True that Buller is high quality bituminous coal ideal for coking coal. Not used to 'steaming' coal terminology but ill swap that out for one I am used to which is thermal coal.
Maramarua (204,790 tonnes in 2022) and Rotowaro (406,848 tonnes in 2022) in the Waikato still produce plenty of thermal coal. Mainly for Fonterra for milk processing and Glenbrook for steel. Wouldn't be that hard to get enough production for Huntly but unfortunately the cheapest Indonesian thermal coal is high ash and high sulphur, China banned it about 10 years ago making it the cheapest thermal coal in the market. No standards here so GNE chooses to screw local workers and the environment both in Indo and here to save a few bucks.
https://www.theguardian.com/world/20...ng-almost-15bn
Your correct we don't have a deposit like Powder river basin but plenty of mapped thermal coal resources in the Waikato we could use to save some Indonesian rainforest, help our balance of trade and make a few local jobs. Better if Labour hadn't gutted the gas industry, then this wouldn't be the crappy trade off we are left with.