Transactions of the American Society of Civil Engineers Part 16

_Seventh._--The main shaft practically reached only to the second vein; its extension to the third and deepest vein was not used.

_Eighth._--Plans of the workings of the second and third veins were not up to date. The last survey recorded on them was that of June, 1909. This would have made rescue work almost impossible to men not familiar with the mine.

_Ninth._--The inside survey of the mine was not connected with the outside survey.

Would it not be possible for the United States Geological Survey to enforce rules which would prevent the existence of conditions such as those mentioned? The Survey is doing wonderful work, as shown by the rescue of twenty miners at Cherry one week after the conflagration; but there is no doubt that perhaps all the men could have been saved if telephone communications with the outside had been established.

Telephone lines to resist any kind of a fire, can easily be installed, and the expense is small, almost negligible when one considers the enormous losses suffered by the mine owners and by the families of the victims.

H. G. STOTT, M. Am. Soc. C. E.--The curves shown by Mr. Wilson give a clear general idea of the relative efficiencies of steam and gas engines when treated from a purely theoretical thermodynamic point of view. This point of view, however, is only justified when small units having a maximum brake horse-power not exceeding 1,000 are considered.

The steam engine or turbine operating under a gauge pressure of 200 lb.

per sq. in., and with 150 superheat, has a maximum temperature of 538 Fahr. in its cylinder, while that of the gas engine varies between 2,000 and 3,000 Fahr.

The lubrication of a surface continually subjected to the latter temperature would be impossible, so that water jackets on the cylinders and, in the larger units, in the pistons become absolutely necessary. As the cylinders increase in diameter, it is necessary, of course, to increase their strength in proportion to their area, which, in turn, is proportional to the square of the diameter. The cooling surface, however, is only proportional to the circ.u.mference, or a single function of the diameter. Increasing the strength in proportion to the square of the diameter soon leads to difficulties, because of the fact that the flow of heat through a metal is a comparatively slow process; the thick walls of the cylinders on large engines cannot conduct the heat away fast enough, and all sorts of strains are set up in the metal, due to the enormous difference in temperature between the inside and the jacket lining of the cylinder.

These conditions produce cut and cracked cylinders, with a natural resultant of high maintenance and depreciation costs. These costs, in some cases, have been so great, not only in the United States, but in Europe and Africa, as to cause the complete abandonment of large gas engine plants after a few years of attempted operation.

The first consideration in any power plant is that it shall be thoroughly reliable in operation, and the second is that it shall be economical, not only in operation, but in maintenance and depreciation.

Therefore, in using the comparative efficiency curves shown in Mr.

Wilson's paper it should be kept in mind that the cost of power is not only the fuel cost, but the fuel plus the maintenance and depreciation charges, and that the latter items should not be taken from the first year's account, but as an average of at least five years.

The small gas engine is a very satisfactory apparatus when supplied with good, clean gas, and when given proper attention, but great caution should be used before investing in large units, until further developments in the art take place, as conservation of capital is just as important as conservation of coal.

B. W. DUNN, Esq.[31] (by letter.)--The growing importance of investigations of explosives, with a view to increasing the consumer's knowledge of proper methods for handling and using them, is evident when it is noted that the total production of explosives in the United States has grown from less than 9,000,000 lb. in 1840 to about 215,000,000 lb.

in 1905. Table 5 has been compiled by the Bureau of Explosives of the American Railway a.s.sociation.

TABLE 5.--Manufacture of Explosives in the United States, 1909.

---------------------+-------------+------------------------------ Kind of explosives. | Number of | Maximum Capacity, in Pounds.

| factories. +--------------+--------------- | | Daily. | Annual.

---------------------+-------------+--------------+--------------- Black powder | 49 | 1,220,150 | 366,135,000 High explosives | 37 | 1,203,935 | 361,180,500 Smokeless powders | 5 | 75,686 | 22,705,800 ---------------------+-------------+--------------+---------------

The first problem presented by this phenomenal increase relates to the safe transportation of this material from the factories to points of consumption. A package of explosives may make many journeys through densely populated centers, and rest temporarily in many widely separated storehouses before it reaches its final destination. A comprehensive view of the entire railway mileage of the United States would show at any instant about 5,000 cars partially or completely loaded with explosives. More than 1,200 storage magazines are listed by the Bureau of Explosives as sources of s.h.i.+pments of explosives by rail.

The increase in the demand for explosives has not been due entirely to the increase in mining operations. The civil engineer has been expanding his use of them until now carloads of dynamite, used on the Isthmus of Panama in a single blast, bring to the steam shovels as much as 75,000 cu. yd. of material, the dislodgment of which by manual labor would have required days of time and hundreds of men. Without the a.s.sistance of explosives, the construction of subways and the driving of tunnels would be impracticable. Even the farmer has awakened to the value of this concentrated source of power, and he uses it for the cheap and effective uprooting of large stumps over extended areas in Oregon, while an entire acre of subsoil in South Carolina, too refractory for the plow, is broken up and made available for successful cultivation by one explosion of a series of well-placed charges of dynamite. It has also been found by experience that a few cents' worth of explosive will be as effective as a dollar's worth of manual labor in preparing holes for transplanting trees.

The use of explosives in war and in preparation for war is now almost a negligible quant.i.ty when compared with the general demand from peaceful industries. With the completion of the Panama Ca.n.a.l, it is estimated that the Government will have used in that work alone more explosives than have been expended in all the battles of history.

Until a few years ago little interest was manifested by the public in safeguarding the manufacture, transportation, storage, and use of explosives. Anyone possessing the necessary degree of ignorance, or rashness, was free to engage in their manufacture with incomplete equipment; they were transported by many railroads without any special precautions; the location of magazines in the immediate vicinity of dwellings, railways, and public highways, was criticized only after some disastrous explosion; and the often inexperienced consumer was without access to a competent and disinterested source of information such as he now has in the testing plant at Pittsburg so well described by Mr.

Wilson.

The first general move to improve these conditions is believed to have been made by the American Railway a.s.sociation in April, 1905. It resulted in the organization of a Bureau of Explosives which, through its inspectors, now exercises supervision over the transportation of all kinds of dangerous articles on 223,630 of the 245,000 miles of railways in the United States and Canada. A general idea of the kind and volume of inspection work is shown by the following extracts from the Annual Report of the Chief Inspector, dated February, 1910:

1909. 1908.

"Total number of railway lines members of Bureau December 31st 172 158 Total mileage of Bureau lines December 31st 209,984 202,186 Total number of inspections of stations for explosives 6,953 5,603 Number of stations receiving two or more inspections for explosives 1,839 1,309 Total number of inspections of stations for inflammables 6,950 1,098 Number of stations receiving two or more inspections for inflammables 1,886 ....

Total number of inspections of factories 278 270 Number of factories receiving two or more inspections 75 69 Total number of inspections of magazines 1,293 1,540 Number of magazines receiving two or more inspections 349 361 Total number of boxes of high explosives condemned as unsafe for transportation 10,029 4,852 Total number of kegs of black powder condemned as unsafe for transportation 1,468 531 Total number of cars in transit containing explosives inspected 475 448 Total number of cars in transit showing serious violations of the regulations 168 197 Total number of inspections of steams.h.i.+p companies' piers (inflammable, 75; explosive, 63) 138 ....

Total number of inspections made by Bureau 16,087 8,959 Total number of lectures to railway officials and employes and meetings addressed on the subject of safe transportation of explosives and other dangerous articles 215 171

1909. 1908. 1907.

"Total number of accidents resulting in explosions or fires in transportation of explosives by rail 12 22 79 Total known property loss account explosions or accidents in transporting explosives by rail $2,673 $114,629 $496,820 Total number of persons injured by explosions in transit 7 53 80 Total number of persons killed by explosions in transit 6 26 52

"During the same period reports have been rendered to the Chief Inspector by the Chemical Laboratory of the Bureau on 734 samples, as follows:

Explosives 211 Fireworks 186 Inflammables 304 Paper for lining high explosive boxes 31 Ammunition 2 ---- Total 734

"As a means of ensuring the uniform enforcement of the regulations, by a well grounded appreciation of their significance and application, the lectures delivered by representatives of the Bureau have proved most successful. The promulgation of the regulations is not of itself sufficient to ensure uniformity or efficiency in their observance, and so these lectures form a valuable supplement to the inspection service. They have been successfully continued throughout the year, and the requests for the delivery of them by the managements of so many of the members.h.i.+p lines, is a convincing testimonial of the high esteem in which they are held.

"While the lectures are primarily intended for the instruction and information of the officials and employes of the railway companies, and especially of those whose duties bring them into immediate contact with the dangerous articles handled in transportation, the manufacturers and s.h.i.+ppers are invited, and they have attended them in considerable numbers. Many of this cla.s.s have voluntarily expressed their commendation of the lectures as a medium of education, and signified their approval of them in flattering terms.

"The scope of these lectures embraces elementary instruction in the characteristics of explosives and inflammables and the hazards encountered in their transportation and in what respects the regulations afford protection against them. The requirements of the law, and the attendant penalties for violation, are fully described.

Methods of preparation, packing, marking, receiving, handling and delivering, are explained by stereopticon lantern slides. These are interesting of themselves, and are the best means of stamping the impression they are intended to convey upon the minds of the audiences, and are always an acceptable feature of the lectures. The reception generally given to the lectures by those who have attended them, often at the voluntary surrender of time intended for rest while off duty, may be stated as an indication that the subject matter is one in which they are interested.

"The facilities of the Young Men's Christian a.s.sociation, in halls, lanterns and skilled lantern operators, have been generously accorded and made use of to great advantage, in connection with the lectures at many places. The co-operation of this a.s.sociation affords a convenient and economical method of securing the above facilities, and the a.s.sociation has expressed its satisfaction with the arrangement as in line with the educational features which they provide for their members.

"During the year 1909, 215 lectures were delivered at various points throughout the United States."

The Bureau of Explosives, of the American Railway a.s.sociation, and the Bureau of Mines, of the United States Geological Survey, were independent products of a general agitation due to the appreciation by a limited number of public-spirited citizens of the gravity of the "explosive" problem. It is the plain duty of the average citizen to become familiar with work of this kind prosecuted in his behalf. He may be able to help the work by a.s.sisting to overcome misguided opposition to it. Evidences of this opposition may be noted in the efforts of some s.h.i.+ppers to avoid the expense of providing suitable s.h.i.+pping containers for explosives and inflammable articles, and in the threats of miners'

labor unions to strike rather than use permissible explosives instead of black powder in mining coal in gaseous or dusty mines.

Too much credit cannot be given Messrs. Holmes and Wilson, and other officials of the Technologic Branch of the United States Geological Survey, for the investigations described in this paper. They are establis.h.i.+ng reasonable standards for many structural materials; they are teaching the manufacturer what he can and should produce, and the consumer what he has a right to demand; with scientific accuracy they are pointing the way to a conservation of our natural resources and to a saving of life which will repay the nation many times for the cost of their work.

When these facts become thoroughly appreciated and digested by the average citizen, these gentlemen and their able a.s.sistants will have no further cause to fear the withdrawal of financial or moral support for their work.

HERBERT M. WILSON, M. Am. Soc. C. E. (by letter).--The Fuel Division of the United States Geological Survey has given considerable attention to the use of peat as a fuel for combustion under boiler furnaces, in gas producers, and for other purposes. It is doubtless to this material that Mr. Allen refers in speaking of utilizing "marsh mud for fuel," since he refers to an address by Mr. Edward Atkinson on the subject of "Bog Fuel"

in which he characterized peat by the more popular term "marsh mud."

In Europe, where fuel is expensive, 10,000,000 tons of peat are used annually for fuel purposes. A preliminary and incomplete examination, made by Mr. C. A. Davis, of the Fuel Division of the Geological Survey, indicates that the peat beds of the United States extend throughout an area of more than 11,000 sq. miles. The larger part of this is in New England, New York, Minnesota, Wisconsin, New Jersey, Virginia, and other Coastal States which contain little or no coal. It has been estimated that this area will produce 13,000,000,000 tons of air-dried peat.

At present peat production is in its infancy in the United States, though there are in operation several commercial plants which find a ready market for their product and are being operated at a profit. A test was made at the Pittsburg plant on North Carolina peat operated in a gas producer--the resulting producer gas being used to run a gas engine of 150 h.p.--the load on which was measured on a switch-board.

Peat containing nearly 30% of ash and 15% of water gave 1 commercial horse-power-hour for each 4 lb. of peat fired in the producer. Had the peat cost $2 per ton to dig and prepare for the producer, each horse-power-hour developed would have cost 0.4 of a cent. The fuel cost of running an electric plant properly equipped for using peat fuel, of even this low grade, in the gas producer would be about $4 per 100 h.p.

developed per 10-hour day.

Equally good results were procured in tests of Florida and Michigan peat operated in the gas producer. The investigations of peat under Mr. Davis include studies of simple commercial methods of drying, the chemical and fuel value, a.n.a.lyses of the peat, studies of the mechanical methods of digging and disintegrating the peat, and physical tests to determine the strength of air-dried peat to support a load.

The calorific value of peat, as shown by numerous a.n.a.lyses made by the United States Geological Survey, runs from about 7,500 to nearly 11,000 B.t.u., moisture free, including the ash, which varies from less than 2% to 20%, the latter being considered in Europe the limit of commercial use for fuel. a.n.a.lyses of 25 samples of peat from Florida, within these limits as to ash, show a range of from 8,269 to 10,865 B.t.u., only four of the series being below 9,000 B.t.u., and four exceeding 10,500 B.t.u., moisture free. Such fuel in Florida is likely to be utilized soon, since it only needs to be dug and dried in order to render it fit for the furnace or gas producer. Many bituminous coals now used commercially have fuel value as low as 11,000 B.t.u., moisture free, and with maximum ash content of 20%; buckwheat anthracite averages near the same figures, often running as high as 24% ash.

One bulletin concerning the peats of Maine has been published, and another, concerning the peat industries of the United States, is in course of publication.

Mr. Bartoccini asks whether it would not be possible for the United States Geological Survey to enforce rules which would prevent the existence of conditions such as occurred at the mine disaster of Cherry, Ill.

The United States Government has no police power within the States, and it is not within its province to enact or enforce rules or laws, or even to make police inspection regarding the methods of operating mining properties. The province of the mine accidents investigations and that of its successor, the Bureau of Mines, is, within the States, like that of other and similar Government bureaus in the Interior Department, the Department of Agriculture, and other Federal departments, merely to investigate and disseminate information. It remains for the States to enact laws and rules applying the remedies which may be indicated as a result of Federal investigation.

Investigations are now in progress and tests are being conducted with a view to issuing circulars concerning the methods of fighting mine fires, the installation of telephones and other means of signaling, and other subjects of the kind to which Mr. Bartoccini refers.

Much as the writer appreciates the kindly and sympathetic spirit of the discussion of Messrs. Allen and Bartoccini, he appreciates even more that of Colonel Dunn and Mr. Stott, who are recognized authorities regarding the subjects they discuss, and of Messrs. Kreisinger and Snelling, who have added materially to the details presented in the paper relative to the particular investigations of which they have charge in Pittsburg.