HIGHLIGHTS
Process Water Supply
Liberty Gold has retainedLoughlin Associates and LRE Water, both experienced water exploration and evaluation consultant groups in theGreat Basin , to design and execute a hydrological evaluation of potential water sources in the region.- Desktop studies have commenced and field work is anticipated to start in July.
- Water supply requirements for a future mining operation range from 1,000 to 1,200 acre feet per annum (“AFA”); or ~39 to 47 litres per second (“l/s”), with an upper limit of
1,500 AFA (59 l/s).
Potential Land Exchange
- A block of land surrounding the Goldstrike deposit has been included in a proposed land exchange between
The US Bureau of Land Management land exchange with theUtah School andInstitutional Trust Lands Administration . - The “Utah School and Institutional Trust Lands Exchange Act of 2023”, Senate Bill 1405, was presented to the
US Congress in May and is currently in the committee stage in both the House and theSenate . - The Company continues to monitor progress of this legislation through the approvals process.
Metallurgical Testwork
- Metallurgical studies at Goldstrike are testing the amenability of heap leaching the historically mined materials thus potentially providing an opportunity to process this early in a future heap leach mining operation, increasing mine life, and improving the project economics.
- Sonic drilling in the
Hamburg /Main/Hassayampa area generated four composites of previously leached oxide ore from the two historic leach pads (“Leach Pads”), two composites of pad backfill (material underlying the Leach Pads, filling previously mined open pits) and two composites of waste rock materials. - Metallurgical column leach testing was completed with key results including:
- Leach Pad Material
- Weighted average gold extraction1 from column leach tests:
- Leach Pad 1 (run-of-mine) 62.0%
- Leach Pad 2 (-4 inch crush/agglomerate) 39.5%
- Weighted average gold extraction1 from column leach tests:
- Backfill (material underlying the Leach Pads):
- Pad Backfill - High Grade 70.5%
- Pad Backfill - Low Grade 81.7%
- Waste Rock Material
- Main Dump 91.2%
- Hamburg North Dump 71.7%
- Leach Pad Material
- Historic production records2 report that ~7.25 million tonnes (“Mt”) of oxide gold ore at an average grade of ~1.2 grams per tonne gold (“g/t Au”) was leached on the two pads during prior mining operations (1988 to 1994). Based on historic recoveries this indicates that there may be up to 70,000 ounces of gold remaining in the now closed and remediated historic heaps. Test results herein indicate that a portion of this gold could be amenable to extraction using conventional heap leaching.
- Leach Pads 1 & 2 and the underlying backfill are located directly over the Main/Hassayampa/
Hamburg oxide gold resource and would need to be stripped in a potential future open pit mining operation to access the underlying oxide gold resource.
METALLURGICAL TEST RESULTS – PHASE 3A
Historic Leach Pad Material (Column Leach Test Results)
- Results of metallurgical column testing at Goldstrike on leach pad material (>0.20 g/t Au) produced a column leach weighted average gold extraction of 49.3%, at an average gold grade of 0.58 g/t Au.
- Gold extraction was rapid, with >80% of the leachable gold extracted within the first 10 days.
- Reagent consumptions were low at 0.33 kilogram/tonne (“kg/t”) CN & 0.50 kg/t lime.
- Cement consumption was high and averaged 5.5 kg/t.
- Mineralized material (>0.20 g/t Au) tested came from a total of 348 metres (“m”) of sonic drilling in 21 sonic drill holes from Leach Pads “1” & “2” (see Figures 1 & 2).
- Based on historic records, the heaps were not adequately leached due to poor irrigation practices.
- Pad 1 was a run-of-mine heap, whereas Pad 2 was a -4” crush/agglomerate heap.
- Significant gold grades encountered in the sonic drilling (see press release dated
August 9, 2022 ) suggest incomplete gold leaching occurred throughout the historic heaps and the results herein indicate that the residual gold remains readily soluble under heap leach conditions. - Sonic drilling on the historic leach pads provided sufficient drill hole assay coverage to allow the potential inclusion of this material in a future mineral resource estimate.
- Testing is underway to characterize historic Leach Pad material crushed and screened at +12.5 millimeters (“mm”). It is anticipated that the +12.5 mm material could be used for new pad overliner and gravel drains, adding early ounces to the production profile.
Figure 1: Location plan of
Click here for Figure 1: https://libertygold.ca/images/news/2023/June/LocationPlanOfSonicDrillholes01062023.pdf
Figure 2: Cross-section through Historic Leach Pads (A-A' from Figure 1)
Click here for Figure 2: https://libertygold.ca/images/news/2023/June/CrossSectionThroughHistoricLeachPads01062023.pdf
Backfill Material
- Results of Phase 3A metallurgical column testing at Goldstrike on pits backfill material, underlying the Leach Pads produced are shown in Table 1.
- Leach kinetics are similar to in-situ material tested.
Sonic Drill testing of the backfill material ranged from 5 to 26 meters below the historic pad and averaged 10 meters in thickness. Current drill density suggests that the oxide gold mineralization is widely distributed above resource cut-off grades.
Waste Rock Material
- Results of Phase 3A metallurgical column testing at Goldstrike on historic surficial waste rock from the Main and Hamburg North areas are shown in Table 1.
- Drill testing of this material indicates oxide gold mineralization is widely distributed above resource cut-off grades.
For a table of results of the Goldstrike Phase 3A variability composite test results, see Table 1 or click here:
https://libertygold.ca/images/news/2023/June/GoldstrikePhase3ACompositeTesting01062023.pdf
Table 1: Results, Goldstrike Phase 3A Historic Heap Composite Testing*
*Master Composites were classified as Low Grade (0.20 to 0.40 g/t Au) and High Grade (>0.40 g/t Au).
For a graph of results of the Goldstrike Phase 3A composite leach curves, see Figure 3 below or click here: https://libertygold.ca/images/news/2023/June/GoldstrikePhase3ALeachCurves01062023.pdf
Figure 3: Cumulative Leach Curves Confirm Rapid Leach Kinetics
METALLURGICAL TEST PROGRAM
The metallurgical evaluation of the Goldstrike oxide gold mineralization consists of multiple phases of testwork including:
- Variability composite column tests from PQ drill core:
- Phase 13 (20 composites):
- 85.9% weighted average gold extraction, ranging from 55.0 to 97.0%
- Phase 24 (29 composites):
- 84.2% weighted average gold extraction, ranging from 46.4 to 95.0%
- Phase 3A (8 composites)
- Results released herein.
- Phase 3C (22 composites)
- Taken from PQ drill core drilled in 2022, these composites are currently in preparation for column testing. Infill drill holes cover
Hamburg , Basin and Padre areas.
- Taken from PQ drill core drilled in 2022, these composites are currently in preparation for column testing. Infill drill holes cover
- Phase 13 (20 composites):
- Bulk Samples
- Phase 3B
- Comprising 11, 300-1,000 kilogram, bulk samples taken from outcropping oxide gold mineralisation is under leach in the lab with final results expected in early Q3.
- Phase 3B
Composites for all phases of test work were selected through consideration of alteration and gold grade and gold cyanide solubility to achieve a range of geo-metallurgical types. Composites were assembled in
All metallurgical work at Goldstrike has been supervised by Gary Simmons MMSA, formerly the Director of Metallurgy and Technology for Newmont Mining Corp.
Metallurgical test work to be completed by year end on Goldstrike is anticipated to exceed pre-feasibility requirements. It is anticipated that one further phase of testwork is required to meet feasibility standards on current resources. Results continue to support a technically simple, low initial capital, low operating cost, combination of crush/agglomeration and ROM heap leach processing routes for oxide mineralization.
QUALIFIED PERSON
ABOUT
For more information, visit libertygold.ca or contact:
Phone: 604-632-4677 or Toll Free 1-877-632-4677
info@libertygold.ca
QUALITY ASSURANCE – QUALITY CONTROL
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
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.
2 See the “Preliminary Economic Assessment and Independent Technical Report for the
3 see press release dated
4 see press release dated
Photos accompanying this announcement are available at
https://www.globenewswire.com/NewsRoom/AttachmentNg/793316d4-1728-4d9b-99bd-39ee4a2b1160
https://www.globenewswire.com/NewsRoom/AttachmentNg/0414af43-29c9-4fab-854f-a2802eec5860
https://www.globenewswire.com/NewsRoom/AttachmentNg/a01eeeae-829b-4a29-af13-c168c570232c
https://www.globenewswire.com/NewsRoom/AttachmentNg/473e1692-02f2-4f8a-ac61-e3f6431c08d7
Figure 1
Location plan of Sonic Drill holes on Historic Pads
Figure 2
Cross-section through Historic Leach Pads (A-A' from Figure 1)
Table 1
Results, Goldstrike Phase 3A Historic Heap Composite Testing*
Figure 3
Cumulative Leach Curves Confirm Rapid Leach Kinetics
2023 GlobeNewswire, Inc., source