In-pit Crushing and Conveying (IPCC) as a driver of reduced mining costs and reduced emissions

Background

In a time where:

(a) open pits are getting deeper requiring lower mining cost solutions, and

(b) there is increasing pressure on mining companies to reduce carbon emissions

In-pit crushing and conveying (or IPCC) is a potential solution for both issues. And when we say potential, we mean that it will not work for every case. However, in those cases where it makes sense, the economic and environmental benefits can be significant.

Snowden, and its IPCC team, has completed at least 40 IPCC studies worldwide and is well placed to help you understand, at a desktop through to pre-feasibility level, whether IPCC might be of benefit to your operation.

What is IPCC?

The intent of IPCC is to convert as much of your material haulage from trucks (and their associated manning, fuel, maintenance, tyres and capital cost) to conveying.

IPCC reduces capital and operating costs by a combination of:

• Switching manning from truck operators and maintenance to a single, more automonous system requiring less personnel.
• Replacing diesel consumption with electricity.
• Reducing the number of trucks you need in the mine (both peak and replacement).
• Reducing the associated ancillary equipment fleet.

For these benefits, there is an upfront capital investment and an ongoing operating cost associated with the IPCC system and changes required to your mine plan. In order to convey material, it must first be crushed or sized. IPCC can be completed for both ore and waste, although the benefit with ore is typically greater as crushing waste is “dead money”.

What are the potential benefits?

Through the numerous studies completed into IPCC, Snowden has found the following typical results:

• Cash cost reduction of between US$0.18/t and US$1.00/t
• Best Net Present Cost (NPC) improvement – US$800m (@9% discount)
• Typical truck savings from 20 to 60% of fleet
• Typical reduction in manning – averages 6.5 persons per truck saved
• Typical reduction in ancillary equipment – 30%
• Reduction in infrastructure costs associated with workshops
• Overall capital for long life mines is either near neutral or in favour of IPCC when truck replacements are considered.
• Reduction in on-site carbon emissions by up to 50% depending on power source.

What are the types of IPCC?

There are four main types of IPCC:

1. Fixed ex-pit (EPCC): Where a crusher is located outside the pit rim and is used to reduce long ex-pit hauls.
2. Fixed in-pit: Where a crusher is located inside the pit rim, at a fixed location (final wall) to increase the haulage savings from EPCC.
3. Semi-mobile: Where a crusher is located inside the pit rim, and moves semi-regularly to new positions to maximise the haulage savings.
4. Fully-mobile: Where the crusher (sizer) is directly loaded by a shovel, eliminating the need for trucks.

The planning complexity increases between each type of IPCC, with fully mobile being generally the most complex in metalliferous mines. Determining the best option for your operation(s) is key to the potential for successful implementation.

What does IPCC do to your mine plan?

The impact on IPCC depends on the type of IPCC system being implemented. However, the types of impacts include:

• Pit re-design: Unless you are using EPCC, your pit will need some redesign to accommodate the crusher pocket and conveying route. The conveyor may have a dedicated route, or be placed alongside an existing (but widened) haul route. Where possible the conveyor route should be as straight as possible to minimise transfer points. Additionally, you may need to adjust your pit stages to provide connections between phases or pits that minimise the number of crusher moves.
• Scheduling: You may need consider additional material movement in your schedule, or optimise your schedule to maximise the tonnage reporting to your IPCC system.
• Waste dumping: IPCC waste dumps require detailed planning and can be difficult to integrate into existing operations. Often trucked waste will be required to prepare the IPCC waste dump ahead of commencement. The ability to manage multiple waste types in a dump is limited and complex waste dump shapes must be avoided (as they will increase the number of conveyor movements and reduce system capacity).

Caption: A “best-case” mine and waste dump design for radial IPCC.

Will IPCC work for your mine?

The benefits of IPCC depend on the specific conditions of your mine. IPCC tends to favour:

1. Longer hauls: Usually a minimum cycle time of at least 15 mins (in a pit stage or group of pit stages) is required, depending on the price of generated electricity.
2. Tonnage: Usually a minimum of 20 Mt/a is required to be moved from a pit stage (or group of connected pit stages). This needs to be separated by ore and waste (as they will typically use different IPCC systems).
3. New project or operation where existing truck fleet does not need to be replaced.
4. Low electricity unit costs and/or
5. High fuel costs
6. High labour costs
7. Minimal rock types: IPCC is more challenging when you have to blend ore, or manage waste materials (such as acid generating rock).
8. Lower rock strengths: This enables a greater throughput to crusher/sizer ratio.
9. Organisation needs to be open to change: IPCC often fails due to the inability of leadership to accept the necessary operational paradigm changes to make it successful.
10. High priority on reducing Carbon emissions

Of course, not all these items need to be favourable for IPCC to be of benefit, but the more the better!

How can Snowden help?

Snowden has developed the expertise required to optimise mine designs and schedules for the application of IPCC. The Snowden IPCC team includes experts in IPCC strategy, IPCC engineering and mine planning.

Our Team

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We specialise in desktop, scoping and PFS level assessments of IPCC potential for new or existing mines. In an initial assessment, we will:

• Review a base case (truck only) mine plan developed by you
• Identify a potential IPCC strategy(s) that may lead to a positive economic/environmental outcome
• Assess the potential risk factors that would limit the IPCC potential
• Assess the impact of the IPCC strategy on the mine plan
• Estimate the potential truck savings resulting from the IPCC strategy
• Estimate the cost (operating and capital) for the proposed IPCC solution (in conjunction with IPCC suppliers)
• Evaluate the potential economic and environmental benefit through differential analysis to the base case plan.

Such assessments can typically be completed within a month, depending on the complexity and the detail required.

Snowden can then assist with mine planning and detailed IPCC strategic support if your project progresses beyond initial study level.

Contact us today at snowden@snowdengroup.com if you are keen to explore the potential benefits of IPCC at your mine.