🎓 Lesson 1
D1
Getting Started with Supply Chain Carbon Footprinting
Carbon footprinting a supply chain means adding up all the greenhouse gas emissions caused by every step—from mining raw materials to delivering the final product—to understand its total climate impact.
🎯 Learning Objectives
- ✓ Calculate Scope 1, 2, and 3 emissions for a mine-to-mill supply chain using activity data and IPCC emission factors
- ✓ Explain the difference between operational control and financial control boundaries in Scope 3 reporting
- ✓ Analyze and prioritize high-emission tiers (e.g., diesel haulage, electricity, explosives transport) using tiered estimation methods
- ✓ Apply the GHG Protocol’s 15 Scope 3 categories to classify upstream and downstream mining logistics activities
- ✓ Design a minimal viable data collection plan for Tier 1–2 carbon footprinting in a mid-sized open-pit operation
📖 Why This Matters
In mining, over 85% of total emissions often occur *outside* the fence line—in fuel for haul trucks, electricity generation, explosive manufacturing, and contractor services. Ignoring these emissions risks regulatory noncompliance (e.g., EU CSRD), investor scrutiny (CDP, SBTi), and stranded asset planning. For blasting engineers, understanding how explosive procurement, drill rig fuel, and ore transport contribute to the carbon ledger enables smarter trade-offs—e.g., selecting low-carbon ammonium nitrate vs. higher-energy ANFO blends—without compromising fragmentation efficiency.
📘 Core Principles
Carbon footprinting rests on three pillars: (1) Emission Scopes (GHG Protocol): Scope 1 (direct combustion), Scope 2 (purchased electricity/steam), and Scope 3 (all indirect, value-chain emissions—including Category 1 [purchased goods], Category 4 [upstream transport], and Category 11 [use of sold products]). (2) Tiered Methodology: Tier 1 uses spend-based estimates (e.g., $ spent on diesel × emission factor); Tier 2 uses activity-based data (e.g., liters of diesel × kgCO₂e/L); Tier 3 uses primary supplier-specific data. (3) Boundary Setting: Mining operations must decide whether to include contractors under operational control (e.g., fleet managed by mine) or financial control (e.g., third-party haulers)—a choice that directly impacts reported Scope 3 totals and mitigation strategy.
📐 Activity-Based Emission Calculation
This formula converts physical activity data into CO₂e using standardized emission factors. It is the foundation for Tier 2 footprinting—the gold standard for engineering accuracy in mining supply chains.
GHG Emission (Tier 2)
E = A × EFCalculates greenhouse gas emissions using measured activity data and a scientifically validated emission factor.
Variables:
| Symbol | Name | Unit | Description |
|---|---|---|---|
| E | Total Emissions | kgCO₂e or tCO₂e | Greenhouse gas emissions in carbon dioxide-equivalent mass |
| A | Activity Data | L, kWh, km, t, etc. | Quantified physical flow (e.g., liters of diesel, megawatt-hours of electricity) |
| EF | Emission Factor | kgCO₂e/unit of activity | Mass of CO₂e emitted per unit of activity; sourced from IPCC, national inventories, or supplier EPDs |
Typical Ranges:
Diesel (off-road, non-bio): 2.65 – 2.70 kgCO₂e/L
Grid electricity (Australia NEM): 0.65 – 0.85 tCO₂e/MWh
ANFO production (upstream): 0.8 – 1.3 tCO₂e/tonne explosive
💡 Worked Example
Problem: A copper mine consumes 12.5 million liters of diesel annually in off-road haul trucks. Calculate its Scope 1 CO₂e emissions using the latest IPCC AR6 default factor.
1.
Step 1: Identify activity data: Diesel consumption = 12,500,000 L/year
2.
Step 2: Apply IPCC AR6 emission factor for diesel (non-bio): 2.68 kgCO₂e/L (IPCC, 2022, Table 1.3)
3.
Step 3: Compute: 12,500,000 L × 2.68 kgCO₂e/L = 33,500,000 kgCO₂e = 33,500 tCO₂e
4.
Step 4: Verify against typical range: A 100-Mtpa open-pit operation commonly reports 25,000–55,000 tCO₂e from haul truck diesel alone.
Answer:
The result is 33,500 tCO₂e, which falls within the typical range of 25,000–55,000 tCO₂e for comparable operations.
🏗️ Real-World Application
At Newmont’s Boddington Mine (Western Australia), engineers integrated carbon footprinting into blast design optimization. By mapping Scope 3 emissions from explosive suppliers (Category 1) and transport (Category 4), they discovered that emulsion explosives manufactured onsite reduced upstream transport emissions by 42% versus imported ANFO. Coupled with real-time haul truck telematics (Scope 1), this enabled a 17% reduction in blast-related tCO₂e per tonne of ore without altering burden/spacing—demonstrating how carbon metrics can co-optimize blasting and sustainability KPIs.
✏️ Student Exercise
Using the GHG Protocol Scope 3 Standard, classify the following mining activities into the correct Category (1–15): (a) Electricity purchased from state grid; (b) Diesel delivered to site by third-party tanker; (c) Drilling services contracted to Boart Longyear; (d) Transportation of milled concentrate to port via rail; (e) Employee commuting to shift change. Then calculate total Scope 1 + 2 emissions if the mine consumed 85 GWh of grid electricity (emission factor = 0.72 tCO₂e/MWh) and 9.2 million L of diesel (2.68 kgCO₂e/L).
🔧 Interactive Calculator
🔧 Open Supply Chain Carbon Footprinting Calculator📋 Case Connection
📋 Supply Chain Carbon Footprinting in Large-Scale Industrial Projects
Complex engineering requirements at scale
📋 Small-Scale Supply Chain Carbon Footprinting Implementation
Limited resources and tight budget
📋 Supply Chain Carbon Footprinting in Challenging Environments
Environmental and terrain challenges
📋 Cost Optimization in Supply Chain Carbon Footprinting
Maintaining quality while reducing costs