Tawi-Tawi Copper-Gold Porphyry Deposit

Benguet Consolidated drilled the Tawi-Tawi deposit (formerly known as Que Sera) in the 1970’s where they completed 58 holes totaling 32,488m. By 1983 a total of 92 holes (40,618m) had been drilled on the property. However of these 92 holes, data are only available for the original 58. In addition to exploration drilling, there was a shaft sunk to 138m and 963m of lateral adits were developed and sampled to further investigate the deposit. Most holes were drilled with a vertical orientation to a maximum depth of 1,010m, with 10 holes bottoming in significant mineralization indicating that the dimensions of the deposit has not been closed off at depth. Benguet generated a polygonal resource model in 1975 of 225Mt @ 0.4% Cu, 0.3 g/t Au with molybdenum credits.


Historic Resources

A historic (non-JORC compliant) resource of 225 Million tonnes @ 0.40% Cu with significant gold (0.25 g/t) and molybdenum credits was calculated in 1975 by Benguet from results of 58 diamond drill holes. Sillitoe and Gappe (1984) quote an estimate of 159 Mt @ 0.39% Cu, 0.16 g/t Au.

A computer-generated (Geodata) wireframe block model by Motton (2006)1,2 estimated a resource of 261 Mt @ 0.40% Cu.

 

Motton (2006)2 also noted that:

• Although the main ore body appears to commence at approximately 200 metres depth, the overburden is reported to grade conservatively at between 0.2 and 0.3 % Cu.

• Significant improvement can be made to this figure with today’s accepted modeling techniques and data verification / validation.

• The deposit appears to be open in three directions (east, west and south) which offers significant potential to add to the existing resource base.

• Scout holes to the east and west of the main ore zone show significant Cu grades outside of the ore resource model.

• Better assay techniques will further enhance the gold and molybdenum credits which are poorly defined and not thoroughly analysed.

Diagram shows a three dimensional model of the Tawi-Tawi drill holes showing that most of the drill holes are drilled vertically.

The Bolo Copper-Gold Porphyry and Epithermal Gold Target

Previous Work

Alluvial gold and high-grade epithermal gold-bearing veins were worked on the Bolo property in the 1920s to 1940s. Early field work by Worley in the mid 1960’s highlighted the extensive area of alteration that occurs at Bolo.

Exploration by Benguet conducted in the mid 1970’s discovered a copper-mineralized biotite altered, diorite porphyry, similar to Tawi-Tawi but exhibiting a distinct overlying epithermal gold system.

Benguet drilled 9 holes for a total of 2,131.5 m that defined a widespread area of copper mineralization, including a 20 to 100 metres thick blanket of copper oxide mineralization. Adits and tunnels driven into the deposit encountered porphyry copper mineralization along much of their length and significant assay data is available in old records.

In 1987, BMG and BHP geologists collected 44 rock chip samples from epithermal veins and alteration zones. The samples contained from 0.08 to 5.36 g/t Au and averaged 1.09 g/t Au.

In his report on the area, Motton (2006) concluded that the area has considerable potential for economic epithermal gold and copper-gold porphyry mineralization.

Disseminated and vein gold mineralization is reported to occur over an area of 4 km2. It is uncertain how the area was estimated, but it may be based upon the extent of alluvial gold workings. (Motton, 2006)


Recent IP geophysical work has shown a strong chargeability anomaly directly between the Bolo and Tawi-Tawi Deposits indicating that the mineralization may be continuous.

The main IP anomaly between the drilled areas is shown above.

1 These tonnage and grade calculations are not NI 43-101 compliant and therefore should not be relied upon.

2 Motton, N, 2006, Internal technical report prepared for Solfotara Mining Corp. on Tawi-Tawi property.