There are a total of 250 mithril block across whole middle-earth.
there are 3 ways to eran them
*Stoy mission
*Side missions
*Exploring
*Story missions
Each mission contains 5 mitrhil blocks.
*You get 1 for completing the mission,
*You get 1 for finding the design,
*You get 1 for achieving True Adventurer,
*You get 1 for getting the 3 lost items,
*You get 1 for finding all the chests.
There are a total of 18 story mission. So 18*5= 90 Mithril block from the story.
*Side mission
there are a total of 50 side quests 20 of those gie you a Red Brick the other 30 give you a Mithril block.
*Hobbiton: Here are 4 missions 3 of those give you a Mithril block.
*Bree: Here are 5 missions 2 of those give you a Mithril block.
*Weathertop: Here are 2 missions 1 of them gives you a Mithril block.
*Rivendell: Here are 3 missions 2 of those give you a Mithril block.
*the Pass of Caradhas: Here are 4 missions 3 of those give you a Mitrhil block.
*Lothlórien: Here are 3 missions 1 of them gives you a Mithril block.
*Amon Hen: Here are 3 missions 2 of those give you a Mithril block.
*Emyn Muil: Here are no missions.
*the Dead Marshes: Here are 3 missions 2 of those give you a Mithril block.
*The Black Gate: Here are 2 missions 1 of them gives you a Mithril block.
*Isengard: Here are 2 missions 1 of them gives you a Mithril block.
*Helm's Deep: Here are 3 missions 2 of those give you a Mithril block.
*Edoras: Here are 5 missions 3 of those give you a Mithril block.
*Minas Tirith: Here are 2 mission both give you a Mithril block.
*Minas Morgul: Here are 4 missions 3 of those give you a Mithril block.
*Cirith Ungol: Here are 5 missions 2 of those give you a Mithril block.
This concludes a total of 30 Mithril blocks from side missions.
*exploring
Before you go Exploring, make sure you have atleast the Beserker and a strong person who can lift the oranges handles.
The Beserker can be found at Helm's Deep. Or you can use this code in the menu: UE5Z7H
*Hobbiton: Here are 9 Mithril blocks.
*Bree: Here are 8 Mithril blocks.
*Weathertop: Here are 12 Mithril blocks.
*Rivendell: Here are 8 Mithril blocks.
*the Pass of Caradhas: Here are 8 Mithril blocks.
*Lothlórien: Here are 8 Mithril blocks.
*Amon Hen: Here are 8 Mithril blocks.
*Emyn Muil: Here are 2 Mithril blocks.
*the Dead Marshes: Here are 8 Mithril blocks.
*The Black Gate: Here are 14 Mithril blocks.
*Isengard: Here are 7 Mithril blocks.
*Helm's Deep: Here are 6 Mithril blocks.
*Edoras: Here are 8 Mithril blocks.
*Minas Tirith: Here are 8 Mithril blocks.
*Minas Morgul: Here are 8 Mithril blocks.
*Cirith Ungol: Here are 8 Mithril blocks.
This concludes a total of 130 Mithril blocks
90+30+130= 250 Mithril blocks in total.
Doing this will net you the achievements: "There's some good in this world" "Ready for another adventure" "Here's a pretty thing!" And al the story related achievements.