WATER MANAGEMENT
Paul Moore spoke to David Oliphant , Vice President Business Development - Heavy Industry at Veolia Water Technologies Canada for his take on mine water management plus the rise of mobile solutions
Q As a specialist water solutions company are you seeing mining companies becoming more serious about implementing water treatment and water management at an early planning stage , despite the added investment costs ? A Mining companies are definitely much more serious about implementing water treatment . Without implementing a robust treatment strategy , mining companies can often find long delays in permitting if regulators are not in agreement with their approach . More and more water treatment systems are one of the major upfront activities that must happen early on in the project development cycle . It really comes down to social licence to operate .
Q Is the greater focus on getting water management right being driven by water shortages , a more sustainable mining culture , local community pressures or all of these ? A We see more early focus on water treatment in mine planning . In our opinion there are two main drivers for this :
Regulatory requirements . The mine permitting is often on the critical path , and you nowadays cannot get permitting without a detailed plan for water treatment . The regulators have become more aware of the necessity of this , and are also becoming more weary of being strung along by less scrupulous operators . The level of detail required for permitting has increased significantly compared to what it was only ten years ago , and we see the difference in our day to day job .
Community acceptance . It has become almost impossible to start a new mine without community acceptance . In locations where mining has historically been present this is easier to get , but in locations without this mining history this may be difficult . In order to get this acceptance , it is essential to engage in a dialogue with the local stakeholders , listen to their concerns and come up with a good plan on how to address them . Water will usually be one of the main concerns here .
Veolia Water Technologies mobile Actiflo unit
Q What about long established operations – are more and more operators looking to “ retrofit ” water treatment into mining complexes despite limited remaining mine life ? A Like any business , mining is there to make money , so there is always a cost vs benefit analysis done before a big investment . Big investments at the end of mine life are not usual as mines are usually regulated based on a permit issued at mine start . If this becomes necessary then the mining clients will have to decide whether to invest in the treatment or close the mine . In cases where mining clients need to upgrade the performance of an existing facility , Veolia can often be involved in supplementing existing facilities with Mobile Water Services . In such a case , Veolia can dispatch mobile assets to assist in meeting regulatory requirements . End of mine life often plays a role in such decisions .
Q Can you give any real project examples of mobile solutions ? A Veolia Water Technologies provided two 100 m3 / h nano-filtration units through its Mobile Water Services rental fleet for a nickel mine located in a very remote area of Canada . The mine site needed to remove thiosalts from its wastewater in order to ensure the site could meet their permit limits for discharging wastewater back into the environment . Due to the very remote location of the mine site , the client needed an expedited water treatment solution since the site is only accessible a few months each year . Veolia was able to expedite the supply of the mobile units in order to meet the client ’ s limited delivery time frame due to the remote site location and very harsh climate . The compact and efficient design of the units were able to easily integrate into the facility ’ s existing wastewater treatment process at the site . lower-centre feed eye design which optimises filtration rates , resulting in the industry ' s lowest product moisture per kW . “ The AFP2525 ' s heavyduty design , high efficiency flood wash and offfilter cloth changing system produce high availability . Fast filtration rates and short mechanical times minimise the filter cycle time . The combination of speed and reliability result in the lowest cost per tonne in the industry .” Wisdom adds that as many mines are approaching the end of life of their current tailings storage facilities ( TSF ), many mines are evaluating how to extend their life economically . Not only can filtered tailings increase the life of a current TSF you can potentially use the filtered tailings to increase TSF embankment heights . “ There is also an opportunity to reprocess old slurry tailings facilities that have value in their tailings . Several companies are looking at this reprocessing to generate revenue , of which just a portion of the revenue can then be used to filter the reprocessed tailings and make a more stable and safe TSF .”
Metso Outotec ’ s Jason Palmer , VP , Tailings and Water comments : “ There is considerable interest in filtered tailings and the option is being evaluated in most new projects and many existing operations where the tailings storage facility is nearing its end of life . To date there seems to be more interest converted to action from small to medium mining companies than large multinationals . Even these smaller projects require large tonnage filters and there are economies of scale with the larger units increasing the attractiveness of filtered tailings options .”
What about the water saving upside with large filters ? Wisdom told IM : “ In arid regions and where water is pumped to high altitudes , like in Peru and Chile , the cost of water can be very expensive . I have seen water costs higher than $ 5 / m 3 in those areas . At water costs above $ 3 / m 3 a complete tailings filtration plant including equipment , installation , buildings , conveyors , and automated stacking systems start to break even with lower performance dewatering technologies . So , in those areas , changing to a filtered tailings system can make economic sense as well as social and environmental sense .”
Palmer commented : “ Dry stacking filtered tailings does save water and there can be 0.2 m 3 / t water savings between thickened tailings and filtered tailings options . However , these savings seldom mitigate the additional capital required for filtered tailings as in most cases water is still very inexpensive . Arid regions do have greater water drivers but the interest is not limited to arid regions and even sites with high rainfall are interested in filtered tailings . Water availability and tailings storage risk seem to be more important drivers than water cost . Even in cases where the lifetime costs are similar filtered tails are capital intensive at the front end and tailings dams are expensive at closure far in the future , so capital availability is a significant
46 International Mining | MARCH 2021