How EmiMine calculates
Two kinds of number live in EmiMine: the national account (GhaMEM) and the factors that organisations use for their own mines. Both are documented line by line.
The national account
The Ghana Mining Emissions Model (GhaMEM) estimates the whole mining sector: large-scale diesel, grid and independent-producer electricity, other Scope 1, artisanal energy, and land cleared by artisanal and large-scale mining. It runs 20,000 Monte Carlo draws, so every value is a median with a 95% range. In 2022 the footprint was 4.7 Mt CO₂e (3.8–6.0), and 20% of it was labelled as mining in the national inventory. The results are in a manuscript under review; they are labelled as such everywhere in EmiMine.
Science profiles
Two versions of the land-clearance estimate exist. GhaMEM v1.1 counts living biomass and is the basis of every footprint total and share. The land method v0.2 (draft) adds dead wood and litter, the pools Ghana's inventory estimates, and is used for the inventory-format land rows. The cleared areas agree; the carbon per hectare differs. EmiMine never adds the two together.
Factors for mines
| Source | kg CO₂e per unit | Unit | Basis |
|---|---|---|---|
| Diesel, generators and fixed plant | 2.685 | litre | Stationary combustion, manufacturing industries and construction |
| Diesel, haul trucks and mobile equipment | 2.954 | litre | Off-road vehicles and machinery, industry |
| Petrol (motor gasoline) | 2.280 | litre | Stationary defaults for oil products |
| Heavy fuel oil | 3.074 | litre | Residual fuel oil |
| LPG | 2.987 | kg | Liquefied petroleum gases |
| Natural gas | 56.154 | GJ | Per GJ of net energy |
IPCC 2006 Guidelines Vol. 2: NCV Table 1.2; CO2 Table 1.4; stationary CH4/N2O Table 2.3; off-road CH4/N2O Table 3.3.1. Global warming potentials: IPCC AR5 GWP100. Explosives: CO2 from the fuel oil in the explosive: fuel mass fraction x IPCC diesel CO2 (NCV 43.0 TJ/Gg x 74,100 kg/TJ). The 6% default is the usual ANFO mix; set the supplier value.
Electricity uses Ghana's grid factor for each year from GhaMEM (location-based), and the supplier's own factor for independent power producers (market-based). Renewable supply is zero in the market-based figure.
Land cleared by a mine
Emitted in the year of clearance (IPCC Tier 1: no biomass after conversion). Soil carbon not estimated, as in NID1. Reported separately from Scope 1 as land-use change. Stocks per hectare (median, with the low–high range used for the result's range):
| Class | Above-ground t C/ha | Dead wood + litter t C/ha |
|---|---|---|
| Closed forest (canopy >60%) | 106 (40–139) | 44.6 |
| Open forest (canopy 15-60%) | 31 (17–40) | 15.1 |
| Non-forest tree cover (<15%) and farmland | 23.5 (14–33) | 13.17 |
Root-to-shoot ratio 0.37. NID1 (EPA Ghana 2024) Table 70 stocks as used by the EmiMine land method v0.2.
Uncertainty
National values are medians with 95% Monte Carlo ranges. Medians are not additive: when EmiMine adds medians, it says so. A mine's land-use result carries a low–high range from the stock ranges; fuel and electricity results use central factors and show the factor used.
Rules
- DERIVED and SCENARIO values are never presented as measured.
- No artisanal or informal mining site is located, mapped or described. National totals only.
- Organisation data are private; nothing is published without consent.
- "Unlabelled" is not "missing": most of the footprint is probably in the national totals under other labels.