4. Mining coal

Climate Change (Stationary Energy and Industrial Processes) Regulations 2009: 9–11

4.1   Overview

The formula for calculating emissions associated with mining coal accounts for greenhouse gas emissions that will occur as a result of the coal being combusted and for fugitive coal seam methane (FCSM) which is released to atmosphere during mining activities.

Recording the volume of mined coal at the point of sale means no stockpile adjustment is needed. All mined coal sold, gifted or used by the participant must be included. Coal which is exported by the miner or sold to an opt-in participant is then explicitly deducted. A deduction is allowed for FCSM which is flared or oxidised.

Information must be recorded for each class of mined coal: lignite, sub-bituminous and bituminous. Because the emissions factor is expressed in energy terms, both tonnes of coal and gross calorific value are required.

4.2   Information you are required to collect

The following information must be collected for each class of coal mined in the year:

Information to collect How to collect
  • tonnes of mined coal sold
  • recorded at the point of sale
  • include coal exported or sold to opt-in participants
  • tonnes exported
  • recorded at the customs point
  • tonnes sold to opt-in participants
  • recorded at the point of sale
  • tonnes combusted by the person for own use
  • recorded at the mine or combustion site
  • tonnes gifted
  • recorded at the mine
  • includes coal provided gratuitously to any person or entity, including an employee
  • calorific value
  • measured on a consistent basis
  • unit of measurement is TJ/t
  • as a gross or higher heating value
  • total tonnes of coal mined in the year
  • by category (surface, underground bituminous coal, or underground mined sub-bituminous)
  • include all saleable coal removed from the mine
  • exclude any overburden or unsaleable coal
  • measured at the mine
  • tonnes of methane flared, combusted or otherwise oxidised
  • measured at the mine

4.3   Example calculation

Valletta Miners Pty Ltd is involved in coal-mining activities in New Zealand. In the year, the company mined 98,786 tonnes of lignite from an open cast mine, 57,897 tonnes of sub-bituminous coal from an underground mine and 69,568 tonnes of bituminous coal from an underground mine.

Ninety per cent of the mined bituminous coal was exported. Twelve thousand tonnes of sub-bituminous coal was sold to opt-in NZ ETS participants, with the bulk of the remaining quantity of coal (bituminous, sub-bituminous and lignite) sold domestically via direct contracts and wholesalers. All mine staff have an annual allowance of coal as part of their employment contracts and this accounted for 210 tonnes of sub-bituminous coal. A further 410 tonnes of sub-bituminous coal is used in an on-site boiler. A total of 750 tonnes of fugitive coal seam methane (FCSM) was captured and flared during the year.

Valletta Miners Pty Ltd has decided not to pursue UEFs for their coal mining activities for any of the three coal classes.

Step one: Record tonnes and calorific value for classes of mined coal sold, used, exported or gifted

Class of coal Sold
(t)
Calorific value
(TJ/t)
Own use
(t)
Gifted
(t)
Exported
(t)
Opt-in
(t)
EF
(tCO2-e/TJ)
Emissions
(tCO2-e)
Mine 1: Lignite 98,786 0.0153 0 0 0 0 94.79 143,268
Mine 2: Sub-bituminous 57,277 0.0213 410 210 0 12,000 90.64 88,610
Mine 3: Bituminous 69,568 0.0289 0 0 62,611 0 88.15 17,723

Step two: Record quantities of total coal mined

Category of coal Quantity
(tonnes)
Emission factor
(tCO2e/tonne)
Emissions
(tCO2-e)
Surface (lignite) 98,786 0.018 1778
Underground: Sub-bituminous 57,897 0.288 16,674
Underground: Bituminous 69,568 0.385 26,784
Methane flared or oxidised 750 17.89 13,417

Step three: Calculate emissions

Emissions for each class of mined coal are calculated as total mined coal sold + coal gifted or used less any exports or coal sold to an opt-in participant.

Data must be entered separately for each component of the equation:
E = [(A × CV) + (C × CV) + (D × CV) – (B × CV) – (BA × CV)] × EF1

Emissions from lignite:
= [(98,786 × 0.0153) + (0) + (0) – (0) – (0)] × 94.79
= 143,268 tonnes CO2-e

Emissions from sub-bituminous coal:
= [(57,277 × 0.0213) + (410 × 0.0213) + (210 × 0.0213)
– (0) – (12,000 × 0.0213)] × 90.64
= 88,610 tonnes CO2-e

Emissions from bituminous coal:
= [(69,568 × 0.0289) + (0) + (0) – (62,611 × 0.0289) – (0)] × 88.15
= 17,723 tonnes CO2-e

Total emissions from the activity of mining coal for the year

An emissions return must record the total emissions from the activity of purchasing coal per annum, calculated by adding together the emissions for each class of mined coal sold, with the sum of FCSM from each category of mined coal, less any methane flared or otherwise oxidised.

= Σ(E) + Σ(ECSG) – (G × EFFLA)
= (143,268 + 88,610 + 17,723) + (1778 + 16,674 + 26,784) – (750 × 17.89)
= 281,420 tonnes CO2-e