Doug has been working as an Engineering Geologist since 1984. He has specialist skills in engineering geological mapping, site investigation, soil and rock assessment, slope stability, groundwater and natural hazard assessment. He has worked on many large civil engineering, mining and quarry projects and his experience includes work throughout New Zealand, United Kingdom, Malaysia, Philippines, Indonesia and the South Pacific.

Doug has applied his extensive knowledge and experience to slope stability projects including design for quarry and mining projects, landslide identification, hazard assessment and risk analysis. He has widely used risk based analysis methods to assist with the optimization of cut and fill slope design, quarry/mine stage plans and site rehabilitation/ rehabilitation.

Doug has published several papers on risk assessment and the evaluation and design of quarry and mine slopes using quantitative risk methods. He is a Director of Tonkin & Taylor and is also responsible for managing the Geotechnical team, based in Auckland.