The primary driver of open-pit emissions is cycle volume: the total number of truck-load cycles required to move ore and waste through a given mine plan
The System Pressure
The structural tension in open-pit decarbonization is straightforward: the largest emission source is also the hardest to replace. According to Equinox Gold’s 2025 sustainability reporting, diesel-powered mobile equipment accounts for approximately 70% of corporate greenhouse gas emissions across the portfolio. If that figure is directionally representative of open-pit gold operations more broadly—and the underlying physics of bulk material movement suggest it likely is—then the decarbonization system pressure sits squarely on the mobile fleet, not on purchased electricity.
This matters for how Mining Operations Directors frame internal decarbonization conversations. Renewable energy procurement, energy certificates, and grid switching can collectively address residual Scope 2 exposure, but they leave the dominant emission source structurally untouched. Meaningful progress against any 2030 target requires attacking diesel consumption directly.
The complicating factor is growth. When a producer acquires new assets mid-cycle, each new operation imports its own energy profile, mine plan maturity, and fleet configuration. The resulting aggregate emissions figure in any transitional year is not a clean performance signal—it is a composite of base performance, integration-phase energy demand, and inherited asset characteristics. Reading that number as a steady-state indicator mischaracterizes what is actually happening in the system.
The Drivers, Dependencies, and Constraints
The primary driver of open-pit emissions is cycle volume: the total number of truck-load cycles required to move ore and waste through a given mine plan. Payload capacity per cycle is the most direct mechanical lever on that volume. Equinox Gold’s reporting describes a transition to higher-capacity Caterpillar 793-8 haul trucks at its Greenstone operation, with an attributed saving of 161,000 tCO₂e in 2024. The mechanism is not a technology breakthrough—it is scale: more material per cycle means fewer engine-hours for equivalent throughput, reducing cumulative diesel burn. These figures come from a single company report and have not been independently verified, but the underlying mechanism is well-established in haul cycle analysis.
Load optimization represents the low-capital complement to fleet upgrades. A reported initiative at Los Filos improved average load volumes by 10 tonnes per cycle, saving an estimated 167,800 litres of diesel. The impact per tonne moved is modest relative to fleet-replacement programs, but so is the implementation cost—dispatch system calibration, shovel-truck matching improvements, and operator behavior protocols, rather than capital-intensive equipment replacement.
Purchased electricity is the second major emission category. The dependency here is grid composition in each operating jurisdiction, which is largely outside a site operator’s direct control. Equinox Gold’s reporting describes its Brazilian operations—Santa Luz and Fazenda—as sourcing 100% of electrical power from renewables under wind purchase agreements. Where direct power purchase agreements are not commercially available, the portfolio uses renewable energy certificates to claim the carbon attribute of clean generation. The source reports 10% renewable energy share across the total portfolio, making clear that the Brazilian benchmark is not yet the portfolio norm.
One dependency that often escapes operational focus is the emissions profile of assets in care and maintenance. The Los Filos heap leach complex in Mexico reportedly contributed 59% of corporate market-based Scope 2 emissions during 2025 despite being in a care and maintenance configuration. Heap leach operations continue drawing grid electricity to maintain solution management, pump systems, and processing circuits throughout residual leaching cycles—regardless of active mining. For operations directors managing sites with similar process configurations, this is a material planning consideration: suspending active mining does not proportionally reduce electrical demand or Scope 2 exposure.
Open Dependencies
The most significant unresolved dependency in this system is fleet electrification at production scale. The source acknowledges that large-capacity haul truck electrification has no commercially scalable zero-emission alternative at the scale required for major open-pit operations as of the 2025 reporting period. Battery-electric haulage technology continues advancing, with several OEM development programs underway, but the timeline for proven deployment at 200-tonne-plus payload capacity in production environments remains genuinely uncertain. Until that constraint resolves, the decarbonization system is structurally dependent on diesel efficiency improvements rather than diesel elimination.
The baseline methodology also introduces an open dependency. Equinox Gold’s 25% reduction target is measured against a business-as-usual forecast, not an absolute historical reference. This approach is defensible—it accounts for production growth—but it means the target is partially a function of how the BAU projection is constructed and updated as acquisitions close. The pending Orla Mining acquisition, described in the source as expected to close in Q3 2026, will require another baseline recalibration before the 2030 target can be tracked against a stable reference. Whether that recalibration will be transparent and comparable to the current baseline is not addressed in available reporting.
Scope 3 emissions are entirely absent from the current framework. The source notes this is common across mid-tier gold producers, but it means the reported footprint excludes upstream supply chain emissions—including manufacturing of the mining equipment itself—and downstream processing. Operations directors benchmarking against peer reporting should confirm this exclusion boundary before drawing direct comparisons.
The Operating Exposure for Mining Operations Directors
The operational consequence of this system is that fleet capital decisions carry a dual financial weight: production performance and emissions trajectory are coupled at the truck-selection level. A fleet upgrade program justified on productivity grounds—more tonnes per shift, lower cost per tonne moved—also functions as the most material decarbonization intervention available to site-level management. These two decision rationales should be presented together in capital appropriation requests rather than separately.
Load optimization programs are underutilized in this context. The low-capital nature of dispatch calibration and shovel-truck matching makes them accessible within operating budgets rather than capital budgets. If the Los Filos figures cited in the source are directionally accurate, optimization-driven diesel savings at a single site can exceed 150,000 litres annually without equipment replacement—aggregating to material avoided cost across a multi-site portfolio at current diesel prices, independent of any decarbonization framework.
Heap leach operations require specific attention to Scope 2 management during operational transitions. Care and maintenance configurations that extend residual leaching cycles while suspending active mining can produce counterintuitive emissions concentrations—high Scope 2 relative to gold output—that inflate reported intensity metrics. Operations directors managing heap leach assets through these transitions should understand how their site’s electrical demand profile will appear in corporate sustainability reporting, and whether renewable certificate coverage or grid switching options can be accessed during those periods.
Grid dependency mapping is increasingly relevant as renewable purchase agreement markets develop across Latin America and other major mining jurisdictions. The Brazilian precedent described in the source—100% renewable power at two operations through wind contracts—is a procurement model, not a technology model. The question for each jurisdiction is whether the commercial and regulatory conditions for equivalent agreements exist, not whether the technology does.
Signals the System Is Shifting
Three indicators would confirm that open-pit decarbonization is moving from efficiency improvement toward structural change.
First, fleet electrification announcements with deployment timelines and payload specifications from major OEMs. Caterpillar, Komatsu, and others have development programs for large-format battery-electric haul trucks, but confirmed production deployments at 150-tonne-plus payload with commercial operating data would mark a genuine system shift rather than a development roadmap signal.
Second, renewable power purchase agreement penetration in non-Brazilian Latin American mining jurisdictions—Mexico, Peru, Chile—where grid composition remains mixed and direct clean power contracts are not yet standard. Progress in those markets would expand the addressable Scope 2 footprint beyond the current 10% portfolio-wide renewable share.
Third, emissions intensity trajectory across two or three consecutive reporting cycles for companies undergoing acquisitive growth. A portfolio-level intensity figure declining from its post-integration baseline—not the absolute tonne figure, which will move with production volume—would indicate that efficiency and procurement programs are outpacing growth-driven emissions increases. That trajectory, rather than any single annual avoided-emissions claim, is the indicator worth tracking for producers targeting credible 2030 progress.
Sources
- Com — Equinox Gold Emissions Reduction: Decarbonisation Progress in 2025 (Link)
