+27 (0) 11 820 4600 | S&Pclarifier@stefstocks.com

S&P Clarifier

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about the S&P HRC


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.

This patented high rate clarifier is available

from Stefanutti Stocks Mechanical at

+27 (11) 820 4600 or


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.