Magma.
The molten rock ejected by a volcano from its crater or fissured sides.
A shade of red, named after the volcanic lava.
Tailings: waste rock from which the wanted gold, minerals, opal, etc., has been extracted.
Rubbish, waste matter.
Nonsense, rubbish.
A mess; the result of a blunder.
Overburden: waste material generated while searching for minerals or while mining, such as when sinking a shaft.
To clear waste material out of a mine.