Queensland Commissioner for Mine Safety and Health Kate du Preez said 0.9% of all dust samples - coal dust and respirable crystalline silica - taken in Queensland's coal mines in 2017 exceeded the legislated occupational exposure limit compared to 3.9% in 2016.
"Across the two most at-risk similar exposure groups for all underground coal mines in 2017, the average respirable coal dust and respirable crystalline silica concentrations were less than 50% of the OEL [3 milligrams per cubic metre for coal dust and 0.1mg/cu.m for silica dust]," du Preez said.
"There were also good results across surface coal mines in 2017 with all mines recording average results significantly lower than the OEL for respirable coal dust and respirable crystalline silica concentrations," she said.
Du Preez said one of the key contributory factors was the substantial regulatory changes which increased the level of monitoring of mine dust across all mines in Queensland.
"In January 2017, the Coal Mine Safety and Health Regulation 2017 was amended to require all Queensland coal mines to report respirable dust monitoring results, as well as any single exceedance of the OEL to the Queensland Mines Inspectorate," she said.
"In addition, recognised standard 14 and recognised standard 15 were developed to assist coal mines meet their reporting requirements."
Du Preez said the positive results showed that the state's 54 active coal mines had learned a significant lesson from the re-emergence of mine dust lung diseases and that all 34,400 Queensland coal mine workers were now working in safer conditions.
Progress has also been made in relation to respirable crystalline silica in mineral mines and quarries with the issuing in July of a revised Queensland Guideline 02 Management of Respirable Crystalline Silica in Queensland Mineral Mines and Quarries.
"This revised guideline now requires all dust monitoring to be reported to the Department of Natural Resources, Mines and Energy," du Preez said.
"To facilitate this, the Queensland Mines Inspectorate has completed significant work in conjunction with industry to consolidate more than 600 similar exposure groups to 73 reporting classes in both surface and underground mines and in quarries.
"This has allowed for a database of dust results from mineral mines and quarries to be established, which will allow for better comparison and identification of emerging trends in these types of operations.
"While I am pleased with these results, I urge the industry to maintain its vigilance and awareness of the hazards posed by respirable dust and continue to seek ways to minimise dust levels and improve risk reduction strategies for workers."