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The DD2710's hydraulic tank is a component that rarely gets attention until something goes wrong—and when it goes wrong in Finnish underground operations, the consequences are disproportionate to the attention it doesn't receive. At Agnico Eagle's Kittilä and Boliden's Pyhäsalmi underground operations, the hydraulic tank serves three functions simultaneously: it stores the hydraulic oil volume for the entire circuit (percussion, boom, tramming, and flushing circuits combined), it provides the residence time for entrained air to escape from returning oil before it re-enters the pumps, and it houses the return line filter and temperature gauge that are the first indicators of system health. A tank that has developed an internal rust layer—from moisture condensation during cold Finnish nights—is shedding rust particles into the oil that bypass the return filter's nominal rating.
The long-life specification for the DD2710 hydraulic tank refers primarily to two design features: a stainless steel or epoxy-lined interior that resists the moisture condensation corrosion that affects unlined steel tanks, and a drain plug position that allows complete oil drainage without dead volumes where contaminated oil accumulates.
Hydraulic Tank Maintenance for Finnish Underground Operations
|
Maintenance Item |
Frequency |
Method |
Why It Matters in Finland |
|
Oil sample analysis |
Every 300 hrs |
Drawn from drain port; lab particle count |
Cold condensation accelerates rust; detects before pump damage |
|
Return filter element |
500 hrs or sooner if high ΔP |
Replace; inspect housing for rust scale |
Rust flake can block filter and allow bypass |
|
Tank interior inspection |
Annually |
Drain fully; torch inspection |
Rust scale on walls = ongoing contamination source |
|
Breather filter |
500 hrs |
Replace; check for moisture indicator |
Cold nights create condensation if breather is blocked |
Boliden's Pyhäsalmi winter protocol includes running the DD2710's hydraulic circuit on circulation for 15 minutes before any boom or percussion operation after overnight parking in sub-zero conditions—the circulation warms the oil and allows condensation water to mix and pass through the return filter rather than sitting at the bottom of the tank where it promotes rust. HOVOO supplies DD2710 hydraulic tank seals, filter elements, and breather assemblies. References at hovooseal.com.
