This paper presents experimental results on the growth of ash deposits of JinYang (JY) coal and blends (with additive) tested in a pilot-scale furnace. The additive used in the experiment was atacamite [Cu2Cl(OH)(3)]. The digital image technique was used to monitor the morphology of ash deposit growth and to determine the change in thickness of the deposits with time. Two type K thermocouples were installed in the oil-cooled deposition probe to measure the temperature of the inner and outer surfaces of the deposition probe. This work indicated that the process of ash deposit growth included four stages. For pure coal, the growth rates of deposits on the second probe were 0.079, 0.034, 0.045, and 0 mm/min, corresponding to stages 1, 2, 3, and 4, respectively. Growth rates of the additive blends were 0.056, 0.053, 0.017, and 0 mm/min for the four stages mentioned above. According to these results, the additive could slightly reduce the thickness of the ash deposits of JY coal and the stable thicknesses for pure coal and additive blends were 6.1-6.3 and 5.05-5.15 min, respectively. It was demonstrated that this additive could result, in augmentation of the coefficient of thermal conductivity of the ash, deposit in high-temperature regions (T >= 1250 degrees C) while promoting the thermal resistance of the ash deposit in low-temperature regions (T <= 1200 degrees C). This may be a result of the production of deposit constituents other than those of the pure coal with the addition of the additive. The focus of our future Work would be to investigate this mechanism further.