1. waste rock or earth from mining operations
Usage: mining; chiefly Australian and British
2. rubbish or refuse material
Usage: informal; chiefly Australian

Examples

• The miners dumped the mullock in large heaps beside the shaft.
• Years of excavation had created mountains of mullock around the gold mine.
• The old mullock heaps were eventually landscaped and planted with native vegetation.
• He sorted through the mullock pile looking for any overlooked minerals.
• The company had to dispose of tons of mullock from the copper extraction process.
• Don’t throw that mullock in my garden – find a proper dump site.