Integrating Sustainability into Long-Term Mine Planning: Introducing SustMine

In our case study, we evaluated 20 production schedules for an open pit gold mine. The schedule with the highest net present value, about $6.26 billion, did not make it onto the list of the most sustainable options. Meanwhile, two schedules with only middling economic scores did make it, because they performed much better on environmental and social measures. That result sums up the idea behind our new paper, "SustMine: A Framework for Integrating Sustainable Development Dimensions into Strategic Mine Planning," now published open access in Mining, Metallurgy & Exploration. The Problem: Sustainability Arrives Too Late Strategic mine planning is where the biggest decisions are made: how large the pit will be, how fast to mine, and how much processing capacity to build. These choices shape a mine's environmental footprint and its relationship with the community for decades. Yet these decisions are still made mainly on economic grounds. Sustainability usually enters later, as impacts to mitigate once the critical choices are already locked in. When researchers have tried to bring sustainability into planning earlier, two problems keep coming up. 1. Indicator selection is rarely explained. To assess sustainability, you need indicators such as greenhouse gas intensity, water use, or local employment. When we reviewed studies on production planning, pit limits, and cut-off grades, we found that most never explain how their indicators were chosen, and many address only one or two of the three sustainability dimensions. 2. Weighting is subjective. Many methods combine indicators by assigning weights: 40% economic, 35% environmental, 25% social, for example. But weights reflect whoever sets them. Two expert panels can produce two different "best" mine plans from the same data. Even statistical weighting methods carry hidden assumptions. Our Answer: Two Connected Tools SustMine addresses both problems with two sub-frameworks that work together. Part 1: Choosing the right indicators, systematically Every mine is different. Its deposit, processing method, location, regulations, and community all shape which sustainability issues matter. So SustMine starts with the specific site and the specific planning decision, rather than a fixed checklist. Here's an example from our case study. The mine processes ore by heap leaching, which produces no tailings, so tailings management was not included as an issue, even though it would be central at most other mines. Candidate indicators come from sources such as the GRI standards, SASB, ICMM guidance, the UN Sustainable Development Goals, regulations, expert input, and the published literature. Each candidate then goes through five criteria in two levels: Level A (strict filter): Is the indicator applicable to this planning activity? Is it relevant to this site? Is it measurable? An indicator that fails any of these is removed. Level B (flexible filter): Is the data available, and is it of good quality? At the early planning stage, data is often incomplete, so an indicator can pass with a "partly" rating as long as the user documents the justification and the assumptions. One rule I consider important: if an issue matters but can't yet be measured, SustMine doesn't quietly drop it. It is kept out of the numerical analysis to avoid adding noise, but it stays in the written decision record so decision-makers remain aware of it. Part 2: Comparing alternatives without weights To compare plans, SustMine uses Pareto fronts, a concept from multi-objective optimization. Think of buying a car based on price, fuel economy, and safety. If one car is worse than another on all three, you can rule it out. The cars left, where each is better than the others on at least one measure, form the "first front." Choosing among them is a real trade-off, but none of them is clearly inferior. SustMine applies this idea in two stages. First, it ranks the planning alternatives into fronts separately within each dimension: economic, environmental, and social. Then it runs a second Pareto analysis on those three rankings to produce an overall Sustainability Composite Index (SCI). An SCI of 1 means no other alternative beats it across the board. No weights are needed at any stage. Testing It: A Hybrid Case Study Real mining data is often confidential, and detailed social data is rarely published. So we built a hybrid case study. The technical and economic data came from a real gold project's Technical Report Summary. The social context came from an established community acceptance study conducted in Utah. Using GEOVIA Whittle, we generated 20 production schedules by varying capital cost, mining rate, and processing capacity. We identified 12 sustainability issues and 20 candidate indicators. Five indicators were removed during selection. Four failed the applicability test, and one, post-mining land income, failed because reliable data wasn't available. That left 15 indicators: 3 economic, 8 environmental, and 4 social. What We Found Five schedules reached the first front. Schedules 1, 2, 5, 6, and 11 each earned an SCI of 1. The trade-offs were visible. Schedules 6 and 11 scored only 3 out of 4 on the economic dimension but still reached the first front because of their strong environmental and social performance. Schedule 9 had a top economic score but ended up on the third front because its environmental and social results were only moderate. The environment drove most of the differences. Environmental scores varied the most across schedules, ranging from 1 to 7, driven by GHG intensity, air emissions, land occupation, waste, and acid rock drainage potential. Some indicators barely changed, and that told us something. Social scores varied less than the others because two of the four social indicators, pit utilization and operational safety, depend on pit geometry, which barely changes between schedules. This isn't a weakness of social indicators in general. It shows how important it is to choose indicators that respond to the decision being evaluated. The results held up under testing. Changing the normalization method, the classification threshold, or leaving out one indicator at a time did not remove Schedules 5 and 11 from the first front. For 10 of the 15 indicators, removing that indicator changed nothing in the rankings, so no single indicator drives the result. Acting as the decision-maker, we chose Schedule 5. It scored at the top in both the economic and environmental dimensions and was moderate on the social dimension, where the differences between schedules were small anyway. A note on these results: the case study combines data from two different contexts, so it is meant to demonstrate the method, not to recommend a plan for any real mine. Why This Matters SustMine does not claim that one plan is "the sustainable one." Its purpose is to show decision-makers the full set of trade-offs, clearly and without hidden weights, while there is still time to act on them. A composite index also makes those trade-offs easier to explain to regulators, investors, and communities who won't read raw indicator tables. As mining expands to meet demand for critical minerals, including in Saudi Arabia, frameworks like this can help make sustainability part of the plan from the very beginning. What's Next We plan to apply SustMine to other planning decisions, including cut-off grades and ultimate pit limits, and to case studies where all the technical and social data come from the same site. We also plan to add uncertainty modeling, for example with Monte Carlo simulation or fuzzy logic. Read the paper (open access): Altalhi H, Awuah-Offei K, Nicolosi G, Al Moinee A, Al Habib N (2026). SustMine: A Framework for Integrating Sustainable Development Dimensions into Strategic Mine Planning. Mining, Metallurgy & Exploration. https://doi.org/10.1007/s42461-026-01658-1 Code and data: The indicator selection spreadsheet, quantification methods, and MATLAB scripts are available on GitHub. I'm grateful to my co-authors at Missouri University of Science and Technology and to the Saudi Arabian Cultural Mission (SACM) for funding this research. Questions or collaboration ideas? Get in touch.