Based on economic principles and historical observations regarding mining booms, the statement that is generally true is:
Property values tend to increase in the short term.
During a mining boom, there is often an influx of workers seeking jobs, which can increase demand for housing and other services, leading to a rise in property values.
The other statements may not hold true consistently across different regions or scenarios. For example, unemployment rates typically decrease during a boom due to job creation, the long-term economic growth may depend on various factors beyond the boom, and the population growth may not be sustained once the boom ends.