Sabalong Project Activities

Updated: 290611

Southern Arc acquired the Sabalong property in late April 2007, and shortly thereafter commenced exploration activities by starting with socialization meetings for senior regency officials in Sumbawa Besar, the regency administrative centre. This was followed by a socialization meeting with local government officials and village elders in Lantung Aimual Village, where the company initially set up its Sabalong field office. The field office and mess was subsequently moved to Lito Atas, which permits easier access to the main Lito prospect.

Socialization was followed by field activities that included a BLEG sampling program, which then developed into geological mapping and rock chip and channel sampling, and selected hand trenching.

The Company was granted an IUP for the Sabalong property on December 17, 2009. Subsequently, Southern Arc entered into an option and joint venture agreement with Vale S.A. To exercise its option, Vale must fully fund the advancement of the Sabalong property, through to and including the completion of a Bankable Feasibility study, at no cost to Southern Arc.

Most Recent Activities

Upon entering into the Vale joint venture, Southern Arc resumed exploration activities in mid-December 2010 with the opening of the fully-staffed Lito Atas office. Surveying commenced and a 62.5 line-km grid (4.5 km by 3.5 km) covering the main Toyang and Lito prospect areas was cleared. A ground magnetic survey along a total of 106.3 line km was completed at the end of February over the Lito, Toyang and Gempang Budi prospects. data modeling and interpretation of the acquired data by a consultant geophysicist has indicated three main magnetic anomalous zones, indicating inferred near-surface magnetic bodies. A deep dipole-dipole induced polarization (IP)/resistivity survey was subsequently completed at the end of June and the data modeling and interpretation of the acquired data by a consultant geophysicist is under.

An airborne magnetic survey is also being organized. The equipment to conduct the airborne survey is already in-country with only certain bureaucratic and administrative requirements to be completed soon. The subsequent drilling of inferred lithocap-related porphyry Cu-Au targets is planned to start in late Q3 2011.

Mapping also continues in the southern part of the Toyang and Gempang Budi areas to record the extent of exposed epithermal mineralization. Samples continue to be collected for clay spectral analyses, which will aid in the determination of alteration zoning within the three inferred anomalous zones. Environmental baseline studies are currently under way.

Past Activities

Prior to the formation of the Vale joint venture, work on the property by Southern Arc involved carrying out limited ground traverses over a historical molybdenum soil anomalism in the NE of the property in August 2008.  It had been postulated that elevated molybdenum values might represent seepage through the inferred porphyry lithocap.

Previously, however, exploration by the company during March 2008 had focused on hand trenching across previous Au-anomalous outcrops at Toyang, along with vuggy silica exposures at the Lito high-sulfidation prospect (see Sabalong Geology and Alteration map). A total of six trenches (TR-03 to TR-06 and LT-01 to LT-03) totaling about 275 m in combined length, realized a total of 114 CH samples.

Hand trenching at the Toyang prospect was completed with three trenches completed across previous Au-anomalous outcrops. Depth to bedrock varied from 0.5 m to 2.0 m, with sample intervals of 1.5 to 2.0 m (see Toyang trenching map).

Trench TR-04, 34.3 m long, encountered argillic altered dacitic lithic tuffs with irregular hairline to sheeted crystalline quartz vein and veinlets. Trench TR-05 was 30.4 m in length, and exposed intensely argillic-silicic altered dacitic lapilli tuff with random quartz veinlets. Trench TR-06 was 53.0 m in length, and intersected argillic-silicic altered dacitic lapilli tuff with hairline quartz veinlets and locally intense silification.

At the Lito Prospect three trenches were completed in March over vuggy silica and transitional silica exposures, along with subcrops areas (See Lito trenching map).

Trench LT-01 was 54.3 m long, and intersected predominantly advanced argillic altered dacitic tuffs with localized zones of quartz-limonite (ex-sulfide) veinlets and transtional silica. Trench LT-02 was 52.0 m long, and exposed advanced argillic altered dacitic tuffs, with zones of transitional silica and vein quartz breccias/cataclasites.  Trench LT-03 was 50.6 m long. The majority of the bedrock encountered was transitional silica with zones of vuggy silica.

Rock exposures at Toyang were tied into the DGPS-surveyed base line. Mapping identified limited occurrences of pseudo-vuggy silica (vuggy silica later overprinted by advanced argillic and/or silicification events) among the ubiquitous advanced argillic and argillic-altered dacitic pyroclastics. Exploration in February focused on hand trenching across previous Au anomolous outcrops. Three trenches were excavated (TR01 to TR03) with depth to bedrock varying from 0.5 m to 1.5 m and samples taken at intervals of 2 m [see Trenching map].

TR01 was 48.3 m in length and exposed intensely fractured argillic altered dacitic lapilli tuff with localized E-W quartz veining.

TR02 was 83 m in length and exposed intensely argillic-silicic altered dacitic lapilli tuff with random quartz veinlets.

TR03 was 63 m in length and exposed intensely argillic-silicic altered dacitic lapilli tuff with random quartz veinlets. 

In late July 2007 Southern Arc fielded four survey crews on the Sabalong Property. They commenced a detailed regional BLEG sampling program at an approximate density of one sample per 1.1 km² together with semi-detailed prospect evaluation in and around historical Rio Tinto (RTZ) high-sulfidation prospects.  The high-sufication epithermal mineralization and peripheral alteration suites were noted in dacite porphyry intrusives and polymict breccia exposures. Basinal limestone and intermediate pyroclastics predominate in the area mapped to date (See Sabalong Geology Plan on Sabalong maps page).

BLEG sampling by Indonesian geologist and field assistants in the
northern part of the Sabalong property.

The regional BLEG program was completed in mid-August.  In general, pyroclastic lithologies encountered in the southern half of the property are considered non-prospective with only regional propylitic alteration assemblages and rare, shear-controlled quarts veins less than 1.5 m in width encountered.

Following the completion of the regional sampling program, field crews undertook a rapid rock chip sampling program over historical RTZ high sulfidation prospect areas encompassing an area of 4 by 3 km. The area of interest comprises widespread argillic alteration with lesser advanced argillic and vuggy silica assemblages. Possibly, the eastern zone (Lutuk Gempang Budi-Olat Toyang-Lebangkang is controlled by a northeast-trending structural corridor. In September, a DGPS base line was being established along this orientation for survey control.

A total of 16 ex-RTZ drill holes were located, with information still readable from the cemented collars. From the holes located to date the average depth of these holes was 50 metres, with only a single hole reaching 204.5 metres. In the Olat Toyang drill holes were cored along a fence pattern. Southern Arc continues to seek information on RTZ drilling and ground geophysical data from a number of sources.

Initial Southern Arc exploration activities activities related to the Sabalong Property involved socialization meetings at Sumbawa Besar with regional and local government agencies and later at Sabalong with communities located around Lebangkar. Southern Arc mineral exploration activities were received very favourably by both government agencies and the local populace.

A regency-level forestry team late in May 2007 carried out a survey of the property to establish boundaries and areas of designated protected and production forest areas. This was the first stage in obtaining the mandatory permit from the Forestry Planning Body (Badan Planologi). In the meantime, Southern Arc compiled historical Newmont and RTZ exploration data.

Southern Arc making a presentation in Sumbawa Besar to the
local regency officials and other interested community groups.