Industry-leading turnkey
dirty water clarification solutions

WATER CLARIFIER

The Skelton & Plummer High Rate Clarifier, also known as S&P HRC, offers a complete turnkey dirty water clarification solution that can be utilised both on the surface or underground.

The clarifier was developed for dirty water treatment in gold, platinum and other base metal mines – with the objective of achieving a throughput rate four to six times higher than conventional conical settlers. The requirement for a higher throughput rate became apparent in the mining industry in the eighties, when many settlers, because of increased production, were becoming hydraulically overloaded.

It was often the case that the existing infrastructure could not be extended (by blasting new and/or bigger excavations) to accommodate additional water facilities. The HRC’s popularity is largely due to its throughput rate, of up to six litres per m2 per second, under peak flow conditions.

excellence in execution

S&P HRC Features

Minimal disruption during installation

The S&P HRC can be installed underground or on the surface, depending on the feed arrangements. The smaller shape and dimensions of the clarifier also means that installation can occur with only minor interruptions of the ongoing operations. In cases where it is used in new installations (or extensions or for deepening of shaft systems) it requires only 25 per cent of the surface area of a conventional settler.

Installation – savings of more than 90 per cent

When compared to a conventional settler with the same flow rates, the S&P HRC represents a saving (in excavation volume and related requirements for roof support, linings or similar measures) of more than 90 per cent. The smaller dimensions also result in less rock stresses, which are particularly beneficial for deep mining operations, or areas where bad ground conditions prevail.

Design features

Though the S&P HRC requires the same amount of flocculent as conventional settlers, it achieves overflow clarities of 10 ppm S.S. Due to its unique design features the S&P HRC maintains this quality of overflow water over its full throughput range, from zero to design capacity. The underflow sludge density is comparable to that of conventional settlers.

An additional feature is its capability to collect and trap, in one compartment, contaminants –such as oil, grease, plastics and general debris – that are lighter than water, and which are fed to the clarifier through the dirty water stream.


No moving parts

A further distinctive feature of the S&P HRC is the fact that it has no moving parts. It also accepts any feed fluctuation over the full throughput range without adjustments. The clarifier is user friendly and does not need operator input, it is a completely bolted design, which allows hot dip galvanising of all components. This permits easy transport to the underground installation sites and effortless erection. It also guarantees a long life expectancy at very low maintenance costs.

How it Works

Recycling dirty water for industrial & mining clients

Stefanutti Stocks’ complete dirty water clarification solution consists of four pieces of equipment – the degrit plant, the high rate clarifier (S&P HRC), the automatic gravity sand filter, and the plate and chamber filter press.

The degrit plant, high rate clarifier (S&P HRC), and automatic gravity sand filter have no moving parts to ensure low operational and maintenance costs.

While the equipment combination of each installation is tailored to meet the specific needs of mining and industrial customers, a complete solution will operate as follows:

 

  • Dirty water that needs to be clarified enters the degrit plant, where grit and debris is removed prior to flocculent dosing.
  • It then moves onto the high rate clarifier, where it is separated into clarified water and underflow slurry.
  • Clarified water travels to automatic gravity sand filter where the quality of the overflow water from the high rate clarifier is further improved.
  • The underflow slurry travels to plate and chamber filter press, where the remaining water is extracted.

Case Studies

Thembelani Platinum Mine’s HRC

Specification: Five metre diameter high rate clarifier internals, top support steelwork and dirty water inlet launder with stilling box. Please mouse over the image, for the rationale behind this formation.

Description: Thembelani Platinum Mine’s HRC is located in an underground excavation (a hole was blasted into the footwall), hence there is no external shell to contain the water. The excavation was slyped and shotcrete was applied to form a retaining excavation/dam.

  • The mine had not built a concrete retaining wall (as originally designed) therefore a steel support structure (2) was designed and installed to support the HRC during operation.
    As the HRC now rests on support steelwork, rather than a civil retaining wall, the excavation is in essence a big dam. A grating-panels barricade (3) was added as a safety feature.
  • The mine’s dirty water is piped into the dirty water feed launder (1), where liquid flocculent is added so that the suspended particles flock together, become heavier and to sink to the bottom. The dirty water feed launder discharges into the feed well.
  • The clean water rises to the clear water overflow launders for removal and discharging into the bore hole to be re-used.
  • An access staircase (5) was required for this design, as the clear water overflow launders feed into a bore hole that takes the clean water down to the pump station to be pumped back into the system. An external view of the HRC’s internal parts (6) responsible for agitating the water flow, thereby:
    • allowing solids to settle down to the underflow discharge,
    • turning lighter particles to the flock bed, where they are trapped, and
    • letting the clean water rise to the clearwater overflow launders, for removal and discharge into the bore hole for re-use
1
The mine’s dirty water is piped into the dirty water feed launder (1), where liquid flocculent is added so that the suspended particles flock together, become heavier and to sink to the bottom. The dirty water feed launder discharges into the feed well.
2
The mine had not built a concrete retaining wall (as originally designed) therefore a steel support structure (2) was designed and installed to support the HRC during operation.
3
As the HRC now rests on support steelwork, rather than a civil retaining wall, the excavation is in essence a big dam. A grating-panels barricade (3) was added as a safety feature.
4
Feedwell
5
An access staircase (5) was required for this design, as the clear water overflow launders feed into a bore hole that takes the clean water down to the pump station to be pumped back into the system.
6
An external view of the HRC’s internal parts (6) responsible for agitating the water flow, thereby:
  • allowing solids to settle down to the underflow discharge,
  • turning lighter particles to the flock bed, where they are trapped, and
  • letting the clean water rise to the clearwater overflow launders, for removal and discharge into the bore hole for re-use
  • 1
    The mine’s dirty water is piped into the dirty water feed launder (1), where liquid flocculent is added so that the suspended particles flock together, become heavier and to sink to the bottom. The dirty water feed launder discharges into the feed well.
  • 2
    The mine had not built a concrete retaining wall (as originally designed) therefore a steel support structure (2) was designed and installed to support the HRC during operation.
  • 3
    As the HRC now rests on support steelwork, rather than a civil retaining wall, the excavation is in essence a big dam. A grating-panels barricade (3) was added as a safety feature.
  • 4
    Feedwell
  • 5
    An access staircase (5) was required for this design, as the clear water overflow launders feed into a bore hole that takes the clean water down to the pump station to be pumped back into the system.
  • 6
    An external view of the HRC’s internal parts (6) responsible for agitating the water flow, thereby:
    • allowing solids to settle down to the underflow discharge,
    • turning lighter particles to the flock bed, where they are trapped, and
    • letting the clean water rise to the clearwater overflow launders, for removal and discharge into the bore hole for re-use
Mining Water Clarifier - Skelton & Plummer High Rate Clarifier
1
The dirty water is fed into the dirty water stilling tank (1), from where it is fed through pipes to the degrit plant.
2
The degrit plant (2) consists of sieve bends with wire mesh screens to remove fibrous particles and grit (larger than 2mm) from the dirty water, so as not to clog up the HRC internals.
3
The dirty water is discharged into the dirty water feed launder (3) (10), that feeds the HRCs. As the flow rate of the water exceeds the design capacity of the 6-metre HRC (4), the excess water is diverted to the 7.5-metre HRC (9), to share the load.
4
The dirty water is discharged into the dirty water feed launder (3) (10), that feeds the HRCs. As the flow rate of the water exceeds the design capacity of the 6-metre HRC (4), the excess water is diverted to the 7.5-metre HRC (9), to share the load.
5
Top support steelwork and platform
6
Each HRC has a flocculent dosing plant (6) that doses flocculent based on the flow rate of the water going through the respective HRC. The dosing strength is controlled by a VSD on the pumps to ensure adequate flocculation per HRC and its respective flow rates.
7
Both HRC’s are located in excavations with civil retaining walls, hence only internals were designed. As the heavier particles settle to the underflow discharge (to be pumped away to the mud storage dams), the lighter particles float to the surface to form part of the floc bed. The clean water then flows over into the clear water launders (7) and is fed via the clear water launders to the respective clear water dams for re-use.
7
Both HRC’s are located in excavations with civil retaining walls, hence only internals were designed. As the heavier particles settle to the underflow discharge (to be pumped away to the mud storage dams), the lighter particles float to the surface to form part of the floc bed. The clean water then flows over into the clear water launders (7) and is fed via the clear water launders to the respective clear water dams for re-use.
7
Both HRC’s are located in excavations with civil retaining walls, hence only internals were designed. As the heavier particles settle to the underflow discharge (to be pumped away to the mud storage dams), the lighter particles float to the surface to form part of the floc bed. The clean water then flows over into the clear water launders (7) and is fed via the clear water launders to the respective clear water dams for re-use.
8
Top support steelwork and platform
9
7.5-metre diameter HRC (latest supply)
10
The dirty water is discharged into the dirty water feed launder (3) (10), that feeds the HRCs. As the flow rate of the water exceeds the design capacity of the 6-metre HRC (4), the excess water is diverted to the 7.5-metre HRC (9), to share the load.
  • 1
    The dirty water is fed into the dirty water stilling tank (1), from where it is fed through pipes to the degrit plant.
  • 2
    The degrit plant (2) consists of sieve bends with wire mesh screens to remove fibrous particles and grit (larger than 2mm) from the dirty water, so as not to clog up the HRC internals.
  • 3
    The dirty water is discharged into the dirty water feed launder (3) (10), that feeds the HRCs. As the flow rate of the water exceeds the design capacity of the 6-metre HRC (4), the excess water is diverted to the 7.5-metre HRC (9), to share the load.
  • 4
    The dirty water is discharged into the dirty water feed launder (3) (10), that feeds the HRCs. As the flow rate of the water exceeds the design capacity of the 6-metre HRC (4), the excess water is diverted to the 7.5-metre HRC (9), to share the load.
  • 5
    Top support steelwork and platform
  • 6
    Each HRC has a flocculent dosing plant (6) that doses flocculent based on the flow rate of the water going through the respective HRC. The dosing strength is controlled by a VSD on the pumps to ensure adequate flocculation per HRC and its respective flow rates.
  • 7
    Both HRC’s are located in excavations with civil retaining walls, hence only internals were designed. As the heavier particles settle to the underflow discharge (to be pumped away to the mud storage dams), the lighter particles float to the surface to form part of the floc bed. The clean water then flows over into the clear water launders (7) and is fed via the clear water launders to the respective clear water dams for re-use.
  • 7
    Both HRC’s are located in excavations with civil retaining walls, hence only internals were designed. As the heavier particles settle to the underflow discharge (to be pumped away to the mud storage dams), the lighter particles float to the surface to form part of the floc bed. The clean water then flows over into the clear water launders (7) and is fed via the clear water launders to the respective clear water dams for re-use.
  • 7
    Both HRC’s are located in excavations with civil retaining walls, hence only internals were designed. As the heavier particles settle to the underflow discharge (to be pumped away to the mud storage dams), the lighter particles float to the surface to form part of the floc bed. The clean water then flows over into the clear water launders (7) and is fed via the clear water launders to the respective clear water dams for re-use.
  • 8
    Top support steelwork and platform
  • 9
    7.5-metre diameter HRC (latest supply)
  • 10
    The dirty water is discharged into the dirty water feed launder (3) (10), that feeds the HRCs. As the flow rate of the water exceeds the design capacity of the 6-metre HRC (4), the excess water is diverted to the 7.5-metre HRC (9), to share the load.
Mining Water Clarifier - Skelton & Plummer High Rate Clarifier

Gold One New Kleinfontein Gold Mine

Specification: Two S&P HRC (one 6,0 metre diameter, and one 7,5 metre diameter) internals, top support steelwork, clearwater overflow launders to clearwater dams and flocculent dosing plant. Please mouse over the image, for the rationale behind this formation.

A degrit plant complete with two 2155mm duty screens, a stilling box, dirty water launders to High Rate Clarifiers and conveyor for grit discharge.

Description: Two S&P HRCs were installed at the Gold One New Kleinfontein Gold Mine. As New Kleinfontein is in development the water-flow rates will change during the life of the mine, therefore two clarifiers were designed. The 6-metre diameter HRC will handle the initial dirty water, with the second 7.5-metre diameter HRC handling additional mine water requirements.

 

  • The dirty water is fed into the dirty water stilling tank (1), from where it is fed through pipes to the degrit plant.
  • The degrit plant (2) consists of sieve bends with wire mesh screens to remove fibrous particles and grit (larger than 2mm) from the dirty water, so as not to clog up the HRC internals.
  • The dirty water is discharged into the dirty water feed launder (3) (10), that feeds the HRCs. As the flow rate of the water exceeds the design capacity of the 6-metre HRC (4), the excess water is diverted to the 7.5-metre HRC (9), to share the load.
  • Each HRC has a flocculent dosing plant (6) that doses flocculent based on the flow rate of the water going through the respective HRC. The dosing strength is controlled by a VSD on the pumps to ensure adequate flocculation per HRC and its respective flow rates.
  • Both HRC’s are located in excavations with civil retaining walls, hence only internals were designed. As the heavier particles settle to the underflow discharge (to be pumped away to the mud storage dams), the lighter particles float to the surface to form part of the floc bed. The clean water then flows over into the clear water launders (7) and is fed via the clear water launders to the respective clear water dams for re-use

Impala 20 Shaft

Specification: Two 6,5 metre diameter high rate clarifier internals with external shell, Top support steelwork, dirty water inlet launders and mud storage tanks.

Description: The Impala 20 Shaft installation allows for two 6.5-metre freestanding HRCs located in excavations, with the off-vent shaft HRC situated directly above a clear water dam.

The off-vent shaft HRC therefore sits on a support structure over the dam, within the excavation in the footwall, while the vent shaft HRC is located in a vent shaft on a support platform.

Both units are fed from a single launder where the inlet flow can be diverted to either launder (one duty and one standby). Alternatively flow can be throttled to let both units run at the same time, should flow rates require this.

As per the clients requirements, the clear water is gravity-fed to the clear water dams below, the mud is sucked out of the HRC external shell during the drawdown cycle and then pumped to the mud storage tanks, from where it is sent to a filter press to be de-watered for easier removal on the conveyors.

1
Access platform
2
Off vent shaft HRC - freestanding unit
3
Dirty water feed launder
4
Support platform
5
Mud storage tanks
6
Access cat ladder
7
Vent shaft HRC - freestanding unit
8
External shell
9
Shell support steelwork
  • 1
    Access platform
  • 2
    Off vent shaft HRC - freestanding unit
  • 3
    Dirty water feed launder
  • 4
    Support platform
  • 5
    Mud storage tanks
  • 6
    Access cat ladder
  • 7
    Vent shaft HRC - freestanding unit
  • 8
    External shell
  • 9
    Shell support steelwork
Mining Water Clarifier - Skelton & Plummer High Rate Clarifier