Canyon

Ignoring the no trespassing sign, I found a military camp.
I called out, "Is there anyone?", But only Freddie was there.
He even has a guy in a cage.
I managed to get rid of the barricade written "Do not enter" and cross the bridge.
The gorge ended, and I could see OL' DUTCHMAN MINE (former Dutchman mine) below.
There is also a gift shop next door where you can resupply.
Instead, I could see them crawling on the cliff on my left.
A closer look reveals that the mine door is closed.
The open/close lever doesn't seem to have electricity and doesn't respond.
It may also be a power generation facility in the direction where the electric wire is extending.
First, I decided to look into the gift shop for supplies and clues.
== item location ==
Inside the tent at the campsite
[M67 Fragmentation Grenade x 2]
* Repop until the barricade is destroyed
Refrigerator in tent at campsite
[hamburger x 2]
Locker inside a tent at a campsite
[mask]
behind the tent at the campsite
[Handgun Ammo x2, Mask]
behind the tent at the campsite
[mask]
In front of the camp cage
[Handgun Ammo x2]
Right rear seat of Humvee at campsite
[Handgun Ammo x2, Walther P38]
Humvee right front seat at the campsite
[mask]
After crossing the barricaded bridge
[Handgun ammo x 3]
Gift shop 1st floor central shelf
[Handgun Ammo x2]
The shelf at the back of the gift shop on the 1st floor
[Machine Gun Ammo x2, Mask, Ingram M10]
Large cabinet on the far right on the 1st floor of the gift shop
Left row 2nd stage M67 Fragmentation Grenade × 1
Left row 3rd row [handgun ammo x1, M67 Fragmentation Grenade x1]
Middle row 1st row [handgun ammo x 1, machine gun ammo x 1]
Middle Row 2nd Row [Handgun Ammo x 1]
Right row 2nd row [handgun bullet x 1, hamburger x 1]
Refrigerator on the 2nd floor of the gift shop
[hamburger x 2]