Interpretation of fischer assay data for the evaluation of analcime-bearing oil shale in the Green River Formation, Colorado and Utah

Using Fischer assay data, an empirical method has been devised for distinguishing analcime-rich oil shale from oil shale which is essentially free of analcime in the Parachute Creek Member, Green River Formation, Colorado and Utah. This method permits evaluation of Fischer assay data in order to compute saline mineral resources and also permits detection of abundant analcime which may be important to processing methods used in aluminum recovery. The method also eliminates the need for X-ray diffraction analysis to determine analcime distribution. For all of the potentially commercial oil-shale zones in the Piceance Creek basin, analcime appears to be most abundant near the basin margins, and least abundant or absent in the middle of the basin. When analcime, dawsonite, and nahcolite are subjected to Fischer assay pyrolysis as components of oil shale, they react differently than is predicted by thermal studies of the pure minerals.