It may be produced from rock, gravel, metallurgical slag or artificial stone.

With metallurgical slags there is also the possibility that you are adding flux or mineralisers to the kilns.

Other Metallurgical Slags -- The application of slag produced in the smelting of copper, zinc, lead, nickel and tin has yet to be explored fully.

Trench Talk: As we previously informed you of, a great deal of metallurgical slag has been recovered from a feature at the north-eastern end of Trench O. This was certainly the case today.

A material composed of discrete mineral particles of specified size or size distribution, produced from sand, gravel, rock or metallurgical slag, using one or more of the following processes selective extraction, screening, blasting, crushing.