Millrock Receives Positive Initial Mineralogy Results From the Nikolai (Ni-Cu-Co-PGE) Project, Alaska

VANCOUVER, British Columbia, Sept. 29, 2022 (GLOBE NEWSWIRE) -- Millrock Resources Inc. (TSX-V: MRO) (“Millrock”) is pleased to report positive initial results from a mineralogical assessment of historical drill core from the Upper Eureka Zone (“UEZ”) and Core Eureka Zone (“CEZ”) at its 100% owned Nikolai Project, which hosts nickel (Ni) – copper (Cu) –cobalt (Co) – platinum group elements (PGE) prospects. The Nikolai Project is located within Alaska’s Delta Mining District, approximately 130 kilometers by road south of Delta Junction and approximately 280 kilometers southeast of Fairbanks. The Eureka zone consists of disseminated Ni-Cu-Co-PGE mineralization initially discovered by a subsidiary of INCO, and further expanded by Pure Nickel Inc., as reported in their press releases ranging between 2007-2014.

Highlights from the mineralogical assessment include:

  • 94% of the nickel within the CEZ is contained within nickel sulfide (pentlandite) and nickel alloy minerals.
  • 72% of the copper within the CEZ is contained within copper sulfides (chalcopyrite, bornite, chalcocite).
  • 80% of the nickel within the UEZ is contained within nickel sulfide (pentlandite) and nickel alloy minerals.
  • 75% of the copper within the UEZ is contained within copper sulfides (chalcopyrite, bornite, chalcocite).

Millrock President and CEO Gregory Beischer commented: “These are encouraging results! For large tonnage – low-grade deposits, it is crucial that potential recovery rates of the valuable metals are well understood. This first-pass work shows that much of the nickel and copper is in mineral form that allows strong recoveries with common processing methods.”

Methodology – Metal Content
Two composite samples from hole FL-003 were created for the UEZ and CEZ. Each composite was comprised of six quarter-core sample intervals spread across the mineralized zones. The anticipated metals content for each of the composited samples was calculated using historical assays from the work done by INCO in 1997 (Table 1). Historical logging and sampling of the INCO drill core was done under the direct supervision of Gregory Beischer, the qualified person responsible for the contents of this disclosure. Historical assays were performed at Chemex, Inc. in Reno, Nevada. Chemical analysis of the composites for this study were completed prior to the mineralogical study to validate the historical assay results completed by INCO (Table 1). Concentrations determined by INCO and by Millrock were found to be similar.

Table 1. Sample intervals, historical grades, calculated composite grades, and actual assay results from mineralogical study for selected samples from hole FL-003 to create composites for the CEZ and UEZ.

Composite 1 - Core Eureka Zone (CEZ)
Sample Hole ID From ft To ft Ni ppm Cu ppm Co ppm Pd ppb Pt ppb Au ppb
FX536263 FL-003 758 763 1900 1800 290 164 105 10
FX536264 FL-003 763 768 1900 1870 260 162 80 14
FX536270 FL-003 793 798 2500 1270 220 164 80 10
FX536274 FL-003 813 818 3000 1560 240 206 80 52
FX536277 FL-003 828 833 2300 820 180 118 50 16
FX536281 FL-003 848 853 3200 1460 210 132 50 24
CEZ Calculated Grade (Historic Assays) 0.25 0.14 0.02 0.157 0.072 0.023
New Assays Results from Composite Samples 0.25 0.16 0.02 0.173 0.043 0.068
Composite 2 - Upper Eureka Zone (UEZ)
Sample Hole ID From ft To ft Ni ppm Cu ppm Co ppm Pd ppb Pt ppb Au ppb
FX536768 FL-003 257 262 1690 385 141 82 42.5 2
FX536772 FL-003 283 288 1500 340 120 71 33 2
FX536084 FL-003 347 350 2397 938 146 128 55 14
FX536086 FL-003 400 405 2636 918 154 132 65 16
FX536798 FL-003 415 420 1975 630 133 83 36 12
FX536253 FL-003 708 713 2000 940 220 146 70 24
UEZ Calculated Grade (Historic Assays) 0.20 0.07 0.02 0.104 0.049 0.009
New Assays Results from Composite Samples 0.23 0.06 0.02 0.135 0.031 0.095

Methodology Mineralogical Study
The mineral processing work was completed by the Bureau Veritas Metallurgical Laboratory in Richmond, British Columbia, Canada. The individual composites were ground to ~125µm following standard grind calibration procedures. The ground composites were sized using wet screens and a cyclone sizer, and then sized into four fractions for chemical analysis and QEMSCAN analysis. QEMSCAN Particle Mineral Analysis was conducted on each size fraction of the sized composites to determine nickel and copper deportment and fragmentation characteristics.

Initial Mineralogical Study Results
Nickel sulfide and nickel alloys accounted for ~94% of the total nickel within the CEZ composite sample (only 5.1% of total nickel in silicates). Pentlandite was the principal nickel bearing sulfide and carried ~92% of the total nickel in the CEZ composite. Pentlandite content was measured at 0.68% by weight. The remaining potentially recoverable nickel was in the nickel alloys and nickel metal, which accounted for ~2% of the total nickel. Sulfur is higher in the CEZ (1.32%) and there is an increased amount of pyrrhotite (1.78% by weight). Interlocking between pentlandite and pyrrhotite was rarely observed, which will be favorable to the pentlandite separation from pyrrhotite.

Nickel sulfide and nickel alloys accounted for ~80% of the total nickel within the UEZ composite sample (18.9% of total nickel in silicates). Pentlandite was the principal nickel bearing sulfide and carried ~64% of the total nickel in the CEZ composite. Pentlandite content was measured at 0.44% by weight. The remaining potentially recoverable nickel was in the form of nickel alloy and nickel metal, which accounted for ~16% of the total nickel. Sulfur is lower in the UEZ (0.49%), likely due to the decrease in pyrrhotite. These results are summarized in Table 2 below.

Table 2. Summary of Ni-Fe-S deportment of Eureka Zone composites

Nickel Deportment CEZ UEZ
Ni-Fe Sulfides 92.2 % 64.1 %
Ni-Fe Alloys 2.1 % 16.7 %
Sulfide-Hydroxide 0.6 % 0.3 %
Silicates (Olivine) 5.1 % 18.9 %
Total Potential Recoverable Nickel 94.3 % 80.8 %
% Ni from chemical analysis 0.25 % 0.23 %
% S from chemical analysis 1.32 % 0.49 %
Weight % pentlandite 0.68 % 0.44 %
Weight % pyrrhotite 1.78 % 0.55 %

Copper sulfides accounted for ~71% to 75% of the total copper within the CEZ and UEZ composites. Chalcopyrite is the dominant copper sulfide and accounts for ~67% to 71% of the copper in the composite samples. Bornite, chalcocite, cuprite, malachite, and azurite were also present, in the composite samples. The remainder of the copper (~24% to 28%) was present in valleriite (Cu-Fe-Mg sulphate). The copper sulfide contents were 0.31% by weight in the CEZ and 0.14% by weight in the UEZ. These results are summarized in Table 3 below.

Table 3. Summary of Cu-Fe-S deportment of Eureka Zone composites

Copper Deportment CEZ UEZ
Chalcopyrite 66.8 % 70.7 %
Bornite 1.0 % 1.7 %
Chalcocite/Covellite 3.5 % 2.9 %
Cuprite, Malachite, Azurite 1.1 % 0.2 %
Valleriite 27.5 % 24.5 %
Total Potential Recoverable Copper 72.4 % 75.5 %
% Cu from chemical analysis 0.16 % 0.07 %
Weight % Cu Sulfides 0.31 % 0.14 %

An additional composite sample from the Lower Eureka Zone (“LEZ”) has been submitted to Bureau Veritas to complete identical mineralogical analysis. Assay results from the LEZ were reported in the Millrock press release from September 26, 2022 . The results of the third composite will be released when completed.

Quality Control – Quality Assurance
Millrock adheres to stringent Quality Assurance – Quality Control (“QA/QC”) standards. Core samples are kept in a secure location at all times. In this case, the samples were assayed at the Bureau Veritas laboratory in Vancouver, Canada. Preparation and analysis methods are described in further detail here . Analysis methods used include MA270 – 4-acid digestion ICP-ES/MS Finish and FA330 – Fire assay fusion Au, Pt, Pd by ICP-ES. The Qualified Person is of the opinion that the results reported in this press release are reliable.

Qualified Person
The technical information within this document has been reviewed and approved by Gregory A. Beischer, President, CEO, and a director of Millrock. Mr. Beischer is a Qualified Person as defined in NI 43-101.

About Millrock Resources Inc.
Millrock Resources Inc. is a premier project generator to the mining industry. Millrock identifies, packages, and operates large-scale projects for joint venture, thereby exposing its shareholders to the benefits of mineral discovery without the usual financial risk taken on by most exploration companies. The company is recognized as the premier generative explorer in Alaska, holds royalty interests in British Columbia, Canada, and Sonora State, Mexico, is a significant shareholder of junior explorer ArcWest Exploration Inc. and owns a large shareholding in Resolution Minerals Limited. Funding for drilling at Millrock’s exploration projects is primarily provided by its joint venture partners. Business partners of Millrock have included some of the leading names in the mining industry: EMX Royalty, Centerra Gold, First Quantum, Teck, Kinross, Vale, Inmet and, Altius as well as junior explorers Resolution, Riverside, PolarX, Felix Gold, and Tocvan.

ON BEHALF OF THE BOARD
“Gregory Beischer”
Gregory Beischer, President & CEO

FOR FURTHER INFORMATION, PLEASE CONTACT:
Melanee Henderson, Investor Relations
Toll-Free: 877-217-8978 | Local: 604-638-3164
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Some statements in this news release contain forward-looking information, including but not limited to execution of further deportment studies. These statements address future events and conditions and, as such, involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance, or achievements to be materially different from any future results, performance or achievements expressed or implied by the statements. Such factors include without limitation the completion of planned expenditures, the ability to complete exploration programs on schedule and the success of exploration programs.

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