WATER MANAGEMENT & TREATMENT
Warman ® DWU 75 single-stage high-pressure pump , ensuring uninterrupted mining production in an underground operation
at all , to maintain proper settling to produce clean water . “ As a result , the clean water pumps end up pumping dirty water before long and , inevitably , wear the pumps out much faster than originally anticipated . This then leads to unplanned downtime and increased operating costs , as well as the need to carry higher inventory to , in a sense , plan around the unplanned downtime .”
Furthermore , the settling solids – which is
essentially a waste product – has to be brought to the surface ; this is typically done via the production skip , which is an inefficient system that ’ s more energy intensive and less sustainable than pumping the solids to the surface .
He continues : “ Mine operators want to focus their resources on driving production . Maintaining settling sumps means resources need to be reallocated away from production to keep the clean water pumping system operating reliably . Therefore , this loss of production cost needs to also be considered when choosing the type of dewatering system . Since most operations have already mined the easily accessible ore , existing mines are now going deeper to access the ore bodies . And ore bodies that were once too deep or too expensive to access are today ’ s greenfield or brownfield expansion projects . This means that underground dewatering systems typically require higher pressures than they did previously .”
Weir Minerals ’ Warman ® DWU pump is able to handle dirty water with 10 % w / w solids concentration , with high peaks during temporary upset conditions up to 20 % w / w concentration . It is designed with a casing pressure rated at 700 kPa ( 1,000 psi ), which means it ’ s well suited to these high pressure underground dewatering applications . At maximum operating speed , the Warman ® DWU pumps can individually achieve heads of approximately 140 m at the best efficiency point . However , due to the high casing pressure design , and when combined with the correct pump sealing selection , the pumps can be configured in an in-series solution to achieve discharge pressures of up to 55 bar .
Weir says it has multiple pump sizes within its Warman ® DWU range to deliver various flowrates based on the site ’ s requirements , from low flow for drier mines to very high capacity in wetter mines . “ The ability to pump higher heads per pump , while also delivering higher casing pressure , means Weir can produce a higher total discharge than its competitors . Moreover , it typically needs less pumps in a series to achieve the same discharge pressure . As a result , the overall footprint is smaller , requiring less excavation . The reduced number of pumps reduces capital expenditure , while also lowering operating costs because there are less pumps to maintain and service .”
As a mine gets deeper , Lancaster says that Weir has also developed a solution whereby its Warman ® DWU pumping system can be mounted to a skid and dragged down the mine as it ’ s progressively developed . “ The system obviously needs to be able to handle the higher pressures required at greater depths . To ensure this , Weir utilises variable frequency drives ( VFD ), which allows it to simply speed up the pumps to match the required flowrate of the system as required .” The Warman ® DWU pumps ’ casing pressure capabilities also provide additional flexibility . For instance , if an operator has a two-pump system and they want to go deeper , they can simply add a third or fourth pump to that system to achieve their head requirements . This also allows more traditional cascade pumping systems operating over many levels using a single pump per station to be optimised by combining pumps in series on a single level , thereby reducing the number of operating systems across many levels that need to be attended to and maintained .
One of the other challenges that many mines have to contend with are variable flows throughout the year , depending on climate . “ For instance , in Canada , underground mines experience a lot of water ingress in spring when the snow melts and rains are higher . During these periods , it might be necessary to have two pumps running at a high flowrate and one on standby or , alternatively , it may be more effective to put them on a VFD to control the speed to ensure they ’ re always operating near the best efficiency point .”
Weir concludes that it partners with miners to develop , trial and implement dewatering solutions based on their unique operational requirements and their site-specific needs and challenges . “ Planning for mine dewatering typically happens fairly early in the development of a new underground mine and there are a multitude of factors to consider . Weir has teams of experts and a portfolio of products that ensure it works with customers to provide the ideal solution based on their needs .”
New approaches to tailings dewatering & valorisation
Clean TeQ Water recently established a partnership with mine tailings management company Future Element Pty Ltd . Future Element for its part recently joined Unearthed ’ s Think and Act Differently ( TAD ) program , which is powered by BHP and allows innovators to engage in short experiments designed to de-risk ideas and fasttrack technological breakthroughs . Future Element has joined the Essentials Minerals Cohort and will receive funding , mentoring , access to subject experts , and samples needed to undertake the testing .
Future Element , together with Clean TeQ Water , will be participating in a three-month program of testwork to prepare conceptual flowsheets , which can be applied to BHP ’ s existing and future operations , for tailings dewatering based on the ATA ® technology . The testwork aims to rapidly dewater slurries to produce dry stack tailings while making the critical minerals contained immediately available for recovery . The successful completion of the three-month program would lead to on-site piloting and eventual commercial-scale demonstrations .
The ATA technology was developed to offer a secure and low-cost mine tailings treatment process by rapidly separating water and solids to produce stackable dry tailings and recycled water . The technology uses smart chemistry to rapidly agglomerate the solids in ore slurries . The solids dewater under their own gravity , removing the need for high capital and operating cost pressurised filtration used in the industry today . The resulting materials can be compressed and stacked , with the extracted water being returned to the mine ( or sent for recovery of dissolved metals ), dramatically reducing water usage . In underground mining operations , the compact material may also be used for backfilling , with or without binder .
IM caught up with Brent Slattery , Future Element COO , for more insight : “ Our mission at Future Element is to create a world without tailings dams ; and help mining companies can deliver metals and minerals in a more sustainable way . There is a duality that comes with tailings in that they are expensive liabilities that often represent unacceptable levels of risk but also contain valuable minerals and water . We partner with mining companies to economically rehabilitate their tailings to unlock the value
16 International Mining | MARCH 2024