Report on an in-depth survey of silica flour dust during packing, transfer and shipping at the Central Silica Company (Glass Rock Plant) Glass Rock, Ohio, report no. CT-120-12a.
A visit was made to the Central Silica Company, Glass Rock, Ohio, to evaluate methods used to control employee exposure to silica (14808607) dust. The control methods at this company included careful handling and transfer of damp materials, exhaust ventilation, good housekeeping procedures, and the use of respiratory protection. Evaluations were made of the packing area, transfer point, inside loading trucks, and ambient air at sections of the flour building. Control systems included a good exhaust ventilation system and four ventilation hoods. Evaluations were made of samples collected by an MSA gravimeter dust sampler, the Del High volume electrostatic precipitation, and bulk and rafter samples. Dust control methods appeared to be effective due to the existence of good engineering controls, good work practices, and an effective respiratory protection program. Additional control measures included the handling of the ore as a damp material, thus reducing the generation of dust particles. Outside dust sources were being reduced by resurfacing roads, planting vegetation and wetting road surfaces with salt water. Most of the product was shipped in bulk, cutting out the dust generated through bagging and shipping. Plastic wrapping was used around pallet loads to reduce bag breakage and dust dispersion. A filtered air system controlled low dust levels in the Pebble Mill control room. Enclosed screens operated under negative pressure separated fines from coarse product at the process building.