Newcore Gold Announces 92.4% Gold Recoveries in Column Testwork for the Sewum and Boin Deposits at the Enchi Gold Project, Ghana
Newcore Gold Ltd. has reported favorable outcomes from metallurgical tests at its Enchi Gold Project in Ghana, achieving an average gold recovery of 92.4% from three column tests on samples from the Sewum and Boin deposits. The tests demonstrated a recovery range of 89.0% to 98.6%%. Notably, the study revealed low reagent consumption, with an average cyanide usage of 0.63 kg/t. Newcore is planning further metallurgical work, including tests on sulphide mineralization in 2023, which may refine processing strategies for heap leaching and optimize resource recovery.
- Average gold recovery of 92.4% from column tests.
- Low reagent consumption, with an average cyanide use of 0.63 kg/t.
- Results confirm the amenability of Enchi to heap leach gold recovery.
- None.
VANCOUVER, British Columbia, Oct. 12, 2022 (GLOBE NEWSWIRE) -- Newcore Gold Ltd. ("Newcore" or the "Company") (TSX-V: NCAU, OTCQX: NCAUF) is pleased to announce positive results from three additional column tests completed as part of the ongoing metallurgical program at the Company’s
Highlights from Column Test Results
- Three Column Tests Completed, Average Gold Recovery of
92.4% Achieved.- A total of three column tests (two from Sewum and one from Boin) returned an average gold recovery of
92.4% , with a recovery range of89.0% to98.6% .
- A total of three column tests (two from Sewum and one from Boin) returned an average gold recovery of
- Testwork Further Advances the Understanding of Processing Options for Enchi.
- Testing completed on representative samples from diamond drill core.
- Coarser samples used better represent modelled crush size for heap leach processing.
- Larger sized samples used in the columns with each sample weighing 30 kg.
- Low Reagent Consumption.
- Coarser grind size compared to prior testing contributed to lower consumption for cyanide as well as lower required amounts of lime and cement per kilogram.
- All samples showed modest cyanide consumption with an average of 0.63 kilograms per tonne ("kg/t"), with a 1.4 kg/t lime (hydrated) addition to maintain a pH above 10.5.
- Additional Metallurgical Testwork Planned.
- Optimization work to be completed on additional column tests.
- Further planned metallurgical work to consist of a bench-scale test to be completed in the field on the Project.
- Testing of sulphide mineralization to be completed in 2023.
Greg Smith, VP Exploration of Newcore stated, "This additional set of column tests completed on diamond drill core material from the Enchi Gold Project returned consistent results with high recoveries for all three composite samples, highlighting the amenability of Enchi to heap leach gold recovery. These samples are representative of the oxide and transitional material from the two largest deposits, Sewum and Boin, which together currently comprise approximately
Metallurgical Testing Summary
A total of three composite samples, two from Sewum and one from Boin, were submitted for column testwork to the Intertek Lab located in Tarkwa, Ghana, approximately four hours by paved road from the Enchi Gold Project. Material for the metallurgical samples consisted of half diamond drill core from holes drilled specifically to collect material for metallurgical sampling. The samples were selected to represent the two largest deposits on the Project, Sewum and Boin, and consisted of blended oxide and transitional material. For each deposit, individual samples included a range of gold grades and weathering intensities.
Composite KBDD077 was prepared using 15 samples from diamond drill hole KBDD077 drilled at Boin with a total weight of 41.6 kgs. Composite SWDD084A was prepared using 18 samples from diamond drill hole SWDD084 drilled at Sewum with a total weight of 42.5 kgs. SWDD084B was prepared using 16 samples from a second mineralized interval in diamond drill hole SWDD084 with a total weight of 38.6 kgs.
Recovery for the three samples averaged 92.4 %, with a range of
Table 1. Column Tests – Grade and Average Recovery
| Sample | Deposit | Grade Au g/t | Recovery Rate |
| Composite KBDD077 | Boin | 0.51 | |
| Composite SWDD084A | Sewum | 0.55 | |
| Composite SWDD084B | Sewum | 0.85 | |
| Average | 92.4% |
Composite samples were homogenized by mixing all material from the individual samples and crushed to
Screening and Grading Analysis of Head Samples
A size analysis was done on each of the three composite samples. The samples were tested at seven screen sizes and included analyses for percent mass. The samples were assayed for gold which showed that gold was present in all size fractions analysed. The distribution shows relatively consistent gold grades for all size fractions within a range of 0.41 grams per tonne gold ("g/t Au") to 1.46 g/t Au, with three outliers grading between 0.27 and 0.29 g/t Au. Results include
Table 2. Size Analysis by Composite Sample
| Sieve | Composite KBDD077 | Composite SWDD084A | Composite SWDD084B | |||
| % mass | Au g/t | % mass | Au g/t | % mass | Au g/t | |
| +2mm | 25.3 | 1.06 | 13.5 | 0.27 | 28.4 | 0.41 |
| +1mm | 9.6 | 1.13 | 13.7 | 0.64 | 13.3 | 0.42 |
| +250µm | 4.0 | 1.07 | 5.3 | 0.94 | 5.2 | 0.43 |
| +150µm | 3.6 | 0.49 | 4.4 | 0.84 | 4.1 | 0.66 |
| +106µm | 9.2 | 1.29 | 9.5 | 1.11 | 8.4 | 1.46 |
| +75µm | 13.7 | 0.29 | 12.9 | 0.44 | 9.6 | 0.92 |
| -75µm | 34.6 | 0.28 | 40.7 | 1.22 | 31.2 | 0.87 |
Head Sample Analysis
Using the results of the sizing and grading analysis, a head grade was calculated for each of the composite samples. The results were then compared to the head grade assays which were completed on the 50-gram subsamples. The results compared well for the three composites with each having an average grade representative of the average grade of the deposits.
Table 3. Grade Analysis by Composite Sample
| Gold Grade g/t | KBDD077 | SWDD084A | SWDD084B | Average |
| Assayed Grade | 0.51 | 0.55 | 0.85 | 0.64 |
| Calculated Grade | 0.69 | 0.87 | 0.70 | 0.75 |
| Average | 0.60 | 0.71 | 0.78 | 0.70 |
Five Day Coarse Bottle Roll Leach
Simulated heap leach testing was conducted on the composite samples using one-kilogram sub-samples which underwent leaching for five days. Batch dissolution tests (five days, intermittent rolling-bottle) was completed under excess leach conditions (
For composite KBDD077,
In all cases leaching continued after the first five days with ultimate recoveries expected to continue to increase with additional time.
Metallurgical Testing - Column Tests
Three 30 kgs closed-cycle column leach tests were conducted on the samples as received. The test charge was loaded into 150 mm in diameter by 1.5-metre-tall PVC columns. 30 kgs of the individual samples were agglomerated in a rolling drum using Portland cement at a 10 kg/t addition rate and then allowed to air dry for three days. After the samples had been air dried, they were loaded into the columns with the columns tilted at an angle to avoid stacking before being set upright. The column was then allowed to sit for a day before the initial level was taken to determine the slump.
The leaching parameters used in this column leach test included the addition of approximately 1.4 kg/t of lime which was blended into each feed solution and a cyanide concentration of 1,000 ppm. The initial feed solution was prepared by adding lime to tap water to obtain a solution pH above 10.5 followed by the addition of one gram of sodium cyanide per litre of solution with a solution application rate of 10L/h/m2 for all samples. The column testwork was conducted under a closed cycle for 90 days. All solution samples were assayed for gold and pH and free sodium cyanide was analyzed and recorded. Leach residue was thoroughly washed, dried, screened and analyzed for gold by fire assay.
A graph showing the leach curve can be viewed at the following link:
https://newcoregold.com/site/assets/files/5791/2022_10-ncau-nr-column-test-graph.pdf
The column tests are aimed at simulating the response to leaching of the sample with the emphasis on establishing the gold dissolution characteristics (rate and extent), reagent consumption, and the degree of slumping within the ore bed. All samples showed amenability to heap leaching, with recoveries averaging
The samples showed low cyanide consumption averaging 0.63 kg/t with a 1.4 kg/t lime (hydrated) addition to maintain a pH above 10.5. The slumps were within acceptable industry standards with an overall average of
Table 4. Summary of Column Leach Tests
| Composite | Leach Time | Slump % | Reagent Consumption kg/t | ||
| NaCN | Lime | Cement | |||
| KBDD077 | 90 days | 0.62 | 1.4 | 10 | |
| SWDD084A | 90 days | 0.65 | 1.4 | 10 | |
| SWDD084B | 90 days | 0.62 | 1.4 | 10 | |
| Average | 9.10% | 0.63 | 1.4 | 10 | |
The column leach test program has shown that the gold in the ore samples tested is readily leachable and amenable to heap leaching. The recoveries achieved are considered high and are interpreted to indicate the strong amenability to heap leaching. The particle size distribution and size by size analysis performed on both the head and residue after leach showed that the maximum gold recovery occurred in the finer fractions as compared to the coarser size fractions.
Screening and Grading Analysis of Tails Samples
A size analysis was done on all the tails from the composite sample column tests. The samples were tested at seven screen sizes including analyses for percent mass and assayed for gold. The distribution shows consistently low grades of gold for all size fractions within a range of 0.00 g/t Au to 0.80 g/t Au with two outliers of 1.11 and 1.42 g/t Au.
Table 5. Size Analysis of Tails by Composite Sample
| Sieve | Composite KBDD077 | Composite SWDD084A | Composite SWDD084B | |||
| % mass | Au g/t | % mass | Au g/t | % mass | Au g/t | |
| +2mm | 13.5 | 0.18 | 14.8 | 0.04 | 38.2 | 0.18 |
| +1mm | 13.7 | 0.14 | 8.0 | 0.30 | 9.6 | 0.17 |
| +250µm | 5.3 | 0.08 | 3.2 | 0.00 | 3.7 | 0.10 |
| +150µm | 4.4 | 0.05 | 3.2 | 0.09 | 2.8 | 0.58 |
| +106µm | 9.5 | 0.09 | 8.9 | 0.74 | 7.0 | 1.11 |
| +75µm | 12.9 | 0.04 | 22.1 | 0.80 | 9.0 | 1.42 |
| -75µm | 40.7 | 0.01 | 39.8 | 0.17 | 29.8 | 0.05 |
Enchi Gold Project Mineral Resource Estimate
The Enchi Gold Project hosts a pit constrained Inferred Mineral Resource of 70.4 million tonnes grading 0.62 g/t Au containing 1.41 million ounces gold (see Newcore news release dated June 8, 2021). Mineral resource estimation practices are in accordance with CIM Estimation of Mineral Resource and Mineral Reserve Best Practice Guidelines (November 29, 2019) and follow CIM Definition Standards for Mineral Resources and Mineral Reserves (May 10, 2014), that are incorporated by reference into National Instrument 43-101 ("NI 43-101"). The Mineral Resource Estimate was prepared by independent qualified person Todd McCracken, P. Geo. of BBA E&C Inc. The technical report, titled "Preliminary Economic Assessment for the Enchi Gold Project, Enchi, Ghana" has an effective date of June 8, 2021, and is available under the Company’s profile on SEDAR at www.sedar.com.
Enchi Drill Program
A 5,000 metre discovery and resource expansion drill program, following up on the success achieved to date from drilling at Enchi, commenced in Q3 2022. Diamond drilling will focus on continuing to define the higher-grade sulphide mineralization at depth with a goal of delineating the potential for high-grade underground resources at Enchi. Reverse Circulation ("RC") drilling will target near-surface oxide and shallow sulphide mineralization with a goal of outlining additional resource growth along strike and depth at all deposit areas. RC drilling will also be planned to follow-up on discoveries made as part of the recently completed 90,000 metre drill program. Additional exploration work is also on-going, including metallurgical testwork and trenching of high-priority surface anomalies.
A 90,000 metre discovery and resource expansion drill program (commenced in August 2020) was completed at Enchi in Q2 2022. The program included both RC and diamond drilling and included the first deeper drilling on the Project. Newcore’s multi-pronged exploration approach delivered on the goals set out at the start of drilling: (i) successfully outlined potential resource growth along strike at all four existing deposits (Sewum, Boin, Nyam, Kwakyekrom); (ii) encountered strong results at previously drilled zones that are outside of the resource area (Kojina Hill and Eradi); (iii) drilling intersected high-grade at depth which has outlined the potential for underground resources; and (iv) identified new discoveries from successful first pass drilling on early stage kilometre-scale gold-in-soil anomalous targets (Sewum South, Tokosea). The total planned drill program consisted of 575 holes representing 92,583 metres.
Newcore Gold Best Practice
Newcore is committed to best practice standards for all exploration, sampling and drilling activities. Drilling was completed by an independent drilling firm using industry standard RC and Diamond Drill equipment. Analytical quality assurance and quality control procedures include the systematic insertion of blanks, standards and duplicates into the sample strings. Samples are placed in sealed bags and shipped directly to Intertek Labs located in Tarkwa, Ghana for 50 gram gold fire assay.
Qualified Person
Mr. Gregory Smith, P. Geo, Vice President of Exploration at Newcore, is a Qualified Person as defined by NI 43-101, and has reviewed and approved the technical data and information contained in this news release. Mr. Smith has verified the technical and scientific data disclosed herein and has conducted appropriate verification on the underlying data including confirmation of the drillhole data files against the original drillhole logs and assay certificates.
About Newcore Gold Ltd.
Newcore Gold is advancing its Enchi Gold Project located in Ghana, Africa’s largest gold producer (1). The Project currently hosts an Inferred Mineral Resource of 1.41 million ounces of gold at 0.62 g/t (2). Newcore Gold offers investors a unique combination of top-tier leadership, who are aligned with shareholders through their
On Behalf of the Board of Directors of Newcore Gold Ltd.
Luke Alexander
President, CEO & Director
For further information, please contact:
Mal Karwowska | Vice President, Corporate Development and Investor Relations
+1 604 484 4399
info@newcoregold.com
www.newcoregold.com
(1) Source: Production volumes for 2021 as sourced from the World Gold Council
(2) Notes for Inferred Mineral Resource Estimate:
1. CIM definition standards were followed for the resource estimate.
2. The 2021 resource models used ordinary kriging (OK) grade estimation within a three-dimensional block model with mineralized zones defined by wireframed solids and constrained by pits shell for Sewum, Boin and Nyam. Kwakyekrom used Inverse Distance squared (ID2).
3. A base cut-off grade of 0.2 g/t Au was used with a capping of gold grades varied by deposit and zone.
4. A US
5. Metallurgical recoveries have been applied to four individual deposits and in each case three material types (oxide, transition, and fresh rock) with average recoveries of
6. A density of 2.20 g/cm3 for oxide, 2.45 g/cm3 for transition, and 2.70 g/cm3 for fresh rock was applied.
7. Optimization pit slope angles varied based on the rock types.
8. Mineral Resources that are not mineral reserves do not have economic viability. Numbers may not add due to rounding.
9. These numbers are from the technical report titled "Preliminary Economic Assessment for the Enchi Gold Project, Enchi, Ghana", with an effective date of June 8, 2021, prepared for Newcore Gold by BBA E&C Inc. in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects and is available under Newcore’s SEDAR profile at www.sedar.com.
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 release.
Cautionary Note Regarding Forward-Looking Statements
This news release includes statements that contain "forward-looking information" within the meaning of the applicable Canadian securities legislation ("forward-looking statements"). All statements, other than statements of historical fact, are forward-looking statements and are based on expectations, estimates and projections as at the date of this news release. Any statement that involves discussion with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions, future events or performance (often, but not always using phrases such as "plans", "expects", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates", or "believes" or variations (including negative variations) of such words and phrases, or state that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved) are not statements of historical fact and may be forward-looking statements. In this news release, forward-looking statements relate, among other things, to: statements about the estimation of mineral resources; results of our ongoing metallurgical testwork program; results of our drill campaign, magnitude or quality of mineral deposits; anticipated advancement of mineral properties or programs; and future exploration prospects.
These forward-looking statements, and any assumptions upon which they are based, are made in good faith and reflect our current judgment regarding the direction of our business. The assumptions underlying the forward-looking statements are based on information currently available to Newcore. Although the forward-looking statements contained in this news release are based upon what management of Newcore believes, or believed at the time, to be reasonable assumptions, Newcore cannot assure its shareholders that actual results will be consistent with such forward-looking statements, as there may be other factors that cause results not to be as anticipated, estimated or intended. Forward-looking information also involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievements expressed or implied by the forward-looking information. Such factors include, among others: risks related to the speculative nature of the Company’s business; the Company’s formative stage of development; the Company’s financial position; possible variations in mineralization, grade or recovery rates; actual results of current exploration activities; fluctuations in general macroeconomic conditions; fluctuations in securities markets; fluctuations in spot and forward prices of gold and other commodities; fluctuations in currency markets (such as the Canadian dollar to United States dollar exchange rate); change in national and local government, legislation, taxation, controls, regulations and political or economic developments; risks and hazards associated with the business of mineral exploration, development and mining (including environmental hazards, unusual or unexpected geological formations); the presence of laws and regulations that may impose restrictions on mining; employee relations; relationships with and claims by local communities; the speculative nature of mineral exploration and development (including the risks of obtaining necessary licenses, permits and approvals from government authorities); and title to properties.
Forward-looking statements contained herein are made as of the date of this news release and the Company disclaims any obligation to update any forward-looking statements, whether as a result of new information, future events or results, except as may be required by applicable securities laws. There can be no assurance that forward-looking information will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking information.
FAQ
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