Arc obtains more encouraging exploration results at Trenggalek

By Romel S. Gurky

ASX-listed gold miner Arc Exploration Limited (ARX) announced Wednesday more encouraging results from porphyry exploration done together with its JV partner, Anglo American, on the Trenggalek Project located in East Java, Indonesia.

Commencement of scout drilling on the Singgahan Prospect was announced on 19th March 2014. The first scout hole (TRDD055) has been completed and tested a coherent copper-gold-molybdenum anomaly highlighted by soil and bench.

?This hole was drilled to a final depth of 331.7 meters and intersected an altered diorite intrusion beneath a capping of calcareous volcaniclastic rocks hosting diffuse quartz-magnetite-pyrite-anhydrite veinlets and stockworks containing traces of disseminated chalcopyrite and molybdenite mineralization,? the company said in a statement, adding that splitting and sampling of the drill core are in progress and assay results are anticipated within the next 2-4 weeks.

?Further encouraging bench results were also received at Singgahan. Two more benches (SGB-02 and SGB-03) were completed on either side of bench SGB-01, which previously produced anomalous copper-goldmolybdenum intercepts including 140m at 0.045 ppm Au, 386 ppm Cu & 4 ppm Mo. The two new benches produced similar results, including 42m at 0.105 ppm Au, 343 ppm Cu & 4 ppm Mo in SGB-02 and 58m at 0.106 ppm Au, 236 ppm Cu & 2 ppm Mo in SGB-03. These results have confirmed that the coherent copper-gold-molybdenum anomaly persists in bedrock over at least 500m strike-length,? the statement added.

The width and intensity of the mineralization at depth is currently being investigated by scout diamond drilling.

ARX said results were received from a petrology study on 26 core samples selected from hole TRDD054, drilled at Jerambah Prospect late last year. Jerambah is located about 5km west of Singgahan Prospect. ?The results of the petrology study have confirmed that the intrusion breccias and calcareous volcaniclastic rocks intersected in TRDD054 contain porphyry-associated alteration mineral assemblages that include garnet, vesuvianite, secondary albite, K-feldspar, biotite, magnetite, epidote, actinolite/tremolite and tourmaline. Porphyry vein-quartz fragments in the intrusion breccias, extensive anhydrite veining, common traces of disseminated chalcopyrite and molybdenite mineralisation, and narrow structurally controlled zones of overprinting high-sulphidation epithermal alteration (pyrophyllite-dickite-rich) carrying traces of enargite and tennantite/tetrahedrite mineralization, were also identified,? it said. These petrology results are interpreted to indicate that the hole has intersected a peripheral position in a potential mineralized porphyry system. More drilling is planned to test other parts of the prospect, it added.

Further encouraging soil results were received from a large grid-based sampling program conducted in the southeast corner of the tenement area. A new cluster of overlapping spotty copper-gold-molybdenum anomalies reporting up to 348 ppm Cu, 0.095 ppm Au and 59 ppm Mo was highlighted to the north of Jerambah Prospect. These anomalies are similar to those obtained at Singgahan and will be followed-up by prospecting and benching in the coming months.

Meanwhile, petrological work completed on core from TRDD054 drilled at Jerambah last year supports our conclusion that this hole has possibly intersected the periphery of a potential mineralized porphyry system.

A third area, north of Jerambah, has recently returned anomalous copper, gold and molybdenum results from soil sampling and we are now planning some benches to sample the bedrock in this area.

Altogether these three prospects cluster within an area of about 5-km by 3-km. Their geochemical signatures and favourable geological environment support the potential for concealed porphyry systems, the company said.

ARX has a joint venture with PT. Sumber Mineral Nusantara (SMN), an Indonesian company which holds the Trenggalek Exploration IUP tenement that covers an area of approximately 300 km2 in the highly prospective Southern Mountains of East Java.

Editing by Reiner Simanjuntak