Improving eco-efficiency in coal mining area for sustainability development: An emergy and super-efficiency SBM-DEA with undesirable output.

The coal industry is an essential energy industry in China. From 2008 to 2020, the global economic crisis, the policy of de-capacity, and the decline of the coal industry all profoundly affected the development of coal mining areas. This paper combined emergy synthesis and super-efficiency Slacks-Based Measure-Data Envelopment Analysis (SBM-DEA) considering undesirable output to evaluate the eco-efficiency in the Longkou coal mining area's circular economy industrial chain from 2008 to 2020. This research finds that the eco-efficiency in the coal mining area was 0.73 in 2008 and then showed an upward trend from 2008 to 2020. The eco-efficiency was relatively effective in 2011, 2013–2016, 2018–2020. Due to the progress in mining technology and the decline in waste emission, the eco-efficiency showed an upward trend, and the peak eco-efficiency value was 1.26 in 2019. The circular industrial chain contributed a lot to the high eco-efficiency in general. The eco-efficiency in 2012, 2017 was low owing to the recession of the coal industry and the overcapacity of coal. According to the analysis results, the coal mining areas should develop circular economy, cleaner production, and extend the circular economy industrial chain. In addition, the coal mining areas ought to expand enterprise-scale, develop new energy industries (e.g., biomass energy, wind energy, photovoltaic power generation). • Evaluated eco-efficiency in the coal mining area's circular economy industrial chain. • Emergy synthesis combines undesirable super-efficiency SBM-DEA is verified. • Eco-efficiency showed an upward trend from 2008 to 2020. • The recession of coal industry and overcapacity of coal affected eco-efficiency. • Coal mining area should develop circular economy, cleaner production. [ABSTRACT FROM AUTHOR]