Preliminary Results on Testing a Field-Based Respirable Silica Monitoring Approach in Surface Copper Mines

Details

• Personal Author:
  Cauda, Emanuele G. ; Chubb L ; Lutz E ; Reed R
• Description:
  Objective: The first objective is to assess the performance of the Direct-on-Filter (DoF) FTIR technique for the estimation of crystalline silica in respirable dust samples collected in surface copper mines. The adoption of this technique could allow field-based silica monitoring in the future. The second objective is to investigate the variability of the crystalline silica content in the respirable dust present in surface copper mine operations in Arizona. Methods: Area samples of respirable dust were collected at several copper mines in Arizona, in different areas of the mine except for the pit. Primary and secondary crushers, together with the mill were selected as preferred sampling areas for the high levels of respirable dust and crystalline silica generally present in those environments. After the collection, the samples were analyzed with a portable FTIR set up for DoF analysis for the estimation of collected crystalline silica. Because this approach does not destroy the sample, the same samples were then analyzed by an accredited laboratory with the X-ray diffraction NIOSH 7500 method for the quantification of crystalline silica. The accuracy of the DoF-FTIR estimation compared to the results of the NIOSH 7500 method was evaluated for each sample and analyzed statistically within the same set and among sets collected in different mines. The identification and quantification of the minerals present in the respirable dust in different areas of every mine was also conducted to investigate the effect of geological confounders in the silica quantification with the FTIR method. Finally, the respirable crystalline silica results obtained were used to investigate the spatial variability of both respirable crystalline silica concentration within the same mine and crystalline silica content in the dust among different mines. Results: The estimation of the DoF-FTIR technique correlates well with the results of the standard NIOSH 7500 method. The accuracy of the estimation is independent from the amount of the silica present in the samples collected in different mine. More comprehensive analysis will be given at the meeting. Finally, the DoF-FTIR technique showed an LOQ for the estimation of silica of 15 micrograms. Conclusions: The exposure to respirable dust containing crystalline silica is a recognized occupational hazard in mining. In surface copper mines, activities in the crusher and mill areas are known sources of respirable dust with mass concentrations that can vary in time and can rise above action levels. In general, the monitoring of crystalline silica dust is still conducted with the use of traditional hygiene practices with limitations in terms of timely information available for the adoption and optimization of control technologies. The use of a field-based silica monitoring approach can allow operators to obtain early detection of concentration levels above the action limit. [Description provided by NIOSH]
• Subjects:
  Dust Mining Occupational Health Safety Silicon Dioxide
• Keywords:
  Crystalline Silica Dust Samplers Exposure Assessment Respirable Dust Sampling Methods
• Series:
  Mining Publications
• Publisher:
  American Industrial Hygiene Association
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Arizona ; Maryland ; OSHA Region 3 ; OSHA Region 9 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PMRD - Pittsburgh Mining Research Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  56-57
• NIOSHTIC Number:
  nn:20065995
• Citation:
  AIHce 2016: American Industrial Hygiene Conference and Exposition Pathways to Progress, May 21-26, 2016, Baltimore, Maryland. Falls Church, VA: American Industrial Hygiene Association, 2016 May; :56-57
• Contact Point Address:
  E. Cauda, CDC/NIOSH, Pittsburgh, PA
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2016
• Peer Reviewed:
  False
• Source Full Name:
  AIHce 2016: American Industrial Hygiene Conference and Exposition Pathways to Progress, May 21-26, 2016, Baltimore, Maryland
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:11b6019080d99285def79499b39326d4dd03bdc579735f5c206f4042b949b282abbc84f0b80696df37bb38286ef0c84334896020f37bd1bb983fe619cd04851b
• Download URL:
  https://stacks.cdc.gov/view/cdc/215227/cdc_215227_DS1.pdf
• File Type:
  [PDF - 1.41 MB ]