Norbar Case Study

EziTite Hydraulic Head Nut for Evolution Mining Cone Crushers

Improving safety and efficiency of Mining equipment maintenance.

Evolution Mining Mungari Site

The Mungari gold operation is located 600 km east of Perth and 20 km west of Kalgoorlie in Western Australia. It comprises both underground and open-cut gold mines.

Critical Equipment Maintenance

As part of the gold mining operation, ore is collected and crushed in Nordberg HP4 cone crushers. These crushers depend upon controlled assembly and maintenance operations to ensure that they remain operational and functioning reliably and productively. The crushers are serviced approximately every six weeks.

Safety Risks and Inefficiencies

The inner crushing cone or ‘mantle’ is an integral part of the crushing mechanism and is subjected to enormous force during operation. This hard-working part needs to be replaced regularly. To access the mantle for servicing, the factory-supplied mantle nut that fixes the mantle in place must be removed. The mantle nut includes a sacrificial burn-ring that is oxy cut to first release pressure before being removed, discarded, and then replaced.

To re-tighten the mantle nut bolts after servicing, technicians were applying force to a flogging spanner using a sledge hammer. This meant that there was in little to no control of the load being applied to the bolts. Manual flogging of the spanner is dangerous, carrying a risk of strike injuries as well as being physically strenuous.

Servicing the cone crushers using this method took around four to five hours to complete, and required two to three personnel. Employees based at the site identified this as a hazardous and time consuming process, prompting the search for a solution.

The Solution

Norbar recommended the Technofast EziTite® Hydraulic Head Nut System to replace the factory-supplied mantle nuts, and a sample was supplied for trial. Following initial testing, a few changes were made to fine-tune and improve the design to perfectly suit the application.

How it Works

The EziTite® Hydraulic Head Nut assembly is screwed onto the bolt (replacing the original Nut) until the base is tight against the working face. Hydraulic pressure is then applied through the nipple fitting on top of the nut body into the sealed chamber, forcing the piston and the nut body apart to stretch and tension the bolt through the joint.

The threaded lock ring, mounted on the nut body, is then screwed against the abutting face to retain the induced load in the bolt. Pressure is then simply released and the hydraulic coupling removed from the nipple fitting to complete the operation.

The client ordered a total of four hydraulic head nuts for the HP4 crushers. Two fitted and two waiting to rotate on the change out.

See the EziTite in action:

Watch video

Key Benefits

Safe — Eliminates strike injury risks by removing the need for flogging spanner and sledge hammer.
Time and Cost Saving — 4 hours with 105 change-outs is estimated to be 17.5 days per year and only using 2 employees.
Long Lasting — Sacrificial cover made more robust for extended life.