Mining needs to reduce its operating and environmental footprint and more underground extraction, and less surface mining, will undoubtedly play a part, according to AMC Consultants CEO Andrew Hall. He thinks a faster transition underground needn’t compromise standard economic models that have historically favoured openpits.
“From an ESG perspective underground mining typically provides a significant number of benefits compared to openpit methods,” Hall told the 2025 AusIMM Underground Operators Conference in Adelaide, South Australia.
“Further, the inclusion of ESG considerations into the evaluation of the optimal transition point can provide a compelling business case to mine a small, or no, openpit and commence underground operations earlier in the mine life.
“Mine planners – and all of us mining professionals – have an important role in ensuring that decision makers are fully informed and understand the trade-offs between strategic options to enable the selection of the best strategy to deliver the corporate goals and ensure a prosperous and cleaner future.”
AMC, an internationally renowned specialist in the mining technical consulting arena, maintains the industry’s most comprehensive underground hard-rock mine benchmarking database.
Hall said decisions on where and when openpits became underground operations continued to be “widely debated”. Standard project evaluation methods were “typically not comprehensive or holistic”. They tended to focus on what was feasible rather than what was optimal.
“ESG criteria have not traditionally played a role in mine optimisation or assessing project viability, with measures to reduce ESG impacts considered after the preferred mining strategy is selected, resulting in an outcome that is typically not strategically optimal,” he said.
ESG factors were often an outcome of an evaluation and dealt with at the back-end of a study. Hall said delivering “better outcomes” for all stakeholders required a paradigm shift: ESG considerations had to be fully integrated into the project evaluation process.
“As stakeholders demand more environmentally and socially responsible mining practices, integrating ESG considerations into the development of mine strategy is both an imperative and a strategic advantage,” he said.
Hall said “optimisation” itself had become an over-used buzzword. Mine optimisation typically zeroed in on a component of a mining system, such as a mine schedule, to ratchet up net present value or some other specific objective.
“Component optimisation won’t result in the entire operation or enterprise being optimal,” he said.
“Strategy optimisation differs from mine optimisation in that it models all components of the mining system along with all the practice options under each of the possible scenarios to achieve the desired strategic goals.
“When I say options I’m talking about the strategic choices over which we have control such as production rates and cut-off grades, as opposed to scenarios which are the things we can’t control such as metal prices and exchange rates.
“By modelling all the relationships within the mining system, the trade-offs between achieving different goals such as financial, ESG, production and the quantity of resources and reserves can be fully understood.
“This enables informed selection of the strategy that best meets the corporative objectives such as achieving strong and robust cash returns while minimising environmental and social impacts.”
