Modifications to the Lawrence Livermore National Laboratory (LLNL) one-dimensional retorting model are improving the predictive capabilities for evaluating laboratory retorting tests. The model is now operational on the WRI Prime computer as well as on the University of Wyoming Cyber computer system. The output format has been revised for easier interpretation and the results are incorporated into files for interactive plotting using the commercial DISPLA graphics software. A major improvement in the calculation of heat losses and the development of a rectangular particle geometry are expected to provide better comparisons between model calculations and experimental results of low void retorting tests. Samples of partially retorted shales have been prepared with a Fischer assay retort to test NMR measurement techniques. These samples qua1itatively represent the expected radiation of shale properties in the kinetic experiments. The CP/MAS 1 C NMR spectra suggest that the aliphatic carbon in the partially retorted samples has a higher concentration of short-chain alkyl substituents relative to the original shale. These spectra also suggest that the residual aromatic carbon becomes less substituted and more condensed at the higher temperatures and longer residence times for retorting. Liquid-state NMR measurements of the corresponding product oils are consistent with the solid-state CP/MAS 13C NMR results. Interrupted decoupling techniques supplement the interpretation of the solid-state NMR spectra by suggesting compositional changes in the carbon types with variations in temperature and residence time. Interrupted decoupling techniques are improving the identification of different carbon types in solid-state 13C NMR measurements. Samples of kerogen concentrates have been used to compare the interrupted decoupling spectra with the CP /MAS NMR measurement of carbon types. When the proton decoupler is interrupted to allow relaxation of only the directly bonded carbons, a 13C signal is generated by the quaternary carbons. The resulting resonances in the aromatic and carbonyl regions of the spectra are due exclusively to quaternary carbons, but there is incomplete suppression of the methyl carbons in the aliphatic region. Initial isothermal measurements of kerogen decomposition kinetics at 37SoC have been completed using identical 20-gm samples of Colorado oil shale. As expected, the kerogen conversion is accompanied by an increase in the carbon aromaticity of the partially retorted shale. The initial oil production is highly aliphatic, and the aliphatic nature of the oil declines only slightly as the conversion progresses. A new chemical model of kerogen decomposition is emerging to explain the products of decomposition resulting from chemically different moieties of kerogen having substantially different rate constants. Measurements of shale oil coking and cracking rates at isothermal conditions are planned to provide kinetic expressions to predict oil degradation in advance of an approaching retorting zone. A new apparatus has been assembled to measure the coking and cracking rates over a temperature range of 300-900o F. In this experimental procedure, cold shale oil is injected into a hot rubble bed where the volatile fraction evaporates and is swept out the top of the rubble bed, while the remaining liquid drains through the rubble. The residence time for cracking of the shale oil vapor is controlled by the sweep gas rate, and the residence time for coking of the nonvolatile liquid is varied by adjusting the shale oil injection rate. Improved correlations between retorting parameters and GC/MS diagnostic analyses have been developed for the low void volume retort. Data relating coking and cracking plus combustion have been obtained with varying void volume, resource grade, particle size, injection rate, and heating rate. The new diagnostic parameters have been applied to several runs on the 10-ton retort. In addition, relationships have been shown to exist between thermal histories (specifically, heating rates) and ratios of various thermally sensitive hydrocarbons known as bi 0- markers. A newly-purchased quadrupole mass spectrometer for analysis of gaseous kerogen decomposition products is not operable at this time. After several attempts to install the instrument, it was shipped back to the vendor for correction of problems at the assembly site. The vendor is currently repairing non-functioning circuitry.