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By R. P. Rothwell

AT this our first meeting I beg to call the attention of the members of our Institute to what is certainly a question of the greatest possible importance to the industries we represent; and more particularly to the welfare of the coal and iron trades: I refer to the enormous waste of coal in mining and in its preparation for market, as now practised in our anthracite coal-fields. I t is a fact which many of you can certify to, that we are wasting fully me-half of all the coal in the veins we are now working, and there are cases, which might be mentioned where this proportion, immense as it is, has been greatly exceeded. The popular belief that our deposits of anthracite coal are "practically inexhaustible," is very far from being founded on facts. On the contrary, supposing the present rate of increase in the production to be maintained, it is probable that a maximum yield for our coal-fields would be attained in about fifteen years ; there are in fact some of our smaller basins where the principal veins are nearly exhausted and the production has already attained its maximum. There are others, again, where the depth attained-and it must be borne in mind that we commenced working at the surface outcrop moderate though it is (scarcely ever reaching eight hundred feet), has so increased the cost of mining as to imperil the capital invested, and though it requires but little foresight to predict the time when the difficulties of mining will be very considerably increased by reason of the greater depth, greater quantity of water, fire-damp, and other fruitful sources of cost, yet, ignoring these recognized facts, we continue to waste more than one-half of the coal where it is obtained with the least danger, expense, and trouble, that is, near the surface-either above water-level or at a moderate depth . below it. The inspection of almost any accurate mine map will satisfy you that, on an average, we leave fully one-third. of the coal in the ground as pillars to support the roof; in some places more than one-third thus remains, while it is very rare that less than one quarter is left. In almost every case this coal is absolutely lost, for it will very rarely pay to reopen gangways and lay roads to it after that portion of the mine has been abandoned. Is it necessary in all cases to support the roof, and where it is, may not some artificial

By R. W. Raymond

THE question, what is the best proportion among weight, fall, and speed of stamps, is one which has not yet received thorough and systematic examination. In considering the economical application of stamping machinery, we meet, at the beginning, with serious difficulties in obtaining accurate data for comparison. The weight and fall of stamps vary as the shoes and dies wear out; and this may lead to a change of speed also. Moreover, defects in engines, boilers, or machinery for the transmission of power, may occasion serious losses, which cannot fairly be charged to the arrangements of the stamps proper. Again, the capacity of stamp-mills is directly dependent, in some degree, upon the nature and extent of discharge, fineness of screens, and other peculiarities of the battery. Finally, the hardness and tenacity of the rock crushed varies so much that comparisons between different localities cannot be implicitly trusted. The safest experiments are those made in the same mill, by changing first one and then another condition of working; but this is seldom possible for such conditions as weight and lift of stamps, and only within narrow limits for their speed. We may eliminate of friction, transmission, and generation of power, in the case of stamps, by measuring the power actually developed by their fall. Thus, the weight, multiplied into the fall in feet, and the number of drops per minute, gives us exactly the number of foot-pounds exerted by each stamp. Dividing by 33,000, the number of foot-pounds per minute in one-horse power, we have the horse-power per stamp, from which the effective power of the whole mill may be obtained. Dividing the amount of rock crushed daily by the effective horse-power, gives us the daily amount per horse-power ; and this is the best measure that can be obtained for the effectiveness of the stamps. A complete discussion of the subject would require us to determine the exact influence of the discharge, etc., and the exact resistance offered by different classes of rocks, for both of which points the data are wanting. Professor J. D. Hague, in the third volume of the United States Geological Exploration of the Fortieth Parallel, gives a valuable

By R. W. Raymond

PROFESSOR W. P. BLAKE, in a note to his Catalogue of California Minerals, pointed out that the milling districts of the Pacific slope are arranged in parallel zones, following the prevailing direction of the mountain ranges. This interesting generalization has been more frilly illustrated and connected with the geological history of the country by Mr. Clarence King, who sums up the observed phenomena as follows : " The Pacific coast ranges upon the west carry quicksilver, tin, and chromic iron. The next belt is that of the Sierra Nevada and Oregon Cascades, which, upon their west slope, bear two zones, a foot-hill chain of copper mines, and a middle line of gold deposits. These gold veins and the resultant placer mines extend far into Alaska, characterized by the occurrence of gold in quartz, by a small amount of that metal which is entangled in iron sulphurets, and by occupying splits in the upturned metamorphic strata of the Jurassic age. Lying to the east of this zone, along the east base of the Sierras, and stretching southward into Mexico, is a chain of silver mines, containing comparatively little base metal, and frequently included in volcanic rocks. Through Middle Mexico, Arizona, Middle Nevada, and Central Idaho is another line of silver mines, mineralized with complicated association of tli6 base metals, and more often occurring in older rocks. Through New Mexico, Utah, and Western Montana lies another zone of argentiferous galena lodes. To the east, again, the New Mexico, Colorado, Wyoming, and Montana gold belt is an extremely well-defined and continuous chain of deposits." These seven longitudinal zones or chains of mineral deposits must

By Martin Coryell, Eckley Coxe, R. P. Rothwell

WILKES-BARRE, PA., April, 1871. THE great development of the mines and metallurgical works of this country during the last few years, accompanied as it has been by the investment of enor¬mous sums of money in purchasing lands, and in the erection of improvements, requires that advantage should be taken of the accumulated knowledge of engi¬neers, superintendents, and others, in mastering the problems which are con¬stantly presenting themselves for our action. Among those may be mentioned the consideration of more economical systems of mining in our coal and metal¬liferous mines, improved methods of transportation above and below ground, unwatering and ventilating mines, the mechanical preparation of coal and other minerals, the various metallurgical processes, and, in fact, every question tending to the attainment of two great objects 1st. The more economical production of the useful minerals and metals. 2d. The greater safety and welfare of those employed in these industries. In European countries, where the arts of mining and metallurgy have long been the subject of the most careful study, no means have been found so effectual in attaining the end above proposed as the free interchange of experience among those actually engaged in these industries, and this object has been accomplished, mainly, through the medium of institutes, associations or societies, composed of those engaged in these occupations, and by the- periodical publication of essays or papers, communicated to such societies by their members. It must be evident to all practical men that the interchange of the varied experience of those engaged in such occupations in this country could not fail to advance very materially the desired objects; it is, therefore, proposed to establish an American Institute of Mining Engineers, which will hold its meetings periodically in the great mining and metallurgical centres, where works of interest, such as mines, machine shops, furnaces, and other metallurgical works, can be inspected, and the members exchange their views, and consult for mutual advantage upon the difficulties encountered by each; these transactions or proceedings, when published, would form a most valuable and greatly-needed addition to our professional literature. It is proposed that a meeting of those sympathizing with the object above men¬tioned shall be called for the purpose of organizing such an association, the place and time of meeting being Wilkes-Barre, Pa., and the month of April or May. Communications indicating the opinion and wishes of all, both as to these points, and also as to the organization and objects of the Institute, will be gladly received by any of the undersigned, and a notice of the date of meeting, which will be arranged to suit the greater number, will be duly communicated. Any

Jan 1, 1873

Jan 1, 1912

Jan 1, 1879

By AIME AIME

PLANS for the Semi-centennial Meeting have almost reached completion, although in any undertaking of such magnitude a few changes are always to be expected at the last moment. As worked out up to the time of going to press, the program of the meeting is shown below. The headquarters will be the Irem Temple, in Wilkes-Barre.

Jan 1, 1921

By A. T. Schwennesen

Every engineer has occasion to trace or copy a map, plan, or other drawing on paper too thick for the ordinary way of using tracing-cloth or tracing-paper. When the figure is small and simple a copy may be made by holding the original against a window-pane, coverin& it with the paper, and tracing direct by the aid of the strong sunlight from outside. The need of utilizing this principle on a larger scale and in a more convenient position led Dr. J. C. Branner to plan the table of which the following is a description : This table was first made in the form of an adjustable glass-top table with a mirror beneath, in 1887, while Dr. Branner was State Geologist of Arkansas. Later it was modified as experience suggested until the form as here described was evolved. The device consists essentially of a drafting-table with a plate-glass top, upon which the original drawing and the paper are laid, and a mirror mounted underneath to reflect the light of the sky up through the drawing. The glass top is hinged and fitted with two arms and thumb-screws, so that it can be raised and fixed to any position, either inclined or horizontal. The mirror is pivoted and revolves about a horizontal axis, so that it may be tilted to any angle. The hood of cardboard or black cloth prevents the reflection of light from the tracing, and may or may not be attached to the table.

Jan 1, 1912

By Robert H. Richards

THE Institute of Mining Engineers has shown so much interest in the educational problem of profitably combining theory and practice, that it seems especially appropriate to lay before its members the methods and aims of the mining laboratory of which I have charge, and in which one form of combination of hand with head work is now being tried. If anything may be contributed toward the solution of this problem by the discussion which follows, my purpose mill be attained. Whether it was wise or not to establish a mining school so far from the principal mining centres, does not now enter into the question. Given, a mining school already begun, how shall it be made most efficient in developing engineers who are trained to think for themselves as well as versed in the works of others ? This is the question with which we have had to deal. In considering the bearing of this laboratory work upon the students' preparation, it will be convenient to take it up under five different heads: 1. The methods and aims of the laboratory. 2. The advantage to students of having a part, at least, of their practical work in the curriculum of their school. 3. The advantage to be derived by mine; and works. 4. Degree of accuracy which may be attained in working ores on a small scale. 5. Reslts of work in the laboratory. 1. The Methods and Aims of the Laboratory.—During the May meeting of 1873, held in Boston, I had the privilege of reading before you a paper stating the plan; and aims of this laboratory. Since that time me have been constantly following out those plans, and are more than ever convineed that me are working in the right direction. We do not feel that the time we have spent has been in any sense thrown away. Perhaps the aims of the laboratory can be most clearly shown by illustration. Many young engineers have school thinking that they know everything. They go to the works, and expect to teach the superintendent something and the men a good deal, regardless of the fact that it is this spirit that has prejudiced workmen against schoolmen. They are often more trouble than they

Jan 1, 1879

By Charles Dorrance

Culm is a general term used in the anthracite regions for many years to denote a mixture of coal, bony coal and impurities which is sent to the refuse-banks. Thus, 35 years ago culm contained the pea and buckwheat sizes of anthracite; but to-day, and as mentioned in this paper, culm is used specifically to denote the material which passes through the smallest screen in the anthracite-breaker. The smallest size of commercial anthracite is known as No. 3 buckwheat, barley, or bird's-eye coal, and is ordinarily made through a round-punched plate having openings & in. in diameter, and over a round-punched plate with openings 3/32 in. or 1/16 in. in diameter. Thus culm will consist of coal, bony coal, slate, gravel, iron pyrite, etc., ranging in size from 3/32 in. down to dust. Other local terms for culm are " slush," " silt," and " dirt." The first experiments towards the utilization of anthracite culm by briquetting, and the first briquetting-work done in this country, were in 1872 at Port Richmond Piers, Philadelphia, Pa., by E. F. Loiseau.1 Clay was used as a binder and the finished briquette was water-proofed with shellac, etc. Excessive cost was given as the reason for discontinuing work at this plant.

Jan 1, 1912

By Carle R. Hayward

The growing importance of metallography has caused a corresponding interest in the improvement of apparatus for preparing specimens of metals and alloys for microscopic examination. The purpose of this paper is to describe an electric heating-furnace, a grinding- and polishing-machine, and a device for mounting specimens, which are used in the metallographical work at the Massachusetts Institute of Technology. These three pieces of apparatus were designed and made in the laboratory of the Institute, and each possesses some original features which may be of interest. Electric Heating-Furnace. The accurate control of heat necessary for metallographic work is best obtained by the electric-resistance furnace. Uufortunately, however, even the platinum-wound furnaces cleteriorate with use and ultimately burn out, while the cheaper resistance-materials are often short-lived. Since the resistance-coil must be replaced from time to time, it is of advantage to be able to make this change with as little trouble as possible, and this is an important feature in the furnace shown in Fig. 1. A is a cylindrical galvanized-iron can, with two handles, B. A porcelain tube, C, passes through the central hole in the cover of the can and rests upon the asbestos disk, D; the bottom of the tube is held in place by the asbestos ring, 3. The space, F, around the tube is filled with powdered magnesia. G is an ordinary assay-crucible, with the cover inverted so as to present a smooth top for supporting a second porcelain tube, H. The latter is wound with " Excello " resistance-tape, 0.014

Jan 1, 1912

By Charles R. Keyes, D. F. Riddell

For a period of several years, and in a large number of oases, the Metallurgical Laboratories of the New Mexico School of Mines were employed in umpire work. During this time many important local problems mere solved. Against the results of careful chemical analyses of ores, assay-returns mere often checked. In many cases the assay-methods of mine and custom-smelter were compared, and both often found faulty for the ore concerned. A wide range of ores was covered. Many of the chemical analyses and assays were made by Dr. F. C. Lincoln, Professor of Metallurgy, now of the Montana State School of Mines. A varied series of instructive assays was prepared by Prof. R. B. Brinsmade, now of the West Virginia State University. Single assays and given series of tests were undertaken by H. T. Goodjohn, now chief chemist to the Cia. Metalurgica de Torreon, Coahuila, Mexico; by H. J. Hub-bard, now superintendent of the Butters Divisadero Mines, Jocoro, San Salvador, C. A.; by E. D. Morton, now superintendent of the Arizona & Nevada Copper Mining Co., at Lunning, Nev.; and by A. W. Edelen, now superintendent of the Angangueo Unit of the American Smelting & Refining Co., in Michoacan, Mexico. A critical comparison of assay-methods that were found to be followed in the case of certain gouge-ores mined in the Mimbres range in New Mexico, and about which there had been much controversy, was made by D. F. Riddell, then Acting Professor of Assaying, and now superintendent of the Providentia Mines Co. of Parral, in Chihuahua, Mexico. To him is due the credit of much that is contained in the following notes, which he has generously permitted to be used in advance of the publication of the complete results.

Jan 1, 1912

By N. S. Keith

This question is suggested by a statement made by Dr. Siemens, widely printed in the journals of the day, that a continuous rod of copper, thirty miles in length and three inches in diameter, is capable of conveying that distance, electrically, energy equal to 1000 horse-power. It is not attempted to advance the statement that the source of power shall be zinc, nor even coal, but waterfalls, which from their situation are not practically available for manufacturing establishments in their immediate vicinity. In order to fully consider this subject,, we must understand the doctrine, I may say the science, of the correlation of the forces, so called. We must understand that all matter is endowed with an amount of force, and that each atom and molecule, simple and compound, has its specific portion of the whole. This force, at rest, is called latent heat, intrinsic energy, or potential. In motion it is called heat, light, electricity, chemical affinity, attraction, magnetism, power, etc., according to its sensible manifestations. These are the effects of the one force active in different substances, or in different assemblages of matter. Force put in motion comes to rest by reason of the resistance to motion which it eucounters; in overcoming

Jan 1, 1879

By J. M. Clark

For some years past, those interested in the development of the increasingly important mining industry of Canada, havc urged the adoptioi~ by the Dominion Parliament of a federal mining-law, which would have the force and stability of statutory enactment. At present, placer-mining in the Yukon Territory is governed by the Yukon Placer Mining Act. All other mining under federal jurisdiction is governed by Orders in Council and Ministerial Iiegulations. In the earlier stages of development, it is perhaps a matter of neces~ity that these important matters should be so dealt with; but it is now felt that the time has come when mining-rights in the extensive regions under federal control should be put on a permanent basis, and that any changes required from timc to time should be made only after full and open discu~sioii in Parliament. A short sketch will suffice to indicate how vast and varied the interests affected really are. When the Dominion of Canada mas constituted by the Inlperial Statute known as the British North America Act of 1867 (which into force by proclamation on July 1 of that year), it comprised only the present Provinces of Ontario, Quebec, Nora Scotia, and New Brunswick; but provision was made for the inclusion of Newfoundland, Prince Edward Island, British Columbia, Rupert's Land, and the North West Territories. Subsequently Rupert's Land and the North West Territories were acquired, the Crown Colonies of British Columbia and

Jan 1, 1912

By Douglas Bunting

With the gradual exhaustion of the upper veins in the anthracite coal-fields, the problem of mining at greater depths acquires increasing importance and demands the consideration .of a number of important factors, one of which is the greater earth-pressure and the consequent necessity of stronger support for the roof. Under the pillar-and-chamber system, almost exclusively followed in the Northen anthracite-field, the highest economy in mining is generally secured by leaving, on first mining, pillars only sufficient to support safely the overlying strata. As to the necessary size of such pillars, the opinions of mining experts are widely divergent. In establishing the width of chambers and pillars, the thickness of vein and its depth below the surface have received little consideration. For instance, it has been quite usual to work both overlying and underlying veins with the same width of chambers and pillars, when the lower vein was two and one-half times as thick, and twice as far below the surface, as the upper. In view of the generally-accepted theory that the crushing-strength of coal-pillars of the same base-area becomes less with increased height, it is probable, in this instance at least, that the moat economical mining has not been secured. This question of adequate pillar-support is economically less important down to about 800 ft. than at greater depths; and it is with reference to mining at these greater depths that the study of the subject here presented has been prompted. The necessity of leaving larger pillars, involving greater mining-costs per ton and also smaller yields per acre, is one of the troubles of deep working. To mine without leaving adequate pillar-supports will result, sooner or later, in a squeeze. Limited areas, it is true, have been mined at certain widths of

Jan 1, 1912

By Willard L. Cumings, Benjamin L. Miller

The Camaguey brown iron-ore deposit covers the top of Sari Felipe hill, the nearest point of which lies 14 miles NW. of the city of Camaguey. While there are several low flat-topped hills in the vicinity covered with a more or less continuous mantle of brown iron-ore, the deposit of San Felipe hill is the only one of any size and importance, and the name " San Belipe district" is proposed for the region. The deposit extends in a NW-SE. direction for a distance of about 10 miles, with an average width of 5 miles. The location is shown in Fig. 1, a sketch-map of the eastern part of Cuba. Fig. 2 is a map of the San Felipe district. 2. Description. The district is mentioned by Spencer,' who says: " The Cubitas iron-ore fields are situated from 12 to 15 miles north of Camagueg City, in the province of Camagueg.....Within an area measuring roughly 10 miles east and west and 4 miles north and south, there are several flat-topped mesas rising 300 to 400 ft. above the level of an almost featureless plain which extends for many miles in all directions except toward the north." With the exception of the discrepancy in his statements .as to the distance from Camaguey and the area of the hill, which is over 50 sq. miles, his description is a very good one. Kemp2 has the following to say of ores in Camaguey Province:

Jan 1, 1912

By Persifor Frazer

A classification of natural objects is usually based either upon some fundamental and permanent attribute of the thing itself (as in the case of scientific classifications), or it embraces one or more generalizations convenient for use in ordinary life. Thus, it suffices for the statistician to know that so many tons of fish are annually taken by our fishermen, and that they realize so many thousands of dollars, whereas to the student of natural history the anatomy, habits, and relationships of the animals are of chief interest, as settling their respective places in the scale of animate nature. Many different classifications of coals have been attempted, as one would naturally anticipate from the immense extent of the coal trade, and the different localities whence the supply was derived. The English divisions were prevalent up to the date of the publication of the last geological survey of the State, except so far as they were modified by local designations. Indeed, Rogers' classifications made very little alteration in the English nomenclature, as may be seen by comparing the tables given below. To commence with the different kinds mentioned in Ure's Dictionary of Arts, Manufactures and Mines of 1845 : " 1. Cubical Coal.—Black, shining, compact, moderately hard and easily frangible. Comes out in rectangular masses, of which the

Jan 1, 1879

By S. Arthur Krom

Recent experiments indicate that the usual type of concen-trating-table is not only poorly adapted to produce the desired results, but also is based upon an incorrect principle, namely, the use of riffles to perform the work of stratifying the various minerals. We have heard a good deal about riffles for concentratiug-tables; exhaustive experiments have been made to discover the proper form of riffle, or to prove the superiority of this or that form; disputes and patent-litigation have arisen over the matter of riffles, and thus marly have been led to believe that the riffle is the saving-device upon which the process of concentration depends. In the present paper it is proposed to show that the riffle is greatly overrated as to the part it performs in the concentration of minerals, and that, in the near future, it may possibly be eliminated entirely from that process. The experiments in question have shown that the troublesome riffle can be considered of secondary importance at the most, and should be so classed in the construction of a concen-trating-table built upon the right lines. The action of any form of riffle on a concentrating-table is such as to upset and retard the process of settling and stratifying the various minerals on the table-deck. From the deck of a riffled table no concentrates can be delivered until the deck is " bedded," that is, until a suffcient amount of metallic values has been fed to the table to spread over a large portion of the deck, forming a substratum of the heavier minerals. This substratum must be maintained by the feed within quite narrow limits, and directly proportional to the rate of discharge from the table, in order that the bed shall not be lost. On the other hand, the riffles having a very limited carrying-capacity, considerable care must be taken not to overfeed a riffled table, in which case the table proceeds, in mill parlance, to rob itself. As soon as the space between the

Jan 1, 1912

By K. A. Pauly

Compressed air has been and is still very extensively used in connection with mining-operations, but its application in the past has been almost entirely confined to supplying power to underground machinery. Its introduction was due to the difficulty of taking care of the steam which is exhausted underground, rather than to any advantage in efficiency to be gained by its use. The ease with which electric power may be carried to the remotest parts of the mine and the high efficiency of the electric motor have long been appreciated by mine-operators, and electric power is now extensively used underground in the more recent developments, while many of the compressed-air engines in the older workings are being rapidly replaced by electric motors. Recently, however, it has been suggested to use compressed air for driving the large shaft-hoists, the air for the engines being supplied by electrically-driven compressors, and an installation of this character is being erected at Butte, Mont. It is the object of this paper to compare the compressed-air system of hoisting with the various electrical systems, from the stand-points of first-cost and cost of operation. However, before entering into a discussion of the various systems, it will be well to consider briefly the conditions affecting the choice of a system of hoisting in which electricity is the ultimate source of power. The power required by a mine-hoist is extremely intermittent and fluctuates between very wide limits, the all-day average consumption of power not exceeding from 5 to 15 per cent. of the maximum demand during hoisting. The cost of supplying power for such a fluctuating load is necessarily higher than that for supplying an equal amount of

Jan 1, 1912

By Dwight E. Woodbridge

DuriNg April, Max, and June, 1910, I was in charge of an examination of the greater part of the Moa iron-ore area in Oriente Province, Cuba, on the north coast, near the east end of the island. My instructions, on arrival at the properties, were to check former estimates of tonnages and grades, and to re-examine the ore comprised in claims covering 44,727 acres. This work included the running of lines dividing the properties into co-ordinate planes, the boring of many thousand feet of holes spaced at the intersections of these co-ordinates, the taking of samples of the ore penetrated, the analysis of these samples for their various constituent minerals, and the determination of the results as to tonnages, depths, and grades, both for individual properties and for the entire group. Each section of every one of the thousand holes drilled was to be compensated for depth and grade with every other, a series of simple arithmetical calculations of no slight magnitude, the mere mechanical labor of which consumed much time, but finally resulted in giving a complete average of all the essential facts for the entire area of 18,000 hectares, Had it not been for the more than willing, active, and able co-operation of the officers of the Spanish-American Iron Co., from Charles F. Rand, President, and Jennings S. Cox, General .Manager, down to the most humble water-carrier, the work would have consumed far more time than it did. The lands thus systematically explored by me were comprised in the following denouncements: Punta Gorda, Yaminiguey, Baracoa secunda, Sagua, Moa, Yajrumaje, Lirio, and Cabanas, all of which were massed as the Moa group, so called, and cover an area of 13,832 hectares, or 34,179 acres. Some 10,000 acres additional to this was included in neighboring properties, lying between Moa and the east end of the island, the Buena Vista,

Jan 1, 1912