A Due Diligence Framework for Mining Companies Planning Solar Integration

Thinking about bolting a solar array onto a working mine site?

Good thinking on your part there. Diesel fuel is costly, grid electricity in remote areas is unreliable, and each year boards demand tougher emissions questions.

But here’s the problem:

Very few solar projects fail at mine sites due to panels not performing. They fail when someone doesn’t verify the electrical backbone can handle what is being bolted to it.

Solar is the easy part.

Integration is when budgets go flying out the window, schedules get pushed back by a year or more, and someone explains to the board why something REALLY expensive was late.

This is the due diligence to occur prior to ordering 1 module.

What you’ll walk away with:

Why Switchgear Quietly Controls The Timeline
The 5-Step Due Diligence Framework
The Mistakes That Sink Mine Solar Projects

Why Switchgear Quietly Controls The Timeline

Mine sites have large appetites for power. Simply crushing and grinding takes a significant share of total site power draw, while estimates from across the industry indicate mining energy requirements could rise 36% by 2035 as ore grades decline and tonnage rises.

So the case for on-site generation writes itself.

The tricky bit is the interface. Solar needs stepping up, protecting, synchronising and distributing… and each of those tasks flows through switchgear.

The modular switchgear lineup is what connects a new array, the battery storage and existing distribution grid into a cohesive system. Get your lineup right and solar plugs in seamlessly. Get it wrong and you find your substation being redesigned mid commissioning. On dusty, corrosive, space-constrained mine sites consider quoting a medium voltage GIS solution upfront, because sealed technology will condense that modular switchgear lineup into a fraction of the footprint required for an air-insulated equivalent.

That one decision affects:

How much substation land has to be cleared
How long procurement actually takes
How much maintenance access is required
Whether phase two is a bolt-on or a rebuild

Exactly why it needs to be part of due diligence… not detailed design six months later.

Step 1: Audit The Existing Electrical Backbone

Before anyone models any kWh, someone needs to walk the site with single-line diagrams.

The question is simple: does reality match the drawings?

Rarely on legacy mines. Panels are exchanged out, feeders get added, and documentation slowly becomes obsolete over two decades of production.

The audit should confirm:

Actual bus ratings and spare cubicle capacity
Age and condition of the protection relays
Fault levels at every possible connection point
Earthing and arc flash study status

Solar and storage additions can take fault levels that are near equipment ratings and push them over. That is a problem you want to identify on paper, not when energising.

Step 2: Model The Load Profile Before Sizing Anything

Here is where plenty of projects go sideways.

Mine loads are irregular. Startup of a mill, hoist loading and ventilation fan acceleration causes demand spikes solar will never be able to follow.

Therefore the array should never be sized against average production. You size against the actual load curve — hourly, seasonally.

It’s helpful to look at comparison with the DeGrussa copper-gold mine in Western Australia. Its combined solar/battery hybrid plant consisted of 10.6 MW solar and 6 MW battery storage, yet only covered 20% of annual power at its peak period.

That isn’t a failure. That’s realistic.

Solar plus storage paired with a mine is a fuel savings tool, not firm generation replacement. If anyone tries to tell you otherwise they are selling something.

Step 3: Stress-Test The Interconnection Point

Now for the technical heart of the exercise.

Protection Coordination

Introducing generation reverses the fault current flow. Existing protection settings were calculated for power flowing in one direction – from the grid/diesel plant out through the loads.

Solar can flip that back. Relay settings, directional devices and islanding preventions all have to be verified again.

Voltage Regulation

Clouds can reduce array output dramatically in seconds. On a weak system that may appear as voltage sag on the mill.

The interconnection study should model worst-case ramp events, not sunny-day averages.

Room To Grow

Mine substations are seldom designed with excess capacity. Ask if the selected modular switchgear family will allow additional bays to be added later without a station outage, phase two of everything always follows.

Step 4: Get Honest About Lead Times

Equipment lead times have become the quiet killer of renewable projects.

Panels and inverters are commodity products. Medium voltage equipment is not. Transformers and switchgear have lead times measured in quarters, not weeks.

Due diligence should capture:

Quoted delivery windows, in writing
Availability of critical spares
Local service support within reach of site
Factory acceptance testing arrangements

If a mine loses a main distribution board and sits for months waiting for a replacement, they are no longer operating a solar project. They are operating a crisis.

Step 5: Score The Supplier, Not Just The Price

The cheapest quote is almost never the cheapest system.

Rio Tinto’s investment of approximately $600 million into solar and storage capacity in the Pilbara is a good example of how large the big players are sizing up these projects at, and projects of this scale operate or don’t based on supplier discipline, not unit costs.

Score every supplier on:

Track record on mining and heavy industrial sites
Standards compliance and full test documentation
Ability to support a future expansion
Delivery commitments that hold up under questioning

Now factor in reliability. Mine downtime costs significantly more than the difference between two switchgear quotes ever will.

The Mistakes That Sink These Projects

Most failures repeat the same short list of errors.

Watch for these:

Sizing the array before studying the load curve
Treating battery storage as an afterthought
Skipping the protection coordination study
Ordering panels before ordering switchgear
Assuming the substation has room to spare

Notice how many of those are electrical problems rather than solar problems.

Studies of renewables at mine sites have shown that energy costs can be reduced significantly through on-site generation, especially when compared to brownfield sites. However, this savings potential can only be realised if the integration process is executed well. The profit is in the engineering, not the sales.

Putting The Framework To Work

Installing solar at mine sites makes a lot of sense but has a bad reputation. That reputation is deserved, but only because of poor integration planning.

A quick recap of the framework:

Audit the existing electrical backbone against reality
Model the real load profile before sizing anything
Stress-test protection, voltage and expansion room
Lock down lead times and spares in writing
Score suppliers on reliability, not headline price

Do all five and it becomes mundane. Mundane is what you want a mine’s power system to be.

Skip them and the array stands in a laydown yard whilst engineers debate fault levels and opportunities quietly evaporate.