Investors were impressed, pushing Horizonte's share price up 12% in London to 2.4p (US3.1c).
As outlined in its feasibility study, Araguaia will be an openpit mine with a rotary kiln electric furnace process plant producing 14,500 tonnes per annum over 28 years at a capital cost of US$443 million.
The build time is estimated at 31 months.
Horizonte CEO Jeremy Martin said the permit meant everything was on track.
"Subject to funding, the company is now in a position to commence construction with the necessary environmental permits approved, including water abstraction permits issued in 2018 together with the newly issued [construction permit]," he said.
The permit arrived on time, with Horizonte saying last year it would come in the March quarter.