To IPCC or not to IPCC?

We live in a mining industry of ever deepening pits, rising waste-to-ore ratios, and increasing pressure to reduce carbon emissions and other environmental impacts. Although by no means suitable for every mine, in-pit crushing and conveying offers a solution to all of these issues and, where it makes sense, the economic and environmental benefits can be significant.

By Jonathan Rowland

In-pit crushing and conveying can offer significant economic and environment advantages. Pictured: Terra Nova Technologies modular primary gyratory crushing station at a large copper mine in Chile.

In-pit crushing and conveying (IPCC) refers to “a system that combines crushing and conveying technologies to transport material within a mine site as an alternative to traditional truck haulage,” explained Paul Emerson, director of business development at Terra Nova Technologies. The idea is that “conveying material is more efficient – in terms of energy and cost – than trucking but, in order to convey material, it must first be crushed, as whole-rock feed will damage the conveyors,” added Phil Morriss, an independent mine engineering consultant and specialist in IPCC analysis.

As a term, it was “created for mining systems with a crushing plant – preferably semi-mobile or fully mobile – located directly in the pit,” said Rico Neumann, chief mine planning engineer at TAKRAF GmbH. “But the meaning has become more general over time. Nowadays, IPCC tends to mean one or more primary and/or secondary crushing plant(s) in a pit, at pit rim or other nearby location, with a downstream conveying system feeding waste dumps, commodity stockpiles, or intermediate bins for further transport and/or processing.”

More often used to handle ore, IPCC can also be used to handle waste streams, although the economics here are more challenging. Yet, as waste-to-ore ratios increase and haulage cycles get longer, “waste IPCC can offer the chance to decrease costs and enable the economic extraction of ore at greater depths,” said Morriss.

Three types of IPCC
There are three main types of IPCC system, which are defined by the maneuverability of the crushing station. The least mobile option is a fixed IPCC system, wherein the crushing station “is typically located near the pit rim and is (as the name implies) fixed for the life of the mine,” said MMD’s Puckett. “Trucks then haul material to the station for efficient long haul by conveyor.”

Semi-mobile IPCC systems involve “portable crushing stations that are frequently relocated closer to the face, as it progresses, by ancillary equipment, such as bulldozer or transporter,” Puckett continued. These periodic relocations, which typically occur either quarterly or biennially, help keep truck haulage distances and economics down. “The crushing station is mounted on moveable pontoons or skids to facilitate this repositioning,” added Terra Nova’s Emerson, “with a series of bench conveyors and ramp conveyors then transporting material out of the pit.”

The final – and perhaps truest – iteration of the IPCC concept is the fully mobile system. Here the crushing station is equipped with “permanently attached, powered tracks or wheels that allow it to follow the face excavation equipment,” said Puckett. “Fully mobile systems replace the use of trucks in primary excavation,” added Nicholas Russell, principal mechanical engineer at Worley. “Rather, shovels, excavators, or loaders feed directly onto a conveyor system via a dump hopper with a sizer or crusher.”

Selection between systems “depends on factors such as mine layout, material characteristics, and production targets, aiming to balance cost, operational efficiency, and environmental impact,” concluded Terra Nova’s Emerson. Mines may also “transition from semi-mobile to fully mobile operation, or utilize both,” noted Worley’s Russell.

In terms of the equipment required, IPCC systems generally combine several proven technologies, according to Tarrant Elkington, general manager at Snowden Optiro.

  • Crushing: Sizers, double roll crushers, high-bypass jaw crushers, or gyratory crushers, with selection dependent on the strength of the material to be crushed and its particle size distribution.
  • Conveying: Overland conveyors, generally fixed, and track- shiftable conveyors for waste materials, are usual for fixed and semi-mobile system, Modular conveyors are more frequently used for fully mobile systems.
  • Spreading/discharging: Some form of spreading will be required for waste material, using mobile equipment that can transfer material from the conveyors and discharge safely onto the waste dump.
Bulk ore sorting (BOS) systems complement IPCC systems, providing analysis, sorting, and separation of ore in the pit, based on natural variations within orebodies. Pictured: a MMD BOS application.

Benefits of IPCC: Deeper pits and operating costs
Returning to our starting point and those pressing challenges facing surface mines today, IPCC systems “offer a multifaceted solution to address these challenges,” said Terra Nova’s Emerson. “While initial capital investment is higher, IPCC systems can offer significant long-term operational cost savings through reduced fuel, labor, and maintenance expenses.”

“Capital costs are high,” agreed Phil Morriss, “but in most studies, they are close to the truck purchase and replacement cost over the life of the project, while operating costs are generally considerably lower than trucking alternatives: typical savings are 25% to 40% of a truck-and-shovel operation for the same tonnage.” Much of this benefit derives from the fact that “conveying offers a more energy- and cost-efficient way of transporting material up hill, as conveyors do not have to carry the dead weight of the empty truck.”

Conveyors “can also climb steeper gradients than trucks,” said MMD’s Puckett, an important factor as mines descend to ever deeper depths. “Together with the reduced bench width needed for conveyors, the use of conveyors can shape a mine very differently to a conventional long haul truck-and-shovel operation. Steeper mines also minimize the amount of overburden that needs to be removed before getting down to the paydirt, not only helping the mining operation, but also subsequent land reclamation.”

There is also an efficiency bonus to be gained from adopting IPCC, even when mining operations still include some truck haulage. “Reducing truck haulage distance with semi-mobile and fixed IPCC installations means trucks spend more time as a percentage dumping and being loaded, increasing the production rate per truck, and reducing truck numbers compared to full truck-and-shovel operations,” explained Puckett. This flows on to reduced maintenance workshop needs and downtime, noted Snowden Optiro’s Elkington, with trucks able to shift more material between stoppages. IPCC systems can also mitigate, either partially or completely, the need to purchase new trucks.

Yet IPCC is not a “silver bullet,” as TAKRAF’s Neumann pointed out. “Deep pits present a real challenge when it comes to relocating the crushing plant into the pit. And as conventional 18-degree conveyors require straight ramps in a normally curved pit wall, additional cuts can increase the generation of waste material. Tunneled solutions might be an option (but these are expensive) or special steep-angle/suspended conveyors that are independent of access/haul ramps. A chain of several mobile conveyors, closely fitting along the pit wall, has also been looked at, but this creates other unique challenges in terms of numerous transfer points, increased power consumption, and potential interference with other infrastructure.”

Benefits of IPCC: Environmental impact
The energy efficiency of electrically powered conveyors, especially when paired with renewable energy sources, “offers significant reductions in carbon footprint when compared to traditional haul trucks and thus aligns with miners’ environmental and sustainability goals,” said Terra Nova’s Emerson. Indeed, when coupled with hydropower, IPCC can offer “near 100% reduction on CO2 emissions per liter of fuel saved,” added Phil Morriss. “Other power sources deliver lower reductions with coal-fired power offering the least or near-zero reduction.”

Because conveying is “more energy efficient than trucking, there is also potential to reduce the overall energy required by the mine, although this may be partially offset by the energy required for crushing in waste IPCC,” continued Morriss. It is a benefit that is “only compounded over longer haul distances,” added TAKRAF’s Neumann.

Removing (or reducing the number of) truck diesel engines from the pit also means that “mines become cleaner and quieter, with less dust and less non-carbon emissions. Fully mobile systems typically eliminate trucks, so noise pollution and dust are reduced considerably, while in semi-mobile and fixed installations, truck haulage is limited to the pit. With fewer trucks generating less dust, the need for dust suppression is reduced, lowering water consumption in the mine,” said MMD’s Puckett. There is also “better control of material handling and reduced spillage, further minimizing the ecological footprint,” added Terra Nova’s Emerson.

Benefits of IPCC: Health, safety and labor
An additional benefit of IPCC relates to mine safety, which can be “drastically enhanced by reducing the number of trucks and associated risks of collisions and accidents,” said Emerson. And it is not just the number of trucks that is reduced: “with less trucks, there is less need for ancillary services, such as graders, bulldozers, and water trucks,” commented Puckett, with Phil Morriss noting a typical achievable reduction of 20% to 30% in grader and dozer requirements.

IPCC operations also reduce the number of people in the pit and the cost of labor. “Depending on whether autonomous or manual trucking is used, manpower can be reduced by 2.5 to 6.5 persons per truck removed,” said Morriss. “This is offset by the manning to operate the IPCC, but this is typically low and largely dependent on scale; hence the larger the tonnage being moved, the higher the net savings in manpower.”

Innovations in fully mobile conveying technology, such as the Super Portable conveyor from Terra Nova Technologies (pictured), enable seamless integration with mining operations that have varying needs and dynamic mining plans.

Advancing in IPCC solutions
All developments “ultimately have one aim,” said TAKRAF’s Neumann, kicking off this section of the discussion, “to improve performance and cost models so IPCC comes down on the winning side in trade-off comparisons with other possible material handling systems. In this regard, we have, over the years, seen developments in the layout and design of semi-mobile systems, including the use of modular equipment, designs that reduce civil works, and modifications to improve the speed of crusher relocation to reduce downtime.”

Maintainability is “another key issue,” continued Neumann. “Careful and timely preventative maintenance is important for high technical availability. And we shouldn’t forget various developments in the crushing equipment itself, with manufacturers always seeking to increase safety, support higher-capacity throughputs and performance, and reduce power consumption and operating costs.”

“We are excited to see the development of new technologies that assist or complement current IPCC operations in the pit,” said MMD’s Puckett. For example, “our fully mobile Surge Loader (FMSL) acts as a mobile storage bunker between the loader (shovel, front-end loader, screens, etc.) and the truck. This decouples the conventional relationship between the loader and the truck fleet, improving the efficiency and safety of both in semi-mobile and fixed IPCC operations. Looking to the future, the FMSL may also assist with the adoption of smaller electric truck haulage and truck automation.”

Another technological development impacting IPCC is bulk ore sorting (BOS), which “provides in-pit analysis, sorting, and separation of ore, as well as rejection of waste, based on natural variations within orebodies,” continued Puckett. Sorting and discarding waste before downstream processing steps is “already seeing benefits in some operations,” he concluded. “We are seeing up to 20% uplift in grade, 10% less water and energy usage, as well as lower operating costs and an increase in process system capacity.”

“It sounds counterintuitive but I’m excited for the advancement of autonomous, battery-electric, circa-30 t dump trucks,” Worley’s Russell said, picking up on Puckett’s comments. “These are perfect to be paired with a ‘sporty’ semi-mobile dump, crusher and conveyor solution and various forms of BOS. This is most efficient when done on conveyor, while doing it closer to the pit significantly saves in multiple ways, including operating cost, power consumption, disposal costs, and water consumption.”

More prosaically, traditional conveyor technology is also advancing, concluded Puckett. “Traditional conveyor technology routes are commonly restricted to straight lines or very large curves; however new technologies are reducing these restrictions. With newer technologies, conveyors are becoming more versatile, facilitating IPCC deployment in much more challenging operations.”

And then, there’s digitalization, which is also “transforming IPCC systems,” according to Terra Nova’s Emerson, “offering advantages in efficiency, safety, sustainability, and decision-making. Key impacts here include real-time monitoring and control of operations, enabling instantaneous adjustments and predictive maintenance, as well as improved environmental monitoring and compliance monitoring through tracking dust, noise, emissions, and energy consumption. Digitalization also aids “integration with broader mine operations for better planning, coordination, and bottleneck reduction, as well as remote monitoring and control capabilities, minimizing human presence in high-risk areas, continued the Terra Nova expert.

Is IPCC right for you?
For all its benefits, IPCC is not appropriate for all mine sites. Questions to ask include:

  • What is the expected life of mine? IPCC typically requires substantial upfront investment and is more suitable for long-life operations.
  • What annual tonnages are being considered? IPCC generally benefits from higher throughputs to offset/recover the high capital cost quickly (although this is not a must).
  • What are the typical truck haulage cycle times/distances for the material being considered for IPCC?
  • How will the IPCC system be integrated with existing operations and infrastructure, and what is the compatibility with future mining plans and processing facilities?
  • Are you considering IPCC for waste or ore? Waste crushing cost is dead money, and hence has a higher operating cost hurdle to overcome than ore, where crushing is completed for trucking operations.
  • What are the material characteristics, such as hardness, moisture content, and lump size, which influence the selection of primary crushing type, and thus affect the feasibility of the IPCC system?
  • Feed complexity: IPCC systems are preferred when the feed is stable and simple. When complex material management is required, e.g., blending ores or acid material management for waste, the benefits of IPCC can diminish.
  • Haul trucks face problems when entering pits on seasonally wet, muddy inclined haul roads. Could this be a major advantage for conveying lines?
  • What is the unit power cost versus diesel? High power costs diminish the cost differential; high diesel prices will improve the attraction of IPCC.
  • What discount rate is being applied to an investment
    decision? High (+12%) rates make investment in IPCC systems difficult to get over the line.
  • What form of electrical power is available and, maybe more importantly, is this available in sufficient quantity to sustain such an operation?
  • Does the mine have the technical and operational expertise required to manage and maintain IPCC systems effectively, or can they obtain those personnel?

Ultimately, “no application will tick all the boxes and there are many trade-offs and unique characteristics of each site that need to be considered to determine whether IPCC could/should be applied,” said Snowden Optiro’s Elkington. “At the highest level, a company can get a screening analysis undertaken by competent consulting groups. If this screening looks positive, a desktop study can be undertaken. In simple terms, test the water first, and then be prepared to have the mine planning reviewed to move forward with scoping, pre-feasibility, and feasibility level studies.”

And this points to an important fact picked up by Worley’s Nicholas Russell. “IPCC doesn’t just ‘impact’ mine planning; it is a fundamental driver in the mine model, and changes how a mine plan is developed and maintained. IPCC influences the block cost model and thereby the ultimate pit limits. The pit geometry needs to include allowance for ramp conveyors. Balancing ore-to-waste ratio and getting consistent ore grades are mid-term mine planning activities, not short-term. Close coordination is required between the mine planning team and the materials handling design team to achieve a flexible conveyor design that suits the pit geometry and gives the mine planning team the tools they need to develop, modify, and improve the mine plan.”

The pit layout and design for IPCC is “greatly influenced by the conveyor routing and infrastructure to ensure versatile and efficient material movement during each mine phase,” added MMD’s Puckett. “Pit geometry, bench heights, and ramp configurations must accommodate conveyors, sizer stations, crossing points, and material transfer points.”

The aim is to ensure “uninterrupted material flow and operational continuity,” Puckett continued. “As the mine progresses, the expansion of the conveyor network and the relocation of crushing stations must be carefully sequenced to maintain seamless operations. To facilitate this, it may be necessary to implement multiple smaller stations and conveyors strategically, ensuring continuous production to meet extraction targets. Additionally, contingency plans must be devised to address any unforeseen challenges and guarantee operational continuity throughout the mining lifecycle.”

The future of IPCC?
IPCC for ore applications “will continue to be attractive, given that you are only really incurring the cost of the conveying system,” said IPCC expert, Phil Morriss. “It just makes sense to bring the crusher as close to the source as possible. And as more mines implement renewal energy solutions, and equipment suppliers find innovative solutions to reduce the capital costs of these systems, we expect that IPCC will become more attractive.”

The global push for sustainability and environmental responsibility means the “integration of IPCC systems with renewable energy sources could become increasingly prevalent,” agreed Terra Nova’s Emerson. “However, widespread adoption of IPCC systems faces challenges, such as the difficulty of implementing them in existing mines designed for truck-and-shovel operations. Additionally, the need for versatile and mobile IPCC systems that can adapt to dynamic mining plans, as well as the limitations of existing conveying technologies for steep pit walls, remain obstacles.”

In the short term, “I anticipate a focus on flexibility, modular designs, and customization of existing technologies to tailor IPCC systems to the specific operational, environmental, and economic objectives of each mine,” continued Emerson. “Meanwhile, the integration of AI-driven technology represents a promising frontier for IPCC systems, offering the potential for smarter, safer, and more efficient mining operations in the future.”

For TAKRAF’s Neumann, this could open opportunities for mine plans that integrate the benefits of IPCC with truck-and-shovel operations. Such systems offer “high flexibility in the pit area, which is often restricted, as well as the least amount of waste rock per ton of ore, combined with the safe and continuous operation of a conveying system boasting high availability and utilization, together with low operating costs. This is the future of IPCC.”

“While the journey towards widespread adoption of IPCC systems in the mining industry may present challenges, the opportunities and benefits they offer in terms of efficiency, sustainability, and cost savings are undeniable,” continued Emerson. “Ultimately, successful implementation of IPCC systems will require close collaboration between equipment suppliers, mine operators, and engineering firms, facilitating the sharing of best practices, innovation, and technology development.”

The fully mobile Surge Loader™ from MMD decouples loader and truck operations, improving the efficiency and safety of both, in semi-mobile and fixed IPCC operations.

This was echoed by MMD’s Puckett: “New innovations emerging in mining, especially developments in the pit, will significantly improve the efficiency and sustainability of IPCC operations. However, these innovations only become meaningful when all the parts of the process work harmoniously together, bringing both upstream and downstream benefits.”

New collaborations among stakeholders, including technology providers, mining companies, and researchers, are “paramount to an effective solution,” continued Puckett. “Involving all those involved in the mining value chain is important to ensure the solution accommodates the different undertakings present in a mine, from mine managers through to operators and maintenance crew. Without this involvement, the operation and integration of the equipment within the application may not be fully realized, and its potential never reached. By taking a holistic view of the whole value chain, together with collaboration and modularity, mines can not only enhance efficiency, but also increase agility and operational resilience in the face of evolving challenges.”

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