XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 403
access to an optimum amount of ore, whilst minimizing
waste movement. From these shells, production schedules
and therefore overall project economics can be defined (see
Figure 3). The blocks sitting behind the pit shell develop-
ment are populated with parameters relating to the grade
and mineral composition and other key factors. Sorting
amenability and the scale of separation generally do not fit
well with traditional block sizes.
The usual destinations for material mined are combina-
tions of direct plant feed, low grade stockpiles/leaching and
barren waste. There are several complications introduced by
sorting and preconcentration, with the most obvious being:
• Not all ore blocks sent to the plant will be accepted
as feed
• Rejected plant feed may qualify as either low grade
or waste
• Streams split by a sorting process will potentially
report to diverse final geographic locations and
• Accept to reject ratio will potentially vary by indi-
vidual mining block.
Without sorting, the well understood linear progression
from block model to pit shells to schedules and economics
can be quickly and efficiently addressed. If sorting is added
into the mix, it will have a major bearing on total material
movement, plant feed rate, recovery and mass flows to vari-
ous locations. As a consequence, pit shells, schedules and
economic considerations will need to change and therefore,
ensuring sorting is incorporated into the study, at an early
stage, is essential.
Gathering of sorting data requires higher resolution
investigations. In this regard, it is entirely likely that the
input will not be available sufficiently early to be used as an
input into the normal pit design and economic evaluation.
The consequence of such a lag is that it is hard to retrofit
sorting results back into an existing economic evaluation,
particularly if some physical decisions have been hard-
wired into the overall design, i.e., location of processing
plant or waste dumps.
IMPROVED INTEGRATION OF SORTING
AND PRECONCENTRATION INTO
STUDIES
The preconcentration behaviour of an orebody has to be
defined to the same level of confidence as any other pro-
cess step. Such performance definition requires access to
Source: Bearman et al., 2019
Figure 2. Suggested decision support process
access to an optimum amount of ore, whilst minimizing
waste movement. From these shells, production schedules
and therefore overall project economics can be defined (see
Figure 3). The blocks sitting behind the pit shell develop-
ment are populated with parameters relating to the grade
and mineral composition and other key factors. Sorting
amenability and the scale of separation generally do not fit
well with traditional block sizes.
The usual destinations for material mined are combina-
tions of direct plant feed, low grade stockpiles/leaching and
barren waste. There are several complications introduced by
sorting and preconcentration, with the most obvious being:
• Not all ore blocks sent to the plant will be accepted
as feed
• Rejected plant feed may qualify as either low grade
or waste
• Streams split by a sorting process will potentially
report to diverse final geographic locations and
• Accept to reject ratio will potentially vary by indi-
vidual mining block.
Without sorting, the well understood linear progression
from block model to pit shells to schedules and economics
can be quickly and efficiently addressed. If sorting is added
into the mix, it will have a major bearing on total material
movement, plant feed rate, recovery and mass flows to vari-
ous locations. As a consequence, pit shells, schedules and
economic considerations will need to change and therefore,
ensuring sorting is incorporated into the study, at an early
stage, is essential.
Gathering of sorting data requires higher resolution
investigations. In this regard, it is entirely likely that the
input will not be available sufficiently early to be used as an
input into the normal pit design and economic evaluation.
The consequence of such a lag is that it is hard to retrofit
sorting results back into an existing economic evaluation,
particularly if some physical decisions have been hard-
wired into the overall design, i.e., location of processing
plant or waste dumps.
IMPROVED INTEGRATION OF SORTING
AND PRECONCENTRATION INTO
STUDIES
The preconcentration behaviour of an orebody has to be
defined to the same level of confidence as any other pro-
cess step. Such performance definition requires access to
Source: Bearman et al., 2019
Figure 2. Suggested decision support process