We compare ore-grain content robustness estimations based on two induced polarization (IP) parameters: the chargeability and the total chargeability. We obtained IP decays with a conventional time domain (TD) technique and a lab low-current transmitter in the time range from 0,3 ms to 8s. We show dependence of the chargeability and of the total chargeability on the ore volumetric content (varied between 0,6 and 30%), for different grain radii (varied between 0,045 and 0,55 mm), different mineral composition (pyrite (FeS2), galena (PbS), graphite (C), magnetite (Fe3O4) and cryptomelane (K2-XMn8O16)) and different pore water electrical conductivity (varied between 2,5. 10-3 and 10-1 S/m). We found that the total chargeability is strongly dependent on the ore volumetric content and is almost independent of the grain mineral composition, size, as well as of the pore water conductivity. From the measurements we obtained the relaxation time distributions (RTD). We showed that for the models of disseminated ores containing bimodal grain-size distribution we recovered bimodal relaxation time distributions (RTD). Variations of the ore volumetric content in these models don't shift the RTD maximum positions, but leads to variations of their amplitudes. Th e chargeability calculated for the models containing bimodal grain-size distribution shows a weak dependence on the ore volumetric content in a small grains size range, while the total chargeability strongly depends on the ore content in the whole grain size range. Our data show that the total chargeability is a proxy for the ore content. Refs 21. Figs 4. Table 2.
|Журнал||Vestnik Sankt-Peterburgskogo Universiteta, Seriya Geologiya i Geografiya|
|Состояние||Опубликовано - 1 янв 2014|
Предметные области Scopus
- Планетоведение и науки о земле (все)