Robust unveils bonanza silver grades from Batu Perak basin drilling

By Ruli Setiawan

ASX-listed Robust Resources Limited unveiled on Wednesday the assay results from five diamond drill holes from the latest drilling of the Perak Basin VMS target, Romang Island project, in Maluku Province, Indonesia, saying each hole intersected precious metals and base metals.

Standout results have come from the drilling on the open western side of the Perak Basin, the company said in a statement. Two holes, LWD 385 and LWD 390, were drilled in this area and both intersected strong VMS exhalative mineralization, rich in silver and other metals:

Results from LWD 385 include high-value VMS exhalative style mineralization:
o 7.4m at 4.58g/t AuEq1 and 2.99% combined base metals from 12.6m
(1.97g/t Au, 138g/t Ag, 0.08% Cu, 2.90% Pb, 0.02% Zn)

Located 80 meters south-east of LWD 385, LWD 390 intersected higher grades:
o 7.2m at 14.1g/t AuEq and 5.56% combined base metals from 18.8m
(0.77g/t Au, 707g/t Ag, 0.14% Cu, 3.11% Pb, 2.41% Zn) and including high-grade zone
o 2m at 34.84g/t AuEq and 14.00% combined base metals from 23m
(0.41g/t Au, 1,825g/t Ag, 0.33% Cu, 7.55% Pb, 6.12% Zn)

These drill results, combined with previous results and geological logging of holes where assay results are awaited, indicate the western flank of the Perak Basin remains open for further discovery. Mineralization in the basin appears to strengthen towards the west under limestone cover. This is in keeping with the company?s mineralization model of basin-bounding faults acting as feeder zones for mineralization.

High-grade manganese mineralization in Perak Basin has also been discovered in this recent round of drilling.

These results indicated that the Perak Basin, especially at the limestone covered margins, is very prospective for high-grade manganese.

Although the Perak Basin target remains open in all directions, recent drilling, utilizing five company-owned diamond drill rigs, has mostly focused on in-fill pattern drilling for resource estimation purposes. Drilling and data compilation remains on track for completion of a new Romang Island mineral resource estimate by first quarter or 2014. Additional drilling to extend this resource will be the focus of the 2014 drilling campaign.

Exploration target
On 25 September, 2014, the company provided information regarding the exploration potential of the Perak Basin2: The statement read:

An exploration target can be approximated at between 8 ? 12 million tons of between 5 percent and 7 percent combined base metals (Pb+Zn+Cu), between 1 and 2 g/t gold and between 60 and 80 g/t silver: approximately 400 to 600 thousand ounces of gold, 20 to 30 million ounces of silver, and 1 to 1.5 billion pounds of base metals. This potential quantity is conceptual in nature and only limited drilling has yet been done. There has been insufficient exploration to estimate a mineral resource and there remains uncertainty that further exploration will result in the estimation of a mineral resource.

This exploration target remains valid and is strongly supported by recent drilling.

Robust is currently drilling targets within the Lakuwahi Caldera with five rigs, all of which are dedicated to drilling the Batu Perak VMS exploration target. It is estimated that a preliminary mineral resource estimate for Batu Perak will be announced within four months but full assessment of the target may take more time, depending on the number and extent of new discoveries.

The above exploration target does not include stringer sulphide or stockwork breccia mineralization that nearly always occurs beneath the main exhalative horizon. It is likely that significant parts of this stringer zone can be mined economically, especially along the western flanks of the PerakBasin where the zone is well developed.

Editing by Reiner Simanjuntak