Land leased, geophysical work starts near Pebble

Anchorage-based Alaska Earth Sciences has transformed the firm's first-ever land acquisition into a lease deal with an exploration upstart, Full Metal Minerals.

Alaska Earth, a geological consulting firm with years of experience throughout southwest Alaska, staked a large land position last December adjacent to the Pebble gold-copper-molybdenum deposit.

The company negotiated a land lease deal for the 261 state mining claims with Full Metal Minerals, announced in early March. No financial terms were released on the company's website.

Full Metal can earn 100 percent of the property, called Pebble South, which is located to the southwest and the northwest of Northern Dynasty's Pebble deposit, estimated to contain 26.5 million ounces of gold and 16.5 billion pounds of copper in the near-surface porphyry zone.

"Full Metal Minerals plans on initiating a reconnaissance mapping and regional stream sampling on the property, as well as grid geochemical sampling and reconnaissance IP and ground magnetics. Based on gathered geological, geochemical and geophysical data, drill targets will be identified," the company said on its website announcing the new prospect property.

Full Metal Minerals also holds an exploration option for the Ganes Creek gold property, located about 25 miles west of McGrath in Interior Alaska.

Geophysical work starts soon

Alaska Earth Science will manage the exploration program, Bill Ellis, part owner, told Mining News on March 5. "We'll be starting that soon - the geophysical program in the next couple of weeks."

A crew of about six will set up camp in the area a few miles northwest of Lake Iliamna in southwest Alaska, across Cook Inlet from Homer. Snow cover will allow workers to conduct IP, indicated potential, surveys on a few square miles of the property, which totals about 65 square miles in size.

"If sulfides are there, they show up (using IP)," Ellis said. "We'll be able to cover only the flatter parts of the country this time of the year."

Access will be by helicopter, supported by snowmachines, he said. The geological consultants should be onsite for two to three weeks, Ellis said.

Past work on the claims includes an airborne magnetic survey flown in 1999 by Rio Algom, and a brief follow-up geologic reconnaissance. Some wide-spaced government-generated geochemistry is also available, according to Full Metal's website.

Geological characteristics

Full Metal provided on its website a detailed description of the geological setting for its new prospect, which is underlain by a Late Cretaceous granodiorite pluton and related hypabyssal intrusives which intrude Cretaceous clastic rocks.

Higher elevations above 150 meters are capped by bi-modal Tertiary volcanics. The area is part of the Mesozoic Peninsular Terrane that lies along and flanks a Jura/Cretaceous northern Aleutian Range batholith. Cretaceous to Tertiary intrusive and Tertiary to Recent volcanic rocks intrude the Peninsular Terrane and are products of northwest dipping subduction along ancestral and modern Aleutian trenches.

The Pebble South claims were staked at the conjunction of two regional trends, the Lake Clark Graben and the multi-phased intrusive corridor holding the Pebble Copper deposit. Portions of the Pebble South claim group in the low-lying areas near Iliamna Lake are covered by recent glacial till or drift.

The claims largely cover areas of low to moderate elevation where the mineralized system is likely to be close to the surface and amenable to open pit mining methods.

The northwestern claim group covers the western margin of the Kaskanak Batholith in a similar geologic setting to the main Pebble trend on the east margin of the batholith.

Within the sulfide system defined by Northern Dynasty's IP and soil anomalies, three copper gold molybdenum porphyry systems have been discovered: the Pebble Deposit, the 38 Porphyry and the 52 Porphyry. In addition to porphyry deposits, the 37 Copper-Gold Skarn and the 25 Gold Zone were discovered within the sulfide system.

Additionally, there are other high-intensity IP zones that are potential mineralized centers that have not yet been drilled. The IP-defined sulfide system appears to be open-ended to the south and southwest onto Full Metal's Pebble South claim block.