Understanding depreciation for mining equipment

Mining operations combine mobile plant, fixed processing infrastructure and purpose-built installations that operate as integrated systems. Assets are often customised to a specific ore body, mine plan or production method, rather than selected from off-the-shelf industrial equipment.

Several factors add complexity:

As a result, mining assets rarely align neatly with generic depreciation categories or assumptions that might be suitable in other industries.

For depreciation purposes, mining equipment generally falls into three broad groups, each with different risks around classification.

Mobile plant

Mobile mining equipment is typically treated as plant and equipment and may include:

These assets are usually easier to identify but still require careful assessment of how they are used, upgraded and rebuilt over time.

Fixed plant and processing equipment

Fixed plant commonly includes:

Core processing assets such as crushers, conveyors and beneficiation equipment are typically treated as plant and equipment for depreciation purposes. However, complexity can arise where these systems are integrated with permanent structures or foundations, which may qualify as capital works.

Infrastructure-linked equipment

This category is where boundaries most commonly blur. Examples include:

In mining, equipment is frequently constructed as part of a larger system rather than installed independently. Understanding where equipment ends and capital works begin is critical.

The distinction between Division 40 plant and equipment and Division 43 capital works is central to mining depreciation.

Why the distinction matters

Plant and equipment is depreciated based on effective life, while capital works deductions are spread over much longer periods. Misclassification can significantly alter the timing and profile of deductions across a project’s life.

How misclassification occurs

Common issues include:

In mining, long-life structures often support or house equipment. These components may qualify as capital works even though they serve a processing function.

Long-life and composite assets

Many mining assets are built as composites, combining structural, mechanical and electrical elements. Breaking these down correctly requires an understanding of how the asset was designed, constructed and intended to operate.

In mining, depreciation does not hinge on paperwork alone. Actual use drives outcomes.

When depreciation starts

Depreciation generally begins when an asset is first used or installed ready for use. In mining, this may occur:

Assuming a single commissioning date across an entire site can be misleading.

Shutdowns, upgrades and replacements

Mining operations routinely involve:

These changes can alter depreciation profiles over time and require adjustments that are often missed if assets are treated as static.

Why real-world use matters

An asset’s effective life and depreciation treatment should reflect how it is actually used, not how it appears on a purchase order or asset register.

Across mining projects, several recurring issues arise.

Bundled assets

Large contracts often bundle multiple asset types together. Without proper separation, depreciation may be applied too broadly or too conservatively.

Generic effective lives

Applying standard effective lives without considering operating conditions, duty cycles or rebuild practices can misrepresent asset consumption.

Missed adjustments over time

Mining assets evolve. Failing to review depreciation as assets are modified, relocated or rebuilt can lead to outdated schedules that no longer reflect reality.

Desktop or templated depreciation schedules are rarely suitable for mining operations. Mining assets are not interchangeable, even across similar sites.

A site-specific assessment allows for:

Understanding the physical layout, installation method and operational role of each asset is essential to achieving accurate and compliant outcomes.

To illustrate how depreciation applies in a mining context, consider a mine site where a tax depreciation schedule was prepared following a site-specific assessment.

The operation relied on a mix of mobile plant and fixed processing equipment, including magnetic separators, conveyors, underground haulage trucks, excavators and dozers. These assets formed part of an integrated production system and were assessed individually based on how they were constructed, installed and used on site.

The table below outlines ten plant and equipment assets identified during the assessment, showing their original value at purchase, first-year depreciation deductions and cumulative deductions over the first five years of operation.

Mining depreciation deductions – example

Depreciation deductions in this example were calculated using the diminishing value method. Figures are illustrative only and will vary depending on asset classification, effective life, installation and operational use.

Across these ten assets alone, the total capital value assessed was approximately $13.4 million. Based on their classification and effective lives, depreciation deductions of $1.86 million were identified in the first financial year. Over the first five years of operation, cumulative deductions exceeded $6.6 million.

Importantly, these outcomes were not driven by headline asset values or generic assumptions. They reflected how each asset was actually used within the operation, including operating intensity, duty cycles and integration with other plant. In practice, two sites with similar equipment profiles can produce materially different depreciation outcomes depending on these factors.

Mining depreciation decisions carry long-term consequences that extend well beyond annual tax outcomes. In asset-intensive operations, small errors in classification or assumptions about use and lifespan can compound over time, distorting deductions and creating compliance risk.

BMT Tax Depreciation works with mining operators, contractors and advisers to assess how equipment is physically constructed, installed and used on site, and how those realities translate into compliant depreciation treatment. This approach recognises the complexity of mining assets — including staged commissioning, rebuild cycles, relocations and integration with permanent works — rather than relying on generic asset categories or templated schedules.

To discuss a mining asset or request a tailored depreciation estimate, contact BMT Tax Depreciation on 1300 728 726 or Request a Quote.