Mine sites often trip NPI thresholds because of the volume of material they move and the fuel and explosives they use. DCCEEW’s industry FAQs and the NPI Guide set out how the rules apply.
Key points
- Category 1 substances in ore, waste rock and overburden count towards use
- Explosives such as ANFO count as fuel
- Overburden and waste rock movements are not transfers
- Tailings to a tailings storage facility are a mandatory transfer
- Mining and explosives EET manuals apply
Ore, waste rock and overburden
Handling and processing count as use under the NPI NEPM. DCCEEW advises that Category 1 substances contained in mined ore, waste rock and overburden count towards the 10 tonne use threshold, so metals present in the ore body can trip reporting even though the site does not buy them.
Explosives
Explosives are treated as fuel. The full mass of an explosive such as ammonium nitrate fuel oil (ANFO) is added to the fuel and waste burnt when testing the Category 2a threshold of 400 tonnes a year and the Category 2b threshold of 2,000 tonnes a year.
Overburden, waste rock and tailings
- Movements of overburden and waste rock are excluded from the NEPM’s definition of a transfer.
- A tailings storage facility is a mandatory transfer destination and is treated as part of the facility whose waste it receives.
- Spills or leaks from a tailings dam that release a substance to air, land or water are emissions and must be reported if a threshold is tripped.
Where the methods are
The EET manual for mining and the manual for explosives detonation set out the estimation techniques for these activities.
Other mining questions
DCCEEW’s calculating emissions FAQ also covers dust suppression water, buffer zones, gas compressor stations and abnormal events.
The NPI Guide includes a quarry example in which substances contained in rock moved around the site count as use.
Why it matters
Metals in ore can trip Category 1 thresholds at the first stage of mining, well before any processing. Mine operators should test each Category 1 substance present in the ore body, waste rock and overburden against the 10 tonne threshold every year, alongside fuel and explosives use for Categories 2a and 2b.
References & sources
Primary regulatory documents and authoritative references underpinning this answer.
- DCCEEW: Calculating emissions frequently asked questionsdcceew.gov.au
- DCCEEW: Transfers of NPI substances in waste, frequently asked questionsdcceew.gov.au
- DCCEEW: Emission estimation technique manualsdcceew.gov.au
- DCCEEW: National Pollutant Inventory Guide (Version 6.1)dcceew.gov.au
- National Environment Protection (National Pollutant Inventory) Measure 1998legislation.gov.au