1.- This Chapter does not cover :
(a) Slag or similar industrial waste prepared as macadam (heading 25.17);
(b) Natural magnesium carbonate (magnesite), whether or not calcined (heading 25.19);
(c) Sludges from the storage tanks of petroleum oils consisting mainly of such oils (heading 27.10);
(d) Basic slag of Chapter 31;
(e) Slag wool, rock wool or similar mineral wools (heading 68.06);
(f) Waste or scrap of precious metal or of metal clad with precious metal; other waste or scrap containing precious metal or precious metal compounds, of a kind used principally for the recovery of precious metal (heading 71.12); or
(g) Copper, nickel or cobalt mattes produced by any process of smelting (Section XV).
2.- For the purposes of headings 26.01 to 26.17, the term “ores” means minerals of mineralogical species actually used in the metallurgical industry for the extraction of mercury, of the metals of heading 28.44 or of the metals of Section XIV or XV, even if they are intended for non-metallurgical purposes. Headings 26.01 to 26.17 do not, however, include minerals which have been submitted to processes not normal to the metallurgical industry.
3.- Heading 26.20 applies only to :
(a) Slag, ash and residues of a kind used in industry either for the extraction of metals or as a basis for the manufacture of chemical compounds of metals, excluding ash and residues from the incineration of municipal waste (heading 26.21); and
(b) Slag, ash and residues containing arsenic, whether or not containing metals, of a kind used either for the extraction of arsenic or metals or for the manufacture of their chemical compounds.
1.- For the purposes of subheading 2620.21, “leaded gasoline sludges and leaded anti-knock compound sludges” mean sludges obtained from storage tanks of leaded gasoline and leaded anti-knock compounds (for example, tetraethyllead), and consisting essentially of lead, lead compounds and iron oxide.
2.- Slag, ash and residues containing arsenic, mercury, thallium or their mixtures, of a kind used for the extraction of arsenic or those metals or for the manufacture of their chemical compounds, are to be classified in subheading 2620.60.