. It is even said by those in a position to know that the percentage stated is increasing. With this, information before us it would seem that not enough attention is being given to close supervision at the working face, and until this is done we may expect to continue experiencing an increase in the accidents in this area. No workman generally feels that it is more important to finish loading a car of coal than to set a timber for protection, and many accidents happen from this source, not from a lack of knowledge of the dangerous conditions existing, but negligence in taking remedies necessary to remove the danger. It is true that nearly all state laws require the mine foreman or his assistant to visit each working face every day, but with the constantly changing conditions on account of the advance of the working faces, these daily visits may be entirely inadequate to discover possible dangers and prevent accidents. The obvious remedy then is closer and more systematic inspection and supervision of the working faces. Many accidents are caused in mines on account of not enough clearance between the rib and track or between timber and track. On all main haulage ways. there should be a space of at least 30 inches between the rib and track, or timber and track, and on all rooms not less than two feet should be left between the track and upright timbers.. A great deal has been said and written with regard to systematic timbering. We doubt very much the feasibility of adopting any standard of timbering that would be suitable for all roof conditions, and any such system in our opinion would not tend to cause a decrease in the number of accidents. The proper place to put up a prop, regardless of whether it conforms to any established system, is under a piece of loose roof. No habit is becoming more prevalent among miners and other mine workers than wearing gloves, principally flimsy canvas gloves, which afford no protection to the wearers and are the direct cause of many hand injuries. If gloves must be worn, and no doubt they will be as the habit has become well established, then they should be made from some heavy material and should fit the hands fairly snug.

Jan 1, 1923

PRESIDENT PRYDE: I am sure we have all listened with interest to the presentation of this subject. Anything that promises economy in coal mining today is welcomed by all of us. We will now have a discussion on this paper. If any of you gentlemen want to ask any questions, you may do so. I think we will develop something of interest and along the lines of economy. That is the first consideration of a coal mining man. MR. H. D. RANDALL: It is an interesting fact that in manufacturing we find the greatest economy results from giving a man the simplest possible act to perform, while there is nothing too complicated for a machine. If we want to put up a set screw we find it cheaper to let one man set it up and the other screw it in. The maximum economy is what we are after. Similarly, one of the points of greatest interest which Mr. Ickis has emphasized, is that this automatic equipment not merely dispenses with a manual operator, but also performs certain functions which the operator cannot do. It provides an inherent protection to the apparatus and service not possible under manual operation. We very rarely have cases of failure with these automatic equipments, .and consequently have the advantage not only of having eliminated the operator's salary, but also his mistakes. We have had a large number of these equipments in use for several years, so that their practicality is now thoroughly proven, and the trend of practice now indicates that the automatic idea will be further extended and will become universal for such classes of service. MR. D. C. McKEEHAN (Union Pacific Coal Company) : My notion of an automatic sub-station is one that does not necessarily require new equipment beyond the control equipment; so that any of you that are interested in it can take up with the manufacturers and find out how much it would cost to change any equipment. The greatest point I think is the fact it eliminates the several nationalities from operating the set, either on day shift or night shift. They can so lock the control as to make it impossible for anyone to start or stop it, except the one who has the authority. Another point I do not believe was brought out very clearly: It would be particularly advantageous to people who buy power, and if you could have several sets in parallel, it would allow you to start the shift with one set and cut in the additional sets as the shift progresses. There are various operations that stop at the end of each shift, and-one or two or three sets can be cut out, leaving the load on one set, providing the size of the copper is sufficient to supply all the points of the mine. Another point I want to bring out: In case you have quite a number of sets distributed along transmission line, the switch trips, the operation restores the service, and you may have several hundred-or in case with us, we would have several thousand-K. V. A. of Motor Generator Sets and Rotaries, that would be starting at once, and the switch would automatically trip out again. MR. RANDALL: Another form of control was described as the so-called supervisory control. This control could be started up so the starting would not be synchronous, but could be spread out over a sequence. MR. McKEEHAN: I think that is rather a theoretical consideration for coal miners. They are standing at the controller ready to shut it off unless there is some selective method of starting various sets- MR. RANDALL: I had in mind this supervisory control, one man, a central operator who would determine which station should start and he would take time enough to have his load come on gradually. He would not permit all the installations to come on simultaneously, but come on in succession: MR. McKEEHAN: You misunderstand me. Suppose we had the main switch at Rock Springs, which supplies several camps, and there are several

Jan 1, 1924

MR. TESCHER (Disaster at Dawson) : I move that you appoint a committee of nine members of this Institute to draft a set of resolutions that we can send out to all members of this Institute, to the mine officials in all four states, that might go towards preventing these disasters; that we reach all men, all mining men, mine officials of all kinds. I think we have enough brains to carry out a few suggestions of that kind. I think you are fully familiar or know men who are fully qualified to act on this committee. The only qualification that I have is to ask that Mr. Harrington be appointed a member of this committee. PRESIDENT WHITESIDE: You have heard the motion, and I believe it was seconded. Is there any discussion? That is a subject that really needs a great deal of thought. MR. LAMB: Things like that can't be handled in a minute. What Mr. Tescher suggested is all right, but to my mind, going into a great many of these different properties, seeing the conditions, such things hit pretty close to home. I would suggest that you put this off; lay it over until such time as the people who had the disaster have some time to think these things over. It is too soon to offer even a suggestion. Suggestions are all right, but there are no nine living men in the United States who can stand up or sit down and talk it over and give you any reasonable answer, in one hour or six months. First, you would naturally have to go down there and converse with the men who were at the camp at the time. You are all operators; all you operators would -like to talk it over today. You realize that anything that is good for the camp is always acceptable in disasters of this kind. I say, do it gracefully and not by publication. MR. TESCHER: I feel that the men present know these suggestions by heart and they don't have to discuss them. They know them instinctively and they know they will apply to any mine. It must be understood that if these suggestions are not carried out, they ought to be; and there is a motion before the house. PRESIDENT WHITESIDE: Mr. Murphy, you started to rise to your feet a moment ago. Have you anything to say on the subject? MR. MURPHY: I have just returned from a visit to Mr. Brennan. Mr. Brennan and I have worked together for twenty years. The manager of our company asked me to go down there and express his sympathy. Those things come to all men if they live long enough, in the coal business, and he wanted me to express to Mr. Brennan personally his sympathy and deep regret. What I had in mind when I started to rise, was to suggest that the Institute as a whole express its sympathy to Mr. Brennan. I don't think there is a man in Utah, Wyoming, Colorado or New Mexico who has done more in safety' lines than Mr. Brennan, and it just seems bad luck that he had this disaster, and I am in hearty sympathy with the gentleman who spoke about not appointing this committee. I believe a resolution to Mr. Brennan would be very much better. JAMES DALRYMPLE: I am in sympathy with this gentleman here. I think it is going to hurt the feelings of those connected with the mines in which this disaster occurred. If you will give me the privilege for a few minutes, I will gladly express myself and the action that has been taken in the past by this Institute, and my opinion combined with a great many other opinions. And what I am going to say is going to be said by the-well, I am going to say it as I see it. I am going to say it not in an unfriendly spirit, but from a spirit of not undue criticism. I happen to be one of the original members who organized this Institute. I did what I could to obtain memberships. I remember very well when we had our first meeting that we had a very large membership. I think I have a photograph of the members which was taken on the steps of the Capitol building at that time. Our membership at that time was composed largely of underground officials. I mean by "underground" officials, the superintendents to some extent, the mine foremen, their assistants,

Jan 1, 1923

By Eugene McAuliffe

The subject of my few remarks addressed to the Rocky Mountain Coal Mining Institute, "Guessing or Knowing! Which," may perhaps suggest but little to you here today. However, I am sure you will all agree with me when I say that in the conduct of a coal mining operation there should be no choice between guessing and knowing. The value of, and the results to be obtained from this Institute, its meetings and printed transactions, as well as those of other similar educational organizations, depend very largely on the mental attitude of those who constitute, through their pronouncements, the more active portion of the membership. Perhaps the most apt criticism that is now being made of the coal industry is that, to an extent possibly exceeding any other industry of similar magnitude and importance, it depends for its conduct altogether too much on "rule of thumb" and "tradition," rather than on proven practice and actual fact. The records of our coal mining association meetings bear expression of many conflicting opinions, the majority of which are sincerely put forth by those expressing same as representing the facts; the extremes expressed, however, frequently fix the question raised as one yet located in "no man's land." There are yet too many chances taken we are still "weighing pounds on railroad track scales" and measuring yards with the proverbial "bit of string." The actual expense of conducting any one of the several operations incident to the production of coal is rarely determined, and in many instances the general cost figures, prepared some weeks after the work is complete, are of that sweeping character that very little can be abstracted therefrom. Many coal companies are now making a daily cost sheet, showing the cost of labor and material in detail, as used in the several related operations,, and such is decidedly helpful, particularly to the mine superintendent and his foreman, who, without such, sail an uncharted sea; the auditor's belated monthly summary rarely ever seen by these men who are held responsible for the labor and material used. I have made reference to this situation as an accentuation of the fact that the coal industry contains more "serious minded, conscientious guessers" than does any other similar industry, although the annual cost of our product runs up well beyond the billion dollar mark, and what is more important, our industry is one that still continues to exact a heavy toll of human life. Now this brings me to the question of safety, the one question that should be, and which is, I know, uppermost in your minds. The coal mining world, engineering and operating, is now well sold on at least two things the theory of using permissible explosives and the elimination of the open light. Furthermore, the industry, particularly that portion which is located in Great Britain and the United States and Canada, are now planning vast extensions of the use of "rock" or "shale dust," both in the form of "dust barriers" and in "direct application" to entries and cross-cuts. This is well; however,, my study of past mine explosions has convinced me that the great majority of such had their very beginning in gas accumulations; frequently originating in restricted areas at the working face, in abandoned worked-out areas, or in some other certain place where ventilation is not, maintained as it should be; and that again leads me to the point where it can again be well said, that there is too much "rule of thumb," too much guessing now being done in regard to the volume of air required, and continuously furnished, in a given entry,, panel, room or area. Just to emphasize this situation, is it not a fact that the majority of mine inspectors express the ventilation conditions as measured by them, in terms of cubic feet per man employed, in each certain split, and does not the mining laws of many states yet demand a minimum of "100 or 150 cubic feet

Jan 1, 1924

PRESIDENT LITTLEJOHN: The paper of Mr. Emrick will now be open for discussion for about twenty minutes. The meeting is now open for discussion. MR. EMRICK: There is some question that may have occurred to you at different times, that is how are you going to tell when the bits are properly made? A fairly good rule to go by is when the used bits come out of the mine, if half of them are bent and half of them are broken, the average is pretty good MR. GEO. B. PRYDE (Union Pacific Coal Company): I would like to ask Mr. Emrick if he has any figures as to the saving of Dower with the different styles of its. MR. EMRICK: I suppose you mean chisel point bits and pick point bits? MR. PRYDE: Yes. MR. EMRICK: So far as I have been able to learn, the only reason why chisel point bits are used is to prevent coring that might be done by the cutter chain. The pick point bit, of course, is the proper thing to use. It can be used when the position of the cutter links in the cutter chain is right. I do not know of any figures which give power consumption ratings on the use of pick point and chisel point bits, but there are tests and ratings, etc., which have been taken- which have been tested as against different bits, which have been given proper clearances against bits not having been given proper clearances, and they will run,-in their saving in power, they will run 20 to 25 per cent. MR. A. C. WATTS (Chief Engineer, Utah Fuel Company) : I would like to ask Mr. Emrick if he has any record showing the saving in power on using the alloy steel chisel bits. I know that several experiments have been made; I do not recall the figures now, but we had a very decided saving in power. MR. EMRICK: I haven't any of the records. Do you think that is because of the steel that has been used? MR. WATTS: Well, they were all sharpened by the same man and used in the same machine, and at the same shop. I do not know the composition. It is "Red Star" Vanadium that I had in mind. MR. EMRICK: I have not seen any records. Some companies are using the tool steel bits because they stand up a little bit better. MR. BENEDICT SHUBART (Secretary) : I was going to ask Mr. Emrick about that question. There is one company that does not recommend tempering the bits. They recommend using not exactly self-hardening steel, but one that is bard enough without quenching-they use 80-90-point car- bon but about a 70-point manganese, not exactly self-hardening steel, but they do not temper this at all. Will Mr. Emrick state if a steel of that kind could be worked in the bit sharpening machine that his company makes, as it

Jan 1, 1925

Jan 1, 1968

Jan 1, 1976

Jan 1, 1979

By George B. Pryde

Dear Sir: Yours of July 23rd, relative to my appointment on the Safety Committee in connection with the Rocky Mountain Coal Mining Institute. As you say in your letter, "The duty of this committee is to draft suggestions as to safer mining practices with the idea of preventing disasters in coal mines." Much has been written and many suggestions made on this same subject, and it is very hard to put up further recommendations than have already been made. The disasters you mention in your letter unquestionably have direct reference to coal mine explosions, which from time to time still occur in this and other countries. As far as our Western mines are concerned, you know that sprinkling and shot firing by electricity have been very extensively carried out. Notwithstanding these precautions; we have had a few rather serious disasters in the past in these mines. I do not care to place any blame or responsibility on the companies having these disasters, but it is a fact that in each and all of them, after careful investigation has been made, that the human element has had more or less bearing on the accidents happening. From most reports that we gain, either directly or indirectly, it is very evident that investigation shows after an explosion that the rules governing one or both of the above safety measures have been somewhat carelessly or negligently carried out. Much has been written and read about rock dust sprinkling, but it is questionable if this method is doing a great deal toward the eliminating of disasters. While it is true it may have the effect of preventing propagation, still I do not believe anyone claims for it a sure preventative against initial explosions. I had occasion not long ago to visit a mine, after an explosion, in which dust barriers were supposed to be hung, and from indications it was quite evident that the dust barriers had been in operation, but they did not prevent the explosion from reaching all open parts of the mine. It is also true that profuse scattering of rock dust throughout a mine would have a beneficial effect, but there is a question arises here as to whether the sprinkling by rock dust or the spraying by water, if available, is the most effective. I am satisfied that if all coal mines are kept well sprinkled and all open workings maintained in a thorough moist condition, that the biggest factor in a coal mine explosion is in this way eliminated. There is no doubt but what the use of permissible powder, particularly if shot by electricity, has had a very marked effect on the number of disasters in mines, and if this method of shooting was energetically carried out there would be a difference in the number of explosions, both minor and Major, all over the country. Some of the recent explosions have taken place where no shooting was being done, but there is no denying the fact that the other ingredient, namely, coal dust, entered in the elements very extensively. We have read and heard of hydraulic cartridges and other patents (substitutes for powder) that were being worked out for the purpose of

Jan 1, 1923

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Jan 1, 2000

Jan 1, 1978

MR. DICKINSON: There is an increase of dust in machine loading, especially with the McKinlay loading and cutting machine which was extremely dusty. MR. FORRESTER: Declared more dust must be expected because when loading by machinery, the coal is shot harder in order to make it easier for the machine to pick it up. He believes however, that there was less hazard because of the closer supervision possible by reason of the concentration of operation. MR. McAULIFFE: Machine loading more dusty than hand loading. D. HARRINGTON: The hazard is greatly increased by modern methods of loading. Not only do the methods increase the quantity of dust, but they also increase the rapidity of mining and the increased quantity of coal broken down causes large quantities of gas to be released. The number of motors on loading machines and conveyors add to the hazard. No more dangerous places can be found for such motors than at the working face where there is excessive quantities of pure coal dust and where there is more gas than along any other point. Regarding Mr. Herres remarks that the machine loading was safer on account of the concentration and possibility of close supervision, Mr. Harrington said he believed concentration likely to prove a source of danger rather than its preventive. At Dolomite, Alabama, a number of men had assembled, and as a result what was a relatively small explosion killed a large number of men. Concentration is not without its dangers to mine operations. MR. McAULIFFE: These arguments do not appeal to me. Few places are better sprinkled than the working places in a machine loading mine. There is. more effective supervision, and there can be more ventilation. I believe machine loading will increase safety by that very concentration that Mr. Harrington deplores.

Jan 1, 1925