| 摘要 |
A mining machine assembly includes bit supports having primary and secondary cutter bits secured thereto. The bit supports may take the form of bit holders. A drum member may have a plurality of bit holders secured thereto. At least some of the bit holders have two cutter bits secured thereto. A primary cutter bit and a secondary cutter bit are secured to such cutter bit holders. The primary and secondary cutter bits are so positioned as to travel in substantially the same orbital path upon rotation of the cutter drum. The primary cutter bit projects radially outwardly farther than the secondary bit. |
