Landfill Disposals Tax (Wales) Act 2017 section Schedule 1, paragraph 8

The material in Group 4 comprises only—

Schedule 1, paragraph 8 defines the specific types of material that fall within Group 4 for the purposes of landfill disposals tax qualifying materials.

• Group 4 is a narrowly defined category covering certain thermally processed mineral wastes and incineration by-products.
• Vitrified wastes and residues from the thermal processing of minerals qualify only if they are both fused and insoluble.
• Slag produced from waste incineration also falls within Group 4.
• No other materials beyond these two types are included in Group 4.