Mercury in oil shale from the mahogany zone of the Green River formation, eastern Utah and western Colorado

Mercury has been reported in concentrations as high as 4 parts per million from oil shale in the Green River Formation near the Federal oil-shale prototype lease-tracts U-a and U-b in eastern Utah. This high concentration of mercury if present throughout a minable zone, would be of concern in commercial oil-shale operations processing large volumes of shale. Using an improved analytical method, surface samples from eastern Utah previously reported to contain high concentrations of mercury were reanalyzed, and an additional 183 drill core samples from the Mahogany zone and adjacent beds were analyzed. The reanalyzed samples averaged slightly more than 0.35 ppm mercury and the drill-core samples averaged 0.37 ppm. The products from a Fischer assay of 100-gram sample of oil shale, found to yield 35 gallons pier ton of oil and 43 ppm of mercury, were analyzed for their mercury content. The spent shale contained only 2 percent of the total mercury in the assay products and the gas fraction contained about 58 percent.