The Goodpaster Project
Available for Option
The Goodpaster Mining District is a major focus area for Millrock. It has held claims in the area since 2015, but in 2019 made a major acquisition of mineral rights through claims staking. Millrock holds a database of approximately 20,000 surface samples and 11,434 m of NQ core drilling results acquired by previous operators over the Goodpaster Project area. Millrock’s proprietary database has allowed the company to efficiently acquire the most prospective grounds in the Goodpaster District.
Low angle and/or high angle vein-hosted and stockwork vein intrusion-hosted mesothermal gold systems related to mid-Cretaceous granitic to dioritic igneous activity. At the Pogo Gold Mine, now owned by Northern Star Resources (“Northern Star” ASX: NST) low-angle veins often manifest in stacked sets of two to four veins, each varying from 3 m to 20 m thick, and contain average grades of 13 grams per tonne gold. (See Cautionary Statement below). The Goodpaster Gold District consists of a Paleozoic, amphibolite grade, metamorphic basement intruded by a mid-Cretaceous granitic to dioritic batholith, and coeval stocks, dikes, and sills. Crustal scale faults, conjugate to the Denali and Tintina fault systems, bound the Goodpaster Gold District; the Shaw Creek sinistral fault forms the western edge and the Black Mountain sinisitral fault system marks the eastern edge of the Goodpaster crustal block.
The Pogo gold deposit, discovered in 1994-1996, is so far, the “crown jewel” of the Goodpaster Gold District, and the catalyst for the surge in district wide exploration in the late 1990’s to early 2000’s. Northern Star’s operating Pogo underground gold mine produces 300,000 ounces of gold annually, at an average historic grade of 13 grams per tonne, from a series of stacked, shallowly northwest dipping, quartz veins with free gold and minor pyrite and arsenopyrite. Current Pogo Mine resources and reserves stand at four million ounces of gold, with past production of four million ounces of gold. (Source: Northern Star website) Millrock cautions readers that this link is provided as a convenience and for information purposes only, and. Millrock makes no representation as to the accuracy, completeness or currency of the information appearing at the link or elsewhere on Northern Star’s website.
Location and Setting
The Goodpaster Project southwestern edge is 18 km north of the town of Delta Junction and 160 km southwest of Fairbanks, while its northeastern corner is 82 km from Delta Junction (Figure 1). The project lies in the Yukon-Tanana Uplands, characterized by spruce and birch covered rolling hills which grade into treeless alpine peaks in the northern and eastern project areas. The 80 km Pogo Mine road which passes through the western portion of the Goodpaster Project provides year-round access (Figure 2). Elevations on the project range from 300 m to 1600 m. Treeline is approximately 1000m in elevation.
The Goodpaster project consists of 1033 contiguous State of Alaska Mining Claims which cover 56,813 hectares, Millrock Resources owns all but 34 claims (1860 hectares) upon which Millrock has an option to purchase a 100% interest.
Geology and Mineralization
Gold mineralization defined in the Goodpaster Project area is hosted in quartz sulfide veins with associated silicate and carbonate alteration of the host rock. Gold vein occurrences define an approximately 50 km east-west trend along the south side of the Goodpaster Batholith granite (Pogo Trend on Figure 3 and Figure 4); gold vein occurrences also define an approximately 32 km northeast-southwest trend along the southeast side of the Shaw Creek fault (Shaw Creek Trend on Figure 3 and Figure 4) which intersects the Pogo Trend on the West Pogo Focus Area (Figure 3 and Figure 4). Variations in host rock and sulfide mineral content of the gold veins along these mineralized trends reflect the different settings at each prospect during the gold mineralizing event; age dating of mineralization and alteration products defines a window of gold emplacement between 104 and 95 million years before present. At this time during the mid-Cretaceous period, the Goodpaster district had just experienced a significant period of compression from a mountain building event which is proposed to have ended at 110 million years before present. During this mountain building event the metamorphic bedrock ruptured along zones of weaker rock (mafic lavas and graphitic sediments) producing a widespread flat lying reverse fault, now called the Pogo Shear. Extension and uplift, after 110 million years before present, produced brittle faults which acted as conduits for magma and the associated magmatic fluids during the 104-95 Ma time period; these magma’s and magmatic fluids are proposed as the source for the gold mineralization. When the extensional faults intersect the regional thrust, ascending magmatic fluids entered dilatation zones in the thrust and formed the low angle gold veins being mined at Pogo. In addition to the low angle gold veins, multiple high angle gold veins and the highly fractured, mineralized intersections of these high and low angle veins are mined at Pogo.
Throughout the Goodpaster Project area, arsenic and bismuth are the two metals most associated with gold bearing quartz veins – they are components of the minerals arsenopyrite and bismuthinite/bismuthotelurides which manifest as discrete grains adjacent to gold. Surface material samples (rock, soil, stream sediment) which contain elevated levels of gold arsenic and bismuth are the primary indication of subsurface gold mineralization. Millrock holds a database of approximately 20,000 surface samples and 11,434 m of NQ core drilling results, purchased from previous explorers, spanning the Goodpaster Project area. Millrock’s proprietary database has allowed the company to efficiently acquire the most prospective grounds in the Goodpaster District. High angle vein hosted gold mineralization displays discrete linear trends in surface sample plots, while low angle vein hosted and stockwork vein intrusion hosted gold mineralization display broad circular to ovoid trends in surface sample plots.
Geologically, Goodpaster District gold mineralization has thus far been associated with:
amphibolite grade metamorphic host rocks,
NE and NW oriented high angle faults,
NW plunging low-moderate angle faults, and
related to - or hosted in mid-Cretaceous granitic intrusions.
Geophysically, the gold bearing veins at Pogo exhibit:
a relative low resistivity response due to the dolomite-sericite alteration halo, and
a relative low magnetic susceptibility response also due to the alteration.
Using government mapping and airborne geophysical surveys, Goodpaster District mid-Cretaceous granitic intrusions can be identified, within the primarily metamorphic terrane, based on their:
relative low magnetic susceptibility,
radiometric survey response profile, and their
relative high resistivity (dependent on degree/style of alteration).
Proposed Exploration Program
C$6.65 million over 2-3 years
Millrock would conduct a systematic, multi-year, district wide, exploration program in the Goodpaster Project area as well as the greater Goodpaster District. The program would leverage Millrock’s proprietary database of surface samples and drill results purchased from previous operators. Desktop targeting studies are underway to “mine” the database and integrate geochemical results with project wide remote sensing data sets (color imagery, DEM, multispectral). Additionally, Millrock would commission a project wide geophysical data compilation, integration, and interpretation to assimilate the numerous public and private airborne and ground based survey datasets into the current exploration model. The targets and data gaps identified by desktop activities would be the focus of a multi-year surface sampling and mapping program to bring high confidence targets to drill readiness. Drill ready targets could then be drilled by the project partner or optioned out in focused areas to additional partners. Currently the West Pogo focus area is nearly drill ready; the proposed exploration program includes a ground based resistivity survey over the area adjacent to the Pogo Mine to image the possible low angle vein extension from the mine property, and then based on the results of that survey drill 5,000 m of core in 8-10 holes to test the multiple low angle stacked gold vein targets. The post drill refined West Pogo exploration model would then be applied to the remainder of the Goodpaster Project area.
The Company cautions that the mineralization at the Pogo mine is not necessarily indicative of the mineralization that may be identified on the Millrock properties, and there is no certainty that significant mineralization similar to that found at the Pogo mine will be identified on the properties.
1. West Pogo
Millrock’s West Pogo (17,591 hectare) claim block is adjacent to the Pogo Gold Mine. This is an underground mine operated and owned by Northern Star, which produces 300,000 ounces of gold annually. The mine road and power line cross the West Pogo claim block.
A new discovery reported by the prior owners of the Pogo Gold Mine (the Goodpaster prospect – see “GP” on Figure 3 and Figure 4) may trend onto Millrock’s West Pogo focus area. Approved permit applications filed by Northern Star indicate their plans to drill very close to the shared Pogo Mine / Millrock West Pogo claim boundary.
At the West Pogo focus area 221 claims were recently staked, adding on to the 141 claims Millrock previously held; the project now consists of 362 claims covering 17,591 hectares, of which Millrock Resources owns all but 34 claims (1860 hectares) which are under option to purchase a 100% interest. Previous explorers developed the Tourmaline Ridge (“TR”), Half-Ounce Gulch (“HOG”), and ER prospects. These three prospects along the west end of the Pogo Trend (Figure 3 and Figure 4) contain elevated gold, arsenic and bismuth surface soil and rock sample anomaly clusters related to northeast and northwest-trending high-angle faults (Figure 3). Previous core drilling campaigns targeted these elevated gold, arsenic, and bismuth surface sample anomalies and intercepted high angle quartz veins containing arsenopyrite with carbonate-sericite alteration halos. Assays of vein material returned elevated values of gold, arsenic, bismuth, silver, and antimony.
Low-angle structures and Cretaceous granitic-dioritic intrusions are mapped at West Pogo, and the prospects show strikingly similar geological and geochemical attributes to the nearby Pogo Gold Mine. Geophysical surveys and drilling will be needed to determine if the high-angle veins present on Millrock’s West Pogo focus area lead to thicker, shallow-dipping gold-bearing vein systems.
The Pogo Mine, Goodpaster prospect (see “GP” on Figure 3 and Figure 4) may trend onto Millrock’s West Pogo focus area. Approved permit applications filed by Northern Star indicate their plans to drill very close to the shared Pogo Mine / Millrock West Pogo claim boundary.
2. East Pogo
Millrock’s East Pogo (21,991 hectare) claim block is adjacent to the Pogo Gold Mine. This is an underground mine operated and owned by Northern Star, which produces 300,000 ounces of gold annually. At the East Pogo project 403 claims were staked over 30 km of the Pogo Trend of gold vein occurrences (Figure 3 and Figure 4). The claims cover several known prospects, Scott, Boundary, and Cal Surf. These prospect areas contain elevated gold, arsenic, and bismuth surface sample anomaly clusters related to northeast and northwest oriented high angle faults, Cretaceous granitic-dioritic intrusions and mapped low angle structures similar to Pogo style gold mineralization. Drilling conducted on the Boundary (“BD”) and Cal Surf (“CS”) prospects by previous operators intercepted auriferous quartz bismuthinite stockwork veins with carbonate-sericite alteration halos, and narrow auriferous quartz arsenopyrite veins with carbonate-sericite alteration halos respectively.
At the Shaw, Eagle, LMS trend 268 claims (17,231 hectares) were staked along 32 km of the Shaw Creek trend of gold vein occurrences (Figure 3 and Figure 4). These prospect areas contain elevated gold, arsenic, and bismuth surface sample anomaly clusters related to northeast and northwest oriented high angle faults, Cretaceous granitic-dioritic intrusions and mapped low angle structures. The claims cover the Eagle mid-Cretaceous granite hosted Intrusive Related Gold occurrence and surround the low angle thrust fault hosted LMS mesothermal gold resource held by Gold Reserve, Inc. (TSX:GRZ.V). Gold reserve reports an inferred gold resource of 267,000 ounces (Source: Technical Report on the LMS Gold Project, Goodpaster Mining District, Alaska February 19, 2016; Millrock cautions readers that this link is provided as a convenience and for information purposes only, and Millrock makes no representation as to the accuracy, completeness or currency of the information appearing at the link or elsewhere on Gold Reserve’s website). Drilling conducted on the Eagle prospect by previous operators intercepted granodiorite cut by gold bearing quartz albite calcite sulfide stockwork veins with sericite-chlorite alteration halos.
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.