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technical report on the nechalacho deposit, thor lake project ...

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16. MINERAL PROCESSING AND<br />

METALLURGICAL TESTING<br />

METALLURGICAL TESTING<br />

Numerous metallurgical tests have been c<strong>on</strong>ducted over <strong>the</strong> last two years to determine how<br />

best to recover <strong>the</strong> valuable elements from Thor Lake Basal Z<strong>on</strong>e ore. The results of <strong>the</strong>se<br />

tests and brief ec<strong>on</strong>omic trade-off studies have led to <strong>the</strong> selecti<strong>on</strong> of a process including<br />

grinding, froth flotati<strong>on</strong>, decompositi<strong>on</strong> of <strong>the</strong> refractory rare earth, zirc<strong>on</strong>ium, and niobiumtantalum<br />

minerals and recovery of <strong>the</strong>se elements from soluti<strong>on</strong> by solvent extracti<strong>on</strong> and<br />

precipitati<strong>on</strong> methods.<br />

Metallurgical tests were completed <strong>on</strong> representative samples, both geographically and<br />

geologically, of <strong>the</strong> Upper and Basal Z<strong>on</strong>es of <strong>the</strong> <strong>deposit</strong>, prepared in 2008, 2009 and 2010.<br />

The samples were developed from multiple drill holes, with composites comprising of numerous<br />

samples across <strong>the</strong> mineralized z<strong>on</strong>es.<br />

MINERALOGY<br />

The mineralogy of <strong>the</strong> mineralized material from <strong>the</strong> Thor Lake Deposit ore has been detailed in<br />

Secti<strong>on</strong> 9 of this <str<strong>on</strong>g>report</str<strong>on</strong>g>. The important minerals are zirc<strong>on</strong>, allanite, m<strong>on</strong>azite, fergus<strong>on</strong>ite,<br />

bastnaesite, and synchysite. The minerals of interest are fine-grained and typically in <strong>the</strong> 5 to 25<br />

µm size range.<br />

COMMINUTION<br />

Five carefully selected composite samples of Upper Z<strong>on</strong>e (UZ) and Basal Z<strong>on</strong>e (BZ) material<br />

and waste rock were prepared and submitted to Starkey and Associates for SAGDesign testing<br />

and to SGS Lakefield Research Limited (SGS) for assessment of comminuti<strong>on</strong> properties.<br />

SGS <str<strong>on</strong>g>report</str<strong>on</strong>g>ed a B<strong>on</strong>d metric rod mill work index value of 16 kWh/t for a UZ sample and values<br />

of 14 kWh/t and 16.5 kWh/t for two BZ samples. The values show rock of average toughness<br />

according to <strong>the</strong> SGS database.<br />

SGS measured <strong>the</strong> abrasi<strong>on</strong> indices at 0.3 to 0.4 g indicating moderately abrasive material.<br />

B<strong>on</strong>d ball mill work index tests returned metric values of about 15 kWh/t for all samples with<br />

very little variati<strong>on</strong> when tested using 75 and 106 µm closing screens.<br />

Technical Report 43-101 – March 13, 2011 Page 16-1<br />

Prepared by Aval<strong>on</strong> Rare Metals Inc.

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