677Production of clinker

#### 677 Production of clinker (1) The production of clinker is the physical and chemical transformation of: (a) either or both of calcium carbonate compounds (limestone (CaCO3)) and other calcium carbonate (CaCO3) feedstocks; and (b) any of the following: (i) clay; (ii) clay mixed with 1 or more feedstocks that contain 1 or more of the following: (A) silicon dioxide (SiO2); (B) iron (Fe); (C) aluminium oxide (alumina (Al2O3)); (iii) 1 or more feedstocks that, when combined, contain all of the following: (A) silicon dioxide (SiO2); and (B) iron (Fe); and (C) aluminium oxide (alumina (Al2O3)); that are fused together at a temperature above 1000 °C into Portland cement clinker. (1A) The production process may or may not involve the physical transformation of Portland cement clinker into cement through a process of comminution with gypsum or other additives. However, the process must involve the production of clinker as described in subclause (1). (2) The Portland cement clinker must: (a) have a concentration of calcium silicates equal to or greater than 60%; and (b) have a concentration of magnesium oxide (MgO) equal to or less than 4.5%; and (c) be useable in the making of Portland cement. (3) The production of clinker is specified as an emissions‑intensive trade‑exposed activity.