In-depth survey report of St. Joe Minerals Corporation, Viburnbum, Missouri, report no. CT-111-11b.
This report concerned an in depth control technology survey made at the ore beneficiation flotation process and reagent handling area at St. Joe Minerals Brushy Creek Mill (SIC-1031), Viburbum, Missouri. Over 5,000 tons per day of a complex sulfide ore containing an average of 4 to 5% lead (7439921) were handled by the flotation process. The galena mineral was selectively floated from other minerals using a variety of reagent additions, producing a desired lead concentrate grade of 74% and lead recovery of 98%. Assessments were made of rougher flotation cell covers, covered cleaner and recleaner flotation cells and launders, and the use of a centralized flotation process control room. The rougher flotation cell covers were not effective, the covered cleaner and recleaner flotation cells and launders were moderately effective, and the centralized control room was effective in controlling airborne concentrations of the primary hazards located at the site. The three area samples collected for lead in the control room averaged 0.014mg/m3, which was 9 and 14% respectively of the MSHA Standard and the NIOSH recommended level. The concentrator operator working in the control room and flotation cell area had an average lead exposure of 0.045mg/m3 for the three shifts sampled, which was 30% of the MSHA Standard and 45% of the NIOSH recommended level.