Skip to main content

Search the Special Collections and Archives Portal

Interview with Wendell D. Weart, April 18, 2006


Download nts_000158.pdf (application/pdf; 229.51 KB)





Narrator affiliation: Geophysicist: Sandia National Laboratories

Digital ID


Physical Identifier



Weart, Wendell D. Interview, 2006 April 18. MS-00818. [Transcript]. Oral History Research Center, Special Collections and Archives, University Libraries, University of Nevada, Las Vegas. Las Vegas, Nevada.


This material is made available to facilitate private study, scholarship, or research. It may be protected by copyright, trademark, privacy, publicity rights, or other interests not owned by UNLV. Users are responsible for determining whether permissions are necessary from rights owners for any intended use and for obtaining all required permissions. Acknowledgement of the UNLV University Libraries is requested. For more information, please see the UNLV Special Collections policies on reproduction and use ( or contact us at

Standardized Rights Statement

Digital Provenance

Original archival records created digitally

Date Digitized



44 pages





Nevada Test Site Oral History Project University of Nevada, Las Vegas Interview with Wendell D. Weart April 18, 2006 Albuquerque, New Mexico Interview Conducted By Mary Palevsky © 2007 by UNLV Libraries Oral history is a method of collecting historical information through recorded interviews conducted by an interviewer/ researcher with an interviewee/ narrator who possesses firsthand knowledge of historically significant events. The goal is to create an archive which adds relevant material to the existing historical record. Oral history recordings and transcripts are primary source material and do not represent the final, verified, or complete narrative of the events under discussion. Rather, oral history is a spoken remembrance or dialogue, reflecting the interviewee’s memories, points of view and personal opinions about events in response to the interviewer’s specific questions. Oral history interviews document each interviewee’s personal engagement with the history in question. They are unique records, reflecting the particular meaning the interviewee draws from her/ his individual life experience. Produced by: The Nevada Test Site Oral History Project Departments of History and Sociology University of Nevada, Las Vegas, 89154- 5020 Director and Editor Mary Palevsky Principal Investigators Robert Futrell, Dept. of Sociology Andrew Kirk, Dept. of History The material in the Nevada Test Site Oral History Project archive is based upon work supported by the U. S. Dept. of Energy under award number DEFG52- 03NV99203 and the U. S. Dept. of Education under award number P116Z040093. Any opinions, findings, and conclusions or recommendations expressed in these recordings and transcripts are those of project participants— oral history interviewees and/ or oral history interviewers— and do not necessarily reflect the views of the U. S. Department of Energy or the U. S. Department of Education. UNLV Nevada Test Site Oral History Project 1 Interview with Wendell D. Weart April 18, 2006 Conducted by Mary Palevsky Table of Contents Introduction: birth in Brandon, Iowa ( 1932), education at Cornell College ( graduated 1953) and University of Wisconsin, work at Aberdeen Proving Grounds, Maryland 1 Participation on Tamalpais ( NTS, 1958) and seeing first of atmospheric nuclear test 2 Takes position as geophysicist with Sandia National Laboratories ( 1959), nuclear testing moratorium and work on near field ground motion studies on Gnome ( Plowshare) 3 The issue of decoupling and searching for areas in U. S. in which to do high- explosive shots 6 Work at NTS on Marshmallow ( 1962) and containment of underground line- of- sight tunnel shots ( including Cypress [ 1969] and Camphor [ 1971]) 8 Explanation of line- of- sight pipes, ground motion and radiant energy in underground nuclear detonations 11 Sandia’s development of closures for line- of- sight pipes 13 Description of post- shot reentry, block motion, and faults 14 Discussion of ground motion concerns: Las Vegas, NV, influence of Howard Hughes 17 Nuclear testing in Amchitka, AK ( Milrow and Cannikin [ 1971]) 21 Baneberry test at NTS venting ( 1970), chairs investigating panel re containment failure and creation of the Containment Evaluation Panel ( CEP) 27 Work on CEP ( 1970- 1975) 35 Work on WIPP ( 1975- present) 37 Early experiences at Nevada Test Site 38 Creation of WIPP 39 Views about necessity of the test program 41 Conclusion: final thoughts on ground motion studies and containment 42 UNLV Nevada Test Site Oral History Project 1 Interview with Wendell D. Weart April 18, 2006 in Albuquerque, New Mexico Conducted by Mary Palevsky [ 00: 00: 00] Begin Track 2, Disc 1. Mary Palevsky: Wendell Weart, thank you very much for meeting with me this afternoon, and if we could start by having you just give me your full name? Wendell Weart: My name is Wendell Weart, because my signature name is W. D. Weart, my middle initial is D. I was born in Brandon, Iowa in 1932, September 24, 1932, and went to Cornell College in Iowa, not to be confused with Cornell University, and got my bachelor’s degree in geology and mathematics at Cornell, and then went on to University of Wisconsin to get my Ph. D. in geophysics. I suppose the reason I got interested in earth sciences is largely due to the fact my brother, who was ten years older than I am, was a geologist, and I accompanied him on summer field trips as he gathered information for his thesis. So I became quite intrigued with the world of earth sciences, and as I went on I felt like I’d like to apply a little more of the physics to the interpretation of geology, and that’s why I went into geophysics. I graduated from Cornell College in, let’s see, 1953, entered the graduate school at University of Wisconsin, interrupted my graduate work to take a job at Aberdeen Proving Grounds in Maryland; worked there for about three years, and was just getting ready to return to the university to complete my thesis work when I got a letter from a gentleman at Sandia Laboratories, neither the gentleman nor the institution was I familiar with, asking me if I’d be interested in coming to work with them and they would help me finish up my thesis work and we’d go from there. So since the stipend they were offering sounded a lot better than the UNLV Nevada Test Site Oral History Project 2 fellowship I would’ve got at the university, and I was married and had children by then, I said sure, let’s look into it. Now when you went to Aberdeen, let me just interrupt you, were you in the service then or were you—? No, I was a civilian. I went out there to work on some earth science programs and air blast programs from large explosions, and interestingly enough, it was while I was at Aberdeen that I had my first exposure to the Nevada Test Site [ NTS]. I went out there in 1958 to do some work on an underground tunnel test. That got me started on my work in the tunnels at Nevada. Interesting. Which test was that? It was the Tamalpais event. It was a relatively small event but it gave me my first opportunity to look at some of the atmospheric tests that were still being conducted at that time, although I never had any personal involvement in any of the atmospheric tests, only in the underground. Well, I have to ask you then, what was your impression of seeing those atmospheric tests? Well, you know, I guess little boys like fireworks and firecrackers, and this was the biggest set of fireworks you could ever hope to see. Really exciting, because in those days, it was a little more free form than it turned out to be later with all the additional safety requirements, so you could go out and observe at observer posts, and even some of the large events, like the Sedan cratering shot. I was up on top of Rainier Mesa when that was detonated, which was quite a bit below the valley floor where the shot was. The shot went off, you could see the ground rise up and then the fireball break through, and then the cloud go up, and you got to wondering, is that cloud coming my way, because it was so high above you. Of course, it didn’t. But now, you know, I say “ now,” I haven’t worked out there actively on the test program since about 1975, but in the later years it became much more safety conscious and that was the kind of thing that you’d never UNLV Nevada Test Site Oral History Project 3 consider allowing people to do. No one went into the forward area when they were conducting a test there. So it was quite a different perspective than people later in the program got of these [ 00: 05: 00] testing operations. But while I was out there with the Aberdeen Proving Grounds group, Ballistics Research Laboratories, I had an occasion to talk with a lot of the other people who were doing tests out there; found out later, in fact, that one of the people I had met and who offered to let us use some of his electrical cable was one of the people at Sandia in the group that I ended up work with. That gentleman was named Bill [ William] Parret and he’s passed away now. But it was interesting how my career started there, and then I continued on after I came to Sandia. Thanks for that. So you got this offer for Sandia to what? They would support you in finishing your dissertation? Yes, they did support me as I finished my dissertation, which had to do with seismic wave propagation. And the reason I went there, they were interested in having a geophysicist— and there weren’t too many of our breed at the time, not too many graduate schools teaching geophysics and seismology— at about that time our country was engaged in discussions with the Russians about a test ban treaty, and in particular an atmospheric test ban, which meant all the tests would be underground. Well, if the tests are underground, it’s the ground motion that’s generated from those that’s one of the primary mechanisms by which you can detect a test, and so we were naturally very interested in learning more about this field of ground motion, seismology, and so I was hired at Sandia to look into that. Now what was Sandia like in those days? That’s still in the first decade of its existence, I guess. Well, yes, I joined Sandia in 1959, and Sandia was a little over a dozen years old by then. But Sandia was a very burgeoning laboratory then. We were rapidly hiring people because we were UNLV Nevada Test Site Oral History Project 4 building up very rapidly, and that was an interesting period of time in a sense that a lot of things seemed to be going on simultaneously. Shortly after I arrived at Sandia, there was a moratorium on testing, and all testing ceased, but during that time work didn’t stop. It allowed me a chance to do my thesis because otherwise I’m not sure I would’ve had the freedom to do that with all the other things going on. But anyway I did complete my thesis, and one of my first big underground tests on which I was directly involved was Project Gnome, which was very soon after the Russians abrogated the moratorium. I was the scientific person responsible for the near field ground motion studies on Project Gnome, so I spent a lot of time down there on that event and on the subsequent reentry, again because of my geologic background, to look into that event and try and figure out exactly what went on underground, because it didn’t behave as we had expected. Oh really. So tell me a little more about that. Well, let me go back to Rainier, which was perhaps the first of the underground contained events, and on that event the containment concept was to use a buttonhook, which would cause the tunnel to be slammed closed opposite the detonation before the shock could come around the buttonhook in the tunnel and squirt on down the drift. That was the same concept that was used on Gnome, but it didn’t work there. It did vent. It got loose into the tunnel and eventually after, oh, three, four minutes, it circumvented the large plugs that were at the base of the shaft and started to ooze steam up the shaft and out into the atmosphere. And since it worked once but it didn’t work this time, we wanted to see if we could understand what went wrong. And in fact, I think we did develop a reasonable explanation because the Gnome setting was in a stratified, a [ 00: 10: 00] bedded geology, and as the pressure in the cavity from the detonation caused the cavity to grow, the gases in the cavity opened up these bedding planes which were horizontal and UNLV Nevada Test Site Oral History Project 5 allowed the gas to squirt right out into the tunnel. So even though there was a line- of- sight in the drift, it was not the line- of- sight that contributed to the venting; it was the geology that was responsible for the venting. Now Gnome was in New Mexico, right? Yes. And what was the reason for it being there? Well, it was a Plowshare event. It was the first of the big Plowshare tests and it had several purposes. One was to see if they could use the heat that was deposited in the salt, resulting in a molten pool of salt, extract that heat by pumping water down, turning it into steam, going up a pipe, and driving a turbine to make electricity. There were some other purposes. One was a Vela Uniform- type purpose, and that was to find out what kind of seismic waves and seismic signature would be generated by having a detonation in another kind of rock. This was in halite, which is just table salt, and all of our experience in Nevada was in alluvium or volcanic tuff. So that was another purpose of Gnome. And there were still a couple of other scientific purposes. Los Alamos had what is called a neutron wheel at end of this long horizontal line- of- sight pipe. It had heavy metal foils on the rim and it spun at a very high rate of speed. And when the shot went off, the neutrons that were generated came down this vacuum pipe and they would hit the foils at different points as this rapidly- spinning wheel went around, and that allowed then these foils to be activated by the neutrons. People then would go back down quickly and recover these and measure the neutron cross- sections. And still another of the purposes was to see if the copious number of neutrons generated by this event could be used to create much higher atomic number elements, which they would promptly capture through a vertical line- of- sight pipe and get it to the surface and analyze. UNLV Nevada Test Site Oral History Project 6 Well, some of these experiments worked perfectly, some worked partially, and some didn’t work at all. The fact that it vented into the drift complicated the recovery of the heavy metal foils, but they eventually did get in and recover some information on that. The Plowshare purpose to look at heat generation and steam power generation did not work because the roof of the cavity fell in and quenched this molten salt, and so there was no pool of molten salt to access when the water was pumped down. The seismic experiment worked well. The ground motion studies were successful, and in fact we found that the seismic coupling in salt was much more efficient, much more effective than from the rocks at the Nevada Test Site, so we learned that if you were to shoot a shot in salt, a much smaller shot could be detected than if it were shot in alluvium in Nevada. But then people got to thinking, and the theorists put on their thinking caps and they said, but what if we mined a big cavity in salt and put the shot in that? Called decoupling. And in fact there were shots to investigate that in salt domes down in Hattiesburg [ Mississippi] and we determined in fact that yes, shots in cavities would decouple the amount of seismic energy that goes out to the far field. So anyway, I sort of got beyond my story, which was that was my initial exposure to underground testing, the Gnome event. Right. Because I did actually quite recently talk to a Holmes and Narver engineer who worked on the engineering of Gnome, so thank you for the detail because that fills in some pieces of that story. So that was the first event that you worked on, then. Yes, and in the meantime, during the moratorium, one of the interesting things I got to do with [ 00: 15: 00] some of my fellows from Sandia was to go around the country looking for various rock types in which to detonate high explosive shots, because of this concern about how do different rock types couple energy. So I got to tour some beautiful scenery in the West and look UNLV Nevada Test Site Oral History Project 7 at some exciting sites. But as it turned out, before those things ever took place, the moratorium was breached and we went back to testing and that took people’s time. We did continue to wonder about the behavior in other types of rock, and Project Shoal on which I was the science advisor was in granite just east of Fallon, Nevada; that gave us a point on how seismic energies propagated out from a granite- type rock, salt from Gnome, and then the tuff and alluvium from Nevada. Now I’m sure there are various reasons that you want to know these things, but am I understanding correctly that one of the primary reasons is for detection of Soviet tests, how things would behave in this rock, or just the science itself of how the explosions behaved? Well, at the time, the interest was in how confident would we be in detecting Soviet shots if they were shot in different types of rock. Turns out that we had a fairly advantageous situation in Nevada because alluvium soaks up so much of the energy, not nearly as much gets out in seismic waves. But of course, if other countries looked for sites of a similar nature or decoupled their shots, they might also be able to hide their nuclear events more easily. But that was the original impetus. Later on, we had an interest of our own in this country as we started to shoot larger and larger shots, worrying about whether the energy that was propagated to distant sites like Las Vegas from the test site, would we cause more severe ground motion and therefore more severe building motions in different types of media? What was the best location and type of rock to shoot in? Not that we had a lot of choice in Nevada. We had alluvium, but mostly the alluvium, because of its thickness, could only accommodate smaller events, and for the bigger events you had to go deeper or further away, like Pahute Mesa, which is volcanic tuff. But we were quite concerned in being sure that we understood how the energy would couple into these distant seismic waves. That of course was one of the reasons we did the study looking for the Faultless UNLV Nevada Test Site Oral History Project 8 site, to see if we could use a site further away from Las Vegas to shoot large- yield events. So we did the Faultless event in an area that we had selected that we thought would be advantageous, and measured the ground motion very thoroughly with seismometers, and then from that predicted what size event we could accommodate without causing some concern for high- rise buildings in Las Vegas. Well, as it turns out, they decided that for events of a megaton and more, probably should get out of Nevada completely, and that’s why they ended up in Amchitka [ Alaska] for those two really large shots we did. Right, but there were megaton shots in Nevada, no? There was one or two. I think Boxcar was one. But we found that from those events we were getting a lot of complaints and a lot of architectural damage to structures in Las Vegas. As time went on and people became more aware of this, we began to get more and more complaints, and finally I think the AEC [ Atomic Energy Commission] or Department of Energy [ DOE] or whatever you want to call them became concerned that they couldn’t even continue 1 megaton- size events in Nevada without getting undue complaints. But there were one or two, I think. Benham was one. But there weren’t too many of that size, and when we started to go above a megaton, [ 00: 20: 00] then we went to Amchitka. Now I want to talk to you about that, but before, a little back on the timeline, just because I was reading your thing [ profile and interview exerpts] from Caging the Dragon. Can you talk to me a little bit about Marshmallow and the work you did on that? Yes. Marshmallow was a shot that had been detonated in a tunnel with a horizontal line- of- sight, one of the first of its kind, and it almost contained, very little seepage of radioactivity, so it was regarded as a success, and it was different than the other shots like Rainier because there was no buttonhook, just a straight line- of- sight pipe in a tunnel. So again, my geologic background was UNLV Nevada Test Site Oral History Project 9 useful to me and I headed up a program to look at the reentry of the Marshmallow event. The reentry occurred, oh, a year or two after, and the report written on it was a classified report. I don’t know what’s been classified and declassified nowadays, so I won’t say anymore about it, but there was a report prepared on that. I’ll see if I can get some declassified version of it from the archive. And that was what really directed our thinking in the early days about how to do the containment on underground line- of- sight tunnel shots. We did have some that were successful after that and some that weren’t very successful. Most of the tunnel shots were DoD [ Department of Defense] shots, but Sandia in the early days did a lot of the containment design on those. Sandia had two shots of their own which they were responsible for up in the mesa, Cypress and Camphor. Cypress was well contained, no releases. Camphor tried to push the envelope a little bit too much. It was a much more rapidly diverging line- of- sight pipe, the mechanical closures were closer. It did not work as well. Not a whole lot got out to the atmosphere, but a lot got out to where the experiments were. It made it very difficult to retrieve and recover experiments. Now so I understand the organizational issues, you’ve got DoD doing these shots and then the labs, Los Alamos or [ Lawrence] Livermore [ National Laboratory, LLNL] usually are designing them, but in the case of Camphor and Cypress, Sandia scientists— Well, the DoD shots were designed, they were done primarily for phenomenology, experimental results on structures or components you’d put in there. They were not weapons development. So the Department of Defense would say what they needed and what they were going to expose in the line- of- sight pipes, then the laboratory, one or the other laboratories, would provide the device, the nuclear component. And in the early days Sandia did a lot of the containment design, and then phased out of that and DoD used their own consultants and contractors, but because UNLV Nevada Test Site Oral History Project 10 everyone was really involved in this endeavor to try and provide containment, all of the labs were sort of involved and we were a small community. Well, each lab may have had a dozen, two dozen people, and after Baneberry they got even bigger, but before there were a relatively small number of people who would all get together and trade ideas on how to do containment. Everyone thought they knew the best way, and when you got them all together later on, we decided that maybe none of us knew what it really was that was basically responsible for containment. But there were a lot of ideas that developed over time that seemed to make sense and seemed to work and so people would utilize those again and again and often had success but [ 00: 25: 00] occasionally still had failures even then. I remember reading when I was doing the preparation for this interview a comment you made, I think in response to a [ James E.] Carothers question [ in Caging the Dragon] and we can look at it if I don’t get it right, the notion that if it worked you thought you knew why it worked and then you had something that should have apparently worked the same way and it didn’t, and only by that happening did you realize maybe you didn’t understand why it worked. That’s right. We of course got to the point as our ability to do extensive calculations, do better theoretical evaluations improved, that we tried to use that ability to calculate how these things would behave. But of course Mother Nature being what it is, they sometimes fooled you. As a layperson and an outsider, what is just so interesting to me is that you’ve got these— although it says in this book [ DOE/ NVOO- 209] I know this book is not completely accurate— that Marshmallow was a relatively small shot, but that you’ve got these tremendous amounts of energy underground in non- uniform, geologic environment, that there must be so many variables to what would happen— UNLV Nevada Test Site Oral History Project 11 Well, there are, and we did come to a conclusion that the geologic setting can make quite a bit of difference, and in the later years it led people to avoid certain kinds of geology for certain types of shots. We learned that big shots are sometimes easier to contain than little shots because you use the energy to help you do containment, and so the more energy you have, providing you recognize the scaling effects, the more energy you have, perhaps the easier it is to contain. Yes, that was something I really don’t think I quite fully understand, this whole notion that the energy itself— is it the ground motion energy or is it not that actually helps seal things? Maybe you can tell me. Yes. Now in talking about line- of- sight pipes, because you have this big open line- of- sight pipe pointing right at the device, and so you naturally would think that the energy of the bomb going right down that pipe would get down to the end and would just keep flowing down and defeat everything. What we found that we could do is first by using the radiant energy of the explosion itself, cause a very fast- acting seal right at the beginning of the line- of- sight pipe, what we call the front end sometimes; and we designed them with certain geometries and certain materials so that as the radiant energy from the bomb flowed around this, it would cause it to implode and squeeze closed. And then, if you could do that successfully at the very beginning, you know, microseconds, then the ground motion which is generated by the explosion starts out by being much faster. It’s a hydrodynamic shock wave that travels in the ground and it’s much faster than the seismic energy that travels off to great distances, and that ground motion would then get out and squeeze the pipe as it went along, squeezing it closed right in front of the energy that’s trying to come down the pipe; what you have then is a race between this ground motion trying to squeeze the pipe closed and the energy trying to come down the pipe. And if you do things right, we think you can succeed and nothing gets out. If you don’t do things right, maybe because of UNLV Nevada Test Site Oral History Project 12 the type of geology you’re in, that hydrodynamic shock doesn’t develop to the extent that it would in another rock type and you lose the race and you don’t seal off as well as you’d hoped. So that’s why geology that Nature provides is important, but we also think that there are design things you can do to help you a lot with this problem. And if you lose the race, then that radiant energy and the radiation can do bad things to your— Well, yes, what happens then is as this cavity is forming, it has tremendously high gas pressures in it, and if you can’t close that pipe off, these high gas pressures will flow down that open pipe [ 00: 30: 00] and it’s just like a plunger, and it will take everything with it. And we’ve reentered tunnels, experiments, where a hundred, two hundred, three hundred feet of massive steel pipe will be all balled up way out here by the force of that flow. So it starts out as radiant energy but the thing that continues the push are the high- pressure gases in the cavity. So all the time, you’re trying to get the odds in your favor in this race between the closure of the line- of- sight pipe, using the energy generated by the device itself, from the energy that’s trying to flow directly down the pipe. Right. But you’re saying that initial ground motion energy is different than this distant seismic energy. Yes, it’s much faster. It travels much faster through the ground because the pressures are so high. It’s just like a supersonic shock wave in air, when you get high enough pressures it travels faster, and then as it dies down to lower amplitudes, it travels at the speed of sound and in air. Well, in the earthen material, the speed in the various rock types, the seismic velocity, may range anywhere from a few thousand feet per second to twenty thousand feet per second. But this hydrodynamic shock very close in is many times faster than that, and that’s what enables you to run ahead of this other energy and close off the pipe in front of it. UNLV Nevada Test Site Oral History Project 13 Interesting. Well then, the other issue you raised is this whole development of all these different closures along the way? Yes. Now is it that you were saying that Sandia was—? Yes, Sandia, for the Department of Defense, was given the responsibility of developing these fast- acting closures, which are mechanical devices actuated either explosively or with very high gas pressure reservoirs, that would drive very massive doors across the line- of- sight. Those were put into the line- of- sight to close it off at distances of a few hundred feet, because even though they’re very fast, if you put them too close, they weren’t fast enough to beat this energy, and if you didn’t beat it, they would never close. So that’s what we did, is we tried to develop these mechanical closures. There were also other kinds of closures that were used from time to time, which used the energy of the shock wave itself by making the pipe heavier on one side than another, so that when it tried to close off, instead of doing it symmetrically, it would do it asymmetrically and maybe close it off better. Or one of the labs came up with a design to wrap a spiral band of metal around the pipe to help it close in a non- symmetric way. But these were sort of fine- tuning on the basic principle of using the ground shock to close things off. But those doors obviously were able to— In many events, when we reentered, I don’t know in the later years if they reentered as many of these events but in the beginning we reentered almost every one, the ones that succeeded as well as the ones that failed, and we found that indeed these fast closures on the ones that succeeded were essential to stopping the fragments from coming down and ruining experiments. But we found on others, if they didn’t close before the main energy got there, then they weren’t successful and stuff just extruded right through them and on down the pipe. UNLV Nevada Test Site Oral History Project 14 Now when you say “ reentry,” did you physically go in on these reentry things or—? Yes. What was that like? Well, it was uncomfortable, particularly for me wearing glasses because you had to go in wearing full face mask because of the radiation. But it was extremely interesting because it’s hard to imagine and it’s hard to really describe to people the visual evidence of the amount of energy that these nuclear devices going off releases. It can move large blocks of the mountain, [ 00: 35: 00] and some people feel that in fact containment success or failure may be due to block motion, where the blocks slide across the tunnel. In many cases we found that motion on preexisting faults just offset the drift, and closed it off by putting a new piece of the mountain in front of the fault. So it gave you a real respect for the energy in these devices and what’s released. That’s interesting, and I want to ask you more about how that procedure went, because you spoke about having seen these atmospheric tests, and one of the things that people talk about impressing upon them is the huge amounts of energy, but somehow, for the layperson again, everything sort of disappears once it goes underground, but you’re saying that you see evidence as a geologist of the— Yes, while the above- ground tests that I saw— and I didn’t see any of the real big ones, but the small ones I saw— they were visually impressive, but they didn’t give me anything I could physically get my hands around, my mind around, to give me a firsthand impression of the energy. But when I would go back in a tunnel and see what happened to these massive structures that we had put in there, and to see how it manhandled them and just wadded them up into balls, that was impressive. UNLV Nevada Test Site Oral History Project 15 I’ve talked to some of the miners about reentry, so they would physically get ways for you all to get back in there and then—? Well, usually what we would do is not go back down the preexisting tunnel because it was too radioactive. We’d usually mine a parallel drift, and then we would mine over from that into the other tunnel and look at it in spots, rather than go all the way down, for two reasons: It was too radioactive, and secondly, it was such a jumble of debris from the energy that had pushed all the stuff into a big blob. So you’d be taking a look at these different perpendicular or whatever into it. Yes. How long would that process take? How long would you stay