Reduce machine failures and downtime

The clients processing plant utilizes a three-stage crushing system. Fresh ore is crushed by a Primary Jaw Crusher (10CRU01) designed to accept feed directly from the ROM and produce a product size of 130mm. After screening, primary ore is fed through two additional crushers (known as Secondary, 10CRU02 and Tertiary, 10CRU03) to achieve a nominal product of 10mm prior to entering the milling circuit.
At the same time maintenance teams perform regular on line and offline checks of moving parts. This includes temperatures, vibration and general visual checks.

Traditionally measurements from these inspections are recorded on service sheets. Readings are compared to a specification to trigger a response. If the measurements are within this specification there is no further action required. Paperwork is generally reviewed by maintenance supervision for any irregularities and feedback prior to filing.

The pitman assembly of a jaw crusher is the moving section of a crusher which crushes rock by pinching it against a fixed portion of the crusher assembly. It ‘rocks’ by nature of an eccentric shaft which is supported by bearings and driven by an electric motor. The shaft is also attached to a fly wheel which maintains momentum of the pitman assembly.

Around the end of February 2019, the pitman bearing was running as usual with regular checks being carried out. What was different was that these regular temperature measurements were being entered in to the Obzervr app and trending in almost real time on its Analytics Platform. Around March 2020, even though the bearing temperatures were below threshold, a trending rise in temperature was noted and triggered an alarm to the team.

In response the team closely monitored the faulty bearing. Additional grease was added however this failed to slow the temperature rise. Infra-red thermography confirmed the temperatures and the decision was made to strip and assess the pitman assembly and bearings.

It was found that the bearing had suffered internal failure and while the shaft was damaged it was repairable. Had the pitman shaft failed catastrophically the impact to the business would have been significant. The failure could have meant downtime of the crushing circuit in excess of 22 weeks, the quoted time to have a new set up manufactured. This would have meant downgrading the current 1000 ton jaw crusher to a 50 ton jaw crusher for 22 weeks. This would have caused profound loss in production for the client organisation.

Key take-away

By digitising and trending the bearing temperature readings, the mine maintenance team were able to pro-actively identify an impending failure at a point well ahead of what was possible in the past. Their swift action avoided a catastrophic machine failure which left unattended, would have led to a substantial business impact.
The single saving from repairing the shaft more than covered the entire 1st year fees of the Obzervr solution across 5 of the clients mine sites.