(Bloomberg) – Australia’s Invictus Energy Ltd. discovered natural gas in northern Zimbabwe, almost three decades after Exxon Mobil Corp. mothballed its quest to find crude in the region.

Four samples from the Mukuyu-2 well at the Cabora Bassa project showed the presence of natural gas, the company said in a statement. While that’s a boon to the southern African country, Invictus has to drill more wells to assess volumes, and it will take years of further investment before any production can start.

“The discovery represents one of the most significant developments in the onshore Southern Africa oil and gas industry for decades,” Managing Director Scott Macmillan said in a company statement.

“The Mukuyu-2 discovery, 7 km away and 450 m updip of the Mukuyu-1 well, which can subsequently be classified as a discovery, provides confirmation of the large potential of the Mukuyu field which has a structural closure of over 200km2,” he continued.

The discovery “provides confirmation of the large potential of the Mukuyu field,” Macmillan stated. “With additional hydrocarbon-bearing reservoirs ahead, the focus now is to complete the drilling and evaluation program.”

Invictus shares jumped 28%, the most in a year.

Exxon, then Mobil Oil Corp., abandoned exploration in Zimbabwe back in the 1990s after concluding that any discoveries were more likely to hold gas than oil. Its data was used by Invictus, which in March last year reached an agreement with Zimbabwe to increase its exploration license area sevenfold.

(World Oil added additional Invictus commentary in the 3rd and 4th paragraphs).