COMMINUTION & CRUSHING
measure the tonnage being processed ,” Elias explained . “ The processed ore is then dumped onto a 14-m-high stockpile .”
This plant is looking to solve a challenge that most – if not all – large copper mines face globally : an increase in pebble production relative to an operation ’ s ability to process said pebbles .
“ What we ’ re seeing is that many of the existing pebble crushing circuits aren ’ t able to handle the extra capacity and , thus , are no longer fit-forpurpose ,” Elias said . “ As a result , a lot of miners are stockpiling vast quantities of pebbles .
“ A decade ago , these were seen as less valuable , but , with declining ore grades , the
value proposition has changed , and these unprocessed pebbles may hold the key to ensuring mining companies meet their production targets .”
ABB ’ s drive for efficiency
ABB , through its drive systems portfolio , straddles both camps in the aforementioned comminution space – operations using SAG / AG & ball mills , and those using HPGRs and vertical milling technology .
On the former , ABB has successfully supplied gearless mill drives ( GMDs )
ABB recently reached a major milestone of 160 gearless mill drive units sold
to operations since 1969 – with its first copper installation coming in 1985 . On the latter , it has supplied HPGR drive systems to high profile mines across the globe , like Southern Peru Copper ’ s Toquepala mine .
Like other companies and experts consulted for this article , ABB sees the relevant use of these technologies depending on the application at hand .
Wilson Monteiro , Business Line Manager , GMD , ABB , explained : “ HPGR and vertical mills ( such as Vertimills and stirred mills ) have shown promise in some applications , especially for certain types of ores . However , when we compare the efficiency between the drive powertrain of GMDs , RMDs ( ring-geared mill drives ), HPGRs and Vertimills , the GMD is always more efficient due to its intrinsic construction characteristic .” GMDs do not have an intermediate power transmission system , enabling an efficiency gain on HPGRs / vertical mills of around 2-4 % depending on the model , according to Monteiro .
A wider awareness of this fact has led to ABB ’ s GMD sales surging over recent decades .
“ It took us 32 years to reach a production of 40 GMDs , then we doubled the quantity in eight years , and then it took another 15 years to double it again , reaching , today , around 160 units sold ,” Monteiro said .
With ore grades continuing to fall , Monteiro envisages the need for even larger GMDs than the 28 MW ones the company has supplied the sector to date . These GMDs will , he says , prove to be even more efficient in operation than using two or more HPGR / vertical mill units .
This efficiency is key when it comes to mining companies achieving their climate change goals , as Monteiro explained .
“ The use of more efficient solutions will play a key role in future decision-making processes ,” he said . “ Any gain in efficiency , no matter how small , will have a huge impact on reducing carbon emissions . As mentioned before , the gearless motor technology offers the highest availability ,
48 International Mining | SEPTEMBER 2023