WASHING SOLUTIONS
Making new waves in manganese
In August 2020 , Australian-based company Element 25 announced that they had made significant investments in long lead time equipment for their Butcherbird Manganese Project in WA south of Newman . This is a world class manganese resource with current JORC resources in excess of 263 Mt of manganese ore . Simple mechanical beneficiation will yield a 30- 35 % medium grade Mn concentrate .
The first stage of the processing plant comprises a jaw crusher which has been sized , selected and ordered from Max Plant , a Western Australian company . The second stage of the process is a dry screen to remove fine grained clay material which will be utilised in civil construction works and / or be disposed of in a dry-stack tail facility . Next up is CDE which is supplying a RotoMax 160 logwasher to facilitate efficient optical ore sorting . The log washer provides an attrition scrubbing step which removes any remaining clays and physically breaks down a portion of the non manganiferous shale material . Two Steinert KSS ore sorters have been ordered from Steinert Australia and will be manufactured at the Steinert factory in Germany . Screens are from Vipro , a South African supplier .
McCormick adds : “ The Element 25 experience has been a very positive one for us . They worked through a small engineering design company that used a modular approach to pull all of the key parts of the process design together including our RotoMax logwasher . They really challenged us to prove the robustness and technical capability of our equipment but we learnt a lot from that process , especially as we were dealing with a new commodity .”
Manganese ore is a bit more brittle than iron ore as an example but the way the RotoMax works in using fluidisation as well as ore on ore contact with little contact between the ore and the actual paddles , means it is ideal for this application . There are other manganese projects in discussion as well , including a very large tender for a manganese producer in Gabon .
“ We feel like there is a critical mass coming together for the AggMax now in mining – we are in iron ore , diamonds and manganese , all of which are big industries in their own right . But it is still challenging , there are a lot of mineral process people who don ’ t know about or don ’ t understand logwashing and will revert just to a rotary scrubber . But the results from a logwasher are significantly better . And the work we are now doing with a major Pilbara iron ore miner will really cement that .”
Iron ore market coming in the Pilbara
This refers to a pilot scale RotoMax that has been delivered to one of the big three WA iron ore mining giants where they are doing some scrubbing testing , and comparing it with traditional drum scrubbing using rotary scrubbers . It was commissioned remotely using video conferencing due to COVID-19 restrictions . “ They didn ’ t want to go with a full scale plant from the outset , but saw what we had done at SIMEC and so opted to take a pilot logwasher which is only 1.5 m long – we built it for them , sent it to their test lab . We are jointly working with them on the testing ; the problem they have is similar to that at SIMEC , they have a low grade ore that was regarded as waste but has potential value . They are comparing RotoMax to other options but we are confident our technology will prove itself the most effective and will lead to ordering of a full sized AggMax plant .”
And to the Americas …
Looking at other hotspots , CDE has had notable success in Brazilian iron ore at Vallourec ’ s mining operations which invested in an AggMax 151 unit back in 2013 . This is a portable log washer with sizing screen integrated onto a single chassis and was integrated within the existing Vallourec processing plant . “ Traditionally in Latin America , mines have used rotary scrubbers but there remains huge potential there to highlight the greater efficiency possible with logwashers . Iron ore aside we are also looking at adapting AggMax configurations to replace trommel set-ups in gold mining operations in Brazil . This includes avoiding any risk of gold becoming trapped within the system .”
In the Canadian oil sands , there is also a lot of potential with CDE equipment to treat oil sands tailings – this involves its ShearClean™ attrition cell equipment , essentially a logwasher for sand , which puts energy into material having industrial sand extraction potential . ShearClean attrition cells are designed to operate at 80 % solids concentration for maximum scrubbing efficiency and a higher specific capacity . There needs to be a chemical input , such as use of polymer flocculants , to remove the bitumen in the oil sands and CDE is talking to several companies that have developed this part of the separation process .
Weir ’ s Trio ® models offer robustness and reliability
Log washers assist in the breakdown of heavy plastic or nonsoluble clay , conglomerates and types of soft stone that may be present in ore , crushed rock or gravel . Scrubbing is accomplished as the corrugated faced , cast-ductile iron shoes mounted on the spuds welded to the log shafts , rotate in opposite directions . While the iron shoes move the material , the majority of cleaning is a result of the stone-onstone contact as the feed travels up the cleaning chamber , before being discharged out the bottom of the washer box .
Since Weir Minerals acquired Trio ® in 2014 , the company has established a range of products that incorporate robust reliability and ease of operation . Kristofer McCue , Marketing Manager – Comminution at Weir Minerals comments : “ Constructed using heavy steel plates , Trio ® TLW series log washers are designed heavier than other log washers available in the market . Their added weight reinforces the product ’ s reliability in even the toughest applications . In addition , these log washers have a flexible spider coupling which protects the rotating shaft from thrust loads and gear reducer against vibrations .” Trio ® TLW series log washers feature 35 ft long washing tubs with either 36-in or 44 in-wide shafts .
All Trio ® log washers are precisely timed before leaving the factory , ensuring proper log shaft mesh . “ Underlining Weir Minerals ’ commitment to supplying a robust solution , all Trio ® log washers include an ‘ extreme duty ’ gear reducer , with compound heat-treated helical gearing . This system ensures 100 % of the thrust load is carried by the output shafts . The gearing runs in a sealed oil bath , this protects the gears from contamination and allows the TLW series to tackle challenging applications which other suppliers would otherwise avoid .”
McLanahan builds on original invention
The original Log Washer was actually invented in 1891 by Samuel Calvin McLanahan , the second generation of family ownership of McLanahan Corporation , to remove clay from gravel , various types of ores and crushed stone to improve the quality of the material . McLanahan states : “ Samuel Calvin ’ s design featured paddles bolted to squared-off tree logs , which is how the log washer got its name . The paddles on the counter rotating log shafts agitated the material to facilitate particle-on-particle scrubbing as well as moved the cleaned material toward the discharge end . Liberated clay was removed with the wash water from near the feed end of the machine .”
Constructed using heavy steel plates , Trio ® TLW series log washers are designed heavier than other log washers available in the market . Their added weight reinforces the product ’ s reliability in even the toughest applications
OCTOBER 2020 | International Mining 53