In fact, I can smell horse from where I'm standing.

It seems fitting, moments before setting out for a flight over the Hunter Valley to see for myself what coal mining has made of this patch of land which has been a battleground for many years, fought over by farmers, families, tourism and vineyard operators, conservationists, and the equine industry.

Our friendly pilot, Sam Brady, has good news - the plane is good to go. The bad news is my headset is not working, so I won't know what we're flying over. Perhaps that's just as well. Otherwise, it's a perfect day for a flight.

The early morning fog has lifted, the sun has come up, and the view over the Hunter Valley is spectacular. Rolling green hills, carefully carved-out paddocks, oases of trees, little rivers and dams.

On the way to Scone from Newcastle, there were few hints of what was to come, apart from a few (very) large road signs pointing to mines, the names of which have become familiar - Mangoola, Hunter Valley Operations, and others.

There was a glimpse of a pit between thinning screens of trees just outside of Muswellbrook, and some coal trains (of course) but not much else to give away what was about to come.

As my guide later tells me: 'It's all very well to drive around, you can't see everything from the road - everywhere you go they've always got this avenue of trees ... but back in behind that, it just goes on for miles. It's just hole after hole after hole. Unbelievable."

He's done this flight himself, about 10 years ago.

Ten minutes in, south east from Muswellbrook, the first crater comes into view.

It's Mt Owen, and the shape, scale and emptiness of that crater reminds me of something out of a Star Wars movie (the 'Great pit of Carkoon' in 'Return of the Jedi' to be precise - and yes, I had to look that up).

But much, much bigger.

It is lunar-like. Mounds of dirt and rubble piled high beside the void look like patchwork quilts from the air, and the trucks moving it from one place to another look like very small Tonka trucks.

I know that if I were to stand beside one, it's tyres would tower over me, so my mind is really struggling to wrap itself around the sheer scale of what I am seeing below.

Smoke rises from centre of a pit we are passing, as trucks make their way up along layer upon layer of roads cut into steep, terraced sides of the pits. It is sinister looking. Like a very large bomb site, only neater.

Saline lakes, and long, turquoise green patches of what looks like dried up salt (but am later told are ash dams), take over the view and again, with a brain wired for words over numbers and scale, I struggle to get a true sense of the size and magnitude of what I am seeing.

It's big. It's a lot. And those ash dams are almost glowing. Toxic.

Here comes Drayton. It looks the size of a small city - like you could pick up the township of Scone and drop it into that void and have room left over.

It goes on and on, layer upon layer upon layer, years and years and years of human ingenuity and productivity - or vandalism, depending on how you look at it. Dreadful, and yet a little bit beautiful in a pure-feats-of-engineering kind of way.

Absolutely devoid of life.

The air does not appear to be moving down there, but for the clouds of dust emanating from what seems like a scarce amount of actual activity. Lifeless.

Some of the mines appear piecemeal in comparison. Rambling, misshapen things that seem to have expanded in unexpected and unpredictable ways with no pattern or direction, other than where the black gold lies beneath.

It's hard to know precisely where the Hunter Valley started and ends, but it seems as if the mines take up less of it than I'd imagined they would.

Back on the ground, however, I gain a different perspective.

My guide, an ex-miner and Hunter Valley local, is taking me up close, personally, to the coal face - the noise, the dust, and the mining-related infrastructure.

It's intimidating.

It is clear that mining companies have done their best to make sure these sites are not only inaccessible, from a safety-perspective, but also hidden from view. You can't help but feel you're not supposed to be here, which creates a slightly sinister undertone.

The sheer volume of coal and rubble being moved by trucks, trains, loaders and drag lines, gives me a glimpse into what it might be like to live nearby.

The trucks, which from the air looked like children's toys, now appear monstrous, driving by periodically, their approach signalled by a loud, rumbling hum which you can hear coming from behind earthern walls which conceal them until they emerge through a gap near where we are standing - back and forth in army-like procession.

Driving from one site to the next, we can see the names on the fences of families which have long since abandoned the land. My guide knows when they sold out, where they've gone, and what they've lost and left behind.

That brings home an opportunity-cost that only comes from spending time with people who've borne witness to it, who live, or have lived, on coal country.

Turning onto Wybong Road, just outside Muswellbrook, there is a makeshift sign on the corner inviting 'Wybong water users' to a community meeting. One of the many groups of community members affected by what's happening on the ground and trying desperately to get a handle on it.

We stop at a little paddock which will soon become part of a planned expansion of Mangoola. Work has begun on construction of an overpass to move the coal from here to elsewhere.

There is an estimated 52 million tonnes of coal in that paddock which will extend the life of the Mangoola mine to 2030.

In all, there are 21 coal mining projects in the pipeline for the Hunter Valley - extensions, expansions or modifications, which, according to the NSW Minerals Council, will be worth over $3.6 billion in capital investment, create 7500 jobs, and a potential $2 billion plus in royalties.

Critics say existing mines operate below their stated capacity, and that the same will happen with those in the pipeline - that they will under-deliver on claimed economic benefits, and exacerbate what they describe as a "production gap" at existing mines through competition.

There are signs that where approvals have been granted, mining companies are stalling - are they doing the sums and pulling up short, guarding against the risk of stranded assets?

One of the arguments that the NSW Minerals Council puts up in favour of the continued expansion of coal mining in the Hunter is international demand for our high quality coal. If emerging markets in south eastern Asia don't source clean coal from Australia, they will source 'dirty' coal from somewhere else.

And yet change is coming. Researchers say that economic drivers will, and to some extent already are, forcing change.

Australia's four biggest banks, the Commonwealth Bank, Westpac, the ANZ and National Australia Bank, have pledged alignment with the Paris Climate Agreement and committed to stop financing thermal coal by 2030.

The Commonwealth Bank's climate commitments say its exit from the sector is "subject to Australia having a secure energy platform". Progress and activity on that front is exploding forward.

In the meantime, what is very clear is that significant public support and political will are vital to ensuring the people of the Hunter Valley and other coal mining communities are not left behind when the black rivers of gold stop running.

And, as young people living on coal country are acutely aware, community buy-in is essential to ensure a successful transition. Sooner, rather than later.

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