440 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
there is still room to improve mill operational stability and
optimization by knowing in greater detail what is com-
ing to the mill and when it will arrive. This detail comes
in the form of smaller lots of material and shorter dura-
tions of time. Process control systems offer the ability to
react quickly to changes when they occur. Along with these
initiatives another goal is to better control what the mine
delivers to the mill over shorter time intervals. To this end,
there is a recognized need to better understand what the
mine is producing and what is being delivered to the mill.
Thus, the interest in sensors to monitor stockpile and mill
feed in real time. This information provides value in the
form of feedback to the mining operation of the quality
of the material mined and delivered beyond just the tra-
ditional KPIs of tonnage mined and a grade control assay.
As the more readily accessible and treatable ore bod-
ies have been exploited in earlier decades, today’s mineral
processors are faced with treating more complex ore bodies.
Complexity comes in a variety of forms, greater variabil-
ity in pay metal and gangue mineralogy as well as spatial
variation in grade, hardness and ore types. This variabil-
ity poses challenges for plant operations and metallurgical
teams. Sudden and unexpected changes in mineralogy can
cause efficiency loss in the unit operations used to process
the ore. Instability of operation puts the operations in a
reactive mode to catch up with the ore changes instead of
operating from a stable state in which optimization of the
different processing steps can be achieved. Therefore, there
is interest in reduction in stockpile and mill feed variability
through adoption of technology and sensors such as over
the belt analyzers.
Beyond the lack of uniformity in the ore body, other
sources of variability arise from the mining methods and
operational strategies, routing mistakes, and unplanned
equipment downtime. This can lead to unexpected material
entering the mill and may first be experienced as changes of
grindability, mill product size and throughput. In the sub-
sequent separation process, feed rate, particle size, %solids,
reagent addition, aeration rates and cell levels may all need
to be adjusted to accommodate changes in the incoming
ore. Stabilization of feed characteristics simplifies the plant
operator’s job and allows time for optimization of these con-
trol parameters to maximize the metallurgical performance.
In 2019, Thermo Fisher Scientific was approached by
Newcrest Mining, now Newmont, who had previously
installed two PGNAA analyzers at two of their operations.
They were interested in understanding Thermo Fisher’s
PGNAA technology and deploying an analyzer at their
Red Chris mine in British Columbia, Canada. An agree-
ment was reached in 2021 to conduct a 6-month trial of
a Thermo Scientific CB Omni analyzer, with an option to
acquire the analyzer upon a successful trial outcome.
Thermo Fisher Scientific’s approach to calibration has
significant benefits to the ease and speed of startup and
end-users realizing the benefits of PGNAA. The first stage
of the project required establishing the elemental ranges
and understanding the operating belt loading ranges so that
a full factory calibration can be done to meet the applica-
tion’s measurement requirements. Red Chis requested plant
samples be measured in the factory in addition to the cali-
bration reference standards.
Providing site specific samples can reduce risk for the
end-user, as they want to validate a measurement technol-
ogy’s capability with their material. However, obtaining a
suite of samples that have sufficient range of all elements
necessary for developing a robust calibration to account
for the full range of expected chemistry, is often unfeasi-
ble. A preferential approach is to manufacture calibration
reference standards that span the expected full elemental
ranges, as component ingredients can be selected to suit
the application and ensure a more reliable analysis over the
long term.
RESULTS
The above approach was used to calibrate the CB Omni
analyzer deployed for the 6-month trial at Red Chris.
Figure 1 shows the measured Cu and S results of both the
calibration reference standards and Red Chris’ samples dur-
ing the factory calibration. The graphs in Figure 1 highlight
the narrower ranges of Cu and S in the Red Chris samples
compared to the calibration reference standards.
In addition to the primary copper sulfide chemistry,
ensuring the calibration spans the full the gangue chemistry
is also critical. Again, it is unfeasible to obtain sufficient
range with end-user supplied samples to ensure a successful
calibration. Figure 2 shows the measured results of both the
calibration reference standards and customer samples dur-
ing the factory calibration for the major gangue elements.
It is not only critical to ensure a comprehensive factory
calibration process spans the expected elemental chemistry
ranges, but also the expected variation in material loading
on the belt under normal operating conditions. Thermo
Fisher’s proprietary automatic belt load calibration process
ensures that measurement accuracy is maintained during
normal operation, where material flow conditions will
inevitably be variable. The modular design of the reference
standards enables measurement of the standards at differ-
ent kg/m loadings that span the expected range during
operation.
there is still room to improve mill operational stability and
optimization by knowing in greater detail what is com-
ing to the mill and when it will arrive. This detail comes
in the form of smaller lots of material and shorter dura-
tions of time. Process control systems offer the ability to
react quickly to changes when they occur. Along with these
initiatives another goal is to better control what the mine
delivers to the mill over shorter time intervals. To this end,
there is a recognized need to better understand what the
mine is producing and what is being delivered to the mill.
Thus, the interest in sensors to monitor stockpile and mill
feed in real time. This information provides value in the
form of feedback to the mining operation of the quality
of the material mined and delivered beyond just the tra-
ditional KPIs of tonnage mined and a grade control assay.
As the more readily accessible and treatable ore bod-
ies have been exploited in earlier decades, today’s mineral
processors are faced with treating more complex ore bodies.
Complexity comes in a variety of forms, greater variabil-
ity in pay metal and gangue mineralogy as well as spatial
variation in grade, hardness and ore types. This variabil-
ity poses challenges for plant operations and metallurgical
teams. Sudden and unexpected changes in mineralogy can
cause efficiency loss in the unit operations used to process
the ore. Instability of operation puts the operations in a
reactive mode to catch up with the ore changes instead of
operating from a stable state in which optimization of the
different processing steps can be achieved. Therefore, there
is interest in reduction in stockpile and mill feed variability
through adoption of technology and sensors such as over
the belt analyzers.
Beyond the lack of uniformity in the ore body, other
sources of variability arise from the mining methods and
operational strategies, routing mistakes, and unplanned
equipment downtime. This can lead to unexpected material
entering the mill and may first be experienced as changes of
grindability, mill product size and throughput. In the sub-
sequent separation process, feed rate, particle size, %solids,
reagent addition, aeration rates and cell levels may all need
to be adjusted to accommodate changes in the incoming
ore. Stabilization of feed characteristics simplifies the plant
operator’s job and allows time for optimization of these con-
trol parameters to maximize the metallurgical performance.
In 2019, Thermo Fisher Scientific was approached by
Newcrest Mining, now Newmont, who had previously
installed two PGNAA analyzers at two of their operations.
They were interested in understanding Thermo Fisher’s
PGNAA technology and deploying an analyzer at their
Red Chris mine in British Columbia, Canada. An agree-
ment was reached in 2021 to conduct a 6-month trial of
a Thermo Scientific CB Omni analyzer, with an option to
acquire the analyzer upon a successful trial outcome.
Thermo Fisher Scientific’s approach to calibration has
significant benefits to the ease and speed of startup and
end-users realizing the benefits of PGNAA. The first stage
of the project required establishing the elemental ranges
and understanding the operating belt loading ranges so that
a full factory calibration can be done to meet the applica-
tion’s measurement requirements. Red Chis requested plant
samples be measured in the factory in addition to the cali-
bration reference standards.
Providing site specific samples can reduce risk for the
end-user, as they want to validate a measurement technol-
ogy’s capability with their material. However, obtaining a
suite of samples that have sufficient range of all elements
necessary for developing a robust calibration to account
for the full range of expected chemistry, is often unfeasi-
ble. A preferential approach is to manufacture calibration
reference standards that span the expected full elemental
ranges, as component ingredients can be selected to suit
the application and ensure a more reliable analysis over the
long term.
RESULTS
The above approach was used to calibrate the CB Omni
analyzer deployed for the 6-month trial at Red Chris.
Figure 1 shows the measured Cu and S results of both the
calibration reference standards and Red Chris’ samples dur-
ing the factory calibration. The graphs in Figure 1 highlight
the narrower ranges of Cu and S in the Red Chris samples
compared to the calibration reference standards.
In addition to the primary copper sulfide chemistry,
ensuring the calibration spans the full the gangue chemistry
is also critical. Again, it is unfeasible to obtain sufficient
range with end-user supplied samples to ensure a successful
calibration. Figure 2 shows the measured results of both the
calibration reference standards and customer samples dur-
ing the factory calibration for the major gangue elements.
It is not only critical to ensure a comprehensive factory
calibration process spans the expected elemental chemistry
ranges, but also the expected variation in material loading
on the belt under normal operating conditions. Thermo
Fisher’s proprietary automatic belt load calibration process
ensures that measurement accuracy is maintained during
normal operation, where material flow conditions will
inevitably be variable. The modular design of the reference
standards enables measurement of the standards at differ-
ent kg/m loadings that span the expected range during
operation.