You are playing with other mods like Buildcraft and don't want to have your Overworld ruined by all these Quarry holes? Or you only want a new World to test stuff in?
This Mod adds a complete new Dimension, especially for Mining, but you can do whatever you want to do in it. Just craft some Stone Bricks together with a Pickaxe and you get a special kind of Bricks. They are a little harder to break than normal Stone Bricks and they open you up the ability to visit a new world, the Mining World.
Just build a five blocks high and four blocks wide wall with a three by two hole in the middle (same shape as a Nether Portal). Then you need a new Tool to actually create the Portal. Craft a few Stone Bricks, a Flint and Steel and a Stick together to get the Portal Igniter (Portal Multitool). Then right-click the Portal Frames with it and watch, what happens.
All mods in the list blow are available in the Minecraft Modinstaller (click here)... Alternatively we offer you mods here as a ZIP File you can install manually:
Minecraft
Rating
Requires
Download
1.8.9 Forge
none
1.8 Forge
none
1.7.10 Forge
none
2.8
Installation Instructions (without Modinstaller)
Forge Mods
Open the new launcher and make sure the version of Minecraft the mod requires is already installed.