Status: Available for Joint Venture
Target: The southwestern Alaska Peninsula is a classic island-arc environment located along the Pacific "Ring of Fire". This region is prospective for porphyry copper-gold-molybdenum systems and other intrusive-related deposits such as poly-metallic skarn and replacement deposits, base metal veins and epithermal gold deposits. Although all these styles of mineralization have been documented in this region, little modern exploration has been done and the region remains open for exciting new discoveries.
One such recent discovery is the Pyramid porphyry copper-molybdenum deposit, operated as a joint venture between Antofagasta (51%) and Full Metal Minerals (49%)and containing a reported historical resource of approximately 125 million tons of near-surface copper mineralization grading 0. 4% Cu and 0.025% Mo*. The deposit is a quartz diorite porphyry and hornfelsed sediment system hosting a reported historical copper-molybdenum resource. Highlights from recent Full Metal/Antofagasta drill programs include 156 m 0.97% Cu eq. and 310 m 0.53% Cu eq. (see Full Metal Minerals news release dated October 4, 2011 entitled "Full Metal and Antofagasta Minerals S.A. Significantly Expand Pyramid Porphyry Project, Alaska; Intercepts 155.9 meters Averaging 0.71% Cu, 0.018% Mo, 0.179 g/t Au or 0.97% Cu Equivalent").
*Source: Christie, J.S., 1975, Pyramid Project, Aleut-Quintana-Duval joint venture report on 1975 drill program: Quintana Minerals Report, 17 p. (Report held by the Aleut Corporation, Anchorage, Alaska.) The resource is for historical purposes only and not compliant with CIM definition standards for Mineral Resources and Mineral Reserves, as defined under NI 43-101. Though considered relevant by Millrock, these historical estimates are not considered reliable and should not be treated as current mineral resources or mineral reserves.
Property: The project area of interest (AOI) occurs on Bristol Bay Native Corporation (BBNC) lands beginning just north of Chignik Bay, one of the primary ports in the area, and extending to Stepovak Bay, near the southern end of the Peninsula (Figure 1). The AOI, as outlined in Figure1, covers approximately 680,650 ha.
Location and Setting: The project area is located in the southwestern portion of the Alaska Peninsula approximately 800 km (500 mi) southwest of Anchorage.
Previous Exploration: There have been several cycles of exploration on the Alaska Peninsula. Early exploration began around 1886, extended into the late 1920s and was primarily focused on the Shumagin, Popov and Unga Islands. Porphyry copper exploration began in the 1960s until the late 1970s and resulted in the discovery of promising prospects in the region including Bee Creek, Kawisgag, Mallard Duck Bay and Pyramid. In the late 1980s to early 1990s, gold exploration became popular in the region. The most recent exploration in the Chignik area was by Metallica Resources Inc. and Full Metal Minerals Ltd. in a joint venture that operated in 2005 and 2006. Overall, there has been very little exploration in this region due to the harsh climate and challenging topography. Modern exploration techniques and current commodity prices make exploration in this reason feasible with high potential for the discovery of anmetallic mineral deposits.
Geology and Mineralization: The geologic environment of the Alaska Peninsula is an island-arc volcanic setting, formed by the continued subduction of the Pacific plate underneath the North American plate. The region is primarily underlain by arc-related volcanic and plutonic rocks, and shallow marine and continental sedimentary rocks that range in age from late Paleozoic to Holocene in age (Figure 2). The AOI includes three existing porphyry copper prospects: Bee Creek, Kawisgag and Mallard Duck Bay.
The Bee Creek prospect is located in a northeast facing valley less than 5 kilometers from the north end of Chignik Bay. Mineralization at the Bee Creek prospect is hosted in hornfelsed sediments intruded by a multiphase dioritic intrusive and consists of both "A" (biot-qtz-py-cp) and "B" (qtz-py-mo) type veins and disseminated chalcopyrite, molybdenite and pyrite. A broad central potassic alteration zone (> 1 sq km) is exposed at surface, bordered by a discontinuous halo of phyllic alteration. Alteration and mineralization at Bee Creek has been dated at 3.6 ± 0.4 Ma (K/Ar dating). Surface soil sampling by Metallica-Full Metal Minerals in 2005-2006 revealed a 0.5% copper anomaly extending over a broad (>1 sq km) area and a more localized 0.05% Mo anomaly and discontinuous 0.5 ppm Au anomaly. Three IP lines and detailed ground magnetics were performed in 2005-2006 revealing a broad magnetic low under the surface geochemical anomaly and a donut-shaped IP anomaly at the north-end of the property.
Bear Creek Mining drilled five holes at Bee Creek in 1976. A report by Bear Creek indicated an intersection of 160 m averaging 0.25% Cu, 0.011% Mo and 0.062 ppm Au with 20 m of 0.35% Cu and 0.018% Mo open to depth (note this is a historic drill intersection that has not been verified by Millrock) In 2005, Metallica-Full Metal Minerals returned to the property, drilled 2 holes and encountered 118 m averaging 0.31% Cu, 0.009% Mo and 0.126 ppm Au with 20 m of 0.66% Cu and 0.255 ppm Au(see Full Metal Minerals news release dated October, 23, 2006 entitled "Full Metal and Metallica Encounter Copper Mineralization at Bee Creek").
Mineralization, alteration and anomalous copper values in soils and rocks extend over a broad area at the Bee Creek prospect (Figure 3) indicating the potential for a significant porphyry Cu-Mo-Au deposit near surface and potentially at depth. Although several holes have been drilled at the property, few of the geochemical or geophysical anomalies have been tested.
The Kawisgag prospect is located at the southern end of the BBNC AOI, 3 km to the northeast of the town of Ivanof Bay. There are two main centers of mineralization and alteration at the Kawisgag prospect and several other potassic alteration zones and geochemical anomalies nearby yet to be explored. Mineralization at Kawisgag has been dated at approximately 7 Ma (K/Ar) and consists of disseminated and vein chalcopyrite, molybdenite and pyrite. At least five types of quartz stockwork veins have been documented on the prospect from qtz-biot-py-cp "A"-type and qtz-mo-py "B"-type to qtz-py "D"-type with bleached selvages.
Most of the exploration to date has been in the northern cirque (Figure 4), where a multiphase diorite stock intrudes hornfelsed fine-grained sediments of the Eocene Tolstoi formation. Detailed mapping, surface rock geochemistry and ground geophysics in the northern cirque area have identified several targets for drill testing. The southern cirque contains an intrusive stock of similar composition but is completely unexplored. A rock grab sample collected in May 2012 returned results of 0.17% Cu and 0.131 ppm Au.
The Kawisgag prospect has several mineralization centers at surface spread over at least two cirque valleys and is completely untested at depth providing ample exploration opportunities. In addition to drill testing targets in the northern cirque, additional surface exploration work could be done including a soil survey and additional field mapping. A soil grab sample collected from the Kawisgag prospect in May 2012 returned encouraging results of 1.24 ppm Au, 123 ppm Cu and 79 ppm Mo.
Mallard Duck Bay
The Mallard Duck Bay prospect is a zone of hydrothermal alteration that covers an area greater than 8 sq km, located 5 km south of Chignik Lagoon. Limited exploration has been done at the Mallard Duck Bay prospect but mineralization appears to be associated with a dioritic stock and quartz diorite porphyry unit that intrude a sequence of volcanic host rocks. Alteration has been dated at approximately 21 Ma (K/Ar dating). An IP line and a ground magnetics line were run in 2005 and two strong chargeability anomalies were identified, one coincident with exposed mineralization in a potassic alteration zone.
The alteration zone at the Mallard Duck Bay prospect is extensive andvirtually unexplored, reflecting excellent exploration potential for the discovery of a porphyry copper-gold-molybdenum system (Figure 5).
Proposed Exploration: Recommended exploration programs for the Alaska Peninsula project includes additional geophysical and geochemical surveys at all three prospects with core drilling proposed for Bee Creek and Kawiskag.
Agreement and Terms: Millrock has entered into an exploration agreement with Bristol Bay Native Corporation (BBNC) granting exclusive rights to mineral exploration on BBNC subsurface mineral estate lands in the AOI outlined above.
Figure 1: BBNC Prospect Location Map (Enlarge)
Figure 2: BBNC Geology (Enlarge)
Figure 3: Bee Creek Image (Enlarge)
Figure 4: Kawisgag Image (Enlarge)
Figure 5: MDB Image (Enlarge)
"THE TECHNICAL INFORMATION WITHIN THIS DOCUMENT HAS BEEN REVIEWED AND APPROVED BY GREGORY A. BEISCHER, PRESIDENT & CEO OF MILLROCK RESOURCES INC. MR. BEISCHER IS A QUALIFIED PERSON AS DEFINED IN NI 43-101."
Related News Releases:
May 7, 2013
Millrock Makes Exploration Agreement with Bristol Bay Native Corporation, Alaska Peninsula, Alaska