Estelle
Status: Joint Venture
Estelle Photo Gallery
Target: The Estelle property hosts high-grade gold veins spanning most of its 20 km length and five km width. Gold mineralization at Estelle is associated with composite intrusive complexes of Cretaceous age (~65 Ma). The geologic environment is similar to that hosting many major copper-gold and gold porphyry systems found throughout the world and within Alaska. Barrick Gold Corporation and NovaGold's Donlin Creek gold and Anglo American and Northern Dynasty's Pebble copper-gold projects are three such deposits currently under development in Alaska. Specifically, the Estelle property is located in the Kahiltna Terrane which also hosts the Pebble copper-gold deposit and Kiska's Whistler copper-gold deposit. Observations to date suggest mineralization at the Estelle Property is most closely related to the Reduced Porphyry Copper Gold model of Rowins (2000) or the Intrusion-Related Gold Systems model of Hart (2005).
The style of mineralization at the property varies between prospects but is generally intrusive or hornfels hosted, occurring as disseminations, veins, quartz stockworks and hydrothermal breccias. These features, and extensive surface geochemical anomalies, indicate the potential for large, bulk minable, intrusive-related or porphyry style deposits.
Location and Setting: The Estelle gold project is located in the Yentna and McGrath Mining Districts about 170 km northwest of Anchorage in the South Central Alaska Range. Millrock Alaska LLC, a wholly owned subsidiary of Millrock Resources Inc., holds 392 contiguous State of Alaska mining claims in the district, covering 24,600 ha. Estelle is one large, contiguous claim group that is adjacent to Kennecott Corporation's recently announced Whistler copper-gold discovery. The terrain is mountainous and challenging for exploration, but development logistics for a large mine are excellent. Road, port and power are less than 80 kilometers away along a broad, U-shaped valley.
Agreement and Terms: Teck American Inc., a subsidiary of Teck Resources Limited ("Teck"), optioned the Estelle Property from Millrock Resources Inc. and Millrock Alaska LLC in May, 2010. The land package at the time consisted of 214 state mining claims covering 13,200 ha. Recent staking by Millrock in July 2010 has increased the landholding by 177 state claims, 91 of which fall within the area of interest (AOI) defined in the Millrock-Teck agreement.
The Millrock-Teck agreement states that Teck has the sole exclusive and irrevocable right and option to earn up to 65% interest in and to the claims by making certain payments to Millrock and incurring certain expenditures on or in respect to the exploration and development of the claims.
Mineral production from the majority of the claim group is also subject to private royalty interests for a total net smelter return of 3.00%.
Geology and Mineralization: The geologic environment of the Estelle property is similar to the geologic environment that hosts many major copper-gold and gold porphyry systems found throughout the world and, of particular relevance, within Alaska's productive Tintina Gold Belt where Donlin Creek (Barrick/NovaGold) gold and Pebble (Northern Dynasty/Anglo American) copper-gold projects are currently under development. Gold mineralization in the Rainy Pass district is associated with the Mount Estelle composite intrusive complex.
The Estelle property is centered on the Estelle Pluton which is part of a series of plutons intruded into a Jurassic to Cretaceous flysch sequence as well as a Devonian to Pennsylvanian allochthonous sequence. The series of plutons was continuously emplaced from Late Cretaceous to Early Tertiary, 83 to 53 Ma, and is associated with mineralization.
Gold mineralization on the Estelle property is widespread. Four areas: Oxide/Oxide North, Stoney, Shoeshine, and RPM, have been identified by Millrock through soil and rock geochemistry studies. Nearly all of the mineralization on the Estelle property is spatially associated with porphyrytic intrusions and occurs as disseminations of sulfides, sheeted veins, stockworks, veinlets and hydrothermal breccias. Though mineralization is generally restricted to the intrusive rocks, at RPM mineralization also occurs in the hornfels.
OXIDE RIDGE
In 2009 at Oxide Ridge, multiple zones of mineralization were located in bedrock. During 2010 chip sampling across one of the zones returned assay results averaging 1.0 g/t over 22.86 m. To date, 416 soil samples and 110 rock samples were collected in the Oxide area. Out of 416 soil samples 64 were > 0.200 ppm gold. 40 of the 110 rocks samples collected were > 0.200 ppm gold. Additionally, 183 rock chip samples were collected of which 54 were > 0.200 ppm gold. Oxide Ridge had 13 chip sample starting points with a total of 338 m sampled. All of the starting points were located on the northwest face of Oxide Ridge and traverse most of the face.
A two-dimensional IP survey was conducted at Oxide in September 2010. The survey was located in Sections 9-12 Township 22 North Range 20 West, and consisted of two 5 km lines. The purpose of the survey was to further delineate known and newly discovered mineralization. The survey resulted in the depiction of weakly chargeable zones on both lines. The location of these anomalies roughly corresponds with the location of mineralization at Oxide Ridge and Oxide North. The chargeability anomalies are also roughly congruous with petrophysical test results of mineralized samples conducted by Teck.
STONEY
At the property scale, mineralization in the Stoney area can be separated into six slightly discontinuous NE trending gold anomalies. The anomalies are all > 2.5 km in length with the longest > 8 km in length. The distance from the northernmost to southernmost anomalies is about 11 km. Anomalous gold values correlate well with elevated arsenic values. Arsenic values define a more continuous trend in both rocks and soils (majority of samples > 1000 ppm As). Copper is also well correlated to the gold anomaly, with the majority of samples > 500 ppm Cu and the highest > 5,000 ppm Cu, but it is more concentrated in the middle area of the six trends.
The Stoney vein is a large massive sulfide vein ~4 km long x ~60 m wide hosted in a granodiorite. The massive sulfide is found with quartz, tourmaline, pyrite, chalcopyrite, arsenopyrite, pyrrhotite veins. Structurally, the Stoney vein lies on a single, major north-south structure which extends for at least a mile along strike and dips steeply (80-85 degrees) to the east. It is thought that the major structure represents a long-lived fault zone which was active during and after vein formation (Radford, 1986).
Approximately 365 soil samples have been collected to date near Stoney of which 23 were > 0.200 ppm gold. 360 rock samples have been collected, of which 164 were > 0.200 ppm gold.
The elevated gold in soil values from the Portage Pass area are a significant highlight from the 2010 program. As the surface geochemistry is slightly more elevated in copper than in the Oxide area, this new region has been included with the Stoney area, despite being geographically closer to the Oxide Ridge prospect. Rock samples from the area suggest that gold is intrusion-hosted here.
SHOESHINE
Mineralization at Shoeshine is intrusion-hosted. It is a vein swarm that has been traced for a strike length of 1 km and through a vertical range of 200 m. The width of the swarm is 300 m with individual vein samples up to 20 cm thick containing over 200 g/t gold. The occurrence of variable intrusive compositions and textures, intermixed with veins in outcrop and talus, indicates a complex intrusive and mineralization history.
At the property scale, the area is defined by a 2 km x 1.5 km x 2 km anomalous gold halo that surrounds Mt. Estelle. The halo is due to a lack of samples in the higher elevations and steep outcrops around the peak. Arsenic values correlate well to gold in both rocks and soils. The majority of the samples run > 500 ppm As. Copper values are also elevated in the area with the majority of samples containing > 200 ppm Cu. Copper is well correlated to gold in rock samples but is slightly less anomalous in the soil samples. Lead and zinc are both less anomalous than gold but are still at elevated levels in the southwest corner of the area with the majority of the samples of lead > 50 ppm and zinc > 100 ppm in both the rocks and soils.
During the 2009 field season, a zone of porphyry-style gold mineralization, made up of stockwork veining, and pervasive alteration, was identified at Shoeshine. Chip sampling across the exposed portion of the zone averaged 1.2 g/t over 12.1 m. During the 2010 field season, approximately 145 soil samples were collected near Shoeshine, of which 10 were > 0.100 ppm gold. Of the 13 rock samples collected in 2010, 2 were > 0.200 ppm gold. At Shoeshine 43 chip samples were also collected with a total of 518 m (1,700 ft) sampled. Over 310 chip samples were collected and they include 94 samples > 0.200 ppm gold, 30 samples > 1 ppm gold, and 11 > 10 ppm gold. The southeast, northwest and north faces were sampled giving data for 3/4's of the distance around Shoeshine.
To date, Millrock has collected approximately 265 soil samples near Shoeshine of which 99 samples were > 0.200 ppm gold. 375 rock samples have been collected to date of which 225 were > 0.200 ppm gold.
RPM
The RPM area is a new mineralized gold zone discovered by Millrock during the 2010 reconnaissance program. The area is significant in that mineralization is hosted in both hornfels and intrusive rocks as opposed to being strictly intrusion hosted, as seen at Oxide Ridge, Stoney and Shoeshine.
The area is defined by a 3,500 m long, northwest trending gold anomaly defined by soils > 0.010 ppm Au (best soil is 6.54 ppm Au). Copper values are also elevated in the area with the majority of assays returning 200-500 ppm Cu. The copper values outline a broader, more dispersed anomaly than the gold anomaly. Arsenopyrite is elevated in the rock chips, but remains only weakly anomalous in the soil samples. Molybdenum levels are generally low in both the soils and the rocks (3-5 ppm), but in comparison to the claim group as a whole, the southern claim blocks have a slightly elevated molybdenum signature with numerous soils > 3 ppm Mo, compared to the northern claim blocks, where molybdenum is generally < 3 ppm in the soil samples.
To date, approximately 160 soil samples and 56 rock samples were collected with the majority sampling hornfels (8 soils and 3 rocks were in intrusive units). Of the 160 soil samples, 13 were > 0.200 ppm gold with the best assay being 6.54 ppm gold. Of the 56 rock samples, 14 were > 0.200 ppm gold.
Exploration Program: The 2011 exploration program at Estelle is scheduled to begin in June. Preparations are currently underway for a drilling program at the Oxide/Oxide North and the Shoeshine prospects. Geologic and structural mapping will be used to characterize regional and local relationships to alteration and mineralization. A geotechnical program will consist of soil and rock sample collection and analysis including whole rock geochemistry, U/Pb and 40Ar/39Ar geochronology, fluid inclusions analysis, and petrography. In addition, gold potential will be investigated in the proximal composite pluton and in the surrounding hornfels zones using reconnaissance soil and rock sampling.
Millrock President & CEO, Greg Beischer, CPG,
Collecting Geological Observations at Estelle, August 2008 (Enlarge)
Millrock Seasonal Field Technician and Mountaineer, Ryan Campbell,
Collecting Samples at Estelle, August 2008 (Enlarge)
At Oxide Ridge, sampling of talus fines that are representative of bedrock immediately uphill from the sample site has outlined a strong anomalous zone measuring 200 meters by 300 meters. The average of the 24 talus fines samples in this anomalous zone is 2.32 grams per ton gold. Several samples of altered porphyritic magmatic rocks with arsenopyrite bearing quartz stockworks assay in the 1.0 to 4.0 grams per ton gold range.
(Enlarge)
At Shoeshine, the anomalous zone is 900+ meters by 300 meters. The average of the 49 talus fines samples in this anomalous zone is 0.585 grams per ton gold. Numerous rock samples exhibiting porphyry style mineralization assay in the 1.0 to 5.0 grams per ton gold range. One sample of porphyry rock cut by sheeted quartz veinlets assayed 13.1 grams per ton gold and individual high grade quartz veins within the anomalous zone contain multi-ounce levels of gold.
(Enlarge)
The results of Millrock's recent exploration work on the Estelle property establish the potential for discovery of large scale gold deposits and warrant a 2009 drilling program to further substantiate Estelle as a highly prospective world-class gold target.
Estelle Figure 1: Schematic Cross Section (Enlarge)
Estelle Figure 2: Geology and Rock Sampling Schematic (Enlarge)
Estelle Figure 3: Quartz veins and arsenopyrite with high gold content (Enlarge)
Estelle Figure 4: Alteration and Mineralization at Estelle Property (Enlarge)
Estelle Figure 5:
South Stoney Vein oxidized sulfides and gold mineralization at the Stony Vein prospect (Enlarge)
Estelle Figure 6: Altered intrusive rocks at the Estelle project (Enlarge)
Estelle Figure 7: Rock sampling at the Shoeshine prospect (Enlarge)
Estelle Figure 8: Summer 2011 Drilling funded by Teck (Enlarge)
Estelle Figure 9: Summer 2011 Drilling funded by Teck (Enlarge)
Related News Releases:
December 8, 2011
Millrock Reports Additional Drill Results From Estelle Project, Alaska
November 9, 2011
Millrock Intersects Intrusion-Related Gold System at Estelle Project, Alaska
September 13, 2011
Millrock Provides Update of Exploration Activities and Results
August 2, 2011
Millrock Commences Drilling at Estelle Gold Property, Alaska
June 1, 2011
Millrock Provides Update on Estelle Gold Project, Alaska and Early Exercise of Warrants by Major Company Partner
February 14, 2011
Millrock Announces Partner Elects to Proceed with First Option at Estelle Project, Alaska, and Approval of US$3.4 Million 2011 Program and Budget
September 23, 2010
Millrock Samples 9.1 Grams Per Tonne Gold Over 27.4 Meters At Estelle Project, Alaska
May 12, 2010
Millrock Provides Corporate Update
May 4, 2010
Millrock Announces Financing and Agreement for Exploration of Estelle Gold Property in Alaska
December 3, 2009
Millrock Reports Chip Sampling Results from Estelle Project, Alaska
February 5, 2009
Millrock Announces Purchase of 100% Interest in Estelle Gold Claims, Alaska
November 13, 2008
Millrock Announces Positive Sampling at Estelle Gold Project, Alaska
April 21, 2008
Millrock Resources Inc. reports the issuance of 650,000 common shares of the Company to Talon Gold
April 9, 2008
Millrock Announces Acquisition of the South Estelle Gold Property in Alaska
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