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Harder, Tougher, Longer Jaw Liners

| Terry Fitzgerald |

Working in conjunction with one of our dealers, Foothills Steel Foundry successfully made significant improvements to a clients’ Komatsu BR380 jaw crusher, which was processing oversize rock from an underground gold mine.

Komatsu BR380 HD Jaw - Solidworks Design
Komatsu BR380 HD Jaw – Solidworks Design

The wear life of their original jaw liners was only in the 90-110hr range, with the top of the fixed jaw showing heavy wear from oversize rock rolling, not fracturing and moving through the crusher.

The fast wear of the OEM style, standard manganese jaws was creating a real risk of the crushing contract not being profitable.

So, faced with a real wear issue, the client asked Foothills Steel Foundry to assist with their problem, not really knowing what the solution would entail.

Understanding the problem was key for Foothills, what was wearing, where and why?

The initial fracture of the large, hard rock being fed was difficult to achieve, causing some of the oversize rocks to roll at the top of the crushing chamber.  When the rock was reduced and passing through the crusher, the high silica content was preventing a work hardened surface from forming on the jaw plates.

The high compressive strength of the rock was hardening the jaws on impact, but the high silica content was removing it almost immediately through abrasion as the reduced material moved through the crushing chamber.

Foothills used their experience in other high wear environments to work on redesigning the Komatsu BR380 jaws and trialed their new version out on the oversize gold product, the results were outstanding with a significant improvement recorded.

The technical differences included changes to material, jaw and crushing chamber shape, and tooth profile.

Making the tooth larger, with a more pronounced point helped concentrate the crushing force with a point load on the rock and help get the initial fracture.

Cente cutaway of Foothills Heavy Duty Komatsu BR380 Jaw
Cente cutaway of Foothills Heavy Duty Komatsu BR380 Jaw

By increasing the curve on the fixed jaw allowed some of the larger rock to enter the crushing chamber a bit further, stopping the rolling effect and getting the initial facture easier.  The curve changed initial the nip angle initially and allowed crushing in the middle of the chamber.  This stopped the crusher only wearing out the ends of the jaws by allowing the middle of the jaws do some of the crushing.

More material was added between the tooth valleys and lightening pockets,  allowing the jaw to be pushed past the point that no teeth are left, if needed.

Foothills upgraded the material to ultra heavy duty 24% manganese. This material has much more abrasion resistance and holds the work hardened surface longer against the abrasivce effects of the high silica content rock.

The combination of all the changes meant that at 60 hours the jaws were only 20% worn.  This meant longer service time before the jaws needed turning, and an average service life of 300+ hrs, an increase of over 300% compared to the OEM style jaws.

Foothills Heavy Duty BR380 Jaws after 111 hours, the original jaws were worn through at this stage
Foothills Heavy Duty BR380 Jaws after 111 hours, the original jaws were worn through at this stage

By redesigning the jaw plates the processing of the oversize rock from the underground gold mine now has increased efficiency and reduced operational cost from an increase in lifespan of the jaw.  This means fewer change outs and associated costs with the maintenance and downtime during a change out period.

With an increase of nearly 300% in production lifespan whilst still achieving reduction targets, Foothills have created an aggressive competitor product in the market.

Foothills Steel have managed to not only increase performance, but decrease downtime as a result of a jaw plate and crushing chamber redesign.

With an ability to reverse engineer or design a new solution for any wear part or crushing problem, Foothills really are a leading supplier of wear parts and custom casting solutions in Australia today.