alt Hacker NewsFor such wealth, basic opsec would be worth it 10000x over, cia folks should know it well. No phone, use old car, pack it with camping gear placed above the gold. Initially go prepare the place, heck even setup a movement-triggered camera there for few weeks. Go where there is lush greenery so you can actually dig 1-2m deep hole in the dirt without dynamite. Learn how to cover place so it looks natural. And learn how to come back to it and find it reliably, day, night, rain, snow doesnt matter. My son could come up with this.
One thing that the Bosnian/Serbian conflict/genocide [0] taught authorities is how to find hidden grave sites. Ground penetrating radar comes in a convenient device that is sized & shaped like a typical American lawnmower.
Soil comes in layers and it would be best to spread ground cloths to capture different soils from different layers and to replace them at the appropriate levels in the ground. While this won't defeat ground penetrating radar, it will make the burial site more closely resemble surrounding soil to make the "signal" harder for the less skilled operators to detect.
Links:
0 - https://en.wikipedia.org/wiki/Bosnian_War