3
effects and therefore must be controlled. Seepage control
measures range from installing design controls like liners,
drains and collection ponds to water treatment systems
allowing water disposal to the environment. The costs
related to the implementation of these measures are largely
dependent on the total volume of seepage. This implies that
the cost incurred in seepage treatment can be considered as
an indirect cost of freshwater intake. When water is not lost
to the environment, it will not require treatment or replen-
ishment. The indirect costs of water intake are therefore:
• Ground water treatment as remediation of seepage-
induced contamination of aquifers.
• Seepage control measures like liners, drains and
treatment systems.
The collated cost of freshwater intake is the sum of direct
and indirect costs. The primary focus should always be on
minimising the volume of contaminated water and clean
water diversion to minimise the propensity to generate con-
taminated water (Atkinson et all., 2013).
The direct costs of freshwater intake are driven by flow
velocity, pipe diameter, pipeline route, pumping efficiency
and water quality. In general, pumping water from a TSF
to the process plant costs up to $0.35 per cubic meter. The
indirect costs of water treatment vary based on the type and
level of contamination, as well as discharge limitations. For
this study, the work of Keir et al. has been used as a refer-
ence for indirect costs. Keir indicates that the operational
costs of a treatment system are between $0.90 and $1.60
per cubic meter (Keir, 2013). Reverse osmosis can require
up to 1 kWh/m3 in energy consumption (Atkinson et al.,
2013). Considering the large volumes handled in tailings
management, a reduction of this requirement will have a
direct effect on both operational costs and emissions.
THE OPERATION
This study considers an iron ore mining operation in the
Northern United States that has been operational for sev-
eral decades. It operates a Tailings Storage Facility (TSF)
located 12.5 kilometers from the processing plant. The
dilute fine tailings are thickened to 32% solids concentra-
tion by weight and pumped to the TSF for disposal using
a single pipeline. The pipeline includes two pump stations,
each equipped with a centrifugal pump train (three pumps
in series for the first pumpstation and four in series for the
second pumpstation).
The current pumping layout has reached maximum
capacity hence a review of the pumping strategy was
launched. The addition of an extra stage to the second
pumpstation would be the conventional approach. The
customer’s ambition to reduce their emissions led them to
consider an alternative tailings handling strategy. Changing
to PD pumping technology was considered to reduce emis-
sions by approximately 20% because of its higher efficiency.
In this case study the upgrade of the tailings handling sys-
tem is assessed for feasibility considering the investment is
paid for by the savings in energy, water and carbon costs.
The current tailings handling system is presented in
Figure 1. The system consists of a single pipeline that is
serviced by two pump stations. Pump station 1 is operat-
ing at a pressure of approximately 20 bar and pump sta-
tion 2 between 45 and 50 bar depending on the location of
Figure 1. Topography and Hydraulic Grade Line (HGL) of the existing pipeline
effects and therefore must be controlled. Seepage control
measures range from installing design controls like liners,
drains and collection ponds to water treatment systems
allowing water disposal to the environment. The costs
related to the implementation of these measures are largely
dependent on the total volume of seepage. This implies that
the cost incurred in seepage treatment can be considered as
an indirect cost of freshwater intake. When water is not lost
to the environment, it will not require treatment or replen-
ishment. The indirect costs of water intake are therefore:
• Ground water treatment as remediation of seepage-
induced contamination of aquifers.
• Seepage control measures like liners, drains and
treatment systems.
The collated cost of freshwater intake is the sum of direct
and indirect costs. The primary focus should always be on
minimising the volume of contaminated water and clean
water diversion to minimise the propensity to generate con-
taminated water (Atkinson et all., 2013).
The direct costs of freshwater intake are driven by flow
velocity, pipe diameter, pipeline route, pumping efficiency
and water quality. In general, pumping water from a TSF
to the process plant costs up to $0.35 per cubic meter. The
indirect costs of water treatment vary based on the type and
level of contamination, as well as discharge limitations. For
this study, the work of Keir et al. has been used as a refer-
ence for indirect costs. Keir indicates that the operational
costs of a treatment system are between $0.90 and $1.60
per cubic meter (Keir, 2013). Reverse osmosis can require
up to 1 kWh/m3 in energy consumption (Atkinson et al.,
2013). Considering the large volumes handled in tailings
management, a reduction of this requirement will have a
direct effect on both operational costs and emissions.
THE OPERATION
This study considers an iron ore mining operation in the
Northern United States that has been operational for sev-
eral decades. It operates a Tailings Storage Facility (TSF)
located 12.5 kilometers from the processing plant. The
dilute fine tailings are thickened to 32% solids concentra-
tion by weight and pumped to the TSF for disposal using
a single pipeline. The pipeline includes two pump stations,
each equipped with a centrifugal pump train (three pumps
in series for the first pumpstation and four in series for the
second pumpstation).
The current pumping layout has reached maximum
capacity hence a review of the pumping strategy was
launched. The addition of an extra stage to the second
pumpstation would be the conventional approach. The
customer’s ambition to reduce their emissions led them to
consider an alternative tailings handling strategy. Changing
to PD pumping technology was considered to reduce emis-
sions by approximately 20% because of its higher efficiency.
In this case study the upgrade of the tailings handling sys-
tem is assessed for feasibility considering the investment is
paid for by the savings in energy, water and carbon costs.
The current tailings handling system is presented in
Figure 1. The system consists of a single pipeline that is
serviced by two pump stations. Pump station 1 is operat-
ing at a pressure of approximately 20 bar and pump sta-
tion 2 between 45 and 50 bar depending on the location of
Figure 1. Topography and Hydraulic Grade Line (HGL) of the existing pipeline