Robust: Mineral resource confirms Lakuwahi as world class deposit

By Romel S. Gurky

ASX-listed Robust Resources Limited reported Thursday an updated estimate of the polymetallic gold-silver-lead-zinc-copper mineral resources hosted within the Lakuwahi Project area on Romang Island.

The resources are reported on a 100 percent project basis and Robust?s interest is 60 percent.

?The new estimate is a substantial increase over the maiden estimate, reflecting consistently positive results from intensive drilling programs over the past 2? years and inclusion of important new discoveries such as the Perak Basin VMS, high-grade base metals at Batu Mas Deeps and significant silver in the Batu Putih deposits,? Robust said in a statement.

?Lakuwahi is confirming its early promise as an important and world-class deposit of precious and base metals,? it added.

The statement of mineral resources is shown in the table below, lifted directly from the independent consultant?s report.

Lakuwahi Polymetallic Resource above 0.4 g/t Au eq *? cut off

Resource?		Grade					Metal
> 0.4 g/t Au eq	Tonnes	Au g/t	Ag g/t	Cu %	Pb %	Zn %	Au Oz	Ag Moz	Cu Mlb	Pb Mlb	Zn Mlb
Inferred	43,959,000	0.34	28.6	0.08	0.64	0.72	479,000	40.4	73	621	700
Indicated	37,758,000	0.46	22.7	0.07	0.50	0.46	563,000	27.5	56	419	386
Total	81,717,000	0.40	25.8	0.07	0.58	0.60	1,042,000	67.9	128	1,040	1,086

This new global resource estimate represents a significant increase from the 2012 estimate:
? Total Resource Tons: up 80%
? Total Gold Metal: up 81%
? Total Silver Metal: up 152%
? Total Lead Metal: up 49%
? Total Zinc Metal: up 60%
? Total Copper Metal: up 35%

The Lakuwahi Deposit consists of at least four separate deposits within close proximity. Mineralization in all four areas outcrops at surface and in the case of Batu Perak becomes covered and well preserved from erosion, by a shallow sequence of soft, unconsolidated sediments in the Perak Basin. Perak Basin has been the main focus of exploration drilling for the past nine months and has resulted in some spectacular polymetallic intersections.

Classification of the mineral resources is based on several interrelated factors including the spacing of the drilling, confidence in the geological interpretation and statistical correlations.. The Company believes that further drilling will result in a significant proportion of Inferred resources being converted to Indicated or Measured category, although there is no guarantee of this.

The mineral resource estimate is sensitive to cut-off grade. In the estimate individual metals have been modelled and reported separately. Gold equivalent (Au eq) has only been used to define cut offs for reporting purposes.

The exploration story of Lakuwahi is still ongoing and very exciting - most of the deposits remain open for further discovery and there are new, untested targets that have become evident, along with better understanding of geological controls for mineralisation. The mineralisation comprising this resource estimate is contained within a large structure known as the Lakuwahi Caldera; a geological and geophysical anomaly approximately 6Km x 4Km in dimension.

Drilling to date has focused on a target known as the Inner Caldera, approximately 2Km in diameter, the outer rim of which includes outcropping breccia-hosted polymetallic mineralization. The rim of the inner caldera is partially obscured by syn- to post- mineral limestone and it is these areas which are poorly tested by drilling considered highly prospective for further discovery (for both polymetallic and high-grade manganese mineralization).

Much of the inner caldera and nearly all of the larger 6Km x 4Km Lakuwahi Caldera has yet to be drill tested. One of the revelations of the recent 12 months of drilling and one of the most significant advancements in the history of the Lakuwahi exploration program has been the discovery of the Perak Basin VMS deposit. This discovery has opened up the potential of the basins within the Lakuwahi Caldera.

For example, the Hitam Basin is now considered highly prospective for strata bound exhalative VMS deposits. The Mas West Basin, to the west and south of the Batu Mas deposit is another target highly prospective for VMS mineralization. There is ample evidence from the drilling at Batu Mas that strata-bound and breccia-hosted, barite-rich gold-silver-base metal extends to the south and west of the current defined mineral resource.

Another significant recent discovery has been the Batu Mas Deeps high-grade base metals which seem to be well correlated with large, deep-trending, geophysical resistivity anomalies. The high grades intersected at Batu Mas Deeps could potentially support underground mining. More drilling is needed to test for extensions and continuity of these high-grade zones at Batu Mas Deeps and to follow up other deeper, high-grade intersections such as those discovered as part of the Perak Basin western barite feeder system.

Definition of the polymetallic mineral resource has now advanced to a stage where the Company will commence preliminary mine and process flowsheet design, aimed at unlocking the considerable value inherent in the Lakuwahi Deposit. Given the multi?metal nature of the ore (presenting both opportunities and challenges), processing is seen to be the key.

An initial metallurgical test programme has been designed by our experienced consulting team, SDF Pty Ltd of Perth which has a longstanding professional relationship with the Company. Large diameter drilling to obtain material for this work is scheduled to commence later this quarter.

Preliminary metallurgical tests have shown promising flotation results and heavy-media (gravity) beneficiation of the sulphide mineralisation. The coming testwork will further investigate these opportunities as well as examine variability of material types across the deposits.

As well as gold, silver, lead, zinc and copper, the Lakuwahi deposits contain large quantities of barite. Although the current resource has not been optimised for this valuable industrial mineral, MA is currently working on an estimate for barite, contained within the boundaries of the polymetallic resource, which will be announced under separate cover once available. A high purity barite by-product, could possibly be created during processing of the polymetallic ore. This may have a significant impact on the economics of the Project.

Editing by Reiner Simanjuntak