The Mansur prospect displays classic porphyry alteration and geochemistry. Extensive work was carried out in the 1990's, including exploration funded by our joint venture partner, Cyprus Amax, which subsequently withdrew because of the unstable political and economic climate in Indonesia at the time.
The Mansur Prospect is located in the NW corner of the CoW, 10 kilometers north of the Lakapoi prospect. Access to the prospect is possible from Palangka Raya to Lakapoi in one day via main roads and logging roads or a mix of river and road transportation. A jungle track provides foot access from Lakapoi to Mansur taking one day. Drilling programs require helicopter support both to mobilize equipment and bring in fuel.
Geological Setting and Exploration Background
The Mansur Prospect was discovered in 1984 by KGC exploration teams following up significant amounts of visual gold in panned concentrates from the rivers draining the area. The Mansur Prospect displays a classic "doughnut-shaped" or annulus shaped soil geochemical copper anomaly about 1 kilometer in diameter.
Figure 5: Mansur Copper Soil Anomaly Map
In 1994, KIC drilled 11 diamond drill holes and then in 1997, in our joint venture with Cyprus Amax, another 7 holes were drilled. Most of the existing drill holes were located within the low-grade "doughnut hole" or central core while the best copper grades outside this area remain untested at the margins. In retrospect, it seems that Cyprus Amax may have applied the wrong geological model i.e. they did not understand South Western Pacific style of mineralization.
Consequently, this core zone gave inconclusive results, although intercepts up to 40m @ 0.24% Cu and 0.24 gpt gold were intersected in early shallow (100m) drill holes at the margins of the copper anomaly.
However, one hole in the first round of drilling intersected 6.12 gpt gold across 2 metres.
Geophysical interpretation also indicates that this untested area potentially contains a high metal (possibly copper and gold) content at depth.
The Mansur Prospect has been well exposed by regional erosion processes, making it easy to drill by using the Company's cost effective man-portable drill rig. This shallow depth will enhance potential mine economics due to the lower strip ratios.
Associated with the Mansur Prospect is a strong magnetic anomaly mirroring the overall circular structure. These also coincide with a number of mid-Tertiary intrusions at the north-eastern corner of the CoW. Copper-gold mineralization is hosted in a diorite intrusion and subsequent feldspar porphyry dykes that have been emplaced into a sequence of interbedded siltstone, arenite and chert sediments.
The diorite has undergone prograde biotite-magnetite ± quartz ('potassic') alteration. The sulphides are dominated by pyrite and chalcopyrite, with lesser abundances of bornite and trace amounts of sphalerite and galena.
Also mirroring this circular area of highly anomalous copper geochemistry (>500 parts per million "ppm") is a high chargeability/low resistivity geophysical anomaly. This zone surrounds a high resistivity, low copper grade potassic altered core of a diorite intrusion which is expressed as a zone of anomalous gold in soils; in addition to chlorite-sericite alteration and associated chalcopyrite-molybdenite veinlets occur around the periphery of the intrusion and extend into hornfels sediments.
The coincidence of a halo of high copper in soils with a zone of high IP chargeability around a barren to low grade central core zone, with minor local retrograde (sericite-chlorite) alteration, is characteristic of porphyry copper systems that have been well exposed by deep erosion.
Present exploration in the Mansur Prospect area is focused on the yet to be drill tested, high copper and high IP chargeability zones. These zones may be related to high-grade mineralization in fault contacts of a porphyry intrusion at depth.
Exploration Work to Date
Estimated Expenditure to Date
- Airborne geophysics and satellite image interpretation.
- Geological mapping/sampling.
- Grid based soil geochemistry over a 7.8 Km2 area, 1251 samples.
- 11 shallow diamond drill holes totaling 1068 metres in 1994.
- Grid based ground magnetics and Induced Polarisation (IP) surveys totaling 47 kilometres in 1996
- 7 medium depth diamond drill holes totaling 2,114 metres.
- Costeans and 3 adits.
- Trenching and sampling currently in progress.
- US$ 1,500,000 including Cyprus Amax's expenditures in 1996.
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)