30.01.2015 Views

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

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

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

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

• Development of pre-feasibility level design for <strong>the</strong> HTMF based <strong>on</strong> <strong>the</strong> proposed c<strong>on</strong>cept<br />

• Development of a schedule of materials and quantities for inclusi<strong>on</strong> in pre-feasibility<br />

study ec<strong>on</strong>omic assessment by o<strong>the</strong>rs<br />

General<br />

No site investigati<strong>on</strong>s have been completed at this stage of <strong>the</strong> <strong>project</strong>. The site characteristics<br />

at <strong>the</strong> Hydrometallurgical Plant site presented below are based <strong>on</strong> informati<strong>on</strong> from a desktop<br />

review.<br />

The topography of <strong>the</strong> site can be described as flat to gently sloping, generally to <strong>the</strong> north.<br />

Topography around <strong>the</strong> HTMF area typically ranges between 190 and 220 MASL and<br />

decreases to approximately 160 MASL al<strong>on</strong>g <strong>the</strong> south shore of Great Slave Lake.<br />

Seismicity<br />

The central regi<strong>on</strong> of <strong>the</strong> Northwest Territories is historically a quiet earthquake z<strong>on</strong>e. A seismic<br />

hazard assessment was previously completed for <strong>the</strong> TLP using probabilistic calculati<strong>on</strong>s based<br />

<strong>on</strong> design tables from <strong>the</strong> 2005 Nati<strong>on</strong>al Building Code of Canada.<br />

The maximum accelerati<strong>on</strong> for <strong>the</strong> <strong>project</strong> site ranged from 0.007 g for a 1 in 100 year return<br />

period to 0.16 g for a 1 in 10,000 year return period. A review <strong>the</strong> Thor Lake site TMF<br />

c<strong>on</strong>sequence classificati<strong>on</strong> following <strong>the</strong> Canadian Dam Associati<strong>on</strong> 2007 Dam Safety<br />

Guideline classified <strong>the</strong> TMF as ‘Significant’. The resulting earthquake design ground moti<strong>on</strong> is<br />

a 1 in 1,000 year event which corresp<strong>on</strong>ds to a maximum accelerati<strong>on</strong> of 0.035 g for <strong>the</strong> Thor<br />

Lake Project site.<br />

The seismic design criteria and c<strong>on</strong>sequence classificati<strong>on</strong> previously completed for <strong>the</strong> Thor<br />

Lake site has been assumed to be adequate for <strong>the</strong> purposes of <strong>the</strong> HTMF pre-feasibility study.<br />

A site specific seismic review is recommended for <strong>the</strong> HTMF during <strong>the</strong> next phase of<br />

engineering.<br />

Tailings Characteristics<br />

There is no direct informati<strong>on</strong> available c<strong>on</strong>cerning <strong>the</strong> physical characteristics of <strong>the</strong><br />

Hydrometallurgical tailings stream. Some assumpti<strong>on</strong>s regarding <strong>the</strong> physical characteristics of<br />

<strong>the</strong> tailings have been made and are outlined below:<br />

• Specific Gravity: The tailings solids from <strong>the</strong> proposed milling process are<br />

predominantly gypsum (approx. 84%) which are expected to be similar to<br />

phosphogypsum tailings in terms of void ratio, dry densities and c<strong>on</strong>solidati<strong>on</strong> properties<br />

Technical Report 43-101 – March 13, 2011 Page 18-46<br />

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

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!