The effect of changes in tool tip angle on the cutting performance of a pointed pick

ABSTRACT:

Many types of mining machines use pointed style picks in the excavation of weak and medium strength rock ranging from coal and evaporates to shales and sandstones. This paper explores the effect of the initial onset of pick wear on changes in the cutting performance as reflected by an increase in pick tip angle at varying depths of cut using two different rock types. Rock cutting tests were performed in Gambier limestone and Gosford sandstone at depths ranging from 5 mm to 20 mm using a pointed pick having tip angles of 70°, 90° 100° and 110°. The results reveal an increase in tool angle has a more pronounced effect on normal force with a three to four-fold increase compared to less than a two-fold increase in cutting force. Forces and specific energy were also found to increase with depth of cut over the range of tip angles.

Keywords:

• Machine mining
• Rock cutting
• Picks
• Tool wear

Acknowledgements

The authors would like to thank Mr Kanchana Gamage and Mr Mark Whelan for their assistance in commissioning the Portable Linear Cutting Machine at UNSW.