Release: Southern Arc: Confirms occurrences of sediment-hosted Au-Ag mineralization on its Sumbawa property
Thursday, February 8 2007 - 01:54 AM WIB
J3 Prospect
The J3 Prospect is situated in the southeastern corner of SA's Taliwang property, approximately 12 km north of Newmont's Batu Hijau porphyry Cu-Au mine.
J3 was discovered by Newmont during first pass regional drainage sampling in 1987 and subsequently targeted by detailed geochemical and geophysical programs. Au-Ag+/-base metal mineralization was identified from a contact zone of a flat lying silicified limestone and an altered volcaniclastic sediment unit. Newmont's channel sampling from a mineralized 2.7 m thick limestone bed averaged 6.75 g/t Au with a maximum of 12.0 g/t Au and 121 g/t Ag. This anomalous outcrop is situated on the eastern edge of a 1.8 x 1.3 km zone of widespread anomalous Au soil geochemistry. The most significant anomaly, within this zone comprises a 700 x 200 m NW trending zone of greater than 50 ppb Au in soil. This is interpreted as an erosional window through unaltered limestone cover re-exposing the mineralized limestone/volcanic contact. Moderate base metal, As, Sb and Mo soil anomalies as well as IP and resistivity anomalies are associated with elevated gold soil geochemistry throughout the area.
Preliminary orientation surveys by SA personnel during November to December 2006 relocated the Newmont discovery outcrop referred to above which SA geologists have named "Hitam Manis" (HM, Indonesian for "Black Sweet"). Outcrop sampling and mapping of the main silicified zone (interpreted as jasperoid ledges) and the peripheral alteration envelope, reported significant high grade Au-Ag channel samples. From 14 rock samples submitted, 6 samples assayed greater than 1.0 g/t Au, including 216.0 g/t Au and 330 g/t Ag over 3.0 metres, 64.0 g/t Au and 52 g/t Ag over 3.0 metres and 10.40 g/t Au & 50 g/t Ag over 3.3 metres respectively (Figure 1). To view Figure 1, please click the following link: www.ccnmatthews.com/docs/sa0207.jpg.
Immediately south of HM, a possible fault offset of similar jasperoidal material returned a value of 33.6 g/t Au and 17 g/t Ag over 2.5m. Assay results from additional surface rock chip sampling peripheral to HM confirm the widespread Au anomalism previously defined by Newmont. Significant rock chip values including 10.1 g/t Au and 14.3 g/t Au have been reported as far as 720 m northwest and 635 m west of HM respectively. Several pods of jasperoid outcrop and subcrop have been mapped up to 2,500 m west of HM coinciding with Newmont's Au-As-Sb soil anomalies.
The geological and geochemical signatures indicate the potential for carbonate replacement Au-Ag mineralization, with a model of steeply-dipping fault/fracture structures channeling Au-Ag rich hydrothermal fluids into receptive flat-lying carbonate basinal horizons.
J6 Prospect
The J6 Prospect is located approximately 4 km west of J3. Mineralization here comprises auriferous base-metal veins hosted within hydrothermal breccia bodies and volcaniclastic and pyroclastic rocks. Trenching of quartz stockwork zones by the previous operator returned anomalous results including 110m @ 1.09 g/t Au (includes 25m @ 2.46 g/t Au). Scout diamond drilling (seven holes totaling 651.3 m) in 1998 by Newmont intersected erratic quartz base-metal sulfide (pyrite-galena-sphalerite-chalcopyrite) sheeted veins and stockworks, with significant intersections of 8.41 g/t Au over 3.9m, 20.8 g/t Au over 0.70m and 10.2 g/t Au over 1.73m.
The current geologic mapping and sampling program over J3 is gradually moving westwards towards J6 and may in time prove a genetic relationship between the two prospects. SA anticipates that following completion of surface evaluation, including limited costeaning and a ground IP-resistivity survey, that preliminary scout diamond drilling if warranted will commence late in the next quarter.(end of release)