IPCC TECHNOLOGY
The ABB gearless conveyor drive installed at the Bílina mine reduces energy consumption by an estimated 6-10 % whilst maintaining materials handling efficiency
The multiple benefits of using low-speed gearless drives in conveyor systems when it comes to the environment and production efficiency were illustrated during a groundbreaking project involving the installation of a new 333 m-long ‘ green ’ E1 conveyor system at the Bílina coal mine in the west of the Czech Republic , which is owned by Severočeské doly a . s .
Conscious of the impact the mine has on the surrounding environment – in particular the villages of Braňany and Mariánské Radčice less than 1 km away – Severočeské doly has installed noise barriers and anti-dust measures , alongside greening the extraction and transport of the extracted placer material and mined lignite . Central to this strategy was the mine operator ' s decision - following the successful completion of the first stage of the hauling relocation at the Bílina site - to install ABB slow-speed gearless drives developed specifically for the conveyor system at the site , and designed by Czech company Prodeco , the first time the concept has been used in long-distance conveyor transport in the Czech Republic .
Gearless conveyor drives use a large , lowspeed synchronous electric motor mounted on a pulley shaft designed to handle the high torque that is produced . The motor itself is controlled by a variable-speed drive and produces a shaft rotational speed typically in the range of 45-70 rpm .
The ABB drive installed at Bílina contains a motor that turns at 48 rpm , identical to the speed of the conveyor pulley , reducing energy consumption by an estimated 6-10 %. In compliance with the request from Severočeské doly , ABB designed a customised motor that fitted the existing internal conveyance station . Adapting the new slow-speed gearless solution in size and performance to the original conventional drive means that , if necessary , in future it can be replaced in as little as 12 hours . In that way a step by step upgrade from geared to gearless would be possible .
Other advantages of using this drive include
the elimination of mechanical gears causing wear and tear and thus the possibility of failure in proportion to the period of use . By eliminating the gearbox from the conventional drive , the new concept of the drive unit has resulted in a device with a low risk of failure ( only motor bearings , and coolant ), minimal maintenance requirements ( relubrication of bearings once a year , checking the coolant once a month ) and much lower ambient noise levels .
Another key project requisite was to limit noise from the conveyor . Drives containing gearboxes with multiple moving parts turning at 1,000 rpm or higher run the risk of exceeding the EU noise emissions limit of 85dB ( A ) ( A-weighted decibels ). By running at less than 50 rpm , the slow-speed drive restricts noise emissions from the drive unit to less than 73dB ( A ), negating the need for noise encapsulation ( housing around the whole geared drive unit ) or noise protection walls along the conveyor system .
“ Noise levels from the conveyor system at the Bílina mine were also limited by placing the drive unit at the bottom of the steel structure ( in conventional solutions it is located at the top ) as well as by employing the following damping elements : impact bed , the soundproof design of the transport rollers , low-noise motor cooler , or by using more precise bearings . In addition , the middle parts of the mine conveyor route were specifically designed by Prodeco to reduce vibrations and resonances of the steel structure .”
In terms of dust emissions , the full-circuit overfill seal minimises take-off , while the overfill impact surfaces are lined around the inner perimeter with damping material in order to eliminate noise .
Prodeco ’ s new ‘ green ’ E1 conveyor system , incorporating the bespoke low-speed gearless drive supplied by ABB , was delivered to the customer in Q1 2021 , commissioned in Q2 2021 , and has been running at Severočeské doly ’ s Bílina mine since July 2021 .
In summary , the customer reports the following significant environmental benefits : n A significant reduction in the noise level from the drive ( originally more than 85dB , guaranteed by the ABB manufacturer to be less than 73 dB , and actually measured at 71 dB ) n Dust reduction ( achieved by a complete covering of the tip , equipping the tip at the return station of the downstream conveyor with a shock bed etc ) n A reduction in overall conveyor ambient noise
( more precise bearings , damped rollers etc ) n A reduction of energy consumption by between 6 and 10 %. “ As the project demonstrates , designing both mine conveyor and drive systems with environmental performance front of mind serves the dual purpose of helping operators maintain the efficiency of materials handling operations while simultaneously achieve their ambitious sustainability targets . It has brought benefits to both local communities through the reduction of noise and dust pollution as well as wider environmental benefits .”
DSI Flying Sandwich Belt High Angle Conveyors
Working with Agudio of Torino , Italy , US-based Dos Santos International ( DSI ) has recently developed the Flying Sandwich high angle conveyor , which is an amalgamation of two proven innovative technologies - the Dos Santos Sandwich Belt high angle conveyor and the Agudio Flying Belt . The Agudio Flying Belt was introduced to the world in 2011 at a French sand and gravel operation . Since then additional significant systems have gone into operation in Europe , South America and Asia . Agudio , part of ski-lift specialist Leitner , adapted their expertise to the support of long overland conveyors on suspended wire ropes that could span the landscape between towers , minimising disruption of the landscape . The amalgamation of the technologies was thus a natural step . The Flying Sandwich concept was first considered by DSI more than 15 years ago . The concept was clear but the development process was challenging as the system had to be proven stable in all operating conditions , particularly when subject to cross winds and the phenomenon of vortex shedding . In joining with Agudio for the development , these issues have already been proven and solved in their Flying Belts . DSI Founder Joe Dos Santos added : “ Indeed , Agudio recognised the synergy of our companies as it was they that brought forth the first Flying Sandwich prospect , a downhill Flying Sandwich from a French mountain-side quarry down to the plant . Two additional prospects followed . Our proposals for these revealed some
Three Flying Sandwich proposals to a common scale with notable landmarks
46 International Mining | APRIL 2022