The Batu Mas Prospect, which means 'Gold Rock' in Bahasa Indonesia, is one prospect area within the larger Lakuwahi Project, and is considered to be one of Robust's key targets for mineralisation on Romang Island.

Exploration activities such as surface mapping, geophysical surveys, soil geochemistry and drilling data have led to the recognition of distinctive flat-lying lithological controls on the formation of the hydrothermal breccia-hosted mineralisation at the Batu Mas Prospect. These controls to mineralisation mean that the mineral deposit discovered so far at Batu Mas generally consist of an upper oxide, gold and silver rich cap, which is underlain by polymetallic-bearing breccias containing potentially economic concentrations of gold, silver, copper, lead and zinc.

Diamond core drilling information has been vital to the preparation of the geological and mineralisation model for the Batu Mas Prospect. These models underpinned the maiden JORC code compliant resource estimate at the Lakuwahi Project released in January 2012.

Currently the Batu Mas Prospect has a strike length over 350m and is considered to be open for mineralisation in all directions.

Some diamond drill mineralisation highlights from the Batu Mas Prospect are holes such as LWD166, which was drilled to test the north-eastern extensions of the Batu Mas prospects mineralisation. This hole intersected the thickest continuous zone of mineralisation so far encountered on Romang Island. The hole terminated in mineralisation. The upper section of LWD166 is rich in silver and gold and results include:

• 106.3m @ 1.01g/t Au Equivalent ¹ (0.36 g/t Au, 31 g/t Ag) from 8m

Underlying, and partially overlapping this upper section, is a well mineralised and thick base metal-rich breccia body which includes higher-grade zones as follows:

• 136m @1.36% Cu Equivalent ² (0.22 g/t Au, 21 g/t Ag, 0.17% cu, 1.23% Pb, 1.88% Zn from 59m:
  • Including 50m @ 2.14% Cu Equivalent (0.23 g/t Au, 35 g/t Ag, 0.27% Cu, 1.77% Pb, 3.29% Zn) from 73m
  • And 10m @ 3.60% Cu Equivalent (0.27 g/t Au, 63 g/t Ag, 0.56% Cu, 3.10% Pb, 5.13% Zn) also from 73m

These exceptional results confirmed to Robust that Batu Mas is open to the east and at depth and represents a new direction for further exploration.

Another hole of note was LWD120 which was drilled on the south-eastern extremity of the Batu Mas prospect and intersected high-grade massive to semi-massive sulphide mineralisation over a wide zone. Results include:

• 22m @ 7.74% Cu Equivalent (1.36% Cu, 10.03% Pb, 10.24% Zn, 0.14 g/t Au, 57 g/t Ag) from 126m
  • Including 10m @ 10.25% Cu Equivalent (2.36% Cu, 8.65% Pb, 16.76% Zn, 0.16 g/t Au, 61 g/t Ag) from 134m

This is a very encouraging result given that it is the strongest zone of copper mineralisation intersected so far. The zone is open at depth and to the east. These initial results indicate that the eastern part of Batu Mas is very strongly mineralised in base metals and a number of copper-rich zones have been intersected in the area.

Notes:

1. Gold (Au) Equivalent = gold assay + (silver assay / 47) where the number 47 represents the ratio where 47 g/t Ag = 1g/t Au.
2. Copper (Cu) Equivalent = [(copper assay x copper price x 22.05) + (gold assay x gold price / 31.1) + (silver assay x silver price / 31.1) + (zinc assay x zinc price x 22.05) + (lead assay x lead price x 22.05)] / (copper price x 22.05).