Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/518784
p: 502.499.6198 f: 502.499.1079 phoenix@dewater.com www.dewater.com 2402 Watterson Tr, Louisville, Kentucky 40299 PHOENIX HYDROSORT™ Hindered Settling Classiers: for sand classication and/or deleterious material separation PHOENIX WX Belt Filter Presses: for slurry dewatering & water recovery PHOENIX/F&B Recessed Chamber & Membrane Filter Presses: for slurry dewatering & water recovery PHOENIX HiFlo™ & AltaFlo™ Thickeners: for slurry thickening, volume reduction & water clarication PHOENIX/KISA Bucket Wheels: for dewatering & classication of sand, gravel & other granular bulk materials for slurry dewatering & water recovery for slurry dewatering & water recovery for slurry dewatering & water recovery PHOENIX HiFlo™ & AltaFlo™ Thickeners: PHOENIX HiFlo™ & AltaFlo™ Thickeners: cubic meter of air, calculated as an 8-hour time-weighted average. The current PEL is 100 micrograms per cubic meter of air for general industry and 250 micrograms per cubic meter of air for construction and shipyards. These exposure levels apply to all employees, and not just employees who may be working directly with silica. In other words, OSHA- regulated employers will have to develop a monitoring plan that takes into account the nature of the work place. For example, in the oil and gas industry, fracking does not fall under the category of construction, but is under the general industry/maritime standard. OSHA recognizes that fracking presents unique challenges because exposure to silica is expected to be over a large area. Similar to highway con- struction projects, OSHA recommends that the oil and gas industry opt for a written access control plan in lieu of a regulated area. Written plan requirements A written access control plan must contain provisions for a person to identify any areas where exposure to respirable silica exceeds, or reasonably could be expected to exceed, the PEL. Employees must be notified of these areas, and the areas must be demarcated from the rest of the work- place. These requirements apply to all employees, even if the workers are temporary or work for another employer, such as a subcontractor. The employer using silica is required to educate other employers on site as to any required precautionary measures. The plan must also con- tain provisions for limiting access to areas where silica is or could exceed the PEL to limit the number of employees exposed. With regard to engineering controls to limit dust exposure, OSHA identified four categories: substitution, isolation, ventilation, and dust suppression. OSHA believes that engineering controls offer reliable and consistent protection. Personal respirators are not considered dust control by OSHA and can only be used if engineering controls, combined with work practice con- trols, cannot bring the respirable levels of silica below the ROCK LAW • 24