MINEXPO PREVIEW II
South America have become the strongest international markets for Gridcom with active sales in Chile , Brazil and Colombia . As a result , in 2012 , Gridcom opened a new branch in Santiago , Chile . Gridcom Chile is now fully operating and providing services to local Chilean mines .
The company will be introducing a new aftermarket option for the J model grid resistor at MINExpo . This model takes further advantage of improvements that Gridcom implemented already in the previous version ( D model ), like round openings in the insulator plates or even spacing between the element fins . These have been used for over 10 years in all resistor models Gridcom produces .
Each track on an electric cable shovel includes a series of crawler shoes linked together by steel pins . The total weight of 1,200 to 1,500 t of the machine is applied through the rollers to the crawler shoes in contact with the ground . Yet the weight is not always evenly distributed throughout all the track links , especially when
to have high mechanical properties . Casting can also be made of high manganese steels ( 12 % Mn , Hadfield type ). The foundry process unavoidably induces a coarse solidification structure and metallurgical defects such as internal porosities or surface defects where stress concentration can potentially drive crack initiation . Surface defects are frequently weld repaired and small cracks located in the heat affected zone of the welds can also propagate in service .
The low alloy steel generally provides high tensile properties , typically 1,200 MPa ultimate tensile stress , to face the high pressures . However , the solidification process of castings induces very low toughness properties below about 10 J at -40 ° C paving the way to potential brittle facture and premature failure in service .
Industeel says : “ high manganese steel is wellknown for its very good wear resistance , which is mainly based on its capability to work-harden on the surface under the stress effect . While the surface reaches high hardness , the mechanical
Recently FELUWA has supplied two MULTISAFE double hose-diaphragm pumps for a giant aluminium producer . The pumps are designed to transport bauxite slurry at an operating pressure of some 50 bar and a flow rate of about 150 m 3 / h . FELUWA supplies pumps to feed bauxite slurry into autoclaves to clients worldwide
Maintenance and more
Gridcom Enterprises concentrates on building the most complete range of braking resistors for offroad diesel electric mining trucks and electric loaders . It has been 25 years since the company opened its doors for operations in February 1991 . Those early years were defined by servicing local mines with dynamic braking grid resistor repairs and sales of individual parts , nevertheless it wasn ’ t long before Gridcom Enterprises became a manufacturer of new resistors and started operating as a worldwide supplier . Since then , the USA and
Gridcom J Model resistor to be introduced at Minexpo the machine operates on uneven ground . Some track links can be severely overloaded . This might have serious implications of premature failure without appropriate shoes .
The average lifetime of a set of crawler shoes is limited to some 10,000 to 15,000 hours , especially when machines are working in rocky environments and possibly in cold conditions . More than the short overall lifetime of the track chain set , unexpected isolated failures of single track shoes is a bigger concern , says Industeel , a wholly-owned division of ArcelorMittal . They generate repetitive downtimes to replace single pieces , the cost of downtime being much higher than the price of the track shoe itself .
Crawler shoes are normally made of cast steels which can be low alloy steel heat treated
Design of Industeel ’ s forged track pads
Bucyrus 495 HD equipped with a set of forged track pads
properties of the core remain at its original level , which is usually fairly low ( UTS typically of 900- 950 MPa ). The soft core properties open the door to deformations , for example around the drive lugs and failures induced by local overloading .”
Industeel has recently developed an alternative concept . The material is selected to
56 International Mining | SEPTEMBER 2016