Environmental engineering consultancy African Horizon Technologies has sold a Hydraspin oil-water separator to mining major Glencore’s Thorncliff mine, in Steelpoort, Limpopo, to use in one of its workshops.
African Horizon Technologies is waiting for the civil works to be completed before it can install the separator on site either this month or the next, says African Horizon Technologies MD Jacques Steyn.
“Hydraspin or hydro cyclone separators are used to remove oil from water, Hydraspin uses centrifugal forces 3 000 times the force of gravity to remove oil from water. Typically, these separators are installed on all the wash bays, workshops, diesel bays and diesel fuel-dispensing sites, prohibiting the diesel in lubricants from contaminating the mines’ water.”
Using the separators and other African Horizon Technologies innovations on site, where the pollution occurs, enables mines to remove the oil at the source, so there is limited downstream pollution from mines, he adds.
Steyn describes the outcome of this offering as “successful in the local mining sector”, with treatment systems currently in use all over Africa in different locations and applications.
In addition, African Horizon Technologies also encourages mines to actively and sustainably reuse water by offering an electro-coagulation ‘Hydramix’ system that removes suspended solids, heavy metals, emulsified oils, bacteria and other contaminants from water.
Further, Steyn says that mines can use water efficiently by implementing low life-cycle technologies. Several technologies are available to solve the looming water crisis.
“There are more sustainable ways of treating water and we, as African Horizon Technologies, are involved in products and technologies which we know have low life-cycle-cost consequences for mines.”
He explains that, by using or acquiring these technologies, mines will have a capital expenditure for equipment upfront, while the operational cost of the technology is virtually zero.
“That, in my view, is the most sustainable way for a mine to treat process water,” he says.
Steyn adds that, as low life-cycle technology is a concept that is misunderstood by management in the mining industry, mines often opt to buy products that have operational costs on a day-to-day basis.
Such products include filters and chemicals being transported, dosed and managed at a mine site, which can be costly.
Steyn also highlights a lack of enthusiasm and respect with regard to water treatment in South Africa.
He says water quality in South Africa has drastically declined over the years because government does not enforce the National Water Act, while industry does not adhere to it.
Steyn tells Mining Weekly that there are water treatment processes that often use membrane technology, such as reverse osmosis (RO), which has a negative impact on the environment. The life cycle costs of these technologies are high and the impacts far-reaching.
“Mines don’t realise that the yield of a RO plant is anything between 30% and 50%. This means that 50% of 100 000 ℓ of water will become wastewater, which a mine needs to do something about. In salt water desalination applications, the yield can decrease to 30%.
“In addition, if there are heavy metals and salts in the water concentrating into waste, every hour that goes by will result in the mine having an increased wastewater problem,” he explains.
Removing suspended solids from mine water is very important and methods such as microscreen and electro-coagulation or a chemical treatment process are used to create a chemical reaction while separating the heavy metal from the water. These methods are the mainstream applications for removing heavy metal.
The removal of heavy metals from mine water is important because it will have an impact on water quality, depending on the type of solid. If it is a heavy metal, the mine will have heavy metal contamination in its water.
“If it is organic material, mines will have to deal with other biological impacts, such as chemical oxygen. This means that there is less oxygen in the water, making it toxic. By removing solids, you are going a long way towards creating better water quality.
“Solids removal and the removal of heavy metals are different processes that can be combined. Heavy metals are dissolved in water most of the time, which is a different problem altogether. Low acid conditions result in heavy metals dissolving in the water, which is why acid mine drainage is such a great concern,” he says.
More attention should be given to water treatment in the mining industry and other industries. Measures, such as the monitoring and collecting of data from water samples, will assist in acquiring results in real time to improve the water quality, explains Steyn.
Based on the results and the various technologies available, improved water quality can be achieved. However, this will require a change in mindset from the mining industry and government, he concludes.