Baroi Prospect - porphyry copper-gold-silver
Baroi shares many characteristics in common with other major porphyry copper deposits in the region. The prime indicator throughout the Baroi prospect is the intense mineralization of metal-rich quartz sulphide veins and breccias.
In 2002, during reconnaissance work at Baroi in the Central Zone, exceptionally high-grade samples were found containing up to 16.4% copper, 460 grams per tonne silver, and 17.3 grams per tonne gold. As a result, the entire exploration effort moved to Baroi and has been the focus of exploration work for the past three years.
An aggressive geological mapping and sampling program subsequently defined an area containing mineralization of 6 by 4 kilometers. The eastern end, or Far East Zone (FEZ), produced multiple high grade quartz breccia veins at surface - eg, 12 meters @ 6.06% copper, 197.5 grams per tonne silver and 0.72 grams per tonne gold. This zone became the focus of ongoing exploration; an IP survey was conducted, which identified a large conductive body at depth that was believed to be the source of the widespread mineralization in the area.
Select surface channel sample results
Drilling using two man portable rigs - capable of depths to 80 and 300 meters - also produced evidence of this; and some spectacular results were achieved -- eg, drill hole BF 5 returned 85.5 meters @ 2.9% copper, 1.85% zinc, 70.1 grams per tonne silver and 0.22 grams per tonne gold. Further evidence of an underlying mineral source was generated from several of the deeper drill holes, where increasing intensities of alteration and mineralization were observed with depth.
Select drill hole results
Four 600meter holes where drilled in the FEZ in the 1st half of 2006. While the holes did not intercept a porphyry intrusion, they did return some high grade intersections, eg. BF0048 30 m @ 1.12% Cu, 29.4 gpt Ag. The FEZ hosts multiple high grade Cu, Ag, Pb, Zn quartz and breccia veins, within an area of 2 Km by 2 Km, that require systematic drilling in the northeast direction to fully access a potential economic resources of this vein system at the FEZ prospect.
Ongoing Exploration elsewhere in the Greater Baroi prospect, at the Central, South and East Zones where higher gold values had been identified, has produced several targets of major interest.
Central Zone (CZ): The CZ covering an area of approx 2.5 by 2 Km as been subject to detailed geophysical surveys plus soil and rock geochemical sampling and limited drilling.
Multiple diorite, monzonite and dacite porphyry intrusions have also been identified within the area. As a result of work to date, a porphyry target 800 by 400 meters has been identified for future deep drilling. This target is located at the intersection of two NE and NW trending major structures, where quartz veins following the N/W structure have returned some encouraging grades from drill holes:
This CZ porphyry target corresponds to an anomalously low IP resistivity anomaly that is contained within peripheral high chargeability responses. It is now understood that these types of chargeability anomalies at Baroi, are the result of high pyrite/clay content in the rocks. This occurrence often represents a pyrite shell resulting from a porphyry intrusion. Additionally a donut style copper soil anomaly is centered on this target where anomalous Mo also occurs.
These types of geological, geophysical and geochemical signatures are typical of many Cu/Au porphyry deposits and the CZ has excellent potential of hosting such a deposit.
East Zone (EZ): covers an area of approx 2 by 1.5 kilometers
The mineralization in this area is hosted in carbonaceous sediment rock, veins and disseminations. This style and intensity of alteration and vein development is typical of Zn, Pb, Ag lode zones that are encountered around the margins of large porphyry systems. The East zone represents and excellent target for carbonaceous sediment hosted gold and basemetal deposits.
South Zone (SZ): The SZ covers an area of approx 3.5 by 1.2 kilometers and is the least explored of the 4 zones at Baroi. Rocks comprise andesite/dacite valances hornblend andesite, monzonite dykes and carbonaceous sediments that contact with the southern granodiorite basement. Of particular interest in this area are the calcareous limestone's, which offer the potential of Skarn type mineralization.
Mineralization is dominated by basemetal veins, which place it at the margins of the inferred porphyry source in the Central Zone.
Some exceptional high grade channel samples have been recovered from this zone.
Geological Details
Baroi is ideally located where major regional structures intersect, at the margins both of a large circular feature and a granodiorite pluton. This area also contains multiple porphyry intrusions that display intense alteration, diatreme breccias containing mineralized porphyry rocks, several aeromagnetic anomalies, gossanous zones, and a broad vegetation anomaly. The prime indicator of mineralized porphyry is the abundance, throughout a 6 by 4 kilometer area, of metal rich quartz sulphides veins and breccias. Grades in surface and drill cores are the highest the Company has ever encountered in its many years working in Kalimantan. Indeed, the Company believes these grades, and their consistency, to be the best-ever achieved by any explorer in Kalimantan.
Competent Person's Report on the Mineral Exploration Assets of Kalimantan Gold Corporation Limited' - SRK Consulting Engineers & Scientists (PDF, 2.53 mb)
Appraisal and Exploration Summary Baroi and other significant prospects, KSK Contract of Work' - a 43-101 Report (PDF, 12.16 mb)