This is a new coal mod that adds a new item for better smelting capacity. This new coal item can smelt/blast up to 64 items per coal!
The coal is called "Lava Infused Coal." Additionally, it does not get consumed in the furnace, making it essentially infinite.
Here is a demonstration:
As you can see, the coal does not get consumed in the blast furnace, and you get around a full stack of smelting.
