Glacier mineshaft will be found on mountains.
They will be filled with packed ice and ice stonebrick.
They will be filled with more loot. But glacier mineshaft is a lot more darker cause it uses soul soil torch than regular torch and mobs spawn more
In the glacier mineshaft.
And their is a reason why you wanna go to the mineshaft.
It would be cool if a new ore is inside the mineshaft! so it will make the players want to go to the mineshaft than rather going to a normal mineshaft.
The mineshaft will have less coal or iron
But seing lapiz and diamonds will increase
And the mineshaft will be filled with a new mob called the the frozen skeleton,
Its basically the wither skeleton exept it gives you slowness and weakness.
And the best part about the mineshaft is that the more you explore in it the more darker and atmospheric it gets.