Abstract: Amid the depletion of conventional resources, the development of high-altitude cold-region mines has emerged as a strategic avenue to secure resource supplies and drive industrial upgrades. However, under the dual pressures of global climate change and the “dual carbon” (carbon peaking and carbon neutrality) goals, the mining industry—characterized by high energy consumption and substantial emissions—faces significant challenges in achieving a low-carbon transition. In high-altitude and cold-region mining areas, low-temperature and low-pressure environments significantly reduce fuel combustion efficiency, blasting performance, and equipment productivity, thereby increasing energy consumption and carbon emission intensity compared with conventional mining regions. To facilitate accurate and scientifically robust carbon accounting in high-altitude, cold-region open-pit metal mines—and to inform rational decarbonization pathways focused on source reduction in mine design—this study adopts a life cycle assessment framework to systematically identify emission sources across the entire production process and delineates the accounting boundaries at the mining field scale. A comprehensive analysis was conducted on the effects of high-altitude factors—specifically atmospheric pressure and oxygen concentration—on fuel combustion efficiency and blasting performance. Building on these insights, a multifactor-coupled carbon emissions accounting model was developed by integrating high-altitude environmental conditions, equipment performance metrics, mining design parameters, and carbon emission factors. This model elucidates the synergistic relationships among the various stages of mining operations, equipment functionality, and carbon emission traceability. The Sobol global sensitivity analysis method was employed to quantitatively evaluate the model sensitivity to input variability, enabling a robust assessment of the influence of each input parameter on the model output. The sensitivity analysis reveals that physical-mechanical parameters such as rock density, in conjunction with key operational factors such as equipment power and loading capacity, directly influence the carbon emission profile of the mining process. A high-altitude, cold-region, open-pit metal mine in Xinjiang was selected as a case study for model implementation and optimization of the decarbonization pathways. Using a three-dimensional block model, this study quantitatively assessed unit ore emission intensities and annual total emissions. The empirical findings demonstrate that seasonal climate variations, mining intensity fluctuations, and stripping ratios significantly influence overall carbon emission levels. In particular, fuel combustion and electricity consumption were identified as the primary emission sources, whereas transportation and crushing operations constituted the predominant contributors to total emissions. Under equivalent production conditions, high-altitude environments generated an additional 43183 t CO₂ compared with that of conventional low-altitude regions. Based on the accounting and analysis of the case study, low-carbon development strategies for high-altitude and cold-region mines are proposed from both macro-policy and micro-production perspectives. At the micro level, strategic measures must focus on optimizing extraction schedules, upgrading electrically powered mining equipment, and designing energy-efficient haulage routes. At the macro level, policy recommendations must emphasize on promoting the substitution of fossil fuels with renewable energy sources, refining unified accounting standards, and implementing robust inspection and evaluation protocols. The multifactor-coupled carbon emission accounting model developed within the life cycle assessment framework provides a theoretical foundation and empirical reference for carbon accounting, energy conservation, consumption reduction, and the green transformation of high-altitude and cold-region open-pit metal mines. This study provides a valuable reference for informing the mining sector’s green and low-carbon development aligning with the “dual carbon” objectives.