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Extension Project for
Fortaleza de Minas Mine
Votorantim Metais:
Miguel S. Kato
Thiago N. Teixeira
Silvia M. Santana
• 1983 – The deposit is discovered;
• 1995 – Project approval and construction start;
• 1997 – Beginning open pit operation and
concentration;
MINE HISTORY
• 1998 – Beginning underground mine access;
• 2003 – Announcement of the closure of the mine;
• 2004 – Votorantim Metais buys Fortaleza de Minas;
• 2009 – Beginning the extension project;
INTRODUTION
• LOM estimated middle 2011;
• Because of the rock host quality the actual mining method
has;
� High dilution;� High dilution;
� Mining cost is very expensive;
� Low recoveries;
• Necessity to change the mining method;
FORTALEZA DE MINAS MINE
ZONA NORTE
AREA CENTRALZONA FORMIGA
• NSR (Net Smelter Return) methodology:
� The cut-off consider:
� Mining costs;
� Royalties;
RESERVE ESTIMATION
� Royalties;
� G&A;
� The process cost is included in the NSR calculation.
• Sublevel-Stope (AVOCA)
Actual Mining Method
REMAINING AVOCA STOPES
CUT AND FILL SCENARIO
CUT AND FILL SCENARIO
• Development section from 4m to 3m;
• Cut and fill still has high dilution;
CUT AND FILL SCENARIO
• Low production rates;
• Necessary to study a different scenario
UP HOLE SCENARIO
UP HOLE SCENARIO
UP HOLE PRODUCTION SEQUENCE
• The proposed method is very selective and with low dilution;
• The filling will provide greater stability to the rock mass;
• The mine has already made two experimental mining and the results demonstrate alignment with the rates adopted in the project;
CONCLUSION
• For the unit the continued operation of the mine has an important impact on the smelter. Because the nickel concentrate produced by the mine itself is cheaper than those concentrated acquires from other companies, it has also an important role in the concentrates blending, for being the most energetic and least contaminated of all.
QUESTIONS
THANK YOU