Senator MORGAN. It flows the other way? Mr. WALLACE. It goes the other way, and the water stays in your cut. The only extra expense that that will be to you, if you leave the barriers in, will be the fact that you will have to pump water out of that excavation, and the extra expense will be due to pumping that water out. It is just the same as if you were working in a cofferdam. Senator MORGAN. Now, working from the top to the bottom, after you got the different benches worked out and the material cut away to the width you wanted it, you would dispense with these shovels as you worked down? Mr. WALLACE. Yes, sir. Senator MORGAN. And finally you would get down to four? Senator MORGAN. And those four shovels will have to do all of the work except the breasting? Mr. WALLACE. Yes. Senator MORGAN. From mean sea level down to 40 feet below? Mr. WALLACE. Yes. That is, there are practically two furrows that are cut through where you will only have four of them at the last. Senator MORGAN. Yes. You do not expect to employ more than four shovels in the bottom of the prism of the canal? Mr. WALLACE. No. It is just as if you were running a gang plow through there that had four plows to it, and then you followed that with four other plows to dig it a little deeper. Senator MORGAN. If you worked from the bottom to the top you could have all the shovels that you employed, every one upon each bench, in operation at the same time, could you not? Mr. WALLACE. No; I do not follow you. If you had your whole canal opened out-that is, a narrow ditch from one end of your canal to the other, of the full depth-and could lay out terraces all the way along, you could work a shovel on each terrace, you understand, and you could do it all simultaneously; but that necessitates getting down first to the sea level clear through your cut, and by the time you get down there you have your work almost done. If you were going to build a canal that was 500 feet wide or a thousand feet wide, like Mr. Bunau-Varilla's "Straits of Panama," after you got down to sea-level you could work just as many shovels abreast as you had terraces, and do it all simultaneously, and you could widen that cut out to 500 or 1,000 feet with an enormous number of steam shovels, and the depth would not make any difference, because for every additional 25 feet in depth you would have a steam shovel. But the 200-foot width is so narrow that in order to get that face there is a time when you can work more shovels than you can at any other time, and that is about from one-third to one-half way down through the cut, and you would necessarily have to commence on top. But while you are doing this work on top, in the real work, there is no reason why you should not attack this excavation by bringing your dredged sections up to the foot of the cut on each side and working your dredges right up against this steep face and working in both directions from the sea. Senator MORGAN. When you say "dredges," do you mean "shovels?" Mr. WALLACE. No; I mean "dredges" in that case. In other words, while you are doing this dry cutting you are shoving your dredges in from the sea-that is, from La Boca toward the hill and from Colon toward the hill-and the supposition is that you will have your canal dug up to this point before you get this dirt all out; and you will have it dug up to this point before you get this dirt all out [indicating]. Now, while you are doing this work in the dry, as we call it, there is no reason why you should not attack this part, you understand, and push the sea-level sections just as far in toward the summit as you can get them. Senator MORGAN. Then your plan is to dredge from the sea in to, say, Obispo on one side? Mr. WALLACE. That is a question; just as far as you can do it economically. Senator MORGAN. I say, dredge in from the Bay of Limon Mr. WALLACE. If you found rock down in here that you could not dredge, then you would want to stop your dredging here, and probably you would have to take this out [indicating] in the dry. But the probabilities are that you could get up to possibly Obispo with your sealevel section. Senator MORGAN. There is no rock that would be encountered there that you could not dredge-by which I mean, of course, that you could blast it and haul it out, float it out, instead of hauling it out on a railroad? Mr. WALLACE. Yes, yes. Senator MORGAN. That is what I mean by dredging. That is a part of the dredging? Mr. WALLACE. Yes. Senator MORGAN. Now, if I understand it, you would start in the Bay of Limon and dredge up to, say, Obispo; then you would start on the other side in the Bay of Panama and dredge up to Miraflores, or wherever it is, there. Then, if I understand it, you would continue to take out all of the stone lying below the sea level to the bottom of the prism of the canal by this dredging process? Mr. WALLACE. No; only up to those points [indicating]. All of the material that I could remove by what we call dry excavation between Pedro Miguel, say, and Obispo, I would prefer to remove in that way, because you can do it cheaper. Senator MORGAN. Cheaper than you can by hauling it out on boats? Mr. WALLACE. Yes; that is, I mean, you can blast it and mine it cheaper in the dry than you can in the wet. Senator MORGAN. But you have to mine it in the wet when you get down 40 feet below sea level, have you not? Mr. WALLACE. No. Senator MORGAN. How do you manage to avoid that? Mr. WALLACE. You leave barriers of the natural rock at each end of your cut, and then go down in between those barriers and excavate it; and then, after you get your canal section cut out, you cut away these barriers and let your water in, so that it will be a natural cofferdam. Senator MORGAN. With an 18-foot annual rainfall, and water sluicing down from these heights, you would find that ditch full of water, would you not? Mr. WALLACE. Oh, no, sir; because you can divide it up into sections and pump it out, and you can push that work in the dry season for four or five months of the year, when you have practically no rainfall there at all. Senator MORGAN. Yes; and in the wet season? Mr. WALLACE. In the wet season you have it; but in my own experience I have pumped out cofferdams that had water from 10 to 15 feet deep, 300 feet wide, and a quarter of a mile long, in twenty-four hours. The rainfall at Culebra for the year that I was down there was 75 inches that is, for the entire year; and of course when you get down Senator MORGAN. How much was it in the wet season? Mr. WALLACE. That was in the wet season and the dry-the whole year. Senator MORGAN. It all fell in the wet season, did it not? Mr. WALLACE. Practically. We had four months when it was comparatively dry. Senator MORGAN. Yes. Mr. WALLACE. Now, what any prudent man would do would be to concentrate his work and try to do as much of it as he could in the dry season. Senator MORGAN. That is the point exactly. Mr. WALLACE. Undoubtedly he would. But the reason the advisory board added to that and made the unit price $1.50 per cubic yard was to give an amount that would justify pumping that water out, and with the powerful pumps that we have nowadays you could pump the full capacity of the Chagres River at low water out of that cut if you had to. Senator MORGAN. Then you would take out Mr. WALLACE. Now, the only reason, Senator Morgan, that I suggest that plan is because that would be a little cheaper than to excavate that rock under the water. Senator MORGAN. You mean by what is called the dredging process? Mr. WALLACE. Yes. That is, you can blast it cheaper in the dry than you can under water, because you can space your holes better, you can do your drilling better, you can see the character of your rock and you can get around it and over it, and I presume that you could possibly save about a dollar a yard on doing this work in the dry rather than doing it in the wet. Senator MORGAN. These heavy steam shovels require a strong track under them, do they not, and a well-ballasted one? Mr. WALLACE. Yes; but the material in that cut, after you get below an elevation of about 190 or 200 feet, after you get below the clay, will stand any weight you want to put on it. The only trouble that I had down there was that I upset one of these big steam shovels, because I got it up on the side of a hill in this sliding clay, and a very hard rain came up unexpectedly; the shovel was standing over a place in the ground where there was a subterranean stream of water that ran on top of the hard material under this clay, and there was about 8 or 10 feet of clay on top, and a slide came down, and the clay ran away from under the stream on one side that the shovel was standing on, and the shovel tipped over. But that was the only accident of that kind that I had while I was down there. Senator MORGAN. As you push these shovels against an embankment you cut in front of the shovel? The cutting is done in front of the shovel? Mr. WALLACE. Yes, sir. Senator MORGAN. And then you load it onto a car? Mr. WALLACE. Yes, sir. Senator MORGAN. Back of the shovel? Mr. WALLACE. Right alongside. The idea is to Senator MORGAN. Alongside; so you have to have a track for the shovel and a track for the car? Mr. WALLACE. You have to have a track for the shovel. Mr. WALLACE. Yes. Now, the track should be along on this bench here [indicating]. The shovels would be on the bench parallel to the track, against the face, and they would work a piece about 30 feet wide and about 20 feet high, and then the material would be blasted ahead of the shovel, and the shovel would work the stuff up just like you would take it up with a shovel by hand and put it over on the cars that would be parallel to it. Senator MORGAN. Yes; I understand that now. Therefore, you have to improvise a track as your shovel advances toward the embankment you are cutting in? Mr. WALLACE. Yes, sir. Senator MORGAN. And that is always in loose earth, is it not; and comparatively uncertain? Mr. WALLACE. Oh, no, sir. Below 200 feet there is no trouble at all with that; and we had no trouble whatever, all the time I was down there, in maintaining our working tracks under our shovels. The trouble we had with our tracks was with our running tracks out on our spoil dumps, where we had to put in sharp curves and frogs and switches, and where the equipment was rigid, so that it would not go around the curves, and the track would settle because we did not have any material to ballast it with, and our trains would go off the track. Senator MORGAN. When you got down to digging at 40 feet below sea level in these compartments we speak of, and blasting out the stuff, you could not use shovels there, could you? Mr. WALLACE. Yes, sir. Senator MORGAN. By putting them down on a level with the bottom? Mr. WALLACE. Oh, yes; they would go right down on a level with the bottom. That is all hard material down in there. Senator MORGAN. If you could use them when you got down that deep, why could you not use them before you got down that deep, by putting your shovel against this breast of rock? Mr. WALLACE. We can; only it is not safe to work against a breast of rock that is more than about so high. Senator MORGAN. It is not safe? and Mr. WALLACE. It is not safe. You are liable to undermine it, you are liable to have slides, and it will come down and bury your shovels up. In other words, if you were working your shovels in that way, you would be working in what we call a through cutting. The objection to that is this: That you can not get your cars ahead of your shovel in order to load your stuff into them; you can only load one car at a time, and then you have got to take that car out and put another one in. Now, the reason I wanted to get all these terraces clear through the cut and then start and cut one out and put it on a track, and then another one, was so that they would get the cars like this-say this was the face we were working against; the empty cars could be brought forward on that terrace and switched back on this, and could be fed right in continuously to the shovel, so that the cars would only have to be set at the shovels during the noon hours and the night and morning hours, and the shovels would never have to stop loading cars. Senator MORGAN. The point I am trying to develop is just this-that as you go deeper into this cut, until you get to the bottom of the prism of the canal, you have to give up shovels on each side of the cut and reduce the number of working shovels, until finally you get down to four in the bottom of the canal? Mr. WALLACE. No; not necessarily, Mr. Senator. For about three years your shovels will be put in in increasing numbers, because you will be developing new terraces. Then there will be several years that you can work the same number, and then you will work a decreasing number of shovels. Senator MORGAN. Yes. Mr. WALLACE. The essence of the whole matter is how to arrange that work so that you can work the greatest number of excavating units simultaneously at the fullest capacity per unit. In other words, if you can work ten shovels in each half mile and handle a thousand yards per shovel, you will make better progress than if you used forty shovels and were only getting 100 yards a day out of a shovel. So it is necessary to arrange your shovel plan so that your feed can be regularly and properly supplied to them, so that the operation will be continuous. Senator MORGAN. Much has been said some time back, and even down almost to the present moment, about night work on the canal. Could you conduct night work on this shovel system? Mr. WALLACE. I did not, but I could have conducted night work, and I think night work could be conducted more favorably on the Isthmus than it could be in the States. Senator MORGAN. Why? Mr. WALLACE. The temperature is more pleasant to work in there at night, and you can work the year round at night; and, properly lighted, there is no reason in the world why you can not work at night. At least, I know of none. Senator MORGAN. I suppose you really mean to say that you can do night work better than you can do day work in that locality? Mr. WALLACE. In that locality; but on the other hand, as I said a while ago, in the States I have never been able to get the same rate of efficiency out of night work that I have out of day work. One reason has been that the works have not been sufficiently lighted, and the laborers are more apt to shirk; they can get in the shadow and can not be watched as well as they can in the daytime. Senator MORGAN. So far as I am concerned, I shall have to drop this interesting view of the subject. It is very interesting to me, because it is very instructive. It is something that I wanted information about, and I suppose the balance of the committee would like it; but I want to ask you some other questions and then let other gentlemen go into this matter. |