XXXI International Mineral Processing Congress 2024 Proceedings Page 370 (394 of 3836)

392
Benefits of Representative Elemental Analysis of
Conveyed Process Feed Flows
Henry Kurth
Scantech International Pty Ltd
ABSTRACT: Representative, real time multi-elemental analysis of conveyed flows utilizing high performance
Prompt Gamma Neutron Activation Analysis (PGNAA) is well proven in the minerals sector. This paper discusses
successful applications in multiple commodities and potential for further applications to benefit mining and
process operations. Case studies are presented for ore blending, bulk ore sorting, feed forward control and
metal accounting. Additional benefits are available in measuring conveyed flows not currently measured and
also in operational geometallurgy applications, as proxies for process parameters are readily available but under-
utilized. The paper discusses how to minimize risk in selecting and implementing such systems.
INTRODUCTION
Ore quality is predicted from limited data to generate a
block model used as a basis for mine design and extraction
scheduling. Exact tons and grade mined and processed is
difficult to quantify and each measurement process con-
tains errors resulting in discrepancies between planned and
actual metal recovery.
Grade control techniques used in open pit and under-
ground operations determine the destination of mate-
rial extracted from the mine. The expected ore quality is
assessed visually as well as through the use of sensors to
segregate as much ore from waste as possible. This pres-
ents challenges due to the presence of significant quality
variability within each blasted parcel and the limitations of
sensing technologies at this point in the process with most
being only surface analysis techniques. Ore mineralogy and
textures can be complex and surface analysis is rarely able to
provide representative analysis of a batch of material con-
taining large particle size variations, particularly when ore
quality can vary in different size fractions.
Sampling such material according to representative
sampling principles requires a large sample size and much
material handling, size reduction, sub-sampling, and labo-
ratory analysis which all takes time and resources. Assay
results are rarely available in time to make grade control
decisions and consequently ore and waste material is misal-
located to incorrect destinations. Process operators receiv-
ing rock from the mine have limited knowledge of its
heterogeneity or opportunity to influence the quality fur-
ther before processing it.
Techniques do exist that have been successfully imple-
mented to representatively measure conveyed material
quality in real time. This provides an opportunity to further
manage the ore quality before processing. Multi-elemental
analysis of conveyed flows utilizing high performance
Prompt Gamma Neutron Activation Analysis (PGNAA) is
well proven in the minerals sector. Transmission microwave
technology is used to representatively measure conveyed
material moisture content. Magnetic resonance is used to
measure minerals in conveyed material, however, only one
mineral per analyzer.
This paper focusses on successful applications in mul-
tiple commodities of the GEOSCAN high specification
PGNAA system and potential for further applications. Case

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Extracted Text (may have errors)

392
Benefits of Representative Elemental Analysis of
Conveyed Process Feed Flows
Henry Kurth
Scantech International Pty Ltd
ABSTRACT: Representative, real time multi-elemental analysis of conveyed flows utilizing high performance
Prompt Gamma Neutron Activation Analysis (PGNAA) is well proven in the minerals sector. This paper discusses
successful applications in multiple commodities and potential for further applications to benefit mining and
process operations. Case studies are presented for ore blending, bulk ore sorting, feed forward control and
metal accounting. Additional benefits are available in measuring conveyed flows not currently measured and
also in operational geometallurgy applications, as proxies for process parameters are readily available but under-
utilized. The paper discusses how to minimize risk in selecting and implementing such systems.
INTRODUCTION
Ore quality is predicted from limited data to generate a
block model used as a basis for mine design and extraction
scheduling. Exact tons and grade mined and processed is
difficult to quantify and each measurement process con-
tains errors resulting in discrepancies between planned and
actual metal recovery.
Grade control techniques used in open pit and under-
ground operations determine the destination of mate-
rial extracted from the mine. The expected ore quality is
assessed visually as well as through the use of sensors to
segregate as much ore from waste as possible. This pres-
ents challenges due to the presence of significant quality
variability within each blasted parcel and the limitations of
sensing technologies at this point in the process with most
being only surface analysis techniques. Ore mineralogy and
textures can be complex and surface analysis is rarely able to
provide representative analysis of a batch of material con-
taining large particle size variations, particularly when ore
quality can vary in different size fractions.
Sampling such material according to representative
sampling principles requires a large sample size and much
material handling, size reduction, sub-sampling, and labo-
ratory analysis which all takes time and resources. Assay
results are rarely available in time to make grade control
decisions and consequently ore and waste material is misal-
located to incorrect destinations. Process operators receiv-
ing rock from the mine have limited knowledge of its
heterogeneity or opportunity to influence the quality fur-
ther before processing it.
Techniques do exist that have been successfully imple-
mented to representatively measure conveyed material
quality in real time. This provides an opportunity to further
manage the ore quality before processing. Multi-elemental
analysis of conveyed flows utilizing high performance
Prompt Gamma Neutron Activation Analysis (PGNAA) is
well proven in the minerals sector. Transmission microwave
technology is used to representatively measure conveyed
material moisture content. Magnetic resonance is used to
measure minerals in conveyed material, however, only one
mineral per analyzer.
This paper focusses on successful applications in mul-
tiple commodities of the GEOSCAN high specification
PGNAA system and potential for further applications. Case

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391
Innovation and R&D
Sensing and Sorting

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XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 393
studies are presented for ore blending, bulk ore sorting, feed
forward control and metal accounting. Geometallurgical
applications are also discussed but these have yet to be
broadly adopted.
PGNAA TECHNIQUE
Prompt Gamma Neutron Activation Analysis has been
applied to conveyed flows successfully since the 1990s,
mainly in coal and cement (limestone) applications for
quality monitoring and control. In the early 2000s its
application was expanded into the minerals industry when
it was successfully use in iron ore quality measurement. The
application history of PGNAA in the minerals industry has
been discussed in other papers (Kurth 2016).
The PGNAA technique requires a source of neutrons,
a detection system, and suitable software containing a
calibration that processes spectral responses to calculate
composition for a measured timeframe and then transmits
data to a plant control system. The most common neu-
tron source is Californium-252 and detectors are gener-
ally sodium iodide or bismuth germanium oxide (BGO).
The GEOSCAN high specification PGNAA system has its
source located in a heavily shielded section beneath the con-
veyor and the conveyed flow passes through a tunnel where
the zone of neutron flux enables the full width and depth of
material to be exposed to neutrons. Neutrons captured by
elemental nuclei emit gamma energy fingerprints unique to
each element which are detected by an array of high per-
formance BGO detectors configured to maximize spectral
response (Figure 1). The response is accumulated for the
measurement time, such as two minutes (as often as every
thirty seconds or as long as five to ten minutes depending
on application), before an average is determined for each
element and reported in the required format (total by ele-
ment, common oxide form, or mineral, etc.). Any intel-
lectual property (IP) is usually contained in the software,
however, GEOSCAN does have a patented non-contact
design. The GEOSCAN multi-elemental calibration is cus-
tomized to each material to be measured and up to twenty
elements can be simultaneously determined and reported.
Standard load compensation software ensures a tonnage
weighted analysis is determined using a belt weigher input
signal, even when belt load variability exists due to uneven
conveyor feed rates. Flow rates of under 100 tph to over
12,000 tph are currently measured.
PGNAA systems such as the one displayed here provide
representative analysis as they are unaffected by belt speed,
mineralogy, particle size, material segregation, moisture or
dust and measure through the full conveyed profile contin-
uously. Each PGNAA system on the market has differences
in specification: source, detectors, calibration, design, con-
figuration, shielding, customization, installation implica-
tions, measurement capabilities (elements measured, lower
detection limits, precisions, effect of belt type, particle size,
belt load, etc.) which affect their performance and hence
comparisons are sometimes difficult to assess. Few PGNAA
systems have proven successful in mineral applications.
Source: Scantech International Pty Ltd
Figure 1. Cross-section through GEOSCAN high specification PGNAA analyzer showing main
components and an example of elemental results for a two minute measurement increment

Previous Page Next Page

Extracted Text (may have errors)

XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 393
studies are presented for ore blending, bulk ore sorting, feed
forward control and metal accounting. Geometallurgical
applications are also discussed but these have yet to be
broadly adopted.
PGNAA TECHNIQUE
Prompt Gamma Neutron Activation Analysis has been
applied to conveyed flows successfully since the 1990s,
mainly in coal and cement (limestone) applications for
quality monitoring and control. In the early 2000s its
application was expanded into the minerals industry when
it was successfully use in iron ore quality measurement. The
application history of PGNAA in the minerals industry has
been discussed in other papers (Kurth 2016).
The PGNAA technique requires a source of neutrons,
a detection system, and suitable software containing a
calibration that processes spectral responses to calculate
composition for a measured timeframe and then transmits
data to a plant control system. The most common neu-
tron source is Californium-252 and detectors are gener-
ally sodium iodide or bismuth germanium oxide (BGO).
The GEOSCAN high specification PGNAA system has its
source located in a heavily shielded section beneath the con-
veyor and the conveyed flow passes through a tunnel where
the zone of neutron flux enables the full width and depth of
material to be exposed to neutrons. Neutrons captured by
elemental nuclei emit gamma energy fingerprints unique to
each element which are detected by an array of high per-
formance BGO detectors configured to maximize spectral
response (Figure 1). The response is accumulated for the
measurement time, such as two minutes (as often as every
thirty seconds or as long as five to ten minutes depending
on application), before an average is determined for each
element and reported in the required format (total by ele-
ment, common oxide form, or mineral, etc.). Any intel-
lectual property (IP) is usually contained in the software,
however, GEOSCAN does have a patented non-contact
design. The GEOSCAN multi-elemental calibration is cus-
tomized to each material to be measured and up to twenty
elements can be simultaneously determined and reported.
Standard load compensation software ensures a tonnage
weighted analysis is determined using a belt weigher input
signal, even when belt load variability exists due to uneven
conveyor feed rates. Flow rates of under 100 tph to over
12,000 tph are currently measured.
PGNAA systems such as the one displayed here provide
representative analysis as they are unaffected by belt speed,
mineralogy, particle size, material segregation, moisture or
dust and measure through the full conveyed profile contin-
uously. Each PGNAA system on the market has differences
in specification: source, detectors, calibration, design, con-
figuration, shielding, customization, installation implica-
tions, measurement capabilities (elements measured, lower
detection limits, precisions, effect of belt type, particle size,
belt load, etc.) which affect their performance and hence
comparisons are sometimes difficult to assess. Few PGNAA
systems have proven successful in mineral applications.
Source: Scantech International Pty Ltd
Figure 1. Cross-section through GEOSCAN high specification PGNAA analyzer showing main
components and an example of elemental results for a two minute measurement increment

Page 1Plenary Program click to expand contents

Page 22Keynote Presentations click to expand contents

Page 163Innovation and R&D click to expand contents

Page 445Dry Processing click to expand contents

Page 562Water Management click to expand contents

Page 756Human Capital click to expand contents

Page 808Process Control, Modeling, and Simulation click to expand contents

Page 1126Strategic Minerals click to expand contents

Page 1325Geometallurgy and Process Mineralogy click to expand contents

Page 1535Extractive Metallurgy click to expand contents

Page 1842Physical Separations click to expand contents

Page 2016Flotation click to expand contents

Page 3021Energy Minerals click to expand contents

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