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By Lewis C. Karrick

Although the Bureau of Mines has thus far made no large-scale experiments with oil shales, and the feasibility of the commercial manufacture of shale-oil products suited to present market requirements has not been demonstrated, there is ample reason to believe that these products will eventually supplement the more commonly used petroleum products and give equally good service. In 1919 the bureau, in cooperation with the Department of Metallurgical Research, University of Utah, began investigating the oil shales of the United States to obtain detailed information on their value. The States of Colorado and Indiana also cooperated through their State universities, in which research laboratories were organized to assist in carrying on the oil-shale studies planned and directed by the bureau. As a result of these studies much information is now available concerning laboratory methods of producing the greatest yields of the best products from oil shale. In order to study the principles that govern the retorting of oil shales and to test the oils produced, it has been necessary to develop and standardize reliable apparatus and methods for distilling shale, and to adapt to the testing of shale oils some of the methods the Bureau of Mines uses for testing petroleum. The methods employed by the Scottish shale-oil manufacturers were also studied, but most of them have been superseded by those described in this bulletin, which give more comprehensive and accurate results and employ more convenient apparatus. This paper is presented, therefore, as a manual of apparatus and methods that the bureau has developed for work on oil shale and found satisfactory for routine tests and for research. Explanation and discussion of the principles underlying the methods of testing are included wherever necessary for a clearer understanding.

Jan 1, 1926

By W. L. Goodwin

Twenty-five years ago mining engineering in Canada was not a profession. To-day the members of the mining fraternity can fairly claim for 10themselves the professional status. If their pretension is not fully warranted by fact it is not for lack of any technical attainment or service to the public but by reason merely of their neglect to cultivate the cohesion and consciousness that are the outward and visible signs of a professional body. This paper is an attempt, first to sketch briefly the course of the events during the past thirty-five years that have resulted in organizing the mining industry of this country in its present form; then to notice the principal features of the professional organization of this day; and finally to point out that an important part of the work of the mining engineer remains in the state of chaos that characterized the whole of it three or four decades ago, and to suggest a remedy. Thirty years ago there came a great wave of interest in mining in Canada, based principally upon the discovery of gold-quartz and gold-copper throughout wide areas in Nova Scotia, Ontario and British Columbia.

Jan 1, 1926

By Bennett R. Bates

Nowhere in the world has cone classification in closed-circuit grinding with tube mills reached as high a state of development as on the Wit-watersrand. In the development of the Far East section the necessity of fine grinding to obtain satisfactory residues gave rise to a situation with which the cone could cope only at a great sacrifice in efficiency of tube-mill grinding. H. A. White1 recognized the limitation of the cone in his study of the theory of tube milling as early as 1915, but it was not until Ewing, Davis and Willey2 carried out their tests at Springs Mines during 1920 that the advantages of mechanical classifiers were demonstrated. During the fall of 1924 the writer supervised a series of tests with Dorr classifiers undertaken by Mr. White, Consulting Metallurgist, at the mill of the Geduld Proprietary Mines, Ltd., Dersley, Transvaal (Far East Rand). The importance of classification to obtain efficient tube-mill grinding was thoroughly demonstrated. The installation of classifiers of the above type that followed the test confirmed the results of the experimental work. Tests with Cones, Straight Type and Bowl Classifiers The test at the Geduld mill was made to determine the relative grinding efficiency of a tube mill when grinding in closed circuit with cones, straight type Dorr classifier and Dorr bowl classifier. The efficiency of a tube mill, as expressed in this article, is based on the tons of minus 200-mesh material produced by the mill. The efficiency is also expressed in terms of tons of minus 90-mesh material produced by the mills to correspond to the standard practice on the Witwatersrand. The results given for the performance of the tube mills grinding in closed circuit with cones (Fig. 1) were taken from previous tests carried

Jan 1, 1926

By C. H. Trik

Any article or discussion on the ventilation of Working Faces under different systems of concentrated mining is of little value to any practical man unless based upon facts gleaned from actual experience, and empirical data on this subject is, to say the least mighty scarce. Of this one thing, however, you can rest assured, the old cry of "no air at the working faces" will have become a thing of the past. No longer will we hear of some operator who has been too eager to get out the coal and who has lost sight of everything else in his mad dash for production, digging himself shut until his airways are mere pin- points and his air current a feeble thing, too weak to combat the high resistance of his restricted mine. A mine operating under one or more of the various systems of concentrated mining should always have plenty of air, for in concentrated mining the tendency is toward greatly reduced mine resistances due to increased sectional areas. It can readily be seen that the tendency is to large, wide areas across the panel and where this is true large volumes and low gauges are the rule, unless inordinate restriction is encountered in the permanent airways, and no operator, far sighted or progressive enough to adopt this system of mining when his conditions permit, would ever allow his main airways both intake and return, to be anything but model courses. As a matter of .fact, we are likely to encounter the opposite of what is usually the case in most mines to day. We are apt to find the air at the working faces sluggish due to the large areas of passage rather than to high resistance. This is combated in. various ways which will be discussed further along in this article. Those companies, of which we have knowledge in this country who, to- day are using any of the new systems of mining, seem to proceed alike in the general method of developing their acreage. Let us assume, for this discussion, the Utah Colorado Coal Corporation is going to open a mine under the new system and their conditions are such as to permit their adopting the simple block system, each face served by a separate machine, each entry having its conveyor to the cars. After the permanent haulage and airways are driven "narrow work" starts to shape the blocks. We are not interested in the length of these "conveyor headings" since we do not need to drive breakthroughs nor build stoppings for ventilation until we have reached their end when we connect them together. We have two methods of sending air to the face of these dead ends. We can laboriously and expeilsively install brattice cloth, as we go, or we can use a small auxiliary blower with canvas tubing to the face. Indeed I may say that one of the great difficulties encountered under the new systems is in the ventilation of these narrow faces. After they have been connected and an air circuit or current established, ventilation becomes plain sailing until the block is worked out. The auxiliary blower when used with flexible canvas tubing, has been found to be the ideal answer to the question of how to ventilate the headings which are anywhere from 100 to 1,000 feet long. These small blowers when properly used, can go a very long way to assist in further reducing the cost of production already assured by the new method of mining. Right angle bends are made by the tubing manufacturers to enable the fan to sit in the fresh air current, yet out of the way of operations and any recirculation is positively avoided by blowing the air around the corner to the face.

Jan 1, 1926

By R. S. McCaffrey

In addition to its importance in agricultural production, Wisconsin is a very large manufacturing state and its rank in the metal working industries is probably first among the States of the Union per unit of population. The University of Wisconsin is a state supported institution and the Wisconsin tradition has always emphasized the relation of the University to the state and its responsibility to exercise its leader-ship where it might, in any and every way, for the development and benefit of the state and the community. The Department of Metallurgy of the University realized its responsibilities in the carrying out of the co-operative tradition and, two' years ago, an experiment was started in co-operative research between the University and certain of the industrial plants of the state. At the present time this work has so far progressed that it is no longer an experiment, and its results prove that this co-operative research may be carried on very advantageously and that, under the conditions existing in the state, the method employed has been satisfactory.

Jan 1, 1926

By John B. Phillips

The mine is entered by a central vertical shaft, strongly timbered, and containing two compartments-one for the passenger cage, the other for the large skips bringing the ore to the surface. A man-way, for emergencies, is also provided, parallel to the shaft. The cage is a single-deck steel box, carrying about thirty persons; by means of arrangements above and below, it can also hoist and lower materials needed in the workings. Levels are run at intervals of 100 feet. In special cases, where the ore conditions warrant, sub-levels are operated, such as those at 1,113 feet and 1,123 feet (Fig. 7), which are connected by winzes with the 11 th level. One of these was pushed for 40 feet, and then abandoned because it was unprofitable to take up ore of the grade encountered. The ore between levels is removed by stoping. The drifts follow the course of the veins as much as possible, with numerous cross-cuts. Winzes, raises, connections, etc., are blasted out where needed. The main drifts are at least 8 ft. high by about 9 ft. wide. All former narrow drifts had to be widened some time ago, by ruling of the Ontario Department of Mines, to lessen the danger of accidents with cars in the small passages. Accurate plans of the under-ground workings are kept in the office, and extensive surveying is always being done underground to keep the maps up to date, measure the cubical contents of stopes, and so forth. Timber is extensively used in the construction of supports and chutes, and in the sinking of the shaft. Steel and concrete are too ex pensive to compete with timber, which 1s abundant in such sections as have escaped forest tires.

Jan 1, 1926

By Carl Pierce

The writer of this article has not attempted to write a technical paper; on the contrary, he has tried to express in "steel-plant English," for steel men, a viewpoint drawn from his practice and experience. It is not his thought that it shall be taken as the "last word" in the making of this class of steel, or that good rimming steel cannot be made by any other practice. The paper was written to serve as the basis of a discussion from which it is hoped much benefit may be derived. The paper deals only with rimming steel made by the open-hearth process, and with the lower carbon steels, such as sheet and tin bar, rivet stock, skelp, etc., although good rimming steel as high as 40 to 50 carbon can be made by having good open slags and giving proper attention to working and tapping temperatures. Definition of Rimmed Steel Rimmed steel is sometimes called open or effervescing steel to differentiate it from killed or partly killed steel. It is steel made by a process which permits the free escape of gases from the metal in the molds. In passing up through the metal, the gases keep it in a rolling action from the walls of the mold inward. The top of the ingot rims in as the metal chills and the walls of the ingot get thicker, the center part remaining fluid until it reaches a pasty condition when it is covered with a cast-iron cap. The Charge In making up a charge for rimming steel, clean stock of a known composition must be selected, special attention being given to the analysis of the materials. The silicon in good rimming steel must be eliminated to a trace, therefore it is advisable to have a uniform amount going into the charge. Too much silicon gives a raw melting heat from which rimming steel is unlikely to result. For this reason a charge containing not to exceed 40 per cent. pig iron and 60 per cent. scrap, with no iron ore, is preferred to the Monell type of charge in which as high as 65 to 70 per cent. pig iron is used with a proportional amount of iron ore for the removal of the excess silicon and carbon. The silicon content of pig iron varies so much from day to day in the average blast-furnace practice that there is danger of getting too much of this element in the latter mixture when

Jan 1, 1926

By J. A. Orr

The details connected with the mining and subsequent handling of Creighton ore were fully covered in a paper presented to the Institute in 1920. The following brief notes describe certain phases of the present practice and show wherein it differs from the practice at that time. These may be summarized under the following headings. (a) Recovery of pillars. (b) Drawing the ore. (c) Change from sub-level tramming to branch-raise system. (d) Chute construction. The present stoping practice is the same as formerly, i.e., fiat-backed shrinkage stopes of 60-foot width, between rib pillars of 15-foot width, extending from the footwall to the hanging-wall. Formerly, when these stopes were completed to the stopes above, they were drawn empty of broken ore, and the 15-foot rib pillars were caved into the stopes and drawn off through the same chutes as were used to draw the ore from the stopes.

Jan 1, 1926

THE manufacture of Portland cement on a commercial basis dates back to the year 1824, when Joseph Aspidin, of Leeds, patented his process. It was, however, only within the past 25 years that the cement of to-day commenced its history, and during that period manufacturers have constantly tried to improve the grade of cement.The introduction of the rotary kiln at the opening of this century was the starting point of rapid development in the process of manufacture, and in the quality of the cement produced.Following on the rotary innovation came the wet process. This at first was used only where the raw materials were of a soft nature; but to-day nearly all classes of materials can be treated by this method. Oompared with the dry process, it allows for greater refinement of raw materials, more intimate mixing, better chemical combination, and economy in fuel. Taking advantage of this, the manufacturers in England and America are in a number of cases substituting the wet for the dry process.Subsidiary machinery throughout the factories, such as crushing and grinding mills, have also been vastly improved. The chemists, too, have done their share in the work. Long and careful research has proved the necessity for accurate proportioning of raw materials, thorough mixing, and very careful burning. All these factors combined have given us the product of to-day, which is consistent within very narrow limits, and far superior to that of the beginning of this cement era.

Jan 1, 1926

By Marc Piard

In a cool mine, tapping high-pressure lines through reducing valves lowers the temperature beyond remedy. It is the writer's suggestion that, for low-pressure work, law-pressure air ,should be generated in a compressor installed underground adjacent to the work, and that the jacket-water of the compressor should be utilised for re-heating purposes. Such a system of compressed air distribution, designed especially for service in cool mines, is described in the following notes. The suggested system includes a three-wire pole line from the sub-station to the opening nearest to the working face, with a cable connection extending to the latter from the openings; an electrical centrifugal unit; a reservoir excavated in the ground; and a distribution line, re-heated by jacket-water. As regards the reservoir, it may be pointed out that in many mines there are blind or abandoned tunnels that could be used for the purpose. The centrifugal type of compressed air machine is a comparatively new departure, and it was formerly considered that such a machine, operating at less than 1,000 kilowatts per unit, would be commercially impracticable. At the present time, however, these machines are being built in Europe for as little as 400 kilowatts per unit, and as much as 110 lb. per sq. inch pressure. One advantage which these centrifugal machines have over other types is that they may be driven by plain induction motors, without the help of special starters-a consideration of the first importance where the electrical regulations are severe.

Jan 1, 1926

By C. G. McLachlan

INTRODUCTION The work described in the following paper was under-taken with a view to determining, if possible, the relative importance of some of the phenomena on which flotation seems to depend, in the hope that, if this information could be obtained, it would be of value in dealing with the problem as a whole. At the outset, brief reference will be made to three papers which had a considerable bearing on the course followed in the present investigation. In 1919, Langmuir, in a paper on 'The Mechanism of the Surface Phenomena of Flotation', showed that mono-molecular films of very great stability could be produced on solid surfaces with oleic acid, but that pure paraffin oil, though spreading readily on a dean dry surface, was easily displaced by water.

Jan 1, 1926

By George W. Bain

The area in Quebec immediately north of the Ottawa river is underlain by a large area of granite gneiss intruded in lit-par-lit fashion into Grenville sediments and low silica intrusives of the Buckingham Series. This complex of metamorphic rocks is intruded by a much later magma found, chiefly, as a very large stock about 20 miles in diameter and extending from Brownsburg to Grenville, and as dykes and small outliers at various places adjacent to its outer margin. 1A similar stock at Rigaud, Quebec, is situated south of the Ottawa river and has been described by O. E. Le Roy. The earliest representatives of the later magma are a series of granodiorite dykes characterized by abundant hornblende, along with primary magnetite and subordinate sulphides scattered as roundish grains through anorthoclase and aligoclase feldspars and subordinate quartz. The rock is found as narrow dykes and shows no prominent secondary structures, either in the field or in thin sections under the microscope.

Jan 1, 1926

By H. A. Bedworth, W. H. Bassett

The amount of oxygen present in refined copper bears an important relation to the effects of various impurities on physical properties of copper, as well as the effects of reducing gases at higher temperatures. It seems fitting at this time, when the effects of reducing gases on copper are being discussed, to describe methods that have proved satisfactory for the determination of oxygen and sulfur, and to present some results obtained by investigation of these methods in the authors' laboratory. The procedure for the determination of sulfur is closely interrelated with that for oxygen and has, therefore, been included. It was first proposed by Hampe1 that oxides in copper could be accurately determined by the loss in weight sustained by finely divided copper when reduced at red heat in pure hydrogen, or by the weight of water produced. Hampe's method was later modified by Archbutt,2 who established the accuracy of the method and demonstrated that equally accurate results were obtained by noting the loss in weight or by weighing the water formed. The determination of oxygen by heating in carbon monoxide has been proposed by West.3 In our hands this method has given slightly lower results than obtained by heating in hydrogen. Heath4 found that the loss in weight after heating in hydrogen did not represent the true oxygen as cuprous oxide but included also gases derived by the metal from the fuel and refining in the furnace, and any trace of mechanically held moisture. He found, further, that the copper after ignition retained hydrogen equivalent to about 0.01 per cent. Heath proposed to determine the amount of occluded gases by preliminary ignition for 20 min. in pure carbon dioxide—and to correct the error caused by absorbed hydrogen by subsequent ignition and cooling in carbon dioxide, finally replacing this gas with air.

Jan 1, 1926

it may be clearly seen that one of the most rapidly increasing items in mining operations is the cost of the timber alone, to say nothing of the cost of installation. Consequently, any practical means that may be used to lengthen the life of mine timber will greatly tend to decrease mining costs and result in important economies in operation. The four principal agents by which mine timbers are destroyed are, decay, insect attack, fire and mechanical abrasion. Decay and insect attack are credited with more than 50 per cent of the total amount of timber destroyed in the mines. Numerous methods may be used to conserve mine timbers, such as better selection, preparation, storage and segregation. It frequently happens that good timber goes into places where poor timber would do as well, and timber of inferior quality is sent into places where only the best grade should be used. However, the most effective method of conservation is by treatment with some standard preservative to prevent decay. Some of. the benefits to be noted from the use of preserved timbers are; the reduction in operating costs by decrease in timber purchases; cuts down interference with mining operations due to timber failures on main haulageways; prevents excessive falling of roof in entries by maintaining timber in sound condition; conserves timber supplies and makes possible the utilization of inferior woods; reduces the danger of mine accidents; improves mine ventilation; lessens fire hazard. Our experience thus far with preservatives, while not of a sufficient period of time to establish just what length of life we may obtain from timber so treated, results obtained during the past four years indicate that the intelligent use of preservatives will effect sufficient economies in mine timber costs to justify the expenditures made for this purpose. MR. BAKER (Concluding): Now, if there are any questions you gentlemen would like to ask about our particular operations, I will attempt to answer them. J. H. EMRICK (Sullivan Machinery Company, Denver, Colo.) ; I was wondering how much penetration you get. MR. BAKER: We get between one-sixteenth and one-eighth of an inch; it is a dipping process. With pressure treatment you get-a greater absorption; that is, better than one-sixteenth of an inch. As long as there is no mechanical abrasion, it seems to serve the purpose. MR. EMRICK: Does that apply to the condition of the timber before it is treated? If it is perfectly dry, will it absorb more treatment than if it is partly green? MR. BAKER: Certainly; one of the things we do is to have it thoroughly seasoned before it is put into the preservative. We put some green timber into the mine once, and the fungus went after it right away. MR. EMRICK: What was the difference in the depth reached by the preservative? MR. BAKER: It hardly penetrated at all when it was green. It has to be sound and well seasoned. MR. EMRICK: How long was the timber dipped or treated? MR. BAKER: According to the seasoning. If it was well seasoned, it was left in the hot bath for an hour; if not so well seasoned, it was left for about a couple of hours. C. M. BILLINGTON (General Superintendent, Rocky Mountain Fuel Company, Lafayette, Colo.): Have you found it necessary to treat timber that has been charred? MR. BAKER: No. However, I suppose it has the sane effect; in lots of places they char timber for the purpose of treatment. MR. BILLINGTON: Have you ever tried lime and salt? MR. BAKER: No, this is the only thing we have tried, the creosote and the Aczol; the Aczol is a foreign product. WM. LITTLEJOHN: Which I is preferable, the Aczol or the creosote? MR. BAKER: I couldn't say as to that. MR. LITTLEJOHN: Have you had any tests as to the value of either? MR. BAKER: We have had some of the Aczol timbers in service for a little over four years; we have had some creosote timbers in service

Jan 1, 1926

By J. W. Sanger

The establishment of a central steam-heating system in Winnipeg and its inauguration in October, 1924, has attracted a considerable amount of attention. Not only does it excite the curiosity of the engineer, but it has stirred financial and civic bodies throughout Canada to such a degree that there is now a much keener general interest in this particular type of public utility than has been shown heretofore. This does not mean that we may expect a mushroom growth of central-heating systems in all our larger Canadian cities in the near future, but it does mean that the pioneer work which Winnipeg is now doing will undoubtedly be used to guide others in their judgment as to the feasibility of similar projects elsewhere. The success of the municipal hydro-electric system in Winnipeg, and the low rates for electricity resulting therefrom, was without a doubt the most important factor influencing the citizens of Winnipeg to venture into this new field. The events which led up to the central steam-heating proposal in Winnipeg are interesting.

Jan 1, 1926

At the meeting of the American Institute of Mining and Metallurgical Engineers, G. S. Rice, Chief Mining Engineer of the U. S. Bureau of Mines, announced the definition of a gassy mine. This definition has been awaited with much interest, especially by the Safety Committee of the Rocky Mountain Coal Mining Institute. It applies to the whole area of all mines, any part of which is on the public domain of the United States. Consequently it will be of wide application in the western part of this country. The safety committee of the R. M. C. M. I. has been hopeful that the Institute would adopt this definition without exception as the codes of rules to be recommended at all mines in the Rocky Mountain area. The statement follows: "The U. S. Bureau of Mines believes that all coal mines are potentially gassy; but for purposes of administration in respect to prevention of explosions and fires, the Bureau recommends the following classification: "Class 1 coal mine-A practically non-gassy mine in which flammable gas in excess of 0.05 per cent cannot be found by systematic search. "Class 2. coal mine-A slightly gassy mine in which (a) flammable gas has been found, ? but in quantity less than two per cent in still air in any active or unsealed-abandoned workings; or (b) flammable gas can be found, but in quantity less than four per cent, in some place from which the ventilating current has been shut off for a period of one hour; or (c) flammable gas can be found,* but in quantity less than one-fourth per cent in a split** of the ventilating current; or (d) flamamble gas is found in quantity greater than' specified rate*** of not more than 25 cu. ft. per minute. "Class 3 coal mine- A gassy mine in which flammable gas is found in quantity greater than specified for a Class 22 coal mine. GENERAL NOTES REGARDING DECISION NO. 3 "(A) Flammable gas found in coal mines is, with rare exceptions, methane. In coal-mining fields where natural gas is found in lower geologic horizons by deep wells which pass through or nearby the coal mines, there have been rare instances of la leakage from the well. Natural gas is chiefly methane; that constituent almost always forms more than 85 per cent of the whole, but it usually contains ethane, propane and traces of butane also. Therefore if the latter gases are found in mine air it is an indication of leakage. The lower limit of explosibility of methane-air mixture when there is turbulence of five per cent and of natural-gas-air mixtures with about ten per cent ethane and associated hydro-carbon gases is 4.6 per cent. The limit therefore varies with the character of the mixture. " (B) To determine the proper classification of a coal mine, it is advisable that systematic testing and sampling be done at least three times in a period of not less than 72 hours. All tests and samples of the mine air, except one, must show an inflammable-gas content less than the maximum limit of the class to which the mine is assigned. In other words, a tolerance of one test or analysis may be permitted to provide for a mistake or a very exceptional occurrence. "(C) When a new mine is being opened in a coal field where existing mines are generally gassy, it is common sense to assume that similar conditions will be found in the new mine, and its development and equipment should be based upon the expectation that it will be assigned to Class 3."

Jan 1, 1926

By L. D. Tracy

"The first study of this subject has been made in Illinois, but as opportunity affords, similar studies will be made in other States. It is hoped that the data obtained will assist the coal—mining industry to standardise the forms of leases, and so avoid some of the abstruse and ambiguous clauses which may be found in many of then and the consequent liability of costly litigation.In some of the publications of the Illinois Mining Investigations prepared under a cooperative agreement with the U. S. Bureau of Mines, the Illinois State Geological Survey and the Engineering Experiment Station of the University of Illinois, the coal areas of the State have been dividedinto eight geological districts, each district being treated separately.report covers District No. VI of that classification, and it is hopedstudies of the other districts will be completed in the near future and similar results published.The report includes a short description of the geological condition the character and quality of the coal and the nature of the surface, data for which have been taken largely from the Illinois Geological Survey publications.Mining methods and percentages of recovery are mentioned, together physisal conditions, market and transportation facilities, because all of these factors have a bearing on royalties and leasing conditions."

Jan 1, 1926

By L. D. Tracy

This is the third of the series of reports on coal-mine royalties and leasing conditions in Illinois. The results of the study of District VI were published as Serial No. 2726, January, 1926, and those of District VIII as Serial No. 2745, April, 1926, of the Bureau of mines. The counties of Macoupin, Sangamon, and Montgomery, which are three of the principal coal-producing areas in the northern part of District VII, have been chosen for this report because these counties cover an entirely different part of the State than do the two districts already covered. Some leases in, Randolph and Washington counties are included as they are in the southern part of the district, and the data happened to be readily available.

Jan 1, 1926

PRESIDENT MOSES: Mr. Hall, can you tell us something that will help our cause? R. DAWSON HALL: I did not want to tell anything; I wanted rather to say something, if. I said anything at all, about my impressions regarding the safety of the mines in the West. We heard yesterday how terribly dangerous they were, and I think that is due to the natural conditions. It is interesting to note that many of the developments of safety, which you will find all through the country, had their origin here in the Rocky Mountain States. It has not been because the Rocky Mountain States have been negligent - though, of course, they could have been more active - but it is becaues the conditions have been such as to make accidents more numerous. Rock dusting by mechanical means was used here before any other country adopted it, let alone the United States. It is true that rock dusting was started in England; but it was by hand, as it remained with the Victor -American Fuel Company to be the first to distribute rock dust by machines, and that is to the credit of Mr. Murray, who was the man that did the original dusting in those mines. It was at Delagua, they put up shelving and put dust on it; they used the adobe, and Mr. Pryde, at Reliance, very early in the game, put dust in the Reliance Mines, and some of the dust, I believe, is there yet but they can hardly find it for the new dust. That is not all. I believe it was first in the Utah Fuel Company's mine that incombustible clay was used for stemming, and in the East, where we were in the habit of using slack entirely, that was a big advantage. Another thing that the West has originated has been the wetting of the chain in cutting. The people in Alabama took a great deal of credit for having used that very early, but not as early as Mr. Brennan did at the Hanna Mine, he having used water on the cutter bits in 1913. Another development was that the Phelps Dodge Corporation were the first people to use, I believe in the United States, storage battery locomotives for main haulage, and while they didn't go ahead with that, so far as putting in power trucks and mining machines, until just recently-I think the Consolidation Coal Company in the East managed to get ahead of them in that development,-notwith-standing, they were the earliest to use it for main haulage. When I came through this section of the country, in 1912, I think it was, I went through the mines of the Union Pacific Coal Company. I was surprised to see the extent to which fire-proofing had been carried out in that mine, with regard to non-combustible brattices and overcasts, which were of concrete; even the boxes were covered with sheet metal. They were very far ahad of us in that respect; far, far ahead of us in the East, because the East has its favorable conditions in the fact that most of the lump in the mines is more or less wet all the time. Another safety provision which has been taken by the Utah Fuel Company, was shooting from the surface. That has not spread very much in the, East, but it has been used in Oklahoma and the middle West. I think there is plenty of evidence that the Western people have been thinking for themselves, in going ahead and' establishing new standards in Safety. One of the most unusual things is this Safety Committee, permanent Safety Committee of the Rocky Mountain Coal Mining Institute, which has been endeavoring here to find out the conditions under which safety cant best be practiced. I think it is those who venture to. criticize the West that) have to show that in the East there is not the spirit which has led the Rocky Mountain region to endeavor to reduce its very terrible death rate that really exists. It has to be faced and it furnishes a cause, an incentive; for further work toward safety; but none can deny that the desire of the western mining man has been to find

Jan 1, 1926

By Stewart, J. B.

THE property at which this work was done consists of a large deposit of potash salts occurring in massive beds of rock salt, overlain by 600 ft. of salt-impregnated shales and marls. It is in the Province of Cataluiia, Spain, about 45 miles from the railway station of Mauresa and about a mile south of Suria. In addition to sinking the shaft, the program of construction work laid out by the European owners (not Spaniards) included a single-track narrow-gage railroad from Mauresa to the mine; one large office building and several large shop buildings, all of brick and concrete with steel truss roofs; two extensive benches for the future recovery plant; and a large village of stone dwellings for employees. The pay-roll showed approximately 1200 to 1500 men employed. After two years' operation, ending early in the autumn of 1920, the shaft had been sunk 325 ft. and still had an equal distance to go to reach the potash; all tunnels for the railroad were done and the road-bed $0 per cent completed; only a little more than the foundations were completed for all the large buildings, and the excavations of the benches were about 75 per cent done-while only a fair start had been made upon the employees' village. This was the state of affairs when the European owners decided to offer this property under a one-year option to an American syndicate, providing that they agreed to carry on the entire building program and to sink the shaft as fast as was consistent with the quality of work which they demanded, for they wished the shaft to endure at least 200 years.

Jan 1, 1926