Yeah, but it has to fit down a well. In other words, ideally it would be a maximum of 6 inches in diameter (and significantly less if it's going to be widely useful for solution-mined salt caverns).
The "drilled shaft" is the only entrance, and while those are typically huge by well standards (solution mining needs to circulate water, so you have to have room for nested casings/pipes), they're still dramatically smaller than what's described here. You typically have a "hanging string", which is a suspended pipe within the pipe for injecting water with flow around the outside of it back up the well (either to extract gas or for solution mining). You want something that fits down the inside of that so you don't need to pull the hanging string for a sonar survey. It's a big pipe, but you're not going to fit a literal mini-blimp that's a couple feet long down it.
With that said, I do wonder if these have other mining applications. It's not good for solution mining, but it sounds like it could be useful for remote inspection of dangerous levels of conventional underground mines. Conventional mine shafts and levels have to be big enough for people and equipment to fit in, and this seems reasonably sized for that application.
The "drilled shaft" is the only entrance, and while those are typically huge by well standards (solution mining needs to circulate water, so you have to have room for nested casings/pipes), they're still dramatically smaller than what's described here. You typically have a "hanging string", which is a suspended pipe within the pipe for injecting water with flow around the outside of it back up the well (either to extract gas or for solution mining). You want something that fits down the inside of that so you don't need to pull the hanging string for a sonar survey. It's a big pipe, but you're not going to fit a literal mini-blimp that's a couple feet long down it.
With that said, I do wonder if these have other mining applications. It's not good for solution mining, but it sounds like it could be useful for remote inspection of dangerous levels of conventional underground mines. Conventional mine shafts and levels have to be big enough for people and equipment to fit in, and this seems reasonably sized for that application.