Highlights from the metallurgical testing include:
- High average gold recoveries of 96.1%
- Sulphide ore is free milling (non refractory)
- Current processing plant design (gravity + CIL) is well sized to treat additional sulphide ore
“From our ongoing drilling programme results, we are confident that we have a sizeable sulphide resource sitting below the oxides at our
We could not be happier with the initial results from the comprehensive testwork programme, which shows that not only is the gold free milling, but that it displays optimal recovery through the existing gravity + CIL circuit already designed for the
We are confident that some of our existing 345,000oz of sulphides as per our latest resource statement will fall within our open-pittable reserves and therefore be added to the overall reserve number as we seek to update the technical report from our additional oxide drilling results and sulphide testwork.”
Comprehensive metallurgical testing programme was conducted by Maelgwyn South Africa (MSA) on composite samples from all defined mineral zones (north, south, and central domains) of the main shear zone.
The sulphide ore testwork programme involved the following:
- Head grade assays (
Multi Au x 3; Sg; As, Hg, S-package; Full ICP scan) - Diagnostic leach
- Comminution testwork - to be performed after a review of the gold recovery results.
- Gravity recovery followed by intensive cyanidation on the gravity concentrate.
- Cyanidation on the gravity middlings and tailings which involved leach rate tests to determine the effect of time on gold dissolution.
Intensive cyanidation on gravity concentrate
The ILR tests indicate that a gold dissolution of 96.37% over 6 hours is achieved and this is consistent with what was obtained for saprolite and laterite. The current gravity recovery equipment selection is adequately sized to recover gravity gold from the sulphides.
Leach Time | NaCN | Recovery | pH | Sample | Leached | Dissolved Oxygen Measured |
Au | Au | Au | DO | |||
Ppm | % | mg | mg | mg/L | ||
0 hrs | 20,000 | 0 | 11.64 | 0 | 0 | 15.93 |
1 hrs | 20,000 | 79.61 | 11.31 | 0.656 | 0.656 | 30.18 |
2 hrs | 20,000 | 91.48 | 11.16 | 0.753 | 0.098 | 22.49 |
4 hrs | 20,000 | 95.95 | 10.74 | 0.79 | 0.037 | 26.15 |
6 hrs | 20,000 | 96.37 | 10.47 | 0.794 | 0.003 | 21.71 |
7 hrs | 20,000 | 96.37 | 10.66 | 0.794 | 0 | 26.69 |
24 hrs | 20,000 | 96.37 | 10.6 | 0.794 | 0 |
Figure 1: Intensive cyanidation results
Leach results on middlings and tailings
Time | Reagent Addition | Head | Residue | Carbon | Reagent Consumption | Dissolution (Calc) | Account | |||
NaCN | CaO | Assayed | Calc. | Au | Au | NaCN | Sol + Carbon | Solid | Au | |
g/t | Kg/t | Au (g/t) | Au (g/t) | g/t | g/t | Kg/t | Au % | Au % | % | |
2 hrs | 5,000 | 0.24 | 0.30 | 0.31 | 0.25 | 2 | 0.94 | 20.48 | 20.48 | 104.80 |
4 hrs | 0.24 | 0.30 | 0.29 | 0.14 | 5 | 0.94 | 51.05 | 51.05 | 95.33 | |
6 hrs | 0.24 | 0.30 | 0.31 | 0.02 | 10 | 1.99 | 93.52 | 93.52 | 102.93 | |
8 hrs | 0.24 | 0.30 | 0.33 | 0.02 | 11 | 1.84 | 93.92 | 93.92 | 109.73 | |
12 hrs | 0.24 | 0.30 | 0.33 | 0.02 | 11 | 2.13 | 93.92 | 93.92 | 109.73 | |
16 hrs | 0.24 | 0.30 | 0.30 | 0.02 | 10 | 2.54 | 93.38 | 93.38 | 100.67 | |
18 hrs | 0.24 | 0.30 | 0.31 | 0.02 | 10 | 2.43 | 93.61 | 93.61 | 104.29 | |
24 hrs | 0.24 | 0.30 | 0.31 | 0.02 | 10 | 2.38 | 93.55 | 93.55 | 103.39 | |
36 hrs | 0.24 | 0.30 | 0.32 | 0.02 | 11 | 2.42 | 93.66 | 93.66 | 105.20 | |
48 hrs | 0.24 | 0.30 | 0.32 | 0.02 | 11 | 2.59 | 93.66 | 93.66 | 105.20 |
Figure 2: Leach test rate
The following is noted regarding the results:
- Rate of gold dissolution is high and the rate curve “plateaued” after 8 hours. An optimum residence time of 24 hours can be selected. Current leach design residence time of 24 hours will be more than adequate when treating sulphides.
- Lime requirements are low at 0.24kg/t- this is line with expectations as sulphides generally contain carbonates which will result in low lime demand.
- Cyanide optimization tests will be conducted to determine cyanide consumptions for design and operating cost estimates.
Ongoing comprehensive testwork will include additional comminution testing to determine optimal grind size, leach optimisation and further variability testing.
TSXV Final Approval
The Company is also please to announced that it has receive final approval from the
About
Qualified Person
The scientific and technical information contained in this press release has been reviewed, prepared and approved by Dr.
For more information:
President and Chief Executive Officer
+(27) 76 411 3803
Danny.Callow@africangoldgroup.com
Non-Executive Chairman of the Board
(604) 722-5381
Scott.Eldridge@africangoldgroup.com
Daniyal Baizak
VP Corporate Development
(416) 861-2267
Daniyal.Baizak@africangoldgroup.com
Camarco (Financial PR)
+44 (0) 20 3757 4997
AfricanGoldGroup@camarco.co.uk
Cautionary statements
This press release contains “forward‑looking information” within the meaning of applicable Canadian securities legislation. Forward‑looking information includes, but is not limited to, statements regarding, gold recoveries from the
This news release does not constitute an offer to sell or a solicitation of an offer to buy any of the securities in the United States. The securities have not been and will not be registered under the United States Securities Act of 1933, as amended (the “U.S. Securities Act”) or any state securities laws and may not be offered or sold within
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