Mining Equipment Depreciation

The Units-of-Production Method in Financial Reporting

While MACRS is required for federal income tax, the units-of-production (UOP) method is the dominant depreciation approach for financial reporting under both US GAAP and IFRS in the mining industry. UOP ties cost recovery directly to the volume of material extracted, matching depreciation expense to the revenue it helps generate—a concept particularly meaningful when a haul truck operating in a high-grade ore zone produces far more economic value per hour than one working low-grade material.

Under UOP, total depreciable cost is divided by estimated total production capacity, then multiplied by actual production each period. A $2.8 million haul truck with an 80,000-hour estimated life and $200,000 salvage value has a per-hour rate of $32.50. In a 5,000-hour year, the truck generates $162,500 of depreciation expense. In a slow 2,000- hour year, only $65,000 is recorded—an automatic counter-cyclical adjustment that straight-line and declining balance methods cannot replicate.

Haul Truck Lifecycle and Major Component Accounting

Modern mining haul trucks—Caterpillar 793, Komatsu 930E, Liebherr T 284—cost between $3 million and $6 million each. These trucks are not replaced as single units. The frame, powertrain, and engine each have distinct lifecycles, and many large mining companies apply component accounting (required under IFRS, recommended under GAAP for significant assets), treating the engine, drive train, body, and tires as separate depreciable components.

A truck engine overhaul at 40,000 hours costs approximately $400,000 and restores remaining asset value—but the replaced engine must first be written off before the new engine is capitalized. Tires on large haul trucks cost $40,000 to $80,000 each and wear out every 4,000 to 6,000 hours, making them candidates for supplies expense treatment rather than capital asset tracking.

Depletion and Depreciation: Two Parallel Cost Recovery Streams

Mining operations run two simultaneous cost recovery systems. Depreciation applies to tangible equipment—drills, loaders, processing plants, and conveyors. Depletion applies to the mineral reserves themselves, recovering the capitalized cost of acquiring mineral rights and exploration expenditures. Under percentage depletion, qualifying domestic mines may deduct between 5% and 22% of gross income from mineral production annually, independent of actual cost incurred.

Both streams operate in parallel with equipment depreciation, making mining one of the most tax-complex industries in the capital asset space. Large operators with multiple mine sites, multi-currency operations, and varying ore grades often maintain separate fixed-asset subledgers for each mine and must reconcile book UOP depreciation with MACRS tax depreciation across each reporting period.