Great Quest Receives Positive Results From Beneficiation Tests of Tilemsi Phosphate
VANCOUVER, BC -- John Clarke, CEO of Great Quest Metals Ltd. ("Great Quest" or the "Company") (TSX-V:GQ) is pleased to announce the successful completion of initial beneficiation tests carried out on the Tilemsi Phosphate Project in Eastern Mali by MINTEK South Africa and the Company's consultant Gaya Resources Development ("Gaya").
Phosphate rock from the Tilemsi Project displayed good characteristics for effective beneficiation. Samples used in the beneficiation tests assayed between 26% and 32% P2O5. Phosphate primarily exists in the larger size fractions, with 98% recovery achieved by screening for material larger than 106 microns. Silica, aluminum and iron can be reduced by screening off the fine fractions. The screen beneficiated (+ 106 microns) phosphate grades assayed between 30.3% and 34.9% P2O5.
Bulk phosphate samples were collected from 11 representative pits twinned with previously drilled resource definition RC drill holes during the Tilemsi phase 2 drill program (described in Great Quest press release of February 1st, 2012). The bulk samples provided the basis for phosphate test work being completed at the MINTEK laboratories in Johannesburg as part of the evaluation of Tilemsi phosphate for future project development. The work encompasses process options for mineral beneficiation, product granulation and solubility profiles of processed Tilemsi ores.
The granulation of Tilemsi phosphate rock (as reported in the Great Quest press release dated 7th March, 2012) should be feasible with relative ease with the use of a rotating pan. Successful granulation is an important step for the development of a low cost phosphate product for local use. The success of creating a local fertilizer product for the West African region hinges on keeping costs low and making the product transportable. The product showed excellent potential for optimal granulation. The results of the current solubility test work on the Tilemsi phosphate ores will be completed and released shortly.
The head assay for the 11 pit samples collected during the phase 2 drill program are presented in Table 1 below.
Table 1: Head Sample Chemical Analysis
| Sample No. | % P2O5 | %CaO | %SiO2 | %Al2O3 | %Fe2O3 |
|---|---|---|---|---|---|
| 6001 | 28.3 | 35.4 | 10.9 | 2.94 | 6.4 |
| 6002 | 28.2 | 35.6 | 10.7 | 3.06 | 6.4 |
| 6003 | 26.0 | 32.9 | 14.9 | 4.01 | 7.1 |
| 6004 | 29.2 | 37.8 | 10.6 | 2.74 | 5.9 |
| 6005 | 25.6 | 33.0 | 14.9 | 4.06 | 7.0 |
| 6006 | 27.5 | 36.5 | 11.2 | 3.25 | 6.5 |
| 6028 | 31.1 | 39.1 | 6.9 | 2.21 | 6.3 |
| 6029 | 31.5 | 39.8 | 6.3 | 2.55 | 6.3 |
| 6030 | 30.9 | 39.1 | 6.1 | 2.19 | 5.7 |
| 6063 | 27.9 | 35.0 | 9.4 | 3.00 | 6.4 |
| 6066 | 32.2 | 39.0 | 5.2 | 2.83 | 5.7 |
The 11 pit samples were wet screened to determine their respective particle size distributions and each size fraction was analysed for P2O5 and for each of the other key oxides (including CaO, SiO2, AL2O3, and Fe2O3). The size fraction analysis by weight for the 11 pits is presented in Table 2 below.
Table 2: % weight at each size fraction (1000µ = 1 mm)
| % weight at each size fraction (1000μ = 1 mm) | ||||||||
|---|---|---|---|---|---|---|---|---|
| Pit Number | 1000 µ | 850 µ | 500 µ | 212 µ | 106 µ | 75 µ | 45 µ | 38 µ |
| 6001 | 42.7 | 14.4 | 22.5 | 10.8 | 2.0 | 2.0 | 0.4 | 5.3 |
| 6002 | 50.3 | 13.6 | 19.2 | 10.6 | 1.8 | 1.6 | 0.3 | 2.6 |
| 6003 | 38.5 | 12.5 | 18.1 | 14.4 | 2.3 | 2.5 | 0.5 | 11.2 |
| 6004 | 51.5 | 10.8 | 18.5 | 10.3 | 1.9 | 2.2 | 0.5 | 4.3 |
| 6005 | 35.0 | 11.3 | 20.0 | 16.5 | 2.4 | 3.1 | 0.7 | 11.1 |
| 6006 | 40.2 | 13.8 | 18.6 | 9.8 | 1.9 | 2.1 | 0.4 | 13.0 |
| 6028 | 67.2 | 7.3 | 13.6 | 7.4 | 1.0 | 1.1 | 0.2 | 2.2 |
| 6029 | 68.4 | 6.6 | 11.1 | 6.6 | 1.1 | 1.3 | 0.2 | 4.8 |
| 6030 | 62.2 | 7.9 | 12.6 | 6.8 | 1.0 | 0.9 | 0.2 | 8.2 |
| 6063 | 50.6 | 10.7 | 17.0 | 9.4 | 1.5 | 1.5 | 0.3 | 9.0 |
| 6066 | 69.0 | 9.6 | 10.0 | 4.3 | 1.3 | 1.3 | 0.2 | 4.3 |
The size fraction analysis data and the P2O5 and oxide concentrations in each size fraction allowed the cumulative distribution of P2O5 and other oxides to be determined. These are presented in Table 3 below for pit 6001 which was representative of the complete data set.
Table 3: Cumulative % P2O5 (AL2O3, SiO2, Fe2O3, and CaO) Retained at each size fraction for sample 6001
| Cumulative % P2O5 (AL2O3, SiO2, Fe2O3, and CaO) Retained at each size fraction (1000μ = 1 mm) | ||||||||
|---|---|---|---|---|---|---|---|---|
| 1000μ | 850μ | 500μ | 212μ | 106μ | 75μ | 45μ | 38μ | |
|
P2O5 % |
56.5 | 71.4 | 90.4 | 98.4 | 99.0 | 99.4 | 99.5 | 99.6 |
|
AL2O3 % |
2.3 | 15.3 | 49.7 | 67.7 | 73.2 | 78.2 | 79.1 | 80.9 |
|
SiO2 % |
2.2 | 6.1 | 33.1 | 57.6 | 62.7 | 71.7 | 73.8 | 76.5 |
|
Fe2O3 % |
24.4 | 33.5 | 58.2 | 74.2 | 77.4 | 82.6 | 83.5 | 85.7 |
|
CaO % |
45.9 | 63.2 | 87.7 | 97.1 | 98.6 | 99.3 | 99.4 | 99.5 |
Table 3 above provides the basis for the potential for future successful beneficiation of Tilemsi phosphate. It shows that for the sample from pit 6001 that 99.0 % of its P2O5 content lies within those particles that are greater than 106 μ (microns) in size. Thus removing the minus 106 μ material could represent a loss of only 1% of the total P2O5 content of the sample from pit 6001. For the same pit sample, screening at 106 μ would retain only 62.7 % of the silica (SiO2) and 77.4 % of the iron oxide (FE3O4) content. Thus screening could be considered as a route to upgrade the phosphate content of the Tilemsi phosphate samples while simultaneously reducing some of the 'unwanted' oxide contents such as silica and iron oxide.
Table 4 below shows the effect of screening at 106 μ for all 11 pit samples.
Table 4: Chemical Analysis of Particles Greater than 106μ
| 6001 | 6002 | 6003 | 6004 | 6005 | 6006 | 6028 | 6029 | 6030 | 6063 | 6066 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Weight % >106 µ |
90.32% | 93.67% | 83.52% | 91.04% | 82.72% | 82.54% | 95.51% | 92.67% | 89.64% | 87.66% | 92.92% |
|
% P2O5 |
30.3 | 30.7 | 32.5 | 31.2 | 31.1 | 32.9 | 34.3 | 34.8 | 34.9 | 32.6 | 33.0 |
|
% Fe2O3 |
5.5 | 6.8 | 5.6 | 5.2 | 5.9 | 5.7 | 5.7 | 4.7 | 4.7 | 5.0 | 5.8 |
|
% SiO2 |
5.7 | 8.8 | 7.7 | 4.5 | 8.5 | 6.1 | 5.3 | 2.4 | 3.7 | 5.2 | 6.2 |
|
% AL2O3 |
2.4 | 2.4 | 1.7 | 1.9 | 2.3 | 1.3 | 1.4 | 1.1 | 1.1 | 1.2 | 2.4 |
|
% CaO |
44.0 | 40.6 | 44.8 | 41.1 | 39.1 | 41.6 | 39.7 | 45.3 | 47.9 | 44.6 | 39.1 |
|
Increase in % |
+2.0 | +2.5 | +6.5 | +2.0 | +5.5 | +5.4 | +3.2 | +3.3 | +4.0 | +4.7 | +0.8 |
|
Upgrade % |
7.1% | 8.9% | 25.0% | 6.8% | 21.5% | 19.6% | 10.3% | 10.5% | 12.9% | 16.8% | 2.5% |
Key observations:
Prior to beneficiation, Tilemsi phosphate is high grade and assays between 25.6% and 31.5% P2O5. The screen beneficiated (+ 106 micron) phosphate grades assayed between 30.3% and 34.9% P2O5.
The P2O5 primarily exists in the +106 micron range (>98% recovery P2O5). Below that size, the P2O5 levels drop off significantly and the ore could be enriched by screening (removing) at around this particle size, the undersize could be a fine reject.
The silica, aluminium, and iron oxide can be reduced by screening the fines fractions which may enable the AL2O3 and SiO2 levels to be reduced by 44%.
Commenting, Dr. John Clarke, CEO of Great Quest Metals said, "The Company is pleased that the results of our beneficiation tests show that Tilemsi phosphate may be successfully beneficiated utilising simple process techniques to raise an already high grade material to an even greater product purity through removing extraneous contents."
Beneficiation opportunities requiring further testwork:
Residual concentrations of Fe2O3 are around 5.5%. This may be able to be reduced further by utilising techniques such as magnetic separation. This will need to be investigated. It might be possible to further reduce the silica, aluminium, and iron oxide by attrition prior to screening to remove surface coatings if they are present.
Should even higher concentrate grades be required, it could be possible to screen the material at 500 microns with a loss of P2O5 of only around 10%. This option could also enable the process to discard an additional 10% of the residual Fe2O3.
Qualified Person Jed Diner (M.Sc., P. Geol.) is the Qualified Person responsible in accordance with NI 43-101 for the content, review and approval of this News Release. Mr. Diner completed his M.Sc. in Applied Earth Science at Stanford University and works internationally on mineral exploration and resource development projects. He has consulted on other phosphate projects in Uzbekistan, Peru and Angola.
ON BEHALF OF THE BOARD OF DIRECTORS
OF GREAT QUEST METALS LTD.
John A Clarke
CEO
Great Quest Metals Ltd. is a Canadian mineral exploration company with assets in Mali, West Africa. The Company is focused on developing the Tilemsi Phosphate Project, encompassing 1206 sq km in eastern Mali. The Company also holds several gold concessions in the productive Birimian gold belt in western Mali. Great Quest is listed on TSX Venture Exchange (GQ), and the Frankfurt Stock Exchange (GQM).
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