DRIVES & CONTROLS
Motors for mines
From large geared mill drives to greater mine electrification strategies , Paul Moore caught up with some of the key players in mining drive solutions
Referred to as the world ’ s most powerful
conveyor system , the new installation at
Chuquicamata Underground copper mine in Chile was recently commissioned and tested and is now in full operation . Innovative in its design and scope , with extensive underground and surface flights , it was designed and delivered by TAKRAF and ABB .
Earlier this year we covered the TAKRAF part of the story . ABB supplied what it says is the “ world ' s highest-powered gearless conveyor drive system ” for the project . Its full scope covered engineering design , the gearless conveyor drives , plus electrical equipment for power supply , energy distribution and automation .
“ Project management and engineering for the full electrical , control and instrumentation ( EC & I ) scope was led by ABB in Germany , with long spells on site in northern Chile to work side-by-side with TAKRAF to equip the site ’ s new underground operation with a large conveying system that overcomes an altitude difference of 1,200 m and covers a distance of almost 13 km .”
The three main 11,000 t / h conveyors feature gearless conveyor drives ( GCDs ) equipped with large ABB AC synchronous motors with a rated power of 5 MW each , resulting in a motor shaft torque of about 900 kNm . With every line in constant use , high availability and low maintenance are essential . Designed with a minimum of transfer stations , just one was required underground , saving a significant project cost .
Based on continuous conveying technology , the infrastructure is completely truckless , eliminating the need for 120 large haul trucks . This results in saving around 130 million litres of gasoline consumption per year , bringing the carbon emissions from 340,000 t / y down to 100,000 t / y . It is also the first transportation system in the world to employ premium steel cable belt type ST10000 from ContiTech for use on uphill tunnel conveyors .
“ This is a new milestone in underground applications for continuous mining . It is the highest drive power ever installed on a conveyor and uses a wide range of features for data aquisition , equipment assessment and process optimisation .” said Ulf Richter , Global Product Manager for Belt Conveyor Systems , at ABB . “ In piloting this gearless drive application with TAKRAF we have overcome tremendous technical and logistical challenges due to underground situations , elevation change and capacity requirements .”
ABB liquid-cooled MV voltage-source frequency converters , together with large synchronous motors , deliver a decrease in active and reactive power consumption . This is highly energy efficient , and without additional network filters .
ABB ’ s Mining Conveyor Control Program ( MCCP ) ensures smooth belt operation and safe synchronisation between High Power Motors and High Power Hydraulic Brakes , necessary for secure operation of steep uphill conveyors . The drive systems also work without mechanic backstops .
A novel embedding concept , developed jointly by TAKRAF and ABB , enables straightforward installation and alignment of the GCD motors , saving
WEG has launched a powerful tool that allows online monitoring of Low Voltage and Medium Voltage motors and inverters
installation time and longer deployment of maintenance teams . This was considered a major benefit compared to existing GCDs in cantilevered construction . The concept also meant motors were 100 % factory assembled and tested . They can also be mechanically disconnected from the drive pulley quickly so operations can continue if drive failure occurs . The total installed drive power for the entire system , including multiple feeder conveyors , totals 58 MW , of which there are 11 x 5 MW gearless synchronous motors .
ABB has also installed its ABB Ability™ Ventilation Optimizer at Chuquicamata reducing carbon emissions and providing clean air to workers in line with the strict HSE requirements . Commissioning was completed in four months . The new underground project is expected to extend operations at Chuquicamata for the next 40 years .
Wabtec ’ s optimised integrated electric drives for mining trucks
GE Transportation , now a Wabtec company , introduced the first commercially viable electric drive system for large mining haul trucks in the early 1960s . Since then , the company says it has helped lead the industry in the introduction of new technology to improve the mining industry ’ s key operational metric , material hauled in cost per tonne . “ These innovations have included the industry ’ s first solid-state control system , the first trolley assist technology for large mining haul trucks , the first AC electric drive system and the first demonstration of hybrid energy storage . With service-proven transmission and electric components , Wabtec is the
68 International Mining | NOVEMBER / DECEMBER 2020