Abstract: With the depletion of conventional resources, the development of high-altitude, cold-region mines has emerged as a strategic option to secure resource supply and drive industrial upgrading. However, driven by the dual pressures of global climate change and the “dual carbon”(carbon peaking and carbon neutrality) strategy, the mining industry—a foundational sector with high energy consumption and substantial emissions—faces significant challenges in achieving a low-carbon transition. An accurate and scientifically rigorous carbon emission accounting system is thus pivotal for achieving sustainable mining development. This study, grounded in full life cycle theory, systematically identifies carbon emission sources throughout the entire production process of high-altitude open-pit mines and delineates the accounting boundaries at the mining field scale. A comprehensive analysis is 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 multi-factor coupling carbon emission accounting model is developed by integrating high-altitude environmental parameters, equipment performance indices, mining design factors, and carbon emission factors. This model elucidates the synergistic relationships among the various stages of mining operations, equipment functionality, and carbon emission traceability. To rigorously assess model sensitivity, the study employs the Sobol global sensitivity analysis method, quantitatively evaluating the influence of each input parameter on the model’s output. Results from the sensitivity analysis highlight that physical-mechanical parameters, such as rock density, alongside key operational factors like equipment power and loading capacity, directly affect the carbon emission profile of the mining process. A case study of a high-altitude open-pit mine in Xinjiang is conducted to validate the proposed model and optimize decarbonization pathways. Utilizing a three-dimensional block model, the study quantitatively assesses unit ore emission intensities and annual total emissions. Empirical findings indicate that seasonal climate variations, mining intensity fluctuations, and stripping ratios significantly impact the overall carbon emission levels. In particular, fuel combustion and electricity consumption are identified as the primary emission sources, while transportation and crushing operations constitute major contributors to total emissions. Under equivalent production conditions, high-altitude environments are found to generate an additional 43183 t CO2 eq compared to conventional low-altitude regions. In summary, this research proposes low-carbon development strategies from both macro-policy and micro-production perspectives. The innovative integration of full life cycle theory, multi-factor coupling, and sensitivity analysis in carbon emission accounting provides a sound theoretical framework and empirical data support for energy conservation, emission reduction, and sustainable mining transformation in high-altitude, cold-region open-pit mines.