Mixed Fleet Retention: The Hidden Value Driver in Open Autonomy

When mining operations evaluate the transition to autonomous systems, the conversation often centres on future possibilities: increased productivity, enhanced safety, and operational efficiency. Yet for many mines, the most compelling case for open autonomy might be found not in what's ahead, but in what they already have parked in their yards.

The Reality of Mining Fleet Economics

The average large-scale mining operation runs a mixed fleet accumulated over decades. A typical site might operate Caterpillar 793s alongside Komatsu 930Es, with perhaps some Liebherr T 282s added during a recent expansion. This diversity isn't accidental—it's the result of strategic decisions made to optimize capital allocation, leverage competitive pricing, and match equipment to specific operational needs.

Each of these machines represents a multi-million dollar investment with an expected operational life of 15 to 20 years. When a mine has 50 haul trucks split across three manufacturers, with an average age of eight years, they're looking at hundreds of millions in remaining book value. The closed-stack approach to autonomy essentially asks operations to accelerate the depreciation of these assets, writing off substantial value to achieve vendor uniformity.

Understanding the Write-Off Impact

Let's put this in perspective. A fleet of 40 mixed haul trucks with an average remaining book value of $2 million each represents $80 million in assets. Under a closed-stack autonomous solution requiring fleet standardization, mines face three equally unpalatable options:

1. Immediate replacement: Write off the $80 million and purchase an entirely new standardized fleet—a capital requirement that could exceed $200 million.

2. Gradual transition: Continue operating a partially autonomous fleet for years, missing out on the full benefits of autonomy while still maintaining two separate operational systems.

3. Delay autonomy: Wait until natural fleet replacement cycles align with standardization requirements, potentially falling behind competitors in the autonomy race.

Open autonomy eliminates this dilemma entirely. Mines can retrofit their existing mixed fleet with autonomous capabilities, preserving their capital investments while achieving the benefits of automation.

Market Dynamics and Negotiating Power

The ability to maintain a mixed fleet also preserves a mine's negotiating leverage. When operations are locked into a single vendor's ecosystem, they lose the competitive tension that drives innovation and competitive pricing. Open autonomy maintains this healthy market dynamic, allowing mines to continue leveraging multiple suppliers for parts, services, and future equipment purchases. This becomes particularly relevant during expansion phases. A mine that has standardized on a single vendor for autonomy may find itself with limited options when adding capacity. Market conditions, delivery timelines, or pricing might favour a different manufacturer, but the closed-stack commitment removes this flexibility.

Mixed Fleet Retention vs. Write-Off Impact

The Operational Continuity Factor

Beyond the pure financial mathematics, mixed fleet retention offers operational advantages that are often underestimated. Maintenance teams have spent years developing expertise across different equipment brands. Parts inventories, maintenance procedures, and operational knowledge represent substantial intellectual capital that closed-stack solutions force mines to abandon.

Consider a maintenance department that has optimized its operations around servicing three different truck models. They've invested in specialized tooling, training, and spare parts inventory. They've developed relationships with multiple OEM service representatives and understand the quirks and optimal operating parameters of each model. Their expertise enables mines to adapt quickly to market shifts, equipment availability, and evolving operational needs. Open autonomy leverages this institutional knowledge rather than discarding it—turning what some see as complexity into a source of resilience that directly impacts operational efficiency.

The Integration Challenge: A Necessary Complexity

However, we must acknowledge that retrofitting a mixed fleet for autonomy isn't without its challenges. Converting vehicles from three different manufacturers means dealing with three different drive-by-wire implementations, three sets of sensor configurations, and potentially three different approaches to autonomous navigation. This complexity extends beyond the initial conversion.

Each OEM's autonomous solution may have different communication protocols, safety system implementations, and operational parameters. Integrating these into a unified fleet management system requires sophisticated middleware and careful systems engineering. When a Caterpillar autonomous truck needs to coordinate with a Komatsu unit for collision avoidance, the systems must speak a common language—something that requires additional development and testing.

The management overhead can be significant. Instead of training operators on one autonomous system, mines must maintain expertise across multiple platforms. Troubleshooting becomes more complex when issues could stem from OEM-specific implementations or integration layers. System updates must be carefully orchestrated to maintain compatibility across the mixed fleet.

While this complexity is real, it's not insurmountable—nor unprecedented. Recent progress, including the publication of ISO 23725:2024, provides a framework for enabling safe, coordinated behaviour between autonomous mobile equipment from different manufacturers. As standards like this gain traction, the barriers to integration are lowering, making cross-OEM autonomy a more attainable and less risky endeavour for forward-looking operations.

The True Cost of Open Integration

Let's be clear-eyed about what open autonomy demands. Industry estimates suggest that integrating multiple autonomous systems can add 15-25% to the initial implementation cost compared to a single-vendor solution. For a large-scale autonomous deployment, this could mean millions in additional systems integration, testing, and validation.

The operational complexities compound over time. When your fleet management system needs to orchestrate movements between autonomous vehicles from different manufacturers, each with slightly different reaction times, acceleration profiles, and sensor ranges, the traffic management algorithms become significantly more complex. Collision avoidance systems (CAS) must account for these variations, potentially leading to more conservative operating parameters that impact productivity.

Consider a real-world scenario: A Liebherr autonomous truck approaching an intersection with a Caterpillar unit. Their collision avoidance systems, developed independently, might have different safety buffer calculations and response protocols. Ensuring safe, efficient interaction requires additional integration layers and extensive testing—costs that don't exist in a homogeneous fleet.

Calculating the Net Benefit

Despite these integration challenges, the financial mathematics still favor mixed fleet retention for most operations. Even with a 25% premium on integration costs, the avoided write-offs dwarf the additional expense. If open autonomy integration adds $20 million to a project that preserves $80 million in fleet value, the net benefit remains compelling. Of course, these figures are directional and should be evaluated within each operation’s specific context. Risk-adjusted modelling, including downtime scenarios and support contingencies, is essential. However, even under conservative assumptions, the capital preservation enabled by open autonomy often outweighs the integration premium—especially when paired with phased deployment strategies that mitigate risk.

Moreover, many integration costs are one-time investments. Once the systems are properly integrated and tested, the ongoing operational overhead, while significant, is manageable. Modern mining operations already handle complexity across multiple systems—from various drill manufacturers to different explosive systems to diverse processing equipment. Adding autonomous system diversity to this mix is an incremental, not exponential, increase in complexity.

Short-Term Necessity or Long-Term Advantage?

Critics might argue that mixed fleet retention is merely a transitional benefit—important for the near term but diminishing in value as mines eventually standardize their fleets through natural replacement cycles. In these instances, open autonomy can allow that transition to occur on the mine’s terms, enabling a gradual, economically rational evolution, preserving optionality rather than an overhaul. However, the mining industry's history suggests that fleet diversity is not a temporary condition but a persistent operational strategy.

Even as autonomy gains traction, mixed fleet management will remain and for good reasons—driven by site-specific constraints and needs, procurement timing, geographic factors, service availability and the need for operational agility in volatile markets. Open autonomy doesn’t prevent standardization; it simply doesn’t require it.

That said, we must acknowledge that some operations might genuinely benefit from standardization. A new mine starting with a clean sheet might find the simplified operations of a single-vendor autonomous solution appealing. Smaller operations might lack the technical resources to manage multi-vendor integration effectively. For these cases, closed-stack solutions offer legitimate value. But for the majority of established mining operations with significant invested capital in mixed fleets, the integration complexity of open autonomy is a manageable challenge compared to the alternative of massive asset write-offs.

The Innovation Timeline

While long-term innovation flexibility is undoubtedly valuable, it's worth questioning when these innovations will materially impact operations. The next breakthrough in autonomous mining might be five years away—or fifteen. The closed ecosystems may iterate faster within their own stack, they often limit the scope of innovation to what fits their proprietary roadmap. Open autonomy, on the other hand, fosters a broader innovation ecosystem where third-party developers, research institutions, and integrators can contribute breakthroughs that benefit the entire industry. Decoupling autonomy from equipment brands allows miners to adopt emerging technologies as they mature, without being limited by the timeline of a single vendor.

In the meantime, mines need to generate returns, control costs, and maintain competitiveness. The ability to preserve existing fleet investments while implementing autonomy provides immediate, quantifiable value that funds the adoption of future innovations.

Conclusion: Value in Hand

The debate over open versus closed autonomy often focuses on future possibilities, but for many mining operations, the most compelling argument lies in present realities. The ability to retain and autonomize mixed fleets doesn't just preserve capital—it maintains operational flexibility, leverages existing expertise, and provides a pragmatic path to automation that aligns with how mines actually operate.

Yes, managing multiple autonomous systems adds complexity. Integration costs are real, coordination challenges exist, and operational overhead increases. But these are engineering problems with engineering solutions—challenges that mines routinely solve across their operations. The alternative—writing off hundreds of millions in productive assets—is a financial problem with no solution other than accepting the loss.

While the promise of future innovation and vendor flexibility remains important, the immediate value of mixed fleet retention might be the factor that tips the scales for operations evaluating their autonomous strategy. In a capital-intensive industry, the freedom to preserve existing investments while achieving autonomous capabilities isn't just a benefit or a strategy—it’s essential.

The question isn't whether long-term flexibility or mixed fleet retention is more important. It's whether mining operations can afford to sacrifice one for the other. Open autonomy's answer is clear: they shouldn't have to. The complexity is manageable; the stranded assets are not.