Mantella Trading 310 (Pty) Limited v Kusile Mining (Pty) Limited (191/2014)  ZASCA 10 (12 March 2015) per Navsa ADP [Bosielo & Wallis JJA and Schoeman & Dambuza AJJA concurring]
The Supreme Court of Appeal allowed the appeal and granted an interdict preventing the infringement of a South African patent. It was agreed that the word ‘rigid’ was meant to have its ordinary meaning and the court below could not be faulted for considering the dictionary meaning, namely, ‘stiff, unyielding, not pliant or flexible’. . . . But the qualifications in relation to dictionary definitions of words must be borne in mind.
‘They are, first, that a dictionary meaning of a word serves as a guide and cannot govern the interpretation of a patent specification. Where a word has more than one meaning the dictionary cannot prescribe priorities of meaning. Second, is that even definitions must be read in context. [footnote omitted] The question remains, what is the meaning applicable in the context of the particular document under consideration’.
 The step forward claimed by the patent in suit is one that is based on a combination of known techniques and, in hindsight, one might rightly marvel at its simplicity. It is common cause that the patent in suit is successfully and extensively employed in mines in this country. In Roman Roller CC Corbett CJ stated that simplicity is not an obstacle to a step being recognised as being inventive. He said the following at 417J–418A: ‘Experience has shown that a number of simple inventions have constituted patentable subject-matter. Moreover, one must guard against the snare of hindsight, while at the same time not over-compensating for this factor.’