Meet our Team

Dr. Andy Robertson has a B.Sc. in Civil Engineering, a Ph.D. in Rock Mechanics and 30 years of experience in mining geotechnics and environmental engineering. His experience includes periods of work with a mining company and specialist foundation construction contractor, providing him with practical field experience. In the 27 years he spent as one of the three senior principals of Steffen, Robertson & Kirsten and as the president of Robertson GeoConsultants Inc., he has been responsible for the development of the mining geotechnical and environmental engineering practices in the areas of:

He has been the lead investigator and/or designer for numerous project teams for mining companies and provides review and senior evaluation and counseling to a number of mining companies, research establishments, professional associations and provincial, state and federal agencies. Dr. Robertson participates on numerous technical review boards for mining companies and regulatory authorities. He has published extensively, participated in the drafting of numerous technical guides currently used by industry and regulatory bodies alike, and has been the recipient of a number of technical and industry awards.

Dr. Christoph Wels has a B.Sc. in Hydrology, a M.Sc. in Watershed Ecosystem Studies and a Ph.D. in Hydrogeology with over 20 years of professional experience in academic research and consulting. He has published several scientific papers in the areas of contaminant hydrogeology and watershed hydrology. Dr. Wels is Principal and Senior Hydrogeologist with Robertson GeoConsultants Inc. and specializes on groundwater modeling and evaluating the impact of mining projects on groundwater resources. He joined Robertson GeoConsultants in 1995 and has since been consulting to the mining and environmental industry in the areas of:

As senior hydrogeologist of RGC, he is responsible for all aspects of hydrogeological investigations from field work to detailed groundwater flow and transport modeling. His fluency in English, Spanish and German allows direct communication with clients and regulatory agencies all over the world.


Jack Caldwell, P.Eng, has a B.Sc. in Civil Engineering, an M.Sc. (Eng.) in Geotechnical Engineering and a post-graduate law degree. He has over 35 years engineering experience on mining, civil, geotechnical and site remediation projects. He has worked on numerous projects throughout southern Africa, Europe, Canada and the United States. His project experience includes:

In addition, Mr. Caldwell has been the lead specialist for various geotechnical and civil engineering projects in Southern California. Mr. Caldwell has written many engineering reports, proposals, and technical papers. He is the lead author of the book, Principles and Practice of Waste Encapsulation, on the design of waste disposal facilities for radioactive and hazardous wastes.

Dr. Paul Ferguson completed his Ph.D. in Earth Sciences in 2007 with a focus on isotope and trace element geochemistry. He has ten years of experience in the fields of environmental geochemistry and hydrogeology and specializes in characterizing the impacts of acid rock drainage (ARD) and metal leaching (ML) on groundwater and surface water quality and the determining the implications for mine closure.

Paul has worked closely with regulatory agencies, mining companies, and other consulting firms during the pre-feasibility, active mining, and closure stages of mining projects in Canada, Chile, and Australia so is well-versed in the permitting process & required regulatory interface during various stages of mining.

Paul is RGC’s project lead for closure planning at Nyrstar Myra Falls in western Canada and at the former Rum Jungle Mine Site, an abandoned uranium mine in Australia’s Northern Territory. He has also worked at the former Mount Morgan Mine Site in Queensland (Australia) and the Faro Mine Site in Canada’s Northwest Territories, as well as on several active mines in northern Canada and Chile.     

He joined Robertson GeoConsultants in 2008 and has been a consultant to the mining and environmental industry in the areas of:

Dr. Mahmoud Hussein has a B.Sc. in Civil Engineering, an M.Sc. (Eng.) in Groundwater Modelling and a Ph.D. in Hydrogeology. Mahmoud joined Robertson GeoConsultants Inc. in 2016 as a hydrogeologist and groundwater modeler. He has over 10 years of consultancy and research experience in the areas of:

  • Groundwater flow and solute transport modelling;
  • Aquifer storage and recovery testing;
  • Design, implementation, supervision and interpretation of hydrogeological investigations;
  • Analysis of aquifer and well performance testing; and
  • Time series analysis applied to borehole water levels response to natural and anthropogenic influences.

Mahmoud Hussein has written 3 papers on groundwater flow & contaminant transport modeling, time series analysis and groundwater vulnerability. 

Andy Thomas is a Geological Engineer with over nine years working as a consultant in the field of ground engineering.  His academic background is in civil engineering and science, specialising in geology.  He has professional experience in geological and geotechnical site investigation; characterization, design, specification and construction stage supervision of foundations and earthworks for projects in the mining and civil sectors.  Specialist experience includes soil and rock slope stability analyses.  Other areas of experience include hydrogeology and contaminated site investigations.  Andy has worked on a wide variety of projects in Australia and Canada, recently focusing on mine site remediation.

In 2014 Andy completed his master’s degree in the field of geological engineering at the University of British Columbia.  Particular focus was on engineering rock mechanics, specifically the behavior of rock under high stress conditions.  Prior to this, certification was achieved with Engineers Australia as a Chartered Professional Engineer (CPEng). 

Aida Farkish, EIT, has a M.A.Sc. in Geo-Environmental Engineering with focus on tailings and solid waste management. Since joining RGC, Aida has been providing technical services focusing on dewatering of oil sands MFT, supervision of geotechnical field investigations, and design and supervision of specialized geotechnical laboratory testing.

She joined Robertson GeoConsultants in 2014 and has been a consultant to the mining and environmental industry in the areas of:

  • Oil sand Mature Fine Tailing (MFT) treatment and dewatering,
  • Hydrological modeling,
  • Geotechnical laboratory testing, and
  • Project management.

Tara Raketti has a B.Sc. in Environmental Engineering and in Biology. She is an Engineer-In-Training in the province of British Columbia with over two years of professional experience in mining hydrogeology and environmental analyses. Tara joined Robertson GeoConsultants Inc. in 2013 first as a co-op student and again as an environmental engineer upon completion of her degree.

Her experience includes supervision of drilling and well construction, hydraulic testing, hydrological analyses, water quality sampling, and QA/QC analysis.



Alex Trapp has a M.Sc. in Water Resources Engineering and Management and a B.Eng. in Civil Engineering. He has three years of professional experience in mining hydrogeology and environmental analyses. Alex joined Robertson GeoConsultants Inc. in 2012 as a Water Resources Engineer and again in 2016.

His technical experience includes planning and supervision of drilling programs, hydraulic testing, well installation, and water quality sampling. Alex also has experience in numerical groundwater flow and transport modeling ranging from 1D models for seawater intrusion and seepage analysis to large, complex 3D models in support of mine water management. Furthermore, he has experience in reviewing geotechnical testing and finite strain consolidation modelling for tailings seepage analysis.