Fonterra will not confirm its total coal use for commercial sensitivity reasons and Ministry of Business and Innovation figures provide only annual sector usage rather than that of individual companies.
Solid Energy's 2014 annual report said the Huntly power station and NZ Steel remained its two biggest customers and that it had signed a contract for 100,000 tonnes with an unnamed customer.
Fitzsimons said the only possible user for that amount of coal would be Fonterra.
In February, Fonterra subsidiary Glencoal denied Cana's claims it had put its plan for the opencast mine on hold indefinitely after public opposition and falling coal prices. Glencoal said at the time there had been some delays because of the need to minimise environmental impacts.
Consent to mine about 700,000 tonnes of coal a year from the proposed Mangatangi mine was given in late 2013, subject to conditions addressing environmental and health concerns.
The planned mine was allowed to extract coal over eight years and the land had to be returned to pastoral farming once mining ended.
"While local residents are celebrating the reprieve for their community, none of this reduces the coal that will be burned, nor the carbon dioxide used," Fitzsimons said.
Fonterra said it was "committed to optimising its energy mix towards cleaner, more efficient forms of energy, and continues to investigate secure, cost-effective alternatives to reduce emissions intensity and contribute to our energy efficiency".