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

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Mine Fan Horse Power<br />

Using <strong>the</strong> same formulas as noted above <strong>the</strong> head loss for 300,000 cfm air flow is estimated to<br />

be 6.2” WG and <strong>the</strong> air horse power is estimated to be 300 hp. As part of <strong>the</strong> mine expansi<strong>on</strong> it<br />

will be necessary to install a larger motor <strong>on</strong> <strong>the</strong> main fan.<br />

Scott Wils<strong>on</strong> RPA recommends that fur<strong>the</strong>r planning and analysis be completed to determine<br />

<strong>the</strong> optimum fan and motor combinati<strong>on</strong> for <strong>the</strong> initial ventilati<strong>on</strong> and for <strong>the</strong> increased air flow at<br />

<strong>the</strong> expanded rate.<br />

DEWATERING<br />

The mine is not expected to be a “wet” mine and ground water inflows are expected to be low<br />

with a maximum estimated 50 gpm of groundwater inflow into <strong>the</strong> mine. The estimate of<br />

groundwater inflow has been based up<strong>on</strong> <strong>the</strong> observati<strong>on</strong>s of <strong>the</strong> numerous core drill programs<br />

and observati<strong>on</strong>s from <strong>the</strong> test mine previously developed at <strong>the</strong> Thor <strong>lake</strong> site.<br />

The estimated water inflow is:<br />

• Groundwater 50 gpm<br />

• Drilling – 2 gpm/ boom – 10 gpm<br />

• Diam<strong>on</strong>d drilling 10 gpm<br />

• Mine dust suppressi<strong>on</strong> – carried <strong>on</strong> rock<br />

• Crusher dust c<strong>on</strong>trol – 7 gpm (Melis)<br />

Excess water from backfill has not been c<strong>on</strong>sidered as backfill plans call for <strong>the</strong> use of paste fill<br />

and <strong>the</strong> plan would be to use a fill which used all of <strong>the</strong> c<strong>on</strong>tained water for hydrati<strong>on</strong> of <strong>the</strong><br />

binder.<br />

The total estimated water inflow is approximately 80 gpm. All water will be diverted to <strong>the</strong> base<br />

of <strong>the</strong> decline ei<strong>the</strong>r al<strong>on</strong>g <strong>the</strong> decline or by boreholes specifically installed for mine drainage.<br />

At <strong>the</strong> base of <strong>the</strong> decline <strong>the</strong>re will be two sumps each with a length of 50 m to provide time for<br />

settling. Clear overflow water will be pumped to a small sump adjacent to <strong>the</strong> main dewatering<br />

pumps using low head pumps. From <strong>the</strong> main dewatering sump <strong>the</strong> water will be pumped to<br />

surface to join <strong>the</strong> mill tailings stream.<br />

The two sumps will be used in an alternate fashi<strong>on</strong> with <strong>on</strong>e in operati<strong>on</strong> and <strong>the</strong> o<strong>the</strong>r being<br />

drained and cleaned of slimes.<br />

Technical Report 43-101 – March 13, 2011 Page 18-26<br />

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

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