Chilean Mine Cuts Mill Liner Bolt Removal from 20 Days to 5 with Hydraulic Liner Bolt Punch

As mining equipment grows larger and more automated, one bottleneck has stubbornly resisted change: removing the liner bolts before a ball mill reline. At a copper operation in Chile, the maintenance team was still using the traditional impact method — workers driving out bolts by hand — and the cost showed up directly in the mill's availability. After adopting our hydraulic Liner Bolt Punch together with a Mill Reline Machine, bolt removal time on a medium-to-large ball mill dropped from an industry-typical 15–20 days to just 5 days. The client's feedback was excellent.

Despite continuous improvement and upsizing of mining equipment, and rising automation inside large mills, most domestic operations still remove ball mill liner bolts with manual impact tools. This is the most traditional — and slowest — way to break out bolts, and it creates a cluster of problems that mine operators simply accept as normal:

• Very low efficiency: bolt removal alone can consume 15 days for a medium mill, and up to 20 days for larger units
• High labor intensity: crews work in a hot, dusty, confined mill shell for extended shifts
• Safety exposure: hammering and improvised tooling create real injury risk for maintenance staff
• Long relining cycles: the technology is outdated, and the whole mill stays down while bolts are punched out one by one

For most mines this has been treated as an unchangeable operating reality. It is not.

Our bolt punch was developed specifically to break this old pattern — a high-efficiency hydraulic unit designed to shorten ball mill relining time by replacing manual impact with controlled hydraulic force.

Measured result at the client site: when replacing liners on a medium-to-large ball mill, bolt removal time fell to about 5 days, compared with 15–20 days using the traditional method. That is a massive gain in equipment utilization, and it converts directly into higher output and better economics for the operating company.

Why It Works

• High impact force with zero recoil — the bolt takes the energy, not the operator
• Easy to operate — one technician can run the unit with minimal training
• Precise positioning — accurate alignment on each bolt, less shell damage and rework
• First choice for mill liner bolts — purpose-built for this single, critical application

"Bolt removal is no longer the step that decides how long the reline takes. The punch is fast, precise and much safer for our people. Feedback from the maintenance team is very positive." — Maintenance Superintendent, Chilean copper operation

Relining efficiency is mill availability, and mill availability is production. Manual bolt removal has been accepted as normal for decades — but 15–20 days of bolt work versus 5 days is not a marginal improvement, it is a step change. For any operation still hammering bolts out of a ball mill shell, the hydraulic liner bolt punch is the highest-return upgrade available.