More drilling slated for Boyongan

Vancouver — The purchase of an additional 10% stake in Philex Mining‘s (PGI-V) Boyongan copper-gold prospect in the Philippines has propelled Anglo American (AUUK-Q) to step up the pace of drilling.

The major has two rigs turning and intends to add four more. Of these, four are slated for delineation drilling at Boyongan and two will be used for reconnaissance work to the south.

“We look forward to an expanded drilling program next year with a target of 15,000 metres of resource definition drilling,” says Gerard Brimo, chief executive officer of Philex. “We also look forward to scout drilling, primarily south of Boyongan, as the debris flow of mineralized diorite porphyry encountered in hole 30 indicates the possible presence of another mineralized porphyry system in the general area.”

The latest drill results confirm that the mineralization at Boyongan extends to a considerable depth. Hole 25 was collared 200 metres south of hole 12 (97 metres grading 0.28% copper and 0.68 gram gold per tonne) and drilled northwards at 60. The hole cut diorite breccia and dioritic intrusive from 327 metres through to the end of the hole at 933 metres, returning 0.42% copper and 0.38 gram gold over 513 metres at 420 metres down-hole. Oxide mineralization comprising cuprite, azurite, malachite and native copper occurred to a depth of 871 metres, followed by a sulphide zone marked by chalcopyrite, bornite, molybdenite and pyrite.

Hole 27 was collared 150 metres south of hole 10 (345 metres grading 0.5% copper and 0.7 gram gold) and drilled northward at 75. The hole hit diorite breccia at 101 metres through to the end of the hole at 663 metres, returning 0.28% copper and 0.27 gram gold over 375 metres from 263 metres down-hole. The sulphide zone was encountered at 260 metres down-hole, comprising mainly chalcopyrite and pyrite.

Collared from the same site as hole 24 (567 metres grading 0.42% copper and 0.68 gram gold) and drilled westward at 60, hole 28 cut 404 metres grading 0.35% copper and 0.63 gram gold from 204 metres down-hole. The hole cut the diorite breccia from 204 metres through to the end of the holes at 608 metres. Oxide mineralization was hit to a depth of 531 metres followed by a zone of propylitic alteration.

Moving 800 metres northwest of hole 6 (365 metres grading 0.81% copper and 1.9 grams gold) and drilled northward at 60, hole 29 returned 49 metres grading 1.18% copper and 0.26 gram gold from 359 metres down-hole.

Hole 30 was collared 800 metres south of hole 6 and drilled vertically. The hole intersected 39 metres of mineralized debris flow, which returned 0.1% copper and 0.65 gram gold over 12 metres from 55 metres down-hole. From 177 metres through to the end of the hole at 219 metres, the hole intersected unaltered sandstones and siltstones.

Holes 31 and 34 were drilled 650 metres west and 500 metres east of hole 30, respectively, with both failing to hit the favourable diorite intrusion.

Holes 32 and 33 are currently being drilled, respectively, 230 metres east of hole 26 (71 metres grading 0.28% copper and 0.29 gram gold) and 210 metres west of hole 8 (abandoned at 284 metres down-hole).

Boyongan lies on the North property in eastern Mindanao, where all the previously discovered copper porphyry deposits occur as clusters farther to the south. The companies are defining a large body of oxide and primary copper-gold mineralization that is covered by later-stage volcanics. High-grade copper-gold values are associated with “high-sulphidation-style” mineralization overprinting an earlier copper-gold porphyry event.

Typically, the mineralized district is part of a northwest-striking belt of pre-Miocene arc basement that has been severely fractured by multiple splays of the major Philippine fault system. Miocene quartz diorite stocks and later subvolcanic andesite porphyries invade late Cretaceous and lower Tertiary rocks. Many of these mineralized intrusions are structurally controlled, occurring along major high-angle faults.

In mid-December, Philex sold an additional 10% equity stake in the project and surrounding ground to Anglo American for US$20 million. Additional payments of up to US$5 million will be required should the metal content of the deposit or of any other discovery within the surrounding claims contain more than 3.6 million tonnes copper-equivalent. The additional payments will be computed by applying US2.51 per lb. copper-equivalent to 10% of the metal content above 3.6 million tonnes copper-equivalent, multiplied by a factor of 0.5.

The deal is expected to close early in 2002, at which point Philex and Anglo American will each hold a half-stake in the project. The major can then earn an additional 30% interest by completing a bankable feasibility study.