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By K. L. Marshall

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

Jan 1, 1924

I have sketches of the radiators, and on this sketch up in here (indicating) we show the line from the fan-exhaust steam from the fan, and the trip spray at the mouth of the mine, which is usually near the tipple, the set of radiators on each side of the entry, exhaust steam exhausting in by the radiators, the small atomizers which I mentioned, and the man sprinkling at the hose. There are times, when at different times we have a man sprinkling during the day time, when he is out of the way, and during the night, sprinkling on the motor roads. I will leave that print up here and let you look at it and if you have any questions you wish answered, Mr. McAllister and myself will be glad to answer them. (Applause.) PRESIDENT PRYDE: . I am going to ask Mr. Hair to leave the sketch on the wall. From the back part of the hall, it is hard to see what is there. The figures are very important. I think one member of this association will be glad to know the cost of water, Friend Littlejohn. MR. LITTLEJOHN: I don't know as I want to ask any questions. The only thing I' would say about the cost there, it is very close to that cost that we tabulated for the Utah Fuel Company at the Utah mines here some time ago. We have not tabulated lately. It may be a little over that at the present time if you take the. labor costs and the material. costs. As I remember, some time ago we did get up some figures and it was, as near as I can remember, exactly two cents per, ton for the labor and material. We haven't got the radiators, etc., that the C. F. & I. have in their mines there, probably due to the fact that we have no shortage of water. We have plenty of that there, and our system is absolutely nothing more nor less than pipe lines, hose and nozzles and the man at the end of the nozzle. PRESIDENT PRYDE: I would like to ask Mr. Hair about the cost of the steam. MR. HAIR: That steam we use there in exhausting, of course, is from the fan, and we have a back pressure valve set right here (indicating), from three to four and sometimes five pounds, and the exhaust from the fan was a five or six inch exhaust, and our exhaust into the mine is nothing less than eight inches, and is practically low back pressure you might say, and all those large radiators, that I spoke of, are heated by live steam, and these probably take a little more coal, but as to just what that cost is I couldn't say. As far as the exhaust steam is concerned, you might as well use it in the mine as discharge it outside. MR. HARRINGTON: Mr. Hair, I would like to ask, is this installation on an intake haulage-main haulage course? MR. HAIR: Yes, sir. MR. HARRINGTON: In the winter time, when it is, say between five or ten degrees below zero, how far into that haulage road does the fogging go? MR. HAIR: Well, that goes in half a mile, sometimes in 3,000 feet. MR. HARRINGTON: Wouldn't that interfere pretty seriously with the motor? MR. HAIR: To some extent, but I wouldn't say seriously enough to interefere with the production of coal. We have one mine we are working in two and three-quarters miles. Our mines are all pretty deep, and we don't find it objectionable. I don't believe that it interferes in the production of coal. I don't believe it makes any more difference between a real cold day in winter time than it does in the summer time. MR. HARRINGTON: I was down at Dawson, and in their mines they have an installation very much like Mr. Hair describes, but we went in there one night and stayed all night, getting a certain amount of data, and the fog was intense for-a full half mile; so intense that you could hardly see your hand in front of your face-see your hand that far (indicating) dis-

Jan 1, 1924

PRESIDENT PRYDE: I think that the overcutting machine undoubtedly presents a great many benefits, especially where the roof is frail. I have found a good substitute for the Arcwall, getting a lighter machine by equipping a machine with a turret truck, you get a much lighter weight, and while the cutter is not movable vertically, you cut not on top of the seam, but about the middle of it. MR. SC'HLOSS: I would like to ask Mr. Pryde the advantages of cut- ting with this turret-mounted Shortwall machine. PRESIDENT PRYDE: It is better for development work in narrow places. In development work you have a lot of narrow places. MR. LITTLEJOHN: Mr. Chairman, we were compelled at Winter- quarters, one time, to introduce them for reason of sand rolls'. We have in that mine a condition-we have sand rolls from twelve inches to two and a half feet, sometimes higher than that-usually twelve inches to two and a half feet, and we had to get some of the C. E. 7's on the turret there and used them for advance work not only in the entries, but in rooms; not only in that particular district, but in fact all the districts in the mine-we have abandoned the power trucks. You can cut without unloading, and that is one of the principal advantages, and when the sand rolls come in it enables you to cut over the top of the sand roll, but the particular objection, we were working a nine-foot wall, and some of the coal was twelve feet thick, so that the miners have raised a little objection to the drilling.

Jan 1, 1924

By R. C. Wallace

Since the time when Canada's East and West were joined by the railway, and communication was established into the interior, settlements grew on the southern fringe of the great Precambrian area that formed the northern protaxis of the continent during its vicissitudes of growth. They clung precariously to the fringe of that ancient land, for the Precambrian is not generous to those who wish to live by the fruits of the soil, except in those limited areas where the Pleistocene ice-sheet has been profuse in its gifts of clay to cover the hard surface of the Precambrian rock. Later settlements spread westwards over the expanse of Cretacean plains that now form the wheatfields of the Canadian West; but there still remained in northern and western Ontario, in eastern and northern Manitoba, a pioneer race, to whom agriculture had attractions only in so far that it provided the wherewithal to lay siege to the riches of the Precambrian. And they had a vision beyond their time. More than they knew, they had seized the fact that for the complete rounding out of Canadian national life, a8 well as for the establishing of the necessary contributions towards the economic stability of Canada and its provinces, an industry in mining sh01.dd be well and truly built in the hinterland of the central provinces. Failing the winning of mineral from the rocks, and timber from the forests, there would remain between the East and the West an enormous barrier of unproductive country which would not only be an incubus to the agricultural people in their struggle for economic liberty, but would effectively, and for all time, remain an un-populated void across which the aspirations of East and West would be unable to unite.

Jan 1, 1924

By Robert Strachanm

The East Kootenay coal-field, situated close to the boundary between the provinces of Alberta and British Columbia, is composed of four small areas locally called the Crow's Nest Pass, the Upper Elk, the Flathead and Crown Mountain, and comprises an area of about 3 78 square miles. From eleven to twenty-five seams have been exposed of two feet and over in thickness, with a total thickness of about 200 feet of coal, and reckoning about one hundred feet to be workable, gives an estimate of coal available of about thirty-seven billion tons. The coal is a high-grade bituminous, occasionally tending towards anthracite, and the majority of the seams furnish a. very good quality of coking coal as well as an excellent steam coal. The coal-field is found in the mountain ranges in long narrow strips. The age of the fonnation and the thickness of the covering beds have had considerable influence on the character of the coal, and lateral pressure and disturbances in the process of mountain-building have wrought great changes. With such an abundance of coal, it has been a disappointment that the East Kootenay field has not figured larger industrially. So far only one portion of the coal-field has been utilized. This is the Crow's Nest, where, in 1898, the Crow's Nest Pass Coal Company commenced development. Access to the coal seams was easily obtained, the mountain creeks having eroded away the covering, and mines were driven into the coal seams. In that year about ten thousand tons of coal were produced from the mine at Coal Creek.

Jan 1, 1924

By D. W. McDonald

Coal mining and railway transportation are so closely en-twined and so dependent one upon the other that the failure of one would mean the total collapse of the other. With this indisputable fact in mind, there is no doubt that the operator of each is deeply interested in the other's success. Railway transportation began at the mouth of a coal mine. The first railway car was the English coal-wagon, a crude box on four wooden trowlets, running on wooden rails and holding 1,600 pounds. This was operated by gravity or horse-power in England to convey coal from the mines to the rivers. The first coal-cars used on Nova Scotia railways were of 4 tons capacity with side doors and "V" shaped centres. Then followed flat-bottom, 4-ton cars that operated on tipples, the car bei.ng held in tipple by a chain passing over the top and fastened on either side. Next came the 6-ton car with drop-bottoms, then the 10, 15, 30-ton cars, and now the modern 50 and 100-ton steel cars, equipped with automatic couplers, brakes, and rachet dumping device. Contrast the first coal-car with a modern luxurious pull-man or a I 00-ton coal and ore car, and you have a record of progress in railway transportation. The development of the steam locomotive was no doubt the greatest factor in this progress, but let us not forget that the foundation of all industrial development was and is coal. and that development in mining and railway transportation should keep abreast.

Jan 1, 1924

This growing dependence of Canada upon foreign mineral commodities, just referred to, applies particularly in the direction of the United States. There is, in fact, no more significant feature of Canada's mineral trade than the manner in which it affects the Dominion's commercial standing with that country. Our heavy adverse balance of trade with the United States is perhaps not a matter of such wide concern or frequent comment as was the case two or three years ago. It is, of course, a well-known fact that the Dominion each year buys from the States a volume of goods to a value enormously in excess of our sales to that country. And it has come to be accepted as a ?normal, though not altogether satisfactory, feature of our international commerce that a huge portion of the bill incurred by our American purchases must be met, not by our American sales, but by the proceeds of our sales to other countries, not-ably Great Britain. It is a three-cornered situation in which our trading deficit with the United States is covered largely by our trading surplus with the United Kingdom. In this situation the mineral trade plays a remarkable part. If one delves into the details of our transactions with the United States it will be found that, in one sense, the mineral trade is entirely responsible for the huge annual balance against the Dominion. In fact, Canada gets decidedly better than an even break on Canadian American trade, if one leaves out of account the three mineral groups, "iron and steel", "non- metallic minerals", and "non-ferrous metals".

Jan 1, 1924

THE paper is principally eoncerncd with experimental work carried out the author whilst a number of the metallurgical staff at the Cockle Creek works. The metallurgical has been discussed sufficiently for the reader to follow the course of the experiments but the actual plant has only been described in so far as it effected metallurgical treatment, since the arrangement of such a smelter is a matter of common knowledge.The lead-roasting plant consisted of Godfrey roaster, Dwight-Lloyd maehines and Huntingdon-Heberlein pots. The usual treatment was in the Godfrey furnaces, followed by sintering in the Huntingdon- Heberlein pots. The paper is divided into two parts in the Godfrey furnaces and Huntingdon-Heberlein pots. An account of experiments on the utilization of the hood gases from the Huntingdon-Heberlein pots for acid making...

Jan 1, 1924

By Martin J. Gavin

The results of investigations of the oil-shale resources of the United States were first published by the United States Geological Survey in 1915.1 Other reports 2 have followed. These reports, investigations by private individuals and corporations, and the beginning of the development of an oil-shale industry in this country have aroused considerable interest in the possibilities of these shales as a commercial source of hydrocarbon oils. The Bu- . reau of Mines bas appreciated these possibilities, and since 1916 one or more of its engineers have given all or part of their time to investigations relating to the treatment of oil shales. A short pamphlet a containing general information on the possibilities of oil shale in this country, particularly the shales of the Rocky Mountain district, has already been published. This pamphlet gives methods for assaying the shales of oil and ammonia and contains a bibliography for the use of those desiring to search the literature.

Jan 1, 1924

By George Watkin Evans

The United States Geological Survey has estimated 1 that the State of Washington contains 11,412,000,000 tons of bituminous coal and 52,442,000,000 tons of subbituminous coal, in beds more than 14 inches thick. As the present rate of production is about 4,000,000 tons a year, Washington apparently contains coal enough to supply Pacific coast markets for many years. The character of the coal beds of Washington renders the production of clean coal very difficult, and a considerable proportion of the output is washed before it is marketed. In 1915 Washington ranked fifth among the States in the amount of coal washed, though only twentieth in total output. In that year 37.9 per cent of the coal produced in the State was treated in surface cleaning plants. On account of extensive folding and faulting of the coal measures, mining in Washington presents many difficulties; therefore a description of the methods employed at some of the mines may be useful in planning operations in other regions, and is presented in this bulletin. The coals of Washington differ in quality, ranging from true lignites in Cowlitz County in the southern part of the State to anthracites in the Mount Baker district of Whatcom County, in the north~ rn part. Most of the output consists of subbituminous and bituminous coals, the latter including both coking and noncoking varieties. Analyses of the coals of the State and descriptions of the beds from which the samples were taken have been printed in publications of the United States Bureau of Mines.2 Details of coal beds and analyses of the coals of King, Kittitas, and Pierce Counties have also been published by the Washington Geological Survey; 3 and most of the coal beds of the State are described in some detail in a bulletin of the United States Geological Survey.4 In 1918 mining was in progress at 72 mines in the State 4a; 46 of these mines each employed more than 10 men underground. These mines were distributed as follows: Thurston County, 1; Lewis County, 7; Kittitas County, 14; King County, 16; Pierce County, 6; Skagit County, 1; and Whatcom County, 1. During that year a total of 5,847 men were employed, 4,172 underground and 1,675 on the surface. The average number of days worked in the State was 275, and the average yearly output per man was 706 tons. Coke is made only in Pierce County by four companies, which have a total of 341 beehive ovens. In 1918 they produced 93,699 tons of coke. Up to 1919 mining machines were little used in the State. In 1917 only 6.61 per cent of the coal :produced was undercut by machines. In that year 58.95 per cent of the coal was mined by hand, and 34.44 per cent was shot off the solid. The explosives used were as follows: Black powder, 36.6 per cent; dynamite, 38.l per cent; and permissible, 25.3 per cent. The State of Washington is divided naturally into two parts by the Cascade Mountains which extend north and south somewhat west of the middle of the State. The coal areas east of the range will hereafter be referred to as eastern Washington-though nearly all of it is west of the middle of the State-and that on the west side as western Washington. The geographical distribution of the coal fields is shown in Plate I. Exploration of the State has not been exhaustive enough to preclude the possibility of discovering, besides the foregoing, other districts that contain deposits of coal in commercial quantities.

Jan 1, 1924

By W. A. Dunkley, W. W. Odell

About two-thirds of the manufactured gas supplied to the public by the gas plants in the Illinois district is cnrbureted water gas. The leading generator fuel is coke, ma.de in by-product c.oke ovens or in retorts, chiefly from eastern gas coals. During the fall and winter of 1917-18, when the demand for coke by war industries and the restrictions of the Fuel Administration in connection with the transportation of coke from eastern States made it almost impossible for many gas companies to obtain their coke requireml'nts, several water-gas plants had to use bituminous coal as generator fud. Many operating difficulties were encountered, some of which were solved more or less satisfactorily in different plants. A number of plants attacked the problem rather blindly because facilities for making tests were lacking and because technical men were too busy with labor and supply problems to study thoroughly the conditions involved or to ascertain what other plants had done with this fuel. It was therefore with the hope of assisting the gas industry during this critical period, and of promoting the use of Central District coals for gas making, that the Illinois Mining Investigations, a joint agency of the U. S. Bureau of Mines, the University of Illinois, and the Illinois Geological Survey Division undertook the, tests discussed in this paper. • This report was compiled under the auspices of a technical committee appointed by Gov. Frank 0. Lowden to promote the use of Central District coals in gas manufacture as a war measure. This committee included the following representatives of the various agencies concerned: U. S. Bureau of Mines, E. A. Holbrook and W. W. Odell; Illinois Gas Association, C. W. Bradley and R. B. Harper; University of Illinois, Dean C. R. Richards, Prof. S. W. Parr, and Prof. H. H. Stoek; State Geological Survey Division, F. W. De Wolf, G. H. Cady, a.nd W. A. Dunkley. F. W. De Wolf was chairxnan of the committee and E. A. Holbrook was secretary.

Jan 1, 1924

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

Jan 1, 1924

(Referring to map) If there are any methods to improve on this I would like to have some suggestions on it. The maps there are on a scale of one inch to two hundred feet. At the time of each extension a letter is used and a line drawn across the entry and the room. The date of the extension is given up in the margin of the map. Here is an extension made April 6th. Extension L is shown in each one of the rooms, November 29th. N-you see the two rooms have been finished down into here. 0-the last extension, has just been stopped, and the three working rooms. Now, one of the features of this plan, when the rooms have been stopped, the line is drawn straight across. When the room or entry is still going, there is a small projection beyond the line, indicating that the next cut is changed. When the distance cannot be ascertained by the engineer, he gets the distance from the mine boss or some other source which is reliable, and that is put on in a dotted line. That gives you a complete story. Anyone looking over the map can see immediately every place that was working at the time of this extension, every place that is inaccessible, and get a complete picture. The extension of the coal is put on the extension at each extension. The survey stations are put in, showing each survey point. The pillars when they are pulled-only the pillars that are pulled are cross-hatched. The whole map is in cross-hatch without any regard as to what pillars are pulled. If a little stump is left in, that is shown on the map. The engineer only shows what pillars are pulled that he has actual knowledge of, or has been given to him in detail by the mine foreman. I believe that concludes the work on the mine map, and there is certainly room for a lot of improvement on most of the mine maps which we have been getting into the office. PRESIDENT PRYDE: Does anyone want to ask any questions? Any questions about the leasing regulations? I want to say there are several leases in the Rock Springs field, and when Mr. Smith comes on one of his visits the Rock Springs Institute have asked him to address them on the leasing proposition.

Jan 1, 1924

By George S. Rice

The prevention of coal-mine explosions has been one of the chief purposes of the Bureau of Mines. In facti the first Federal appropriation relating to mining methods, in 1908, authorized the investigation of the causes of mine explosions and the possible methods of preventing them. When that investigation started the mining industry had not determined the real causes of a succession of terrible coal-mine explosions in various countries, culminating in the great disasters at CoulTièl'es, France, and Monongah, W. Va. Coal dust as an agent of widespread explosions had been under suspicion, and watering to allay the dust was recommended by some mining engineers but the watering of coal-mine dust was adopted in comparatively few mines of the United States and Great Britain, and had not been introduced widely in any country except Germany. Rock dusting, another method of preventing explosions of coal dust, was early tested with success by the Bureau of Mines in its fist gallery at Pittsburgh and, beginnig in 1911, at the experimental mine, Bruceton, Pa. Several of the fist publications i of the bureau suggested that rock dust be used in gaseous or dusty bituminous mines, and in 1915 Technical Paper 842 strongly recommended it. Since that time additional tests in the experimental mine have fully confied this :ft judgment.

Jan 1, 1924

By L. C. IlsLey, J. W. Paul, E. J. Gleim

Flame safety lamps have been used in gaseous mines since the Davy lamp was introduced, more than 100 years ago. During the last decade the flame safety lamp has been rapidly replaced by the electric lamp as a device for illuminating the miner's working place; in the United States the electric cap lamp has been widely adopted. For example, in 1911 approximately 45,000 flame lamps and no electric lamps were being used in the Pennsylvania bituminous mines, which were then producing 35 per cent of all the soft coal mined in this country; by 1918 the flame lamps had decreased to 17,000, whereas electric lamps-mostly of one maketotaled nearly 48,000. In Great Britain during the same years the total of 723,934 flame lamps decreased to 590,185 and the electric lamps gained rapidly from 4,298 to 156,521. No later reliable figures are at hand. However, before the flame lamp becomes obsolete, it is fitting that the Bureau of Mines compile a permanent record of a device which has served the mining industry for more than three generations, and not only made possible the development of entire districts that otherwise could not have been worked but undoubtedly saved the lives of thousands of underground workers. Flame safety lamps are capable of doing more than the name indicates. First, under normal conditions, they can be used in a mine atmosphere that contains an explosive mixture of gas and air without great danger of exploding such a mixture, though such use of a flame lamp should not be permitted. Second, to an experienced man they indicate percentages of gas much lower than the explosive limit, and thus can be used to indicate to workers the approach of an unsafe condition in the mine atmosphere. Third, flame lamps will not burn in an atmosphere greatly deficient in oxygen, and they therefore warn the users of such deficiency in time to withdraw to a place of safety. Flame safety lamps are still used rather widely in the United States for general illumination and to a still greater extent for detecting gas. Many coal-producing States require fire bosses to use these lamps in gaseous mines, and the regulations of several States specify that a gIven number of such lamps be kept available for emergency service.

Jan 1, 1924

By W. R. ARGYLE, R. A. SHERMAN, Henry Kreisinger, John Blizard, B. J. CROSS, A. R. Mumford

On entering the World War the United States was confronted with the necessity of building in a short time a large number of ships of tonnage adequate to transport troops and war materials to Europe and to carry food supplies to the allied countries, whose merchant fleets had suffered greatly by submarine warfare. The necessity of building ships quickly led to the formation of the United States Shipping Board, which was charged with the duty of developing an efficient organization for the purpose. Such an organization was developed under the name of the Emergency Fleet Corporation; it was under the control of the Government, but could conduct its business in the most direct way, like a private corporation. In order to build the largest- number of ships possible without drawing too heavily on the steel industry, which was already taxed heavily by the production of munitions, it was decided to build wooden as well as steel ships. These ships were built from a few standard designs to enable a large number of duplicate parts to be fabricated in inland shops and transported by railroad to the shipyards on the seacoast, where they were assembled into ships. In other words, the plan was to manufacture the ships rather than to build them. The shops on the seacoast were reserved to make those parts of the ships' equipment that could not readily be transported. The inland shops made the parts that could be transported to the seacoast by railroad. Among the more important parts of the ships' equipment to be standardized were the boilers. As the Scotch marine boiler in large units is bulky and can not be transported by railroad, and as, for the same capacity,much more steelis needed in its construction than for water-tube boilers, a few simple designs of water-tube boilers were developed that inland shops having ordinary equipment could make in large quantities.

Jan 1, 1924

By WILLARD W. CUTLER

This bulletin reviews, in the light of recent experience, the use of production-decline curves in estimating the future production of oil from wells. It deals with the estimation of the reserves of recoverable oil in properties already producing or in those adjacent to them, takes cognizance of the physical laws governing expulsion of oil from oil sands, and shows how the production-decline curve can be made to utilize these laws in estimating reserves and rates of production. The valuation of oil properties should be based on the total amount of oil recoverable from a property by the methods in use, the rate of recovery, the cost of production, and the selling price. Numerous other curves besides those for reserves and rates of production may be formed from the production-decline curve and will present desired information in a convenient time-saving form. These curves also are described. Methods developed before the production-decline curve method was used are briefly discussed in order that the principles on which estimations of oil reserves are based may be made plain. The construction of curves and tables for estimating future production of individual wells and of average wells in most of the important oil districts of the United States is described and operating problems that may be solved by the use of production-decline curves are discussed. The bulletin does not deal with costs, oil prices, or the methods of evaluating oil properties. Many engineers have amply demonstrated the value of the production- decline curve method by forecasting within reasonable limits the production of many thousands of wells and tracts. The value of similar estimates depends however, on (1) the application of trustworthy methods; (2) the care and judgment of the estimator; and (3) the length and reliability of the records and the accuracy of ofher information used in estimating future production. When adequate records and information are available, experience has shown that It qualified engineer can forecast production far more accurately than has been deemed possible, except where the usual conditions governing the expulsion of oil from a sand have been radically changed by applying compressed air or by flooding with water, or, to a less degree, by using vacuum. In general, the production-decline curve method, though there are limits to its accuracy, is far more trustworthy than any other.

Jan 1, 1924

By G. L. Oldright

"The various districts in the United States where complex lead-zinc ores occur are too well known to require description, there being hardly a mining State with any large amount of ores of either metal that is free from this problem. This paper briefly presents developments in the volatilization process, as applied to the treatment of such ores, since the data in Bureau of Mines Bulletin 211** were published. In that bulletin, among the many types of ore treated, examples are given of the treatment of lead-zinc ores by the chloride volatilization process for the separation of lead. An outline of the general process, with views of the rotary kiln, ore feeder, firing system (these three features resemble closely those of cement-kiln practice), dust chambers, and a Cottrell precipitator to remove the fume from the gas, are also shown in that bulletin, to which the reader is referred for the results obtained, and for practical details of operation. The small initial cost of a volatilization plant, and its adaptability for use in isolated districts were emphasized.In general, it was found that when an intensely oxidizing atmosphere was maintained in the furnace, a good lead-zinc separation could be made. Therefore, a heavy sulphide ore would have to be preroasted, and enough air would have to be admitted to obtain complete combustion of whatever fuel might be used.The work done by private companies and the bureau since the data for Bulletin 211 were obtained, indicates that the ores most immediately amenable to treatment by volatilization are of two types. The first is an oxidzed lead. silrer ore whose variable lime content makes it impractical to chloridize the ore for acidulated brine leaching, and whose base metal content makes treatment by cyanidattion unfeasible, The second type is the lead-zinc ore mentioned above, and is the one on which data are available for publication at present. This article Chows what ores of this latter type are amenable to treatment by volatilization, by giving briefly some of the more important physical and chemical properties an ore should preferably possess. Several examples are given from both laboratory experimental work, and from practice in the field, showing various phases of the volatilization process."

Nov 1, 1923

By W. M. Myers

Water has been commonly used as a collecting medium in many instruments employed in the sampling of dusty atmospheres in mines** add industrial plants, and for this purpose has much to recommend it, particularly the following factors:1.,Water is a very efficient dust collector.2.,Distilled water of great purity may be readily obtained at slight expense. The analytical error introduced by the extremely small amount of foreign matter in carefully distilled water is very small,3.,Water is a very convenient medium with which to work as all the analytical operations of diluting, aliquoting, and filtering are readily and speedily carried out. Water has therefore been used extensively in such instruments as the Palmer apparatus, the Greenburg-Smith impinger, and the dust collector recently described by Drinker, Thompson, and Fitchet. The Bureau of Mines has conducted investigations in many metal-mining districts of the country, determining of dust the nature and amount of dust present in working places, its effect the health of workers, and what precautions may be taken to decrease the hazard of exposure to dangerous dusts. The Bureau is therefore interested in any factor that affects the accuracy of dust sampling.

Nov 1, 1923

By S. P. Kinney, P. H. Royster, T. L. Joseph

An investigation of the production of iron in the blast furnace is obviously not an easy subject for research . Enough is known of the mechanical , thermal and chemical conditions existing inside the furnace to say certainly that they are complicated. Furnace operators have found that the process is sensitive to a number of known and to many unknown operating conditions . In order to form any conclusions of value , it seems necessary to collect a large amount of data taken with considerable care and accuracy. These facts make a blast furnace research difficult but not impossible . The most serious obstacle in attacking the problem comes from the fact that it is useless in the design and operation of the blast furnace to use the method of " trial and error , which has proved valuable in so many other industrial problems . The variables are so interrelated and are so dependent one on the other that the number of experimental combinations to be tried is enormous . There are certainly not less than twenty factors in furnace operation and design that are known to influence the results . This is apparent if it is remembered that a phrase like " size and shape of the furnace" includes height of the furnace , height , diameter and angle of the bosh , inwall batter , stockline diameter , and furnace volume ; and that a phrase like " chemical and physical properties of the fuels charged " includes size and shape of the lumps , density, porosity and strength of the coke , in addition to its chemical analysis . Let us suppose that we need choose for each of twenty factors one of two values , for example , suppose we must say only that the furnace shall be " tall " or " short , " that the bosh angle shall be " flat " OF "steep , that the ore shall be " coarse " or " fine , " or that the blast has to be "hot" or " cold , " the number of resulting combinations is more than one million . In putting twenty pennies on the table , either heads up or tails up, the number of permutations possible is the twentieth power of two , slightly more than one million. It is obvious , therefore , that some sort of mathematical relationship , a set of rules of thumb , laws , curves or the like , are needed . Whether the relationships , curves or formulas are derived from experiment , from theory, or from mere guess -work, makes no difference provided they agree with the known facts . If they do not agree with known facts , they are worthless no matter what their origin or how weighty the " authority" vouching for them. Few such relationships have appeared in blast- furnace literature , and it may be doubted whether such formulas can be discovered .

Sep 1, 1923