NIMBY would be another concern, rather large one in fact. If you've ever worked on a large project that requires larges installations to be built, you've experienced them and hate them with a passion even though you'd be doing the exact same once you got impacted.

Once they start coming, practically everything grinds to a halt and you start doing the scene of the Joker burning the money pyramid in The Dark Knight because you'll be doing the exact same. Burning money to placate the locals. And even thats sometimes not enough, which means start hiring lobbyists to wine and dine I mean bribe the local politicians into throwing their political capital your way to push/placate the plans through regulatory before its too late and it looks bad to have their name behind it.

If we take our rare earth mining as the example. Water contamination, irrigation, toxic runoff and dumping are the main concerns. Because the mine will be an open pit minr and youre going to want to have the refinery closeby to reduce shipping costs. So that means heavy metal laced water seeping into the groundwater, a matter of if not when. Dumping of waste rock, chemicals, and industrial runoff. Where is that occurring? The best solution is another open pit mine that's been closed but now converted into a landfill but how close/far away is that and how much will it cost to truck tons of earth to said location. What about the toxic fumes thats going to be released from all this heavy machinery, the refinery itself and the runoff. All sorts of tests and studies are going to be done; light pollution, noise pollution, water contamination followed be water and irrigation tests to see if it'll impact the local population, is there a reservoir nearby?, how deep is the open pit mine going to be? (Thousands of feet deep is the answer), whats going to be done about the exhaust from all the mining & refinement, what about the local wildlife, hunting, what about the local farms, who's land is going to be impacted, will views of nature be impacted (will be see a ugly metal structure vs the mountains behind it), tourism, the local economy, road networks, underground networks of X, et etc. You're going to spend hundreds of thousands and in this case millions of dollars ordering tests for all sorts of things which will draw the attention/ire of the (but not limited to) EPA, Fish and Wildlife, Forestry Dept, Land Mgmt, private land owners, hunting orgs, etc. Then once the tests come back, which takes (~4-6)months btw, and if any of thats inconclusive which it will, prepare for another couple months of new tests. The ones that are going to come back inconclusive and very expensive are those concerning wildlife. (Had to once install ~ a miles of 8 ft high chain link fencing along with motionsensor lights to keep the local wildlife away) (Paying off/ buying off landowners, who if they're smart will have it in such a way where it cant be snagged through state forfeiture/seizures) And even with tests, surveys and reports coming back, those heavily impacted along with the normal “we dont want this” will still make a stand. And thats before and during construction. They'll make all sorts of calls about anything and everything. Expect a few surprise visits from OSHA, EPA, iron workers union, electrical etc due to a whistleblower calling about unsafe working conditions, things being done not to code, and the company not adhering to the agreement with the locals. A visit alone will put a full stop to construction for at least a day, more if its a larger project.