Why did coal mining in the 1920 not boom?

Coal mining in the 1920s did not experience a boom primarily due to the rise of alternative energy sources, particularly oil and natural gas, which began to replace coal in various industries and transportation. Additionally, the post-World War I economic downturn led to decreased demand for coal, as industrial production slowed. Labor strikes and unrest among miners also affected productivity and profitability in the industry. Finally, the introduction of electricity and advances in technology reduced the reliance on coal for heating and energy.