Disposal of massive amounts of spent shale will be required if an oil shale industry using surface retorting is developed. Field studies were initiated in 1973 on two types of spent oil shale--coarse-textured (USBM), and fine-textured (TOSCO). The objectives of these studies were to investigate surface stability of and salt movement in spent shales and spent shales covered with soil after vegetation has been established by intensive treatment and then left under natural precipitation conditions. The plots were established at low-elevation (1,700 m) and high-elevation (2,220 m) study sites in northwestern Colorado. A good cover of native species was established on all plots by leaching, N and P fertilization, seeding, mulching, and irrigation. High levels of Mo were found in plants grown in the spent shales compared to plants grown in soil. Resalinization occurred following leaching of the TOSCO spent shale. The greatest runoff was from the TOSCO spent shale. Runoff was moderately to highly saline.

Prepared by Dept. of Agronomy, Colorado State University, under grant no. Includes bibliographical references (page 68).