BMT WBM brings further innovation to the mining industry with a new modification and repair scheme designed to dramatically improve the fatigue performance of cluster joints on existing tubular dragline boom designs. Once implemented, this modification can significantly reduce maintenance and inspection workloads for tubular boom draglines with long-term deterioration of existing clusters.
Draglines have long booms comprising of a number of tubular chords with interconnecting lacings welded to the chords at cluster joints. Stresses concentrated at the cluster joint weldments lead to fatigue cracking over time.
Charles Constancon, Director of Canadian Services at BMT WBM explains that a boom replacement can cost in the region of $20 million and would require a three-month machine downtime. However, BMT’s new proposed modification will allow the cluster design to be upgraded and repair costs reduced to approximately $2 million.
The construction comprises of a Reimann plate that provides an interface between the main chord and tubular lacings at a cluster joint. This design allows the lacings from the chord to be cut away, providing easy access to damaged or previously-repaired material. The exposed chord can then be inspected and fully weld repaired before installing the plate.
According to Charles Constancon, aside from the limited maintenance schedules and the outage costs associated with lowering the boom, such an operation is viewed by operators as a dangerous exercise exposing them to a potentially high risk task with major financial consequences.
BMT’s patent-pending modification and repair solution not only significantly extends the life of existing tubular boom and mast structures, but can also provide excellent access for weld repairs to take place, minimising the safety risks for operators.