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The Impact of Pressure Filter Media Permeability on
Filtrate Suspended Solids
Christopher Olsen, Flavio Santos, Kenneth Rahal
FLSmidth
ABSTRACT: The demand for minerals and metals, especially copper, is growing as the World transitions to
a low-carbon footprint economy. This growth in demand is coinciding with continued declines in ore body
quality. This has forced companies to process larger tonnages to achieve economy of scale which in turn requires
larger amounts of water. This increase in water consumption and tailings generation are also coinciding with
investor pressure for more sustainable mining practices. Pressure is also coming from local communities and
regulators as water scarcity deepens.
To reduce their use of fresh water, mining companies are investigating different tailing solutions that provide
different amounts of recycled water. These alternate options include thickened, paste and filtered tailings. As
part of the investigation into these options, miners want to understand the quality of the water that is being
recycled. There is an expectation that this water may be different from that which is historically recycled from
the tailings impoundment as it has not been exposed to UV nor had time for particles to naturally settle out or
for foreign contaminants (organics, etc.) to entire into the water.
Operators want to understand the difference in quality to determine if it can be reused as is or if it will need fur-
ther treatment prior to being introduced back into upstream processes. This paper will focus on the suspended
solids found in the filtrate of pressure filters. This paper includes laboratory scale pressure filtration testing of
different media with a range of permeabilities. This comparison includes looking at both the difference in sus-
pended solids in the total filtrate collected as well as the change in suspended solids in the filtrate during the
filter cycle. This analysis will include both the quantity and particle size distribution of the suspended solids.
INTRODUCTION
The demand for minerals and metals, especially copper
is growing. As the World Bank’s 2017 report titled “The
Growing Role of Minerals and Metals for a Low-Carbon
Future” shows, demand for metals, including copper, could
rise tenfold by 2050 if the world moves towards a low-car-
bon energy future. This growth in demand is coinciding
with continued declines in ore body quality. Mudd (2009)
showed that ore body grades for copper, lead, zinc and
other minerals have been declining globally. This has forced
companies to process larger tonnages to achieve economy
of scale. These larger throughputs require larger amounts of
water and result in larger amounts of tailings that will have
to be safely stored into perpetuity.
This increase in water consumption and tailings gen-
eration corresponds with investor pressure for more sus-
tainable mining practices (Global Sustainable Investment
Alliance 2018, RBC Global Asset Management 2018).
More mining companies are investigating filtered tailings
The Impact of Pressure Filter Media Permeability on
Filtrate Suspended Solids
Christopher Olsen, Flavio Santos, Kenneth Rahal
FLSmidth
ABSTRACT: The demand for minerals and metals, especially copper, is growing as the World transitions to
a low-carbon footprint economy. This growth in demand is coinciding with continued declines in ore body
quality. This has forced companies to process larger tonnages to achieve economy of scale which in turn requires
larger amounts of water. This increase in water consumption and tailings generation are also coinciding with
investor pressure for more sustainable mining practices. Pressure is also coming from local communities and
regulators as water scarcity deepens.
To reduce their use of fresh water, mining companies are investigating different tailing solutions that provide
different amounts of recycled water. These alternate options include thickened, paste and filtered tailings. As
part of the investigation into these options, miners want to understand the quality of the water that is being
recycled. There is an expectation that this water may be different from that which is historically recycled from
the tailings impoundment as it has not been exposed to UV nor had time for particles to naturally settle out or
for foreign contaminants (organics, etc.) to entire into the water.
Operators want to understand the difference in quality to determine if it can be reused as is or if it will need fur-
ther treatment prior to being introduced back into upstream processes. This paper will focus on the suspended
solids found in the filtrate of pressure filters. This paper includes laboratory scale pressure filtration testing of
different media with a range of permeabilities. This comparison includes looking at both the difference in sus-
pended solids in the total filtrate collected as well as the change in suspended solids in the filtrate during the
filter cycle. This analysis will include both the quantity and particle size distribution of the suspended solids.
INTRODUCTION
The demand for minerals and metals, especially copper
is growing. As the World Bank’s 2017 report titled “The
Growing Role of Minerals and Metals for a Low-Carbon
Future” shows, demand for metals, including copper, could
rise tenfold by 2050 if the world moves towards a low-car-
bon energy future. This growth in demand is coinciding
with continued declines in ore body quality. Mudd (2009)
showed that ore body grades for copper, lead, zinc and
other minerals have been declining globally. This has forced
companies to process larger tonnages to achieve economy
of scale. These larger throughputs require larger amounts of
water and result in larger amounts of tailings that will have
to be safely stored into perpetuity.
This increase in water consumption and tailings gen-
eration corresponds with investor pressure for more sus-
tainable mining practices (Global Sustainable Investment
Alliance 2018, RBC Global Asset Management 2018).
More mining companies are investigating filtered tailings