Roko Gold Project, Halmahera, Indonesia: Major Epithermal System Outlined
- Recent exploration results enhances prospectively for gold mineralisation
- Host rocks, hydrothermal alteration and structural setting similar to nearby "Gosowong" bonanza gold deposit
- 3 km corridor hosting high level epithermal quartz veining and altered intrusive has been discovered
- Most prospective target zone for bonanza gold mineralisation expected to be at a deeper level
- Preliminary soil sampling results confirms anomalous pathfinder elements
- Surface exploration continues in preparation for diamond drilling program
Work to date on the Roko Project, including mapping, gridding, channel sampling and trenching, has resulted in the discovery and surface definition of a 3 kilometre long structurally-controlled target corridor which is considered to be associated with a major, deep crustal, north-east trending transfer fault (The Tiabo Lineament). The Tiabo Lineament, which passes through the Roko concession area, is considered an important regional geological feature associated with numerous occurrences of gold and silver (including Reliance's Roko and Kapa Kapa project areas). The major Gosowong-Kencana gold mining camp is interpreted by the company's expert structural geologists to be associated with another deep crustal lineament which parallels the Tiabo Lineament.
The 3-kilometre Roko target corridor is host to igneous intrusions, multi-phase hydrothermal alteration and high level epithermal quartz vein mineralisation considered highly prospective for hosting gold and silver mineralisation.
Detailed mapping at Roko West has outlined a north-west trending zone of multiple chalcedonic quartz veins and strongly siliceous eruption breccias with associated hydrothermal alteration along the south western slope of Sesa Hill (Figure 1). Most veins trend north-west with subsidiary north-south vein splays. The breccias occur mainly in an area central to Sesa Hill and are interpreted to represent an eruptive hydrothermal breccia pipe. Eruption breccia pipes are known to be intimately associated with mineralised epithermal vein systems. The Toka Tindung Mine (1.7 Moz Au) in Indonesia is centred on an eruption breccia and epithermal vein systems at McLaughlin (4 Moz Au) in USA, Twin Hills in Australia and Hishikari (9 Moz Au), Japan, grade upwards into outcropping eruption breccia pipes.
The main zone of veining and alteration so far mapped at Roko West is approximately 1 kilometre in length and 100-200m in width. Banded chalcedonic veins at Roko East outcrop along the banks of the Ira River. The zones are considered to be very prospective as historical channel sampling along the banks of the Ira River retuned 8m @ 1.6 g/t Au which is strongly anomalous for an epithermal vein at such a high level in the system.
Fig 1 Plan view of Roko West and Roko east prospect with location of mapped quartz veins
A grid-controlled soil sampling program has been completed at Roko West and is currently being extended a further 1000 metres to the west where float samples of hydrothermally altered porphyry with quartz-sulphide veins have recently been encountered. Rock samples have been submitted to Intertek Laboratories in Jakarta for assay and results are awaited. Soil samples are collected in the field and taken to Reliance's regional office to be dried. As a preliminary indication of metal content, a portable, hand-held Niton XRF analyser2 is used to determine the concentration of epithermal pathfinder elements such as arsenic (As) and antimony (Sb).
The Niton results show that Sb and As, are anomalous along the strike length of the north-west trending zone of alteration/veining and are highest adjacent to the interpreted eruptive breccia pipe.
Rock grab sampling of quartz veins at Roko has encountered anomalous gold values of between 0.1 - 2.1 g/t Au. Previous reconnaissance channel sampling at Roko East returned 8m @ 1.6 g/t Au. According to the geological model developed for the Roko veins, bonanza gold values are not to be expected at surface but may occur at deeper levels within the system; in zones of fluid mixing and/or boiling. All current indications at surface are that the Roko mineralisation outcrops at a very high level in the hydrothermal system. For example siliceous sinter has been encountered on the slopes of Sesa Hill, evidence of a surface outpouring of hydrothermal fluids (eg similar to The Geysers geothermal field and sinters at the nearby ex-Homestake McLaughlin Mine (4Moz Au) in California).
Geological work at Roko has identified a structurally-controlled corridor with many similar characteristics to the nearby Gosowong deposits. Both have north-west to south-east and north-south trending epithermal quartz veins with associated hydrothermal breccias and sulphide mineralised porphyries. The high-grade veins at Gosowong occur at a lower level in the hydrothermal system. The exploration focus at Roko is to delineate epithermal veins within the prospective corridor and then to drill them at the appropriate level to discover high-grade gold and silver mineralisation.
To maximise the likelihood of a successful drill program further surface exploration is planned such as ground geophysics (resistivity, IP, Magnetics) across the main alteration zones at Roko. These surveys will assist with better defining zones of silicification / epithermal quartz veining, especially in areas of poor surface exposure and will also provide a 3-dimensional view of the mineralising system to best target the drilling, in what is a large epithermal system.
The Company has a portfolio of five mineral tenements covering 68,000 acres on the islands of Sulawesi and Halmahera in East Indonesia. The projects offer both exploration potential and an existing resource base. All five projects are adjacent to or along strike from operating gold mines or identified gold resources with similar geology and structural feature.
The Company is active on four of its five Indonesian gold projects; currently drilling on the Tanoyan Gold Project and conducting surface exploration programs on the Palopo Gold Project, the Kapa Kapa Gold Project and the Roko Gold Project. All of the projects have easy access via paved and/or gravel roads and regional infrastructure is good.
This press release has been reviewed and approved by Mr. John Levings, B.Sc., FAusIMM, director of Reliance Resources Limited and a Qualified Person as defined by National Instrument 43-101, under whose direction the exploration programs are being carried out.
Media Information, contact:
Scott Emerson, Chairman and Director
Investor Information, contact:
Mike Kordysz, Investor Communications
The statements herein that are not historical facts are forward-looking statements. These statements address future events and conditions and so involve inherent risks and uncertainties, as disclosed under the heading "Risk Factors" in the company's periodic filings with Canadian securities regulators. Actual results could differ from those currently projected. The Company does not assume the obligation to update any forward-looking statement.
- http://www.infomine.com/index/pr/PB164711.PDF Technical Report on the Gosowong Property in North Maluku Province, Indonesia dated December 31, 2011
- Portable XRF instruments are generally not sensitive enough to accurately detect low concentrations at which gold can occur in soil (<10ppm Au). Pathfinder elements are useful to define zones of hydrothermal fluid flow which may host gold mineralisation. The soil samples collected in this work will eventually be assayed for gold at a commercial laboratory