Predictive maintenance at Nexa generates a saving of USD 134,600 and 18 days of production

Dynamox’s predictive maintenance solution allows clients to often replace corrective interventions with planned interventions, saving time, productivity, and money. This is what happened in another Nexa success case, which relies on an excellent team in its AMC (Asset Monitoring Center) combined with the Dynamox solution.

In Vazante/MG, Nexa’s main reducer in the calamine mill was operating under normal conditions. However, its vibration levels were increasing, reaching alert level A1 (attention) on the Web Platform on 01/22/2024. On this date, Nexa’s predictive team conducted a detailed analysis of the asset’s health.

Reducer – RMS Velocity

During the analysis, an assessment was made to determine if there were any changes in the operating conditions of the equipment, such as: feed rate, circulating load, water flow, power consumption, grinding media load, and pinion temperature data. However, none of these parameters showed significant changes that could contribute to the increase in the reducer’s vibration.

Upon analyzing the vibration spectrum, it was identified that there was excessive gear stress effort and backlash in the bearings of the output shaft.

Spectrum – Main Reducer

Acceleration spectrum showing a high amount of modulations in the output rotation frequency of the reducer.

Waveform – Reducer

Waveform graph – Autocorrelation

Circular autocorrelation with 58 divisions, representing impact peaks on the output shaft gear of the reducer.

Linear elevation in peak-to-peak acceleration. After intervention, the equipment is in normal condition according to vibration analysis.

Immediately after performing the predictive report with the diagnosis, the Nexa team purchased the output pinion, bearings, and seals, making the components available at the unit for intervention. Additionally, on January 25th, an equipment inspection stop was carried out, where superficial and premature wear of the output pinion was identified.

Following the evolution of the problem through the graphs on the Web Platform, after the vibration levels reached alert level A2, Nexa’s planned intervention day (02/22/2024) arrived. At this point, the team proceeded with the replacement of the items indicated in the report (output pinion, bearings, and seals).

The maintenance team’s work was efficient, and the effective intervention prevented the reducer from breaking, reducing its vibration from 14 mm/s to 1.5 mm/s, returning it to its normal operating conditions.

If there hadn’t been a planned intervention and the bearings had broken, all the gearing, bearings, and casing of the asset could have been damaged. Additionally, there could have been damage to secondary components such as the electric motor and pinion.

Dynamox Solution – Predictive maintenance

Here’s a comparison between the planned intervention that occurred and how it could have been in the opposite scenario, relying only on corrective intervention:

Planned	Corrective
Bearings, seals, and output pinion: USD 15,400.00	New reducer: USD 150,000
Labor: USD 14,000	Labor: USD 14,000
Production loss: 1.9 days	Production loss: 20 days

So, the Nexa team, along with the Dynamox solution, achieved a savings of USD 134,600 and 18 days of production. This was another excellent success case. Therefore, we congratulate the predictive maintenance team of the mining company, represented by Arley Bruno, Flávio Rosa, and Lucas Maia, for their work.

*real-dollar reference exchange rate R$5.00