3
order to prevent stagnant froth in that area, avoiding design
of too large crowder plate size to prevent pulping effect on
the froth surface, and designing strong crowder structure
with optimized weight to ensure overall load on the tank
does not exceed design criteria.
SPIDER CROWDER UPGRADE JOURNEY
Metso was contacted by a Copper operation looking to
improve froth collection in colossal flotation cells, particu-
larly at the end of the circuit, The Spider Crowder Upgrade
is the result of engineering to adapt drop-in crowders for
TC630 cells. The challenging criteria instituted for develop-
ing a successful solution included: crowding more to tank
perimeter as froth surface area concentrically grows towards
the edges of the tank, avoiding too large crowder plate sizes
to prevent boiling effect on the froth surface, strong struc-
ture with optimized weight to ensure overall load on the
tank does not exceed design criteria, easy installation with
no/minimum modifications to the cell, and having future
service in mind and allowing easy access into the tank for
exchange of mixing mechanism wear parts
Through a comprehensive R&D project the Spider
Crowder design was developed that successfully met all the
criteria mentioned above. The new crowder included:
• Novel crowder design with complex shape for the
outer area of the center launder. This nonsymmetric
shape provides more crowding at the tank perimeter
and less close to the center launder. This resulted in
two different types of spider crowders to cover the
inner and the outer surface of the froth zone.
• Innovative hanger systems to minimize installation
time of the crowders and facilitating easy removal of
them to provide access for maintenance.
SPIDER CROWDER INSTALLATION
The installation of the Spider Crowder Upgrade took place
in early 2023. The installation was designated for penulti-
mate cell of one rougher line. The scope of supply consisted
in 18 Crowders, 6 to be installed in the inner froth zone
and 12 in the outer froth zone.
The retrofit was executed during a planned plant´s shut
down. It was concluded without any safety concerns and
within the estimated mounting time of 24 hours.
The spider crowder impact on the froth zone param-
eters is described in Table 2. As detailed, the new Spider
Crowders decreased upgraded cell´s FSA by 21.2 m2. This
results in a crowding increase from 34.5% to 56.6%. The lip
length was decreased by 14.3 m this is mainly due to spider
crowder being dropped on the center launder and consum-
ing sections of center launder lips where it is hanged on.
Figure 3. Radial froth crowders introduced in Australia,
assembly (left) and individual (right)
Figure 4. Spider Crowder assembly (top) and outer spider
crowder insert (bottom)
order to prevent stagnant froth in that area, avoiding design
of too large crowder plate size to prevent pulping effect on
the froth surface, and designing strong crowder structure
with optimized weight to ensure overall load on the tank
does not exceed design criteria.
SPIDER CROWDER UPGRADE JOURNEY
Metso was contacted by a Copper operation looking to
improve froth collection in colossal flotation cells, particu-
larly at the end of the circuit, The Spider Crowder Upgrade
is the result of engineering to adapt drop-in crowders for
TC630 cells. The challenging criteria instituted for develop-
ing a successful solution included: crowding more to tank
perimeter as froth surface area concentrically grows towards
the edges of the tank, avoiding too large crowder plate sizes
to prevent boiling effect on the froth surface, strong struc-
ture with optimized weight to ensure overall load on the
tank does not exceed design criteria, easy installation with
no/minimum modifications to the cell, and having future
service in mind and allowing easy access into the tank for
exchange of mixing mechanism wear parts
Through a comprehensive R&D project the Spider
Crowder design was developed that successfully met all the
criteria mentioned above. The new crowder included:
• Novel crowder design with complex shape for the
outer area of the center launder. This nonsymmetric
shape provides more crowding at the tank perimeter
and less close to the center launder. This resulted in
two different types of spider crowders to cover the
inner and the outer surface of the froth zone.
• Innovative hanger systems to minimize installation
time of the crowders and facilitating easy removal of
them to provide access for maintenance.
SPIDER CROWDER INSTALLATION
The installation of the Spider Crowder Upgrade took place
in early 2023. The installation was designated for penulti-
mate cell of one rougher line. The scope of supply consisted
in 18 Crowders, 6 to be installed in the inner froth zone
and 12 in the outer froth zone.
The retrofit was executed during a planned plant´s shut
down. It was concluded without any safety concerns and
within the estimated mounting time of 24 hours.
The spider crowder impact on the froth zone param-
eters is described in Table 2. As detailed, the new Spider
Crowders decreased upgraded cell´s FSA by 21.2 m2. This
results in a crowding increase from 34.5% to 56.6%. The lip
length was decreased by 14.3 m this is mainly due to spider
crowder being dropped on the center launder and consum-
ing sections of center launder lips where it is hanged on.
Figure 3. Radial froth crowders introduced in Australia,
assembly (left) and individual (right)
Figure 4. Spider Crowder assembly (top) and outer spider
crowder insert (bottom)