Rule 12 Metallurgical processes
The discharge of contaminants into air in connection with:
(1)any production or processing of metals (such as the melting of any metal or metal alloy, including secondary melting and the sweating of scrap metal) where the aggregated melting capacity is less than 100 kg/hour;
is a Permitted Activity, provided it complies with the conditions below, and excluding any discharges of contaminants to air arising from processes involving:
(a)the extraction, including electrochemical methods of reduction, of any metal or metal alloy from its ore, oxide, or other compound;
(b)the making of steel or the refining of any metal or modification of any alloy in a molten state by blowing with gases or by the addition of reactive chemicals of volatile fluxes and the use of oxygen lancing in scaring and similar operations;
(c)the emission of any hazardous air pollutants listed in Appendix 1;
(d)hot-dip galvanising or other processes for the protection of surfaces by metal coating using fluxes;
(e)the desulphurisation of iron, steel or any ferrous alloy;
(f)the heating, in a furnace or other appliance, of any metal or metal alloy for the purpose of removing grease, oil or any other non-metallic contaminant (including such operations as the removal by heat of plastic or rubber covering from cables); or
(g)the melting, including secondary melting and the sweating, of lead, at a rate exceeding 25 kg/hour.
The person(s) responsible for the activity shall ensure that:
(i)there is no discharge of particulates of a concentration greater than 250 mg/m (at STP), measured at the point of discharge;
(ii)there is no smoke, dust, odour, gas or vapour from the process, which is noxious, dangerous, offensive or objectionable at or beyond the boundary of the property; and
(iii)the discharge to air is vented through a chimney(s) or vent(s) which discharge at a point which terminates at least 3 metres above the level of any adjacent area to which there is general access.
Explanation:Rule 12 relates to the discharge of contaminants to air involving the processing of metals. Rule 12 relates to all instances where contaminants are discharged to air from the processing of metals, regardless of whether undertaken as part of an industrial or trade process. The Rule permits the production and processing of metals at a rate where the aggregated melting capacity is less than 100 kg/hour, subject to compliance with the stated conditions. This includes the melting of any metal or metal alloy, including secondary melting and the sweating of scrap metal. Secondary melting involves the melting of processed ore. The sweating of scrap metal is a process involving the heating, usually of metal components, to extract valuable metals.
Rule 12 explicitly excludes a range of metal processing activities from the permitted activity class. Those activities listed in sub-sections (a)-(g) require a resource consent under Rule 23, regardless of where they are undertaken or the aggregated melting capacity.
The conditions in Rule 12 require that there is no discharge of particulates of a concentration greater than 250 mg/m 3 (at STP), measured at the point of discharge, that there are no offensive, objectionable or noxious discharges, and that discharges are vented through a chimney(s) or vent(s).