It was believed to be the first time the nutrient had been sold to the North American market, NZ Fulvic director Rhys Brooking said.
A factory upgrade was planned to process the mineral in Kawerau for export markets.
It was hoped the factory would eventually employ 30 locals — in the town with one of the highest unemployment rates in the country — as the company sought to grow international and local distribution volumes.
Brooking believed the potential was "massive", saying there was "very large interest" in the US.
The product was also being launched in China.
The process used to extract the nutrient involved filtering the soil to separate the fulvic acid from the humus.
The land was later reinstated, in line with an organic approach to production, he said.
He was not aware of any other sites in New Zealand that were suitable for human application; a few seams from coal sites throughout the country had been tested but none were suitable.
Internationally, there was an established market for fulvic acid among consumers looking to support their dietary needs, and Brooking believed the "purity" of the New Zealand product would appeal to the wellness market.
While it had been a "difficult journey", it was very rewarding seeing what the product was doing for those who purchased it, he said.
The team stood at about 11 but it was looking to grow.
The product was processed at Kawerau, using artesian water, but there was interest in also having a South Island presence.
Such a presence would help with brand awareness and bring the brand closer to the source, and there was also potential for industrial tourism.
An organically-certified nutrient-rich fertiliser product was also being produced while certification for the fulvic acid supplement was being worked on.