This is a very informative and high-quality video that explains what goes into the safe and efficient disposal of explosives, the shelf life of which has ended.
The Finnish Defense Forces maintain must maintain large stockpiles of munitions for readiness reasons to last for a long time of high intensity combat. Training use makes up a small fraction of the amount of explosives that need to be disposed of annually.
The mass detonation camp is located in the far north of the country.
The video has English subtitles that you need to set on.