Junior hunts for White Gold lookalike

Nearly a half century ago, John S. Brock ventured into Yukon Territory to explore for hardrock minerals. The young geologist soon found himself involved in Anvil Mining and Dynasty Exploration's discoveries that led to the development of Faro, which became the world's largest open-pit lead-zinc mine.

"I was just a kid then, and I thought, 'This business is really easy,' " Brock recalled. Today, the longtime explorationist knows better.

During the past 48 years, Brock has participated in numerous mineral discoveries in Canada, including Yukon Territory, and around the globe. Now, Brock is back in the Yukon, hunting for gold in some of the same places where he once searched for copper deposits.

"I participated in the Casino discovery in 1969, but we were looking for copper-molybdenum mineralization and ignoring the potential for gold," Brock told Mining News in a recent interview.

The veteran geologist currently serves as president and CEO of Pacific Ridge Exploration Ltd., a long-lived junior with five exploration projects in Yukon Territory, bust his current focus is the historic Klondike area and the emerging White Gold mining district south of Dawson, Yukon.

Pacific Ridge owns the Mariposa, Gold Cap, Polar/Stewart and Eureka Dome projects, which are all prospective for gold, and Fyre Lake, a long-held copper-gold property in the Finlayson mining district of Southeast Yukon. The company also owns the Baker Basin uranium project in Nunavut where exploration is on hold until uranium prices increase.

Focus on Mariposa

Earlier this year, Pacific Ridge appointed Janice Fingler, a field geologist with more than 25 years experience and a string of exploration successes in South America and Nunavut, as its vice president of exploration.

Fingler will lead the 2011 exploration campaign, which is centered on the Mariposa Project. Located in the South Klondike-White Gold camp, Mariposa's southwestern corner is about 12 kilometers, or 7.5 miles, northeast of Kaminak Gold Corp.'s Coffee Creek Project.

In 2010, Kaminak reported eight separate and closely-spaced gold discoveries at Coffee within a 10-kilometer, or 6-mile, strike length in a first-ever drill program on the 607-square-kilometer, or 234.4-square-mile, property. Kaminak is continuing its exploration of the Coffee Creek property this year with C$15 million budgeted for up to 40,000 meters of drilling and collection of 10,000 new soil samples.

Exploration of Mariposa is about 18 months behind Kaminak's campaign at Coffee, according to Brock. During Pacific Ridge's first full-season on the property in 2010, the junior completed initial mapping, collected 3,000 soil samples on a grid covering Mariposa's original 203 mineral claims and dug five widely spaced trenches resulting in 1,600 meters of excavation and sampling that returned significant gold and molybdenum values.

Another White Gold/Coffee?

The Mariposa claims also lie just 15 kilometers, or about 9 miles, to the southeast of the White Gold property where Underworld Resources Corp defined a 1-million-ounce-plus gold resource before being taken over by Kinross Gold Corp in 2010.

Unlike the White Gold and Coffee projects which were initially identified as significant gold prospects by Dawson prospector Shawn Ryan of Ryanwood Exploration, the Mariposa property came to Pacific Ridge's attention through a syndicate led by longtime Yukon explorationist and placer miner, Gordie Richards.

Pacific Ridge optioned the 50 square kilometers, or 19.3 square miles, of original claims in August 2009 at the beginning of staking rush that followed confirmation of Underworld Resources' White Gold discovery, and quickly expanded the Mariposa property to encompass 967 claims covering 190 square kilometers, or 73.4 square miles within a regional major northwest trending structural corridor hosting gold and copper deposits.

Initial exploration of Mariposa has successfully defined six gold and multi-element anomalies within a 14-kilometer, or nearly 9-mile, strike length of a geological setting that bear a distinct resemblance to the White Gold/Coffee Creek-style gold mineralization. Four of the geochemical anomalies - Skookum Jim, Big Alex, Hackly and Maisy - remain open for further definition and expansion, Brock said.

A century of placer mining

All of the streams draining the Mariposa property are known to contain placer gold, of which Scroggie Creek has a 100-year-plus history of placer gold production which continues today. Scroggie and Mariposa creeks, which traverse the Mariposa property, are old placer gold creeks first discovered in 1898 and extensively mined by hand with the aid of steam boilers and points in the early 1900s, according to Geological Survey of Canada records.

Brock said the two creeks have seen the longest continuous placer gold production in the Klondike.

Richards has mined placer gold with partners along Scroggie Creek and along Mariposa Creek, a tributary to Scroggie, for 12 years.

Though early records have not been thoroughly researched, Richards reported in 2005 that at least "100,000 ounces of raw gold with a fineness of 905 has likely been produced from Mariposa and Scroggie creeks between the top of Mariposa Creek and a point 4 kilometers below the airstrip on Scroggie Creek," which is the area where most of the historic cabins, shafts and diggings are located on the Mariposa property.

Richards noticed the rough-edged, or "hackly," characteristics of the placer nuggets recovered in the headwaters of Mariposa Creek.

Geologists believe that the presence of this type of placer gold could indicate that its lode sources are nearby.

"The fragility of the pristine gold crystals projecting from the clasts (in the hackly placer nuggets) suggests that they were not transported far following their introduction into the fluvial system. Consequently, a source on adjacent hillside is suggested," according to GSC Current Research Report 2003-A1.

Pacific Ridge also reports that the six gold geochemical anomalies it defined on the property are located on hillsides proximal to the hackly gold placer locations.

Gold at 'Skookum Jim'

At the largest of the gold-in-soil anomalies on Mariposa, the 3.5-kilometer-long-by-650-meter-wide 'Skookum Jim' anomaly, the presence of gold was confirmed in 2010 with grab samples of rock returning up to 8.1 grams per metric ton gold and composite rock samples from trenches returning up to 1.25 g/t gold over 30 meters.

Pacific Ridge said the emerging geological setting of the Skookum Jim target exhibits several similarities to the Kaminak Coffee Creek discoveries where gold occurrences are proximal to anomalous gold-in-soils, well-altered rocks with an abundance of silica, oxidized pyrite (limonite) and major northerly trending geologic structures.

Four kilometers west of Skookum Jim, one trench was completed in 2010 within the Maisy May target, where anomalous gold-in-soil values occur in an area of highly silicified quartz mica schist float that has been traced 400 meters to the northwest.

Samples of siliceous float returned significant gold and copper values as well as anomalous values in bismuth, molybdenum, arsenic and antimony.

Based on both the extent and tenor of these results, Brock said the Skookum Jim anomaly is a priority drill target in 2011.

Drilling set for Mariposa

Pacific Ridge has allocated C$3 million for phase 1 exploration that includes 4,000 meters of diamond drilling, geophysical surveys, along with more geological mapping, deep-auger soil sampling and trenching with a portable backhoe and. Contractors have been engaged for both drilling and helicopter support services, and the company expanded its technical team.

Fingler, who assisted the junior with its 2010 exploration program as a consultant, told Mining News that Pacific Ridge's geological team now has more than 100 years of combined experience, mostly in the field.

"We have a century of experience, and what we like about our collective experience is that John has a broad leadership background in discoveries and moving projects along quickly while using shareholder resources wisely, and Jeff (Kellner) and I have been involved with many projects over the years, from the ground up," Fingler said. Her past assignments include work on the early stages of the Collahuase copper discovery in Chile and on the Meadowbank and Meliadine gold discoveries in Nunavut.

Integrated exploration activities at Mariposa this year will include both detailed follow-up of gold-in-soil anomalies, as well as initial exploration reconnaissance of the entire property area.

"We're trying to evaluate the property with many different techniques," Fingler said.

Pacific Ridge completed an airborne magnetometer survey of the property in April and field work for the 2011 program is expected to begin in early May, with the expansion of existing camp facilities to accommodate up to 25 exploration personnel.

The high resolution aeromagnetic survey, conducted by Precision GeoSurveys Inc. of Vancouver, B.C., used a helicopter-mounted cesium vapor magnetometer. A total of 900 line kilometers were flown along 100-meter-spaced lines and 1,000-meter-spaced tie lines.

"We call (these surveys) flying 'slow and low' to get a lot of detail of the underlying rock types, as well as structures, traps and other places where fluids may have collected," Fingler said.

Brock said aeromagnetic surveys have been shown to be useful in obtaining geophysical information at White Gold and Coffee, and Pacific Ridge hopes to locate and interpret fault structures that may underlie Skookum Jim and other anomalies on the Mariposa property using the technology.

Follow-up ground magnetic and electromagnetic surveying also will be conducted before the drill program gets underway in June in an attempt to detect distinct corridors of potential mineralization, Fingler said.

The phase 2 surveying will be conducted at greater detail than the aeromagnetic coverage and will provide optimum definition of targets for initial drill holes. Drilling is planned for mid-June, with lab results expected by August or September.

However, the geologist said she anticipates having some flexibility to react more quickly to the drill results with the help of preliminary trace element analysis provided by the team's two x-ray fluorescence, or XRF, units.

Work at other properties

Meanwhile, Pacific Ridge is making plans to follow up on earlier work at some of its other projects.

The 14-square-kilometer, or 5.4-square-mile, Goldcap claims that extend from the north-eastern boundary of Kinross' White Gold property and are located about 5 kilometers, or 3 miles, northeast of the Golden Saddle zone.

The 35-square-kilometer, or 13.5-square-mile, Polar/Stewart property lies at the eastern border of the Goldcap property and the northern border of ground held by Underworld. Brock said initial soil sampling on Polar/Stewart outlined gold values reaching 634 parts-per-billion gold that will be further detailed during 2011 to define targets for trenching and drilling.

Pacific Ridge's 27-square-kilometer, or 10.4-square-mile, Eureka Dome property, located about 55 kilometers, or 34 miles, north of the White Gold discovery, is now held under option by Golden Predator Corp., which planned a drill test of an extensive gold-in-soil anomaly previously defined by Strategic Metals on the west side of Eureka Dome.

With rising copper prices, Fyre Lake's 9 million-metric-ton copper-gold resource containing about 217 million pounds of copper is looking more promising.

Brock said he remembers staking the Fyre Lake claims in 1965 just before Christmas.

In the late 1990s, the company drilled 150 holes on the property and completed a preliminary scoping study when copper prices were around C$1/lb.

"If we can increase the resource, the project could become economic at today's prices," Brock said.

He estimated that another 100 million pounds of copper resource could boost the Fyre Lake's estimated mine life to about 10 years.

"We have plans to drill it in 2012," he added.