This was just one of a number of statistics published in the New South Wales Minerals Council State of the Industry Report released this week.
The NSW minerals industry, propped up heavily by coal, is one of the biggest sectors in the state's economy, with an annual production value of $12 billion.
Coal accounts for about 80% of the total value, with more than 90% of the state's power supply generated from coal.
According to the council's report, the minerals industry contributes more than $1.5 billion per year to government revenues.
More than 47,000 people are directly employed in the minerals and minerals processing industry, with about 200,000 indirectly employed in support industries.
Underground coal mines employed 6510 people in 2007.
The average age of an underground coal mine employee in December 2006 was just over 42 years of age.
The export of Australian mining equipment, technology and services accounts for more than $5 billion per year.