Veolia stays on-site to reduce costs for Evander Gold Mine
24 april 2015
Veolia embarked on this total water management agreement in November last year following a full site survey on Pan African Resources, Evander Gold Mining PTY Ltd MET Plant as well as 7 and 8 shaft. This survey revealed that large parts of the water circuits were not being treated by any chemicals due to faulty dosing stations while other parts of the circuits were facing dangerous chemical spillages where dosing station pumps had broken. As a result, highly corrosive water and scale were flowing through the above and below ground water circuits, decreasing the mine’s cooling and ventilation efficiency while damaging its equipment. “We opted for a full operation and maintenance agreement with Evander Gold Mine, where we will manage the entire water treatment system. As part of the agreement, a Veolia specialist will remain on-site for the duration of the contract, providing 24/7 technical direction, support and consultancy,”
says Carl van Heerden, Hydrex Industrial Manager, Veolia Water Technologies South Africa.
As part of this agreement, Veolia supplied 12 new treatment solutions, including: new chemical dosing stations; flocculants, coagulants, anti-scalant and micro-biocide chemical treatment; a semi-automated duplex flocculent plant; and coagulant plants to address the water treatment problems. Veolia also supplied its range of Hydrex™ chemicals at a variable fee after a weekly stock-take – meaning the mine will ultimately only pay for chemicals it has used.
Since the revised treatment plan was implemented, Junior Sales Consultant Pieter Jacobs, together with van Heerden, have managed and monitored the mine’s water treatment progress through weekly water analyses and reports. Results recently detailed in the four-month review of the programme show that the new treatment regime is not only out-performing compared to specification; it is also saving the mine money through a much more efficient operation.
Due to the bad state of the circuit’s settlers at shaft 8, Veolia commenced treatment using gel blocks and added a Hydrex™ 3936 coagulant. This dual treatment programme saw immediate positive results: the turbidity and Total Suspended Solids (TSS) levels were reduced by 45% on settler 1 and 37% on settler 2. Furthermore, the duplex flocculent and coagulant plants have resulted in a further turbidity reduction of 27% on settler 1 and 48% on settler 2 allowing for proper dosing control while optimising the treatment programme. In addition, all old non-functional dosing stations at the fridge plant were replaced with new dosing stations, drastically improving iron and Total Dissolved Solids (TDS) concentrations.
At shaft 7, Veolia installed a new coagulant dosing station that employs a custom-designed chemical treatment programme consisting of Hydrex™ 6611 and Hydrex™ 3936. This new treatment programme has resulted in a reduction of turbidity levels of 32% and overall settler efficiency improvement from 90% to 98%. Two new dosing stations were also installed along with the condenser, main compressor cooling tower and spray pond. These stations utilised Hydrex™ 2204 and Hydrex™ 7761 chemicals, which again improved the overall iron and TDS concentrations as well as a visible reduction of algae. “The improvement of the water quality on the settlers benefits the entire water circuit. Overall TDS and iron concentrations are down, the circuits require fewer chemicals each month and the equipment gets closer to spec – ultimately running more efficiently and lowering overall maintenance costs,”
comments van Heerden. “We also worked around the clock, 7 days-a-week to install new equipment in just 30 days – half the expected time – and installation was relatively seamless considering we were adding and removing equipment so far below ground”.
Owing to the early success of this agreement, Veolia is currently in negotiations with Evander Gold Mining PTY Ltd to expand its outsourced agreements locally as well as within Pan African Resources’ other mines throughout southern Africa.
------Caption Picture 1: Veolia installed spill-proof and accurate chemical dosing stations around the mine.
Caption Picture 2: Veolia designed and installed 12 new treatment stations situated above ground and 1.8 kilometres below ground that increased the mines’ overall efficiency.
group is the global leader in optimized resource management. With over 179,000 employees* worldwide, the Group designs and provides water, waste and energy management solutions that contribute to the sustainable development of communities and industries. Through its three complementary business activities, Veolia helps to develop access to resources, preserve available resources, and to replenish them.
In 2014, the Veolia group supplied 96 million people with drinking water and 60 million people with wastewater service, produced 52 million megawatt hours of energy and converted 31 million metric tons of waste into new materials and energy. Veolia Environnement (listed on Paris Euronext: VIE)
recorded consolidated revenue of €24.4 billion* in 2014.www.veolia.com(*) 2014 pro-forma figures, including Dalkia International (100%) and excluding Dalkia France.
ContactsCarl van Heerden
Hydrex Industrial ManagerVeolia Water Technologies South Africa
Off.: + 27 (0) 11 974 email@example.com