A good point about people being able to throw heavy things, but trying to flip a log mid-air and dropping a suitably heavy object onto a precise point are two different things.
Assuming all mines in game are anti personnel and not anti tank, you would need between 15-20 lbs of pressure to trip the detonator depending on the type. (German S-mines, or bouncing Betties, needed about 7kg where US M14 blast mine needs about 9kg)
Source: https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.scienceabc.com/innovation/how-do-landmines-work-explosion-dangerous-anti-personnel-anti-tank-explosive-destruction.html&ved=2ahUKEwj90o2nopfjAhUyAZ0JHZFKCR8QFjALegQIARAB&usg=AOvVaw1FnHFn9ra4fJqACqTuy_S-&cshid=1562106321889
Given the blast radius, I believe it would be difficult to safely throw a 20lb object from far enough away to a precise point to safely detonate a mine by throwing something at it. Beyond the blast radius, there is the shrapnel cone. I would imagine even if you do manage to set off a mine and stay out of the explosion itself, you wouldn’t be able to get beyond the range of shrapnel. -Maybe- if you hunkered behind a tree, you might be spared any injury, but you didn’t mention using trees as cover, you mentioned chunking them into the air.
And sure, our ability to throw objects did allow our early ancestors to expand their food base, but they weren’t throwing logs or 15-20lb rocks at 8oz birds or 2lb squirrels. Any larger animals weren’t hunted with a handful of rocks, but maybe kept at bay or shooed away by them and any larger stones would have probably only been picked up to finish off larger game already incapacitated by a spear or club.
