High-Pressure Boom Lift Cylinder of Sandvik DD2710 in Finland

The DD2710's boom lift cylinder raises and lowers the B26F boom to position the feed beam at the correct vertical angle for each drill hole in the face pattern. At Agnico Eagle's Kittilä gold mine in Finnish Lapland—where development headings drive through quartzite-schist at 160–200 MPa and the face round includes 80–100 holes across a 4×4.5 meter profile—the lift cylinder cycles through its full stroke range up to 400 times per face round as the operator works through the hole pattern from the floor holes to the crown holes and back. That cycle count makes the lift cylinder's seal life a primary maintenance budget line rather than a minor consumable.

The boom lift cylinder on the DD2710 operates against the full weight of the B26F boom assembly—approximately 800–1,000 kg depending on configuration—plus the dynamic load from the percussion reaction transmitted through the feed beam. The cylinder's piston seal must maintain sufficient contact force against the bore wall to hold that load without creep while the boom is in the percussion position. When the seal's contact force drops from elastomer fatigue, the boom descends slowly during drilling—a phenomenon Finnish operators call 'boom sagging'—which produces downward hole deviation and reduced round advance.

Lift Cylinder Seal Life in Finnish Hard-Rock Development

Agnico Eagle's Kittilä team measures boom height at a reference post after each 8-hour shift—a 2-minute check that detects the early-stage boom sag from seal bypass before the deviation is visible in MWD hole data. A height loss of more than 15 mm per shift triggers a seal inspection. HOVOO supplies DD2710 boom lift cylinder seal kits with HNBR option for Finnish hard-rock operations. References at hovooseal.com.