12.3 Mining, Climate, Reforestation, Coal & Energy-Transition Minerals

Mining contributes to climate change through fuel combustion, purchased electricity, explosives, land-use change, processing reagents, and value-chain transport. It also supplies materials needed for grids, electric motors, batteries, wind turbines, solar systems, and other lower-carbon infrastructure. Engineering judgment must hold both facts at once: demand for transition minerals does not erase site impacts, and mine impacts do not erase society's material requirements.

Greenhouse-Gas Accounting

A practical inventory groups emissions:

• Scope 1: direct sources controlled by the operation—diesel fleets, generators, process fuel, fugitive methane, and some blasting or process reactions.
• Scope 2: indirect emissions from purchased electricity, steam, heating, or cooling.
• Scope 3: other value-chain sources—purchased goods, capital equipment, contractor activity, product transport, processing, and end use where applicable.

For activity $i$:

$Emissions_i = Activity_i \times Emission\ Factor_i$

If haul trucks consume 8 million litres of diesel and the selected documented factor is 2.68 kg CO2 per litre for combustion, the direct carbon-dioxide estimate is $8{,}000{,}000 \times 2.68 = 21{,}440{,}000$ kg, or 21,440 t CO2. A complete inventory separately evaluates methane and nitrous oxide and states factor source, boundary, and whether upstream fuel emissions are included.

Reduction Hierarchy

1. Avoid: reduce unnecessary stripping, haul distance, rehandling, and idle operation.
2. Improve efficiency: optimize dispatch, ventilation-on-demand, pumping, comminution, and maintenance.
3. Substitute energy: electrify feasible equipment and procure or generate lower-carbon electricity.
4. Change process: improve recovery, ore sorting, preconcentration, or water management where life-cycle results improve.
5. Address residuals: use credible removals or offsets only after direct reductions, with transparent quality criteria.

A renewable installation must be matched to duty. Solar output is variable; ventilation and dewatering are continuous critical loads. Grid interconnection, storage, dispatchable backup, load shedding, and black-start strategy determine whether a renewable fraction is reliable.

Coal and Climate

Coal combustion oxidizes carbon to carbon dioxide:

$C + O_2 \rightarrow CO_2$

It can also emit sulfur oxides, nitrogen oxides, particulate matter, mercury, and ash constituents depending on fuel and controls. Underground and surface coal operations may release coal mine methane from seams and goaf. Methane capture and beneficial use can reduce venting, but monitoring is essential because leaks can undermine the benefit. Controls for local air pollutants do not necessarily remove carbon dioxide; flue-gas desulfurization, for example, addresses sulfur emissions rather than decarbonizing combustion.

Reforestation and Rehabilitation

Trees remove atmospheric carbon while growing and may improve erosion control, habitat, shade, and water regulation. Credible claims require:

• additionality: the planting would not otherwise occur;
• permanence: stored carbon is protected against fire, clearing, and failure;
• leakage: protection does not shift deforestation elsewhere;
• measurement: baseline, species, survival, growth, biomass equation, soil effects, and uncertainty are documented; and
• ecological fit: native or appropriate mixed species support landform and post-mining objectives.

A hectare count is not a carbon result. Survival, biomass, time, and counterfactual baseline matter. Reforestation also cannot substitute automatically for preventing loss of old-growth habitat, whose ecological functions and carbon stocks take long periods to replace.

Critical, Transition and Rare Metals

Terminology depends on policy and supply risk. Critical minerals are important to an economy or technology and vulnerable to disruption. Transition minerals support low-carbon energy and electrification. Rare-earth elements are the lanthanides plus yttrium and often scandium; “rare” does not mean absent in crust, but economically concentrated and separable deposits are limited.

Resource efficiency includes longer product life, repair, reuse, recycling, design for recovery, and recovery of co-products. Recycling reduces primary demand but cannot instantly supply a growing stock because much material remains in long-lived infrastructure. The exam-ready conclusion is a balanced systems answer: quantify the mine footprint, reduce it at source, design reliable lower-carbon operations, and evaluate the full material chain.

Compare on a Life-Cycle Basis

An electrification or energy-transition option should include source generation, transmission, charging or fuel infrastructure, embodied materials, utilization, replacement, maintenance, operational emissions, recycling and end-of-life. Avoid shifting emissions or impacts outside the mine boundary without disclosing them. For land-based removals, monitor survival, growth, fire, drought, leakage and reversal over the claimed permanence period; hectares planted are not tonnes durably removed.