[6] In 1970, Wellington engineer Jim Macdonald built the prototype for a new vertical shaft impactor for creating construction aggregate.
[8] Over a period of eight years, Bartley and Macdonald developed the prototype into a viable commercial machine that became known as the Barmac crusher after its two creators.
[9] By 2003 over 3500 Barmac crushers had been sold worldwide, the largest rated at 800 kW,[10] and it has been used on projects including the Three Gorges Dam in China.
[11] The original Barmac crusher, machine number 1, is preserved at the Kiwi Point Quarry in Ngauranga Gorge, Wellington.
[12] In the 2000 New Year Honours, Bartley was appointed an Officer of the New Zealand Order of Merit, for services to engineering and the community.