Nickel, Copper and Cobalt Deportment
For the three samples, pentlandite contains 95.5 to 96.3% of the overall nickel in the sample while pyrrhotite hosts 2.7 to 4.0% and pyrite 0.02 to 0.17%. The silicate minerals (ortho- and clinopyroxene, amphibole and biotite / phlogopite) account for just 0.50 to 0.91% of the total nickel.
The copper in all three samples is contained entirely within chalcopyrite.
Cobalt is mainly contained within pentlandite (89.4%) in sample L163163 but in samples L163164 and L163593 it is split about evenly between pentlandite (45.4 to 54%) and pyrite (46 to 54.6%).
The P80s (80% passing criteria, represents the particle or mineral grain size at which 80% is finer than this value) of the minerals and overall particles are presented in Table 2.
To view "Table 2: P80s of Minerals Calculated by QEMSCAN (by mass).", please visit the following link: http://media3.marketwire.com/docs/611vms_tab2.jpg.
Liberation Characteristics of Pentlandite and Chalcopyrite
In QEMSCAN liberation analysis, particles are classified into the following categories based on the exposed 2D surface area of the mineral-of-interest in percent:
Free = greater than 95% surface area exposure of pentlandite (Pn) or chalcopyrite (Cpy).Liberated = greater than 80 surface area exposure of Pn or Cpy.Non-Liberated but Pn (or Cpy) with other mineral(s) combined show greater Floatable = than 95% surface area exposure, where Pn (or Cpy) shows greater than 20% surface area exposure.Not Floatable = Pn (or Cpy) with greater than 20% surface area exposure combined with two or more other mineral groups or Pn (or Cpy) surface exposure is less than 20%.
The predicted flotation characteristics for pentlandite and chalcopyrite are summarized in tables 3 and 4, respectively. Total potentially floatable pentlandite ranges from 96.3 to 97.6% and total potentially floatable chalcopyrite ranges from 87.1 to 95.4%.
To view "Table 3: Prediction of Flotation Characteristics of Pentlandite.", please visit the following link: http://media3.marketwire.com/docs/611vms_tab3.jpg.
To view "Table 4: Prediction of Flotation Characteristics of Chalcopyrite", please visit the following link: http://media3.marketwire.com/docs/611vms_tab4.jpg.
Mineralogically limiting grade-recovery analyses provide an indication of the theoretical maximum achievable elemental grade by recovery, based on the calculated mass of minerals and the total mass in each liberation category (individual particle liberation and grade). It is important to note that these results do not reflect any other physical factors (or flotation reagent kinetics) that could occur in the actual metallurgical process, such as possible fine-grained (less than 10 um) sulphide and/or gangue entrainment (diluents) or very fine sulphide intergrowths on liberated grains that would make selective flotation difficult. Therefore, predicted results show much higher grade-recovery relationships than are actually achievable from the process. Nevertheless they do provide an indication of the potential nickel and copper recoveries. The mineralogically limiting grade-recovery curves for nickel and copper are presented in figures 1 and 2.