Boyongan falls short

Vancouver – After more than two years of continuous drilling, the latest results from Philex Gold‘s (PGI-V) Boyongan copper-gold deposit has prompted operator >B>Anglo American (AAUK-Q) to look for additional tonnage on the surrounding North property in the Philippines.

“According to Anglo, while the Boyongan deposit contains high grades in part, the tonnage anticipated from the oxide zone is unlikely to be sufficient to support a large-scale, long-life operation, while the deep seated sulphide mineralization currently appears to have an erratic grade distribution,” says Philex’s Chief Executive officer, Gerard H. Brimo.

The latest drilling tested the northern, eastern and southern edges of the deposit, effectively closing it off. Highlights include the following:

• Hole 56 – 431 metres grading 0.66% copper and 0.37 gram gold per tonne;
• Hole 57 – 730 metres grading 0.17% copper and 0.24 grams gold;
• Hole 58 – 426 metres grading 0.14% copper and 0.05 gram gold;
• Hole 59 – 657 metres grading 0.37% copper and 0.43 gram gold;
• Hole 60 – 764 metres grading 0.12% copper and 0.14 gram gold,
• Hole 61 – 432 metres grading 0.39% copper and 0.62 gram gold;
• Hole 62 – 548 metres grading 0.26% copper and 0.27 gram gold;
• Hole 63 – 12 metres grading 1.5% copper and 6.2 grams gold followed by 298 metres averaging 0.99% copper and 0.58 gram gold; and
• Hole 63 – 445 metres grading 0.32% copper and 0.34 gram gold.>/li>

Anglo American discovered the covered deposit in September 2000, when hole 6 returned a 365-metre intercept grading 0.7% copper and 1.9 grams per tonne gold. Subsequent drilling throughout 2001 continued to yield impressive numbers, including 393 metres grading 1.58% copper and 2.39 grams gold in hole 15 and 896 metres grading 0.49% copper and 1.57 grams gold in hole 18.

A porphyry deposit hosted by a composite diorite stock, Boyongan was locally affected by a later argillic event, which results in some high grades. The prospect hosts unusually deep supergene oxidation (more than 400 metres locally), which was preserved as a result of being capped by Quaternary sediments and lavas. Malachite, azurite, cuprite and native copper define the oxide zone. Chalcopyrite and bornite dominate the primary copper sulphides.

So far, Anglo has outlined a 500-by-300 metre zone of mineralization grading greater than 1% copper-equivalent with a broader, 850-by-450-metre area averaging greater than 0.5% copper-equivalent.

“Anglo has also informed us that resource estimates incorporating the results of the additional drilling and metallurgical test-work will be available subsequent to an audit to be conducted by an independent consultant, which is expected to be accomplished early in the second half of this year,” adds Brimo.

A January research report tabled by BMO Nesbitt Burns indicates that the preliminary resource on Boyongan is 280 million tonnes averaging 0.93 gram gold and 0.57% copper. Total metal content amounts to 17.8 million oz. gold-equivalent.

Failing to meet the mining giants’ tonnage standards, Anglo is moving forward by looking for additional mineralized porphyries on the property.

“The focus for the first half is therefore to evaluate other porphyry systems within the immediate vicinity of Boyongan, as evidenced by the intercepts of Bird’s Eye porphyry and other geological indications in previous drilling, including the on-going hole 65 northwest of the deposit, which intercepted oxide mineralization.” Adds Brimo.

Collared from the same site as hole 32 and drilled in a westerly direction, hole 65 cur oxidized, argillized and potassic altered medium-grained diorite with minor quartz stockworking from 291 metres to its current depth of 438 metres. Oxide mineralization comprises cuprite, azurite, malachite and trace chalcocite.

Drilling adjacent to Boyongan is continuing with four rigs, while two rigs are currently being transferred for scout drilling at the Bagacay prospect.

“The Anglo exploration program for 2003 includes 28,000 metres of drilling,” says Brimo. “Exploration will intensify on targets immediately to the northwest and west of the deposit, where 10,000 metres of drilling are planned. An additional 6,000 metres is also planned at Magpayang, 3 kilometers south, and at Bagacay, 2 kilometers northwest of Boyongan, during this first half.”

Late in 2001, Anglo American purchased an additional 10% equity stake in the project and surrounding ground from Philex 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 in the surrounding claims, contain more than 3.6 million tonnes copper-equivalent. Currently, Philex and Anglo American each hold a half-stake in the project. The major can then earn an additional 30% interest by completing a bankable feasibility study.

Moving to the western part of Mindanao island, junior Goldminco (GCP-V) has finally launched its long awaited 1,000 metre drill program over the Balabag gold property in the province of Zamboanga. The property was first worked by Rio Tinto (RTP-N) in the late 1990s. Some 300 channel and chip samples collected over a portion of a major ridge returned a weighted average of 10.97 grams gold and 258.69 grams silver. Small-scale mining is scattered throughout and on both sides of the impressive ridge. The highest-grade sample collected to date came from the face of the old Tinago workings, returning 273 grams gold and 109 grams silver.