Northern Dynasty examines a bigger Pebble

A successful drilling campaign in 2005 has prompted Hunter-Dickinson-led junior Northern Dynasty Minerals (NDM-V, NAK-Q) to delay completion of a feasibility study of its Pebble copper-gold deposit, 380 km southwest of Anchorage, Alaska.

The delay comes compliments of the newly discovered East zone, where grades are exceeding those of the project’s main deposit immediately to the west.

North Dynasty envisages eventually exploiting the main deposit via an open pit, followed by a possible underground mining phase to target the remaining deeper mineralization. The company is currently revising its plans to incorporate the East zone into the project’s feasibility study and environmental applications.

The results from last batch of 4 holes sunk on the East zone in 2005 are as follows:

• Hole 5334 279 metres grading 0.62% copper, 0.02% molybdenum, and 1.06 grams gold per tonne;
• Hole 5335 755.8 metres running 0.81% copper 0.02% moly, and 0.44 gram gold;
• Hole 5336 788.1 metres of 0.67% copper, 0.055% moly, and 0.23 gram gold, including a 197 metres of 0.85% copper, 0.05% moly, and 0.33 gram gold;
• Hole 5337 618.5 metres grading 0.83% copper, 0.04% moly, and 0.34 gram gold, including 231 metres of 1.25% copper, 0.04% moly, and 0.37 gram gold.

The company notes that these results, combined with 12 previously drilled and reported holes, “indicate the new porphyry system hosts a substantial volume of mineralized material with excellent copper, gold and molybdenum grades.”

In all, 16 widely spaced holes on the East zone generally returned 0.37-1.7% copper, 0.01-0.05% moly, and 0.11-1.3 grams gold over widths varying from 36-80 metres. The holes tested the zone to depths of around 600 metres, with most terminated while still cutting mineralization owing to drill rig limitations.

The zone remains open at depth and in all lateral directions. An initial resource estimate is expected early this year. The company will also begin a 4-rig, deep-drilling program aimed at fully delineating the zone in March.

Pebble’s main deposit is home to measured and indicated resources totalling 1.6 billion tonnes running 0.35% copper, 0.39 grams gold per tonne and 0.018% moly (or 0.69% copper-equivalent). That translates to 12.7 billion lbs. contained copper, 20.5 million oz. gold, and 629 million lbs. moly.

Another 417 million tonnes of inferred material runs 0.31% copper, 0.42 grams gold and 0.018% moly (0.67% copper-equivalent) – for 2.9 billion lbs. copper, 5.6 million oz. gold and 168 million lbs. moly.

The estimates are based nearly 90,000 metres worth of drilling, and employ a cutoff grade of 0.5% copper-equivalent based on prices of US$1 per lb. copper, US$400 an oz. gold, and US$6 per lb. molybdenum.

At a cutoff grade of 0.7% copper-equivalent, measured and indicated resources amount to 569 million tonnes grading 0.5 gram gold, 0.46% copper and 0.021% moly, or 0.88% copper-equivalent, plus an inferred resource of 143 million tonnes grading 0.56 gram gold, 0.4% copper and 0.02% moly, or 0.85% copper-equivalent.

The Pebble project is situated about 95 km from tidewater on Cook Inlet. The company plans to apply for environmental permits next year. While some environmental groups are opposed to the project’s development, other Alaskans support the project. The company says its goal is to permit the optimum project “with full consideration to all socio-economic, environmental and economic factors.”