There are a few on OSM, maybe 5%. Don't have website since it's just a one man effort, basically a cron job that runs nightly on a server. Might spin up a little website with docs/information.
Edit: I'm now on some NSA list, aren't I? Hi guys! Just finished Snowden's book, it was great!
Here's an example mine area: https://www.openstreetmap.org/way/627538334#map=17/44.32936/...
I would suggest adopting hazard=minefield (in addition to the other tags you use) for use on paths/roads/routable objects going over or skirting the minefields as well. The hazard-tag is a proposal, but has been used in the field a good number of times (coincidentally, a few times in Serbia).