Make your way down the tunnel that opens until you reach a fork in the path. Before entering either passage, look on the crates to the left of the track for an Archivist’s Map. Take the shorter right hand path first for a bit of Magnesite Ore and then move down the left hand tunnel to continue. Take the zip line at the end to reach the area below.
As you land, loot the locker to the right and continue through the doorway to reach a flooded tunnel. Take the left hand passage first to find a Survival Cache [15/21] at the end.
Head back into the water and swim to the other side this time. Find the passage out of the water here. Loot the crate of Salvage and then pick up a bottle from the container near the locker. Craft a Molotov and use it to destroy the canvas blockage ahead. Move through when it is safe to do so and jump to the handhold on the far side of the pit for a scene.
Enter the tunnel and follow it to the right. At the bottom of the first set of stairs, check out the alcove to the right for a crate of Salvage and another Survival Cache [16/21] . Continue down the next set of stairs (and watch out for a bit of collapsing floor action) to find a room at the end with a crate of Cloth and a chest on a desk holding a Relic [14/18 – Hip Flask] . Inspect the top of the Relic to improve Lara’s Russian.
On the left side of the room you’ll find a canvas barricade behind a burst pipe. Grab a bottle and craft a Molotov Cocktail. Stand opposite the burst pipe and angle your throw over the water so that you’ll hit the cloth behind it on the full. This will remove the obstacle.
Jump through the water onto the wooden platform to get a nice view over the puzzle area below. Hop across to the platform on the left and hug the left hand wall to find a small desk holding a Document [21/26 - Greek] . Behind the mine cart by the exit is an Explorer’s Satchel .
Continue out the exit and down the stairs until you reach a new base Camp ‘Excavation Shaft’. Climb the handholds here to find a small ledge with a cylinder of reagents. You can use the Base Camp here to apply any upgrades you require and spend any skill points you have. Exit the Base Camp menu when you are ready to continue.
Jump across to the platform ahead and climb to the top. Hop across to the far walkway and grab the crate of Cloth in the corner. Head up the stairs, grabbing the piece of Magnesite Ore as you go. As you reach the top, look to the right to see a chest with a Relic [15/18 – Bomb Fuse] on a crate in the corner. In the room opposite the top of the stairs you’ll find a locker to loot and on the table a Document [22/26 - Greek] .
Return to the top of the stairs and jump over to the hanging container full of stones. This will release some carts. Drop down and return to the top of the stairs. This time use the ramp on the right to climb up to the platform above. At the top, look towards the opposite end of the room from the hanging containers of rocks to see a cylindrical mechanism. Attach your Rope Arrow to the location provided to release another cart.
Drop down to the previous platform (at the top of the ramp) and jump to the beam protruding from the wall. From here we can swing and jump to a ledge above where we looted the Document earlier.
Climb to the next level up to find a Mural [10/12 - Russian] . Continue to climb until you reach the walkway at the top. Behind the waterfall you’ll find a pillar with rope strung around it and behind this a small passageway leading to a cylinder of reagents.
Stand next to the pillar and use a Rope Arrow on the mine cart below. Return to the platform at the top of the stairs and leap across to the hanging cart filled with rocks once again. This should move our rope-attached mine cart into a position that will divert the water from the canvas blockage behind it.
Hop to the platform closest to this and use the bottle here to craft a Molotov. Use it to burn down the obstacle. Jump across to the new opening and continue inside.
As you enter, look amongst the bunks to your left for a piece of Magnesite Ore . Climb the stairs nearby to find an altar of sorts containing a Codex we can interact with to complete the Challenge Tomb [03/03] .
Before leaving, loot the pile of Byzantine Coins by the altar and a pair of cylinders with reagents. Exit via the tunnel and grab the box of reagents. By the stone circle inside you’ll find another pile of Byzantine Coins on the right and behind the left hand light, a Survival Cache [17/21].
Scramble up the white wall at the back of the room and use the ladders and climbing walls to reach the top. Pull down the blockage at the end using a Rope Arrow and hop across the gap in front. Now backtrack through the area until you find your way back to the tomb’s entrance at the copper mill.