The revival of the coal industry has spurred fresh debate on its economic viability and new criticism on environmental grounds.
Among other things, collapsing coal prices brought about the death of Solid Energy and an end to over 70 years of state mining in this country.
But it produced the birth of BT Mining, 65 percent owned by Australian listed Bathurst Resources and 35 percent owned by the Nelson firm, Talleys.
This new organisation is busy digging out coal from Solid Energy's old mines.
In addition, another mining firm, Stevenson, wants to develop a new coal mine 12 kilometres up the Buller River from Westport.
Coal prices have inched up from their nadir of early 2016, but are still well below their peak five years ago.
But Cindy Baxter of Coal Action Network Aotearoa warned that the price was still unreliable and that the industry was still economically unsound.
In addition, the coal should be left in the ground for environmental reasons, she said.
"We have to end our use of fossil fuels by 2050 if we want to stop global warming."
But Chris Baker of the mining organisation, Straterra, said there was a problem with leaving coal in the ground.
"A lot of the coal that Solid Energy mined and that other companies have come in and bought, is produced to make steel," Mr Baker said.
"We don't have a plan to make steel with any other means than coking coal."
Cindy Baxter said non-coal technologies were being developed, and proper recycling of existing steel would greatly reduce the need to dig out new coal.
Economics journalist Brian Fallow has no love for the coal industry but cautioned against hasty action.
He was economics editor for the New Zealand Herald for many years and said New Zealand has to be very careful about killing off any branch of its economy.
"I think we need to acknowledge the melancholy fact that New Zealand struggles to earn a living as a trading nation," he said.
"We are enjoying the most favourable terms of trade for 40 odd years and still we are running a trading deficit of $3 billion and a broader current account deficit of $7.5 billion that we have to fund by borrowing or selling off assets."
Brian Fallow said the cumulative effect of doing this year after year really costed New Zealand.
"If there are resources like coal or other minerals, natural resources of that kind, that we can export or substitute for other imports like oil, we have to think carefully about doing that," he said.
"(We should) not adopt some sort of national Nimby idea of leaving our stuff in the ground and let other countries incur the environmental costs of providing the wherewithall of the civilisation on which we depend."
The argument over coal is just one of many. There is also dispute over undersea mining.
An ironsands project off the coast of Taranaki is headed for the courts and a phosphate project off the east coast of the South Island will be re-submitted to the Environmental Protection Authority next year.
In addition, a planned revival of a discused gold mine in the Bay of Plenty's Karangahake Gorge has spurred protests.
Outspoken is a series in which RNZ's experienced correspondents host debates on some of the top issues of the year - and the year ahead. Listen to episodes here.