Captruing Mine Tunnels 3d Mesh

Good day team.
I have developed a functional Three.js application whereby I am showing mining data as 3D objects. For example i have a drone capturing images which I am then processing into 3D Meshes.
Its working very well. My question is that now I want to capture 3DMesh of underground tunnels , where there is not network and the path is not all visible from one point , hence my drone cant fly down there. What can i use to scan the tunnels which go as far as 1km long and 300m depth from surface. I want to be able to capture both the actual shape and the imagery of the tunnels. What can i use?

I’m afraid but you need to ask this question somewhere else as it’s not related to this library or even software. You need to search for 3D scan hardware and/or ask in a related community for that.