HIGHLIGHTS
- Phase 4A column leach testing on the
Rangefront Zone included 24 variability composites from large-diameter (“PQ”) drill core representing the range of rock types and gold (“Au”) grades encountered in oxide mineralization. - Key results include:
- 86.9% “weighted average gold extraction”1 from column leach tests.
- Gold extractions ranging from 54.1% to 95.8%.
- >80% of leachable gold extracted within 10 days.
- These new metallurgical data were not included in the recent mineral resource update (the “Black Pine Resource”)2 and will be added to the next resource update expected in late 2023.
- These new column test results suggest an increase in recoverable gold in the
Rangefront Zone of approximately 4% in the upper plate sandstone unit (“Ppos”) and approximately 10% in the middle plate limestone unit (“Pola”) relative to the recovery models used in the Black Pine Resource. The Rangefront Zone mineralization comprises approximately 27% of the Black Pine Resource 2.- These new data are being used to develop metallurgical recovery equations to feed into an updated, deposit-wide gold recovery model for use in future resource, engineering, and economic modeling. Aggregate metallurgical data from all phases of testwork to date indicate a gold recovery percentage in the mid-70s at the average grade used in the Black Pine Resource.
- Aggregate test results across four phases of metallurgical study over four years, comprising testwork on 113 composites and six bulk samples, continue to support a technically simple, low initial capital, low operating cost, run-of-mine (“ROM”) heap leach processing route for Black Pine oxide mineralization.
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1 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 24 column tests is 76%.
2 See press release dated
BLACK PINE METALLURGICAL TEST WORK
- Bulk sample column test results
- Phase 1A3 (6 x 300 kilogram surface bulk samples):
- 78.9% weighted average gold extraction, ranging up to 92.8%
- Phase 1A3 (6 x 300 kilogram surface bulk samples):
- Variability composite column tests (113 composites from PQ drill core)
- Phase 1B4 (29 composites):
- 82.9% weighted average gold extraction, ranging up to 94.5%
- Phase 25 (45 composites):
- 80.8% weighted average gold extraction, ranging up to 94.8%
- Phase 36 (15 low-grade composites):
- 65.2% weighted average gold extraction ranging up to 80.3%
- Phase 4A (24 composites):
- 86.9% weighted average gold extraction, ranging up to 95.8%
- Phase 1B4 (29 composites):
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3 Previously referred to as “Phase 1” – see press release dated
4 Previously referred to as “Phase 2” – see press release dated
5 Previously referred to as “Phase 3” – see press release dated
6 Previously referred to as “Phase 4” – see press release dated
Results generated by the
The deposit-wide gold extraction is represented through the aggregate test data illustrated in Figure 1 below. This graphic illustrates the gold grade to gold extraction relationship for all column tests conducted to date at Black Pine and clearly demonstrates a) the improved metallurgical response from the
For a graph of results of the Liberty gold grade-gold extraction results for all column test work to date, see Figure 1 or click here:
https://libertygold.ca/images/news/2023/March/Figure1BlackPineGoldGradeGoldExtractionResults03222023.pdf
Figure 1: Black Pine Gold Grade-Gold Extraction Results
*Data from several columns of Transitional Material are included in the above graph.
Two additional phases of metallurgical testwork are currently in progress, comprising:
- Phase 4B:
Discovery Zone , E-Pit, A-Pit,F Zone ,Tallman Pit andM Zone – 25 composites. - Phase 4C:
C/D Pit – 12 composites.
Results from these two phases of testing will be completed in the second half of 2023.
Internal clay content and rock quality models indicate that a small portion of the Black Pine Resource may require in-pit or top-of heap blending, eliminating the need for a crush/agglomeration flowsheet component, and supporting simple ROM heap leaching at Black Pine.
Metallurgical test work completed on Black Pine to date equals or exceeds pre-feasibility requirements, with oxide ROM heap leach recoveries characterised currently by 16 different grade-recovery relationships. It is anticipated that one further phase of testwork beyond that currently in progress is required to meet feasibility standards on current resources.
All metallurgical work at Black Pine has been supervised by Gary Simmons MMSA, formerly the Director of Metallurgy and Technology for Newmont Mining Corp.
PHASE 4A TEST RESULTS
- The 24
Rangefront Zone column leach tests produced a weighted average 86.9% gold extraction at an average gold grade of 0.47 grams per tonne gold (“g/t Au”), with a range from 54.1% to 95.8% gold extraction (see Table 1 below). - Gold extraction was rapid, with >80% of the leachable gold extracted within the first 10 days of column leaching (see Figure 2 below).
- Percent gold extraction is well-correlated with head grade, with the highest-grade composites returning the higher extraction numbers (see Figure 1 above). Of the 24 column tests:
- 17 column tests were conducted on material below 0.5 g/t Au and returned weighted average 79.4% gold extraction.
- 7 column tests were conducted on material between 0.5 g/t Au and 1.0 g/t Au and returned weighted average 90.9% gold extraction.
- Gold extraction is relatively insensitive to particle size. Most composite extraction results can be projected to coarse particle sizes without significant loss of gold extraction. The relative percent gold extraction insensitivity to increasing particle size is shown in Table 2.
For a table of results of the Black Pine Phase 4A variability composite test results, see Table 1 or click here:
Table 1: Results, Black Pine Phase 4A Variability Composite Testing
Black Pine Phase 4A - Rangefront Variability Composite Testing | ||||||||||||||||
Phase 4A Rangefront Variability Composites | Fine Bottle Roll | Coarse Bottle Roll | Column Tests | |||||||||||||
Feed Target P80 (75µm) | Feed Target P80 (1,700µm) | |||||||||||||||
Direct Leach | CIL Leach | Direct Leach | CIL Leach | |||||||||||||
Composite ID | Rock Formation | Feed P80 (µm) | Calc Hd Au (ppm) | Gold Extracted (%) | Feed P80 (µm) | Calc Hd Au (ppm) | Gold Extracted (%) | Feed P80 (µm) | Calc Hd Au (ppm) | Gold Extracted (%) | Feed P80 (µm) | Calc Hd Au (ppm) | Gold Extracted (%) | Feed P80 (mm) | Calc Hd Au (ppm) | Gold Extracted (%) |
BP533-90 | RF-Pola | 54 | 0.260 | 82.7 | 54 | 0.264 | 95.8 | 1,460 | 0.246 | 85.0 | 1,260 | 0.252 | 91.7 | 24.2 | 0.239 | 90.8 |
BP533-91 | RF-Pola | 36 | 0.825 | 79.5 | 54 | 0.798 | 88.3 | 1,580 | 0.804 | 80.5 | 1,570 | 0.823 | 83.4 | 23.3 | 0.782 | 86.7 |
B511CA-92 | RF-Ppos | 71 | 0.379 | 75.2 | 69 | 0.368 | 82.6 | 1,430 | 0.370 | 70.0 | 1,350 | 0.390 | 71.8 | 11.3 | 0.368 | 80.4 |
B511CA-93 | RF-Ppos | 64 | 0.173 | 71.1 | 69 | 0.172 | 90.7 | 1,560 | 0.147 | 67.3 | 1,430 | 0.170 | 80.6 | 25.2 | 0.150 | 82.7 |
B511CA-94 | RF-Ppos | 72 | 0.142 | 69.7 | 70 | 0.236 | 93.2 | 1,450 | 0.202 | 74.8 | 1,600 | 0.140 | 75.0 | 24.0 | 0.137 | 79.6 |
B511CA-95 | RF-Pola | 84 | 0.223 | 78.0 | 77 | 0.146 | 85.6 | 1,520 | 0.183 | 75.4 | 1,460 | 0.217 | 88.0 | 24.3 | 0.209 | 88.5 |
B511CA-96 | RF-Pola | 87 | 1.360 | 86.8 | 84 | 1.250 | 93.7 | 1,370 | 1.238 | 89.9 | 1,400 | 1.292 | 91.3 | 24.7 | 1.322 | 92.4 |
B511CA-97 | RF-Pola | 182 | 1.673 | 87.7 | 112 | 1.802 | 95.1 | 1,300 | 1.768 | 92.5 | 1,490 | 1.729 | 93.9 | 22.4 | 1.966 | 95.8 |
B511CA-98 | RF-Pola | 35 | 0.994 | 84.4 | 88 | 0.930 | 91.3 | 1,450 | 1.054 | 86.4 | 1,390 | 1.012 | 87.1 | 25.0 | 0.938 | 88.7 |
B511CA-99 | RF-Pola | 190 | 0.270 | 73.7 | 150 | 0.251 | 83.3 | 2,190 | 0.268 | 72.8 | 2,100 | 0.266 | 78.9 | 28.8 | 0.352 | 84.1 |
BP541-100 | RF-Ppos | 65 | 0.274 | 73.0 | 53 | 0.265 | 82.6 | 1,490 | 0.298 | 73.2 | 1,570 | 0.278 | 72.3 | 27.8 | 0.261 | 78.5 |
BP541-101 | RF-Ppos | 64 | 0.502 | 79.3 | 64 | 0.504 | 86.5 | 1,320 | 0.522 | 77.4 | 1,590 | 0.491 | 77.8 | 10.9 | 0.459 | 81.3 |
BP541-102 | RF-Ppos | 73 | 0.169 | 81.7 | 69 | 0.165 | 91.5 | 1,720 | 0.142 | 83.8 | 1,320 | 0.158 | 85.4 | 22.2 | 0.148 | 91.2 |
BP541-103 | RF-Ppos | 79 | 0.230 | 80.4 | 75 | 0.247 | 87.9 | 1,430 | 0.239 | 86.6 | 1,340 | 0.230 | 81.7 | 25.3 | 0.239 | 89.1 |
BP541-104 | RF-Ppos | 83 | 0.246 | 67.5 | 67 | 0.230 | 75.7 | 1,390 | 0.264 | 74.6 | 1,410 | 0.223 | 67.7 | 24.3 | 0.214 | 70.6 |
BP541-105 | RF-Pola | 92 | 0.252 | 80.2 | 105 | 0.252 | 87.7 | 890 | 0.261 | 83.5 | 1,510 | 0.248 | 86.7 | 12.4 | 0.224 | 87.5 |
BP541-106 | RF-Pola | 64 | 0.568 | 80.3 | 42 | 0.592 | 89.0 | 1,270 | 0.620 | 84.5 | 1,360 | 0.573 | 84.5 | 13.7 | 0.597 | 88.6 |
BP541-107 | RF-Pola | 47 | 0.226 | 71.7 | 69 | 0.216 | 82.9 | 2,540 | 0.289 | 80.6 | 1,290 | 0.197 | 74.6 | 12.5 | 0.200 | 76.5 |
BP556-108 | RF-Ppos | 52 | 0.199 | 63.3 | 56 | 0.167 | 71.9 | 1,680 | 0.185 | 62.7 | 1,170 | 0.160 | 60.6 | 13.5 | 0.144 | 59.0 |
BP556-109 | RF-Pola | 62 | 0.310 | 61.0 | 65 | 0.317 | 71.9 | 1,500 | 0.340 | 60.3 | 1,520 | 0.296 | 56.1 | 24.6 | 0.281 | 54.1 |
BP556-110 | RF-Pola | 42 | 0.236 | 80.9 | 62 | 0.154 | 75.3 | 1,440 | 0.250 | 77.2 | 1,490 | 0.134 | 63.4 | 24.5 | 0.123 | 66.7 |
BP556-111 | RF-Pola | 81 | 1.025 | 84.5 | 68 | 1.028 | 89.2 | 1,350 | 1.073 | 84.4 | 1,320 | 1.035 | 84.6 | 24.6 | 0.948 | 86.6 |
BP556-112 | RF-Pola | 57 | 0.742 | 82.6 | 62 | 0.764 | 89.1 | 1,330 | 0.822 | 86.4 | 1,390 | 0.790 | 85.2 | 12.3 | 0.738 | 90.0 |
BP556-113 | RF-Pola | 66 | 0.263 | 80.6 | 57 | 0.256 | 82.8 | 1,440 | 0.278 | 78.8 | 1,400 | 0.257 | 80.9 | 24.1 | 0.234 | 81.6 |
For a graph of results of the Black Pine Phase 4A variability composite leach curves, see Figure 2 or click here:
https://libertygold.ca/images/news/2023/March/Figure2BlackPinePhase4AVariabilityCompositeLeachCurves03222023.pdf
Figure 2: Cumulative Leach Curves Confirm Rapid Leach Kinetics
For a table of results of the Black Pine Phase 4A variability composite gold extraction sensitivity to modelled crush size testing, see Table 2 or click here:
Table 2: Results, Black Pine Phase 4A Variability Composite Gold Sensitivity to Crush Size
Black Pine Phase 4A - Rangefront Variability Composite Gold Extraction Sensitivity to Modelled Crush Size | |||||||||||||||
KCA Sample No. | Comp ID | Rock Formation | Calc Hd Au (ppm) | ||||||||||||
75 µ | 1700 µ | P80 12.5 mm | P80 25 mm | P80 50 mm | P80 75 mm | P80 100 mm | P80 125 mm | P80 150 mm | P80 175 mm | P80 200 mm | P80 250 mm | ||||
95101 A | BP533-90 | RF-Pola | 0.252 | 95.1 | 92.5 | 90.8 | 90.2 | 89.6 | 89.3 | 89.1 | 88.9 | 88.7 | 88.6 | 88.5 | 88.3 |
95102 A | BP533-91 | RF-Pola | 0.806 | 87.0 | 86.0 | 85.4 | 85.2 | 84.9 | 84.8 | 84.7 | 84.7 | 84.6 | 84.5 | 84.5 | 84.4 |
95106 A | B511CA-95 | RF-Pola | 0.196 | 87.4 | 87.4 | 87.4 | 87.4 | 87.4 | 87.4 | 87.4 | 87.4 | 87.4 | 87.4 | 87.4 | 87.4 |
95107 A | B511CA-96 | RF-Pola | 1.292 | 93.1 | 92.4 | 91.9 | 91.8 | 91.6 | 91.5 | 91.5 | 91.4 | 91.4 | 91.3 | 91.3 | 91.2 |
95108 A | B511CA-97 | RF-Pola | 1.788 | 94.9 | 94.9 | 94.9 | 94.9 | 94.9 | 94.9 | 94.9 | 94.9 | 94.9 | 94.9 | 94.9 | 94.9 |
95109 A | B511CA-98 | RF-Pola | 0.986 | 90.4 | 88.9 | 88.0 | 87.7 | 87.4 | 87.2 | 87.1 | 87.0 | 86.9 | 86.9 | 86.8 | 86.7 |
95110 A | B511CA-99 | RF-Pola | 0.281 | 82.1 | 82.1 | 82.1 | 82.1 | 82.1 | 82.1 | 82.1 | 82.1 | 82.1 | 82.1 | 82.1 | 82.1 |
95114 B | BP541-103 | RF-Pola | 0.237 | 86.2 | 86.2 | 86.2 | 86.2 | 86.2 | 86.2 | 86.2 | 86.2 | 86.2 | 86.2 | 86.2 | 86.2 |
95115 B | BP541-104 | RF-Pola | 0.235 | 73.8 | 71.1 | 69.3 | 68.7 | 68.1 | 67.7 | 67.5 | 67.3 | 67.1 | 67.0 | 66.9 | 66.7 |
95116 A | BP541-105 | RF-Pola | 0.247 | 87.5 | 87.3 | 87.2 | 87.1 | 87.1 | 87.1 | 87.1 | 87.0 | 87.0 | 87.0 | 87.0 | 87.0 |
95117 A | BP541-106 | RF-Pola | 0.590 | 87.8 | 87.3 | 87.0 | 86.8 | 86.7 | 86.7 | 86.6 | 86.6 | 86.5 | 86.5 | 86.5 | 86.5 |
95118 A | BP541-107 | RF-Pola | 0.226 | 81.4 | 77.4 | 74.8 | 73.9 | 73.0 | 72.4 | 72.1 | 71.8 | 71.5 | 71.3 | 71.2 | 70.9 |
95120 A | BP556-109 | RF-Pola | 0.309 | 61.7 | 58.2 | 55.9 | 55.1 | 54.4 | 53.9 | 53.6 | 53.3 | 53.1 | 52.9 | 52.8 | 52.5 |
95121 A | BP556-110 | RF-Pola | 0.179 | 80.9 | 74.1 | 69.7 | 68.2 | 66.6 | 65.8 | 65.1 | 64.6 | 64.2 | 63.9 | 63.6 | 63.1 |
95122 A | BP556-111 | RF-Pola | 1.022 | 88.1 | 86.7 | 85.8 | 85.5 | 85.2 | 85.0 | 84.9 | 84.8 | 84.7 | 84.6 | 84.6 | 84.5 |
95123 A | BP556-112 | RF-Pola | 0.771 | 88.1 | 88.1 | 88.1 | 88.1 | 88.1 | 88.1 | 88.1 | 88.1 | 88.1 | 88.1 | 88.1 | 88.1 |
95124 A | BP556-113 | RF-Pola | 0.258 | 82.4 | 81.7 | 81.3 | 81.2 | 81.0 | 80.9 | 80.9 | 80.8 | 80.8 | 80.8 | 80.7 | 80.7 |
Weighted Average | 0.569 | 88.5 | 81.0 | 79.5 | 79.0 | 78.5 | 78.2 | 78.0 | 77.8 | 77.7 | 77.6 | 77.5 | 77.3 | ||
95103 A | B511CA-92 | RF-Ppos | 0.375 | 79.9 | 78.0 | 76.7 | 76.3 | 75.8 | 75.6 | 75.4 | 75.2 | 75.1 | 75.0 | 74.9 | 74.8 |
95104 A | B511CA-93 | RF-Ppos | 0.162 | 88.6 | 84.3 | 81.6 | 80.6 | 79.7 | 79.1 | 78.7 | 78.4 | 78.2 | 77.9 | 77.8 | 77.4 |
95105 A | B511CA-94 | RF-Ppos | 0.171 | 89.7 | 82.1 | 77.3 | 75.6 | 73.9 | 72.9 | 72.2 | 71.7 | 71.2 | 70.9 | 70.5 | 70.0 |
95111 A | BP541-100 | RF-Ppos | 0.275 | 79.9 | 77.6 | 76.2 | 75.7 | 75.2 | 74.9 | 74.7 | 74.5 | 74.4 | 74.3 | 74.2 | 74.0 |
95112 A | BP541-101 | RF-Ppos | 0.496 | 85.0 | 81.3 | 78.9 | 78.1 | 77.2 | 76.7 | 76.4 | 76.1 | 75.9 | 75.7 | 75.6 | 75.3 |
95113 A | BP541-102 | RF-Ppos | 0.156 | 89.6 | 89.4 | 89.2 | 89.2 | 89.1 | 89.1 | 89.1 | 89.1 | 89.1 | 89.1 | 89.1 | 89.0 |
95119 A | BP556-108 | RF-Ppos | 0.171 | 63.6 | 61.3 | 59.9 | 59.4 | 58.9 | 58.6 | 58.4 | 58.3 | 58.2 | 58.0 | 58.0 | 57.8 |
Weighted Average | 0.258 | 82.3 | 79.2 | 77.2 | 76.5 | 75.8 | 75.4 | 75.1 | 74.9 | 74.7 | 74.6 | 74.4 | 74.2 |
METALLURGICAL TEST PROGRAM
Samples for Phase 4A test work were obtained through drilling PQ core holes. Composites were selected through consideration of rock type, alteration and gold grade to achieve a wide range of geo-metallurgical types. Composites were assembled in
For a map showing locations of drill holes used for metallurgical testing, see Figure 3, below, or click here:
https://libertygold.ca/images/news/2023/March/Figure3BlackPineMetMap03222023.pdf
Figure 3: Location of Drillholes used for Black Pine Metallurgical Samples
Program details included:
- Coarse bottle roll tests (target of 80% passing 10 mesh or 1.7 millimeter (“mm”) particle size).
- Fine bottle roll tests (target of 80% passing 200 mesh or 75 micron particle size).
- The direct leach samples were rolled/agitated in bottles in a 1.0 grams per liter (“g/l”) dilute sodium cyanide (“NaCN”) solution for 72 hours (for 200 mesh) or 144 hours (for 10 mesh).
- The 200 mesh (75 microns) CIL samples were rolled/agitated in bottles for 72 hours in a 1.0 g/l dilute NaCN solution, containing 20 g/l of activated carbon.
- Composites were leached in 10.2 mm and 15.2 mm (four and six inch) diameter columns between 78 to 90 days. And were leached with low strength (0.50 g/l) NaCN solution.
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Drill composites were calculated using a cut-off of 0.10 g/t Au. Drill intersections are reported as drilled thicknesses. True widths of the mineralized intervals vary between 30% and 100% of the reported lengths due to varying drill hole orientations but are typically in the range of 50% to 90% of true width. Drill samples were assayed by ALS Limited in
All statements in this press release, other than statements of historical fact, are "forward-looking information" with respect to
Such forward-looking information, involves known and unknown risks, which may cause the actual results to be materially different from any future results expressed or implied by such forward-looking information, including, risks related to the interpretation of results and/or the reliance on technical information provided by third parties as related to the Company’s mineral property interests; changes in project parameters as plans continue to be refined; current economic conditions; future prices of commodities; possible variations in grade or recovery rates; the costs and timing of the development of new deposits; failure of equipment or processes to operate as anticipated; the failure of contracted parties to perform; the timing and success of exploration activities generally; the timing of the publication of any updated resources; delays in permitting; possible claims against the Company; labour disputes and other risks of the mining industry; delays in obtaining governmental approvals, financing or in the completion of exploration as well as those factors discussed in the Annual Information Form of the Company dated
Although
Note to United States Investors Concerning Estimates of Measured, Indicated and Inferred Resources
The information in this News Release, including any information incorporated by reference, and disclosure documents of
Without limiting the foregoing, these documents use the terms “measured resources”, “indicated resources”, “inferred resources” and “probable mineral reserves”. These terms are Canadian mining terms as defined in, and required to be disclosed in accordance with, NI 43-101, which references the guidelines set out in the
Figure 1
Black Pine Gold Grade-Gold Extraction Results
Figure 2
Cumulative Leach Curves Confirm Rapid Leach Kinetics
Figure 3
Location of Drillholes used for Black Pine Metallurgical Samples
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