In opal mining terms, a ballroom is a large underground cavity often without pillars or roof supports. Mr Kotru said the ballroom underneath the roadworks was "maybe nine metres high and 50 metres ...

Mr Stutley's mining partner ... to constant demand from India and China, as well as an opal renaissance in western markets such as the US. While Mr Stutley and Mr Saunders are still waiting ...

Narrator: High-quality black opal can cost over $10,000 per carat, making it one of the world's most expensive gemstones. But mining black opal isn't easy. After investing tens of thousands of ...