Pells Sullivan Meynink

Contact Us

Garry Mostyn

Principal Geotechnical Engineer


Principal Geotechnical Engineer at PSM, Garry Mostyn has over 40 years’ experience in foundation engineering, slope stability, rock mechanics and underground structures. He is a graded arbitrator and has provided expert advice and evidence in numerous legal disputes.

Garry has experience in most aspects of geotechnical engineering. With extensive experience producing geotechnical designs that accurately meet clients’ needs, Garry has undertaken and supervised geotechnical investigations on several hundred projects throughout Australia, Thailand and Papua New Guinea.


Garry has been an active member of several national and international code and practice committees and been involved at the highest levels of the Australian Geomechanics Society (AGS) and the International Society for Rock Mechanics. He is a frequent speaker at professional society meetings and symposia in Australia and overseas.

Garry has authored and co-authored over 80 journal and conference papers in his fields of expertise. Since its inception in the 1980s, Garry has been a member of the Standards Australia drafting committee for AS3798, the Earthworks Code. He is also the chair of the drafting committee for AS4678, the Earth Retaining Structures Code.

Professional development

Garry retains an Adjunct Associate Professor appointment at UNSW where he has lectured extensively in geotechnical engineering including presenting postgraduate courses in foundation engineering, slope stability, dam engineering, rock mechanics and underground structures. He has also completed research on the stability and reliability of slopes and the engineering properties of rocks and rock masses.


Garry’s fields of special expertise include:

  • Foundation engineering
  • Deep fills, earthworks and embankments
  • Slope engineering
  • Rock mechanics
  • Pavement engineering
  • Geotechnical risk analysis.