The Long Dark

Coopers solution seems to relate to the original version of the game. The redux update has now changed all of this. "Survival School" is no longer a passable chapter, it's just an ongoing side mission.

After you saved Jeremiah at the start of chapter 2 he sends you on a long trek to the Broken Railroad region to recover the spear. After you find it, fix it and return to him he sends you out again to get 3 transistors from radio towers in Forlorn Muskeg. You're going to get a bear encounter at a couple of these radio towers so arm yourself with the spear when you get close. You need to wait until the bear stands tall and is about to charge, then press and prepare to mash to fight. This usually happens 3 times before the bear leaves you alone.

Once you have all 3 transistors head back to mystery lake but as you reach the train tunnel transition point the bear will attack again. This time it's a cutscene so there's no fighting and you'll end up in a large cave system with the bear stalking you. Follow the linear path to the "room" where you finally spot your spear. Sneak around the perimeter of the cave moving from one safe spot to the next until you can finally grab the spear. Fight the bear off another 3 times and you'll finally kill him. You'll now get a long cutscene and the achievement should unlock.