Geostatistical methodology to characterize volcanogenic massive and stockwork ore deposits

David Silva, José Almeida

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The Zambujal ore deposit, Neves-Corvo mine, is a zoned volcanogenic sulfide deposit of copper and zinc, with massive ores at the top and stockwork ores at the bottom. Metal grades are strongly zoned by ore types. The main methodology hereby proposed combines geostatistical techniques so that an improved stochastic geological model of the Zambujal deposit encompassing morphology and grades is presented. The model of the morphology was made in two main steps. First, a 3D solid of the boundaries was created and then a 3D grid model of the local sulfide proportion was simulated. This latter variable was modeled by using rock specific gravity as a proxy. After that, a conditional grid model of relative copper grades, i.e., recalculated metal grades assuming only the sulfide content, is also simulated in accordance with the morphology. At the end, the new tool, metal tonnage cut-off surface, is proposed, which combines copper grades within massive ores and stockwork ores. To validate the results found, the global tonnages of copper obtained by Ordinary Kriging and the proposed methodology are compared.

Original languageEnglish
Article number238
JournalMinerals
Volume7
Issue number12
DOIs
Publication statusPublished - 1 Dec 2017

Keywords

  • Metal grade model
  • Morphological model
  • Neves-Corvo mine
  • Proportion of sulfide
  • Specific gravity as a proxy
  • Stochastic simulation
  • Sulfide ore deposit
  • Zambujal

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