Nusantara Resources (ASX:NUS) has boosted the reserve at its Awak Mas mine in Indonesia by 34 per cent to 1.5 million ounces.

The much bigger reserve adds five years to the now-16 year mine life.

Investors welcomed the news, pushing the share price up as much as 15 per cent to an intra-day high of 38c this morning.


The total reserve now stands at 35.6 million tonnes at 1.33 grams per tonne (g/t) gold for 1.53 million ounces, all of which is in the “probable” category.

A proven reserve is an estimated quantity of a mineral or oil or gas that is able to be economically recovered with high certainty, while probable reserves are a bet each way at about 50 per cent certainty.

The average grade produced in the first four years is expected to be higher at 1.71g/t to deliver 127,700oz each year.

Meanwhile, mine scheduling has bumped up the mining inventory to 38.7 million tonnes at 1.32g/t for 1.68 million ounces of contained gold.

That includes 2.9 million tonnes of inferred mineral resource recovered from within the open pit designs.

Mineral resources are categorised in order of increasing geological confidence from inferred, to indicated, to measured.

Nusantara said the updated reserve established a “significantly longer mine life and presents increased optionality for future operations”.

The operation will initially process 2.5 million tonnes per annum, but Nusantara is investigating low-cost options for a “future proof” expansion to 3.9 million tonnes per annum.

Updated economics are due out this month, Nusantara says.


In other ASX gold news today:

Pantoro (ASX:PNR) has hit more high-grade gold in recent drilling at the OK underground mine at the Norseman project in Western Australia. New results include 6.05m at 22.90g/t and 1.56m at 59.62g/t.

“These additional results from the OK underground mine demonstrate the consistent high-grade nature of the deposit beneath the historic workings,” managing director Paul Cmrlec said. “The decline at OK has been fully rehabilitated and recommencement of production activities will be relatively straightforward.”

Shares edged up over 5 per cent.

Aruma Resources (ASX:AAJ), meanwhile, jumped over 33 per cent after revealing it had applied for four new exploration licences over underexplored gold prospective ground in WA and a new licence adjacent to the recently secured Capital gold project in NSW.

Los Cerros (ASX:LCL) has pinpointed new high-grade gold targets outside of the current resource at the Miraflores deposit, part of the Quinchia project in Colombia. Miraflores has an existing resource of 877,000oz at 2.8g/t and reserve of 457,000oz at 3.29g/t. The new targets will be tested in the upcoming drill program.