Highlights

  • All-in sustaining cost, or AISC, measures the cost of maintaining current gold production on a per-ounce basis, going beyond simple cash costs.
  • The metric was defined by the World Gold Council with member companies and is now widely reported by gold producers.
  • AISC is a non-GAAP measure, so differences in cost allocation, by-product credits and accounting choices can affect comparisons between producers.

Gold producers on the ASX regularly report their results using a measure called all-in sustaining cost, often shortened to AISC. For anyone following Gold Stocks, understanding this figure is central to reading quarterly reports, comparing producers and assessing how resilient margins might be if the gold price changes. With bullion prices at elevated levels and many Australian producers reporting strong cash generation, cost discipline has become a key talking point in the sector. This explainer outlines what AISC includes, what it leaves out, how it differs from earlier cost measures and why shareholders should read it alongside other financial information rather than in isolation.

What All-In Sustaining Cost Measures

AISC captures the total cost of sustaining a gold mine's current level of production, expressed per ounce of gold delivered to market. It combines the direct costs of Mining and processing with the additional spending required to keep an operation running at its existing output, such as replacing equipment and maintaining infrastructure.

Because it is expressed per ounce, AISC allows the cost of producing gold to be compared directly with the gold price. The gap between these figures gives a broad indication of the Margin a producer earns before growth spending, interest and tax.

How the Metric Came About

Before AISC was introduced, the industry largely relied on cash cost per ounce. That measure covered direct operating expenses but excluded the Capital needed to maintain output, which could understate the true cost of production, particularly at mature mines with heavy sustaining capital requirements.

The World Gold Council worked with its member companies to define AISC and an associated all-in cost measure, aiming to improve transparency and consistency in how producers report costs. The metric has since become the standard reference point across the global gold industry, including among Australian producers.

The Key Components of AISC

Cash operating costs form the foundation and include mining labour, fuel, explosives, processing reagents, maintenance and site administration, along with royalties and production taxes. Sustaining Capital Expenditure is then added to cover equipment replacement, infrastructure upkeep and works such as tailings storage improvements.

AISC also includes an allocation of corporate general and administrative costs, sustaining exploration such as near-mine and infill drilling that extends mine life, and provisions for reclamation and closure spread across the operation's life. The total is divided by ounces shipped and recognised in the period, and the figure is commonly reported in US dollars globally, while many ASX producers report in Australian dollars.

What AISC Leaves Out

AISC excludes growth capital for new mines or major expansions, greenfield exploration, and costs associated with developing new operations. It also excludes Debt servicing, interest and income tax, which means it does not represent the full cash outflow of a business.

The broader all-in cost measure adds growth and expansion spending back in. It is less widely reported but offers a more complete view of total spending, especially for companies in the middle of large development programmes.

Limitations When Comparing Producers

Because AISC is a non-GAAP measure, companies have some discretion over how they classify costs. Larger diversified producers can spread head office costs across more ounces, which may make them appear cheaper per ounce than single-mine operators. By-product credits from silver or copper can reduce reported AISC significantly, so a low figure may reflect by-product Revenue rather than operational efficiency.

Stockpile accounting can defer costs to later periods, and some companies classify community contributions as sustaining costs. A low AISC can also coexist with heavy growth spending, so the figure should be read with the cash flow statement. Tracking the same company's AISC over time is generally more informative than comparing single periods across producers.

Cost Pressures Across the Gold Sector

Industry costs have risen in recent years, reflecting labour inflation, diesel prices and royalties that increase alongside higher gold prices. For Australian producers, a tight labour market in mining regions and energy costs have been notable contributors. Watching how each producer manages these pressures, and how it explains movements in its reported AISC from quarter to quarter, can help shareholders separate temporary effects from lasting changes in an operation's cost base.

A Useful Metric Best Read in Context

All-in sustaining cost gives shareholders a clearer view of what it costs to maintain gold production than older cash cost measures, and it has become the standard benchmark across the industry. However, its exclusions and the discretion involved in calculating it mean it works best alongside cash flow statements, growth spending disclosures and trends over time. For those following ASX gold producers, understanding AISC is an essential part of interpreting quarterly reports and sector comparisons.