1
24-084
Testing, Design, Commissioning and Operation—
A Disc Filter Life Experience on a Backfill Plant
Jurgen Hahn
BOKELA GmbH, Karlsruhe, Germany
ABSTRACT
The paper reports on both, the design and decision mak-
ing for the filters in a backfill plant in Europe as well as
more then 10 years of operation and maintenance experi-
ence of the vacuum disc filters installed. It begins with the
first step, the filter sizing based on a sample provided by the
customer, followed by the commissioning of the filter units
and reports on the development of the filter performance
during the following 10 years of operation.
Based on the physical properties of the sample and the
process targets of the client for the backfill plant, the paper
shows the logic steps taken in the laboratory to ensure the
target moisture, determine the required filtration area and
filter size as well as the selection of the ancillary units and
the formulation of the performance guarantee.
The paper discusses some issues with filter operation
during the commissioning phase and the actions taken.
Finally, the paper concludes by highlighting the gradual
change over the more than 10 years of operation and how
this change affected filter performance and operating costs.
INTRODUCTION
The treatment of tailings has become an increasing atten-
tion in the discussion of proper mining operation as well
as the decision-making for new operations. Safety hassards,
environmental risks and a significant consumption of fresh
water are only the main topics to be considered. However,
most, if not all, of these issues are solved, if mine backfill
is used as the solution for tailing treatment and deposit.
Although the main driver for this still expensive solution
is the extra portion of valuable ore to be mined with this
technology and not the safety and well being of the local
communities and the environment. Generally, the earnings
with the extra ore are far more than the extra cost for the
backfill. In any way it requires a proper sizing of the backfill
plant and its major components as well as the flexibility of
these components as the mine operation is expected to last
for decades.
Figure 1 is showing the general design of a backfill
plant.
At the ground level of the building is the positive dis-
placement pump which is feeding the pipeline that goes
to the underground. Above this pump is the mixer which
mixes the filtered solids with cement. The amount of
cement required depends on the mineralogy and the par-
ticle size of the tailing solids. In most cases some water is
added as well to get the right viscosity for pumping. And on
top is the filter which is fed from the tailing thickener with
feed solids typically in the range of 50–65 w/w%. The duty
of the filter is to increase the solids content of the tailings to
a good level for mixing in cement and pumping this slurry
to the underground.
24-084
Testing, Design, Commissioning and Operation—
A Disc Filter Life Experience on a Backfill Plant
Jurgen Hahn
BOKELA GmbH, Karlsruhe, Germany
ABSTRACT
The paper reports on both, the design and decision mak-
ing for the filters in a backfill plant in Europe as well as
more then 10 years of operation and maintenance experi-
ence of the vacuum disc filters installed. It begins with the
first step, the filter sizing based on a sample provided by the
customer, followed by the commissioning of the filter units
and reports on the development of the filter performance
during the following 10 years of operation.
Based on the physical properties of the sample and the
process targets of the client for the backfill plant, the paper
shows the logic steps taken in the laboratory to ensure the
target moisture, determine the required filtration area and
filter size as well as the selection of the ancillary units and
the formulation of the performance guarantee.
The paper discusses some issues with filter operation
during the commissioning phase and the actions taken.
Finally, the paper concludes by highlighting the gradual
change over the more than 10 years of operation and how
this change affected filter performance and operating costs.
INTRODUCTION
The treatment of tailings has become an increasing atten-
tion in the discussion of proper mining operation as well
as the decision-making for new operations. Safety hassards,
environmental risks and a significant consumption of fresh
water are only the main topics to be considered. However,
most, if not all, of these issues are solved, if mine backfill
is used as the solution for tailing treatment and deposit.
Although the main driver for this still expensive solution
is the extra portion of valuable ore to be mined with this
technology and not the safety and well being of the local
communities and the environment. Generally, the earnings
with the extra ore are far more than the extra cost for the
backfill. In any way it requires a proper sizing of the backfill
plant and its major components as well as the flexibility of
these components as the mine operation is expected to last
for decades.
Figure 1 is showing the general design of a backfill
plant.
At the ground level of the building is the positive dis-
placement pump which is feeding the pipeline that goes
to the underground. Above this pump is the mixer which
mixes the filtered solids with cement. The amount of
cement required depends on the mineralogy and the par-
ticle size of the tailing solids. In most cases some water is
added as well to get the right viscosity for pumping. And on
top is the filter which is fed from the tailing thickener with
feed solids typically in the range of 50–65 w/w%. The duty
of the filter is to increase the solids content of the tailings to
a good level for mixing in cement and pumping this slurry
to the underground.