High and Rapid Gold Extraction, Combined with Relative Insensitivity to Crush Size Support Run-of-Mine Heap Leach Processing

VANCOUVER, B.C. – Liberty Gold Corp. (LGD-TSX; OTCQX: LGDTF) (“Liberty Gold” or the “Company”) is pleased to report results from Phase 3 variability composite metallurgical column testing from large-diameter (“PQ”) drill core at its Black Pine Oxide Gold Project in southeastern Idaho (“Black Pine”). The objective of the Phase 3 metallurgical program was to expand the geographical and ore type distribution of Phase 1 and Phase 2 column testing which included six surface bulk samples and 29 variability composites.

Highlights

Phase 3 testing included 45 new variability composites testing the full range of rock types, gold (“Au”) grades and ore types encountered across Black Pine.
Aggregate results support a simple, low capital, low operating cost, Run-of-Mine (“ROM”) heap leach processing route for Black Pine ores.
Gold extractions are consistent with previous metallurgical programs, with >80% of the leachable gold extracted within 10 days and final column leach gold extractions ranging up to 94.8%:
Phase 1 bulk sample column test results: 78.9% weighted average gold extraction, ranging up to 92.8%1
Phase 2 variability composite column tests: 82.1% weighted average gold extraction, ranging up to 94.5%1
Historical column tests from bulk samples and drill core composites: 80.8% weighted average gold extraction.
[1] See press releases dated August 18, 2020 and June 16, 2020

Gary Simmons, independent consulting metallurgist to Liberty Gold commented: “Data from metallurgical testing to date at Black Pine continues to indicate rapid leaching and relatively high gold extractions from these gold oxide ores, with a consistent insensitivity to particle size and a predictable grade-recovery relationship. In Phase 3 a wider range of material types were tested and 38 of 39 tested composites passed load permeability testing at 100-metre heap height. Internal development of clay and rock models indicate that a smaller portion of the resource may require in-pit or top-of heap blending, eliminating the need for a Crush/Agglomeration flowsheet component, and supporting simple Run-of-Mine leaching at Black Pine.”

All metallurgical work at Black Pine has been supervised by Gary Simmons, formerly the Director of Metallurgy and Technology for Newmont Mining Corp. Mr. Simmons has managed or supervised a significant number of metallurgical testing programs on similar Carlin-style sedimentary-hosted oxide gold deposits.

Jon Gilligan, Chief Operating Officer for Liberty Gold said: “The consistent nature of the metallurgical results to date at Black Pine is very encouraging and points to a simple ROM operation. We are progressing the next phases of test work to confirm gold recoveries at lower operating cut-off grades and to expand our sampling coverage into the new Rangefront D-4 discovery area. These will provide us with an extensive metallurgical database across the deposit, which could support a feasibility-level evaluation at Black Pine.”

Key Points:

Forty-five column leach tests produced a weighted average* 80.8% gold extraction, with a range from 44.5% to 94.8% gold extraction. See Table 1, below, or click here: https://libertygold.ca/images/news/2021/October/Gold_Extraction_Data.pdf
Gold extraction was rapid, with >80% of the leachable gold extracted within the first 10 days of column leaching. See Figure 1, below or click here: https://libertygold.ca/images/news/2021/October/Cumulative_Leach_Curves.pdf
Percent gold extraction is well-correlated with head grade, with the highest-grade composites returning the higher extraction numbers. Of the 45 column tests:
18 column tests were conducted on material below 0.5 grams per tonne (“g/t”) Au, and returned weighted average 71.8% gold extraction
10 column tests were conducted on material between 0.5 g/t Au and 1.0 g/t Au and returned weighted average 79.0% gold extraction
17 column tests were conducted on material above 1.0 g/t Au, and returned weighted average 82.3% gold extraction
For further details see the grade recovery curve in Figure 2 or click here: https://libertygold.ca/images/news/2021/October/Grade_Recovery_Curve.pdf
Phase 4 metallurgical test work has commenced on 15 PQ drill core composite samples of lower-grade Black Pine mineralization, in the range 0.10 g/t Au to 0.20 g/t Au. Further PQ core drilling has commenced in support of a Phase 5 metallurgical program, considered at this time to be sufficient to support a future feasibility study at Black Pine, targeting the recent Rangefront D-4 discovery, Discovery Zone, F Zone, CD Extension and E Zone.
*Weighted average gold extraction is obtained using the following equation: (composite head grade (grams/tonnes) multiplied by extraction (%) for all head grades)/sum of all head grades. Using arithmetic averages tends to over-represent low grade composites and under-represent high grade composites. The arithmetic extraction average of the 45 column tests is 76%.

Table 1: Results, Liberty Gold Phase 3 Variability Composite Testing

see & read more on https://libertygold.ca/news/news/18-2021-news/388-liberty-gold-reports-weighted-average-80-8-gold-extraction-in-phase-3-metallurgical-column-testing-black-pine-oxide-gold-deposit,-idaho.html