This paper shows information and data about the physical characteristics of coal ash samples generated in power plants that burn coal. The study focuses on mineral technology and the objectives are both the economic uses and sustainable environmental management for the waste. The methods applied are related to particle size distribution, colorimetry, density and grindability. The main results are: bottom ash and fly ash generally have D50, respectively, < 0.6 mm and < 20 µm; the brightness values ​​in both ashes vary widely, indicating variations in the presence of unburned coal in the samples of three power plants; the densities in both ashes ranging from 2.16 to 2.33 g/cm3, indicating homogeneity among them; the Bond Work Index value is 11.9 kWh/t in a sample of bottom ash, indicating that the material is easy to grinding. These results suggest that physical characteristics of the bottom ash, as the fly ash, also can be applied as an additive to the cement industry, using grinding processes with low operating cost.