World coal prices are currently lower than recent years. Worldwide, many coal mines are operating at a loss. This has led to a massive slump in share prices. While this may be bad for coal mining companies, it is welcome for coal power generators buying coal on world markets.
A moratorium would restrict supply over time, putting upwards pressure on coal prices. This would make cleaner energy more competitive. The benefits of higher prices could accrue to existing miners or to government budgets, depending on their choice of tax policy.