The Coal Dimension is a dimension added by MoreDimensions.
Entering and Exiting the Coal Dimension
Entering the Coal Dimension is similar to entering The Nether. However, instead of using Obsidian, Blocks of Coal are used. Additionally, the portal is activated with a Coal Igniter rather then Flint and Steel.
Similar to The Nether, when entering the Coal Dimension another portal is auto-generated within the new dimension.
The Coal Portal makes noise, like the Nether Portal.
The Coal Dimension's world generation is similar to The Overworld, but it generates Blocks of Coal and Coal Ores rather than Grass and Dirt and Stone.
Like The Overworld, the Coal Dimension has a sequence of day and night, but without rain.
There are no mobs implemented in the Coal Dimension yet.