Mining industry development, enforcement intensity of security policy and intra-city development disparity

China, the world's largest developing country, is rich in mineral resources, albeit unevenly distributed geographically. Some cities with a surplus of mineral resources may form path dependence on these natural resource industries, leading to imbalanced urban development and widening development disparities within cities. However, in the event of safety incidents in the mining industry, local governments are compelled to regulate the excessive development of the mining sector and enhance the enforcement intensity of safety production policies. This study, based on the measurement of the Gini coefficient using nighttime light data for 281 prefecture-level cities in China, manually compiled the locations and death tolls of mining industry production safety incidents from 2001 to 2020, established an empirical analysis framework based on the instrumental variable two-stage least squares method. The research findings indicate: (1) Since the beginning of the 21st century, China's mining industry has experienced significant growth propelled by market-oriented reforms. However, it has also played a notable role in widening development disparities within cities. Robust results were obtained through instrumental variable estimation using the standard deviation of urban ground slope as a geographical indicator. (2) The occurrence of safety incidents in the mining industry will immediately escalate the enforcement intensity of regional safety policies, creating a significant inhibitory impact on alleviating the widening development disparities within cities caused by the expansion of the mining industry. In the case of larger safety incidents with a death toll of 3 or more, this impact will become even more pronounced. (3) Heterogeneity analysis reveals that the outlined mechanism is prominently present in the middle area, where the mining industry is relatively developed. In contrast, there is no significant correlation between the occurrence of safety accidents and the escalation of safety policy implementation intensity in the economically developed eastern region and the western region with lower levels of infrastructure development. However, in cities with a higher proportion of the mining industry, the aforementioned relationships remain stable. (4) Once a mining accident involving fatalities occurs in a prefecture-level city, local governments generally strengthen the enforcement of safety policies, comprehensively eliminate hidden dangers in production safety. This shift leads to a reversal in the impact of the mining industry on the development disparity within the city, changing from an expansion to a reduction effect. Moreover, this reduction effect persists for five years. In the case of a serious safety production incident resulting in 10 or more deaths, the impact of increased implementation of safety policies also extends for a prolonged period of five years. This article makes a clear marginal contribution to enrich the study on the effects of China's mining industry safety policies.