What Does Good Availability Actually Look Like?

As I Experienced It

I cut my teeth in maintenance on electric draglines, shovels, and drills.

These machines were the primary production assets and the expectation was always clear:

• Around 90% availability or above
• Maybe dropping to 88% during major shutdown years

That was simply considered normal. Later, when I moved into mobile equipment maintenance, I carried the same thinking with me. I assumed 90% is the minimum standard and for the fleets we managed, that’s where we kept them. However, as I started working across more operations, I noticed something that some sites were targeting 85% availability on mobile equipment fleets and often struggling to achieve that and they considered it acceptable performance.

That got me thinking:

What actually defines good availability performance?

Because clearly, the answer isn’t the same for every operation.

Common Practice

A lot of operations set availability targets based on:

• Historical performance
• Budget pressure
• What the site has “always achieved”
• Or what feels realistic given current problems

The danger is that low expectations slowly become normalised and once that happens:

• Reactive maintenance becomes accepted
• High breakdown rates become “part of the operation”
• Poor conditions stop standing out
• Reliability drift becomes invisible

Eventually the target stops driving improvement and simply becomes a reflection of current performance.

What Actually Works

Good availability targets should reflect:

• The type of equipment
• The operating context and environment
• The wear profile of the assets
• And what is genuinely achievable with disciplined maintenance execution

In my experience, good calendar availability targets are roughly:

• 90%+ for mobile mining equipment
• 92%+ for fixed plant processing assets
• 95%+ for plants with lower wear and less harsh operating conditions such as power or hydrocarbon plants

Importantly, these numbers should always be calendar availability. Not “mechanical” availability or another manipulation excluding inconvenient downtime. Calendar availability keeps everyone honest because it reflects the true ability of the operation to keep equipment available for production, and that is what matters for the business bottom line.

The Basic Principle

Availability targets shape behaviour.

If the target is too low:

• Reliability drift becomes accepted
• Standards slowly fall
• And breakdown culture becomes normalised

Strong operations expect high availability because they know it is achievable by just getting the basics right and it drives business outcomes.

They also know that higher availability is not achieved by reducing the scheduled downtime. We will discuss next week about a structured process to achieve good performance availability but for this week reflect on your targets and outcomes. Maybe even challenge your thoughts on what is possible.

Action to Implement This Week

Review the availability targets used in your operation and ask:

• Are these targets based on what is truly achievable?
• Or are they based on historical underperformance?

Then compare your targets against:

• Similar operations in a similar operating context
• Find who is the best performer

Most importantly, make sure your operation is measuring calendar availability and that you are not mentally making excuses for under performance by blaming the equipment, operations, supply or the OEM.