4
example of the importance of paste thickening to produce
stable non segregating depositions that can achieve high
strength and reliable safety within the entire cross section
of the deposit over 13 years of life.
CLEARSTREAM PASTE THICKENER
A paste thickener can be considered the heart of the suc-
cess of the tailings storage. The consistent non-Newtonian
underflow is essential.
The site benefit of stable low-risk tailings storage is
dependent on the feed character, the design and operation
of the paste-type thickener. The feed has some important
character traits, like the particle size distribution that must
be met to even consider a paste or thickened tailings. A Rule
of thumb states that 20% of the weight must be smaller
than 20 microns. The fines particles provide, particularly
the sub-micron size, the ‘bonding’ between the particles
that creates the structure that supports the coarse particles
in a stable paste. This non-Newtonian suspension is char-
acterized by a significant yield stress which is required to
achieve the low-risk storage benefit discussed in this paper.
Success is based on design and operation, there is not
one without the other. Even if the material meets all the
requirements to form a stable non-Newtonian suspension,
if the thickener design is lacking then the desired underflow
will not be achieved regardless of the operating conditions.
The opposite is true for operation of the thickener.
First, the thickener design, particularly the mechanism,
is critical and can be a limiting factor. The thickener objec-
tives of dewatering the feed slurry to the target underflow
(wt% for the target yield stress), then discharge the paste/
thickened tailings underflow are critical and depend on the
design.
Second, the operation of the thickener can easily negate
the careful design of the mechanism. The market is scat-
tered with paste-type thickener installations that are under
performing due to operation. Though a thickener opera-
tion sounds simple adding flocculate to settle the solids for
clear water overflow and discharge the underflow to collect
the solids for downstream use, proper control at prescribed
settings is needed. Sometimes the instincts of the operator
must be changed, contrary to popular opinion, more floc-
culant is rarely the answer (2). ClearStream provides proven
operating control and operating training insuring a produc-
tive start and operation of the paste thickener.
CONCLUSION
The Veragold mine has been an example of attention to
detail, starting with repairing good relations with the sur-
rounding communities. The metallurgical process selected
lowered the risk to the environment and increased recov-
ery. The selection of surface stacking for the tailing stor-
age facility continued with the careful low-risk approach.
Understanding that the paste thickener and the operation
of the thickener is the heart of the tailings management and
selected the ClearStream paste thickener.
REFERENCES
[1] V. Bretas, et al.”Geotechincal and Rheological
Characterization of Bauxite Mining Tailings,” Tailings
2021, 7th International Conference on Tailings
Management.
[2] A. Shaw, Design and Commissioning of the Lisheen
Backfill Plant Paste 2006 R.J. Jewell, et al. (eds), Paste
2006 conference.
example of the importance of paste thickening to produce
stable non segregating depositions that can achieve high
strength and reliable safety within the entire cross section
of the deposit over 13 years of life.
CLEARSTREAM PASTE THICKENER
A paste thickener can be considered the heart of the suc-
cess of the tailings storage. The consistent non-Newtonian
underflow is essential.
The site benefit of stable low-risk tailings storage is
dependent on the feed character, the design and operation
of the paste-type thickener. The feed has some important
character traits, like the particle size distribution that must
be met to even consider a paste or thickened tailings. A Rule
of thumb states that 20% of the weight must be smaller
than 20 microns. The fines particles provide, particularly
the sub-micron size, the ‘bonding’ between the particles
that creates the structure that supports the coarse particles
in a stable paste. This non-Newtonian suspension is char-
acterized by a significant yield stress which is required to
achieve the low-risk storage benefit discussed in this paper.
Success is based on design and operation, there is not
one without the other. Even if the material meets all the
requirements to form a stable non-Newtonian suspension,
if the thickener design is lacking then the desired underflow
will not be achieved regardless of the operating conditions.
The opposite is true for operation of the thickener.
First, the thickener design, particularly the mechanism,
is critical and can be a limiting factor. The thickener objec-
tives of dewatering the feed slurry to the target underflow
(wt% for the target yield stress), then discharge the paste/
thickened tailings underflow are critical and depend on the
design.
Second, the operation of the thickener can easily negate
the careful design of the mechanism. The market is scat-
tered with paste-type thickener installations that are under
performing due to operation. Though a thickener opera-
tion sounds simple adding flocculate to settle the solids for
clear water overflow and discharge the underflow to collect
the solids for downstream use, proper control at prescribed
settings is needed. Sometimes the instincts of the operator
must be changed, contrary to popular opinion, more floc-
culant is rarely the answer (2). ClearStream provides proven
operating control and operating training insuring a produc-
tive start and operation of the paste thickener.
CONCLUSION
The Veragold mine has been an example of attention to
detail, starting with repairing good relations with the sur-
rounding communities. The metallurgical process selected
lowered the risk to the environment and increased recov-
ery. The selection of surface stacking for the tailing stor-
age facility continued with the careful low-risk approach.
Understanding that the paste thickener and the operation
of the thickener is the heart of the tailings management and
selected the ClearStream paste thickener.
REFERENCES
[1] V. Bretas, et al.”Geotechincal and Rheological
Characterization of Bauxite Mining Tailings,” Tailings
2021, 7th International Conference on Tailings
Management.
[2] A. Shaw, Design and Commissioning of the Lisheen
Backfill Plant Paste 2006 R.J. Jewell, et al. (eds), Paste
2006 conference.