An Australian iron ore operation was losing significant crusher productivity to oversize rock fragments requiring secondary fragmentation before crusher feed. Existing secondary fragmentation by blasting was causing pit closure delays. Three HCN HB-3000 hydraulic breakers — rated 12,000 J impact energy — on Hitachi ZX490 excavators reduced secondary fragmentation cycle time by 34% and eliminated pit closure requirements during secondary breaking operations.
Challenge The Problem to Solve
The mine's primary blasting fragmentation program was producing a consistent 15–18% oversize fraction that could not pass the primary crusher's 800 mm top-size limit. Secondary fragmentation by blasting was the existing method, but each blast required a 2-hour pit evacuation, significantly disrupting mining operations.
The site considered purchasing two additional surface drills for secondary blast holes, but the capital cost and operational complexity led the mine manager to evaluate hydraulic breaker alternatives.
Solution The HCN Approach
After reviewing the rock hardness data (granite and banded iron formation, UCS 180–220 MPa), HCN recommended the HB-3000 large-class hydraulic breaker with a 95 mm moil point tool, mounted on the mine's existing Hitachi ZX490 excavators (49 tonne operating weight).
The HB-3000's 12,000 J impact energy was verified through factory testing against HCN's internal certification procedure before shipment. The nitrogen accumulator pre-charge was set to the high-energy configuration (60 bar) for maximum impact velocity on the hard iron formation material.
HCN provided moil points forged from imported Swedish H13 tool steel, rated for 250–350 hours in medium-hard rock. A supply of three spare moil points per machine was included in the initial order to maintain operations without waiting for international shipping on consumables.
Results Measurable Outcomes
"The decision to switch from secondary blasting to hydraulic breakers was straightforward once we saw the productivity data. The HCN breakers handle our granite and BIF material without difficulty, and we have reclaimed the 2-hour blast evacuation windows from our mining cycle entirely."
Mining Superintendent, Iron Ore Operation, Western Australia