The Queensland Government has released a new standard on the use of Polymeric Chemicals at Queensland mines. The standard will apply to a range of sealing applications at mines as well as general use of the PUR chemicals. The standard addresses underground coal industry conjecture in respect of the risks of thermal reactions from polymeric chemicals during sealing operations and the risks of exposure to personnel when using the chemicals.
The regulator says that “the health impacts of exposure to these substances were believed to be well understood; recent testing to develop this standard have identified elements that require further testing and validation”
The role of skin absorption as a significant route of exposure has only been acknowledged in recent times. As such a lack of historical biological monitoring data may have resulted in an underestimation of the potential exposure risks to coal mine workers using these substances.
“As more atmospheric and biological monitoring exposure data is gathered and a better understanding of the exposure profile for coal mine workers using these chemicals is gathered, the requirements within this standard may need to be reviewed and altered as appropriate.” the standard says.
The standard requires that Workplace inspections are to be carried out whilst pumping or injection is taking place. “All zones and areas shall be thoroughly inspected for any evidence of heating by ERZC appointed to the zone. If any excess heating is observed, pumping shall be immediately stopped and appropriate measure activated including cooling water and stone dust applied to the site”
The new standard places obligations on mines to conduct inspections when injecting PUR Seals. This may present a range of complications in emergency scenarios where seals are injected from surface operations.
“Commencing immediately following the injection of PUR and urea silicate products, the site of operation shall be inspected at intervals of not more than 30 minutes for a period of 4 hours to ensure that no undue heating occurs. This inspection should be conducted in accordance with section 305 of the CMSHR.”
“Any fire watch requirements for other types of polymeric chemicals shall be based on a risk assessment considering the reaction temperatures generated during the curing process. Whilst it is understood that production activities may recommence within this period the area of application must still be able to be observed up to 4hrs after completion of the application and this limitation is not to preclude the safe recommencement of production operations.”
The new standard is available for download here https://www.rshq.qld.gov.au/__data/assets/pdf_file/0005/1445972/recognised-standard-16.pdf
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