West Pogo

Prospect, Active

Alternative names

ER

Commodities and mineralogy

Main commodities Ag; Au; Bi; Te
Ore minerals arsenopyrite; gold; pyrite; silver
Gangue minerals dolomite; quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale BD
Quadrangle map, 1:63,360-scale B-3
Latitude 64.4486
Longitude -145.0867
Nearby scientific data Find additional scientific data near this location
Location and accuracy The West Pogo prospect consists of 17 square kilometers of State of Alaska claims. The coordinates are at about the center of the claims, about 5.1 miles west-southwest of the junction of the Goodpaster River and Indian Creek. The prospect is about 0.3 mile southwest of the center of section 27, T. 5 S., R. 13 E., of the Fairbanks Meridian. The prospect adjoins the claims of the Rainbow prospect (BD054); the location is accurate within 500 feet.

Geologic setting

Geologic description

In 2008, the West Pogo prospect was being explored by International Tower Hill Mines, Inc. (ITH) (2008) after they acquired it from AngloGold Ashanti (USA) Exploration, Inc. The rocks in the area are similar to those at the Pogo Mine (BD033) about 5 miles to the east, where biotite-quartz feldspar orthogneiss is intruded by a 100 Ma diorite. The West Pogo prospect is marked by an east-trending gold anomaly in the soils, which parallels a prominent fault zone. ITH drilled one hole in 2008 near the western margin of the pluton. The hole missed its intended target and remained in the pluton for its entire length; the best interval in the hole was 2 meters that contained 0.3 gram of gold per ton. The geochemistry suggests that the best mineralization is west of the hole.
First Star Resources optioned the property in 2010 and collected several 6-meter-long chip samples across 40 meters of mineralized rubble crop. The samples contained 3.79 to 6.53 grams of gold per tonne and 0.73 to 13.05 grams of silver per tonne (First Star Resources Inc., 2010).
Prior to 2010, ITH collected samples at the surface, mapped the geology, and completed a geochemical soil survey. In 2010, ITH formed a new company, Corvus Gold Inc., to take over many of their properties including West Pogo. They optioned the prospect to First Star Resources who did a 3D Induced Polarization survey, mapped the geology, and sampled in 2011. First Star returned the property to Corvus in December, 2011 and Corvus optioned the property to Alix Resources Corp. in March, 2012 (Corvus Gold Inc., 2012a, 2012b).
The mineralization at the West Pogo prospect occurs mainly as quartz veins similar to those at the Pogo Mine (BD033) about 5 miles to the east (Corvus Gold Inc., 2012b). The work in 2011 identified a new area of mineralization a kilometer long along a regional east-trending structure at the margin of the Cretaceous stock. Samples of altered granite and quartz veins contained up to 118 grams of gold per tonne and elevated bismuth and tellurium.
In summer 2012, Alix executed a discovery-phase drill program consisting of two NQ core drill holes of cumulative total length of 610 meters (2,002 feet). The purpose was to test the subsurface expression of a surface rock and soil gold anomaly, and both holes encountered orthogneiss with sericite-altered, iron-stained zones of brecciation and veining with arsenopyrite +/- pyrite that appeared to increase with depth (Alix Resources Corp., 2012a).
The results for drill hole WP-12-01 are 0.67 gram of gold per tonne from 243.7 to 249.3 meters including a 2.4 meter interval containing 1.74 grams of gold per tonne. The results for drill hole WP-12-02 are 1.10 grams of gold per tonne from 74.5 to 77.7 meters. The gold intercepts lie within a 95 meter (311 feet) zone of dolomite-sericite alteration overprinted by iron oxides after sulfides. Gold occurs with quartz, surrounded by iron oxide alteration that occurs intermittently throughout the entire drillhole (Alix Resources Corp., 2012b).
Geologic map unit (-145.089055374834, 64.4482177277547)
Mineral deposit model Gold-quartz veins that contain bismuth and tellurium (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization 100 Ma based on the diorite pluton at the center of the prospect (Alix Resources Corp., 2012a).
Alteration of deposit Dolomite-sericite overprinted by iron oxides after sulfides (Alix Resources Corp., 2012a).

Production and reserves

Workings or exploration
Prior to 2010, International Tower Hill (ITH) collected samples at the surface, mapped the geology, and completed a geochemical soil survey. As of 2010, ITH formed a new company, Corvus Gold Inc., to take over many of their properties including West Pogo. They optioned the prospect to First Star Resources who did a 3D Induced Polarization survey, mapped the geology, and sampled in 2011. First Star returned the property to Corvus in December, 2011 and Corvus optioned the property to Alix Resources Corp. in March, 2012 (Corvus Gold Inc., 2012a, 2012b).
In summer 2012, Alix executed a discovery-phase drill program consisting of two NQ core drill holes of cumulative total length of 610 meters (2,002 feet). The purpose was to test the subsurface expression of a surface rock and soil gold anomaly, and both holes encountered metagranite with sericite-altered, iron-stained zones of brecciation and veining with arsenopyrite +/- pyrite that appeared to increase with depth (Alix Resources Corp., 2012a).
The results for drill hole WP-12-01 are 0.67 gram of gold per tonne from 243.7 to 249.3 meters including a 2.4 meter interval containing 1.74 grams of gold per tonne. The results for drill hole WP-12-02 are 1.10 grams of gold per tonne from 74.5 to 77.7 meters. The gold intercepts lie within a 95 meter (311 feet) zone of dolomite-sericite alteration overprinted by iron oxides after sulfides. Gold occurs with quartz, surrounded by iron oxide alteration that occurs intermittently throughout the entire drillhole (Alix Resources Corp., 2012b).
In October 2016, Millrock Resources Inc. announced that, through a series of purchase and option agreements and claim staking, it has assembled a 39,159-acre land position covering high-potential gold targets (ARDF numbers BD054, BD055, and BD060) in the Goodpaster Mining District near the Pogo gold mine (BD033). The claims cover soil geochemical anomalies, many of which are untested. On several sites there are intersections obtained through drilling by prior operators that are anomalous in gold. Millrock conducted core re-logging, surface geologic mapping, and soil and rock sampling in 2016; this work defined a northeast–southwest-trending corridor of anomalous gold values and several east–west-trending quartz vein systems as well as a small low-angle, northwest-dipping quartz vein with similar characteristics to the tabular bodies at Pogo (BD033). Millrock also collected short-wave infrared spectra from both core and surface samples (Athey and Werdon, 2017).
Indication of production None

References

References

International Tower Hill Mines, Ltd., 2008, West Pogo: http://www.ithmines.com/s/WestPogo.asp (as of March 4, 2008).
Reporters D.J. Grybeck (Contractor, USGS); V.C. Zinno (Alaska Earth Sciences, Inc.); M.B. Werdon (DGGS)
Last report date 8/26/2017