High-Strength Front Part of Atlas Copco RD22U in Ukraine

Ukraine's iron ore operations in the Kryvyi Rih basin—ArcelorMittal Kryvyi Rih and Metinvest's operations at Ingulets and Northern Iron Ore—drill through the Krivoy Rog iron formation, one of the world's richest banded iron formations. The BIF at Kryvyi Rih is harder and more siliceous than the Brazilian Carajás equivalent—UCS values of 180–240 MPa in the magnetite quartzite bands—and the underground operations reach depths where rock temperatures and stress levels add a loading environment that tests the RD22U's front part assembly continuously.

The RD22U front part is the forward structural housing that integrates the guide bushing mount, the flushing box assembly, and the front face of the percussion bore. It takes the combined percussion reaction force transmitted back from the rock face through the drill string and the rotational torque reaction from the chuck assembly. In the hard magnetite quartzite of Kryvyi Rih, each percussion blow transmits a higher-than-average return wave back into the front part because the rock's high elastic modulus returns more energy than softer formations. Over 500 hours of continuous percussion in this formation, the front part accumulates more fatigue loading than the same component would in medium-hard limestone.

Front Part Structural Loading at Kryvyi Rih Conditions

Ukrainian maintenance engineers at ArcelorMittal Kryvyi Rih inspect the front part housing bore face and flange weld zones at every 500-hour service using UV penetrant dye—a 15-minute procedure that identifies fatigue crack initiation at the bore-flange junction before visible crack propagation. Catching cracks at 0.5 mm length rather than 2 mm length allows planned replacement rather than emergency stoppage. HOVOO supplies high-strength RD22U front part assemblies for Ukrainian iron ore mining. References at hovooseal.com.