The Canadian company had flagged a firm indication of government support in April.
Yesterday, it said it had entered definitive agreements to finalise commercial terms to progress Madaouela.
Under the key terms, the state would receive a 10% free-carried interest, plus a working 10% interest in exchange for a US$14.5 million debt settlement over the final permit acquisition payment and challenged area taxes.
GoviEx's mining permit would be expanded to include the 5.96 million pound Miriam deposit and the state had confirmed Madaouela's environmental and social impact assessment certificate also covered Miriam, GoviEx said.
The junior would also be issued new, nine-year exploration permits and its payments for the Madaouela I mining permit would be deferred for three years or until financing, if earlier.
CEO Daniel Major said the agreements were a key step and continued to illustrate the "constructive environment" it had experienced operating in Niger since 2007.
GoviEx envisages initial capex of US$359 million for Madaouela for a 21-year mine with steady-state production of 2.69Mlb U3O8, citing a breakeven price on an NPV (8%) of $48/lb.
The uranium spot price had hit a three-year high of $28.90/lb in January but has softened to below $25/lb.
Major said feasibility study work was continuing and focused on improving project economics.
"We believe the outlook for the uranium market is positive," he said.
A company presentation last month pointed to the nuclear reactor build rate being at a 25-year high in 2018 and forecast increased demand.
The company had raised $3.5 million (US$2.7 million) in an increased private placement at 17c per unit in April.
It had been hoping to receive a similar amount in loan repayments by June 30 but said last week it had entered a forbearance agreement with Linkwood Holdings and Medea Capital Partners as guarantor, to allow Linkwood time to liquidate assets and repay the loan in full plus interest over the coming year.
GoviEx counts Denison Mines, Ivanhoe Industries and Cameco among its major shareholders.
Its shares have ranged from C12-25c over the past year and closed unchanged on Friday at 16c, capitalising it at $67.7 million (US$51.8 million).