Mr. Theo van der Linde reports
CORONET ANNOUNCES HYDROMETALLURGICAL RESULTS ON TAILINGS AND DUMPS
Coronet Metals Inc. has successfully completed the first round of hydrometallurgical tests on its gold-bearing tailings and dumps at its 100-per-cent-owned White Caps gold mining project. This is part of an extensive work program that will form the basis to verify and possibly upgrade the historical estimates of the quantity of the gold-bearing tailings and mine dumps to a National Instrument 43-101 mineral resource (supported by an independent technical report) or mining reserve (supported by either a preliminary feasibility study or a feasibility study).
The hydrometallurgical testwork was performed by EnviroLeach Technologies Inc., a 100-per-cent wholly owned subsidiary of Iberian Minerals. Met-Solve Laboratories and ALS Global performed independent verification of the sample solutions and solids.
The patent-pending, environmentally friendly, non-cyanide-based leach formula EnviroLeach was used on the gold-bearing tailings and mine dumps to determine and optimize recoveries of gold.
The representative samples were taken from four different locations that collectively makes up the gold-bearing tailings and mine dumps:
- Bill placer;
- White Caps dumps;
- Pink tails;
- Brown tails.
Highlights of the hydrometallurgical testwork are summarized as follows:
- Head grades of 5.43 grams per tonne (g/t) on the Pink tails;
- Head grades as high as 15.94 g/t on the White Caps dumps (minus 35 mesh);
- Recovery as high as 70.74 per cent in six hours and 87.24 per cent in 24 hours on the Brown tails;
- Recovery as high as 71.52 per cent in 24 hours on the White Caps dumps (minus 35 mesh).
"These results are very encouraging and far better than we hoped for. Given these results, further testwork including bulk sampling and pilot plant testing with EnviroLeach is justified. We plan to demonstrate economic viability by working towards a feasibility study, and that will enable Coronet to unlock the project's cash flow potential," said Theo van der Linde, president of Coronet.
Compared with hydrometallurgical testwork performed at a lab in Denver in 2012 on similar samples employing cyanide, the x-leach showed significant improvement in recoveries using the EnviroLeach solution versus cyanide. The x-leach residence time was three times shorter (24 hours versus 72 hours) with 295-per-cent-better recoveries on the Pink tails, 278 per cent better on the Brown tails, 170 per cent better on the Bill placer and almost identical recoveries on the White Caps dumps.
Recovery (%)
Type of Grind PH Cyanide Leach Leach Pink Brown Bill White Caps
leach strength enhancer time tailings tailings placer dumps
-50 mesh -35 mesh
X-leach No 11 N/A No 24 hours 55.25% 87.24% 73.04% 71.52%
Cyanide Yes -- P80200 mesh 11 2.0 g/l Yes -- 200 g/t 72 hours 14.00% 23.10% 27.10% 73.40%
(75 microns) NaCN lead nitrate
Approximately five kilograms each of the Bill placer, White Caps dumps, Pink tails and Brown tails were provided for testing. Bottle roll tests were done on the samples at different particle size for the Bill placer and White Caps dumps samples due to the variety of sizes in the samples. For the Bill placer, particle size of minus 50 mesh was tested. The White Caps dumps were split into minus 35 mesh and minus six to plus 35 mesh sizes to implement the test.
The first test was done for 24 hours leach time, and intermediate samples were taken in the first, third and sixth hour. Fifty grams of the solid samples were leached in 150 millilitres of the leachant on the bottle rolls, which is equal to 25-per-cent pulp density. Residue grades and 24-hour solution grades have been independently certified by ALS and Metsolve lab, respectively. Head grades are achieved by the sum of residue grades and effective grades at the end of the leach time (24th hour). Residues assayed by ALS, Brown tails, White Caps minus 35 mesh and White Caps minus six mesh plus 35 mesh residues, were pulverized by ALS, as there were coarse particles in the samples.
Coronet and EnviroLeach Technologies are very confident that with adjusting the x-leach formula, together with further testwork on the Pink tails, Brown tails and White Caps dumps, the recoveries will significantly improve during the second round of testwork. The second round of testwork, which is presently under way, will include detailed screen analysis and optimizing the x-leach formula.
Upon completion of this round of testwork, a decision is anticipated with respect to commencement of work on a pilot plant to treat the tails and begin recovering gold at the White Caps property.
The attached table shows the test result in 24 hours where intermediate samples were taken in first, third and sixth hours.
EFFECTIVE GRADES OF THE SAMPLES IN 24 HOURS
Time Pink Brown Bill White Caps White Caps dumps
(hrs) tails tails placer dumps -6 mesh to +35 mesh
-50 mesh -35 mesh
1 1.19 5.79 2.61 5.23 0.20
3 2.37 8.30 2.76 9.31 0.35
6 2.54 11.58 3.19 11.21 0.47
24 3.00 13.26 3.63 11.40 0.54
Residue 2.43 1.94 1.34 4.54 5.55
Calculated
head 5.43 15.20 4.97 15.94 6.09
The attached table shows the recovery rate of each sample during a 24-hour leach time.
RECOVERY RATE (%) IN 24 HOURS
Time Pink Brown Bill White Caps White Caps dumps
(hrs) tails tails placer dumps -6 mesh to +35 mesh
-50 mesh -35 mesh
1 21.92 35.37 39.61 17.59 2.98
3 43.65 50.70 41.88 31.30 5.21
6 46.78 70.74 48.41 37.69 6.99
24 55.25 87.24 73.04 71.52 8.87
Fred Tejada, PGeo, a director of the company, is a qualified person under the meaning of Canadian National Instrument 43-101 and is responsible for the technical information contained in this news release.
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