IIRC another large portion of the differences between 2008 and 2012 was metal recoveries which I believe could make up a large chunk of the economic difference. Metal recoveries for 2012 can be seen here:
web.tmxmoney.com
"Notes to Mineral Resources Tables
...
| d) | CuEq grade cut-offs were used to report the mineral resource estimation as a function of copper, molybdenum, gold, and silver. The CuEq is based on Tetra Tech's long-range metal prices of US $2.97/lb for copper, US $16.80/lb molybdenum, US $1,256.00/oz gold and US $20.38/oz for silver and metal recoveries of 60.90% for molybdenum, 70.6% for gold and 43.4% for silver. No copper recoveries were applied to the copper equivalent grade;"
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whereas metal recoveries for 2008 are here:
copperfoxmetals.mwnewsroom.com
"MILL RECOVERIES
Mill recoveries are projected to be: copper to the copper concentrate: 88.4%, molybdenum to the molybdenum concentrate: 71.3%, gold to the copper concentrate: 81.3%, silver to the copper concentrate: 70.7%.
The grades of the copper concentrate are expected to be: copper, 33.85%, gold, 21.9 g/t, silver, 158.3 g/t.The grade of the molybdenum concentrate is 50.0%, and assays 368 ppm rhenium.The copper grade in the copper concentrate is higher grade than industry standard chalcopyrite concentrate because of the bornite content and should command a premium from smelters and refiners seeking this product. The rhenium content of the molybdenum concentrate is expected to possibly command a premium."
Looks like moly, gold and silver recoveries went down 10.4, 10.7 and 27.3% respectively. Now that's a large chunk of your revenue down the drain which I would think would shave a "tonne" off the NPV (no pun intended). So to me how can 4 years pass and the assumed metals recoveries actually drop? It's not like the deposit changed or humanity got worse at resource extraction. Were they too optimistic in 2008? Do BFS's have more stringent requirements for this? Who knows but this is just something else to add to the long list of things that don't add up... |
