Uranium miner Extract Resources Ltd (ASX: EXT) revealed on Wednesday a tenfold resource upgrade on its Rossing South project in Africa, elevating the site project as the world's fifth biggest established reservoir of uranium so far.

The company's Namibia exploration site is now believed to hold indicated and inferred deposits of up to 367.1 million pounds of U3O8 as Extract added that work so far done on the site also pointed to resources increase of 480 million tonnes of U3O8, which is a key component of yellowcake.

Extract managing director Jonathan Leslie said that the resources upgrade "is a tenfold increase in indicated resource from our previous resource statement in July 2009."

In its statement to the securities exchange, the company said that the resource jump in Rossing South easily pushed its standing to number five in the world's largest uranium deposit, adding that the ongoing project boasts of "the largest in-situ and highest grade, granite-hosted uranium deposit in Namibia."

Extract Resources expressed confidence that the spiked up deposits would buttressed the company's future endeavour "which is the completion of the definitive feasibility study and takes it in another step forward from a successful explorer to becoming a major uranium producer."

Also, Mr Leslie said that further upgrades from the location's resources could be expected as he stressed that "we have mineralisation still open in zones one and two and a large area that still remains to be explored."

As of 1230 AEST on Wednesday, Extract Resources shares were trading at $6.87, following its gain of 15 cents or 2.23 percent from previous trading day.