How can I value a commercially accessible CAVE property?
As the title says, how would one value a cave property that is commercially accessible?

The property is what remains of an old mine. It is completely stable and intact. It lies on a relatively trafficked road, has three acres outside the cave, and roughly six acres inside the cave. Average ceiling height is 20 feet. A full size tractor trailer can be driven into it, and turned around without backing up. In addition, there are subterranean flooded portions of the cave with high grade water estimated to be more than 200 million gallons.

I can't seem to find anything online about how one would appraise such a property, but if anyone can point me in the right direction, it would be much appreciated.
[{"id": "ea2towf", "text": "Cave that big will probably run you about three Mastodons. ", "replies": [], "depth": 1}, {"id": "ea2vatc", "text": "Man, that sucks. \n\nAny environmental issues? Highest and best use? Land value? \n\nAre their utilities in the cave? You can value the mineral rights as those would also go with the property. \n\nGood luck there buddy. I have seen mega churches, seaweed farms, but this one may be the worst one yet. ", "replies": [{"id": "ea2vo7o", "text": "No environmental issues. As in the info, it was an old mine but was then transformed to grow mushrooms as it is a constant temperature year round. The land value outside the cave itself would be high as it is all along a heavily trafficked road near the middle of a medium sized city. \n\nThere are no utilities inside the cave but they can be easily installed. And again, it is naturally climate controlled. \n\nWhat makes you say this is the \"worst\" and not the \"best\"? ;)", "replies": [{"id": "ea306b4", "text": "There are old salt mines that have been used for record storage facilities. I\u2019m sure there have been other depleted mines sold somewhere in the US. You\u2019ll need a very specialized appraiser. I\u2019m with the poster above. I\u2019ve seen some weird stuff appraised from industrial hazardous waste landfills to lobster farms but yours is up there on the I don\u2019t have a fucking clue meter. ", "replies": [], "depth": 3}, {"id": "ea30aot", "text": "Mine subsidence is a concern and could affect the value of the property negatively compared to a similar property without a mine.  \n\nA mine is cool and unique to have on a property but unless it's tied to something, like a business, that is shown to generate income (like a building on a property) then I don't think an appraiser can assign much value.  \n\nDisclaimer:. I have no cre experience", "replies": [], "depth": 3}], "depth": 2}], "depth": 1}, {"id": "ea2vo3v", "text": "What does \u201ccommercially accessible\u201d mean? And what are any future benefits that can be capitalized from this cave?", "replies": [{"id": "ea2vrib", "text": "The outside portion of the property (roughly three acres) is along a road. I guess what I was trying to convey is that you can drive into the cave, from the road, as it stands right now. ", "replies": [], "depth": 2}], "depth": 1}, {"id": "ea2vqvr", "text": "As someone who only has about 8 years in CRE......good fucking luck. \n\nThere will be a tax basis.\n\nI'd use your local GIS to look up other cave owners and reach out to them and see if they're willing to point you in the right direction.\n\n", "replies": [], "depth": 1}, {"id": "ea2xhfi", "text": "I might consider looking into replatting the property, selling the more commercially viable dirt first,", "replies": [], "depth": 1}, {"id": "ea2ym3l", "text": "Put it on eBay....", "replies": [], "depth": 1}, {"id": "ea3jbmx", "text": "Disclaimer, I have zero experience with \u201ccave properties\u201d...that said, as others have alluded to you should split the aspects of the property so each part can be valued separately. Maybe there is a use for the cave that is associated with a more typical CRE purpose, but even that would be highly specialized aka very few trades and difficult to value. Figure out the value of the land that is developable irrespective of the cave, tackle the cave as a stand alone, then maybe spend some time evaluating a specialized use that integrates the two. But again with that last approach, even if you find an income valuation that is logical, I can\u2019t imagine you\u2019ll find many if any trades to back up yield rates.", "replies": [{"id": "eaj8jzd", "text": "Thanks for your response. ", "replies": [], "depth": 2}], "depth": 1}, {"id": "ea42pnz", "text": "Check out mining communities to see what old mines have sold at. I'd avoid coal though, as there is typically a lot of environmental issues.", "replies": [], "depth": 1}, {"id": "ea43cb5", "text": "You just need a specialized appraiser for it.  I know some that have done tourism caves, but not any storage/water caves like this.  Just a heads up, you're looking at a really high cost do appraise this thing.  I'd say 50k plus.", "replies": [], "depth": 1}, {"id": "eaa52r0", "text": "What's your position relative to the property - acquisition principal, appraiser,  lender,...?\n\nI'm an investor in a fund that's acquiring a significantly larger cave.  PM me a bit more detail and I might be able to make an introduction if it makes sense. ", "replies": [], "depth": 1}, {"id": "eakx8ph", "text": "This may be relevant to you. [https://louisvillemegacavern.com/attractions/mega-underground-bike-park](https://louisvillemegacavern.com/attractions/mega-underground-bike-park)", "replies": [], "depth": 1}]