It was a tragic loss for all of Sydney when South32's proposed $956 million Dendrobium extension project located on the outskirts of the city was knocked back by the New South Wales Independent Planning Commission.

When you look past the sky scrapers and bustle of the city you realise it is the state's biggest export - coal - and other forms of mining that shoulder the burden of driving the economy.

The NSW Minerals Council's latest annual member company expenditure survey found the 27 participating mining companies directly injected $14.9 billion into the NSW economy in 2019-20.

A big part of this expenditure is concentrated around coal.

NSWMC CEO Stephen Galilee said this represented an increase of $1.2 billion on the previous financial year - a very strong result given the survey period included the first half of 2020 when the impact of COVID-19 was being felt across the economy.

"These results also demonstrate the importance of mining for thousands of small and medium businesses in regional NSW and across Sydney that supply our mines," Galilee said.

"While some don't realise the strong connection Sydney has with mining, many Sydney suburbs are home to hundreds of local businesses that are part of this mining supply chain, particularly in Western Sydney."

With tourism to Sydney and its beautiful harbour flat because of the pandemic and office workers staying home, it is mining that continues to deliver.

The future of Sydney lies in real projects such as the Dendrobium extension, which could have created ongoing wealth for the city.

Instead, the city pinned its hopes on Crown's $2.4 billion hotel and casino complex that now lies in limbo because the NSW Gaming Commission found its business model of flying high rollers to gamble was not sustainable and concerns about the conduct of the company's board.

Westfield's massive shopping complex in Pitt Street Mall cost about the same as the Dendrobium extension project would have.

No-one can deny the business and economic activity that that shopping centre brings to Sydney.

However, retail is only a small part of the economic equation and it actually encourages the spending of money on mostly imported goods.

Coal from the Dendrobium extension project would have been exported or sent to Bluescope Steel at Port Kembla where it would have been value-added and made into steel.

It would have provided exports at a time when the state needs them the most.

While the IPC knocked back Dendrobium because of the threat it believed it would pose to Sydney's water supply, the government must think hard about the viability of the city's economy.