Alex G. Doll


Mineral grinding specialist. Provider of software and consultant in mathematical modelling for grinding system design, bench-marking and optimization.

Metallurgical sample collection program design and execution for scoping and feasibility studies.

Plant audits of operating mills for process improvement.

Training of engineers and operators in comminution circuit operations and optimization.

Expert witness in litigation related to grinding circuit design and throughput forecasting.

Significant programming experience in process modelling and material balance calculations.



Independent consultant providing process engineering and computer consulting to the mining industry. Actively involved in technology transfer by providing short courses and guest lectures on grinding modelling and geometallurgy.

Performing grinding system design, peer review studies, supervising laboratory test programs, expert witness consulting, and operating plant optimization studies. Recent work includes conceptual design support for a site in Chile (ongoing), numerous third-party design reviews, plant optimization studies for plants in USA (2022) and Canada (2022, 2021), brownfield expansion studies and engineering support for a site in México (2020); debottlenecking and plant audits performed at mines in BC (2019), Detour Gold (2018), and Mount Milligan (2017); conceptual design studies for projects in Chile (2019), Serbia (2018), Nova Scotia (2018), and Québec (2018).

Activities include:

SAGMILLING.COM Comminution web site (ongoing)

Developer of "the Internet's first comminution resource" at Web site contains a collection of both free and subscription-based calculation tools to aid metallurgical process engineers perform comminution calculations. The online library of technical articles contain several papers on metallurgical topics including comminution modelling, mass balance calculations and laboratory comminution testwork program information.

REGISTRAR AND WEBMASTER Fifth, Sixth and Seventh International Conference on Semi-Autogenous and High Pressure Grinding technology (2011, 2015 & 2019)

EXECUTIVE EDITOR XXVII International Mineral Processing Congress – IMPC 2014 (2013-2014)

One of three executive editors for the IMPC 2014 conference held in Santiago, Chile.

GRINDING STUDY CONSULTANT DJB Consultants Inc. (2006-2012)

Consultant to a senior grinding system specialist performing detailed calculations, data analysis, testwork program development and supervision, and geometallurgical model creation for comminution studies. Studies include conceptual through feasibility to detailed design and auditing of existing milling circuits.

PEBBLE PROJECT Northern Dynasty Minerals (2005 - 2006)

Project engineer performing project management and process engineering for the owner's team of a 220,000 stpd copper-gold porphyry feasibility study. Duties include supervision of multiple engineering contractors; developing project budgets, procedures and policies; and ensuring technical continuity at interfaces between different contractors.


Process engineer performing material balance calculations and system database development for a froth treatment capacity expansion study.

CNRL HORIZON OIL SAND PROJECT Colt Engineering (2002 - 2003)

Process engineer involved in feasibility study for a 270 kbpcd oilsand mine. Duties include material balance calculations for bitumen extraction and froth treatment process options and support of unit operation selection trade-off studies.

MUSKEG RIVER OILSAND PROJECT Fluor/Muskeg River Contractors (2000 - 2001)

Process engineer responsible for designing a groundwater collection system including seven wells and a network of approximately 15 kilometres of pipeline.

FLUOR DANIEL Mining & Minerals (1992 - 2000, 2003 - 2004)

Metallurgist involved with project work, feasibility studies, computer development, engineering proposals and operator training systems. Projects included base metals concentrating, smelting and refining, gold leach plant design, pyrometallurgical plant basic design, creation of computerized tools for metallurgical design engineering and writing computerized plant operator training manuals. Responsibilities included process flowsheet development, equipment sizing and specification, project feasibility cash flows, computer programming, database development and technical writing.


English- Fluent; Spanish- Functional; French- Reading ability


B.A.Sc., Mining and Mineral Process Engineering, University of British Columbia, 1992

Short Course Instructor

Using laser scanning to optimize grinding and solve common milling issues

Co-presented a short course with Tony Facciolo (Coding Metrology Inc) at the Canadian Mineral Processors AGM (CMP 2023), Ottawa, Canada.

Short Course on Comminution & Semi-autogenous Grinding

Presented on five occasions including to the public in Canada & Perú and to private customers in Canada, (2018-2019).

McGill Mineral Processing Short Course

Presented the “AG/SAG milling” module (2017, 2019, 2023), Montréal, Canada.

Geometallurgy basics

Short course presented in association with Target Rocks (2017), Lima, Perú.
Private short course presented to a mining client (2015), Cajamarca, Perú.

Bond-based Grinding Models for Design and Geometallurgy

Short course presented at the Canadian Mineral Processors AGM (CMP 2014), Ottawa, Canada.
Short course with co-presentor Peter Amelunxen presented at Procemin 2013, Santiago, Chile.

British Columbia Institute of Technology

Guest lecturer on process plant design (ongoing since 2006).
Professional Advisory Committee member for Mineral Exploration and Mining Technology department.

Professional Associations:

Board member (Trustee), SAG Conference Award Foundation;
Member, Bond Grinding Circuit Efficiency working group, Global Mining Guidelines Group;
Member, Canadian Institute of Mining and Metallurgy, Australasian Institute of Mining and Metallurgy, and
Registered Member, Society for Mining, Metallurgy, and Exploration (USA)

Peer reviewer, Minerals Engineering technical journal;
Executive Committee Member, Vancouver branch, Canadian Inst. of Mining, Metallurgy & Petroleum (1996, 1998, 2001, 2004-2012; Webmaster 2007-2012);
Branch chair, Vancouver branch, C.I.M. (2008);


Author of over 25 technical papers.
Please refer to


Address: First Floor, Penrose 1, Penrose Dock, Cork, T23 KW81, Ireland
Mobile Phone/Whatsapp/Signal: +1-778-388-2444, +353 89 982 6571
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