Evans' theory for chisel shaped picks is well known in the field of rock
cutting technology. It has been widely accepted as a good mathematical
description of how coal and other rocks break under the action of a simple
wedge or chisel. Subsequently, Evans proposed a corresponding theory
for pointed shaped picks. Theory along with experimental evidence from
the laboratory has consistently shown that chisel picks are more efficient
than pointed picks. However despite such evidence, pointed picks
continue to be the preferred shape in most practical cutting applications. Evans' theory for pointed picks was developed in an attempt to shed
light on this apparent incongruity. The theory although predicting forces
of the right order was found to be deficient in several respects. This paper examines Evans' theory for pointed picks and proposes
changes to it, which brings the theory much more into line with measured
data. The issue of the relative efficiencies of chisel and pointed shaped picks
is also examined on a theoretical basis and the apparent incongruity is
Resolved.