West Lombok Project Activities

West Lombok, Southern Arc’s primary asset, has district-scale potential with drill-proven, high-grade, gold-rich copper porphyry and epithermal vein systems over three large prospects: Pelangan, Mencanggah and Selodong.

Historical geological mapping and geochemical results within the West Lombok property confirmed the presence of anomalous gold, silver and base metals from low sulfidation epithermal and high sulfidation epithermal mineralized systems. Exploration by Newmont in the late 1980s and early 1990s within the West Lombok area noted that alteration lithocaps are commonly above mineralized intrusions or above known or untested porphyry gold-copper systems. The presence of both high sulfidation and low sulfidation vein outcrop and hill talus in the vicinity, along with good prospectivity in the Pelangan and Mencanggah prospects, suggested that the West Lombok property has significant potential for hybrid high-low sulfidation systems or structurally controlled, high sulfidation copper-gold systems.

 
View over the Pelangan area

Southern Arc's exploration team started full-scale activities on the West Lombok property and completed setting up its field office and base of operations in the community of Pelangan at the start of 2006. A large field camp capable of accommodating up to about 100 persons was subsequently established on land the Company purchased at Selodong.

Two teams are carrying out two separate tasks: Diamond drilling of the mineralized structural breccias (MSBs) and the other focused on regional geomapping and geochemical sampling to extend the known surface mineralization. An airborne geophysics survey over the enitre property is planned within about two weeks. This new survey will take advantage of the latest technologies and numerical interpretation modeling software to provide much more detailed information, particularly in assisting to locate inferred blind porphyry targets.

Drilling

Phase 1 drilling at the Pelangan Gold prospect was completed in 2007. Phase 2 drilling at Pelangan is under way at using five drilling rigs capable of drilling to 450 m, with another drilling program on the Mencanggah Epithermal District immediately to the south.  The company's exploration activities at West Lombok are very intense and aggressive, with at least 150 workers hired from the nearby communities to construct drilling pads and access roads ahead of the drilling rigs while drilling is under way.

Getting some of this work completed initially was hampered by unusually inclement weather, causing landslides and making earthworks difficult to accomplish. Furthermore, initial start-up of the drilling program was delayed while logistics for delivery, operating and maintaining a large number of drilling rigs as well as support activities, geomapping, etc. were ramped up. Delivery of the motors for the drilling rigs has been delayed as the factory that manufactures the motors was damaged by the large tsunami in Japan in March. However, the whole operation is being streamlined as the people in the field become accustomed to their roles.

Phase 2 drilling results for 14 holes at Pelangan have been released (see Pelangan gold prospect activities page), and assay results are being issued as soon as is practically possible as they are returned from the laboratory. Results, however, will not necessarily be released in the same sequencing of drill hole numbering because completed assays might not always be ready and returned by the laboratory in the same sequence, although effort will be made to try to keep the results numbers in a logical sequence. Each hole is unique in terms of the length of intercepted mineralization and other factors such as down-hole conditions, and hence some take longer or shorter periods of time to be drilled and subsequently processed by the laboratory.

Typically, however, the time from the start of a hole to assay results becoming available varies according to a number of variables: length of hole, material being drilled and related downhole conditions, quantity of core to be processed and assayed, ocassional equipment maintenance or breakdowns, laboratory work load and, occasionally, weather.  For the current medium-depth holes up to about 250 to 300 m long it is expected that on average the following times are expected, assuming no complications during drilling and the laboratory free to complete the assay process in a timely manner: 10 to 12 days of drilling, 3 days for logging and processing the core for sending to the laboratory and another 14 days for laboratory assays to be completed. Drilling rates average about 20 to 25 m per day for each drilling rig.

Pelangan Gold Prospect

Phase 1 geo-drilling was completed at the Pelangan prospect in 2007, together with semi-detailed geological mapping and outcrop channel sampling of sub-parallel vein structures at Lala, followed by the start of Phase 2 drilling in late August 2008, which was temporarily suspended after two holes were completed, until the company obtained an IUP for the property.

With the IUP for the West Lombok having been granted to Southern Arc, three diamond drilling rigs have continued Phase 2 drilling since late March. The first of these holes was completed by the first weekend of April, with a total of 18 holes completed since and another five holes in progress.

Initially the drill rigs are testing for high-grade ore shoots at the central and south Raja target, and testing the north Raja area and the Tanjung lode below Phase 1 drillhole TDG002. The drill rigs are capable of coring to lengths of 400 to 450 m, which is adequate to cover the scope of this drilling phase. The Raja MSB target is only one of five major zones of mineralization delineated at Pelangan, comprising an aggregate strike length of approximately 4.6 km, all of which are targeted for inclusion in the current drilling program.

Currently, drilling at Pelangan is being dedicated to the MSBs, however it is planned to start drilling for possible blind, inferred porphyries later in the year. Detailed geological mapping and geosampling continues concurrent to the drilling to extend the known MSB mineralization.
more on Pelangan activities...

Mencanggah Epithermal District

Concurrent with the drilling programs at Pelangan and the SIC, DGPS mapping and rock chip and channel sampling at Mencanggah has been carried out since the autumn of 2006. Sampling and geochemical mapping on the Mencanggah prospect identified Au-Ag epithermal quartz veining extending over a broad area of at least 6.5 km long by up to 4.5 km wide, including an aggregate proven strike length of more than 15 km, overprinting advanced argillic alteration and silica ledges in a broad area along with the presence of inferred porphyry copper-gold style mineralization. The epithermal gold targets are drill ready and the drilling program is starting by testing a large number of MSB targets at shallow depths (approximately 50 to 150 m below surface) with three drilling rigs operating initially. The aim is to complete a NI 43-101 compliant resource estimate within 18 months of the start of drilling at Mencanggah.

Spectral analysis of surface rock alteration together with information gained from the drilling programs will also assist in the targeting of the inferred porphy mineralization below the advanced argillic capping. Furthermore, detailed DGPS surface mapping will be undertaken between Mencanggah North and Pelangan South. Four drilling sites have already been identified at Mencanggah for pad preparation.

The drilling rigs are on site. Two of the rigs are capable of drilling to hole lengths of approximtaely 400 m. The third rig has a capability of drilling to hole lengths of 700 m and eventually will be used to test for inferred porphyry mineralization. Another two rigs will be commissioned soon so that a total of five drilling rigs will be operating at Mencanggah. This is because it will allow the company to catch up on the time lost in getting drilling started at Mencanggah due to the inclement weather and, moreover, the size of the area to be drilled is very large.
more on Mencanggah activities...

Selodong Intrusive Complex

At the southeastern end of the West Lombok property, Southern Arc defined the 14 porphyry copper-gold targets that make up the Selodong Intrusive Complex (SIC) by geochemistry, geophysics and alteration mapping. Subsequently, exploration activities focused on the Phase 1 deep diamond drilling program, which was completed in early September 2008, targeting the gold-rich copper porphyry prospects with over 17,800 m of diamond drilling.

Two of the targets were tested by Southern Arc with 21 drill holes, returning significant intersections that included 166.2 m @ 0.52% Cu and 0.85 g/t Au and 102.3 m @ 0.50% Cu and 1.05 g/t Au. The geochemistry and geophysical surveys, mapping and subsequent Phase 1 drilling program  have indicated porphyry copper-gold district mineralization.

Southern Arc is continuing to further evaluate and advance this large prospect. During 2011 at least 3,500 m of diamond drilling of defined targets will be carried out. Ground IP/resistivity surveys will be undertaken where warranted, complimented by spectral analysis work to establish vectoring of further porphyry Cu-Au drill targets.
more on Selodong activities...