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The feed beam is the component that most directly determines hole accuracy on a development jumbo—it's the structural rail along which the drifter advances during drilling, and its straightness over the full feed stroke length determines whether the drill hole follows the designed trajectory. On the Sandvik DD2710's TF512 feed beam, the rated feed stroke covers the full development round depth in a single rod without rod additions, which means the feed beam's wear condition at the 2.5-meter point affects hole straightness as much as the condition at the start of stroke.
In Swedish underground operations at Boliden's Aitik copper mine—where development headings drive through granite and gabbro at 160–180 MPa—the TF512 feed beam rail surfaces accumulate abrasive wear from the rock dust and drill cuttings that settle on the beam surface during drilling. The drifter's guide shoes slide along those surfaces through 4–8 meters of forward travel per hole, and the drifter is repositioned between 80–120 times per face round. Each positioning cycle adds minor wear at the guide shoe contact points; over 300 face rounds, the cumulative wear opens clearance between the guide shoe and beam rail that allows the drifter to move laterally during percussion.
Feed Beam Wear Monitoring and Replacement Criteria for DD2710
|
Wear Point |
Measurement Method |
New/Serviceable |
Replace When |
Aitik Practice |
|
Rail surface depth |
Depth gauge across rail width |
<0.5 mm groove depth |
≥1.5 mm groove |
Measure at 500-hr service |
|
Guide shoe clearance |
Feeler gauge at shoe-rail gap |
0.1–0.3 mm |
≥0.8 mm |
Check at each face move |
|
Beam straightness |
Piano wire along full length |
<1.0 mm bow over 3 m |
≥2.0 mm bow |
Check after any collision event |
|
End stop condition |
Visual + impact test |
No cracking; firm seating |
Cracked or loose |
Replace at any visible crack |
Aitik operations conduct feed beam rail depth measurements at every 500-hour major service—the measurement takes 8 minutes with a depth gauge and records the wear trend across 6 measuring positions along the beam length. A trend showing 0.3 mm wear per 500 hours allows projection of remaining service life before the next major service. HOVOO supplies TF512 feed beam wear components and guide shoe sets for the DD2710. References at hovooseal.com.
