US Copper Corp Announces Results from Moonlight Drilling

May 15, 2024 7:28 PM EDT | Source: US Copper Corp.

Toronto, Ontario--(Newsfile Corp. - May 15, 2024) - US Copper Corp (TSXV: USCU) (OTCQB: USCUF) (FSE: C730) ("US Copper" or the "Company") is pleased to announce results from the 15-hole shallow drill program last fall on its Moonlight deposit at the Moonlight-Superior Copper Project in North-East California.


  1. Mineralized drill hole intercepts were submitted for sequential copper assays, and acid soluble copper was identified in 14 of 15 holes, including one intercept of 205 feet ("ft") of 0.644% recoverable copper;
  2. Results confirmed a small oxide cap covers the large Moonlight sulfide deposit. This cap had been considered waste rock by previous operators;
  3. Soluble copper averaged 91% of total copper; and
  4. Acid soluble copper greater than 0.2% occurs over an area of 2,000 ft by 1500 ft to an average depth of greater than 150 ft.

These results are now being reviewed by an independent engineering firm to determine:

  1. Parameters for further metallurgical testing;
  2. A new resource calculation for the oxide mineralization at Moonlight; and
  3. The economic viability of an oxide mining operation combining both the Engels and Moonlight oxide caps.

Management Commentary

"Results from our exploration drill program at Moonlight confirm a near-surface copper oxide cap sits above the larger copper sulfide deposit below. These types of copper oxide deposits are found in the major copper mining districts of the world and can typically be economically extracted, usually through low-impact surface mining, and processed at lower cost than copper sulfide ores. Furthermore, acid leaching of oxide copper produces high grade copper cathodes, with grade A cathode typically selling for a premium," commented Stephen Dunn, President and CEO of US Copper.

"With the recent addition of copper to the U.S. critical minerals list, we look forward to conducting a preliminary economic assessment to evaluate the viability of a copper oxide mining operation at the past-producing Engels deposit, towards advancing a secure and responsible domestic supply of U.S. mined copper," concluded Mr. Dunn.

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Table 1: Summary of drill hole data

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(* Total leachable copper is the total of the sulfuric acid recovery and the cyanide recovery)


The Moonlight deposit is primarily a copper sulfide deposit hosted in the Lights Creek stock of Quartz Monzonite (QM) which had intruded Triassic - Jurassic metavolcanics. The resource consists of an earlier stage of mineralization with disseminated sulfide minerals in the QM and a later stage structurally controlled mineralization of tourmaline vein and breccia structures of multiple orientations that house sulfides. A small oxide cap, dominantly malachite with some chalcocite and native copper, covers the surface of the deposit. In the 1970s Placer-Amex had estimated a resource for the oxide cap at 12.2 million tons at 0.54% copper. This estimate is historical in nature though and cannot be relied on. With the recent drilling at Moonlight, a new resource estimate will now be calculated for the oxide cap to update the current moonlight resource.

The Moonlight sulfide deposit hosts a current National Instrument 43-101 ("NI 43-101") indicated resource of approximately 252 million tons (154 million tonnes) averaging 0.25% copper and 0.07 oz/silver per ton, and an inferred resource of 109 million tons (62 million tonnes) averaging 0.24% copper and 0.08 oz/silver per ton, both above a US$6.25 net smelter return cut-off. Contained indicated resources are 1.272 billion pounds of copper and 18 million ounces of silver, and inferred resources of 534 million pounds of copper and 9 million ounces of silver. The Moonlight sulfide deposit remains open to the south and at depth. This resource estimate is contained in the NI 43-101 Technical Report and Preliminary Economic Assessment ("PEA") for the Moonlight Deposit, Plumas County, California, by Tetra Tech, dated April 12, 2018, available on US Copper's website and on SEDAR.

US Copper had this PEA prepared on its Moonlight deposit in 2018 and it demonstrated positive economics at $3.15 per pound copper. It was also determined that providing higher grade ore from our Superior and/or Engels deposits into the Moonlight mine plan would substantially enhance the Project's economics by potentially increasing cash flows in the initial years of production. The recently completed drill program at Superior in 2021 and at Engels and Moonlight in 2023 were designed to better define any higher grade ore at these deposits for potential starter pits for the Moonlight plant. Ultimately, the updated Engels and Superior resources will be incorporated into a revised Moonlight PEA.

Technical Information and Quality Control & Quality Assurance

US Copper personnel regularly observe procedures including the boxing of core at the drill site. Core is then securely delivered to the core logging and storage facility in Crescent Mills CA (~10 miles from the drill sites). The core is logged, magnetically scanned, and photographed. Periodic samples are collected for specific gravity testing and petrographic analysis. The core is then sawn in half. One half is bagged with appropriate documentation and securely transported to the ALS lab in Reno, NV. To ensure that proper QAQC accompanies the analyses appropriate QAQC elements are included in each batch of samples. The QAQC elements consist of certified standards, duplicate analyses and certified coarse blanks or blank material that has been documented to be barren for gold and base metals.

Qualified Person

The scientific and technical content of this press release has been reviewed and approved by George Cole, M.Sc., Director of US Copper who is a "Qualified Person" as defined in NI 43-101 Standards of Disclosure for Mineral Projects. George Cole is a Registered Professional Geologist through AIPG (CPG-11687).

About US Copper Corp

US Copper controls approximately 13 square miles of patented and unpatented federal mining claims in the Light's Creek Copper District in Plumas County, NE California; essentially, the entire District. The District contains substantial copper (silver) sulfide and copper oxide resources in three deposits - Moonlight, Superior and Engels, as well as several partially tested and untested exploration targets.

The Superior and Engels Mines operated from about 1915-1930 producing over 161 million pounds of copper from over 4 million tons of rock containing 2.2% copper with silver and gold credits.

The Moonlight Deposit was discovered and drilled by Placer Amex during the 1960's. Details of the resources on US Copper's property and the parameters used to calculate them can be found in the "Technical Report and Preliminary Economic Assessment for the Moonlight Deposit, Moonlight-Superior Copper Project, California, USA" dated April 12, 2018, on both the company's website at or on under the US Copper Corp profile.

The Moonlight PEA, prepared by Tetra Tech Inc., had the following highlights:

  • After-tax NPV of US$179M at an 8% discount rate and a $3.15 copper price.
  • After tax IRR of 14.6%
  • Initial Capital Cost: US$513M, including a contingency provision in the amount of US$71M
  • Plant Processing Rate: 60,000 tons per day (STPD)
  • Average Copper Recovery: 86.0%
  • Mine Life: 17 years, based on the existing Mineral Resource estimate
  • Life of mine copper production of 1.5 billion pounds

The Superior deposit is not included in the Moonlight PEA and it hosts a current NI 43-101 inferred mineral resource of 57 million metric tonnes at an average copper grade of 0.41%. Note no silver or gold were included as part of this resource.

Please note the PEA is preliminary in nature and includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves. Furthermore, there is no certainty that the preliminary economic assessment will be realized. Mineral resources that are not mineral reserves do not have demonstrated economic viability. Readers are encouraged to read the technical report.

For Further Information Contact:
Mr. Stephen Dunn, President, CEO and Director, US Copper Corp (416) 361-2827 or email

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this press release.

This press release contains forward-looking statements within the meaning of applicable Canadian and U.S. securities laws and regulations, including statements regarding the future activities of the Company. Forward-looking statements reflect the current beliefs and expectations of management and are identified by the use of words including "will", "hopes", "anticipates", "expected to", "plans", "planned", "intends" and other similar words. Actual results may differ significantly. The achievement of the results expressed in forward-looking statements is subject to a number of risks, including those described in the Company's management discussion and analysis as filed with the Canadian securities regulatory authorities which are available at Investors are cautioned not to place undue reliance upon forward-looking statements.

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