room, the professors' room, and two rooms for storage and apparatus. Besides, two large rooms in the basement of the new wing will soon be fitted up for assaying and industrial chemistry. Until the present accommodations are crowded, the large room, 43 by 41 feet, on the first floor of the large building, will be appropriated to the State geological cabinet. Students who propose to become professional chemists will spend almost their entire time during their third and fourth years in the laboratories. This institution is the headquarters of the Missouri State geological survey. CHAPTER XX. THE BURLEIGH DRILL. Since the preceding pages contain (see chapter on California) a tolerably full account of the late operations of the diamond drill, it is but fair that some attention should be given in this report to its principal competitor, the Burleigh, now the most prominent representative* of the percussion machine-drills. In point of fact the Burleigh drill has never been successfully pushed in the West. One of them is about to be introduced at the Yellow Jacket mine, and another has been, it is said, contracted for by the Sutro Tunnel Company. But their actual use is confined at present to quarrying and tunneling operations in the East, and in mining, so far as I know, to the Lake Superior region. I give, as the best statement of the performances of the machine, the following extracts from a letter addressed to me at my request by Mr. H. A. Willis, of Fitchburgh, Massachusetts, the treasurer of the Burleigh Rock-Drill Company: We have not much to add to what has heretofore been published in regard to our machinery, except to state that time has fully proved the value of the machinery, and its economy over hand-work wherever any considerable amount of rock is to be removed. The drills have been introduced into nearly every State of the Union, and are at work in Canada and South America. They are also largely used in England, being manufactured at Manchester. They are just about being started in a tunnel in Italy, and we are about shipping three of our largest compressors there to run them, as they have not yet made many compressors at Manchester, and are in immediate want of them. The Lake Superior copper mines are using them largely, the Copper Falls, Allouez, and Central Companies being already equipped, and the Calumet and Hecla Company awaiting at present our completion of their order for eighteen drills. These companies expect to do all their drilling by machinery. We inclose a reprint of letter to London Mining Journal from Lake Superior, giving comparisions of hand and machine labor; also, a copy of Mr. Steele's article on Nesquehoning tunnel; also, letters of Messrs. Shanly & Co., showing the value of the machinery at Hoosac tunnel. With these data you will be able to say something about the machinery. You can use either or all of the cuts now in your possession to illustrate with, if desired. I would suggest that the cut you had engraved for us is the best representation of the drill as at present constructed, it having been entirely built over since your former report was made, and so strengthened that no important part of the machine ever breaks. Of course, the ratchets and springs wear out. Yours truly, H. A. WILLIS, Treasurer. HOOSAC-TUNNEL CONTRACT, North Adams, Massachusetts, February 23, 1872. DEAR SIR: I do not find a copy of the letter of 2d April, 1870, as published on page 19 of the Burleigh Rock-Drill Company's pamphlets, and which was written for our firm by my brother. I can, however, testify to the correctness of the facts stated in that letter. The compressors we have been using ("No. 2") have been doing their work very well, "driving from two to three tunnel-size machines" each. As respects, the difference in rapidity and cost between drilling in rock with these machines and by hand, we could not say without going into figures what it may actually be; but this we can say, that without the " Burleigh drills" we would not undertake such a work as the Hoosac tunnel on almost any terms. W. SHANLY, For F. Shanly & Co. Hon. GEO. E. TOWNE, President Burleigh Rock-Drill Company, Fitchburgh. The Gardner drill, a machine resembling the Burleigh, is in satisfactory use at various places in the East. I cannot enter into the merits of the controversy between the proprietors of these two machines as to the patent-right. HOOSAC-TUNNEL CONTRACT, North Adams, Massachusetts, February 26, 1872. GENTLEMEN: In reply to your letter of the 20th instant, asking some particulars of our experience in the use of the Burleigh rock-drill, the machines we have been using are those known as the "tunnel-drill," having, in the terms of your inquiry, "their operating-end made as axial continuation of the piston-rods." We have some sixty of these machines in service, and they have given great satisfaction, working under an atmospheric pressure of from 55 to 60 pounds on the square inch, and making upward of 200 strokes per minute. We estimate the saving in expense, as compared with hand-drilling, at about 33 per cent., and in point of time there is a gain of fully 50 per cent.; in other words, effecting a saving of at least five years in the finishing of the Hoosac tunnel. Yours, respectfully, Messrs. CROSBY & GOULD, &'c., &c., Boston, Massachusetts. F. SHANLY & CO. [From the London Morning Journal, November, 1871.] SIR: Regarding the introduction of drilling-machinery into mines as a very important subject, and as I happen to be familiar with the results obtained from the work. ing of the Burleigh drill, on Lake Superior-where, by the way, it is by no means common-perhaps you will allow me space for the accompanying remarks. Doering's machine was tried in Tincroft and in Dolcoath mines, Cornwall, and thrown out, I believe, because it would not pay. I was never fortunate enough to learn the results obtained from working it; but it seems to me that somebody ought to have been sufficiently interested in this machine to find out what work it did, as well as what work it could do, and make it public. I saw a statement made that the machine drifted a given number of feet more in a month than six good miners could do; but, as its use has been discontinued, I infer that it cost more to break the ground than by hand-labor. I was underground in this country with Mr. Nobel, when he was making efforts to introduce nitro-glycerine; he, of course, was praising the compound, and remarking on the success attending his endeavors to get it into use; but," said he, "I could not succeed in Cornwall-they are prejudiced there against everything new." I felt my "Cornish " get up, at the time, and was inclined to dispute the assertion made, but, on reflection, it seems to me that there is a deal of truth in what was said. I believe the putting in of the man-engine at Tresavean mine was due as much to the efforts of the Polytechnic Society as to those running the mine. One of the deepest and best-managed mines in the Camborne district was a long time seeing the propriety of using skips, and how many now stick to the kibble! Ten years ago the wheelbarrow was as common as the tram-wagon. I have yet to learn that it is gone out of fashion. It is only of late that any attention has been given to increasing the stamping duty in mines; and when Messrs. Harvey & Co. set up and tried the pneumatic stamps, in their very laudable efforts to reduce the cost of stamping, if I remember aright the tenor of the remarks made by the "astute" manager of a very rich tin mine was to the effect that "we will let somebody else try them, and in that way learn if they are a success." There is a difference in starting a drilling-machine in a mine, with the authorities interested in, or indifferent to, its success; the men commonly regard an innovation with disfavor; and I would defy any inventor to succeed in working a machine by Cornish miners if they considered it was against their interest that it should succeed, unless he personally supervised it, or had a competent person in his interest to do so. Cornishmen are good miners, and good mine managers-they ought to be-but they are just as apt as others to conclude that what they do not know is not worth knowing. I am not going to draw the inference from the foregoing that the Doering machine did not get a fair show, nor would I for a moment suppose that the authorities in the mines where it was tried had prejudged it; even if they had, they would exert no undue influence against it. Still, if they were not in favor of it, I would certainly venture the opinion that the Doering machine did not do its very best. I am ready, however, to drop the Doering as a failure, and will try to tell you what I know of the Burleigh drill. The first machine of the kind brought into the copper region of Lake Superior was tried at the Pewabic five years ago. The Red Jacket mine used one for a short time just afterward in sinking a perpendicular shaft from surface. The motive-power applied was steam in both instances. I cannot conceive that a hot-drilling machine could be a success. The next trial-and the first with air-compressors--was made at the Aztec mine, Ontonagon County; this was a disgraceful failure. The Central Mining Company next procured a Burleigh, about two years ago, to 85 work in an incline shaft which they have been sinking for several years. The said shaft is being sunk in the country 14 by 8 feet, at an angle of 300 from horizontal; this machine is still at work. In last year's report of the mine the mining captain stated that by the use of the drill they had increased the rate of sinking 50 per cent. This was the first machine of the kind I saw at work; and it very forcibly struck me that the machine could drill more ground in an hour than three of the best miners could in a day. After that at the Central mine had been working some months the Copper Falls Company decided on trying one on what they term the Ashbed, a lode of amygdaloidal character, varying in width from 7 to 10 feet, and dipping at an angle of 26 from horizontal. The lode is known here as a "stamps lode;" the proportion of copper contained therein is about 1 per cent. of mineral, or per cent. of ingotcopper. The copper varies in size from the finest particles to pieces of 1 pound weight; rarely larger. The lode forms an integral part of the formation; the over and underlying belts of trap protrude irregularly into it, consequently there is no regular or defined foot or hanging wall. Another feature is the almost entire absence of "slips," or "breast-heads." The ground cannot be called hard, but is "short" to "break," requiring more than ordinary care in planning holes. Four good men can drive from 18 to 23 feet per month in an ordinary-sized level; the same number can stope from 10 to 12 fathoms in the same time. For the past two years, instead of letting the stope to the miner per fathom, he has been paid so much per foot to drill holes, under the direction of a competent person. A more trying place for a drilling-machine cannot be found, the inclination of the lode being a serious disadvantage in carrying a wide breast on a level. After getting fairly under way, it was found that three men and one boy in a shift, or six men and two boys with the machine, could drift from 40 to 44 feet per month, carrying a breast 18 by 8 feet; this was doing the work of 16 men, but at no reduction of cost. It was then decided to try what could be effected by stoping; and after a carriage was constructed for the purpose, work was commenced. The carriage and machine weigh about 1 tons. To move them up over the foot-wall a pair of common blocks and a small crab-winch are used. The mode of working is to set the carriage in the level, and commence cutting in for a stope, which is carried toward the bottom of the level over the stope worked out, lower the carriage down, and commence another. In working this way less drilling is performed with the machine, because more time is occupied in moving it; but it pays best. Early this summer three drills were started, two No. 1 compressors supplying motive-power; these last cannot be relied on to do good duty without hinderances; very commonly the pressure of air being insufficient to work with. To obviate this, a No. 3 compressor has been set up and was started two weeks ago. This gives ample air to run three, or even four drills, going from 60 to 70 revolutions per minute. The gauge shows a pressure of from 45 to 55 pounds per inch, varying, of course, with the number of drills running at the time. Since starting this an increase of duty has been effected, as well as a material saving in fuel. I have been fortunate enough to obtain the results of last month's running with the three drills now in use; these figures may be taken as the result of running three machines, with two No. 1 compressors supplying air : No. 1 machine is the improved tunnel-drill; No. 2, the small machine, as constructed five years ago; No. 3 is same as No. 1, but was worked irregularly, frequent stoppages being necessary to blast. The timing an average day's work with No. 1 machine before and after starting the new compressor gave the following figures, (time is given in minutes.) Men leave the "dry" at 7 o'clock; quit work at 6 o'clock: The diameter of holes varies from 2 inches to 24 inches, none less than 2 inches.. The heaviest day's work, or rather the heaviest shift's work, performed so far has been the drilling of 13 holes, or 64 feet of ground. Some shifts, when the machine is employed in drilling "dry holes" in the back, only about half that amount of work is performed. Copper commonly offers a serious impediment to the drill; but for this it would be easy to drill 60 feet per shift on an average. In the day's work given above one hole required 67 minutes of drilling-time to sink it 5.5 feet deep, when, but for the presence of copper, the same work could have been done in 22 minutes. The rock broken in the mine last month was at the fourth level, by hand-drilling exclusively, at the fifth level by Nos. 1 and 2 machines, at the sixth level by No. 3 machine and hand-labor combined. The rock from each level is carefully reckoned; that from fourth level amounted to 1,035 tons, from fifth level 1,941 tons. This is sufficient to show comparisons regarding cost, which, at fourth level, was as follows: Drilling holes, 3,035.7 feet, at 26 cents.... Man in charge. Supply-Candles, 16 pounds, at 20 cents Fuse, 2,850 feet, at $10 Powder-cans, three, at 50 cents. Cost of breaking 1,035 tons of rock, at $1.035 per ton. The cost of running Nos. 1 and 2 machines at fifth level was as follows: $789 28 $854 28 3 20 184 00 28 50 1 50 217 20 1,071 48 |