Pacific Asbestos Corporation Dust Collection Proposal, Purchase Order and Operations Report, Copperopolis Mill (1972)

Four pages from the files of the Pacific Asbestos Corporation at Copperopolis, California, a chrysotile mine and mill then owned by the H. K. Porter Company. Two pages are Western Precipitation proposal 342-1076-AO of May 18, 1972, for Pulseflo bag-filter dust collectors on the mill's vertical and horizontal dryers, mill building and rock storage. The third is Pacific Asbestos's purchase order of June 6, 1972, to the Western Precipitation Division of Joy Manufacturing Company "to furnish and erect a complete dust collection system for $336,693.00," billed to H. K. Porter Company. The fourth is the mill's operations report for August 1972, dated September 1, 1972.

What it shows

The papers show a new dust collection system being bought for the Copperopolis mill in mid-1972, a few months after the federal emergency asbestos standard. The operations report gives the mill's output: for the year to date, 695,152 tons of ore mined, 403,292 tons fed to the mill and 19,538.50 tons of fiber produced, a fiber recovery of about 4.5 per cent, with production broken down by grade.