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Jan 1, 2004

Past President, A. Z. Dimitroff, Supervising Mining Health and Safety Engineer, Health and Safety, District H., U. S. Bureau of Mines, Denver, Colorado, opened the Fifty-eighth Annual Meeting of the Rocky Mountain Coal Mining Institute at the Hotel Colorado in Glenwood Springs, Colorado, at 10:30 a.m. His introduction of President Charles M. "Dock" Schloss follows: It is indeed a pleasure to call the meeting to order and to welcome you to this, the 58th regular meeting of the Institute. This morning I have the pleasant assignment of presenting to you a person who has been so active in the Institute, and has worked so closely with many of you, that I am sure most of you have known him much longer than I have.

Jan 1, 1962

Jan 1, 1926

By C. E. Drennan

Your Chairman and the Program Committee have limited the time allotted to me, and so, with your permission, I will omit the preliminaries, and wade right into my subject. I believe I am safe in taking for granted that you are all agreed that electricity is the most feasible means of transmitting the power used in coal mining. If you are not, then the papers read before the Association in previous years have failed of their object. If you are so convinced, the only question is as to the choice between alternating and direct current, and the voltage. Fundamentally, this is primarily a matter of dollars and cents. With the sole exception of your trolley locomotives, there is no part of your equipment that cannot be operated as well on alternating as on direct current. With your pay rolls at their present high level and the efficiency of the labor you employ at the stage it now occupies, I believe you will agree, first, that everything possible must be done to increase the tons of coal produced per man employed; and, second, that ample power at all times must be available at every machine so that every one of your men can really get out a day's work without any avoidable delay. Speaking Electrically, all this means is a machine instead of a man wherever it is possible for a machine to do a man's work, and full voltage at the machine always, so that there can be no excuse for the work not being done promptly and efficiently-and dependably. The real reason for the selection of one kind of current or the other can best be understood by considering the formula which determines the size of wire required for transmitting electrical energy. The size of the copper required, and, consequently; its weight and cost, depends upon four factors: 1. The amount of energy or power to be transmitted. 2. The distance to be covered. 3. The percentage of loss allowed. 4. The voltage at the receiving end of the line. These factors enter into the problem to different extents, and, briefly, the size of wire depends directly upon the amount of power and the distance transmitted, and inversely upon the percentage of loss allowed and the square of the voltage. From this it will be seen that, with the amount of power and the distance fixed, if the loss is to be cut in two, the wire must be doubled with a given voltage, while if the loss remains constant and the voltage is doubled, the wire may be cut in four; that is, reduced 75 per cent in weight and cost. Now, standard motors are designed and recommended by their builders to run within a range of 10 per cent under voltage to 10 per cent above voltage - 440-volt motor, then, should preferably not be operated on less than 400 volts

Jan 1, 1923

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

Jan 1, 1925

By Scott Dupont

Due to the scarcity of miners, and the necessity of decreasing the cost of mining, the Phelps-Dodge Corporation, Stag Canon Branch, at Dawson, [ ] New Mexico, decided to try, by various methods of mining, to increase the tonnage of coal mined per man, per day. With this in view, they first tried mining on a 250-foot face, maintaining the track at the face and using six to eight men shovel- [ ] ling. These men were able to aver age from ten to twelve tons each per, day when they were loading, but with

Jan 1, 1926

Mr. Geo. B. Pryde, Chairman; Committee on Safety, Rocky Mountain Coal Mining Institute, Rock Springs, Wyoming. Dear Mr. Pryde: In accordance with suggestion in your letter to me of June 21, 1923, Mr. Roberts, Mr. Dalrymple and I had a meeting and attached find our contribution to the proposed August report of the Committee on Safety. You will note that we have confined ourselves to matters in connection with explosions and prevention of explosions, in coal mines. If the committee is to report on general safety in coal mines, including accidents from haulage, timbering, rock falls, electricity, etc., we would like to suggest that you ask other members of the committee to specialize on one or more of these subjects. Especially we believe it would be advisable to specialize as to precautions against electrical accidents with giving of data as to maximum voltage, precautions to be taken as to gas ignitions by mining machines at faces, best methods of placing power wires underground, etc.; also give information as to up-to-date safety installations, such as whistle devices notifying of disarrangement of ventilation or devices for quick cutting off of electrical power from mines under certain conditions; also give data as to efficient safety man cars on various pitches, etc. Yours truly, D. HARRINGTON.

Jan 1, 1923

PRESIDENT LITTLEJOHN: Until Mr. Wood comes back, we have a gentleman with us who has been sitting in one of the back seats. He has never gotten up and showed himself, and I think we ought to call on Mr. Ryan to stand up and say two words, or a half dozen words. Mr. Ryan! (Applause.)

Jan 1, 1925

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

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

By D. C. McClure

MR. McCLURE: Mr. Chairman, you sprang a surprise on me; I really came over here for a good time. Gentlemen, I am not at all qualified to pose as an expert on pulverized fuel; I have merely been making some rather interesting observations, and unfortunately at the present time, a great deal of substantial data, the technical data, I don't happen to have with me; it is still in the process of being calculated, but I will be very glad to tell you some of the observations as I have made them, and in as truthful and complete a way as I can. The question of how we would handle fuel became a very pressing subject in this new Valmont electric plant, which is now under progress. We have studied the methods of burning fuel for a number of years on different types of stokers at the existing plants in Denver; we are burning it with a natural draft chain grate and with underfeed and with forced draft chain grates, and I am very frank to confess at the present time that I have no answer as far as stokers are concerned for a better solution of the problem of burning lignite. In other words, I could not tell you that this or that is a better type of stoker to use for that coal. However, to boil the thing down, after considerable trials, the underfed stoker was chosen as the one most adaptable for the utilizing of lignite fuel if stokers are to be used. In other words, the chain grate was put aside. I might say in support of the chain grate, the prime reason for which that type of stoker was condemned, as far as lignite goes, is the initial investment charge and the large maintenance which is involved.

Jan 1, 1923

The 78th Regular Meeting of the Rocky Mountain Coal Mining Institute (hereafter referred to as RMCMI) convened at the Marriott's Mark Conference Center, Lionshead Village in Vail, Colorado. The meeting was called to order at 8:45 a.m. by the President, Ira E. McKeever, Jr., who is President, Western Mining Operations, Natural Resources Group, W. R. Grace & Co. McKeever was introduced by Past President Edward F. Ziolkowski, Senior Vice President and General Manager, Energy Development Company in Hanna, Wyoming. MR. ZIOLKOWSKI: The first order of business this morning is to introduce the president and for a business meeting as well as other items on the program. It is my pleasure to introduce Ira McKeever to you this morning. Ira was born and raised in Kit Carson, Colorado, and served in the U.S. Navy prior to obtaining his geological engineering degree in 1952 from Colorado School of Mines in Golden. He then spent the next 20 years involved in mining sulphur, pot ash and coal with Texas Gulf Sulphur at that time and Gulf Resources Chemical Corporation. In 1972 he joined W. R. Grace & Co. as president of the Mining Division, Natural Resources Group. He was named Colowyo Coal Company's president and general manager in 1976 to develop what is currently Colorado's largest coal surface mining operation. Last year he became W. R. Grace's president of Western Mining Operations which is the position he presently holds. Ira is active in civic affairs; he is currently serving on the Colorado Energy Impact Assistance Advisory Committee. He is a member of the Colorado's Metropolitan Water Roundtable, he is also a director of Project Colorado, a member of the committee for the Colorado Division of Commerce and Industry. He has, in the past, served as chair- man of the Craig Hospital Board. In 1967 Ira was the recipient of the Colorado School of Mines van Diest Gold Medal Award, and in 1981 was given the individual service award for outstanding accomplishments in the field of health, promotion, physical fitness by Colorado's Governor's Council for the Health and Promotion of Physical Fitness. Memberships are also held in Denver Coal Club, the Colorado Mining Association, and the American Mining Congress. Will you please welcome Ira McKeever? I do have one other piece of business here. If you will all join with me, yesterday was Ira's birthday. I asked what year that was, but I couldn't get that out. So, I'm not going to lead the singing. Someone is going to lead the singing. But I think it would be appropriate if we did sing happy birthday this morning and I think it would also wake us up. How's that? All right, will you join me please? (A chorus of the Happy Birthday song followed.) President McKeever's address: MR. McKEEVER: The secret is that I'm double nickles. So I've got a few more years hopefully to be with you and this wonderful industry that we represent. Thank you Ed. I realize now more than ever, the tremendous effort that you put in the program last year and the magnitude of the job that is placed in the presidency of the Institute. It was indeed with tremulous hands that I undertook to lead the Institute this year, and I found a tremendous amount of strength and guidance in my friend Ed whom we've known since college days and worked together. On behalf of that lifetime of memories and good thoughts, Ed, I would like to present to you a little token of appreciation. 1 would like to join Ed in welcoming you all to Vail. Ed arranged the weather, 1 arranged the program along with Charlie Margolf. This is the 70th regular meeting of the Rocky Mountain Coal Mining Institute; and in accepting the leadership a year ago, 1 obligated one very special person to fill the role of chairlady and hostess for this meeting. I would like to have you all, if you haven't already, meet my wife, Linda. I would like to thank her publicly for her guidance and help she continues to provide me. It's absolutely necessary that you also meet and recognize Charlie Margolf our program chairman who will be helping through the meeting to present and monitor our program; and anyone who knows Charlie knows the sincerity and dedication he brings to anything or any phase of life he touches. We will be seeing him in action this afternoon when he chairs the most interesting panel presentations. Don't miss it if you can help it. A couple of logistical comments. We will have to keep our meeting on schedule so that any of our non-agenda items that we need to keep, maybe we

Jan 1, 1982

CHAIR: I see a great many safety men in the audience and I hope you will all take part in using up the time that we have left. The point brought up by all was the necessity of education. It is very hard to know just how this is going to be done. We get very little encouragement to do this. At a recent meeting at Rock Springs, 100 in attendance, and most of them mine officials. Another condition which contributes to accidents is the labor turnover in many of our States. With many companies I am told from actual statistics the labor turnover is 125 per cent. Each field has different mining conditions so that men coming from one field are not always familiar with the mine conditions in the field they come to. These are conditions which have to be overcome. WM. LITTLEJOHN: Mr. Harrington brought up the subject of sprinkling. I will try to tell what we are doing at the Utah Fuel Company camps. Our dust at Castle Gate is the most inflammable gas that has yet been tested at the Pittsburgh station of the Bureau of Mines, so it is up to us to use every precaution to keep it down. I will try to tell what we are doing regarding sprinkling from tanks. We now have in operation two tanks in our locomotive roads, one in Castle Gate, one in Sunnyside. These tanks are something like 500-gallon tanks with pump on one end of truck which gets its power from the power wire and has a half circle perforated pipe on the other end of tank. This is simply hooked on to the locomotive. When the pump is started up it throws a fine spray of water all around which wets the roof, the sides and floor. We found this very successful from an economical as well as a working standpoint. A roadway that we probably would have had to pay a man at least two shifts for, covering the full distance, with the ordinary hose and spray, we can do in half a day and do it more thoroughly. We are also figuring on at the present time using the same system on rope haulage ways, which of course will have to be run by a reel from the feed lines, handling say four hundred feet each way before reconnecting. We haven't got it finished, but are working on it at the present time. MR. COLBURN: I would like to say a few words -about this question of education. Education was mentioned by all three sections of the Safety Committee. Education regarding safety might be divided into two branches. One branch is for the official at the mine to keep him acquainted with the latest developments in safety equipment and safety methods. The other part of education is for the workmen. The United States Bureau of Mines is co-operating in both directions. Safety Clubs are organized around the Bureau of Mines First Aid Training, but it is the idea to expand those clubs and teach the miner the advantage of such-things as the closed safety lamp, and also the regulations that have been made for his safety. In Illinois we can't operate with the closed lamp, because the miners in that section of the country are not educated to the advantages of the safety lamp. Another form of education has been taken up by the National Safety Council, consisting of voluntary organizations similar to the Institute, to which all mining men are invited to attend. Such conferences nave been held in the Lake Superior district, in Butte, and in Globe, Arizona, this year. These are to be extended throughout the coal mining regions. CHAIRMAN PRYDE: The Union Pacific Coal Company has also built two tank cars of 600 gallons capacity each. The tanks are connected with hose, so that water can flow from one tank to the other. A centrifugal pump is mounted on a truck, and connected to the front tank. This pump takes its power from the trolley wire. The discharge from the pump is perforated, so that it sprays the floor and sides of the entries. We expect to use this water train on main haulage ways where we have no sprinkling line.

Jan 1, 1923

Jan 1, 1951

By C. A. Allen

When the writers were asked to prepare a paper on this subject for this meeting of the Institute there was some question in our minds as to what to say that would be of interest to the members. You all know that Utah has some wonderful seams of good coal, on which have been opened some of the most modern mines in the United States, and that her coal operators have been putting forth many efforts to reduce losses due to accidents as well as disease. While I believe that the physical condition of Utah's mines is as good as in any other state we are not unaware of the fact that a great deal can still be done and we are always willing to frankly discuss the accident situation in the state. Dr. Murray has assembled some interesting figures showing the monetary loss due to accidents and disease which I will will proceed to give you to show the necessity of continued efforts in welfare work regardless of humane considerations.

Jan 1, 1922

The 64th Regular Meeting of the Rocky Mountain Coal Mining Institute convened at Jackson Lake Lodge, Grand Teton National Park, Wyoming, and was in session at 10:00 a.m. The meeting was called to order by Past President .Tames Westfield. He introduced Mr. Raymond C. Lillie, President of Grand Teton Lodge Company, who welcomed the members to Jackson Lake Lodge. Mr. Lillie stated he had been with the organization since the Lodge was built. They had a snowstorm the day before our meeting so stated it was perfect weather for coal miners. Mr. Westfield introduced President Joe T. Taylor, Superintendent, York Canyon Mine, Kaiser Steel Corporation, Raton, New Mexico. Mr. Taylor was born in Miami, Florida. Attended the Colorado School of Mines and graduated in 1952. He was associated with Sunnyside Operations of Kaiser Steel Corporation in Utah until 1962. Was then transferred to the Koehler Mine in Raton, New Mexico, as Superintendent, and had charge of opening the new mine, York Canyon, and at the present time is in charge of Kaiser operations there.

Jan 1, 1968

CHAIRMAN LITTLEJOHN: Some of the members will want to question Mr. Farnham on some of the things he has brought tip, so we will throw the meeting open for discussion. I am quite sure Mr. Farnham will be willing and glad to answer any questions that may be put to him. MR. HOLMAN: I would like to ask Mr. Farnham a question in regard to the Duckbill: How wide a face will it operate without moving the bill? MR. FARNHAM: The Duckbill is a device that was developed in the Union Pacific Mine at Rock Springs, within the last few months, and it is shaped something like, a dustpan, with discharge throat in the rear. They made one seven feet wide and found it was too wide, and the one they are using now is between three and four feet in width. The front section of the conveyor, which attaches to the duckbill, meshes into it to form a sliding section, and the front end of the Duckbill is pushed by the upper segments. I saw one used in a room twenty-four feet wide, and they drew it back after they cleaned out one room and pushed it forward again. MR. HOLMAN: You have no arrangement other than ratchet work? MR. FARNHAM: The ratchet is for forward working and back; the sections are made 12 or 13 feet long, and the stroke of the conveyor automatically works the ratchet; they can ratchet it back; it is a hand device. MR. HOLMAN: They just swing the end of the conveyor across the face to pick up the loose coal? MR. FARNHAM: Yes; they are also planning to use it endwise along the panel face, that and the room work both are quite new in their application, and I do not think the Union Pacific is giving out any results as yet, because the system has not been in use long. MR. HOLMAN: We are planning on putting one in very shortly. MR. HALL: I understand they can swing it over 30 degrees one way or the other, and it goes the same way easily because of the continual jar of the back and forward motion on a 60-degree swing. SECRETARY SHUBART: Take on a comparatively long conveyor, you can get quite a sweep, a large part of the circle. The Duckbill could command quite a large range. For a 12-foot entry, take a four-foot wide advance through the middle of the shot coal, with a 12-foot advance, ratchet back, swing the Duckbill to the rib and repeat; but I do not think they could get as much as 60 degree. on the end of the Duckbill without curving further back. The conveyor is light and not normally set on any permanent foundation. I saw one of Mr. McCarty's first machines, a rather rudimentary one, clean tip a 12-trot entry, 21 tons of coal, in 16 minutes, three men at the face and one at the loading end. MR. FARNHAM: The average time to clean the entries is about an hour-to clean up good-it wouldn't take but a short time; that is why they get this record of several cuts a shift. CHAIRMAN LITTLEJOHN: Are there any other questions you would like to ask Mr. Farnham? MR. HOLMAN: We were discussing this entry driving in regard to the entry loader; an entry loader in advance work, just what you have to do to place the jackbars with the sheave-blocks? Do you dig along the ribs after the coal is shot or do you have any other scheme that could be worked out to a good advantage? MR. FARNHAM: This record is a report I have just received from our Chicago office, without the full details, which I have written for. I am sorry I cannot give you the details. This was an Indiana or Pennsylvania mine, near Pocahontas, not the one where they had an accident. I assume they set the jacks ahead and swung and dumped the coal partly out with a scoop and partly by hand, but the application for that for entry driving is entirely new. The reports stated that they anticipated using that as a standard method of entry driving in the future. I will be glad to see that you get a copy of it when I get the report completed. MR. MONAY: Mr. Shubart, did you say they loaded 12 tons in 16 minutes? SECRETARY SHUBART: Twenty-one tons. MR. MONAY: How long did it take to change the machinery out of there

Jan 1, 1926

By R. A. McAllister

The haulage system employed to convey coal from the face to the outside, dates back to 300 B. C., when slaves carried the mineral from the face to the consumer. The British discovered coal on their island about 800 A. D. and they were the first people to make practical use of coal and make coal mining a successful operation. The Britons carried cargoes of coal in their trading expeditions long before Columbus discovered America. The early history of mine haulage in the British mines relates to women with baskets, a practice still in use in Korean mines. Coal was discovered in America in 1679. The first mine worked in the United States was opened at Richmond, Va., in 1770. The haulage inside consisted of a crude sled loaded with, sacked coal ready for the market and drawn by a mule. The tipple consisted of the very simple operation of loading the sacked coal to the back of a lame mule, which represented the transportation system between mine and boat. The capacity of the boat was one ton and this large production of coal was intrusted to a small boy, who delivered to any place in town his bushel basket filled' with winter fuel. One daring coal operator shipped fifteen tons of coal by boat to Philadelphia and the man in charge had to seek employment to pay his board while finding customers for his fuel. A production of five tons per day would hardly attract attention to any system of haulage, add three ciphers and the importance of mine haulage is made very plain to the management. I will consider a production between 3000 and 5000 tons in eight hours and endeavor to bring out the essential features necessary to make the haulage system a regulated precise factor. There are two phases to mine haulage, the mule trip from the room to the motor or gathering party and the main haul to the outside. The motive power, whether done by mule, wire-rope or electric motor cannot be effective if left to the power alone. Conditions must offer no obstacle and it is the removal of obstacles that make the haulage system. This paper will consider a flat seam with the usual jump ups and downs or natural obstacles to be met and mastered by the successful tail-rope or electric system. The pit car is no longer a screening system scattering the fine coal from the room to the outside, adding to the costs by giving employment to road cleaners and polluting the ventilating system with a fog of coal dust. It is not a contrivance with four flat wheels and a labor killer in the room or on the tipple The large producing mine has a pit car with a tight body, roller-bearing wheels, with a self-oiling system that offers the least possible draw-bar pull to overcome the friction resistance, a hand brake conveniently placed and positive in action, a wheel base short enough to make room necks and long enough to

Jan 1, 1921

By NA N/A

Jan 1, 1931