How to activate the Mountainator Cannon in Genshin Impact

gamepur.com:

Players exploring the Chasm region in Genshin Impact will eventually come across a dead end. There is a pathway in the Underground Mines area of the Chasm that is completely blocked by a massive boulder. Players attempting the Chasm Delvers questline will need to demolish the blockage using a nearby cannon.

Before you can fire the cannon, you need two keys to access the gunpowder storehouse. Once you interact with NPC Jinwu during the Chasm Delvers questline, the locations for both the keys will automatically get updated on the map. However, these keys are hidden, and you have to take a few extra steps to obtain them.

To get the first key, head to the location near the small pond in Underground Mines. There are a bunch of mobs in the area, so make sure to defeat them before you try to get the key. Once defeated, look for a wooden frame leaning against the wall. There should be an explosive barrel just below the frame, which you need to attack once. This will immediately blow up the wooden frame revealing the key.

The second key is on top of the water distillery. There is a round structure on top of the water distillery barrel, which you need to break. Once done, you’ll get the option to investigate the structure that will ultimately land you the key.

After getting both the keys, head to the gunpowder storehouse and acquire the cannonball. You can now load up the cannon and activate it. However, before you can fire the cannon, you need to change the frequencies of three lamps according to the Safe Blasting Device Signaling Guide. Once done, you can fire the cannon to remove the boulder blocking the path.