|
Silicosis and Silica News - Return to Menu
New quartz references for workplace safety
Chemists at the National Institute of Standards and Technology (NIST) have developed a new set of reference materials that could contribute to significant improvements in workplace safety through more accurate measurement of the amount of quartz dust in the air.
Crystalline silica or quartz is one of the most common minerals on Earth. When finely powdered silica gets in the air it becomes a significant health hazard. Respirable quartz is associated with the development of silicosis, lung cancer, pulmonary tuberculosis and other airway diseases. The National Institute for Occupational Safety and Health (NIOSH) has estimated that at least 1.7 million U.S. workers are exposed to respirable crystalline silica in a variety of industries and occupations, including construction, sandblasting and mining (1991 data). Other industries with significant exposure include building construction and medical and dental laboratories. To help safeguard workers, the Occupational Safety and Health Administration (OSHA) enforces strict regulatory limits on the emission of respirable crystalline silica in the work place.
Monitoring silica dust in the workplace typically is done by collecting samples over a period of hours on a special air filter and using X-ray diffraction (XRD) to determine the amount of silica present in the sample. To be effective, monitoring requires accurate measurements of micrograms of silica on the filters, which in turn requires precise calibration of the measurement system. NIOSH has identified calibration errors as a significant factor in inconsistent results from different laboratories.
To help environmental laboratories perform these demanding calibrations, NIST has developed a series of Standard Reference Materials (SRMs) with precisely measured quantities of respirable quartz deposited on typical filters. The NIST materials cover the range between 5 micrograms and 1000 micrograms of quartz per filter, the typical range encountered in the field, and can be used to validate the accuracy of lab measurements needed to meet OSHA regulations. The reduction to ash technique must be used to prepare the quartz-on-filter specimens for XRD measurements. Details on SRM series 2950--2958, "Respirable Alpha Quartz on Filter Media" are available at https://srmors.nist.gov/tables/view_table.cfm?table=105-10.htm.
A related series of reference materials using cristobalite, the second-most important form of respirable crystalline silica, also is being developed. Standard Reference Materials are among the most widely distributed and used products from NIST. The agency prepares, analyzes and distributes well over a thousand different materials that are used throughout the world to check the accuracy of instruments and test procedures. - National Institute of Standards and Technology (NIST)
Many mines fall short of health and safety targets
By Angus Macmillan
Jun 08, 2007 - South Africa’s mining companies did not achieve the 20 percent improvement in health and safety levels that they set for themselves last year.
They are now resorting to a form of self-assessment and peer-to-peer engagement in an attempt to achieve a zero-harm goal set for 2013, Lazarus Zim, president of the Chamber of Mines, said yesterday.
Zim said at a media conference, following the third Chamber of Mines Health and Safety Summit: “It was disappointing that the industry did not improve its safety performance appreciably in 2006. It was a considerable blow.
“This is sad, particularly when you think about the loved ones of the 199 miners who lost their lives (down from 202 deaths in the previous year).
“One death is one death too many. We don’t want to accept that anyone has to die in this industry.”
Good news for the industry, however, was that last year had the lowest number of deaths from large incidents (four or more deaths in one incident).
Zim said he was optimistic that the non-gold sector could improve by 20 percent a year to achieve the 2103 target, but he said the gold sector would have to improve by 26 percent a year to reach the objective.
Sietse van der Woude, the chamber’s safety adviser, told the conference that falls off ground were still the largest contributor to deaths in the industry.
But he said deaths from seismic activity underground had been reduced.
Dr Fazel Randera, the chamber’s health adviser, said: “Silicosis and noise have been identified as health issues that need to be tackled.
‘‘We want to ensure mining operations have silica levels reduced in 2008.”
|
