XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1475
Silver Grain Exposure in Ore Particles
Based on a previous QEMSCAN analysis, it is known that
the acanthite found in the selected orebody is around 10
µm in size and there are association of silver in lead min-
eral phases, including both lead sulfide and sulfate. It was
decided for the 3D imaging to combine the silver-rich lead
minerals and acanthite minerals to be considered as silver
grains. The silver grade of the selected ore was below 0.5
oz/t. At least a few thousands of particles were scanned to
find a single particle containing a silver grain. The silver
and lead minerals were justified by the X-ray attenuation of
mineral standards in the same XCT scan. Eleven ore parti-
cles were found to contain acanthite grains and lead miner-
als, which is consistent with previous QEMSCAN results.
Figure 9 shows the 3D representations for the silver
ore particles from selected size fractions. Green color is the
gangue minerals, mostly silicate. Red is acanthite, and blue
is silver-rich lead minerals. Some silver grains are exposed at
the particle surface. However, there are certain amount of
silver grains that are inside the particles. In Figure 9, there
are bubble-like green shapes inside the particles, which are
the pores and cracks of particles. As discussed in Section
3.2, the micro-cracks/pores are important for sub-surface
fluid transportation of ore particles and the corresponding
metal extraction in heap leach. It is expected that the silver
grains exposed at the particle surface would be leach much
faster than the ones that are internal.
A total of 256 silver grains were identified in eleven
ore particles. Their grains size is reported in Figure 10. The
grains size distribution from 3D analysis by XCT is consis-
tent with the QEMSCAN results. The majority of the silver
grains are smaller than 20 μm.
CONCLUSIONS
Leach columns were scanned at the voxel size of 68 μm to
determine the permeability and porosity after completion
of the leach cycle. It was shown in the controlled PSD 4"
columns that an increase in fine particles can result in the
agglomeration of fines and can decrease the pore connectiv-
ity and permeability in the packed particle bed.
The 3D images of selected ore particles crushed by
plant-scale HPGR indicated that the higher specific pres-
sure resulted in more significant internal fractures. The 3D
crack shapes inside particles in selected size fractions indi-
cated particle damage features like pores, close-to-surface
cracks, and impact cracks.
3D scanning of a few thousand ore particles at the voxel
size of a micron or sub-micron found the ones containing
Color code: green, gangue red, acanthite blue, silver-rich lead minerals.
Figure 9. 3D images of single particles in the selected size fractions for heap leach feed
Silver Grain Exposure in Ore Particles
Based on a previous QEMSCAN analysis, it is known that
the acanthite found in the selected orebody is around 10
µm in size and there are association of silver in lead min-
eral phases, including both lead sulfide and sulfate. It was
decided for the 3D imaging to combine the silver-rich lead
minerals and acanthite minerals to be considered as silver
grains. The silver grade of the selected ore was below 0.5
oz/t. At least a few thousands of particles were scanned to
find a single particle containing a silver grain. The silver
and lead minerals were justified by the X-ray attenuation of
mineral standards in the same XCT scan. Eleven ore parti-
cles were found to contain acanthite grains and lead miner-
als, which is consistent with previous QEMSCAN results.
Figure 9 shows the 3D representations for the silver
ore particles from selected size fractions. Green color is the
gangue minerals, mostly silicate. Red is acanthite, and blue
is silver-rich lead minerals. Some silver grains are exposed at
the particle surface. However, there are certain amount of
silver grains that are inside the particles. In Figure 9, there
are bubble-like green shapes inside the particles, which are
the pores and cracks of particles. As discussed in Section
3.2, the micro-cracks/pores are important for sub-surface
fluid transportation of ore particles and the corresponding
metal extraction in heap leach. It is expected that the silver
grains exposed at the particle surface would be leach much
faster than the ones that are internal.
A total of 256 silver grains were identified in eleven
ore particles. Their grains size is reported in Figure 10. The
grains size distribution from 3D analysis by XCT is consis-
tent with the QEMSCAN results. The majority of the silver
grains are smaller than 20 μm.
CONCLUSIONS
Leach columns were scanned at the voxel size of 68 μm to
determine the permeability and porosity after completion
of the leach cycle. It was shown in the controlled PSD 4"
columns that an increase in fine particles can result in the
agglomeration of fines and can decrease the pore connectiv-
ity and permeability in the packed particle bed.
The 3D images of selected ore particles crushed by
plant-scale HPGR indicated that the higher specific pres-
sure resulted in more significant internal fractures. The 3D
crack shapes inside particles in selected size fractions indi-
cated particle damage features like pores, close-to-surface
cracks, and impact cracks.
3D scanning of a few thousand ore particles at the voxel
size of a micron or sub-micron found the ones containing
Color code: green, gangue red, acanthite blue, silver-rich lead minerals.
Figure 9. 3D images of single particles in the selected size fractions for heap leach feed