Identifying Minerals Associated with Porphyry Copper

Exploring for porphyry copper deposits requires the accurate identification of pathfinder carbonate minerals. With an oreXpress spectrometer with EZ-ID and the USGS and optional SPECMin libraries, geologists can identify typical pathfinder minerals such as illite, azurite, and malachite, create a mineral map for the project area, and set up a cost-effective drilling plan for ongoing exploration. The oreXpress is a rugged geological spectrometer designed for field use.

The oreXpress with EZ-ID delivers:

  • Full range NIR field spectrometer – 350-2500nm
  • High resolution/high sensitivity scanning in a lightweight field package
  • Rugged reliable design with all photodiode arrays – no moving optical parts
  • EZ-ID mineral identification software matching your target samples against two libraries of more than 1600 spectra and 600 minerals
  • Contact probe and two lithium-ion batteries for a full day of fast scanning in the field

EZ-ID features:

  • Fast and accurate identification of an unknown mineral to a known spectral library sample
  • Simple, consistent user interface
  • USGS and SpecMIN libraries available
  • Weighted score for best matches
  • Include or exclude spectral regions of interest for optimal results
  • User-configurable batch processing and output to an Excel spreadsheet

In exploring for porphyry copper, samples indicated the presence of minerals that are related to copper deposits. Using EZ-ID, illite, azurite, and malachite were identified in samples from outcrops.

The data from this analysis can be used to create a mineral map for the project area and decide on spots for drilling that have the most potential. The oreXpress software interface (DARWin SP Data Acquisition software) saves all files as ASCII for use with other software packages in addition to our EZ-ID software. These ASCII files are easy to import into software for 3D modeling, mine mapping and more.

Field sample from outcrop

Illite with identification fine-tuned using match regions (shaded areas)

Azurite identification

Malachite identification

The EZ-ID screens showing the identification of illite, azurite, and malachite in our samples. The shaded regions in the screens are match regions that were user-selected to focus on key absorption features for better identification of the different minerals mixed in the sample.