An AFB fly ash sample from Georgetown University shows a significant difference in visual appearance to that of other AFB fly ash sources. Differences in the chemical composition of spent bed residue samples from Rivesville, West Virginia, are probably attributable to variations in the calcium to sulfur ratio in the fluidized-bed during combustion. Comparison of the particle size distribution of spent bed samples from Alliance, Ohio, and Georgetown University reveals a close similarity in the basic sizing of these materials, with each being considered in the medium to coarse sand size range. Visual inspection of the separated overflow sample from mineral cyclone separation indicates that this product may contain a relatively high percentage of lime. On the basis of available data, it appears that detrimental volume expansion in road base compositions containing AFB residue can be reduced to a tolerable level by pre-treatment, such as grinding and/or maximum hydration prior to use. Additions of relatively low percentages of AFB residue to acid mine waste-water resulted in significant increases in the percentage of solids of vacuum filtered samples, due to the low solids content of the wastewater sample. The addition of AFB residue to acid mine wastewater is effective in neutralizingmore » the pH and dewatering the waste, although previous neutralization tests have shown that milled AFB residue is generally more reactive and effective than as received AFB residue. Combinations of equal weights of AFB residue and fly ash appear to produce relatively high strength block. Blocks with 80 percent AFB residue and 20 percent fly ash exhibited somewhat lower strengths with little or no cracking.« less