Indonesia focussed gold developer, Nusantara Resources, has increased its confidence in the potential for a grade uplift to be realised once its Awak Mas gold project on the island of Sulawesi, Indonesia, is in production.
This follows the receipt of very positive results from an exploration benching program carried out to map and sample the exposed high-grade vertical vein structures within the Rante starter pit.
A 100m exploration bench cut into the pit area and exposed a considerable, continuous width of gold mineralisation.
Two trenches, one in the face of the bench and one in the floor of the bench, were excavated and exposed multiple sub-vertical structures.
Sampling of the trenches outlined additional high-grade gold structures that were not captured by the previous ore reserve drilling and related block models.
In addition, assays of the samples returned produced results of 66m grading 1.56 grams per tonne gold from the face and 62m @ 2.3g/t gold from the floor.
Analysis is being carried out on the impact of the additional gold structures identified and the resultant assays against the existing reserve drilling and 3D block modelling.
Management said that while the results were encouraging, the cost of closer spaced deposit drilling is not considered to be cost-effective and operational grade control drilling will be used to manage ore processing in future operations.
Nusantara is looking into carrying out further close-spaced drilling to further prove up its potential upgrading concept.
The company is also carrying out a ground-based geophysics program over a 3km strike length covering the Salu Bulo deposit and potential strike extension of mineralised structures to the north and south.
Previous exploration survey work had identified the potential for Salu Bulo, which has elevated gold grades compared to other areas of the project, to host extensions to known mineralisation.
Mineralisation trends also extend into large, untested areas.
Salu Bulo has an ore reserve of 2.8 million tonnes @ 1.67g/t gold containing 150,000 ounces of gold within a mineral resource of 3.6 million tonnes @ 1.6g/t gold.
Geophysical work has delineated consistent signatures along the structure from Salu Bulo, identifying targets that will be followed up with diamond drilling, which is currently being programmed.
Executive Chairman Greg Foulis said: “Nusantara is very focussed on moving the Awak Mas Gold project through financing and into development, notwithstanding, we haven’t taken our eyes off exploration.”
“We anticipate a very exciting second half 2019 defining and drilling new targets in what is proving to be a very large gold mineralisation system”
In the Awak Mas definitive feasibility study released last year, Nusantara estimated that upfront capital costs to develop the project were USD$146m.
The study also outlined that an open pit mining operation could produce about 100,000 gold ounces per annum and generate an impressive after-tax cash flow of about AUD$55m, or about AUD$1m a week, with payback in 4 years.
Awak Mas currently has an impressive ore reserve of 1.14 million ounces grading 1.32g/t gold.
By Matt Birney
