Barks had already completed "Land Beneath the Ground" as a 32-page story when Western Publishing notified him that it would have to be trimmed - and quickly. A total of five pages were cut to make room for the text page and the four page Gyro story. The story was published as a 27-pager.
In an article published in 1975, Barks-collector Kim Weston said about the beginning of the story: The first cuts are made between pages 2 and 5 with the net elimination of two pages. And there is almost certainly some redrawing and changes in text. I say this for several reasons. First, some panels look like they have been relettered, or had captions or figures added or changed. Second, the natural rhythm and flow of a Barks story is not present in these pages but disrupted in such a way that I have long had a feeling that something just wasn't right about the story. Now I think I know why -- two pages were cut from the beginning against a tight deadline. Third, I think that if Barks had fully redrawn and rewritten these pages, he would have corrected the subtle imbalances that are there.
A total of almost 2 and a half pages of original material for the story still exist. Two half pages of this deleted art are numbered 5 (bottom) and 7 (top). The bottom half of unpublished page 5 shows the supplies loaded in the cart. Donald asks Scrooge who he plans to have accompany him down as an observer. Scrooge asks Donald if he has $500 and coerses Donald into accompanying him down, using a 1950 I.O.U. for 50 cents that -- at compound interest -- now amounts to $500.
The scene on this half page fits right before the beginning of published page 4 where Donald has a painful expression on his face. The top half of the original page 7 contains a scene of the nephews in the running wild mining cart in which one nephew announces the trick they use in the bottom half of published page 5, which would have been the bottom half of the original page 7. Paste-up shadow in panel 5 of published page 5 shows that Barks added the line of dialogue "But we were smart!" as a transition when he deleted the half page.
The page numbers on these two unpublished half pages leave room for one original page 6, but there is a problem because there is a total of one and a half worth of published material which fits in there: The top and bottom half of published page 4 and the top of published page 5. For me this gives way to the possiblity that the published top half of page 4 wasn't originally following the bottom half of unpublished page 5 (as mentioned in "The Carl Barks Library - Set III"). It might have been made from art cut from somewhere preceding the I.O.U. scene.
The second tier of published page 4 contains a scene in which Donald seems to be loading the mining cart, while in the bottom half of the original page 5 the car is loaded. Donald even emphasizes that by saying "everything" while referring to the expedition outfit. This could give the possibility that the second tier of the top half of published page 4 originally was placed before the bottom half of original page 5. Barks may have put it on its new location by altering the dialogue and adding the frowned expression to Donald.
Retouching like this seems to appear in the first tier of published page 4, where the worried Donald could have been added into the first panel. A close look at the background shading in the panel shows discontinued lines and the panel itself looks like being made of two pieces of art. Possibly these first two panels where also taken from somewhere in between the original pages 2 to the bottom half of original page 5. The worried Donald may also have been clipped from there, though he also might be made especially for the trimmed version. To smooth over the transition from published page 3 to these panels, Barks added (or altered) a text-box, which says "So, in order to find out more about the big hole, Uncle Scrooge asks Donald to go down and look the place over!" The part of the panel containing the nephews studying the rock and the second panel with Scrooge look like they have been left unaltered, though they may be cut on their left and/or right sides to fit in the addition of Donald.
If this theory is true and there are no cuts in published page 1 and 2, this would mean that there is a gap of two and a half pages before the bottom half of original page 5, only to be filled by the material of published page 3 and the art which later could have been turned into the top half of published page 4. That's a total of at least one page worth of lost material. This material could have involved consultation with the professors at the university or a gag about paying the tunnel workers or perhaps Scrooge's preparations for his own investigation after the workers flee.
Putting the material of the top half of published page 4 somewhere before the original page 5 bottom half, according to this theory, leaves exactly one page to fit in between the original page 5 bottom half and the original page 7 top half. This could have been bottom half of published page 4 and top half of published page 5, which would originally have formed original page 6.
There might be more going on, though. This 'original page 6' may also have been made from cut art and/or new art. My reason for saying this is that the caption in panel 5 (panel 1 of published page 5) somehow looks a bit disturbing to me. Also, the car the nephews are filling in this panel has more in common with Scrooge's car than their own in the following panels, which doesn't have the flares in front. (*) Maybe this art is also taken from the gap that follows published page 2? Maybe this panel originally contained Scrooge and Donald filling the car? Besides panel 5, panel 8 also looks a bit strange. Maybe the cable and the pin were inserted later? It looks as if it's drawn separately from the rest of the panel, but this might of course also be coincidence. Still, the dialogue mentioning "some joker" who "has pulled the same cable trick" may have been made to smooth over the cut to the bottom half of published page 5, where a nephew continues by saying "but we were smart" (also added or changed to smooth over the cut). In the story's original form the nephews may have only talked about jokers in the top of original page 7 which fits in between these scenes. Even the words "you invisible jokers" in panel 5 of published page 5 may also have been added or changed. The reason why I say this is that the word "joker" becomes a bit repetitive by having the top half of original page 7 back in the story.
* A contradiction to this may be that flares can be seen in their cars, too, in the top half of original page 7.
If this theory - or at least the thought behind it - is true, the surviving two half pages for original page 5 and 7 were taken out of pages which were heavily mixed and retouched during the trimming of the story.
After the top half of original page 7, followed by the bottom half of published page 5, the story looks unbroken through published pages 6 and 7 (8 and 9 originally) up to panel 1 of published page 8. Panel 2 of this page was made especially for the trimmed version. It shows Donald and Scrooge being fat and soaked, because they "plowed a mile under water before that fool car stopped rolling!" Originally, a sequence of nine panels (originally numbered as page 10 and the first two panels of page 11) took place here. In the lost page, the kids locate Donald and Scrooge behind a pillar, in their mine car, which is looping around inside the arch. The kids suggest that they yank off a sideboard and use it to jam the wheels as a brake (as they had done themselves in the bottom half of published page 5). Donald asks: "How come we don't get any ideas like this?" Scrooge answers: "Don't ask me! I only know how to make money!" The idea works fine, but unfortunately the car stops at the top of the loop. The result of cutting this scene is another page being eliminated from the story length, making a total equivalent of three pages and one panel up to this point (according to the theories!), of which an equivalent of two pages and one panel still exists.
The story picks up with panel 3 of published page 8 (originally 11) and appears to be intact up through published page 20 (originally 23). On published page 21 and 22 there appears to be evidence of more cuts (misaligned panels are the usual evidence). This could mean that the last (almost) two pages may have been cut between the end of published page 20 and the beginning of published page 23. However, only one tier with two panels of these suspected pages is known to exist.
In the first panel, Donald says: "More speed! It's growing pitch dark up here! We can't be farfrom the shaft!" and in the second, two Terry Fermians shout: "Push, you Fermies! Rah! Rah! Rah!" and "Roll, you Terries! Cha! Cha! Cha!" Barks has said this survived tier is "...all that is known to remain from a page or two of cuts." Both the material and Barks' explanation seem to fit with the top half of published page 21. Traces of the trimming process may be visible here, because the Rush- and Roll-balloons look like they were added afterwards. Also, the atypical "Soon!" caption looks as if it was added to panel 3 afterwards. Other cuts in published page 21, 22 and maybe even 23 could have contained one or more chasing sequences, earthquake gags and / or sequences involving the escape from the cave and the moving money-bin. From published page 24 (originally 28?) to published page 27 (originally 31), the story could have been left as it originally was drawn, though there's of course the possibility that art has been cut from the top half page of published page 27.
According to my theories there's room for a cut equivalent of one page and seven panels after published page 8 (originally page 11). With the remaining two panels of survived art this gap becomes an equivalent of one page and five panels. This art may all have extended art from the published version, but there may also be the possibility that there's a gap somewhere else in the story. The reason why I say this is that two things from the Ducks' outfit at the beginning of the story are clearly mentioned, though not used at all: the camera (bottom half of original page 5) and the telephone (published page 5). Maybe it should be clear that the demolished car in the cut two panels of original page 11 (after having fallen down the loop) can't contain an undamaged camera? The disappearance of the phone may also be clear, because it seems to be left behind when the nephews are pushed into the land beneath the ground. Still, I find it strange that these materials disappear so invisibly while they're emphasized earlier in the story. Maybe they were foreshadows of what happened later in the story before the trimming took place? Maybe the underground radio wire system originally also had something to do with the phone wire system? In panel 3 of published page 15, a nephew whispers to Scrooge that they've "only a little while left to get back up the shaft and warn the people to flee!" This means that getting contact with the world above is at least a concern and so the phone might have at least been mentioned somewhere in a cut part.
Two points in the story which may smooth over a cut are panel 3 of published page 10 and panel 6 of published page 13. Both panels contain two nephews talking two each other about Terry Fermy. As published, these conversations appear to be sidenotes, but maybe at least one of them originally lasted longer? I especially find the caption in panel 6 of published page 13 a bit strange because it says "the ducks soon find real cause for worry", while in the previous panels there's no mention of worry at all. In panel 5 of published page 13, the nephews come up with the idea to tell their troop commander about Terry Fermy so that "he can have it printed in the Junior Woodchuck's guidebook". Maybe one of the nephews suggested making a picture for their troop commander as well, possibly because the troop commander may not believe them? This could mean that they discover having neither the camera nor the phone, which may be the cause for worry referred to in panel 6. Whatever happened, a trace from a possible cut may be visible in the right balloon of panel 5, which doesn't have a border on its right side. However, this is just guessing, the cuts containing scenes like the ones I just mentioned - if any - may also have been made elsewhere.
The surviving two and a half pages worth of cut art are published in "Uncle Scrooge - His Life and Times" and "The Carl Barks Library - Set III". Except for the tier that should fit somewhere on published page 21, the art has been inserted in the story again. The tier is published apart from the story. Since a full reconstruction was not possible and the pieces don't fit exactly, some minor changes are made. In the first panel of published page 4 the caption is changed to "Donald is stuck! He has to go down and look the place over!". In the first panel of the bottom half of original page 5, a caption is added ("So, Scrooge outfits an expedition himself!"). Of this panel, the original is shown in the accompanying article where the original texts of the alterted captions are mentioned. In panel 5 of published page 5 (on page 484), the paste-up shadow mentioned in this article is removed, explained by the editors with the footnote: "In the original edition of 1956 and subsequent printing by Western Publishing, a thin line of shadow appears just beneath the first dialogue balloon in panel 5. It has been cleaned up in the current printing." The phrase "But we were smart!" in this panel is changed to "We were smart!"
In a 1974 interview with Michael Barrier, Barks discussed this story: "I cut quite a number of pages out, myself. ...I can't recall whether they sent it back to me or whether they notified me while I was still working on it, and told me that instead of a thirty-two page story they were going to have twenty-seven pages. ...I cut out the stuff that I considered sort of padding. ...It was the stuff that wasn't absolutely nescessary to the continuity of the story. ...They were good enough gags to keep the story moving."